COMPLETE DENTURE PROSTHODONTICS
A Manual For Clinical Procedures
Bernard Levin, D.D.S., M.Ed., Professor Emeritus
Glenn D. Richardson, D.D.S., M.S., Associate Professor Emeritus
University of Southern California School of
Dentistry
17th Edition 2002
TABLE OF CONTENTS
Page 1 Acknowledgments.......................................................................................
Goals............................................................................................................
General Policies..........................................................................................
Assignment of Patients...........................................................................
Types of Denture Service........................................................................
Diagnosis and Treatment Planning........................................................
Length . . of Treatment Time and Appointments........................................
Clln~calRequirements.............................:...............................................
Frank M.Lott and Bernard Levin Awards...............................................
Outline of Denture Technique...................................................................
First Visit Diagnosis, Prognosis, and Preliminary Impressions..........
Diagnosis and Prognosis........................................................................
Exarr~ination- Diagnostic Aids, Age, Sex, and Occupation.....................
Edentulous History, Residual ridge, and Ridge Relationship..............
Palatal Seal Area.................................................................................
Gag Reflex, Border Attachments, and Soft Tissues............................
Tongue Position, and Mobility of Floor of Mouth..................................
Lateral Throat Form and Saliva...........................................................
Amount of Saliva, Radiograms, and Attitude of Patient.......................
Commmunicating With Patients.........................................................
Surgical Corrections. and Prognosis...................................................
Preliminary Impressions.........................................................................
Mandibular............................................................................................
Maxillary................................................................................................
Patients 'That Gag Easily........................................................................
Pouring Im~pressions ............................................................................
.................................................................................
Trimming of Casts Fabrication of Custom Impression Trays...............................................
Second Visit = Final Impressions.................................................................
Border Molding......................................................................................
Use of Impression Stick Compound...........................................................
Use of Heavy-Bodied Putty........................................................................
Border molding of Mandibular Tray............................................................
Final Mandibular Impression......................................................................
Border Molding of Maxillary Tray................................................................
Final Maxillary Impression.........................................................................
Boxing and Pouring..............................................................................
Separating Casts..................................................................................
Keying Casts..........................................................................................
Fabrication of Baseplates...........................................................................
Fabrication of Wax Occlusion Rims............................................................
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Page 2 Third Visit .Occlusal Plane. Vertical Dimension. Centric Relation.
Face-Bow Transfer. Mid.Line. Smile Line. and Selection of Teeth............ 57
Occlusal Plane............................................................................................. 58
60
Vertical Dimension...................................................................................... Face-Bow Transfer..................................................................................... 62
Centric Relation.......................................................................................... 67
Mounting the Maxillary Cast........................................................................ 69
70
Mounting the Mandibular Cast..................................................................... Selection of Anterior Tetth.......................................................................... 73
Porcelain or Resin................................................................................. 74
Shade Selection.................................................................................... 74
Mold Selection....................................................................................... 75
Ordering Teeth...................................................................................... 83
Selection of Posterior Teeth....................................................................... 84
Set-Up
Optional Visit: Arangement of Anterior Teeth ............................................ 86
Evaluation of Anterior Teeth........................................................................ 92
92
Re-Shaping of Teeth................................................................................... 92
Arrangement of Anterior Teeth If Nott Done As An Optional Visit ................ Arangement of Posterior Teeth.................................................................... 93
Fourth Visit Evauate Occlusal Plane. Centric Relation. Vertical Dimension
and Esthetics. Patient's Acceptance of Tooth Arrangement. Posterior
Palatal Seal. and Protrusive........................................................................... 96
Occlusal Plane.............................................................................................. 97
Vertical Dimension........................................................................................ 98
Centric Relation........................................................................................... 98
Correcting an Incorrect Mounting............................................................... 98
Esthetics........................................................................................................ 99
Protrusive Record.......................................................................................... 100
Posterior Palatal Seal................................................................................... 102
Festooning..................................................................................................... 105
Remount Record For Maxillary Denture........................................................ 112
Utilization of Commercial Laboratory............................................................. 112
Examination of dentures upon return from laboratory.................................... 114
Remount casts............................................................................................... 114
Care of dentures after polishing................................................................... 11
FifthVisit Insertion of Finished Dentures....................................................... 115
Centric Relation Record............................................................................... 117
119
Equilibrate Occlusion.................................................................................. InstructionsTo Patient................................................................................. 122
Adjustment Appointment............................................................................... 124
Discussion of results with your instructor............................................... 125
Post-Insertion Problems................................................................................. 126
Denture Adhesives.......................................................................................... 134
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Page 3 Immediate Dentures.......................................................................................
First Appointment: Preliminary Impressions................................................
Fabrication of Custom Impression Tray .................................................
Second Appointment: Final Impressions....................................................
Fabrication of Occlusion Rims................................................................
Third Appointment: Occlusal Plane. Vertical Dimension. Face.bow. C.R. Record. Selection of Teeth..................................................................... Cast Preparation and Arrangement of Anterior Teeth........................... Arrangement of Posterior Teeth and Wax-Up........................................ Fourth Appointment: Insertion of Dentures..................................................
Post-InsertionAdjustments......................................................................
Overdentures....................................................................................................
Advantages...................................................................................................
Disadvantages ..............................................................................................
. . Ind~cat~ons .....................................................................................................
Selection of Supporting Teeth.......................................................................
Procedures....................................................................................................
Insertion.........................................................................................................
Abutment Relines..........................................................................................
Reline and Rebase Technique.........................................................................
Use of Visco-Gel...........................................................................................
Procedure.....................................................................................................
Denture Repairs...............................................................................................
Fractured Dentures.......................................................................................
Replacing a Broken Tooth............................................................................
Border Molding with Adaptol and Vinyl Siloxane Putty...............................
ACKNOWLEDGMENTS
The authors are grateful for the help and suggestions of the Prosthodontic faculty, especially Drs.Phillip Reitz, John Sanders, and Larry Kaplan. Our sincere thanks to the Department of Audio-Visual Services, especially Mr. Martin Fong and his staff. To Mr. Carlos Serret and Mr. Udo Ahrndt a big thanks for their laboratory procedure advice for the construction of the trays, baseplates, etc. To Mr. Mark Greenridge of the Restorative Department for his help in the original typing of this manual. We are indebted to the Dentsply Co. for photographs and sketches, and the Teledyne Co. for sketches and write-ups on their articulator. We are indebted to Dr.Robert Lee and the Panadent Corp. for their permission to use their drawings and instructions on the use of their face-bow. A few comments from Dr. Levin: 'The first manual was written in 1966 and had
38 pages It described the procedures for complete and immediate dentures, and there were no illustrations. Later editions included relines and a some illustrations. In '72 we included a new concept (at 'that time), "Overdentures", and had 15 illustrations. The editions between '73 and '84 were mainly updating and gradually adding more line drawings. In '93 we added a detailed and illustrated section on arranging the anterior teeth and denture repairs. 'This 2002 edition has 174 pages and 76 illustrations, not counting mold charts, and patient treatment forms and handouts. New subjects are post-insertion problems and solutions. commur~icating with patients, putty border molding, and denture adhesives. Recommended References: Boucher's Prosthodontic Treatment For Edentulous Patients. Carl Boucher et al, 10th Edition. Classic and comprehensive. Impressions for Complete Dentures, B. Levin. Out of print but available from USC Book Store.
INTRODUCTION GOALS OF REMOVABLE PROSTHODONTICS: 1. The primary goal of the School of Dentistry is to prepare dental students to become restorative dentists capable of competer~llyperforming basic fundamental procedures of prevention and therapy in all phases of dentistry. 2. Dental students will learn to manage and treat the partially and fully edentulous patient so the patient is restored to a state of health, and the structures remaining will be esthetically and functionally sound, and according to current accepted treatment protocols.
Complete denture service contributes to the general health of the patient by restoring the gnathostomatic system in a functionally healthy and comfortable condition. The parts of this system, though considerably mutilated in the edentulous condition, nevertheless must be maintained in health and comfort. Surrounding this system is a whole patient with fears and apprehensions, and possibly with phobias, stuttering, poor speech, and malposed musculature, as well as many other tensions state. and concomitant disorders to which we are all prone even in the dent~~lous Therefore, in attempting the restoration of this system to a prosthodontic form of health it behooves us to know everything regarding the problem of the patient's health and general well-being, to the end that our efforts will prove successful. There must be mutual trust and understanding, and a rapport must be established between patient and doctor. It is important to like people and respond to reasonable demands and desires. While a well-executed dental restoration is the hallmark of a clinically sound procedure, this may be inadequate for a complete denture patient. Although a "mechanically perfect" denture prosthesis may be fabricated, the patient may not tolerate or adapt to it. The underlying problem may be physical or emotional. It is very important to involve the patient during the complete denture fabrication process, especially at those check points where his or her acceptance and comfort are essential. A viable dentist-patient interaction is thus a requisite to achieving successful results. It is also important to develop the knowledge and skill in all the mechanical and technical skills that are utilized in the treatment of the edentulous patient.
You cannot have the rapport and confidence of your patient if you are uncertain and fumbling. This manual is an important guide for your laboratory and clinical procedures and have it in your cubicle for each visit. Studv it well before atterr~pting any dental procedure! Much thought and effort has been expended to make your task easier. There are many acceptable methods of making dentures but you can imagine the confusion if all the methods were taught. It is our fond hope that you will either learn or even originate a better denture technique, but meanwhile we are confident that you will obtain excellent results with this basic technique. When unusual mouth or physchological conditions may necessitate a change from this basic method, your instructor will advise you how to proceed.
GENERAL POLICIES: 1. Most im~ortant:Patient treatment must be done with the highest levels of
professional conduct and should always be characterized by courtesy and
respect.
2. The school denture technique will be used for all cases, except in unusual situations and at the discretion of the instructor. Studv 'the clinic manual so we can standardize our procedures.
3. Students are reminded that 'the primary function of a dental school is the education of students. Patients that are difficult for various reasons will be
dismissed (faculty member only) at the diagnosis visit or later, if necessary.
4. All complete and irrtmediate dentures will be inserted in six weeks or less, except in cases of illness or any other valid situation. 5. An instructor will have the option not to supervise a student who does not have all his necessary instruments and materials available at the unit and this manual on the back bench and open for the appropriate visit. Precious time is wasted when a student has to rattle around histher cabinet or go elsewhere to find an instrument, or go to the dispensary for some required material.
6. An entry must be made in the clinical record for each appointment. It will be signed by the student and the instructor. It is the students responsibility to obtain the instructor's signature. Make certain the Therapy Record is recorded and signed by you and your instructor as this record will always remain in the file. 7. It is very important to collect 113 down, 1/3 after the trial denture, and the final payment before placement of the completed denture. You will find out that in
school (and in private practice) the fee is difficult, often impossible, to collect after the prosthesis has been inserted. 10. Make certain to make detailed notes of any unusual difficulties or recommendations on the treatment record. 11. The denture may be graded for final credit after the case has been in the mouth free of irritation for no less than one week.
ASSIGNMENT OF PATIENTS: Unfortunately, we never have too many denture patients since there are numerous other convenient sources of treatment in the Los Angeles area. We have had a very favorable experience with treatment for close farrrily members and friends. These people will often prefer to have your dental services later, so you would be doing them and yourself a favor by treatment here where you will have the benefit of advice and counsel. Students must share some of the responsibility and try to obtain suitable clinic patients. TYPES OF DENTURE SERVICE: Four types of denture services 1. Complete dentures 2. Immediate dentures 3. Overdentures 4. Implants (usually treated by graduate students but there is
an opportunity to participate, if interested)
DIAGNOSIS AND TREATMENT PLANNING: After receiving the patient's chart, and if the treatment is obviously a complete or immediate denture, an appointment is made for what we call an "informal" or "tentative diagnosis." Find out what days are best for future appointments. If possible, it is very important that you work with the same instructor for each removable prosthodontic case (complete dentures, immediate dentures, overdentures, and removable partial dentures). Working with one instructor will provide better continuity and fairer grading. Most of our patients with unsatisfactory results have been treated by students who made appointments at their convenience and used different instructors. This often ends up with a variance of opinions, a great loss of time, and often a remake. The first visit will tell you if your patient needs a denture, partial denture, overdenture or implant. Sometimes it's easy call but often an experienced dentist will want to ponder awhile. If time is limited you should at chat with your patient and get to know himher better, and make a cursory inspection of the ridges and oral structures. COMPLETE DENTURES: An exarrrination of the ridges and oral structures is needed to determined if the patient can be successfully treated by an undergraduate student. Usually high expectations that are not realistic or other psychological problems are the cause of most failures. Only instructors will determine if the patient is eligible for treatment here. Your Group Administrator will refer the patient to graduate Prosthodontics, outside dentist, or whatever would help the patient the most. You will soon observe that most ~atientsare verv treatable. IMMEDIATE DENTURE: An immediate denture is one that is fabricated before the teeth are extracted. Many patients prefer this as they are unwilling to be seen without teeth. The initial judgment of whether or not the treatment is an immediate by an instructor. Make certain that you and the patient are denture will be made aware of the fact that this is only a tentative diagnosis. Sometimes it is possible to make a much more satisfactory prosthesis, such as a removable partial denture, an overdenture, or even an implant, i.e., if the patient is willing to undergo extra treatment and expense. 5
If it is possible to change the treatment plan to a fixed or removable partial denture or an overdenture, a consultation will be needed with a designated "facilitator" from Fixed, Removable.or Implant Prosthodontics. A periodontal evaluation now is very important. For an obvious immediate denture, it is not necessary for the periodontal evaluation. If the final treatment plan is corr~pleteirr~mediatedentures, your instructor will make the proper notation on the treatment plan along with the estimated fee. Do not extract anv posterior teeth or do any procedure until an instructor has finalized the treatment plan. OVERDENTURES: In the past, periodontally weakened teeth were usually extracted. An overdenture is a complete denture that is fabricated over retained teeth. 'These teeth are treated with periodontics and endodontics, and then shortened. Patients who have been tentatively diagnosed for immediate corr~plete denture should be considered for this more satisfactory prosthesis. Teeth used for support should be teeth that have a crowniroot ratio so poor that the prognosis for a fixed or partial denture appliance is not possible. 'The patient must understand the risk of losing overdenture abutment teeth but the retention of these teeth is very advantageous. LENGTH OF TREATMENT TIME AND APPOINTMENTS: Denture patients usually have a history of indifference and neglect and is often the cause of the edentulous situation. However, once denture treatment has been started, the patient is usually very anxious to have the prosthesis. It is very discouraging when the treatment is extended too long. Once the treatment is started, you have a moral obligation to finish the case as quickly as possible. Whenever possible see the patient twice a week. There are few valid excuses for taking longer than six weeks to complete the denture. Block assignments are given well in advance and could delay treatment, so denture patients require special care when scheduling. Most of the denture procedures will require three hours in the morning or afternoon session. Do not waste precious time by scheduling a long visit for an adjustment, or other short procedures. Occasionally patients will not return for the final examination and grade. A final grade will be signed by the instructor only after the student has sent an appropriate letter to the patient and he/she still does not return.
CLINICAL REQUIREMENTS: As specified and will be posted. A good clinical experience would be: Complete denture ,2 sets or 4 singles combined with RPD, overdenture, etc.
Immediate denture, at least 1.
Overdenture, at least 1.
Removable partial denture, 4 (2 should be distal extension cases).
Treatment partial denture, at least 2.
Processed complete denture reline or rebase, at least 2.
Processed partial denture reline or rebase, 1.
Complete denture repair (add a tooth repair crack or add PPS, 1.
Partial denture repair (add a tooth or clasp), 1.
MISCELLANEOUS: 1.
Complete denture and denture reline insertions must be corr~pletedno later than one week prior to final examination week and two weeks for immediate dentures. This does not include adjustments.
2. Maxillary and mandibular relines (or rebases) must be done separately. This is necessary because of the possibility increasing the occlusal vertical dimension or losing the centric relation position.
3. Except for graduating seniors, the student who completed the denture will be responsible for all future adjustments, relines, and repairs. This is especially necessary for immediate denture patients. SPECIAL AWARDS: The Frank M. Lott Prosthodontics Award is given to the graduating senior who shows the most interest and proficiency in complete and removable partial dentures. The Bernard Levin Prosthodontics Award is given to the graduating senior who has shown the most interet in removable prosthodontics during his four year program.
OUTLINE OF CLINICAL COMPLETE DENTURE TECHNIQLIE:
1st Visit:
Lab:
2nd Visit:
Lab:
3rd Visit:
Lab:
Patient interview, review health history, clinical and radiographic examination, diagnosis and prognosis, and patient education Preliminary impressions with alginate Select teeth (optional) Pour impressions with yellow stone and trim casts Outline for custom tray Fabrication of custom tray Adjust tray borders Border mold Final impressions Select teeth (optional) Box impressions Pour impressions with vacuum-mixed yellow stone Trim and key casts Fabricate record bases with occlusion rims Adjust maxillary occlusion rim to correct lip level, parallel ala-tragus line and inter-pupillary line Measure physiologic rest position Evaluate previous dentures Adjust mandibular occlusion rim to a tentative O.V.D. Face-bow record Record centric relation at O.V.D. Select teeth Mount casts Complete set-up
Optional Visit: Arrange anterior teeth (recommended if good esthetics especially needed) Lab: Complete arrangement of posterior teeth
4th Visit:
Finalize Occlusal Vertical dimension: External measurements Phonetics Swallowing Facial appearance and comfort Prove centric relation Protrusive record - set condylar guidances Locate and carve posterior palatal seal Esthetic evaluation - patient approval most important
Lab:
Complete arrangement of teeth in balanced occlusion Complete wax-up Make plaster index for face-bow record Separate master casts from mountings Laboratory processing and polishing Make plaster remount casts Mount maxillary denture using plaster index
5th Visit:
Insert dentures Have patient bite on cotton rolls for at least 10 minutes Check adaptation with pressure disclosing paste Inter-occlusal centric relation record M o ~ ~mandibular nt denture Equilibrate occlusion Polish
Lab:
6th, 7th, etc. Visits: Adjustments and final evaluation Note: Appoint the patient at 9 a.m. or 1:30 p.m. so you have the entire morning or afternoon for each major appointment. This will allow you time for some of the lab procedures. This is especially necessary when making impressions or recording jaw relations. NOTE: Obtain the treatment form "Complete Denture Prosthesis Record". Sample on following page.
UNIVERSITY OF SOUTHERN CALIFORNIA SCHOOL OF DENTISTRY Complete Denture Prosthesis Record -
Student ..........................................................................No ...............................Patient .........................................................................................No ................................. .Assigned Instructor ......................................................... No ................................Type of Case .....................................................................
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Fee ..................................
(Do not shut step 2 w ~ b uan t assigned instructor)
Remarks: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - .>
NOTE: All clinical and laboratory procedures
must be signed by an instructor. ALL procedures marked with an asterisk (*) must be
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signed. by your assigned instructor.
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Procedure Sequence
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Grade (circle)
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1. Initial Interview *2. Diagnosis and prognosis "3. Prelimary impression-max *4. Preliminary impression-man 5. Preliminary cast(s) trimmed
with outline for tray(s)
6. Custom tray(s) fabricated 7. Border molded tray - max
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Initials
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Date
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Insuuctor's Comments
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4 3 2 1
4 3 2 1
4 3 2 1
1 4 3 2 1 Final impression - max Final impression - man 1 4 3 2 1 Master cast(s) trimmed & indexed I Record base(sl with occlusion I
r i d s ) fabricated 1 3. Occlusal plane 14. Face-bow * 15. Occlusal vertical dimension 4'32 1 4 3 2 1 * 16. Centric relation recorded 17. Teeth selected 18. Anterior tooth arrangement 1 9. Posterior tooth arrangement 4 3 3 1 *20. Examination of trial denture(s) in mouth 7 1. Protrusive record 22. Articulator set 23. Posterior palatal seal 24. Final set-up and wax-up 25. Laboratory remount 26. Denture(s) polished "27. Placement: tissue adaotation 1 4 3 2 1 remount, occlusal equiiibration 28. 24 hr ~ o s t la cement tissue
adaptahon and articulation check
ADJUSTMENTS:
*9. * 10. I I. 12.
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*29. Final adaptation. polish and articulation check 30. Reline (if indicated)
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4 3 2 1
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1
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I approve of the color, shape and arrangement of the teeth
in wax dentures.
(Patient's signature and Date)
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FIRST VISIT
DIAGNOSIS, PROGNOSIS, AND PRELIMINARY IMPRESSIONS Materials Needed: I. Edentulous trays 7. Vaseline 8. Alginate impression material 2. Rubber bowl - large 3. Plaster spatula 9. Water measure 4. Mouthwash 10. Periphery wax 5. 2 x 2 gauze 11. Sharp knife 6. Mouth mirror 12. Indelible pencil 13. Periphery wax NOTE: This manual must be open for reference and available for
every clinic visit.
DIAGNOSIS AND PROGNOSIS: I. Review the general health history from the initial examination. 2. Younger patients usually have better health, neurorr~uscularcontrol and adaptive capacity, and therefore have a more favorable prognosis. 3. Men are usually better patients as they are occupied with their work and their have less time to fret about their dentures. Women tend to scr~~tinize dentures and are more particular about esthetics. Nearly always, the most difficult patients are the pre-menopausal and post-menopausal women as they often have psychological problems and symptoms such as dry mouth, burning sensations, loquacious, vague pains, etc. 4. Stressful employment often complicates the adjustment to wearing dentures (example - bruxing).
EXAMINATION OF PATIENT:
Most students (and dentists!) are anxious to get started, i.e., take impressions.
However, a thoughtful diagnosis and prognosis are essential for success.
Review all of the following: it will take about 15-20 min. but will be time well spent.
Experienced dentists can do this in 4-5min. Note any unfavorable factors and
record on the denture record.
Read ~ a a e s20-22 on Patient Communication before ~roceedina. -.
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1. EDENTULOUS HISTORY RECORD: Record the age of the present dentures,
the number of previous dentures, success of previous denture, and the nature of complaints. The length of time edentulous (years) and previous dentures (number) should be correlated. For example, if the patient has been edentulous for 20 years with no previous denture, the prognosis is poor. If this same patient had 1 or 2 previous dentures and they were satisfactory, the prognosis is good. If this same patient had 5 or more sets of dentures, the prognosis is poor. If a patient had partial dentures, inquire if they were satisfactory or not. If there were problems, or if the partial dentures were not utilized, make certain to record this. We cannot over err^ pliasize the importance of obtaining a detailed account of the previous denture history, especially if there were problems. IMPORTANT: It is very advantageous to make alginate impressions of both dentures ((external surfaces and teeth), make stone casts as these will be an exact copy of the original dentures. This especially useful if the patient was satisfied with the dentures. They are very useful for tooth selection, tooth arrangements, arch form, etc. They are very convenient when fabricating the wax occlusior~rims. Your lab technician (when in private practice) will greatly appreciate these valuable guides. 2 RESIDUAL RIDGE: A square arch is the most favorable for retention and stability. The ovoid arch is slightly less favorable and 'the tapering arch is the least favorable. A broad ridge is the most favorable. Irregular ridges with undercuts or sharp projections may require surgical correction. A flat lower ridge is usually difficult but can be managed if the patient has a favorable tongue position and a wide buccal shelf. The most difficult ridge is thin and knife-edged, especially the mandibular. This is usually seen in a tapered arch with sharp mylohyoid ridges and narrow buccal shelves.
3. RESIDUAL RIDGE RELATIONSHIP: Class II or retrogna'thic is usually difficult as the patient looks toothy, often holds the mandible forward to improve appearance with subsequent TMJ problems, usually have a great range of jaw movements in function, require careful occlusion, and usually needs a large interocclusal distance. Class Ill or prognathic is usually easier if not extreme. The patient usually functions on a hinge (little or no protrusive component) and requires a minimum of interocclusal distance. In any case, do not set the teeth
for a retrognathic or prognathic patient in a normal relationship, unless there is only a moderate deviation from Class I.
4 PALATAL VAULT FORM: A flat palate has good vertical support but provides
little resistance to lateral shifts. A high (or "V-shaped") palate resists lateral shifts well, but vertical displacement tends to break the seal in all areas at once. Gagging is more common and processing shrinkage is greater. Fortunately, this vault form is uncommon. A curved or "U-shaped" palate provides the most favorable prognosis and resists both vertical and lateral displacement. 5 TOR US PALATINUS: Does not require surgical intervention unless large and bulbous. Even in this case, a roofless denture can be made if the ridge is good and the patient has reasonable coordination. The mucosa over a torus is usually thin and unyielding. Arbitrary relief (often used in past years) is not used. The correct relief is obtained by the use of pressure indicator paste in the finished denture. 6. MANDIBULAR TORUS: Usually more of a problem as it interferes with 'the lingual border seal and a denture would restrict the tongue space. Surgical correction is indicated if prominent and especially if undercut.
7. AVAILABLE POSTERIOR PALATAL SEAL AREA: A wider and deeper posterior palatal seal area is more favorable for retention. The posterior palatal areas were described and classified by M. M. House. JUNCIWN OF HARD AND SOFF P W
CLASS l
CLASS Ill
7
Class I : Large and normal in form with soft tissue extending posteriorly from the hard palate for 5-12 rnm., at which point the curtain of the soft palate. becomes movable (called the "ah" line) with a decidedly large range of movement. Class II: Medium and normal in form, having movable tissue approximately 3-5 mm. posterior to the hard palate. Class Ill: Small and with little or no movable tissue posterior to the hard palate, with the soft palate turning down abruptly within 1 mm. of the junction of the hard and soft palates. Class I offers the largest area for the palatal seal and Class II somewhat less; both are favorable as the posterior seal can be placed in soft tissue. Class Ill has little movable soft tissue posterior to the hard palate and it is not possible to place a conventional posterior seal. In this case, a posterior double bead is the seal of choice. The most common palate form is the Class 11.
8 GAG REFLEX: Evaluated by lightly running a mouth mirror over the soft palate. A slight or no response is most favorable. Moderate gagging can usually be controlled by careful denture procedures, counseling and even medication. Severe gaggers have a poor prognosis and should be evaluated carefully as they usually cannot be treated by an under-graduate student. 9. BORDER TISSUE ATTACHMENTS: A low position (away from crest) is most favorable for developing and maintaining a good border seal. High membranous and muscle attachments (near the crest of the ridge) are less favorable. Surgical corrections are possible but difficult as scarring and re-attachment can occur. Frenum attachments are only significant if high (w - t S~~urgical correction of frenums are not difficult.
SOFT TISSUES: Normal tissue is about 2 mm. thick, evenly distributed over the ridge and has normal color and appearance. Hard (thin and unyielding) tissue is usually seen in geriatric patients and presents problems with retention and soreness. Soft spongy tissue (gingival hyperplasia) is most often seen in the maxillary anterior area, especially when the patient had a maxillary denture and mandibular natural anterior teeth. This tissue can be surgically removed but the result is an anterior ridge with little or no vestibule. A surgical procedure is possible to deepen the vestibule but must be done as a graduate procedure. Inflamed soft tissue (denture stomatitis) requires caref~llconsideration as it may be due to ill-fitting dentures, excessive vertical dimension, bruxing, allergies, etc., or systemic conditions. Papillary hyperplasia is often seen when a patient has an ill-fitting maxillary denture or rarely removes the denture for cleaning or tissue rest. NOTE: If the patient has any of the above, discuss this with your instructor and obtain a consultation in Oral Surgery.
11. TONGUE POSITION: This is a very important consideration that has been largely neglected, and is of great interest to prosthodontists. To evaluate, instruct the patient to open just enough for a small portion of food and observe the tongue carefully. In the normal position, the tongue is relaxed, completely fills the mandibular arch, and the apex lightly contacts the lingual of the mandibular teeth. This position is most favorable for maintaining the lingual border seal and retention. In some you can see the patient holding the denture down with the tongue. The patient with a retruded tongue will have a poor lingual seal andusually has a poor mandibular denture prognosis unless this condition is improved. The simplest treatment is to tack on a small bit of self-curing resin on the anterior lingual flange, a few mm apical and lingual to the mandibular central incisors, using the old denture. The patient is asked to keep histher tongue in contact with the resin, except when eating and speaking. If or when the retruded tongue position improves (usually 2-3 weeks), the raised resin area is easily removed and polished. It is an easy procedure and worth trying when indicated. Most patients are surprised and pleased with the improvement. 12 FUNCTIONAL MOBILITY OF FLOOR OF MOUTH: A very important diagnostic aid and not difficult to determine. If the floor of the mouth remains at about the same level during swallowing, denture seal is usually easier to obtain, and conversely more difficult to obtain if the movement is large. The easiest procedure is to observe or palpate the hyoid bone during a swallowing movement and the amount of movement is easily observed. Also palpate the floor of the mouth to evaluate it's displaceability. Some are quite soft and others feel quite taunt. This will be one of the deterruining factors of the length of the lingual borders.
The posterior lingual area is called the retromylohyoid fossa and is an area important for stability and peripheral seal (see below). The retromylohyoid fossa (lateral throat form) depth and width in moderate function is estimated by placing a mouth mirror (which is about as thick as a denture) in the disto-lingual vestibule. This has been classified by Ewell Neil : Class I The mouth mirror is not visible when the tongue is in a slightly protruded position; most favorable for retention and stability. Class II One half of the mouth mirror is visible; less favorable. Class Ill 'The entire mouth mirror is visible; least favorable.
ANATOMY OF DISTO-LINGUAL VESTIBULE 1. Mylohyoid muscle -
2. Palatoglossus muscle
3. Superior constrictor muscle 4 Pterygomandibular raphe
5. Buccinator muscle
13. CHARACTER OF SAI-IVA: Normal amount and viscosity is the most favorable.
Thin watery saliva is best in theory but a mix that includes some viscous saliva will provide the best retention. Thick ropy saliva corr~plicatesimpression taking and is annoying to the patient as it clings to the denture.
14. AMOUNT OF SALIVA: Excessive saliva is common when the denture is first inserted but usually improves in time. Deficient saliva (xerostomia) is often seen in geriatric patients who have certain systemic disorders and are taking medications, and resl-]Itsin a poor prognosis for denture retention and comfort. No saliva is the most serious problem and is usually the result of radiation for oral cancer. This patient would require special care and should be treated in Graduate Prosthodontics. 15. PROMINENCE OF MAXILLARY AN'TERIOR RIDGE: If the maxillary anterior ridge is prominent and undercut, a decision must be made whether to use a "flangeless" or short flange denture, or if an alveoplasty is best. This decision is often necessary for immediate dentures. 16 RADIOGRAPHIC: Examine the radiograms carefully and note any
abnormalities. Retained roots with no apparent pathology can often be left alone provided the patient is informed of their presence and x-rayed periodically. 17. ATTITUDE OF PATIENT: A simple and practical classification has been described by M. M. House:
Class I : Philosophical
a. Those who have presented themselves prior to the extraction of their teeth, have no experience in wearing artificial dentures and do not anticipate any special difficulties in that regard. b. Those who have worn satisfactory dentures, are in good health, are a wellbalanced type, and are in need of further denture service.
Class 2: Exacting
a. Those who, while suffering ill health, are seriously concerned about the appearance and efficiency of artiaficialdentures. They are, therefore, reluctant to accept the advice of the physician and the dentist and are unwilling to submit to the removal of their natural teeth. b. Those wearing arti'ficial dentures unsatisfactory in appearance and usefulness, and who so doubt the ability of the operator to render a service which will be satisfactory that they often insist on a written guarantee or expect the dentist to make repeated attempts to please them.
Class 3: Hysterical a. Those in bad health with long neglected pathological mouth conditions, and who dread dental service and submit to the removal of their teeth as a last resort and who are positive in their minds that they can never wear artificial dentures. b. Those who have attempted to wear artificial dentures but failed and are thoroughly discouraged. They are of a hysterical, nervous, very exacting temperament and will demand efficiency and appearance from *the artificial denture equal to that of the most perfect natural teeth. Class 4: Indifferent Those who are unconcerned about their appearance and feel very little or no necessity for teeth for mastication. 'They are therefore nonpersevering, and will inconvenience themselves very little, if at all, to become accustomed to dentures. Class I and II patients are nearly always treatable, even with poor ridges and other oral handicaps, and Class Ill and IVs are usually 'the most difficult. PROGNOSIS: It is often difficult to make a correct prognosis, even for an experienced dentist. If the patient has any of .the negative factors described (poor ridges, flabby tissue, etc.) that can be a barrier to successful dentures, these must be pointed out and.explained NOW. If they are pointed out after the dentures are com~leted,you will sound like you are making excuses. The limitation of dentures must be pointed out (limited mastication, not a face lift, etc.).
COMMUNICATING WITH PATIENTS: The ability to communicate effectively and explain the problems of wearing dentures is undoubtedly one of the primary factors for successful treatment. You can be sure you are going to have this type of patient in your chair and you RE SO GOOD, better have some straight answers.
Often the problem is with a patients with poor ridges, poor coordination, etc., but they don't want to hear that. 'They will say you made a set for their aunt Tillie and she says they are perfect! "You can do the same (a denture is a denture, ain't it ?)". Now is the time to educate the patient to the fact that every mouth is different.
These patients have realistic concerns and need to know why are they having problems and what can be done about them.
Now comes the difficult part: communication. It is necessary to explain what causes these problems and what can be done or what can't be done. The art and science of communication have become very important and large corporations will pay millions to "connect" with their clients. We aren't in their position but we can "connect" by using some old fashioned common sense. 1.
Talk about the problem and possible solution in layman terms. Avoid words as vertical dimension, centric occlusion, etc. Talk about the height of the face, the way the teeth come together, etc. --
2. Use analogies as much as possible. The cartoon is good but the caption is bad. Talk about a wide, rounded jaw, a thin, sharp edged jaw, or a flat jaw. Explain there is a big difference between sitting on a large log or a narrow plank. Save some old casts that have the different ridge forms so the patient can see and even feel the difference.
8 DEUTURE REST lNC bU CI BROBD eRsE OR RI'IME WILL 8 E moRC COmFORT+3BLE TUAlJ ONE RESTIN6 O N fi Sfl6Rp SPINY RIDGE.
..Or( fl
FIIIT ONE
.h/
3. Explain that new and better fitting dentures may help many problems.. Misery loves company! a~~ Inform the patient there are about 25 million UP TOO denture wearers, according to government statistics, and most are satisfied! E APl LY A soup diet is unnecessary, especially if the patient can learn to chew on both sides at once. The most difficult part is that some patients need a lot of time to get used to these clumsy objects!
,,,,
/.
/
21
BOTH SIDES A T ONCE
4. If the patient has an obvious reduced
vertical dimension there is a need to explain that natural teeth gradually wear down and the chin will move closer to the nose. 'This will occur faster if the patient has been wearing dentures for a long time. The result is a bunching - of the skin in the lower face with resultant wrinkles and depressions.
A 4 mm layer of Bosworth green wax on the
lower occlusal surfaces and some on the
buccal flanges takes but a few minutes but
provides a preview of how this problem can
be improved. Don't forget to mention that
complete elimination of wrinkles by this is not possible. {Give the patient a Copy of this illustration and explanation).
Natural, normal expression with natural teeth or with artificial dentures when first inserted in the mouth.
~ffectof wearing the same artificial dentures for too long a period. Wrinkles or depressions form in the Upper and lower lips ( A and C). The lips become compressed and protrude ( B ) . The chin moves forward and upward and becomes pointed ( D ) . ~h~ cupid's bow loses i t s shape and the lipline straightens ( E ) . Pouches become pronounced on each side of (ADA illustrations) the lower jaw ( F ) .
5. Don't lecture to your patient. Make your comments short and to the point. Be upbeat and never pessimistic. There is a strong basic need, inherent to most, to be liked. The eminent prosthodontist Bernard Jankelson has stated, "If the patient likes you, heishe will like the dentures. If the patient don't like you, the dentures will always be faulty."
Recommended Reading:
"Commurrication In Our Lives", Julie T. Wood, Wadsworth Pub.., basic text used by the
USC Annenberg School of Communication.
"How To Win Friends and Influence People", Pocket Books, lnc., '36, $12.95 in USC
bookstore. One of the most popular (16 million copies) and important books written on
self-improvement and practical communication.
SURGICAL CORRECTIONS - An assessment of needed surgical correction is made before the final prognosis. 1. Muscle attachments that are close to the crest of the ridge are unfavorable to denture stability and retention. Surgical correction in this case is relatively difficult and is usually not done except in extreme cases. 2. Large tuberosities provide good support and retention; however, they must be viewed with suspicion. If deep, bilateral undercuts are present, they should be corrected with surgery. Extremely long tuberosities that can interfere with the mandibular denture can be reduced. Flexible, fibrous areas overlaying tuberosities effect stability and ideally should be surgically excised. 3. Sharp and/or prominent mylohyoid ridges will make it difficult to create a seal in the disto-lingual vestibules. 'This area is especially irr~portantwhen the ridge is poor but the patient has a Class I or II lateral throat form. A sharp mylohyoid ridge is also a potential source of soreness during mastication. Surgical correction is not a difficult procedure. 3. Abnormal soft tissue, usually seen in the upper anterior area, especially if it is a large mass and pendulous, can be easily corrected. IMPORTANT: There are alwavs potential surgical risks. Make certain there are no medical contra-indications or psychological problems before you get into a discussion with your instructor and patient in this matter.
It is estimated that any competent dentist satisfy about 70% of the denture wearing patients, 25% can be treated by the experts, while the remaining 5% cannot be successfully treated. If your instructor believes the patient cannot be treated by an under-graduate student, refer the patient to your Group Administrator for referral to Graduate Prosthodonticsor ifthey are not able to accept the patient, to the L.A. Dental Society for a list of qualified prosthodontists.
Objective: To make an overextended impression of the ridges, vestibules, and underlying bony supporting tissues so properly extended custom impression trays may be constructed. Note: If is impossible to make a correct final impression unless the preliminary impression is properly extended and tray borders are correct. 1.
Positioning of the patient: The patient should be seated comfortably in an l~prightposition. The ridges should be parallel to the floor, so position -the head rest accordingly.
2. Lubricate the patient's lips lightly with Vaseline. 3.
It is usually best to complete the mandibular impression first. This accustoms the patient to the material, there is less apprehension and may prevent or lessen gagging when making the maxillary impression.
MANDIBULAR PRELIMINARY IMPRESSION: 1.
Mark the distal ends of the pear-shaped pads with a disposable indelible stick. The pear-shaped pads are usually pale, firm, attached, and stippled. The retromolar pads are redder, soft, and not attached or stippled. Ask for help f you cannot locate the end of the pear-shaped pad and 'the beginning of the retromolar pad.
2. Select a tray that extends slightly distal to the marks and has about 5 mm. between the trays and tissue. For the average ridge, use edentulous trays. For a large ridge, it may be an advantage to use dentulous trays.
3.
Extend the tray with red utility wax, if indicated. Roi~tinelvplace soft periphery wax on the entire lingual border. This wax requires little or no heating. The wax is not used to extend the tray, but is needed to help displace the tongue and floor of the mouth, and force alginate into the entire lingual vestibule. Seat the tray firrr~lyto adapt the wax. 'Then dry the wax with an air syringe and add a thin layer of alginate adhesive (Hold).
24
4.
lnstruct the patient to rinse vigorously with a mouth wash to remove ropy saliva and possible debris from the mouth; remove with an oral evacuator.
5. Use about 700 water; a few degrees warmer or colder for less or more working time. About 15% less water is used to obtain a thicker mix; this will displace the soft tissues and provide better extensions.
6. Mixing time depends on the brand of alginate. Mix the alginate for 1 minute for Jeltrate or 30 seconds for Coe. The mix must be smooth and creamy. 7.
Load the tray so the alginate is evenly distributed and 'completely fills the tray. Load the tray in one minute or less. Don't smooth the surface of the alginate; it's not necessary.
9. A normal amount of saliva will not effect this type of impression as fine detail is not necessary; it's usually not necessary to dry the mouth. If salivation is profuse, pack sponges over the ridge and remove just before seating the tray. 10. SEATING OF TRAY: Stand in front and to the right of the patient. If you are left-handed, reverse these hand positions. Retract the right corner of the mouth with your index finger of your left hand, or use a mouth mirror if the mouth opening is small. Seat the tray with your right hand rotating the tray against the left corner of the mouth. lnstruct tlie patient to raise the tongue as the irr~ pression is being seated in place (practice with an empty tray). Retract the lips and cheeks and make certain that the alginate is flowing into the vestibule and over the edges of the tray. When the tray is seated, release the lip. lnstruct the patient to bring the tongue forward and from side to side so the tip is approximately touching the lingual border of the lip. Hold the tray with your index fingers on the bicuspid region and your thumbs along the inferior border of the mandible. Im~ortant:'The preliminary irr~pressionmust also be border molded. Hold without movement for about 1 minute and then manipulate the lips and cheeks so the impression will have better extensions. The tongue movement (above) will also mold the lingual borders. This will make the procedure of outlirling the custom tray rnuch easier and more accurate. Break the seal by reflecting the' lip and remove with a jerk.
11. INSPECTION AND INTERPRtrATlON OF DEFECl'IONS: a. Incomplete coverage 1. Tray too small. 2. Tray not corrected with wax. 3. Insufficient alginate used. b. Metal tray showing: 1. Too much pressure used. 2. Tray too large or too small (metal sticking into the lower slopes of the ridges). 3. Voids (usually in the lingual flange area) - the tongue was probably trapped under the lingual flange due to failure to have the tongue elevated when positioning the tray. c. Multiple small bubbles in the alginate: failure to mix 'the alginate thoroughly. The spatula must be forced through the alginate against the side of the bowl. d. Grainy appearance: 1. Failure to mix the alginate for a long enough. 2. Improper water-powder ration. 3. Water too hot. 12. Handling the impression after removal from the mouth: Wash the acceptable alginate impression with tap water (never use hot or cold water as dimensional changes will occur). If thick ropy saliva adheres to the impression, wash with a solution of plaster and water. Trim any excess alginate with a sharp knife or scissors. Dry the impression by shaking and blotting. Do not use an air syringe. 13. Now is a good time to make the outline for the custom impression tray, using an indelible stick. The outline is made 1-2mm short of the vestibules and must include the pear-shaped pads. If doing this for the first time, have an instructor make the outline. The indelible stick will transfer to the stone cast. Immediately wrap the impression in a wet paper towel. Pour no later than 12 minutes.
1.
Palpate for the pterygo-maxillary notches with a mouth mirror, and mark this area on both sides with an indelible stick. Ask the patient to say "ah". Note the "ah" (vibrating line) and mark this line with the indelible stick, connecting the hamular notches. To facilitate these marks, dry the mucosa with a 2 X 2 sponge and wet the tip of the stick with alcohol. Bear in mind that the vibrating line is not the junction of the hard and soft palate (except a House Class Ill).
2.
Select a tray slightly past the posterior line and allows a space of about 5 mm. between the tray and tissue.
3 . It is commonly recommended to bead the posterior border with periphery wax. This is not necessary unless the patient is a gagger. If the vault is deep, build up some support with the soft periphery wax to help prevent sagging of the alginate. Seat the tray 'firmly so the wax corrections are well adapted. It is an advantage to practice placing the tray and removing it. Always use the same path of insertion and removal. This also prepares the patient for the impression.
7. For your first case, have an instructor check the tray selection and wax corrections.
8. Mixing the alginate: The rubber bowl must be clean and dry. Use 10% less 70" water (use 72" or higher if the patient is a gagger). Mix to a smooth creamy consistency; 30 seconds to 1 minute, depending on choice of alginate.
9. Load the tray in one minute or less. 10. If the vault is high, place some excess alginate in 'the center of the palate with your finger to prevent trapping air. If the areas lateral to the tuberosities are large and deep, place some alginate in these areas.
11. Seating the impression: Stand to the right and slightly behind the patient (if you are left-handed reverse the standing and hand positions). Retract the left corner of the mouth with your left hand or use a mouth mirror if the patient has a small mouth. Retract the lip with an index finger and thumb and seat the tray into the labial vestibule. Then bring the back end of the tray up slowly so the alginate is flowing toward the distal. Stop seating the tray when you can see some alginate along the entire distal tray border. If the tray is overloaded and excess alginate flows onto the soft palate, remove the excess with a fast swipe of your index finger or a mouth mirror. 12. Border molding: Hold the tray without movement for a minute or until initial gelation, and border mold with manipulations of the lips and cheeks. Repeat these manipulations twice. 13. Break the border seal by raising the lip and remove the impression. Inspect
for defects and especially for identification of anatomical landmarks and correct extensions. 14. Outline for the custom impression tray with an indelible stick. 'The outline is placed about 1-2mm from the depth of the vestibules and Imm past the vibrating line and hamular notches. TIPS ON HANDLING PATIENTS THAT GAG EASILY: 1. Make certain to place periphery wax across the posterior border and make certain the wax posterior seal is firmly adapted.
2. Use 72" or warmer water so the alginate sets faster; you must work quickly. Seat the tray with alginate in the posterior area first rather firmly so no alginate will escape in that direction. Rotate the front end the tray up slowly and raise the lip so the alginate flow toward the anterior and will end in the labial vestibule. If some alginate flows past the posterior border, remove it with a quick swipe of your index finger or a mouth mirror.
3. Gaggers often salivate excessively so make sure the head is upright or slightly forward. Use a saliva ejector and also give the patient a few paper towels to catch any saliva that runs out. For a severe gagger, shake some table salt on the tip of the tongue just before seating the tray; a distraction device that is often effective, but don't let the patient see you using the ordinary salt shaker. 4. Constant talking and re-assurance are very helpful. Urge the patient to breathe slowly and deeply through the nose. Don't ever use the word "gag" as the word itself is often enough to initiate the reflex.
5. Remove the impression about one minute after gelation; don't wait the usual
three minutes.
HANDLING OF IMPRESSIONS AFTER REMOVAL FROM MOUTH: 1.
Rinse the impressions with tepid tap water; don't use hot or cold water as you can get dimensional changes.
2. If sticky mucin is present (common on maxillary), rinse the alginate with a solution of plaster and water.
3. Trim any excess alginate with a sharp knife or a pair of scissors. 4.
The irr~pressionsmust be poured within 12 minutes. Wrap one impression with a wet paper towel while doing the other.
POUR IMPRESSIONS IN STONE:
MAXILLARY: 1.
Dry the alginate impression by shaking and blotting; do not dehydrate. It is not necessary to box tl- is irr~pression.
2. Mix the stone to a heavy consistency using a technique to minimize air bubbles Hold the impression against the vibrator with one hand tipping it toward the
anterior. Place a small amount of stone on one posterior end and allow the stone to flow around to the other side.
3. Place a mound of stone that is at least 12 mm. thick and about 6 mm. wider than the impression. This base must have a heavy consistency or it will not support the weight of the tray. Invert the filled impression tray on this stone base. Center it carefully and jiggle it a little to avoid trapping air. Make certain the base of the impression tray is parallel with the table top. Work the stone along the borders to make it extend about 6 mm. beyond the impression and level with the borders. Make certain to reniove all stone that over the metal tray. It is difficult to remove a tray that is "locked in" with stone, often resulting in broken casts. MANDIBULAR: 1.
Same procedures as above except make certain the lingual land area is smooth and 'l'lat, and level with the lingual alginate border. It is very difficult to separate the impression if the lingual border of the tray (or any border) is locked with stone.
2. The impression and stone cast are covered with a wet paper towel to prevent drying of the alginate.
3. Allow the stone to set for 20 rr~inutesuntil the heat has been dissipated. Separate the impression tray from the cast in thirty rr~inutesor not more than one hour. Never keep the stone cast in water afterwards as artificial stone is soluble in tap water. IMPORTANT: Don't "bury" the impression trays in a mass of stone as it results in
an excessive amount of time and energy to separate and trim.
FINAL TRIMMING OF CASTS: 1.
Trim the excess stone with the model trimmer. The usual land areas are not needed. The cast is trimmed to the depth of the vestibules. The only land areas are posterior to the ridges and are 4-5mm wide. 'The lingual land area is
level with the depth of the lingual vestibules. 'The land areas have no height so as to facilitate the fabrication of the custom trays.
2. The mandibular base should be a full base and not the "U" shaped cast used for fixed restorations. The bases should be about 13mm thick, at thinnest area.
3.
Small excesses of stone from air bubbles can be flicked off. Try not to mar or scratch the ridge surfaces.
FABRICATION OF THE CUSTOM IMPRESSION TRAYS: Objective: To fabricate individualized final impression trays as an aid to correct coverage of the ridge, development of the border seal, and even distribution of the final impression material. Materials Needed: 1. Tray resin 2. Vaseline 3. Plaster spatula 4. Paper mixing cup 5. Lead pencil 6. Sharp knife
7. 8. 9. 10. 11. 12.
Arbor band and chuck Carbide resin bur Rag wheel on a spiral chuck Wet pumice Mounted handpiece Rolletteboardandroller
Note: The custom tray must be RIGID. It must have a handle that does not interfere with the tongue and lips and can be grasped securely. A handle that is too large or long is clumsy to use and uncomfortable for the patient. 1.
'The tray outline will either be present if placed with the indelible stick in the alginate impression or it can be drawn on the cast with a pencil. The tray outline is a very critical step and should be seen by an instructor. a. About 2 mm. short of the vestibule and frenulae.. b. To the distal aspect of the pear-shaped pad. c. I mm. distal to the upper posterior border.
2.
Block out any undercuts with pink baseplate wax. Do not over-block as the borders of the tray will be too far from the vestibules for correct border molding. Im~ortant:If the ridge is thin, most often the lower, make certain to flow pink baseplate wax along the sides of the thin areas. If not done, the thin part of the ridge will break when separating 'the final irrlpression from the master cast.
3. Lubricate the cast (ridge, vestibule depth, and land areas) with Vaseline. 4.
Mix the self-curing tray resin in a paper cup, following the manufacturer's directions for measuring the amount of liquid and powder.
5. Wait until the resin reaches a putty-like consistency. 6. Mandibular tray: Lightly Vaseline your fingers and the Rollette board and roller. Mold the resin into the shape of a "hot dog". Place it on the thick side of the Rollette board and roll out to a uniform thickness. Adapt the wafer over the cast with your fingers. To prevent thin areas, do not press too hard. Remove the excess material with a sharp knife or scissors. Keep adapting by quickly moving your fingertips over the entire tray area until initial polymerization takes place (rise in temperature).
7. Make a small mix for a handle. The handle should take the place of the centrals and laterals in length and width (see drawing above). The anterior handle should be no lonaer than 10-12 mm. 'The length of the handle measures 25 mm. from the edge of the labial border to 'the top. The width should be about 12 mm. - no more. A handle made this way will enable you to securely grasp the tray and it will not interfere with the tongue and lips.
Wet the anterior tray area with monomer so the handle will be securely attached. The handle must be finger supported until almost hard. Wait until the resin is hard and cool (about 15 to 20 minutes) before removing the cast.
8. Maxillary tray: The procedures are similar to above except the resin is formed to the shape of a flat ball before rolling out on the board. Roll out the wafer (begin from center and roll to the sides) so it is the approximate shape of the cast. The handle should have the same length of 25 mm from the edge of the labial border to the top and the other stated dimensions.
9. Trimming the trays: The gross excesses are removed with an arbor band and then perfected with resin burs in a handpiece. Polish the top and sides with pumice. The tray borders must be 2 rrlm thick (no thinner), rounded, and smooth. NOTE: ALL LABORATORY WORK USED IN THE MOUTH SHOULD BE NEAT AND CLEAN AND SHOULD REFLECT THE OPERATOR'S SKILL AND ABILITY. THIS IS VERY NECESSARY FOR THE PATIENT'S COMFORT AND WILL GAIN CONFIDENCE FOR ALL FUTURE PROCEDURES.
FINAL IMPRESSIONS Materials Needed: 1. Mouth mirror 2. Pan with cold water 3. Compound heater 4. Stick compound 5. Alcohol torch 6. Vaseline 7. 2 x 2 sponges Note: -
8. 9.
10. 11. 12. 13. 14.
3/32 twist drill or No.8 round bur Melite resin bur Light-bodied rubber base Mixing pad and spatula Indelible stick Sham knife Ceramic tile or glass slab
The denture manual must be open for reference.
If possible, the old dentures should be left out of the mouth 24 hours before the final impression. Unfortunately, many patients will not heed this request. If the patient has large areas of inflamed or distorted mucosa, the use of tissue conditioning, a special soft lining that is placed in the old dentures, may be indicated. Using tissue conditioning is an excellent procedure but increases time and costs. Discuss with an instructor if the mucosa is inflamed and requires either tissue conditioning or leaving the dentures out for a specified time. BORDER MOLDING
-
GENERAL INFORMATION:
Objective: To obtain a peripheral seal for good retention and proper extensions for good support. Ideally, the impression borders should be similar in thickness and length to the final denture borders. 'The borders of the custom impression trays are border molded until the tray has an adequate peripheral seal. This step is absolutely necessary for dependable and consistent results. Waxes, self-curing resin, heavy-bodied thiokol rubber, and various elastic materials have been successfully used for border molding. Stick compound takes a little more time and experience, but is an excellent material for students and the material of choice by many prosthodontists.
The patient should be seated in a comfortable position. The jaws should be parallel with the floorso the chair should be almost upright for the maxillary impression and somewhat reclined for the mandibular impression. The border molding is done in sections by using certain patient movements, manually manipulating the lips and cheeks, or a combination of both. There is no research or clinical data to state that superior results are obtained if done with patient movements (called the functional or physiologic method) or manually manipulating the lips and cheeks. The more cooperative patient can functionally mold the borders well under proper supervision. Other patients cannot follow directions easily and manipulation of the lips and cheeks by the dentist is necessary. 'The choice depends on the dentist. INSTRUCTIONS ON THE USE OF IMPRESSION STICK COMPOUND: 1.
When heating the compound over a 'flame, soften only the very end. Iftoo large an area is softened, the whole stick starts to sag and becomes hard to handle. Do not soften in the water bath! Hot water will leach out some of the ingredients and will change the physical properties.
2. To prevent long strings after adding compound, pull the stick away a little, getting a short string. Wait a moment for this thin string to cool. Then quickly pull away and the compound string will break.
3 . When building LIP a border, over-build, allowing the patient's musculature andlor your manipulations to push away the excess. Attempt to apply the compound evenly. If the addition is uneven, mold the compound to an ideal form with your fingers. Lightly lubricate your (gloved) fingers with Vaseline to avoid having the material adhere. 4.
After heating the border area with an alcohol torch, temper for a few seconds in 140" water. An exact temperature is not critical but the water should be hot. Tempering distributes the heat in the compound and the wet surface lessens the possibility of discomfort.
USE OF HEAVY-BODIED PUlTY FOR BORDER MOLDING:
The use of vinyl polysiloxane putty evolved in recent years so border molding could be done with less time and effort. The proceduresfor using putty are quite different than for compound. ADVANTAGES : 1. Armamentarium is simpler as a pin point flame and water bath are not needed. 2. No fear of patient discomfort from the heated compound. 3. More working time than compoound (about 5 min depending on brand). 4. Possible to border mold much larger sections. Deficiencies can be corrected witha small mix of putty. DISADVANTAGES: I . The putty will not adhere to the tray without an adhesive. 2. 'The putty can not be extended as far as compound and an accurate preliminary impression is necessary, i.e., one that captures all the supporting areas and extended into the vestibules. HANDLING PROCEDURES: 1. The custom tray must be about 2mm short of the attached movable tissues, held
under moderate tension. If any area is short (4-5 mm) it must be corrected with
compound. If there are too many short areas, check with your instructor as a
new preliminary preliminary impression and new tray may be needed.
2. Locate the "ah" line and mark it with an indelible stick, then Insert the tray firmly and the "ah" mark will transfer to the tray. The tray is reduced so it is Imm distal to the line. Immrtant: A distal border that is short must be corrected with compound or tray resin.
3. The tray is dried and the borders painted with putty adhesive. Add additional adhesive half way down the sides of the buccal and lingual for better bonding. 4.
Mixing: The putty comes in two colors and will be dispensed in measured amounts or in bulk containers. For the latter, use a tongue blade to remove the approximate amount needed (the measuring spoons are too wasteful). Use a different tonaue blade for each color as the same one would contaminate the entire amount.
5. Use vinyl gloves to mix. Complete the mix in 45 seconds. Roll out putty and make 2 -3 "worm-like" forms of about 3mm in diameter and 40mm in length. Plan on completing the border molding in 3 sections. Later these can be reduced to two or even one.
6.
Immediately start border molding with firm manipulations, as putty does not flow as easily as compound. Continue to manipulate the lips and cheeks, and tongue movements for lower, for about 3 minutes.
7.
Remove in 5 minutes. Borders that are too thick are reduced with a s h a r ~knife. Short areas are corrected with a small mix of putty (adhesive not required). Evaluate for seal and extensions.
8.
Final impression can be completed with rubber base (adhesive needed) or lightbodied vinyl siloxane (adhesive on internal tray areas only).
Note: The following instructions are for green stick compound but the principles apply to all border molding procedures. 1. Insert the lower tray and make certain the borders are about 1-2mm from the movable mucosa. Mark the distal end of the pear-shaped pads with an indelible stick and make certain the tray covers this line. 2. Usually it is difficult to check the lingual extensions. If the lingual borders seem over-extended, use Sorenson's paste and add a 2mm layer of paste with a cement spatula onto the borders. The borders must be dry or the paste will not adhere. Insert the tray and have the patient move the tongue into each cheek and lick the upper lip. If an area is over-extended, the paste will be wiped off, exposing the tray. Reduce 'these areas with a Melite bur and repeat until the paste is not longer displaced by the tongue movements. Other areas may be checked with the same procedure. 3. Make certain the patient has a CLIP of water and saliva ejector handy and rinses often as the mucosa must be wet to prevent burning or discomfort. It is wise to caution the patient that this material will feel warm and even hot at times but will not burn. A thin layer of Vaseline on the lips will lessen the chance of discomfort but don't apply too much as the lips will be too slippery. 4. The correct border form requires experience. 'The surface of the compound should be dull. If glazed or shiny it does not have good tissue contact. Add more compound and repeat. 5. If some of the compound flows toward the inside of the tray, remove it with a sharp knife. This done to prevent potential pressure areas and is usually done when the border molding is completed, and before the final impression. 6. Using a sham knife, reduce any borders that seem too wide or any other area that is sharp, seems over-extended, etc. As before, this requires an experienced eye and probably should be done by your instructor. 7, After each use of the compound stick, place it on a ceramic tile or glass slab. Otherwise, the softened end will adhere to the paper on your work space.
BORDER MOLDING:
These six areas would be doing this procedure with care and is recommended. When skill is acquired in the use of stick compound, the number of areas can be reduced. (1) Posterior buccal area: Add an adequate amount of compound. Instruct the patient to open wide, suck in the cheeks, or the cheeks can be manipulated. Grasp the cheek with thurr~band index 'finger and pull the cheek up; 'then mold the area with a massaging movement. Spend extra time on this area as it is important for good support and retention. Make certain the buccal shelf is covered; especially important when the ridge is flat. (2): Same as (1) on 'the opposite side. (5) Labial Area: Add a layer of compound from buccal frenum to opposite frenum. Temper and seat the tray. Instruct the patient to raise the lip a few times or gentl y raise it yourself and massage. Repeat if necessary.
(4 Lingual Anterior Areas: This area is very critical for a good border seal and retention. Add compound, insert and hold the tray in position firmly with your index fingers. Instruct the patient to protrude the tongue so it pushes on the base of the 'tray handle. This activates the floor of the mouth. Do not allow the patient to protrude the tongue beyond the lips as it may result in a short border and poor seal. Then ask the patient to lick the upper lip from side to side. It is usually necessary to repeat this procedure once or twice to obtain the best length and width. (5 and 6) Dissto-Lingual Area: Same as (4) but is a difficult area and requires practice and experience. Add the compound as evenly as possible and do not overheat. If the material is too soft, this border will be very difficult to manage. Seat carefully. Often it is necessary to retract the tongue with your mouth mirror in order to seat without bending. Use the same procedure as (4), but also instruct the patient to extend the tongue into the opposite cheek. Do not allow the tongue to extend any further or your border will be short.
BORDER MOLDING OF FRENULAE: 1.
Labial frenum: Heat with a pin-point flame in this area only, insert and pull the lip up and down a few times.
2. Buccal frenums: Heat in area, pull the cheek up, forward and back. Same for opposite side.
3.
Lingual frenum: Must be done accurately to preserve the seal. First examine visually and manually to determine the height and width. Then heat that area only using a pin point flame, insert and instruct the patient to protrude the tongue (not forcefully), and move it from side to side If a loss of seal is noted, add some compound and repeat the procedure.
CHECK FOR RETENTION AND STABILITY: Insert the border molded tray and make certain the tongue is in an anterior relaxed position. Instruct the patient to make some moderate lip, cheek and tongue movements. If the ridge is ideal or fairly good, the tray should not displace. Now is a good time to explain to the patient that only moderate movements are necessary for most oral functions and it is very important to learn not to do unnecessary and extreme movements. The patient should be told that it is usually impossible to obtain "suction" (retention) if the ridge is poor, very flat or high-thin. If the border molded tray does not have an adequate seal, i.e., depending on the quality of the ridge, obtain help from an instructor before proceeding. FINAL MANDIBULAR IMPRESSION:
NOTE: The final impression is completed with liqht-bodied polysulfide rubber base material. Medium-bodied material may be advantageous when the ridge is very flat but obtain advice before using. Heavy-bodied material is never used for a final impression. 1.
Remove the corr~poundfrom the internal surface of the tray. Using a sharp knife and also reduce any sharp projections. Do not reduce the height of the compound. If there is flabby tissue on the crest of the ridge or if the ridge crest is thin, use a Melite b ~and ~ rwiden and deepen the entire crest area about 1-2 rnni.
2.
Adjust the patient's head so the ridge is parallel with the floor when the mouth is open. Lubricate the patient's lips very lightly with Vaseline.
3. Squeeze out about five inches of impression material from each tube and spatulate until no streaks are present. Add about an even 3mm layer onto the tray and the borders. 4.
If the amount and viscosity of the saliva is normal, it is not necessary to dry the ridge. Rubber base has enough viscosity to displace the saliva. If the salivation is profuse, pack the lower ridge areas with 2 X 2's and remove just before inserting the tray.
41
5. Seat the tray in a similar manner as described under alginate impressions. Seat to place firmly, then hold in place lightly with the index fingers in the bicuspid areas with the thumbs under the mandible.
6. When the material starts to thicken, instruct the patient to lightly pucker the lips (or you can mold the lips and cheeks with your thumbs), lick the lower lip, push the tongue against the tray handle, and then relax. This repeated at least two more times. The complete set takes about 8-10 minutes, from the beginning of the rnix.
7. Retract the lips and cheeks to break the seal, and remove carefully. 8. Examine the irr~pressioncarefully for complete tissue contact, even distribution of material, and lack of pressure areas. Small border deficiencies can be corrected with soft wax. Small air bubbles can be left alone and corrected in the master cast. Small pressure areas can be scraped lightly or corrected later in the finished denture. However, large defects and pressure areas require another impression. Relieve the pressure areas with a large acrylic bur if in the acrylic tray and use a sharp knife if in compound. Remove all the impression material and repeat the procedure.
9. Remove any impression material from the lips with orange solvent. The patient will usually wish to rinse. Insert and check for extension, support, retention, and stability. (It is not always possible to check the final impression in the mouth due to large undercuts, tender mucosa, etc.) a. Extension - the correct extensions (borders) creates the border seal. Instruct the patient to open wide, and make moderate tongue movements. If the impression is overextended (or underextended due to lack of border sea.]),the denture will move in a superior direction. There should be little or no movement if the mucosa is normal and reasonably firm. b. S u ~ ~ o- apply rt pressure in the molar area on one side and the other. The impression should not move appreciably (unless you have excessive soft tissue).
c. Retention - apply pressure in the molar area on one side and then the other and toward the anterior. Little or no movement indicates the degree of border seal in the posterior buccal and lingual flanges. Apply pressure on the handle directed upward; this indicates the degree of border seal existing in the labial flange area. 'The impression should not move appreciably, ur~lessthere is excessive soft tissue. d. Stability - grasp the impression in the bicuspid area and attempt to displace it laterally. Little or no movement indicates stability. All final impressions are washed in tap water to remove saliva and debris. Plan to pour the impressions as soon as possible. Store temporarily in a wet paper towel.
MAXILLARY IMPRESSION
-
BORDER MOLDING:
1.
Insert the tray and check for over-extensions or interferences. 'The edges of the tray should be about 2 mm. from the vestibules, with the movable tissues under moderate tension.
2.
Mark the posterior border as before with the indelible stick. Insert the tray and make certain the posterior border is long enough to cover this line. If the tray is too long, the mark will transfer and you can trim the length accordingly. The tray should pass through the hamular notches and 1 mm past the vibrating line. For a Class Ill palate form, trim the tray exactly to this line. If the tray is 2-3 mm. short, it can be corrected with compound. If 4-5 mm. or more; consult with your instructor.
BORDER MOLDING:
Buccal Posterior Area (1):Build up this border generously as the proper height and width are very critical for good retention. To trim you may wish to have the patient: 1. Open wide and close. 2. Suck in cheeks. 3 . Move the mandible to the opposite side. If manual manipulation preferred, have the patient open wide and move the mandible from side to side to clear for the coronary process. Then pull the cheek down, forward and back; repeat twice. Buccal Posterior Area (2):Same as (1). Buccal Area (3): Build up this border a little thinner than (I),and instruct the
patient to suck in the cheeks. For manual manipulation, pull the cheek down,
forward and back a few times.
Buccal Area (4): Same as (3).
Note: When more skill is achieved, you can reduce the number of insertions by
corr~bir~ing
areas (1) and (3), and (2) and (4). Labial Area (5): Add compound and trim by instructing the patient to move the upper lip down, or the lip can be moved manually.
Posterior Area (6): Seal the posterior border with an even layer of compound about 2 mm high and 3 mm. wide. Note: The impression material is placed on the tissue side of the tray and not on the posterior border. Seat firmly. Instruct the patient to open widely to trim the ptergyomandibular raphae and then close. No movements are needed as a posterior seal will be carved later in the master cast. FRENULAE: Using a pinpoint flame, heat only the labial frenum area, insert and manually move the lip up and down a few times. For each buccal frenum, move the cheek down, forward and back a few times. Do each buccal frenum separately. Now check your border molded tray for retention and stability. Do not depend on the final impression for retention; you must have it now. See if the patient can dislodge the impression tray with moderate movements. Exaggerated movements or a wide yawn will dislodge most impressions, as well as the finished dentures, and is not a fair test. If the retention is inadequate, recheck your borders and try to determine where the border seal is leaking. The most common error is a short posterior border andlor an inadequate posterior seal, or a leak in the tuberosity area. A quick way to check these areas is to use some soft green wax (Bosworth's), where indicated, and replace with compound if border seal is achieved. Obtain help from an instructor if you cannot obtain a retentive border molded tray. PREPARATION OF TRAY FOR FINAL IMPRESSION: 1.
Remove any compound from inside the tray with a sharp knife but do not disturb the height of the borders and the post-dam area. Remove any sharp projections.
2. Drill a series of 2 holes (to relieve hydraulic pressure) with a 3/32 twist drill or No. 8 round bur in a straight handpiece. One hole is placed in the center of the palate and the other distal to the anterior papilla. 3.
Apply rubber base adhesive to the inside and peripheries. Wait about 10 min. for the adhesive to dry.
FINAL MAXlLLARY IMPRESSION :
Light-bodied polysulfide rubber base impression material is usually used. There are other impression materials that are advantageous for various situations and can be used when advised and supervised. Note: Remember that polysulfide irr~pressionmaterial is irr~possible to get out of fabric. D r a ~ the e patient properly. 1.
Adjust the patient's head so the maxillary ridge is parallel to the floor.
2. Lubricate the patient's lips with a thin layer of Vaseline. Don't use too much as the lips may be too slippery to control. 3.
Usually the saliva is not a problem as 'the rubber base has sufficient viscosity to displace normal saliva. If the saliva is thick and ropy, use a few drops of spirits of ammonia in a glass of water. Instruct the patient to rinse for a full rr~inutewith this mouthwash and then rinse with plain water.
4.
Use about five inches of rubber base from each tube for the average impression. Experience will dictate the correct amount of material. Do not be wastefu I.
5.
Spatulate the mix until smooth with no streaks.
6. Add a 3mm. layer of material to the tray and borders: evenly as possible.
7. Seat the tray in a similar manner as described under alginate impressions. Seat to place with firm even pressure, then hold in place lightly. Use your finger or a mouth mirror to quickly wipe away any material that flows over 'the soft palate but don't allow any material to flow down the soft palate and set up a gag reflex.
8.
The tray is held lightly in the open mouth position. When the impression material starts to polymerize, usually one or two minutes after insertion, manipulate the lips and cheeks as when border molding or instruct the patient to lightly pucker the lips, grin, move the jaw from side to side, and relax. 'The movements used for the functional method or manipulation method are usually repeated twice.
9. 'The complete set takes about 8-10 minutes from the beginning of the mix, depending on handling and humidity. In case of gaggers, add 3-5 drops of water to the mix. This will accelerate the setting time. 10. Removal of the tray is often difficult due to the initial adhesive qualities of the impression material and undercuts. Break the seal by reflecting the lips and cheeks. If this is insufficient, use your air syringe around the labial peripheries and especially around the labial frenum. 11. Examine the impression carefully for complete tissue contact, even distribution of material, and lack of pressure areas. NOTE: If possible, the border thickness of the final impression should be similar to the thickness of the 'finished denture. The final impression material over the border molded area should be very thin and may show through in some areas. If too rr~uch compound is evident, it is usually due to insufficient impression material or the border molded tray is over-extended. Consult with your instructor. Small border deficiencies can be corrected with soft wax (Bosworth). Don't correct small air bubbles with wax. These can be flicked off the master cast later. Small pressure areas can be scraped lightly or corrected later in the finished denture. However, large defects and pressure areas may require another impression. If another impression is indicated, relieve the pressure areas with a large acrylic bur if in the acrylic tray or use a sharp knife if in the compound. 12. Remove any bits of rubber base from the patient's lips with orange solvent. The patient will wish to rinse.
13. Remove any rubber base that extends past the posterior border with a curved crown and bridge scissors.
47
14. Insert and check the impression for extension, support, retention, and stability. Note: Some impressions cannot be returned to the mouth because of undercuts, patient discomfort, gagging, etc. a. Extensions - check the borders of the labial and buccal flanges by holding the lip and cheek slightly outwards while seating the impression. The borders of the irr~pressionshould lightly engage the tissues in the vestibules to create a border seal. b. Support - apply pressure in a tissue-ward direction alternately on one posterior-occlusal section and then the other. The impression should not move appreciably (unless the mouth has excess soft tissue). c. Retention - use the following tests: 1. Push up on the handle; this tests the posterior seal (remember that it will be improved later with an additional seal) and posterior border. 2 . Pressure on the right canine area, then molar area indicates the degree of seal on the left side. Do the opposite side the same way. The impression must not rock. 3. Push down on the tray handle. Resistance to displacement will indicate the degree of border seal in the labial flange area. d. Stability grasp the tray in the bicuspid area and attempt to displace it laterally. Little or no movement indicates stability. Note: It should be kept in mind that all of the above tests should be done with the realization of the quality of the ridge. A poor ridge should be tested lightly and a better ridge more aggressively.
-
15. The impression is washed with tap water to remove saliva and debris. 'The maxillary impression often has a layer of mucin that should be removed by rinsing with tap water and a pinch of plaster. Plan to pour the impression as soon as possible.
Maxillary and Mandibular Alginate Preliminary Impressions
Border Molded with Compound or Putty
Final Impression with Polysulfide rubber base
BOXING AND POURING THE FINAL IMPRESSIONS:
Objective: To obtain dense bubble-'free master casts from the final impressions. Boxing preserves the important height and width of the borders. Materials Needed: 1. Boxing wax -- 2 sheets 2. 112 plaster - 1I2 pumice mix 3. Heavy rubber band (2) 4. Wax paper 1.
5. Plaster bowl and spat~~la 6. Vaseline 7. Plaster knife 8. Wet-dry sandpaper
First remove the anterior extension of the tray handles with a carbide bur or a carborundum disc. The ridges should be parallel to the table top.
2. Make a mix of water and 112 plaster - 112 pumice. Place 2 mixes on a piece of wax paper so they are about 15 mm. thick and larger than the impressions.
3. Gently push the irr~pressions(tray side down) into the plaster-pumice mixes so the sides are about 2-3 mm. from the height of the borders. Work the edges with a spatula so the levels are even and smooth. Try not to flow any of the mix into the impressions, but if this occurs it can be removed (even when hard). 4.
When the mixtures are set hard, usually about 14 min., trim the sides with a model trimmer to 3 mm. width but 6 mm. on the posterior borders.
5. Lubricate the plaster-pumice with a thin coat of Vaseline; be sure to include the entire lingual area and all the land areas. 6.
Warm a sheet of boxing wax, wrap it tightly around the plaster-pumice matrices and hold in place with 2-3 heavy rubber bands. Score an inside line with a knife 13 mm. above the highest point on the impressions on two opposite sides.
7. A heavy mix of yellow stone is vibrated into the boxed impressions. Always add the stone to one end and allow it to flow to the other side. Bring the stone to the level of the marks on the inner aspect of the boxing wax. Wait until the
49
initial set has taken place and the stone begins to become warm. Cover with a wet paper towel. Allow the stone to remain undisturbed for a minimum of 30 minutes. Never allow a cast to remain immersed in tap water as stone is soluble in tap water. SEPARATING THE CASTS FROM IMPRESSION AND TRIMMING: 1.
Remove all the boxing and beading wax. The plaster-pumice is carefully removed with a plaster knife by cutting grooves, about 4-5 mm. deep, that approximate the tooth rows. The knife is used as a wedge to split off the plaster-pumice, usually in 3 pieces.
2. Soak the impressions and casts in hot tap water 1250 to 130" for five minutes. Although elastic impressions require no soaking to separate, it is advisable to warm the compound asundercuts are usually present. 3.
Carefully remove the impressions from the casts. Be especially careful if the ridges are thin. Clinging particles of impression material are removed with a stiff brush. Use any appropriate instrument or bur to remove any stone bubbles.
4.
Flatten the bases and true up ,the sides so the land areas are 3mm. wide except the posterior borders where thet are 6 mm. wide. Reduce the height of the land area if it exceeds 2 mm. above the border with a plaster knife or a Melite bur. 'The base should be about 13 mm. thick in the thinnest part. Smooth the side walls and base with black wet-dry sandpaper under running tap water.
BASE OF CAST
CROSS SECTION VIEW
(1 3 mm deep)
(2 mm deep) {
I
I I
RIDGE
I I
I
VESTIBULE LANDAREA (3 mm wide)
KEYING THE MASTER CASTS: Objective: To groove the niaster casts so that they can be returned to the articulator in the same position after processing or any time. With a sharp plaster knife or a Fast-Cut wheel, make four "V-shaped" cuts as shown in the sketch. The cuts are about 3 mm. deep and 5 mm. wide. Before mounting the casts, soak them in tap water for a few minutes and lubricate the grooves with Vaseline. 'This will facilitate separating the casts from the mountings and will also preserve the grooves so remounts are more accurate. NOTE: 'This is a keying method and not the splint-cast technique as used in occlusion. The long grooves are needed in case the laboratory technician must trim the casts for flasking.
Materials Used: 1. Auto-polymerizing resin 2. Surveyor 3. Alcote or Vaseline 4. Arbor bands
5. 6. 7.
4 paper cups
Sharp knife Polishing materials
Obiective: To fabricate close fitting auto-polymerizing acrylic resin baseplates and wax occlusion rims that will be used later for obtaining the occlusal plane, vertical dimension, centric relation, and the face-bow transfer. When this is accomplished the task of recording jaw relations, the transfer of the models to the articulator, and the try-in of the trial denture are easier with marked improvement of the occlusion and vertical dimension of the final denture. The surveyor is helpful for blocking out undercuts. A path of insertion is determined and undercuts blocked out using p lnJ baselllate wax. Do not use other waxes. Undercuts on the labial aspect of the maxillary cast may be reduced by having antero-posterior path of insertion. Excessive blockouts will result in a labial flange that will distort the lip uporb insertion. Either try to minimize the amount of blockout by using the surveyor and mark the path of insertion, or use an "open" labial flange. Note: For thin-spiny ridges, block-outs are necessary. Also add a 1 mm.. layer of wax along the sides to prevent breakage when removing the tray from the cast. The spiny area of the cast is often broken when this is not done and a new impression is often necessary. Make certain there is enough clearance for the undercuts and around thin areas so breakage does not occur.
-
2. Coat the cast and land area with Alcote or Vaseline. 3.
Auto-polymerizing resin is used with two small squeeze bottles of polymer and monomer. The cast is first wet with nionomer and then the polymer is sprinkled on, forming a thin layer of resin. The surface of the resin should look shiny and wet. This procedure is repeated until the layer of resin is about 3mm thick.
4.
The soft resin tends to flow so it is necessary to rotate the cast andlor use a large camel's hair brush to control the thickness of the resin layer. Try to obtain an even thickness of about 3mm.
5. Place the cast in a pressure pot, in warm water, in about 25 psi, for 10 minutes. 6.
Se~arateverv carefully. Inadequate blocking with wax or Alcote failure often leads to breakage of the casts. If a surveyor was used to determine a path of insertion, follow the lines on the cast and remove the baseplate with the same path. There will be less possibility of breakage and tlie block-out can be minimized. Make certain the anterior land area is not higher than 2 mm. or that will either break or will interfere with removal.
7. Trim the excess with an arbor band on a lathe and resin burs in a straight handpiece. Reduce the thickness of the resin over the ridge and to the labial and buccal aspect of the ridge. This will allow room for positioning the artificial teeth at a later time. This is especially irr~portanlif the ridge is large a.nd the inter-arch distance is limited. Smooth the baseplate with wet pumice with a rag wheel on a lathe.
FABRICATION OF THE WAX OCCLUSION RIMS
MAXILLARY OCCLUSION RIM: Objective: To construct a wax rim to be a substitute for the teeth. The occlusion rims are used for the occlusal plane, vertical dimension, centric relation, facebow, and the placement of the teeth. The mid-line, high smile line, and canine to canine distance are recorded on the wax occlusion rims. Materials Needed: 1. Pink baseplate wax 2. Hot plate 3. Spatula 1.
4. Knife 5. Alcohol torch 6. Stone casts of previous dentures
Apply a thin layer of sticky wax to the baseplate on the crest of the ridge.
2. Use only clean pink baseplate wax. Don't use the harder set-up wax. Warm by flaming 1 112 sheets of baseplate wax carefully. Roll tishtlv lengthwise, flatten on table, fold 1 inch of each end over (to shorten length) and adapt to the baseplate as follows. 4.
Flame the underside of the wax rim and position it on the baseplate. Seal it to place with a hot spatula.
5. Warm a sheet of baseplate wax over a Bunsen flame and fold it into a rectangle; 4 to 5 rnm. thick and long enough to extend around the wax. Adapt the softened wax on the labial and buccal areas to properly build out the contour. Mold the canine areas to give a slight eminence. Smooth and finish shaping the contours with the occlusal plane former. The posterior width is about 6 mm. and the anterior portion 3-4 mm. Note: Most occlusion rims are far too wide and crowds the tongue space. Study the stone casts of the previous dentures (especially if they were satisfactory) and simulate the arch form and occlusal widths.
6.
The anterior length of the rim should be about 22 mm. from the highest area of the labial flange to the occlusal edge.
54
7. Construct the maxillary occlusion rim so it will be over the probable position of the teeth. The anterior portion is alwavs labial to the crest of the ridge. In addition, the anterior portion must have a slight labial inclination of about 50. The posterior areas have a 50 linaual inclination. All the lingual walls are 900 to the occlusal plane. 'The distal end of the rim runs at an angle toward the posterior border, starting at about the distal of the 2nd molars. Studv the illustrations:
ANTERIOR PORTION
34MM.WIDE POSTERIOR PORTION 6 MM. WIDE
LINGUAL INCLINATION
50 BUCCAL HEIGHT 22 mm.
LABIAL HEIGHT 22 mm.
MANDIBULAR OCCLUSION RIM: The procedures for making the mandibular rim are very similar to the maxillary rim except that less time is spent contouring since the lower rim will be contoured to match the upper rim as a patient procedure. Make the height of the rim about 20 mm. from the labial border to the incisal edge, all at straight angles except the posterior edge which angles down, and in front of the pear-shaped pad. Studv the illustration:
... ......
,
.:........ . ..:.
-
RIM HEIGHT 20 m.
1
NO LABIAL INCLINATION
Note: The rims must be neatlvconstructed as patients begin to base their feelings about their new dentures on the appearance and feel of the occlusion rlms .
THIRD VISIT
OCCLUSAL PLANE, VERTICAL DIMENSION,
CENTRIC RELATION, INTEROCCLUSAL DISTANCE,
FACE-BOW TRANSFER
MID-LINE, SMILE LINE, CANINE TO CANINE DISTANCE
AND SELECTION OF THE TEETH
Materials Needed: Mouth mirror Hand rr~ irror Indelible stick Soft lead pencil Alcohol torch Pink baseplate wax Green stick compound Fox occlusal plane Sharp knife
Flexible ruler Compound heater at 140" Face bow assembly Hot plate Wax spatula Cold water Shade guide Mold guide Denture adhesive
Note: The- denture manual must be open for reference in the clinic. -
OBJECTIVES: 1. 2.
3.
4.
Occlusal plane: To determine the horizontal and vertical level of the teeth. Vertical dimension: To determine the amount of space between the rims with the jaws at rest and with the wax rims in occlusion. Face-bow transfer: To record the position of the jaws as related to the opening axis of the mandible and transfer this position so that the casts on the articulator will have the same relationship to the opening axis of the patient. Centric relation: To record the most posterior position of the mandible to the maxilla and transfer this position to the articulator.
OCCLUSAL PLANE:
The occlusal plane is an imaginary surface that is related anatomically to the cranium and theoretically touches the incisal edge of the incisors and tip of cusps of the posterior teeth. It is accomplished with the use of maxillary occlusal rim. The plane must be close to the middle fibers of the buccinator and correctly related to the tongue for proper speech and food bolus control. GUIDES:
1.
Parallel to Campers Line
2. Parallel to the pupils of the eye or if the eyes are not level, 90" to the loog axis of the head.
3. In length, the edge of maxillary rim is trimmed to about the length of the relaxed upper lip (average). Older patients tend to have pendulous lips and shorter teeth. Im~ortant:Always compare the length of the maxillary rim with the old denture. Very often, the patient prefers to have the teeth about the same length or a little longer.
1.
Draw a line 2 112 inches long on each side of the face (Camper's line) with a bamboo pen or an indelible stick. These marks are easily removed later with an alcohol sponge.
2. Place the maxillary occlusion rim in the mouth and make certain it is comfortable and fits reasonably well. NOTE: A light layer of denture adhesive powder or paste is usually necessary for retention during this appointment and subsequent procedures. If used, denture adhesive must be used carefully as heavy layers in the baseplate can change the vertical dimension and can even cause a shift to a forward or lateral position.
'The horizontal occlusal plane is parallel to the pupils of the eyes
The saggital occlusal plane is parallel to the ala-tragus plane (Camper's Line).
The correct method is to licrhtlv dust the baseplate with an even layer of adhesive powder on the tissue side, or if using paste, use it sparingly. Wet the baseplate before insertion. Alwavs have water available in a water bath or a rubber bowl so the wax rims or dentures can be wet before insertions. A large dry object is not very comfortable and many of our elderly patients have very dry mouths. 3.
Reduce or build out the labial portion so the lip is properly supported and looks "natural." The patient's old dentures, if satisfactory, may be used as a guide for developing the occlusal plane.
4.
Establish the correct length: Check the previous denture and decide whether to duplicate the tooth length and position or make a change. Trim the wax accordingly. Have the patient count 'from 50 to 60 rapidly and note where the rim is in relation to wet-dry line of the lower lip. The lower lip should contact the maxillary rim near the wet-dry line when saying "F" or "V' sounds. Don't be concerned if the speech is poor as a wax rim is not conducive to good enunciation. (Also, do not bother checking the "S" sounds as occlusion rims do not have any overlap.) If the rim is too long, reduce it until it is correct. At the same time parallel the rim with the pupils of the eyes and Camper's line. Use the Fox Occlusal Plane to check for parallelism with the marked planes. Use the hot plate to reduce and shape the wax. Remember that this plane is temporary and may be changed for esthetics, function, etc.
5.
Mark the maxillary rim to aid in the selection of the teeth. a. Mark the midline. Determine the midline using the philtrum of the lip, labial frenum, and the midline of the face. The nose is seldom a reliable guide. b. Have the patient relax the lips. Mark the wax rim at the corner of the lips with a #7 wax spatula (don't use any sharp instrument). These marks are the approximate width of the six anterior teeth. c. Have the patient smile broadly and mark the high lip line with a wax spatula. 'This may be a useful guide for the length of the upper anterior teeth.
VERTICAL DIMENSION OF OCCLUSION:
Vertical dimension is a height of the face between any two arbitrarily selected points that are usually located on the tip of the nose and on the chin. Rest Vertical Dimension is the vertical dimension of the face with the mandible in a rest relation (V.D.R.). Occlusal Vertical Dimension is the vertical dimension of the face when the teeth or occlusion rims are in contact in centric occlusion (V.D.O.). All persons with natural dentition or with dentures must have a rest vertical dimension. At rest position, the teetli of the upper and lower arch are separated. A correct rest position is needed for muscle relaxation, patient comfort, and speech. During speech, the teeth never contact. It is necessary that the mandibular rim be reduced enough to give the patient an interocclusal space (freeway space) that averages 2 to 4 mm. with the mandible at rest, however it can vary from 1-10 rnm. NOTE: The maxillary rim has been contoured for esthetics and phonetics so only the mandibular rim is altered.
IMPORTANT: Keep in mind that face height (V.D.) will gradually reduce with natural teeth due to wear and other factors. Edentulous patients exhibit the same phenomenon so it is natural to see a small but constant reduction. If the patient has dentures and the vertical dimension seems satisfactorv (as determined by clinical judgment, esthetics, and phonetics), it is often best to reproduce this same jaw relation. Do not try to evaluate 'this yourself, but seek3he advise of your instructor. In any case, it is necessary to aquire experience in these traditional methods: .-
1.
Use a carbide resin bur and thin (or shorten if necessary) the base plates in the pad and tuberosity area. The jaw relations are of prime importance and interference or contact of the bases must not occur. These areas are often thinned to prevent pinching or cheek biting.
2. Place a small dot on the tip of the nose and the chin. Do not place the lower dot on or near the lips.
3.
Determine the vertical dimension of rest. 'There are many methods to determine the V.D.R. but the following ones are most useful: a. Seat the patient in an upright position with no headrest support. lnstruct the patient to uncross the legs and let the arms rest limply on the arm rests, and relax. Have patient lick lips and close slowly until the lips barely touch. Measure the distance between the dots two or three times. If the measurements are consistent, it is probably correct. Large discrepancies, 2-5 mm., suggest an instability from nervousness, fatigue, poor coordination, etc. Note: Use a Bolev clauae for all measurements and not a tongue blade. b. lnstruct .the patient to say the letter "M" and hum, and measure while humming. The "M" sound is often the same or close to V.D.R.. c. lnstruct the patient to open wide for one full minute (fatigue method) and then close to a position that feels comfortable. Measure again.
If two or more measurements are about the same, the correct vertical dimension of rest has probably been recorded. It is necessary to reduce the vertical dimension of rest to obtain the vertical dimension of occlusion. If the measurement of the rims in contact is the same or greater than the V.D.R., the V.D.O. is excessive. &evaluate. 4.
Now, clinical judgment must be used to determine the interocclusal distance. The average is 2 to 4 mm. Older patients require the top range. Young patients the lower range. Retrognathic (Class II) require more (4-6 mm. and sometimes more) and prognathic (Class Ill) require the least (1-2 mm.). Poor ridges may benefit from 1-2 mm. more, favoring the poorer ridge.
5. Determine the vertical dimension of occlusion by subtracting from the rest vertical dimension the amount of interocclusal space desired. If the distance between dots at rest is, for example 64 rnm, and it is decided that 3 rnm. is the correct interocclusal distance, close the Boley gauge by 3 mm. to 61 mm. 6.
Reduce the mandibular wax rim using the hot plate so it's in occlusion and corresponds to the occlusal vertical dimension.
61
7. Re-evaluate your results as the V. D.O. is very important. It can be changed while the dentures are in wax but it's less work if close as possible. Make certain you can explain how you arrived at this V.D.O. before your instructor evaluates your record. FACE-BOW PROCEDURES: 1.
Notch Maxillary Rim: Use a warmed knife to cut two "V-shaped notches, bucco-lingually in about the bicuspid and molar areas in the maxillary occlusion rim. The notches should be about 2 rnm. deep and at opposing angles to each other (as illustrated). Make certain the midline has been located and marked with a visible groove.
A
&)~mm.
cross section
2. Apply about a 3mm. layer of softened green stick corr~poundon the face-bow fork so the compound will contact the entire rim.
3. Apply a layer of Vaseline on the occlusion rim and place it on the softened green stick compound, making certain that the midline mark is lined up with the center line on the fork. 4.
Place the rim and attached fork in the patient's mouth and ask the patient to support the asserr~blywith hisher thumbs.
5. Assemble the face-bow as described in the Panadent manual.
FACE-BOW TRANSFER: Objective: To obtain a face-bow record from the patient and to transfer the axis to the articulator and orienting the maxillary cast in the same relationship to the opening axis of the mouth. THE USE OF THE PANADENT FACE-BOW: The Panadent face-bow is an arbitrary (not a hinge-axis) face-bow, using the ears to locate the bow in an arbitrary relationship to the opening axis of the patient. The third point of reference used for this face-bow is the nasion.
1. BITEFORK
2. HMWRENCH
3. NASION RELATOR 4. FACE-BOW FRAME
5. BITE FORK AlTACHMENT POST
1. Loosen the large lock screw at the
anterior end of face bow:
2. Have patient grasp side arms of bow
and position them close to ears while operator slips loosened doubled toggle over protruding stem of bite fork.
3. Instruct patient to hold ear plugs firmly
into auditory meatus while operator tightens large lock screw.
4. While patient continues to hold side
arms of bow, adjust bow vertically until nasion relator is contacting patients nasion. Push firmly back against nasion and lock with thumb screw.
5. While patient continues to hold side arms, grasp double clamp to offset torque and tighten securely to stem of bite fork with hex wrench.
6. Grasp single toggle clamp to offset and tighten securely to vertical post of bite fork asserrlbly wi'th hex wrench:
NOTE: All the face bow corrlponents are now in their correct positions and all toggle clamps and thumb screws have been tightened. The entire assembly is ready to be removed.
7. Loosen the top lock screw and retract the nasion relator. 8. Loosen large lock screw and have patient retract ear plugs:
9. Instruct patient to open mouth.
Remove bow forward away from patient's face.
10. Carefully remove the maxillary
wax rim, put the face-bow asserrtbly aside and proceed with the next procedure, the C.R. record.
CENTRIC RELATION:
Centric relation is the most posterior relation of the mandible to the maxilla at a selected vertical dimension. Unlike a patient with natural teeth, C.R. must be recorded for edentulous patients as it is the onlv position that is repeatable. The centric relation is obtained using wax occlusion rims at the recorded vertical dimension of occlusion. 1.
Prepare the mandibular rim marking the distal of the canine area and removing 2 rrim. of wax in the posterior area on each side.
2.
Make undercut grooves in the reduced areas (needed for retention of the recording material).
3. Vaseline the occlusal area of the maxillary rim and place in mouth. Soften a half stick of green stick modeling compound in a compound heater at 140°F. Don't leave the compound in the water too long as it will become sticky and hard to handle. Knead the compound so it is uniformly soft. Note: If a compound heater is not available, the compound stick can be flamed and dripped onto the wax rim. Flamed compound is very sticky so Vaseline the opposing rim liberally and make certain to add thin layer to the patient's lips.
67
2. Loosen hex head set screw on cross bar of face-bow to remove bite fork
assembly.
3.
Attach the Panadent jig to the articulator.
4.
Place the bite fork assernbly.
5.
The cast is then securely seated in the denture base with the occlusal rim
%Firmly resting on its biteplane imprint.
NOTE: Review the Panadent manual for more details. Note that the procedure is the same except for the use of the jig.
6.
The upper member of the articulator is swung back and plaster of suitable consistency is placed on the cast. The upper member is swung forward to attach the mounting plate and bring the incisal pin in contact with the incisal guide. The mounting is completed with plaster and excess material is removed to expose the top surface of the mounting plate. This permits convenient removal and accurate re-attachment to 'the inslrument.
7. After the plaster has set, remove the face-bow and occlusal rim, and also the incisal pin extension. Trimming is completed to expose a sharply defined line at the junction of the stone cast and plaster mounting.
'MOUNTING THE MANDIBULAR CAST: 1.
Remove the Panadent jig and attach a mounting ring.
2. Re-check to see that all the articulator controls are locked and the incisal pin is open to approximate the distance between the anterior rims.
3. Lute the maxillary baseplate and rim to the maxillary cast, the maxillary rim to the mandibular rim, and the centric relation record to the mandibular baseplate to the scored mandibular cast. The cast heels must be clear and
baseplates clean of debris. If the baseplates are touching, the procedure was incorrect and centric must be retaken. 4.
Invert the articulator.
5. Make certain there is a layer of Vaseline in the grooves. Place tape around the lubricated cast and articulator.
6. Mix plaster and attach to the mandibular element. The lower membrane of the articulator is swung back and an adequate amount of plaster is placed on the cast. The lower member is then swung over to attach the mounting plate into the mounting medium as well as to bring the incisal pin into contact with the incisal guide, making absolutely certain that the condylar elements of the instrument are locked against their stops in centric position.
7. After the plaster has set, carefully open the articulator. Remove the green stick compound (centric relation record).
8. Loosen the incisal pin locking screw and close the articulator to permit the anterior rims to touch. This will restore the original vertical dimension of occlusion established with the occlusal rims on the patient. Add pink baseplate wax to the posterior wax occlusion rim so the correct vertical dimension will be maintained, especially when arranging the anterior teeth. Allow the pin to touch the incisal guide and lock in place. It is rare that the incisal pin will be at zero (middle line). Record the reading on your work sheet for the correct vertical dimension. Make sure your articulator is always set at this reading when working on the dentures for this patient. 10. Separate, remove excess plaster and tape, baseplates, and finish. Remove
all excess plaster with a plaster knife. Remove all excess plaster from the articulator making certain all screw holes are clear. Finish smooth with wet-dry sandpaper under running tap water. 11. Replace the mountings on the articulator. Make certain the mounting plates and the articulator are free of any bits of plaster or debris. Replace the mountings on the articulator. Tighten the holding screws securely.
71
Note: With the occlusion rims removed, study the relationship of the casts. If the ridges have resorbed evenly, the crests are usually parallel to each other (Class I jaw relationship only). If there is more inter-arch space anteriorly, the vertical dimension may be open (excessive). If there is less anteriorly, the vertical dimension may be closed. Keep these possibilities in mind and re-check the vertical dimension at the next visit. A Class II jaw relationship will usuallv converge and a Class Ill will always diverge.
SELECTION OF THE ANTERIOR ARTIFICIAL TEETH: The selection of all teeth are made during this visit. Obtain an anterior and posterior Portrait mold guide and shade guide from the 2nd Floor Dispensary. There are many excellent artificial teeth, but in order to simplify ordering and teaching we use the Portrait teeth, made by Dentsply Company. Densuply states they come closer to the look and wear of natural teeth than any plastic teeth previously available. Porcelain teeth are occationally used are available in Bioform and Biobland (brand names) . 1.
An ideal guide for selecting teeth is pre-extraction casts but they are rarely available. Pre-extraction photos are often useful and you should always ask the patient to look for some that display their natural teeth. Don't lose them!
2. The best practical guide is the evaluation of the present dentures, especially if they were irnrnediates. Unfortunately, many dentures have been made with teeth that are too small and too white. The patient and his family and friends get used to them and it is often difficult to make any changes. A careful evaluation of the patient's desires must be made as some would welcome a change from the "denture look". Some will tolerate only a small change, and others will not be happy unless the new dentures look exactly like the old ones. Often a short informative talk using some of the tooth manufacturer's (or preferably your own) "before and after" photos can be very effective in motivating patients to accept a more natural tooth selection. Do not try to talk your patient into accepting your concepts of "correct" teeth, -especially if they prefer white, even teeth. Keep in mind that patient satisfaction is the most irr~portantconsideration. 3. Whatever approach is used, an appreciation for art and composition is necessary to achieve natural looking teeth. 'This can only come from study and experience.
SELECTION OF RESIN OR PORCELAllV ANTERIOR ARTIFICIAL TEETH: 1. Resin teeth will be used for most dentures and are especially indicated when:
a. Ridges are large andlor 'the inter-arch space is limited. b. The denture opposes natural teeth or a fixed or removable partial denture. c. The patient is aged or sick and debilitated. d. The patient wishes to have crowns or inlays over one or more anterior teeth. e. The patient has worn a denture with plastic teeth with no apparent problems.
Note: Portrait teeth are only made in resin.
2. Porcelain teeth (available in Bioblend and Bioform) are selected when: a. None of the above criteria apply. b. The patient has worn a denture with porcelain teeth with no apparent problems. There may be a reduction in chewing efficiency when resin teeth are selected. SHADE SELECTION: The shade is selected with the Portrait shade guide. There are 24 shades; enough to fulfill the color requirement of any denture patient. The large selection seems confusing but you will soon note that certain shades will be used the most. Shades A,B,C, & D (16) are the most useful and are called characterized shades as they are a subtle mix of many shades. The last 8 are the Bioform shades, B59-882, and are not characterized and do not look as natural. They are included as Bioform teeth and shades have been sold for many years and it's often necessary to match them. 1. For youthful patients, use lighter shades with a bluish incisal. 2. For older patients, use a darker shade with mostly body color. 3. If the patient has dark hair, brown eyes, and dark skin, darker shades with more yellow and brown will look more natural. 'This rule does not apply for Black patients as they often have very wl-~iteteeth. 4. If the patient has blue eyes and fair skin, use lighter shades with more gray. 5. Consider the ~atient'sdesires: Many patients have very definite ideas on tooth color and will often not accept the above guidelines. Don't let the patient get a hold of the shade guide; many will select the pearly white A1 !! Select a shade that you think is suitable and let them make the final choice.
7. Consider the patient's old denture. Do they like the color of the teeth? If they think the color of the old dentures teeth were satisfactory, match them closely. Keep in mind that teeth discolor and other manufacture's shades may be somewhat different. Note: Sterilize before returning the teeth to the shade guide. MOLD SELECTION:
The mold refers to the size, shape and facial profile of the tooth. 1.
Size: a. When selecting the tooth size, it would be best to have the patient's own teeth or pre-extraction casts, but these are seldom available. Ask the patient to bring you some old photographs that show the natural teeth. b. Evaluate the present denture. Have a discussion with the patient about the size of teeth in the denture. Was the patient pleased with the old denture? Using the old denture and a flexible ruler, measure the width around the labial curvature from distal of canine to distal of canine. If the patient was satisfied with the previous denture, use this measurement as a guide. Even if the patient would prefer to have smaller or larger teeth, the old dentures provide the best possible starting point. c. Another method is to measure the maxillary occlusion rim that has the high lip line, the labial contour lines and the midline. Using a flexible ruler, measure between the lines drawn on the labial curvature of the wax rim. This provides an a guide for the width of the maxillary six anterior teeth. These measurements can be found in the Bioblend mold guide chart that is usually placed in the mold guide or can be obtained separately from the dispensary. d. The width of the face is measured between the zygomatic arches. Victor Sears has shown that about Booh of all central incisors have a width derived
from dividing the inter-zygomatic distance by 16. 'This 1-16 ratio is easily obtained with the use of a plastic face frame, called the Trubyte Tooth Indicator and can be obtained from the Densuply Co. e. The length of the teeth may be determined by measuring the high lip line marked on the wax rim. Teeth are more esthetic than the pink denture base. If the distance from the incisal edge of the rim to the high lip line is 10 mm., look for a cer~lralincisor that is about 10 mm. in length. Remember these lines are only guides, but they're useful starting points.
2. Shape (mold) of the anterior teeth: a. Outline of the face: In many cases, the outline of the face and the outline of the central teeth are similar (square face, square teeth, etc.). 'The concept was suggested by Leon Williams, 1914, as a method of selecting 'the maxillary anterior teeth. Williams wrote that the facial outlines have three basic forms: square, tapering, and ovoid . These basic forms are combined into 4 more groups: tapering ovoid, square ovoid and square tapering and square tapering ovoid. b. Dentoaenic conceDt: 'This method of selecting (and arranging) anterior teeth was developed by Roland Fisher and John Frush. They believed that the most pleasing esthetics is achieved by artificial teeth that reflect the patient's age, sex and personality. The age effect is achieved by 'selecting and re-contouring teeth so younger patients have teeth with more translucent incisal edges with little or no wear. Older patients have all body color, achieved by tooth selection andlor grinding. The sex effect is obtained by selecting and re-countouring the teeth. Teeth for females will have rounder incisal edges and smaller lateral incisors and canines. Males will have teeth that are more square and have larger laterals and canines. 'The personality effect is subtle and requires a more "delicate" or "rugged" selection and arrangement. More information on this concept is presented in your lectures and students are encouraged to read the classic articles by
Fisher and Frush in the Journal of Prosthetic Dentistry, 5586, 1955; 6:160, 1956; 6:441, 1956;7:5, 1957,8:558, 1958; 9:914, 1959. Note: Both the typal and dentogenic methods have no scientific basis but provide pleasing cosmetics. 3. Profile: The profile of the patient may be flat, concave or convex. 'The teeth
should be selected accordingly. 4.
Tlie mold is selected by evaluating the outline of the face. If the patients face is square and tapering, look at the teeth in the mold guide under Square Tapering. The size will be determined by matching the patient's old denture or using the measurements from the wax rim. The width of the six maxillary anterior teeth car1 be obtained by using the mold guide teeth and measuring from the distal of each canine. This measurement can be obtained more easily from the Portrait chart. The dentogenic concept can also be applied as the mold can be modified to harmonize with the age, sex and personality. This concept must be studied and well understood before it can be utilized.
5. After selecting the teeth from a mold guide, they can be arranged in some soft wax and placed behind the upper lip. Study selection carefully and try the other molds. Show the selected mold to your instructor for approval or change. 6.
Usually it is best not to show the patient the selected teeth. 'They can't really evaluate the teeth as viewed in the wax as the lip is distorted. They may be unduly concerned as the mold guide teeth are opaque and dark, and may think these will be the ones that will be used. Explain that the best way to see the new teeth is at the next visit in a pink wax base. Some patients will insist on seeing the teeth and there should be no hesitation to grant this request.
7. The following will help when looking at teeth in the mold guide. The first number of the numbered tooth (21XI 31F, 55D, etc.) indicates: 1. (one) is a square tooth 6. ((six) is an ovoid tooth 2. (two) is a square tapering tooth 7. (seven) is a square tapering 3. (three) is a square ovoid tooth ovoid 4. (four) is a tapering tooth 5. (five) is a tapering ovoid _ toot11 .
The second number indicates: 1. Straight or flat teeth on labial surface (1, 2, 3);
Curved labial surfaces (4, 5, 6)
2. Numbers 1 and 4 are wide in proportion to the length
Numbers 2 and 5 are medium
Numbers 3 and 6 are short in proportion to their width
The letter indicates: mesial-distal widtth. NOTE: Remember that the mold number is on tissue side of the ridge lap of the tooth and to return teeth to their proper places in the mold guide after sterilizing and cleaning. This is very important as mold guides are becoming increasingly expensive to replace.
DENTURE ANTERIORS Powlain AnMrior
Plastic Anteria Mould Number
Pins
DENTURE POSTERIORS
ORDERING ANTERIOR AND POSTERIOR TEETH:
Below is the tooth order to be turned in at the Gold Window:
Ul~iversi~y of Soutl~el.~i California SCHOOL 01: DEN'I'ISTRY DEPARTMENT OF REMOVABLE PUOS~I'~OIJON'SICS TOOTH ORDER FORM DATE
..................................
TRUBYTE
--------- MATERlAL --ANTERIORS NAME MOULD SHADE ...........................................................................................................
%x%
MAXII-LARY
CENTRAL
@SIN LA'ERAL
--3
Lf
.T3
1
5
......................................
CUSPID MANOIUULAR
&at%
CENTRAL
TRUBLBNO
LATERAL
I
1 ,
.............................................
CUSPID
& zoo 30'
3 3 O
POSTERIORS PORCELAIN
I
-
-3 3 2 -
-
PATIENT
...............................................................................................................................................
STUDENT
....................................................................................................................................................
INSTRUCTOR
1.
MAXILLARY
................................................................................................................................................
Portrait teeth will be used in most cases. Occasionally porcelain teeth are indicated. Circle the selected material.
2.
Write in the selected mold for the centrals, laterals and canines. Also, write in the selected color.
3. 'The correct mold for the mandibular teeth is obtained by a formula that is on the chart. This formula is used for Class I jaw relationships. Class 2 patients will usually require narrower teeth and Class Ill wider teeth. 6.
.
All anterior teeth may be ordered individually (often needed for RPDs). Dentures require the entire set. Posterior teeth are sold only in complete sets of uppers and lowers.
SELECTION OF POSTERIOR TEtlH: Posterior teeth are selected by cusp height, resin or porcelain, mold and shade. 1.
Cusp height: 10 degree are called called low cusp, are easy to occlude, and are frequently used. 20 degree have a higher cusp and are more difficult to
articulate. 33 degree teeth were originally designed by A. Gysi and have
been used for many years, and are the preference of many prsthodontists.
a. For well coordinated paiients with good ridges, use 33 degree teeth. b. For older patients with poor ridges, especially ones with health problems
and poor neuromuscular control, use 0 degree (flat or monoplane) teeth.
c. For retrognathic ridge relation, use 0 or 10 degree teeth. d. For prognathic ridge relation, use cusp teeth. Cusp teeth can be used as
the patient has little or no protrusive component in the chewing cycle.
2.
A more important consideration is the teeth in the previous denture. For experienced and satisfied patients, di~plicatingthe previous teeth, i.e., size, cusp form, and material is usually a wise choice. - ,,
3.
For patients who are not satisfied with the masticatory function of conventional teeth, consider the use of lingual bladed teeth. Recommended reading: Levin, B.: A review of artificial tooth forms including report on a new posterior tooth. J. Prosth. Dent. 38:3-15.1973.
TOOTH MATERIAL: Plastic and porcelain:
Plastic teeth are softer, bond to resin, and are especially indicated for:
a. Lack in inter-arch space b. Single dentures opposing natural teeth or gold. c. Very poor ridges and mucosa d. Patient presently wearing and accustomed to acrylic resin. e. Aged a.nd debilitated patients Porcelain teeth:
a.. Harder than resin teeth and better wear
b. Better mastication, compared to resin teeth. c. Difficult to polish d. Require mechanical retention to base; pins or diatorics. e. Very abrasive if the glaze is not intact. Note: Most dentures will be made with Portrait plastic teeth. MOLD SELECTION FOR POSTERIOR TEETH: 1.
The selected size is the mesial-distal length of the combined posterior teeth. The mesial-distal length of the bicuspids and molars range from 30 mm to 36 rnm. For example, it this measurement 32 mm and you have selected 10 degree teeth, you need a number 332 mold. The width and heigth of the teeth will harmonize with this measurment. Try not to use a very large mold such as 336 as the teeth will be large and not amenable for efficient chewing. Also make certain the teeth will harmonize, in heigth, with the anteriors and not look like corn on a cob!
Note: Study the mold charts.
OPTIONAL VISIT
ARRANGEMENT OF THE ANTERIOR TEETH Objective: Some patients are very concerned about esthetics and especially the position of the front teeth. Most prosthodontists and some general practitioners arrange the anterior teeth as a separate visit. Discuss this with your instructor. POSITIONING THE CENTRAL INCISORS: 1.
Set the condylar guidances at 300 and the condylar posts at 150. Make certain to remove the soft pink wax from the labial and lingual surfaces before placing the teeth. Use the harder set-up wax (dark orange color) for setting the teeth. Don't forget to inquire whether if your patient prefers the same arrangement as the old denture or some changes.
2.
Position the two centrals using the midline, high lip line and the edge of the wax rim for guides. Insert and check for length and mid-line symmetry.
Adjust the length if needed and make certain the mid-line and mid-axis are correct. Fig. 1 shows a solid line on the correct mid-line. Fig. 2 shows the distorted appearance when the teeth have an incorrect long axis.
(i ) :
3. The determination of the length, labio-lingual
P
&-
position and inclination (pitch) is greatly aided with phonetic tests. The " F (and "V') sound is used to evaluate if the edges of the centrals
firmly contact the wet-dry line of the lower lip.
The patient is instructed to count from 50 to 59, ra~idlv.Slow counting will enable the patient to "place" the lower lip as needed whereas it is desirable to see the habitual relationship. It may be necessary to increase the tooth length if too much air is escaping or shorten if the air seems blocked. The labiolingual position of the teeth may require a change if the teeth contact the lip anterior or posterior to the wet-dry line. 4.
Observe the face, from the frontal view and profile, for proper lip support. The lip is mainly supported by the teeth. Unless
the ridge is flat, the labial flange should be thin.
Profile view: the upper lip is usually usually'concave.
The narrow vertical groove between the nose and
lip (philtrum) should not be obliterated.
A serious error is to place the teeth too lingual and then provide lip support with a ,thick l:lange. 'The inadequate support from the teeth and excessive support from the
/ 5.
flange will result in a distorted lip.
It is sometimes an advantage to position one central slightly ahead of the other and vary the axis slightly, creating a more natural effect.
POSITIONING THE LATERAL INCISORS: 1.
A mesio-labial rotation usually looks good in a female or delicate patient and is called a "soft" lateral (Figs.1 and 2). This makes the tooth look narrower and enlarges the embrasures. Vary the amount of rotation slightly on each side.
2. For a man and a more vigorous effect, try a mesio-lingual rotation, called a "hard" lateral. This makes the tooth look widerlfigs.3 and 4).
3% Place the lateral incisors higher than the centrals depending on age. This begins the "smile line".
Y. Young patient - 1 mm. M. Middle age - .5 mm. 0. Old age - .25mrn. or flat
D :INTER-
~NCISAL DISTaNCE.
THE "SMILE LINE: A smiling face will look better if the maxillary teeth are arranged to follow the curve of the lower lip (Figs.1 & 2). A flat plane or especially a reverse smile line (Fig.3) will not be compaable to good esthetics.
Fig.1: The smile line is generally more curved in females and younger people.
I
.f
\.'.
,/'
N
Fig.2: The smile line is generally less curved in males and older people.
I
2
POSIl'IONING THE CANINES:
The canines control the arch form and complete the smile line. The canines must be
rotated so the mesial half is in harmony with the anterior teeth and the distal half
with the posteriors. The canines have 3 basic positions:
First basic position:
The neck must be out and the incisal in.
Less for a patient with a square face and
more if the face is tapering.
L~
t
*
*
1
Second basic position:
Onlv the mesial surfaces must show.
Display of the distal surfaces may be
from inadequate rotations. -
B
3rd basic position: Must be vertical from the saggital view (right angle to occlusal plane). A small mesial tilt is permissable but never to the distal. EMBRASURES: The incisal edges of anterior teeth are rarely square. Rounded corners and rotations reduce the size of the contact areas and create embrasures. The use of square teeth, no rotations, and a flat occlusal plane will create an artificial and LI~-estheticlook.
The use of rounded incisal edges, rotations and re-shaping will create embrasures. The curve for a smile line will also enhance esthetics. DIASTEMAS (SPACES): A diastema (space) is often seen in natural teeth and is especially useful on the dominant (larger) side. 'The space can be between the central and lateral, or between the lateral and canine, or both. The space should be no narrower than I mm. as food may wedge in and be retained. More than Imm. is too obvious. Some patients have had a space between their central incisors all their lives and often in their old dentures. Discuss whether the space should be used; many patients will prefer to retain the space as they, their families and friends are used to it.
POSITIONING THE MANDlBLllAR ANTERIORS: It is very advantageous to position the mandibular anteriors at the chair, especially as a basis for good phonetics and esthetics, and as an additional check for vertical dimension. 1 .
The mandibular anterior teeth should be positioned to favor the mandibular ridge and should, except in rare cases, be positioned inside the labial flange.
2.
Start with an average horizontal and vertical overlap of 2mm. If planning a low cusp or flat posterior tooth arrangement, keep the vertical overlap angle very small or at 0". Insert the trial denture and instruct the patient count from 60 to 70 rapidly. Observe the relationship of the centrals during the sibilant sounds. Ideally, the mandibular centrals should be slightly distal to the maxillary centrals with a l - 2 mm. clearance. If too much or too little " S" clearance is apparent, it is necessary to re-set the teeth or increase or decrease the vertical dimension. 1-2 rnm Get an opinion from an instructor. The mandibular centrals are moved labially or lingually if indicated.
3
77V
4.
Esthetics: It is rare to observe natural mandibular anterior teeth that are straight and even. The artifical teeth will look more natural with the use of rotations, embrasures, variation of long axes, diastemas, and incisal abrasion. Note that the smile line is a reverse of the upper arch and curves downward slightly from the centrals to the canines. DO NOT use these concepts without the patient's consent.
EVALUATION OF ANTERIOR 'TEETH: Do not give the patient a mirror and say "how do you like them" but check the esthetics and phonetics (solve the problems yourself). Move the teeth, lengthen, shorten, rotate, push out or in, and work with the set-up until you feel they're reasonably correct. Walk away a few steps and turn quickly and ask the patient to smile. Do you see the correct amount of maxillary and mandibular teeth when smiling and speaking, are the teeth too long or too short, etc.? After you are completely satisfied with the set-up, have the instructor come to the unit and criticize and make suggestions. When both you and the instructor are pleased with the results, give the patient a mirror and ask for comments. Don't ask for criticisms as that is what you will get. Remember that the patient will usually dictate, and rightly so, the final arrangement. RE-SHAPING OF ANTERIOR TEETH: Be certain the teeth are acceptable to the patient. The teeth may be re-shaped to improve esthetics but this must be done carefully. Also, this is best done at the insertion visit as the teeth may move during processing. Use a rotary instrument to improve some of the characteristics by careful and judicious grinding. This can include grinding the incisal edges to simulate wear, reshaping the outline to enhance ferr~ir~ine or masculine characteristics, widening the embrasures to separate the teeth, and other effects to avoid the perfect outlines of artificial teeth. DO NOT grind teeth if you are uncertain of patient acceptance. -SET-UP OF ANTERIOR TEETH IF NOT DONE AT THE OPTIONAL VISIT: The anterior teeth are set-up using the same guidelines and principles described in the previous section. 'This is not difficult if the wax occlusion rims have been correctly contoured and have accurate markings for the mid-line and other guidelines.
ARRANGEMENT OF POSTERIOR TEETH: 1.
For cusp teeth, arrange the teeth in centric occlusion as the teeth cannot be balanced until after the protrusive record. See the next page for a Densply photograph of a typical cusp arrangement, set in bilateral balance. Also, study the diagram below:
2. Flat teeth (monoplane teeth) are set on a level occlusal plane with no compensating curve. "Three-point" balance is achieved with the use of balancing ramps {page IOI), after the protrusive record. See page 95 for photograph of a monoplane set-up. IMPORTANT: The stone casts of the patient's previous dentures are very important aids; either to duplicate or to change as needed. It is quite difficult to set-up teeth in their correct spacial positions, even for experienced technicians. Correctly contoured and marked wax occlusion rims and stone casts of the previous dentures are a necessary for students and will be appreciated by your technician when in private practice.
TYPICAL SET-UP OF CUSP TEETH
THE COMPLETEDTOOTHARRANGEMENT INALL RELATIONS
Centric occlusion, buccal view.
Centric occlusion, lingual view.
Working occlusion, buccal view.
Working occlusion, lingual view.
Balancing contact, buccal view.
Balancing contact, lingualview.
Anterior view of completed tooth arrangement.
LINEAR SET-UP FOR MONOPLANE TEETH (balancing ramp not depicted)
..
Figure 6
MONOLINE@flat linear type tooth arrangement in centric occlusion, buccal view.
Figure 7
Centric occlusion, lingual view.
Working occlusion, lingual view.
Figure 8
Working o c c l u ~ i ~ n , buccal view.
Figure 9
Figure 10
Balancing position; buccal view.
Figure I I
Monoplane teeth are set on a horizontal plane and horizontal to each other.
A modified t w e of balance, called 3-point balance, can be acheived with a balancing ramp. See page 101.
lingual view.
FOURTH VISIT
TRY-IN TEETH, EVALUATE OCCLUSAL PLANE, CENTRIC RELATION,
VERTICAL DIMENSION, AND ESTHETICS
PATIENT'S ACCEPTANCE OF TOOTH ARRANGEMENT
POSTERIOR PALATAL SEAL AND PROTRUSIVE RECORD
Appointment sequences: I.
Finalize and make certain all preceding work is satisfactory: vertical
dimension, centric relation, and occlusal plane.
2. Locate and carve the posterior palatal seal. 3. Make a protrusive record and adjust the horizontal condylar guidance. 4. Obtain a final esthetic evaluation (patient, student and instructor). Materials needed: I. Bunsen burner 2. Alcohol torch 3. 1 stick stick Compound
4. Pink baseplate wax 5. Boley gauge and ruler
6. Cleoid and discoid 7. Hand mirror 8. Mouth mirror 9. Water bath 10. Wax spatula
Note: 'This is a very important visit. This manual should be on the
back bench and open at this section. Proper festooning is
essential before insertion of the trial denture.
EVALUATION OF OCCLUSAL PLANE: An occlusal plane that is not in harmony with the facial planes will never be acceptable to the patient, dentist or anyone else. This error will not occur if the wax rims were properly contoured, but the plane may be tipped from faulty handling or carelessness. Correction ,if needed, usually requires the re-setting of all or most of the teeth. The maxillary posterior teeth are removed and wax is added to re-create the correct planes. The correct occlusal plane is established and the teeth are reset, i.e., after evaluating O.V.D. and C.R.
EVALUATION OF VERTICAL DIMENSION: 1.
Remove the dentures and record a new rest position, measuring the distance between with reference dots on the nose and chin with a Boley gauge.
2. Place the trial dentures and have the patient count from 60 to 70. 3.
Observe the sibilant sounds closely and determine if thespace between the maxillary and mandibular central incisors is too large or too small; 1-2 mm is needed for a good "S"sound. Listen carefully for posterior tooth contacts as this may be an indication of excessive OVD.
4.
Observe the face at rest and when swallowing. Can the patient close and swallow comfortably or is it an effort to close around the teeth? The lips should be closed, touching lightly, not bunched together, possibly a closed OVD, and never separated, possibly excessive OVD.
5.
Give the patient a hand mirror and get an opinion of face length. Ask the patient if the jaw should close more, or does it feel or look like the jaw is closing too much.
6
Record the occlusal vertical dimension (OVD) and compare it with the rest record taken previously. The difference should be about 3 mm. Consider 4mm. for an elderly patient or if the ridges are poor. Younger patients can usually tolerate 2mm. In most cases, more OVD will provide better esthetics.
7. Compare the OVD of the trial dentures with the old dentures' OVD, using the reference points and Boley gauge. Generally, the OVD should be either the same or slightly (I to 2 mm.) more than the old dentures. Get an opinion from an instructor if you are planning to change the vertical dimension.
8. To sum up, the patient should be able to close comfortably with no lip or facial strain and should not have tooth contact when speaking or at rest. A change of I mm. ca.n be made on the articulator by moving the incisal pin 2 mm. If 2 mm or more is required, a new centric relation record is necessary as a hinge-axis face-bow was not used.
97
EVALUATION OF CENTRIC RELATION: The centric relation record is probably the most important of all jaw relations, and is often incorrect due to shifting bases, mounting errors, etc. A quick way to verify is to soften green stick compound in a water bath (1400F), adding a 3-4mm. layer over the posterior teeth. Guide the patient into the CR position so the record is as thin as possible but without tooth contact. Make certain the maxillary trial denture is retentive; use adhesive, if necessary. Remove carefully, chill in water from drinking fountain, and place back on the articulator. Loosen the condylar guidances. If the record does not seat or does seat but ,the condylar elements are not touching the stops, there may be an error in the original mounting or the new record was incorrect. Consult with an instructor. CORRECTION OF AN INCORRECT MOUNTING: I.
A recording error requires a new CR record. If the OVD is excessive, it will be necessary to remove the mandibular posterior teeth, to provide space for the recording material. Place the teeth back on cardi~gwax, in order, as the teeth to identify. If the OVD is correct or deficient, dry the are often diffic~~lt mandibular posterior teeth and cover with a very thin layer of Vaseline (to facilitate removing the compound later).
2. Vaseline the maxillary posterior teeth, liberally, and insert the trial denture. Make certain it is retentive; use adhesive if necessary. 3.
Add an even amount of water bath softened compound to the posterior area, so the material is 2-3mm. higher than the occlusal plane.
4.
Place the mandibular trial denture in the mouth and have the patient bring the jaw into the most retruded position at the established vertical dimension. Use the anterior overlap as a visual guide or pre-measured dots on the nose and chin. Remove and chill. Examine for adequate bilateral contacts and clear tooth indentations.
EVALUATION OF ESTHETICS: It is vewimportant to check the following: I.
Color and mold of anterior teeth - confer with patient.
2. Midline symmetry - bisect the face with a piece of dental floss. An off center midline is distracting and a serious error. 3.
Length of the anterior teeth - evaluate with the patient at rest, speaking and smiling. Important - check the "smile line" for a pleasing effect.
4.
If the anterior teeth touch when speaking either the maxillary teeth should be moved labially, the mandibular teeth moved lingually, one arch or the other raised or lowered slightly, or any combination. There is also a possibility that the O.V.D. is excessive (obtain an opinion from your instructor).
5. If a spouse, family member, or friend is in the waiting room, get him or her involved.
Important: Denture adhesive is often used in this visit. Don't forget to remove the adhesive before replacing on the cast. Otherwise, the adhesive will adhere to the cast and will harden. Removal is difficult and may result in marring of the cast.
THE PROTRUSIVE RECORD:
'The protrusive record is made in order to record the horizontal condylar guidance. It is not an optional procedure. A practical method for making a protrusive record is as follows: I.
Place the trial dentures on the articulator.
2. Vaseline the teeth in the maxillary arch.
3. Place a roll of baseplate wax'on the occlusal surface of the mandibular teeth. Trim the wax so it is wide as the teeth and about 5 mm thick. Seal the wax to the teeth with a hot wax spatula. 4.
While the wax is still soft, move the articulator about 6 mm. into protrusive and close into the wax about 2mm. Indentations made by the teeth in the wax will provide a tactile guide for the patient. The intra-oral jaw movement must be about 6mm. Less than 4 mm. will not adjust the instrument and over 8mm. is beyond the range of the instrument. The jaw movement must be a straight protrusive with little or no lateral deviations.
5. Re-warm the wax with a Hanau torch without destroying the tooth indentations. Insert to place. Have the patient protrude the jaw and slowly close about 2-3mm. into the wax indentations. 6.
Remove and chill the wax in cold water (obtain from drinking fountains).
7. Release the centric locks and the condylar guidance locks. Raise the incisal guide pin. Place the trial dentures on the articulator.
8. The protrusive record is firrr~lyseated. Make certain the casts or distal area of the bases are not in contact. Move the condylar elements to a greater or lesser degree (upward or downward) until the maxillary teeth are firmly seated in the chilled wax record and the condylar elements will automatically adjust to the recorded horizontal plane. The latter will not occur if the condylar elements do not move easily and they should be clean and oiled.
Note: The horizontal angle will average around 300,i.e., if the occlusal plane is parallel to the upper member. If there is a negative reading or one side is 5 or more degrees different, there is probably an error and the record should be repeated. Use the higher angle of two records. It is now possible to arrange the teeth in bilateral balanced occlusion, i.e., simultaneous contact in all excursions. Monoplane set-ups: A balancing ramp can now be placed to provide "3-point" balance for flat occlusions. This is done by adding a soft wax, such as red carding wax or Bosworth green wax to the area behind the second molars. Overbuild the wax so you have about an excess of 1 rrlm in height. Move the articulator in protrusive and lateral excursions and the wax will create a slightly curved surface, when processed. will help maintain the posterior aspect of the denture in place during function. The illustration below shows the balancing ramp, which can be wax as described above or a tooth (usually the second molar). Dentists who don't like the concept feel that the upper denture can be shifted forward and the lower backward, and prefer a flat plane thoughout.
THE POSTERIOR PALATAL SEAL: Objective and rationale: A complete maxillary denture requires a posterior seal that will maintain the denture during movements of the soft palate. The maxillary denture is primarily retained by negative atmospheric pressure. This requires an intact peripheral seal. After processing, the volumetric shrinkage is as high as 7%. This causes the resin to lose contact from the critical posterior area with a resulting loss of seal. A correct posterior palatal seal will maintain firm contact and thus the peripheral seal. Position: The seal must end posteriorly on soft tissue and be of sufficient depth to prevent air from entering under the denture during functional movements that includes singing, sneezing, coughing, etc. It should extend and compress the soft tissues about 2 mm. lateral to the ptergyomandibular raphae and passing over the hamular notch, running medially and distally to the junction of the hard and soft palate and about 1 mm. posterior to the vibrating line.
Sketch A: Width and Shape
A. 0. C. D. E.
Ptergyomandibular raphae Tuberosity area of ridge Hamular notch Greatest width of the posterior palatal seal: about 4-5rnm. Mid-line: 3 to 4 mm.
CAST CARVING PROCEDURE: The patient must be present when the posterior palatal seal is carved as it is necessary to palpate the seal area. It must be done before 'the denture is sent to the lab for processing. The most convenient time is at the trial denture visit. 1. The cast, if properly boxed and ,finished, has a definite posterior finish line for the denture and the record base must end on this line.
2.
Mark the junction of the movable and immovable tissue with a dot in the middle of the palate with an indelible stick. Insert and examine the trial denture in the mouth to determine the position of the dot relative to the posterior border. Adjust the posterior border of the trial denture so that it goes from the rr~iddleof the hamular notches to the midline junction of the movable and immovable tissue.
3.
If the record base is too long in any area, reduce with a resin bur. Then place the record base on the master cast, and score a line with a sharp instrument, keeping the sharp instrument against the record base. This score line on the master cast is the posterior end of the denture.
4.
The indelible line should still be visible; palpate the tissue anterior to the line with a large end of the ball burnisher. Record in millimeters on the distal land area of the cast the five estimated depths of the compressible tissues (see Sketch B on next page).
5. Depth: The seal is about 112 mm. deep lateral to and over the pterygomandibular raphae. As it broadens to the palatal portion, the depth should be no greater than 2 mm. but not less than 1.5 mm. These depths are reduced .5-1 mm. if the seal areas are less compressible. Width: The seal should completely fill the prehamular space, 1-2 mm. in width. After it leaves the prehamular space it will broaden out to approximately 4 to 5 mm. and narrow at the midline to about 3 to 4mm. These are maximum dimensions as there is no advantage to making the seal wider or deeper. For depth control, a #8 round bur that is about 2 mm. in diameter is used.
'THE MAXILLARY WAX-UP:
NOTE: This is the last chance to change or add a posterior palatal seal. Failure to do this step will result in a faulty maxillary denture and time consuming procedures that must be followed to correct the mistake after completion of the denture. The labial portion of the maxillary denture base replaces the resorbed tissue. The greater the loss of bone, the thicker the denture base, but if the ridge is large the labial base must be very thin. The wax is contoured to support the lip. The form should be natural in appearance.
INCORRECT1 b o thick )
CORRECT
All peripheries are rounded and a properly made impression should include the complete peripheral roll (beginning at the junction with the land area). The peripheral roll will determine the thickness of the denture borders but the final thickness will be decided when the finished dentures are inserted. Note: It is useful to take another look at the borders of the old dentures. If the facial support was adequate, it would be prudent to modify the new dentures so the borders have a similar width.
CORRECT
I
INCORRECT
I
The thickness of the labial surface should be determined by the peripheries and lip support. Since the lip is mainly supported by the anterior teeth, the labial is usually quite thin. Extra wax may be required in some cases to support the lips and cheeks but overdoing this may interfere with normal muscular activity and movement of the mandible. "Plumbers" are thick areas of the denture base that are used to support (plump) sagging lips and cheeks. Heavy plurr~persare uncomfortable and should be avoided. They are a poor substitute for plastic surgery but are occasionally used; especially if they were on the previous denture. The palate thickness averages 2 to 3 mm. Finishing a rough and uneven palate is very time consuming. Remove the entire palatal portion starting 4mm. away from the teeth and the laboratory technicians will replace this with a special form so the denture can be finished with the correct thickness. The over-all thickness of the denture base may in some cases be determined by muscular strength of the patient. A denture base on a petite elderly lady could be thinner and lighter than for a 50 year old rugged male. Rugae: Each person has rugae of some sort in the anterior area of the palate. There is some controversy concerning its use or value. When placed in a denture these hard irregular ridges usually cause concern and old denture wearers may demand their removal. When used the rugae should be flattened and subtle (not patients, it is usually best to prominent and sharp ridges). For experienced dent~~re examine their old dentures and use a similar palate form. If rugae are indicated, make certain they are requested on the Laboratory Instructionsform,
Proper instrument angulation produces correct inter-dental papillae and contour.
After the wax is removed from the cervical area of the tooth a large scraper is used
to reduce the remainder of the wax.
Continue to contour the denture base with wax spatulas. An instrument with a
spoon-shaped end is the best type of instrument to use for contouring a denture
base. Most of the contouring can be done with a No. 7 wax spatula.
--.
The torch is used to smooth wax and not to contour wax or make it flow. When the denture base has been properly carved and contoured, flaming will round the marginal gingival area, the inter-dental papillae, and form a natural gingival cuff. A little wax may flow onto the tooth while the denture base is being flamed. This flash is removed with a sharp instrument to redefine the gingival cuff. During this final trimming only the wax which has flowed onto the tooth is removed. Do not attempt to re-contour the wax or re-flame after the filial trimming around tlie teeth. When using resin teeth, it is of the most utmost im~ortanceto remove all wax from the teeth, facially, inter-proximally, and lingually. Otherwise, denture base material will adhere to the teeth causing a poor esthetic result, and making finisl-ling procedures difficult. It is often advantageous to use dental floss in-between each maxillary and mandibular tooth to remove excess wax and create a natural appearance. A denture base with a stippled effect simulates natural gingivae and prevents unnatural light reflection from the denture base. Stippling the base denture base is done by first lightly flaming the surface of the wax. The wax base is then struck repeatedly with a stiff toothbrush. The bristles, being held in a vertical direction, produce many small indentations in the wax. The wax base is then flamed in a light and fleeting manner with a Hanau torch to smooth out the rough edges caused by the toothbrush. The result is a stippled surface, which when transferred to the complete denture, produces a natural appearance in a patient's mouth.
I
NOTE: The denture base should be stippled only where the base will show when the patient talks and smiles. A stippled or over-carved denture base is not as hygienic as a smooth polished base. Also, stippling interferes with the cohesionadhesion effect on retention as the lips and cheeks drape over the polished surfaces. A highly stippled and over-carved denture will look good in the hand but they will not enhance retention and hygiene - use only where needed. The placement of the stippling can be specified in the laboratory authorization.
REMOUNT RECORD FOR MAXILLARY DENTURE: Objective: To make a simple record to remount the maxillary denture after it is finished in order to preserve the same face-bow relation that was recorded before processing. With this procedure, a new face-bow transfer is not necessary. Remove the mandibular denture, cast and mounting from the articulator. Obtain a paper cup and cut the bottom out using scissors. Make 8 cuts about I inch long and an inch apart around the borders of the cup. Place the large end over the mandibular mounting ring. Turn the outward edges of the upper portion. Vaseline the occlusal surfaces and the incisal edges of the maxillary teeth. Make a mix of plaster and pour into the cup over filling out onto the edges. Bring the top element of the articulator into centric, the teeth indenting the plaster, indexing the occlusal surfaces and incisal edges. When hard, remove and preserve for later use. UTILIZATION OF THE COMMERCIAL LABORATORY: A commercial laboratory will process, polish and correct any occlusal processing errors. The dentures must be turned in with the wax-up finished and ready for flasking. The laboratory will wax in the palate in order to avoid the frequent error of palates that are too thin or too thick. The palates will be removed but the lingual area adjacent to the teeth must be finished. The palatal seal must be completed. Note: All resin processing requires 3 working days, e.g., work turned in on a Monday will require Tuesday, Wednesday and Thursday for completion and a Friday delivery. Processing for the last 4 weeks of a trimester will require 4 working days, e.g., work turned in on a Monday will be returned on the following Monday. All resin processing goes to the lab only on Mondays, Wednesdays and Fridays so one day must be added for work turned in on Tuesdays and 'Thursdays. I. Fill out a lab requisition with the patient's name and number, your name, color of acrylic resin, smooth or rugae palatal form and any other special instructions. 2. The lab prescription must be signed by the instructor and starr~pedby the cashier. Two-thirds payment is necessary before the cashier will stamp the lab authorization.
-
3. 'The patient's social security number is typed on onion skin paper. The lab technicians will place the number on the underside of the denture while packing the case. This required bv California State law. 4. Give the waxed-up dentures on the articulator to one of your Gold Window Clerk with the completed Laboratory Instructions form: 1
UNIVERSITY OF SOUTHERN CALIFORNIA
SCHOOL OF DENTISTRY
LABORATORY INSTRUCTIONS
j
......................................No .............
Patient .......................................ChartNo ........
Typeofcase ...................................................
Student
I
........................... Time .................
............................ Time .................
Date turned in Dateneeded
ACRYLIC RESIN:
SPECIAL INSTRUCIIONS
LigM LigM Red
Bluish Pink
High Impact
&tra Dark
2s-
.........................................
. ..F.IN.I.s.M.. LABIA.L.ELANGL..WRR%..T.H IN.. .. ...~.~.~H..L.\.C~M.T:..S.~J.I!.FIL~.H.G .....................
PAYMENTS 213 COMPLETED
................................
Cashier's stamp or sipature
READY TO PROCESS. ......................................
Signature
GROUP ROOM #
II
EXAMINATION OF DENTURES UPON RETURN FROM LABORATORY:
Usually some niodifications will be needed. Use your finger (no gloves) and feel the insides of the dentures. Frequently, there will be sharp projections that would irritate the patient, especially upon insertion and removal. Laboratory technicians are reluctant to change anything on the tissue side of dentures. These sharp areas have little or no effect on support or retention. Also, examine the borders for excessive thickness, especially the anterior flanges, and trim if indicated. REMOUNT CASTS AND REMOUNT PROCEDURES:
Objective: To construct casts to facilitate remounting the dentures on the articulator. Attempting to mount dentures without plaster casts takes more time and usually results in a weak mounting. Materials used : 1. Plaster 2. Vaseline 1.
3. Course purrrice 4. Periphery wax
After the dentures are polished, block out the undercuts using wet pumice or periphery wax. Place a thin layer of Vaseline over the inside and borders of the dentures.
2. Make a rr~ixof plaster and pour casts for both the maxillary and the mandibular dentures. The remount casts should be about the same size and have about the same dimensions as the master casts. Also reduce all the land areas at the vestibules as they might interfere with complete seating. After the casts are trimmed, remove all the purrlice or wax. The dentures should fit solidly on the casts with no tipping or rocking. 3.
Remount the maxillary cast on the articulator using the Dixie cup record. a. Place the Dixie cup reniount record on the mandibular member of the articulator. b. Place the maxillary denture on the Dixie cup index. Vaseline the mounting plate and the upper member of articulator.
c. Mix plaster and secure the maxillary remount cast to the upper member of the articulator. d. Smooth the plaster before it hardens, using your wet finger. Note: The mandibular denture and cast will be mounted after the C.R. record at the insertion visit. CARE OF THE DENTURES AFTER POLISHING:
Acrylic resir~must be kept moist or it will dry out and warp. A habit should be developed of placing all acrylic resin appliances in a container of room temperature water immediately after polishing and kept in water until inserted in the patient's mouth.
INSER'TION OF FINISHED DENTURES
Materials Needed: 1. Hand mirror
I
2. 3. 4. 5. 6. 7. 8.
Cotton rolls Blue periphery wax Pressure disclosing paste Pan with cold water Sharp knife Sticky wax Vaseline
9. 10. 11. 12.
Pressure disclosing paste Resin burs Horseshoe carbon paper Water bath at 1400 F.
Note: Make this appointment for 1:30 p.m. as the entire afternoon is needed for this visit. Do not insert dentures on Thursdav or Fridav. The patient may develop sore spots or other difficulties over the weekend add the result may be a very negative opirlion of the new dentures. Most post-insertion problems can be corrected if treated e m .
I.
Make certain to collect any balance of payment remaining. Do not, under any circumstances insert a denture unless the total amount is paid. There is an old adage that a dollar bill between the gums and denture results in a poor fit!
2. Examine the inside of both dentures carefully, both visually and manually, and remove any small bubbles or sharp projections.
3. Insert the mandibular denture FIRST. The soft tissues of the ridge will be defornied by the old dentures and the new dentures require at least 15 min. for tissue accommodation. If the maxillary denture is placed first, it may up lying on the patient's tongue - not a very good beginning for this visit! This occurs as the soft ridge tissues are often distorted from the ill-fitting old dentures but will later adapt to the new dentures. Also, it is easier to insert the mandibular denture first as there will be more space without the opposing denture. Then insert the maxillary denture. 4. Ask the patient if there are any areas of discomfort.. If reasonably satisfactory, place a cotton roll on each side at about the first molar area and instruct the patient to maintain a firm closure for lominutes. The patient should not be allowed to close with the new dentures as the occlusion has not yet been corrected. A malocclusion would result in uneven pressure and unwanted tissue displacement. 5.
Check the adaptation with pressure disclosing paste: a. Dry each denture with tissue and air syringe. Adjust each denture separately. b. Brush on a thin even layer of paste over the entire tissue surface of the denture. Use a disposable brush. c. Wet the denture with water. Never place a dry denture in the patient's mouth, and especially with a layer of paste. If the patient has any areas of dry mucosa, the paste will adhere to these areas, and give you an incorrect record. d. Insert and press firnrly (around 20 Ibs. of force - the average force of mastication) with even pressure on the 1st molar areas. e. Remove and examine. Carefully reduce any pressure areas with resin burs. Use No. 8-10 round burs for narrow areas in the mandibular denture. Pay strict attention to the following areas:
1. Mandibular denture: a. The mylohyoid ridge area. b. Lingual areas in the first bicuspid area. c. Overlying sharp bony spicules. 2. Maxillary denture: a. Incisive papilla. b. Mid-palatine suture area Note: of the above areas should be slightly over-relieved. Blow the grindings and moisture off with an air syringe, and add more paste and repeat until the layer of paste is fairly even.
g.
Ask the patient if there are any areas of discomfort. If so, the dentures may need more adjusting.
h.
Do not attempt to achieve a perfectly even layer of paste as too much denture base may be removed. Remember that ample opportunity will be available during future adjustments.
6. Do not attempt to evaluate any border extensions at this appointment with the heavier paste (Sorenson's) ur~lessan obvious correction necessary. It is usually better to assume the borders are fairly correct and check for peripheral irritations after 24 hours. Patients often cannot locate sore areas with accuracy and border irritations can usually be located visually and then located precisely with Sorenson's paste.
I.
Insert the maxillary denture firmly. If the retention is inadequate, apply a thin, even layer of denture adhesive. Assure the patient that the fit will be better after the denture "settles in" and also the denture can be re-fitted (if necessary).
2. Instruct the patient that you wish himher to close on the back teeth but not to touch. You will tell when to stop. Look at the space and hopefully see an even amount of distance between the teeth. If the teeth are closer together on one side it can be assumed that the side has premature contacts.
Note: It is necessary to remount and equilibrate the occlusion no matter -
whether it seems acceptable or not. The occlusion may look good but it is impossible to see the lingual areas and the important relationship of the maxillary lingual cusps to the mandibular fossae.
3.
Flame soften a 113rd stick of green corr~poundand a 3 mm layer over the lower posterior teeth. Temper in the water bath and at the same time make the compound smooth and even with your lightly Vaselined finger. Re-flame lightly with an alcohol torch with a brush flame (pin point is too hot) and temper again. All this is done quickly.
4
Seat the mandibular baseplate firmly and hold in place with your index fingers on the buccal flanges and thumbs lightly on the chin. Guide and instruct your patient to close with repeated closures (tap-tap) until the record is about 1-1.5 mm thin. If the teeth touch, the dentures will shift and the record is useless. If too thick, the C.R. position will change a little after the record is removed on the articulator and the teeth are in contact.
6. Remove, chill and trim the excess compound with a very sharp knife. Remove the maxillary denture and examine both dentures with the record. Make certain there is no contact between the tuberosities and pads that would cause tipping and a useless record.
7. Ct- ill again, insert and check for even contact. Watch carefully for even seating of the maxillary cusps. If the maxillary denture moves up a little, it is probably due to soft tissue resiliency. If the denture shifts laterally, even slightly, the record is probably faulty. Try to make a record that meets your standards and also get an opinion from an instructor. If the record is unsatisfactory, make another record. Don't take a chance with a questionable record as mounting and equilibration procedures are time consuming.
8. With a satisfactory record, remove both dentures. Remount the mandibular denture to the maxillary using the previously made plaster mounting cast. Note: If you did not make the remount cast it will be very awkward to create a mounting and cast at the same time and the mounting is always weak and unsatisfactory.
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9. Remove the compound record, loosen the pin and look at the occlusion. The occlusion may look good or not good. In either case it is advantageous to take another C.R. record. A second C.R. record is completed and placed back on the articulator. If the teeth fit into the compound index, the original record has been verified. If not, the mandibular cast is re-mounted using the second record and this occlusal relationship is again evaluated. Sometimes it is very difficult to record a repeatable C. R. and a 3rd record is needed. Note: Never remount the maxillary cast, always the mandibular (to preserve 'the face-bow relationship). EQUILIBRATION OF OCCLUSION:
'The purpose of the remount and selective grinding is to eliminate all areas of interference between the maxillary and mandibular teeth, so that each tooth bears the proportionate occlusal load. A well balanced, smooth functioninq occlusion is probablv the most im~ortantsinqle factor for successful dentures. PROCEDLIRES: 1. Adjust the articulator to the proper settings.
2. Use blue carbon paper for marking centric contacts and red for excursive movements. No. 8 low speed round bur and a Melite bur for larger areas.
3.
Restore the vertical dimension first. A lateral shift of a tooth or a protruding tooth will increase the V.D.O. Do not grind the cusp tips unless the cusp is high in all excursions, but rather reduce the fossae or inclined planes.
4.
Obtain even contact in centric occlusion: Tighten the incisal pin at the correct opening for these dentures so the vertical dimension will not be altered. The fossa is reduced unless the high cusp is premature in working, balancing and protrusive positions. Reduce the teeth until the lncisal pin is touching the incisal guide table and uniform contact exists on all the posterior teeth. The anterior teeth should not touch in centric occlusion and only lightly in excursive movements (see drawing on next page).
1
The illustration (center) shows the areas to be ground (shaded) to close an open V.D. and obtain centric occlusion. CENTRIC OCCLUSION
5.
Working relation: Loosen 'the centric locks and use the horseshoe paper. BULL rule: If an interference exists on the working side, reduce either the lingual slopes of the upper buccal cusps. or the buccal slopes of the lingual cusps.
WORKING
Adjust the balancing relation at the same time:: Reduce the buccal slope of the upper lingual cusp and lingual slope of the lower buccal cusp. The lower buccal cusp is a centric cusp so try not to reduce the cusp tip.
BALANCING
7. Adjust the protrusive relation: If the anterior teeth have heavy contact and especially if the posteriors have no or little contact, reduce the lower anterior teeth as grinding the upper teeth might compromise the "smile line" or esthetics. If the contact is heavy with no anterior space, the usual interferences are on the distal inclines of the upper teeth and mesial inclines of the lower teeth.
8. Rough teeth are uncomfortable and tend to "drag" the dentures during bruxing movements. Resin teeth are easily polished with wet pumice on a small rag wheel. Don't over polish or you will reduce the cusp tips.
9. Monoplane occlusion is adjusted by first using a glass slab and sandpaper for the upper denture and establish a flat plane. Thereafter all adjustments are made on the lower denture. First obtain an even distribution of centric contacts. Then smooth the eccentric movements. Polish. Make certain that all the pumice has been removed and the dent~~res are very clean. Be very careful not to get pumice or debris in any of the working parts of the articulator.
INSTRUCTIONS TO THE PATIENT: 1.
Always insert the mandibular denture first and then the maxillary. This is especially necessary for well extended mandibular dentures.
2.
ALWAYS comment on how well the dentures look and restate that the dentures will feel and function better in time. It is also necessary to make the patient. aware that some future discomfort is to be expected and follow-up adjustments and maintenance are always required.
3. Discuss the fact that mastication is always a problem for new denture wearers and often for experienced ones. Recommend that chewing food simultaneously on both sides will greatly reduce tipping, and greater chewing forces are possible. Demonstrate this using cotton rolls. 4.
Give the patient the handout, "How To keep Your Dentures Clean" (sample on next page). If the patient does not read or speak English, translate it if you can or obtain help from another student or staff member.
5. Appoint the patient in 24 hours for an examination and adjustment.
U.S.C. SCHOOL OF DENTISTRY DEPARTMENT OF REMOVABLE PROSTHODONTICS
HOW TO KEEP YOUR DENTURES CLEAN
Your dentures must be kept very c l e a n t o prevent t h e f o u l i n g o f food p a r t i c l e s and t h e overgrowth of b a c t e r i a .
It i s b e s t t o brush t h e dentures
a f t e r each meal and before r e t i r i n g .
A s p e c i a l d e n t u r e brush i s a v a i l a b l e a t d r u g s t o r e s t h a t w i l l reach i n t o a11 p a r t s o f t h e denture. Use any m i l d hand soap b u t DO NOT use an abrasive soap o r c l e a n s e r as t h e l a t t e r can r u i n t h e f i t o f t h e denture. h a l f f i l l e d w i t h water.
Clean t h e denture o v e r a s i n k bowl t h a t i s This w i l l prevent breakage i n case t h e denture
s l i p s from your f i n g e r s . - T a r t a r tends t o c o l l e c t on t h e d e n t l ~ r ej u s t as i t d i d on your n a t u r a l teeth. This can o f t e n be removed by soaking t h e denture i n w h i t e vinegar f o r an hour o r more. Another problem i s s t a i n which comes from smoking, coffee, tea, e t c . Many commercial preparations a r e a v a i l a b l e , b u t you can make y o u r own c l e a n s i n g s o l u t i o n by using:
1 teaspoon of k i t c h e n bleach (Clorox, Purex) and 2 teaspoons o f calgon (water s o f t e n i n g agent) i n 1 glass o f water. Soak the denture t w i c e a week f o r twenty minutes i n t h i s s o l u t i o n and t h e
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denture will be r e l a t i v e l y free from s t a i n , t a r t a r and b a c t e r i a . Do
N ot soak metal p a r t i a l dentures i n t h i s s o l u t i o n because t h e bleach w i l l r u i n t h e metal. The heal th'of y o u r gums and t i s s u e s t h a t support t h e denture i s very important. When c l e a n i n g t h e denture, i t i s advisable t o
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r i n s e t h e mouth v i g o r o u s l y w i t h p l a i n warm water o r a m i l d commercial mouthwash. A d a i l y g e n t l e massage w i t h a s o f t n y l o n toothbrush w i t h toothpaste i s very b e n e f i c i a l . Healthy o r a l t i s s u e i s b e s t obtained when t h e dentures are l e f t o u t a t n i g h t . The compressed gums must have r e s t f o r proper b l o o d c i r c u l a t i o n and r e p a i r . Some denture wearers must keep t h e dentures i n a1 1 n i g h t f o r personal reasons. I n t h i s case, t h e dentures should be l e f t o u t a t o t h e r times d u r i n g t h e day. For t h e b e s t r e s u l t s , f o l l o w y o u r D e n t i s t ' s advice i n t h i s m a t t e r .
When t h e dentures a r e l e f t
o u t o f t h e mouth, they a r e placed i n a c o n t a i n e r o f water as otherwise they may warp and t h e f i t can be changed, -
ADJUSTMENT APPOINTMENT:
Materials Needed: 4. horseshoe carbon paper I. mouth mirror 2. pressure disclosing paste(PDP) 5. resin burs 3. Sorenson's paste
I.
Check for peripheral overextensions which will have a red line or even an ulcerated area if severe. Do not reduce arbitrarily, but use Sorenson's paste. Do not try to check the entire periphery but only the one area that is sore. Use a layer of paste 1 mm. thick on the denture border which overlies the overextended border. Manipulate the lips and cheeks firmly.
2. Check for pressure areas on the ridge. Use a thin layer of pressure disclosing paste (P.D.P), held under heavy finger pressure. If the P.D.P. does not disclose any definite area, the irritation is possibly caused by occlusal prematurities, sharp bony spicules, mental foramen, etc.; consult with your instructor.
3. Check the centric occlusion with the carbon paper. Do this carefully and conservatively as it is very difficult to correct occlusal errors without a remount. Future occlusal problems may necessitate a new centric relation record and remount, so always retain the plaster mounting casts and the face-bow index until the case is satisfactory and completed. 4.
Evaluate the thickness of the flanges and make corrections if indicated. Be conservative as the face will relax and conform more with the denture contours in time. Assure the patient that these corrections can be made at a later date, as it is always best to wait for final settling and adaptation.
5. Polish the denture base and teeth well after any correction. 6. Make the second adjustment 48 hours later and repeat the above.
124
7. The next appointment (the third adjustment) should be about 1 week after the initial insertion but see the patient sooner if problems are anticipated or by patient request.
8. The denture may be graded for final credit after the case has been inserted and free of irritation for a minimum period of one week. The patient must be present to obtain credit. NOTE: It must be recognized that some patients will require a longer adjustment period, reline(s), re-setting of teeth, and possibly a re-make. Extra points will be given for all of the above (except adjustments). Keep in mind that we want the patient to be comfortable and satisfied, and we will do everything within reason to acl-~ieve that end.
Discussion of results with your instructor:
Get away from the hubbub of the clinic for a short session with your instructor (another day if necessary). This can be a non-threatening and very rewarding teachingnearning experience. Ask for an honest opinion of the over-all denture treatment, and very important the handling of the patient. Does heishe think you were friendly, kind, and considerate, or cool and aloof. What were your strong points and what areas need improvement. What was your own assessment? What areas do you feel reasonably adequate or do you need more instruction or just practice?
POST-INSERTION PROBLEMS: Unfortunately, many denture patient will have problems. These can be minimized by correct denture procedures and patient education. The patient must be made aware of the limitations of dentures and know that the burden of adjusting to these artificial devices rests largely with them. In some cases it is impossible to succeed when the physical and psychological handicaps are too great. Happily, most patients have adequate adaptive capacity to utilize denture effectively. THE FOLLOWING IS A LIST OF 24 POST-INSERTION PROBLEMS
WITH SUGGESTIONS FOR CAUSES AND CORRECTIONS:
Note: Many are rare and most are easily corrected.
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1. Looseness or instability a very common complaint!! a Upper drops when opening: 1. Most common - insufficint posterior palatal seal andlor short posterior border. 2. Poor border seal 3. Over-extended 4. Buccal flange too thick and interfering with coranoid process. 5. Over-extended in hamular notchh (crossing of pterygoid ligament that streches on a wide opening). b. Upper drops while talking or laughing: 1. Inadequate posterior palatal seal. 2. Poor seal 3. Occlusion not balanced c. Upper drops while singing: 1. Same as B 2. Stage fright or other factors may dry mouth and cause a loss Of physical factors of retention. d. Upper drops while whisling: 1. SameasB 2. Over-extension of labial and buccal frenums e. Upper tips on incisal pressure: 1. Pendulous tissue over ridge 2. Insufficient posterior palatal seal andlor short posterior border.
.
f.
Tipping or rocking of upper with pressure on posterior teeth 1. Failure to relieve torus palatinus (if present). 2. Lack of border seal in tuberosity region.
2. Lower rises when mouth is opened - very common complaint a. Most common reason - poor border seal. b. Over-extension of borders c. Retruded tongue (see Tongue Position, p. 16). d. Anterior teeth too far labial e. Posterior teeth too far lingual - tongue crowded. f. Lingual flange cupped out - traps tongue. g. Occlusion not balanced
Lower unseated during moderate tongue movements:
a. Poor border seal b. Lingual flange over-extended clearance for lingual frenum c. Ins~~fficent d. Occlusion not balanced Im~ortant: The patient must be informed that a denture wearer cannot sneeze, yawn, or make excessive tongue, lip, or cheek movements and expect the denture to stay in place. If these activities are necessary, the patient should use adhesives. Sore spots - a common complaint and are usually related to poor occlusion and inadequate fit, but other factors are: a. Inadequate denture base coverage andlor adaptation b. Entire ridge is red:; excessive vertical dimension c. Red spots on crest or near crest of ridge; occlusion not balanced Unfavorable denture base support: a. 'Thin, atrophic mucosa b. Hypertropic or pendulous soft tissues c. High, thin, knive-edged, flat, or irregular ridges d. Sharp bony projections e. Unrelieved tori
Unfavorable patient habits:
a. Braxing and clenching b. Constant chewing of gum, tobacco, pipe, or cigar c. Hot, spicy foods
e.
Eating foods that require forces that are beyond the tolerance of the supporting mucosa. Infections - local: a Bacterial (staph or strep); rare b Viral - apthous stomatitis; common (don't confuse witth denture Irritation). c. Fungus - Monilia albicans (Candidiasis); rare and only occurs in old and debilitated patients.
Allergies:
a. Denture base - rare b. Food or drugs - more common
Endocrine gland disturances:
a. Uncontrolled diabetes can result in sore spots and rapid bone loss. b. Thyroid and parathyroid disturbances can disturb calcium metabolism with soreness and resorption. c. Post-menopausal syndrome - frequent cause of sore spots, burning sensations, etc, and leading cause of denture failures in older women. Nutritional: many patients are low in calories, protein, calcium, iron, and Vit. B, C, and D. Note: Before grinding the denture consider some of the above possibilites as the etiology of the sore spot(s). 3.
Gacrainq: a. Psychogenic - starts in mind, very difficult to treat b. Stomatogenic - starts in body (usually dentures), treatable c. Dental causes: 1. Lack of retention 2. Poor occlusion 3. Insufficient or excessive palatal seal 4. Crowded tongue due to a thick palate or poor tooth placement 5. Excessive salivation 6. Excessive vertical dimension (often seen in new dentures)
4.
Feelina of sDace in upper denture; Due to a previous history of anterior traumatic occlusion with subsequent parasthesia of the naso-palatine nerves.
6. Phonetic ~roblems:Some patiens cannot speak clearly and probably never will, but dentures can interfer with speech, especially the "S" sound. 1. A clear "S" or sibilent sound is made by the propulsion of air through a channel formed by the lateral borders of the tongue curling upward and making contact with with the latetal aspects of the palate. The escaping air will create the important " S sound, i.e., if there is about a 2 mm anterior space.
If the space of the air channel is too small, the sound may be an annoying whistle. Some patients will whistle or not no matter the size of the space. Solution: Increase the passage of air (slowly) by removing some of the resin in increments behind the anterior teeth. If no improvement, try flowing some red carding wax in 1 mm increments, over the anterior and lateral palate to insure tongue contact. 2. If the air channel is blocked there may be a "shushing" or lisping sound . This is may be due to an excessive V.D.O. Solution: Before considering a remake at a reduced V.D.O., increase the size of the channel by thinning the anterior potion of the palate. 7. Can't eat most foods: 1. Poor muscular control many patients can masticate well no matter ifthe dentures are made correctly or not. 2. Patient expectations are too high; Patient expects to eat all the foods they enjoyed when they had their natural teeth.
Solution: Use more efficient teeth.
a. Make the lower food table as narrow as possible.
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b. Use lingualized occlusion. c. Use lingual bladed teeth - plastic denture teeth that have cast chromium cross-blades, 3 mm in height, that replace the lingual cusps of the upper teeth. The blades are set up so they occlude with the lower all plastic teeth. The occlusal scheme can be balanced, lingualized, or monoplane. These teeth require a special order and there is a $50.00 surcharge. Recommended reading: Payne. S.H.: A Posterior Set-Up To Meet Individual Requirements, Dental Digest, 47-20, 1941 (lingualized occl~~ion). 9. Loss of taste: 1. Mostly psychological as most of the taste buds are on the tongue. 2. Atrophy of taste buds common in geriatric patient.
10. Clickina while eatina or talkinq: 1. V.D.O. dimensiion excessive (inadequate interocclusal distance) 2. Premature contacts 3. Loose or over-extended dentures 4. Poor neuromuscular control
Solutions:
a. Re-mount dentures and equilibrate, reducing the V.D..O. b. Improve fit, if indicated, with reline or new denture. 11. Tenderness when swallowinq - over-extension of the disto-lingual flange. 12. Food under dentures: 1. Poor border seal 2. Inadequate posterior palatal sea.
3, Occlusion not balanced
13. Saliva under dentures - usually seen in new denture wearers: 1. Sameas14 2. Production of saliva under dentures usually lessens in time. 14. Dislodaement when drir~kina- same as 14
15. Droolinq at corners of mouth: 1. Closed V. D.O. 2. Excess salivation, usually in first time denture wearers. 3. Poor neuromuscular control 16. Excessive bulk: 1. Patienteducation. 2. If needed for a poor ridge, reduce where ever possible without loss of border seal. 17. Dull teeth: 1. Poor adptive capacity 2. Often a complaint when resin posteriors are used and the patient's
previous dentures were porcelain. 3. Limited effort by the dentist to provide more efficient teeth. 18. Cheek, lip, or tonaue biting: a. Cheek biting is the most common and is mainly due to inadequate overjet. Solution: Increase the overjet by reducing the buccal of the lower posterior teeth. Usually necessary in molar area only. b. Tongue biting - increase the overjet by reducing the lingual of the upper posterior teeth; usually the molars. c. Lip biting is not common and is usually due to poor tooth placement or poor neuromuscular control. 19. Halitosis - usually poor hygiene or can be a medical problem.
20. Drv mouth (Xerostomia): a. Radiation therapy b. Various drugs (list from patient) such as anti-depressants, and others. c. Geriatric degeneration d. Vitamin A deficiency e. Diabetes, choleras, or chronic nephritis f. Psychic tensions
21. Excessive salivation: New dentures, possibly psychic tensions. 22. Peculiar tastes - bitter metallic taste sometimes seen in menopause, worry, etc. 23. TMJ ~roblems- Arise mainly from muscle spasms of the muscles of mastication, mainly the masseter and terr~poralis.Usually seen in patients who have worn dentures a long time and the V.D.O. is greatly reduced. These circumstances may initiate the following: a. Pain in ear, joint and masseter area
b Head, neck, and back pains
c. Clicking or crepitus d. Ringing or buzzing in ear e. Pain when opening or chewing f Midline deviation when opening
Treatment:
1. Hot packs to joint or pain areas 2. Medication; muscle relaxants 3. Soft diet 4. Splinting; A 3-5 mm layer of self-curing resin is attached to the lower posterior teeth and adjusted intra-orally for even contacts. The patient is seen weekly and the splint is reduced or made higher (the patient will guide you!!), and the symptoms will usually lessen. When comfortable, the dentures can be relined or re-made, both at the established V.D.O. 24. Burnina sensation; Exact etiology not known and is usually prevelant in
females in menopause. It can be due to ill-fitting dentures, pressure on nerve foramina, or poor occlusiion, but correction of these factors rarely results in a cure. It has been initiated by extensive oral surgery. Voluminous articles and clinical reports have been written about this problem.
DENTURE ADHESIVES: Many patients have learned to wear dentures and enjoy good function. Unfortunately, there are probably just as many (actual numbers are unknown) who cannot manage even well made dentures and have difficullties with tallking, eating, and keeping them in place. Dentists have generally decried the use of adhesives as unnecessary and potentially harmful to the oral tissues. Another problem is that denture wearers tend not to return for relines or remakes, and will resort to adhesives. The later may create the necessity to use heavy layers and that may cause mucosal irritation and nearly always a change in the occlusion andlor O.V.D. There have been clinical studies by W. J.Tarbot, '80, and others and the findings have been that a thinlayer of adhesive and good oral hygiene does not result in musosal irritations. The studies also indicated that most of the patients had better function. The conclusions were that it was not the adhesives but the abuse of excessive use and the problem of not returning when the inevitable bone resorption occurs. Most dentists feel that m u s i n g adhesives is best but should explain how to use adhesives correctly and to return for an exmination when it's necessary to use heavier layers. TYPES OF ADHESIVES: 1 Adhesive powders - these are very popular as they are easy to use. The problem is the patient tends to dump an excessive amount into the denture,
with the thought that "some is good and more is better."
Show the patient how to hold the can of powder about 6 inches above the
wet denture and shake the can lightly so the powder will fall and create a thin,
even layer. Explain that only a thin layer is needed when the fit is proper, and
to return when more powder is needed for adequate retention.
2. Adhesive gels - these are dispensed in tubes and are popular as they are even easier to use. Again, the patient will use too much and will practically cover the internal areas.The gels tend to have a heavier body thaan powder and will displace the denture and affect the occlusion and V.D.O. Demonstrate that a small amount of gel in the molar areas and some in center of the palate and anteriior area is more than enough for upper dentures. Lowers will need some in the molar and anterior areas. Explain that in a short time tile gel will spread into a thin, even layer. As before, the patient must be told to return for an examination if the more gel becomes necessary. 3. Drugstore relining kits and liners - these have a great potential for harm to the mucosa and bone and their use should be strongly discouraged.
IMMEDIATE DENTURES
lmmediates are dentures constructed before all the teeth are extracted and placed immediately after removal of the remaining teeth. It may be a single denture, dentures for both arches, or overdentures. Removable partial dentures will not be done as immediates except for treatment RPD's. Complete irr~mediatedentures usually replace anterior teeth and occasionally bicuspids. Posterior teeth are usually removed prior to immediate denture construction and the ridge is allowed to heal so the patient will be more comfortable after the remaining teeth are removed. and the appliance inserted. Occasionally a posterior tooth or two are retained so the patient can continue to wear a RPD. ADVANTAGES: I. 2.
3. 4.
5. 6.
7.
The patient does not have to suffer the embarrassment of being edentulous and can quickly resume most duties and social contacts. The patient adapts to the denture more rapidly. Good speech and mastication are regained earlier. The denture acts as a splint, controls bleeding and aids healing. There is usually less pain. There is usually better ridge formation. It is easier to obtain a more cosmetic denture. Tooth position can be duplicated or modified. Vertical dimension is usually duplicated or can be changed if indicated.
DISADVANTAGES: 1. Correction of the fit and occlusion is needed at frequent intervals, necessitating more visits and a higher fee. 2. The arrangement of the anterior teeth cannot be evaluated until the dentures are inserted, i.e., no trial denture visit. 3. More difficult to make impressions with correct extensions. 4. Existing teeth may not be in correct centric relation andlor vertical dimension 5. Recall, maintenance, and relines are mandatorv so costs are higher.
IMPORTANT: ALL THE FOLLOWING PROCEDURES ARE SIMILAR TO THE ONES USED FOR COMPLETE DENTURES. REFER TO THE CHAPTERS ON COMPLETE DENTURES FOR MORE DETAILED INFORMATION. APPOINTMENT I:
PRELIMINARY IMPRESSION
Materials Needed: I. 2. 3. 4.
5. 6.
perforated trays rubber bowl and spatula plaster spatula mouthwash sponges mouth mirror
7. indelible stick 8. Vaseline 9. alginate impression material 10. water measure 11. artificial stone
Note : Obtain a green treatment form, "Immediate Denture Prosthesis Record". Sample on next page. I.
Select a correct alginate irr~pressiontray for the dentulous patient.
2. Correct the tray with periphery wax on the lingual border.
3. Complete the alginate impressions and pour in stone. 4.
Examine the casts carefully. Surgical corrections of the posterior ridge areas as bilateral undercuts, tori, sharp mylohyoid ridges, large tuberosities, etc., should be considered and planned now before any final irr~pression procedures. In some cases, these corrections can be made when the immediate dentures are inserted.
Note: Make certain the patient is aware that the immediate denture fee will include the temDorary relines but processed (don't call them permanent)) relines will be a separate fee.
'F.3
.
UNIVERSITY OF SOUTHERN CALIFORNIA SCHOOL OF DENTISTRY Immediate Denture Prosthesis Record Student .............................................................................
,:
.>
::,* ..,, : Ti,
No...............................Patient ......................................................................................... NO................................. :,:!:.
Assigned Instructol. .....1............................... .;............. No ................................Type of Case ........................................................................Fee .................................... .-
(Do not s t m t step 2 without an ~ s i g n e dinstructor)
.......................................
Remarks:
................................................. NOTE: All clinical and laboratory procedures must be signed by an -- 3,,
instructor. ALL procedures marked with an asterisk (*) must be signed by your assigned instructor.
I
Procedure Sequence
( Grade (circle)
I
t
I
.. "2. Preliminary impression-max 4 3 4 3 "3. Preliminary impression-man '4. Articulated study models. diagnosis and prognosis 1 4 3 5. Combination final impression(s) I Yes 6. Two-stage surgery Yes 7. Surgical template Yes 8. Preliminary cast(sl trimmed with . outline for iray (s). 9. Custom tray(s) fabricated 1 0. Border molded trav - max I I . Border molded tray - man * 12. Final Impression - max 4 3 * 13. Final Impression - man 4 3 14. Master cast(s) trimmed & indexed 15. Record base(s) with occlusion
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Initials
I I
Date
I
2
Instructor's Comments '.?
I
>.3
2 1 2 1 2 1
1
No I No No
I
I
-
--
2 1 2 1
rim(s) fabricated
* 18. Occlusal vertical dimension
* 19.
( 4 3.2 1 4 3 2 1
Centric relation recorded 1 20. Teeth selected 2 1. Anterior tooth arrangement 22. Posterior tooth arrangement *23. Examination of trial denture(s) 24. Protrusive record 25. Articulator set 26. Posterior palatal seal 27. Final set-up and wax-up 28. Laboratory remount 29. Denture(s) polished ':30. Placement: tissue adaptation 3 1 . '24 hr. tissue adaptation check 32. 48. hr. tissue adaptation and articulation check correct overt I occlusal discrepancies 33. 2 wk. post placement tissue . adaptation check remount. occlusal
I
1 1
I
I
1
1
4 3 2 1
I approve of the color, shape and arrangement of teeth in the wax denture(s).
t
1 4 3 2 1
I
I
I
1
I
I
4 3 2 1
34. Tissue conditioning 35. Reline (if indicated) 36. Final adaptation. polish and
articulation check
1 4 3 2 1
(Patient's Signature and Date)
. =..
FABRICA'TION OF THE CUSTOM IMPRESSION TRAY: I.
Outline the tray in pencil and have this important step checked by an instructor: a. 2 mm. short of the vestibule and more clearance for frenums. b. I mm. past the maxillary posterior border.
2. Block out any undercuts with wax (especially common in anterior area), but don't over-block. Use only pink baseplate wax. 3.
Adapt' one layer of baseplate wax over the teeth. Don't place any wax over the edentulous areas. Cut out the wax and expose the incisal edges of the right and left canines (or two other remaining teeth) to act as stops.
4.
Mix some auto-polymerizing tray material and roll out a wafer, using the thick side of the Rollette board. Adapt the resin wafer to the pencil line. Add a handle from the incisal of the central tooth area, which will make the tray handle around 25mm. from the vestibule to the horizontal extension. Make certain the horizontal extension of the handle is no lonaer or wider than 10 mm. from the incisal edge of the anterior teeth. After hardening, trim the excess tray material. Note: Alwavs place the handle in the center, using the midline andlor the labial frenum as guides. An off-center handle can result in an off-center impression.
5.
Remove all the wax in the area of the teeth. This is necessary as otherwise it would be difficult to insert and remove the tray during border molding.
APPOINTMENT II:
FINAL IMPRESSIONS
Materials Needed: 1. mouth mirror 10. large acrylic burs 2. pan with cold water 11. light-bodied polysulfide rubber 12. mixing pad and spatula 3. heater at 135" 4. compound or putty 13. indelible stick 5. alcohol torch 14. sharp knife 6. Vaseline 15. water bath at 135" 7. sponges 16. dental tape 8. moutliwash 17. rubber base adhesive 9. 3/32 twist drill or No. 8 round bur MANDIBULAR FINAL IMPRESSION: 1.
The tray is inserted and adjusted so it is underextended 2 mm.
2. The tray is border molded with corr~poundor putty in sections using the same procedures described under complete dentures, 'exceDt border mold the undercut areas last. The labial periphery is usually in an undercut due to the anterior teeth and/or alveolar bone. If this area is border molded early, the soft tissue can become bruised from repeated insertion and removal of the tray. 3.
Remove any undercuts in the compound with a sharp knife, especially in the area of the teeth. Remove any undercuts or sharp edges with resin burs.
4.
IMPORTANT: If the teeth have large caries, deep undercuts, fixed dentures, tissue bars, etc., block out the undercuts with soft wax.
5.
Paint the inside of the tray and borders with rubber base adhesive.
6.
Place a mix of liaht-bodied polysulfide material in the tray. Strive for even distribution of the material with no air entrapment and also cover the borders. Also, use a disposable PIP brush to obtain an even layer and cover borders.
7. Instruct the patient to rinse vigorously with a mouthwash. If the saliva is normal, the high viscosity of the rubber base will displace it. If the saliva is copious or ropy, pack the mandibular ridge area with gauze and remove just before placing the tray.
8. Carefully insert the tray and hold wtth firm even pressure. When the impression material reaches a firmer consistency (about 2 min.), instruct the patient to lick the lower lip, while you manipulate the lips with your thumbs. Hold the tray firmly in place with one hand and manipulate the cheek with the other. Repeat on the other side. The tongue and digital manipulations are necessary to prevent overextensions.
9. About 10 minutes is required from start of mixing time to final set. 'This will vary depending on temperature and humidity. Break 'the seal by retracting the lips and cheeks, and if needed, the use of the air syringe Remove with the help of the handle. 10. Examine carefully. Minor bubbles and flaws can be arbitrarily corrected on the the cast. If pressure areas, large voids or errors are evident, remove impression material and repeat. Remove the rubber base carefully and try not to disturb the border molding.
MAXILLARY FINAL IMPRESSION: 1.
Locate and mark the "ah" or vibrating line on the soft palate with an indelible marking stick. Insert the resin tray and the mark will transfer to the tray. Trim the posterior end of the tray to about 1 mm past the vibrating line.
2. The tray is adjusted so it is underextended 2 mm. (except the posterior border). Make certain the frenums are cleared adequately.
3. The tray is border molded with stick corr~poundor putty in sections using the same procedures described under complete dentures except the undercut areas are completed last.
Remove any undercuts in the stick compound with a sharp knife. Remove any undercuts or sharp edges in the tray resin with acrylic burs. Drill two holes with a 3/32twist drill near the posterior border. These will be used to place a loop of heavy dental tape to aid in the removal of the impression. Drill a 2 holes down the center of the palate 10 mm apart with a 3/32twist drill. Paint the inside of the tray and borders with rubber base adhesive. IMPORTANT: If the anterior teeth have large undercuts due to large cavities or bridge pontics, fill these in with soft wax. Otherwise, the impression will be very difficult to remove and loose teeth may even be removed with the impression! Another possible problem is tlie teeth on the master cast will be weak and may break. Place a mix of light-bodied polysulfide rubber base impression material in the tray. Strive for even distribution of the material, 3-4mm. 'thick, with no air entrapment and also cover the borders. Also, use a disposable PIP brush to obtain a more even layer and to cover borders. Instruct the patient to rinse vigorously with a mouthwash. Dry the ridge with gauze. If the vault is deep, place some impression material into the center of the palate, using a syringe. Carefully insert the tray and hold with firm even pressure. When the impression material reaches a firmer consistency, in about 2 min., begin to manipulate the lips and cheeks with the same movements as used when . making the impression. Facial grimaces and exaggerated movements by the patient can also be used. Whatever technique is employed must result in little or no changes in the border extensions. About 10 minutes time is required from the start of mixing time to final set. If less working time is required (gagger), a faster set can be achieved by adding 2-3drops of water to the final mix.
12. Break the seal by retracting the lips and cheeks. Remove with the help of the handle and a long loop of dental tape. 13. Examine carefully. Minor bubbles or flaws can be arbitrarily corrected on the cast. If pressure areas, large voids, or errors are evident, remove ALL the impression material and repeat.
BOXING, POURING. AND MASTER CASTS: 1. 2. 3.
Box in plaster-pumice. Vacuum mix and pour. Trim the casts and index.
FABRICATION OF THE OCCLUSION RIMS: Note: Occlusion rims for immediate dentures are fabricated with the same dimensions as for complete dentures except the resin adjacent to the teeth will be only on the lingual, with none on the buccal. For the mandibular baseplates, the lingual areas will be weak next to the teeth and are usually made thicker. 1.
Block out any undercuts on the casts with baseplate wax.
2. Apply Vaseline to the casts. 3. Mix some auto-polymerizing tray material and roll out a wafer, using the thin side of a Rollette board. Coe tray material is easy to use with less chance of breaking part of the ridge. 4.
Adapt the resin wafer to the cast covering the entire ridge area up to the teeth. With a warmed knife, carefully remove the excess around the teeth and along the land areas. Do each baseplate separately.
5. Finish the baseplates with an arbor band, acrylic burs, and pumice on the. lathe. Make the baseplates very thin over and buccal to the ridge so there is sufficient room for the teeth.
7.
Cut off the needed portions of the rolled wax rim with a warmed knife. Flame the underside of the rim portions and seal to place. The height of the rims should be 2 mm beyond the level of the remaining maxillary teeth.
APPOINTMENT Ill:
OCCLUSAL PLANE, VERTICAL DIMENSION, FACEBOW TRANSFER, CENTRIC RELATION RECORD, SELECTION OF ANTERIOR TEETH
Materials Needed: 1. mouth mirror 2. hand mirror 3. indelible stick 4. soft lead pencil 5. alcohol torch 6. pink baseplate wax 7. green stick compound 8. Fox occlusal plane 9. sharp knife
10. 11. 12. 13. 14. 15. 16. 17. 18.
Boley gauge flexible r ~ ~ l e r corr~poundheater face-bow assembly mold guide shade guide hot plate No.7 wax spatula pan of cold water
OCCLUSAL PLANE: 1. Insert the maxillary occlusion rim and check for patient comfort and adaptation. 2. Establish the height of the occlusal plane by evaluating the position of the
anterior teeth and the amount of inter-arch space. 3. Corrlplete the plane posteriorly by using Camper's line or the posterior teeth,
if not extruded. 4. Level the rim from the anterior aspect so it is at right angles to the long axis of the
head or parallel to the pupils of the eyes.
VERTICAL DIMENSION. REST POSITION AND INTER-OCCLUSAL DISTANCE: 1. Make a small reference mark on the chin and tip of the nose with an indelible
stick. 2. Record 'the occlusal vertical of the remaining teeth. Compare this with the vertical dimension of rest. The difference is usually 2-4 mm. In most cases, the same vertical dimension of occlusion is utilized, however, some cases require a change. Cons~~lt with your instructor. FACE-BOW TRANSFER: I. The face-bow transfer is similar to the procedure described under complete dentures
2.8 Cut four "V1-shapednotches in the maxillary rim (see complete dentures). 3. Add a 2-3 mm layer of green stick compound onto the face-bow fork. 'The maxillary occlusion rim is lubricated lightly with Vaseline and inserted. The facebow fork with the compound is seated over the anterior teeth (not too deep -incisal indentations only) and over the posterior portion of the rim. Make certain to line up the center line on the face-bow fork with the midline, which is usually, but not always between the central incisors. 4. Tlie rest of the face-bow procedures are exactly as described in denture section.. CENTRIC RELATION RECORD: 1. Lubricate maxillary occlusal rim with Vaseline. Place in the mouth, and secure
with adhesive if necessary. Try in the mandibular rim and make certain there is a 3 mm. space for the C. R. record. 2. Flame soften 113rd stick of compound and add a 3 rnrrl layer to lower occlusion rim. Temper in 135F bath and smooth compound with Vaselined finger.
3. Quickly insert and guide the patient into centric relation, closing until the anterior
teeth almost touch. This is necessary as contact of the natural anterior teeth will tend to guide the jaw into an anterior position. Note: If the vertical dimension is to be increased, closure of the jaw is completed at the desired new vertical level. 4. After the compound is hard, remove both rims. Chill the rims in cold water.
Remove the excess compound from the sides with a sharp knife. Also reduce the buccal width on lower so you can see the C.R. record better intra-orally. 6. Insert the rims and guide the patient to close in centric relation. Make sure there is simultaneous contact.
SELECTION OF THE ANTERIOR TEETH: I. Usually it is best to select teeth that are the same shade, size and shape (mold) as the natural remaining teeth. Sometimes a patient will prefer to have smaller and whiter teeth. Oblige them; it's their teeth! 2. Resin teeth are generally used there is rarely sufficient space for the pins needed to retain porcelain. Porcelain is sometimes used but care must be taken not to oppose natural teeth or gold.
SELECTION OF THE POSTERIOR TEETH: Use the same criteria as described in the complete denture section. Discuss with instructor. Usually cusp teeth are selected for immediate dentures but discuss this with your instructor as monoplane (flat teeth) are sometimes a better choice. MOUNTING THE CASTS: The upper cast is mounted with the face-bow record and occlusion rim. Use the C.R. record to mount the lower cast. Make certain there is no contact in the posterior area between the baseplates or cast, and debris is not trapped between the baseplates and the casts.
ARRANGEMENT OF THE POSTERIOR TEETH FOR A TRY-IN: 1. The articulator is set with an average condylar path of 30" and the condylar post at 15'. 2. The posterior teeth are arranged in centric occlusion. No attempt is made for balance in eccentric positions. 3. If any anterior teeth are missing, a try-in of the anterior teeth should also be included. APPOINTMENT IV:
CLINICAL TRY-IN
Materials Needed: 1. mouth rr~irror 2. compound heater at 140" 3. sharp knife 4. denture adhesive 5. Vaseline
6. 7. 8. 9. 10.
alcohol torch pan of cold water wax spatula baseplate wax hand mirror
1. The trial dentures are inserted and centric relation is verified by visual and manual inspection when the patient closes in centric relation. Make certain there is no contact of the baseplates in the tuberosity and pad areas. 2. If the teeth do not intercuspate or you can see or feel a slide, the mandibular posterior teeth are removed and a new centric relation record is completed. The mandibular cast is remounted, the mandibular teeth reset and another try-in is scheduled.
3. Protrusive record: On the articulator, softened baseplate wax 5 mm. thick is placed on the mandibular posterior teeth on each side. The centric lock nuts are loosened and the upper member is moved into a protrusive position. The protrusive movement should be about 6 mm. as less is inadequate for adjusting the articulator and more is beyond the range of the instrument. The maxillary posterior teeth are made to indent the wax 1-2 mm. The maxillary trial denture is inserted in the mouth after coating the posterior teeth with Vaseline. The -
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mandibular trial denture is tempered for a few seconds in the compound heater (wax side only) and inserted. Instruct the patient to open a little, move the mandible forward until lined up with the posterior indentations and then close 2-3 mm. into the wax. Remove carefully. Both trial dentures are chilled in COLD water and the horizontal condyle path is registered on the articulator. 5. Discuss with the patient any changes that you propose to make with the anterior teeth and make certain that the patient realizes that an anterior try-in is not possible. 6. Palpate the posterior palatal seal area for outline and depth, and record it on the cast. See the complete denture section for the technique of cast carving the posterior seal.
CAST PREPARATION AND ARRANGEMENT OF THE ANTERIOR 'TEETH By Dr. Phillip H. Reitz The current philosophy is to conserve as much bone as possible as we want the patient to have the best ridge possible, as long as possible. This translates into the concept of no or very conservative cast trimming (bone reduction). Work very closely with your instructor when moderate or gross cast reductions are necessary. The removal of the teeth and unsupported soft tissues that remain after extractions should be done on the cast. Because each patient is different, the preparation of the cast is different. Periodontal disease causes loss of alveolar bone and this must be taken into account when the cast is prepared. Each tooth is removed individually. The best method is to remove alternate teeth, e.g., right central, left lateral, right canine, left central, etc. As each tooth is removed, the denture tooth is placed in the same position so as to duplicate the occlusal plane and labial-lingual position. Sometimes the patient will prefer the teeth to be straighter or possibly inclined more labially or lingually. Discuss these changes with your instructor and the patient
The first step is to draw a line with a pencil, around the necks of the teeth, both labially and lingually. If carefully done it will be a double line, one on the tooth and the other on the gingival crest (Fig. 1 & 2). The next line drawn is on the labial at the height of the alveolar bone. Radiographs and periodontal probing depths are used to determine the correct levels (Fig.3).
Remove the first tooth. Carefully cut off the tooth including the pencil line on the neck but leave the line on the gingival crest. This should be a flat surface labio-lingually when finished (Fig. 4). It will be concave mesio-distally (Fig. 4a).
Draw a line across the center of the preparation at about the position of the former incisal edge (Fig. 5). Cut the labial surface from the center line to the bone height line. Again, this surface should be 'flat labio-lingually and concave mesio-distally (Fig. 6). The next alteration will be to round the sharp edge at center of the preparation.
flG. 4
0- 0 -)
flG. 4a
v5~
-I /-.7
I
\
LlG. 6
Place the selected denture tooth in the place of the original tooth. It is usually necessary to "hollow-grind" the gingival portion of the tooth. The study cast is helpful as a guide to tooth placement. Make certain the incisal plane is maintained and the labial-lingual position is the same as the original tooth. Lute the tooth to the baseplate with hard set-up wax. Use tinfoil over the cast if there is insufficient space. Lute the tooth securely as it will be necessary to remove the set teeth later. Repeat this procedure for each tooth, setting the teeth alternately. The last step is to remove the teeth that are attached to the baseplate and smooth the inter-proximals to blend the preparation previously made for each tooth (Fig. 7). Also smooth the lingual portion of the preparation to remove the gingival crest (Fig. 8). An alternative to connecting the teeth to the base plate is to make a labial core with plaster so that they can be returned to the correct position and then remove the teeth and smooth the inter-proximals.
FIG 7
FIG. 8
FINAL ARRANGEMENT OF THE POSTERIOR TEETH: Complete the posterior arrangement for balance in right and left lateral and protrusive. If necessary, reduce the anterior vertical overlap for protrusive balance by shortening the anterior teeth or increasing the horizontal overlap. Since this will change the esthetics, get advice from your instructor if a large change seems necessary.
COMPLETE THE WAX-UP: 1. If a ridge trim (alveoplasty) is indicated, it is accomplished at this time. 2. Consult with your removable prosthodontics instructor and discuss the amount of
cast reduction needed for a satisfactory result. Make arrangements to see an instructor in Oral Surgery. Bring the radiograms, study casts, and the waxed dentures and discuss how the ridge will be trimmed. If a large amount of alveoplasty is needed, the instructor should see the cast before it is trimmed. Also, discuss if a clear resin surgical stent is needed. 2. The wax-up is the same as a complete denture.
3. Make certain there is no wax on the teeth.
PROCESSING, CORRECTION OF PROCESSING ERRORS, AND FINISHING: 1. Processing and occlusal correction of processing errors will be done by a commercial laboratory. The denture(s) must be turned in with the wax-up finished and ready for flasking. The laboratory will wax in the palate to avoid the error of palates that are too thin or too thick. 2. Don't forget to carve in the posterior palatal seal. Request a stent if needed but only if necessary. Many surgeons find they have limited value and they are expensive to fabricate.
3. Fill out a requisition for the laboratory. Give the waxed-up denture(s) on the articulator to the Gold window clerk. Include the patient's social security number, typed on onion skin paper. The work will not be accepted without an instructor's signature and cashier's stamp. Note: The laboratory will require 3 full working days for processing all dentures and RPDs. For example, work turned in on a Monday will require Tuesday, Wednesday, and Thursday for completion and a Friday delivery. For the last 4 weeks of the trimester, processing will require 4 working days, e.g., work turned in on a Monday will be returned on the following Monday. resin processing goes to
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the lab only on Mondays, Wednesdays, and Fridays so one more day must be added for work turned in on Tuesdays and Thursdays. INSER'TION OF THE DENTURES: Materials Needed: 1. pressure disclosing paste 2. resin burs
3. articulating paper 4. denture adhesive
1. Insertion of immediate dentures is a responsibility of the Oral Surgery department but you will be present and may have an opportunity to assist or if the perhaps do the surgery. It is your responsibility to inform the instr~~ctor casts were trimmed heavily or lightly during tooth replacement. It would be very helpful to have the patient's study casts. The Surgery Department will not extract teeth and assist in the insertion of immediate dentures unless the proper signatures are on the clinical work progress sheet for immediate dentures. By proper signatures we mean that a faculty member has inspected and evaluated 'the dentures for polish, thickness of the flange, periphery, palate and has judged them ready for insertion. Further, all resin in the basal seating area of the denture such as socketed tooth projections, bubbles and old surgery scar irregularities must be removed and/or rounded. 3. If the immediate denture is to oppose a complete or partial denture in the opposing arch, that denture will be inserted before the patient is taken to Oral Surgery for the immediate denture insertion. 4. The Oral Surgery Department will make appointments for immediate denture
insertions&o on Monday, Tuesday or Wednesday, usually at 10:OO AM or 1:00 PM. An insertion on a Thursday is not recornmended ur~lessthere are special circumstances and a Friday insertion will not be done under any circumstances. Starts later than 10:OO or 2:00 PM require special permission from the attending doctor.
152
After the surgery is complete (and sutures often placed), return to the group clinic to check the fit of the denture. Pressure paste is not affected by saliva and blood. In fact, now is a good time to do this procedure since the ridge is usually still anesthetized and adequate pressure can be applied. The next day the ridge will be quite tender. The inside of the denture is adjusted until the P.D.P. does not show any excessive pressure areas. Don't try to obtain a perfectly even layer of paste it's not possible. 4. The occlusion may be checked with articulating paper. Cases that are carefully done require little or no occlusal grinding. For the patients well being, do as little as possible. If the occlusion is poor, it must be corrected at a later visit. 5. The dentures must be cleaned thoroughly. Dust the inside of the denture with a fairly heavy layer of denture adhesive. 6. Give the patient a copy of the form, "Instructions For Immediate Dentures Patients". Make certain the patient understands the instructions on the form (copy on next page). 7. The dentures are firmly seated and the patient is cautioned NOT to remove the dentures for a 24 hour period. Make an appointment for the NEXT day.
UNIVERSITY OF SOUTHERN CALIFORNIA
SCHOOL OF DENTISTRY
REMOVABLE PROSTHODONTIC SECTION
INSTRUCTIONS FOR IMMEDIATE DENTURE PATIENTS
1. DO NOT remove the denture for any reason. The denture will be
removed and adjusted when you return to the School ,the next day at your
appointment.
2. To reduce swelling, place an ice bag (or ice cubes in a plastic bag covered with a damp cloth) over the area of extractions for 10 minutes on, 10 minutes off, for the first two hours. For the rest of the day use the ice for 10 minutes of each hour. 3. You may take two aspirin compound tablets (Anacin, Bufferin, Empirin, etc.) or aspirin substitute (Tylenol, Anacin Ill, etc.) every four hours for pain as needed. You will receive a prescription if something stronger is needed.
4. You should take some food for an evening meal on the day of extractions. Scrambled eggs, soups, and/or ice cream can usually be managed without problems.
5. 'The next day after extractions, the denture will be removed by the student dentist and adjusted. You may rinse gently with warm water. The healing sockets should not be disturbed. Do not remove the dentures until the next day.
6. Unless instructed otherwise, on the second day after extractions the denture is removed and carefully washed after each meal. A brush and hand soap is used to thoroughly clean the denture. Rinse your mouth gently with a glass of warm water with a teaspoon of salt in it before replacing the denture. The denture should be worn at night for the first two weeks, after that time 'the dentures s h o ~ ~be l d removed at night before retiring. 7. A soft diet is indicated for the first 10-14 days, after that time harder food can usually be handled. Each person has different levels of sensitivity and manipulative skills. If it is painful to chew harder food, select somewhat softer food until there is better healing. 8. After 1-2weeks, the denture will be loose and a temporary liner will be used to improve the fit. As a rule, a temporary liner will be needed about every 2 months.
9. In about 6 months to one year, your denture will require a new processed liner. The cost of the temporary liners is included in your original fee. The usual charge will be made for a processed liner.
TWENTY-FOUR HOUR POST-OPERATIVE Materials Needed: 1. mouth mirror 2. pressure disclosing paste
4. articulating paper
5. mouthwash
3. acrylic burs 1. Carefully remove the dentures. Caution the patient that the removal may be
uncomfortable. 2. Give the patient some mouthwash and an extra emptycup. 3. Clean and dry the dentures. Check the adaptation again with the P.D.P. Also
check the borders for overextensions. Correct if necessary and polish smooth. 4. Check the occlusion again. Don't be too critical as swelling and edema may
make the occlusion appear faulty. 5. If the fit is poor, it may be necessary to line 'the denture with tissue conditioning material (Visco-gel) Obtain advice from an instructor. 6. The dentures are then cleaned and the dentures are quickly reinserted. Denture adhesives are usually needed for a few days. However, ca~~tion the patient that continued use of layers of adhesive will cause excessive shrinkage and will delay the mastering of the technique of using artificial teeth. Assure the patient that the fit will be improved as soon as the healing permits with a temporary reline. 7. Instruct the patient to use saline mouthwash four times a day (1I2 teaspoon salt in a glass of warm water} after each meal and before retiring). 8. Warn the patient about the potential damage of excessive use of adhesives and especially drug store liners.
9. Caution the patient to eat soft foods for about a week as heavy biting pressure
will delay healing. 10. Make an appointment in two or three days.
TWO OR THREE DAY POST-OPERATIVE: 1. Repeat the same procedures as above.
2. The occlusion can be further refined.
3. Compliment the patient on how well helshe is doing and answer any questions. 4. Sometimes the esthetic results are disappointing. Assure the patient that modifications can be made but at a LATER date. 5. If the fit is poor, confer with your instructor about the possibility of an early reline.
FIVE TO SEVEN DAY POST-OPERATIVE : Repeat the above procedures. 1. Repeat the same procedures. 2. Plan to see the patient the following week, but only if necessary. Many patient work or have other obligations and prefer not to return unless in pain or other problems.
3. Instruct the patient to call you if problems arise.
SIX WEEKS POST-OPERATIVE:
1 . Repeat the same procedures. 2. Do a chair-side reline if indicated but not before two weeks. Visco-gel will be used for most cases. Mix the material with 1 and 114 powder to one liquid so it's a little thicker than the usual 1 to 1 mix. Correct the occlusion with carbon paper.
3. Sometimes a hard chairside reline is indicated. Obtain help from your instructor
as the vertical dimension and centric relation can be grossly changed if careful procedures are not followed. Often just a small amount is needed in the area of recent extractions. Try to avoid relining the entire denture when using a hard material, especially a maxillary denture. 4. IMPORTANT - Remind the patient that the processed relines are not included in the fee and should be done no sooner than six months and no later than one year (closer to one year is best). If the mouth changes after the processed relines are inserted and the new relines are required later because of ridge changes, a new fee will be charged. Make certain the patient understands this policy as you will have the same problem in private practice. 5. If the dentures become quite loose before the six month period, plan on doing
another chair-side reline. Usually Visco-gel must be changed about every 2 month but varies depending on patient's diet and other variables. It may be necessary to also remount and correct the occlusion. Remember that you are responsible for the care of the patient until the processed relines are completed and checked off. If you will be graduating, you must confer with your group administrator and make certain the patient will have the proper care with another student. 6. You will receive separate credit and points for the processed relines. 7. The immediate denture(s) is checked off for credit after the laboratory reline has been completed, the denture have been remounted, and the patient is comfort able. Give treatment record to the department secretary for filing.
OVERDENTURES
An overdenture is a complete or partial denture that rests on mucous membrane and retained teeth. Teeth that might once have been extracted can frequently be retained by improving their crown-root ratio. For example, a common clinical situation is when most teeth have been extracted except the mandibular canines. These teeth, because of periodontal disease, have lost about two-third their bony support and have a very unfavorable crown-root ratio. Any type of removable partial denture, no matter what design, would result in early failure. However, if endodontic therapy is performed on the canines and the teeth reduced, the crown-root ratio can be greatly improved. A complete denture can be made that is supported by both teeth and ridge. The abutment teeth have a favorable prognosis as the forces are mainly vertical. The overdenture concept may be used complete, immediate or partial dentures. ADVANTAGES OF OVERDENTURES: 1. The forces transmitted to the soft tissue are reduced.
2. Retained teeth provide physiologic stimulation to maintain the alveolar bone around the roots. This is probably the most irr~portantadvantage. 3. When the teeth are drastically reduced and rounded, the potential for damaging horizontal forces is lessened considerably. 4. The cost is nominal, especially when compared to implants. 5. The vertical dimension is maintained by the retained suppo~tingroots. 6. The patient is not rendered totally edentulous, an important psychological consideration for some patients. 7. Denture stability and retention as well as support are increased. 8. Proprioceptors in the periodontal ligaments are an aid for all functional jaw movements. 9. In the event of loss of a supporting teeth, the denture alteration is simple and not expensive. 10. It is possible to obtain greatly improved retention with the use of an attachment.
DISADVANTAGES OF OVERDENTURES: 1. The total fee will be higher since endodontic therapy will be needed. This is offset somewhat by the elimination of the extraction fee. 2. There is a little more time involved in laboratory and chairside procedures, hence an appropriately higher fee is indicated. 3. The retained roots may weaken the denture.
INDICATIONS: 1. A patient who does not want to lose his remaining teeth that cannot be adequately treated with fixed or removable partial dentures. 2. A patient with a few remaining teeth whose mucosa, supporting bone or general health suggest a poor prognosis for complete dentures. 3. People with a bruxing habit (poor candidate for dentures) whose discomfort may be reduced by the support provided by a few teeth. 4. When natural maxillary teeth are to oppose a mandibular corr~pletedenture, every effort should be made to save a few mandibular teeth for denture support, to prevent the destruction of the patient's mandible. 5. When a maxillary complete denture will oppose mandibular natural teeth, an overdenture is the treatment of choice to preserve the maxillary bone.
CRITERIA FOR SELECTION OF SUPPORTING TEETH: 1. Periodontal condition: Select teeth with the least mobility, the best supporting
bone, and the healthiest gingiva. 'The teeth that are used most often are maxillary and mandibular canines. After the canines, the most useful teeth in order are: (1) molars and bicuspids, (2) maxillary central incisors, (3) maxillary lateral incisors, and (4) mandibular incisors. Periodontal pockets of about 4 to 5 mm. or more will require treatment before the denture is started. There must be a minimum of 3-4 mm. of attached gingiva. 2. Undercuts: Using a surveyor, determine the path of insertion and removal on the diagnostic cast. If the labial undercut of the selected tooth is too severe, consider using an adjacent tooth.
3. Location in the arch: Whenever possible, select the support teeth to protect the anterior ridge (canines or first bicuspids, or incisors, if necessary). It is best to have teeth on both sides of the arch but even one tooth is better than none. The ideal situation is to retain the canines and the first molars. 4. Proximity of supporting teeth: It is desirable to space abutment teeth as much as
possible to distribute the occlusal force and provide a broader supporting base. It is easier to maintain the health of the interproximal gingiva by avoiding teeth that are in mesio-distal contact to one another, especially crowded anteriors. 5. Economic considerations: The use of teeth that have already been successfully
treated with endodontics will reduce the total fee for the patient. Single-rooted teeth offer considerable savings in time as compared with treating three canals in molars. It is not necessary to use all the remaining teeth in the arch. It may result in too many undercuts and also the cost of all the endodontic and periodontic treatment. 6. Teeth with caries below the bone level are difficult to maintain and usually
cannot be utilized. If this type of support tooth is needed for success, periodontal surgery and crown lengthening may be feasible.
PROCEDURES: 1. The support or abutment teeth (don't refer to them as roots!) are carefully
selected. The best support teeth are cuspids, bicuspids, and molars. 2. Endodontic and periodontic therapy is completed on the selected support teeth. Sometimes periodontic surgery is performed at the insertion appointment.
3. Corr~pletethe usual procedures for complete denture fabrication. The procedure will be similar to an immediate denture 4. Outline the diagnostic casts for custom trays. Well-fitted trays are constructed.
It is desirable to perfect the borders of the trays by border molding with green stick compound or any other suitable material. Paint the tissue surfaces of the custom trays with adhesive. Complete the final impression with rubber base impression material and pour in improved stone. Occlusal plane and jaw relations: Well adapted base plates are constructed. Wax occlusion rims are attached to the base plates so the level of the wax is about at the tips of the canines. 'The occlusal plane is determined with the aid of a Fox Occlusal Plane. Vertical dimension and centric relation are recorded using the occlusion rims and green stick compound. The correct shade is selected by matching the remaining teeth. The correct mold is obtained by also matching the remaining teeth (or perhaps an old RPD), but modifying the shape, size and color of the teeth, if requested by the patient. The master casts are mounted on a suitable articulator. All the posterior teeth are set in C.R. and also include any missing anterior teeth. 6. The trial dentures are tried in and checked for V.D.O., C.R., mid-line, & esthetics.
Laboratory procedures: The a.lpport teeth on the cast are reduced with a straight fissure bur to the level of about 3 mm above the free gingival margin. Then the teeth are carved with a sharp knife so 'they are cone-shaped. Resin denture teeth are trimmed so they fit snugly against the support teeth and in the same position as the original teeth. Only resin teeth are used; not porcelain teeth. Finish the set-up. A final wax-up is completed and the dentures are processed.
7. INSERTION: Reduce the support teeth to a 2 mm level above the free gingivae (Fig A & B), using a high speed fissure bur.
r_:
DISTAL
MESIAL
Fig. B Fig. A 8. The final shape (like a flat-top cone) is made with diamond stones. 'The tooth surfaces are finished very smooth (to reduce plaque retention) with Shofu Greenies and Brownies. The root canal is filled with amalgam. The final crown height should be about 2 rnm, measuring from the proximal gingivae be reduced to the gingival level as this (see Fig. C & D below).The teeth must will result in a proliferation of soft tissue over the teeth, with continuous bleeding and discomfort.
Fig. C
Fig. D
162
9. ABUTMENT RELINES: In about a week, more or less, and after the occlusion
has been corrected with a remount, the final relationship is made between the support teeth and soft tissues, so the support is about equal between the teeth and residual ridge. This step is very important:, especially for lower dentures. a. Use a No 8 round bur and remove about 1-2 mm of resin from the indentations of the support teeth. b. Make a small mix of tooth-colored, self-curing resin (Jet). c. Wait a bit for the mix to thicken and ad to the indentations so they are half filled. d. Coat the crowns and adjacent gingivae with Vaseline. e. Wait until the resin loses its gloss and has less flow. f. Seat very firmly and have the patient close to maximum biting pressure on cotton rolls. g. Remove when hard. Remove any resin that flowed into the gingival crevices. Remove any resin that flowed over the pink base as it is excess and will irritate the soft tissue. Remove about 0.5 mm from the area of free gingivae. 10. It is very important to see the patient every 6 months. Good oral hygiene must be constantly taught and re-enforced at each visit, If bone resorption occurs, a repeat of Step 9 is indicated as the roots will be the major support with little help from the residual ridges. This may be determined by your tactile sense, excessive rocking, or by patient observation. It should always be done if the teeth feel "sore". 11. Give the patient a Rx for Gel-Kam, a 0.4% stannous flouride gel, with instructions to place one drop of the gel in the overdenture indentations, after brushing the teeth and cleaning the dentures. Also, give your patient a copy of "Instructions For Patients Wearina Overdentures" (sample: next page). 12. 'The teeth may be shortening at future visits to improve the crown-root ratio. This is always done when there is excessive gingival recession and the teeth are clinically longer, and especially if the teeth show signs of increased mobility. This is difficult to do if the teeth have gold copings, and is an added reason for avoiding gold copings, but only if good oral hygiene can be demonstrated. Gold copings are indicated if the incidence of caries is very high and if needed for an attachment.
U N n m S m OF SOUTHERN CALlFORNIA
SCHOOL OF DENTISTRY
DEPARTMENT OF REMOVABLE PROSI'HODONTICS
INSTRUC'I'IONSFOR PATIENTS WEARING OVERDENTURES
You are very fortunate that some of your own teeth have been treated and retained so they can provide a much better denture. These teeth will often last many years but you must cooperate with the following: The teeth and gums must be thoroughly brushed, ideally after each meal and before retiring, but at the very least once in the morning and before retiring. Use a soft nylon toothbrush with any type of toothpaste. It is best to leave the dentures out overnight to give the teeth and gums a chance to rest and have natural cleansing action of the saliva. -GENE:
DECAY PREVENTION: After brushing the denture, each morning, place a drop of fluoride gel (Gel-Kam) in each tooth indentation. The Gel-Kam requires a prescription that mcry be refilled as necessary. This will aid in preventing decay of the remaining teeth. If the dentures are left in at night,
make certain they are clean and a drop of Gel-Kam is placed in the indentations.
CARE OF YOUR DENTURE: Use a soft toothbrush and any face soap or full-
strength liquid dish washing detergent to clean the denture. Abrasive type cleansers, like Comet or Ajax will ruin the fit of your denture. It is best to clean the dentures after each meal. To prevent or remove stch, the dentures may be soaked in the following solution overnight: One teaspoon of Clorox, two teaspoons of Calgon, one-hd glass of water. If the denture starts to accumulate calculus (the hard white material that also collects around the natural teeth), the denture can be soaked overnight in white vinegar, full strength. The vinegar will soften the calculus and it can be brushed off. The denture should never be allowed to dry out completely. Always soak in some sort of water solution when the dentures are not in the mouth. PGULAR INSPECTION: It is best to have your teeth and denture examined every six months. Gum recession and inflammation are common problems and this must be treated and controlled if the teeth and gums are to remain healthy. Also, the teeth may show evidence of decay so it will be necessary to treat them. There is no charge for this regular examination unless the denture needs a reline or the teeth or gums need further treatment.
Remember, if you want to enjoy the best benefits of your overdenture you musf: 1.
2. 3. 4.
5.
.
Keep the teeth and gums clecm. Keep the dentures clean. Use the Gel-Kamfluoride gel in the denture. Leave the dentures out overnight, if possible, Return for regular check-ups.
IMMEDIATE OVERDENTURE: Note:
Review the section on Immediate Complete Dentures.
1. Choose the teeth to be retained for support. 2. Remove all the posterior teeth. Sometimes some posterior teeth are retained to support partial dentures.
3. Complete the periodontic and endodontic treatment of support teeth. 4
Make the final impressions and all the usual immediate denture procedures to the point of preparing the master cast for processing.
5. Tooth preparation of master cast after trial denture visit: a. With the aid of radiographs and pocket depth measurements, mark the casts to predict the bone level after surgery. b. The teeth to be extracted are cut from the cast and the cast is trimmed to the predicted bone level. c. The support teeth are trirr~medso they are 3 mm higher than the free gingivae (to make certain the denture will seat without interference), as tooth contact is not needed for now and will be established in a few weeks with the abutment reline. ,
d. The supporting teeth are trimmed with a sharp knife so they are rounded and smooth. Place the denture teeth in harmony with the others. It is always necessary to hollow grind the teeth over the reduced support teeth. Complete the set-up, festoon, and turn in for processing. e.
Insertion: a. Before extracting any teeth, reduce the si~pportteeth, as described in previous section. Place the amalgam restorations to seal the canals. b. Proceed with the extrations and denture insertion. c. Adjustment procedures are the same as for complete denture. Note: Do not attempt too treat a patient for an immediate overdenture until you have reviewed the sections on overdentures and immediates.
RELINE AND REBASE 'TECHNIQUE
DEFINITION: Reline: To resurface the basal seating area of a denture with new base material to make it fit more accurately. Rebase: A process of refitting a denture by the replacement of all the denture base material without changing the occlusal relations of the teeth. A rebase is done if the denture base is in poor condition or is the wrong color. Laboratory technicians often call this procedure a "transfer" or "jump". NOTE: The clinical and impression procedures are the same for either a reline or a rebase. The procedure of "refitting" a denture base is a corrlmon service in any general practice. It is NOT an easy procedure and must be executed with skill and care. The most usual errors are tipping of the base, changing the occlusal plane, displacing the denture (usually anteriorly), increasing vertical dimension, and creating a malocclusion. The three keys to success are: 1. Correct diagnosis and treatment plan; the most important. 2. Reliable irr~pressiontechniques. 3. Remount after insertion and equilibrium of the occlusion.
DO NOT do a maxillary and mandibular reline or rebase at the same time. Ordinarily, it is too difficult to control the centric occlusion and vertical dimension unless they are done separately. Doing both together may be done only on the . advice and consent of your instructor and one must work very closely with that
instructor. The correct procedures are planned when the diagnosis is made.
NOTE: A reline-rebase procedure is not indicated if the teeth are excessively worn,
occlusal plane is incorrect, inadequate esthetics, teeth are related incorrectly to the
ridge, and the centric relation and vertical dimension are incorrect.
The reline procedure is most effective if the denture has fairly good borders but is
loose and may have a slightly closed vertical dimension.
'The mucosa should have normal color and a healthy appearance. If reddish or inflamed, tissue conditioning, such as leaving the denture(s) out for 3-4 days or using a thick layer of Visco-gel for a week or more.. USE OF VISCO-GEL FOR BORDER MOLDING AND THE FINAL IMPRESSION:
Materials needed: 1. 2. 3. 4.
Mouth mirror Indelible pencil Vaseline Visco-Gel kit
5. Sharp knife 6. Paper cups 7. cement spatula 8. Resin burs
material but is well suited for functional, closed VISCO-GEL is a tissue conditior~i~ia mouth relineirebasetechniques. It is a self-curing resin that remains soft and gradually polymerizes to semi-solid state in about one hour. Most of the tissue conditioning materials deteriorate in 3 to 7 days, but Visco-Gel will remain in good condition for weeks and sometimes months. It makes an excellent terrlporary reline for many situations, especially following an immediate denture insertion. Visco-Gel will flow into an area if the periphery is slightly short. If the area is too short, the soft Visco-Gel will slump since it is unsupported by the hard denture border and will appear ragged or thin. If the border is reasonably correct, the functional movements of the tongue and perioral structures will displace the material to the buccal, labial, and lingual and will result in smooth and rounded borders. Overextensions and pressure areas can be recognized by redness and irritation and must be corrected before the final impressions are made. Overextensions are possible, but unlikely to occur if the material is used at the proper consistency.
PROCEDURE: IMPORTANT: Remove &Iundercuts with the carbide resin burs from the inside of the denture, as otherwise the stone cast may be broken when separated later by the dental technician. 1. For border molding the peripheries, use the measuring containers supplied with the kit and mix 2 containers of liquid and 3 powders. Wait about 3 minutes or until the material has a putty-like consistency. Lubricate your fingers with Vaseline and roll out the Visco-Gel so it is 3 to 4 mm in diameter. Use a thinner roll for a thinner border and a thicker roll for a thicker or deficient border. 2. Dry the denture. Use the Visco-Gel lubricant (or Vaseline) on all the polished surfaces and teeth. Keep the lubricants 2 to 3 mm from the borders. Press the roll firmly on the periphery so the material can adhere to both the inside and outside surfaces. For the maxillary denture, bead the post-dam area, but DO NOT extend past the posterior border. For the mandibular denture, place the roll on the entire periphery but also do not extend past the posterior border of the pad, but bead the inside surface of the pad so the periphery is sealed. 3. Lightly lubricate the patient's lips. Insert the denture firmly. Have the patient bite
the denture to place. On the maxillary (only) push the labial flange posteriorly. This prevents the maxillary denture from being displaced anteriorly with a resulting faulty occlusion. Have the patient vigorously move lips, tongue, cheek and mandible for about 1 minute. Then engage 'the patient in casual conversation in order to obtain natural and functional movements. 4. Remove in 15 minutes or more; no less. The denture borders are examined carefully. The borders should have a round and smooth contour. If an area is ragged or thin, examine carefully for a possible underextension. The border seal and retention should be equal to a carefully border-molded impression. If the retention is poor, a determination must be made where the problems are as the final impression will not correct an inadequate seal. For the maxillary denture, the most common error is a short posterior border andlor the buccal tuberosity area. For the mandibular dentures, the usual errors are incomplete coverage of the pad and the buccal shelf area andlor a short lingual
flange. Deficiencies are corrected using a mix of the same consistency. Use one rr~ixof 3 powders to 2 liquid. A short posterior border requires an extension of green stick compound. 5. For the final impression, use a thinner mix, 2 liquids and 2 powders. Wait about 1 minute for the material to gain more body so it will pour slowly out of the paper cup (similar to maple syrup). If too sluggish, discard and make another mix. Seat as before and do the usual hand manipulations and patient movements. Encourage the patient to rinse and expectorate, and converse for 10 minutes (all to provide natural functional movements). Make certain the centric occlusion and vertical dimension have not been changed. 6 Leave the denture in place for at least 15 minutes. Remove carefully after
having the patient loosen the denture by blowing out the lips and cheeks with the lips closed, or use an air syringe in the depth of the vestibules. Handle carefully and examine for deficiencies. If any are present, mix another half portion and make 'the corrections. Wait another 10 minutes. Remove and trim any obvious overextensions with a knife or scissors. Replace the denture and allow the Visco-Gel to "cl.lreWfor at least 30 minutes. The patient can have water, coffee, tea, or a soft drink, but no food. Food particles can end up in the impression. Drinking liquids will require functional movements and will often provide even better borders. Remove carefully.
NOTE: It is sometimes advantageous to allow the patient to wear the denture with Visco-gel for 24 hrs. (not more) but a scheduling problem may not permit this confer with an instructor. When doing a maxillary and mandibular reline at the same visit, do the border molding separately and the final impressions separately. You must have written permission from an instructor (record in Therapy Record), who will also make certain of the jaw relations. 7.
Tell the Gold Room clerk the day before that you will be doing a reline so the laboratory can send someone for the denture. Do not box or pour the impression. Put the denture in damp Kleenex and handle carefully. The
denture is turned over to the Gold Room clerk for recording and processing with appropriate instructions. 8.
Insertion: a. The insertion procedures are the same as for a complete denture except a new face-bow transfer is required. b. When doing a maxillary and mandibular reline or rebase, the equilibration procedure is not done twice. 'The equilibration is performed when the second reline is inserted, or when a single reline is inserted. c. The adjustments and follow-up procedures are also similar to a complete denture.
DENTURE REPAIRS By Dr. Stephan Moradians FRACTURED DENTURES: Mid-line fractures are commonly seen on both maxillary and mandibular dentures. 1.
To repair the denture, the two halves are assembled together and denture is reinforced by attaching one or two old burs or match sticks to the occlusal surface of the teeth using sticky wax. The undercuts on the tissue side are blocked out using wax. The tissue surfaces are lubricated with a thin layer of Vaseline.
2. A cast is poured into the denture using quick-set plaster. After the plaster is set, the cast is trimmed and the pieces of denture gently removed. Caution must be exercised so the ridge areas of the cast are not broken. The cast is coated with Alcote and set aside to dry
3.
The edges of broken denture are trimmed about 1.5mm. from each side providing a gap of about 3mm (Fig. 1).
FIG. 1. A 3 mm. gap is necessary between the fractured edges.
4.
The pieces of the denture are re-assembled on the cast. 'The brush technique is used by alternate applications of monomer and polymer until the area to be repaired is filled. The area should be slightly over-filled to allow for finishing. 'The repair process may be hastened and porosity in the repair material prevented by using a pressure curing unit. 100°F water is placed in the curing unit so that it just covers the repaired area. Compressed air is introduced into the curing unit until it contains 30 pounds per square inch pressure. The denture is left for minimum of 10 minutes, removed, and polished.
REPLACING A BROKENTOOTH: Replacing a broken tooth is a relatively sirr~pleprocedure. The following technique provides satisfactory results although there are acceptable variations to this procedure. If the broken tooth is porcelain, the area lingual to the fractured tooth is reduced using a fissure bur, exposing the pins, (Fig. 2).
FIG. 2. The reduction must be large enough to accommodate the pins on the tooth without interference.
The fractured tooth and adjacent teeth are lubricated with Vaseline, then heated with a needle-point flame (Fig. 3).
FIG. 3. The tooth is heated with needle-point flame.
Heating the tooth softens the surroi~ndingresin. Note: If the tooth is resin, use a bur to remove it. The porcelain tooth is pushed out of the denture with any hand instrument. The mold of the tooth is determined by inspecting the ridge lap. The mold number is found on the ridge lap of most artificial teeth. If not present or unreadable, a mold guide is needed. The shade is determined with the use of a shade guide. A tooth identical to the one removed from the denture is selected and placed in position. Note: The rest of the procedures are the same for porcelain or resin teeth. A matrix of quick setting plaster is made of the labial surface of the new tooth and the adjacent teeth. 'The matrix is allowed to set, removed, and coated with Alcote. The matrix and the new tooth are re-assembled on the denture and held in place with sticky wax. Alternate applications of monomer and polymer using the brush technique are applied until the area lingual to the replaced tooth is slightly overfilled. The denture is placed in a pressure curing unit using the same method as the previous repair. After 10 rr~inutesthe denture is removed and polished.
