SEMINAR PRESENTATION ON
PREPROSTHETIC SURGERY DR. SEENA SAM 2ND YEAR P.G. STUDENT DEPT. OF PROSTHODONTICS AND CROWN AND BRIDGE 29.01.2014
INTRODUCTION A significant number of patients can never be made to use dentures effectively because of : bone atrophy soft tissue hypertrophy localized soft and hard tissue problems all of them
Various treatment methods to improve patient’s denture foundation and ridge relations are: Nonsurgical Surgical Combination of both
Nonsurgical methods
Rest for denture supporting tissues Occlusal correction of the old prosthesis Good nutrition Conditioning of the patient’s musculature
Characteristic of ideal denture bearing area
Adequate bone support.
Adequate firm soft tissue coverage.
No bony or soft tissue undercut or prominences.
No sharp ridges.
No high muscle or frenal attachments.
No presence of peripheral fibrous tissue bands to prevent proper seating No soft tissue hypertrophies on the ridges or in the sulci No intraoral or extraoral pathology Proper alveolar ridge relationship in all three planes
DEFINITION – PREPROSTHETIC SURGERY
Surgical procedures designed to facilitate the fabrication of a prosthesis or to improve the prognosis of prosthodontic care
[GPT- 8]
Preprosthetic surgery is carried out to reform/redesign soft / hard tissues by eliminating biological hinderness to receive comfortable & stable prosthesis.
Aims of preprosthetic surgery
To provide adequate bony tissue support for the placement of prosthesis Provide adequate soft tissue support ,optimum vestibular depth Elimination of the pre-existing bony deformities eg. Tori, promoinent mylohyoid ridge, genial tubercle Correction of mandibular and maxillary ridge relationship
Elimination of preexisting deformities. eg. epulis, flabby ridges, hyperplastic tissues Relocation of frenal or muscle attachments Relocation of mental nerve Establishment of correct vestibular depth
Specific indications for preprosthetic surgery include 1. Complete or partial edentulism secondary to early tooth loss. 2. Naturally occurring reduction of the residual bony ridge. a) Jaw atrophy b) Mucosal atrophy c) Interarch changes (vertical, anti post, transverse) d) Reduction of denture bearing area e) Muscle hypotonia f) Facial changes
3. Pain (not remedial by conventional prosthetic measures) due to: a) Mucositis (a burning discomfort of the mucous membrane) b) Neuropathy (alteration of sensation of the lips varying from objective/ subjective paraesthesia to anesthesia or pain arising from traumatized nerve trunks.) c) Local recurrent ulceration d) Temporomandibular joint pain
4. Dysfunction (not remediable by conventional prosthetic means) of: a) Mastication b) Speech c) Deglutition d) Temporomandibular joint dysfunction due to deficient dental occlusion
5. Replacement of lost tissue following disease/trauma a) Orbital prosthesis. b) Obturator which replaces the missing jaw or orbit. c) Craniofacial prosthesis. d) Enhanced gag reflex / excessive palatal sensitivity. e) Allergy to conventional prosthetic materials. f) Phobia to normal prosthetic appliances.
CONTRAINDICATIONS 1. Underlying systemic diseases, e.g. cardiovascular, metabolic/haematological 2. Insufficient quantity of bone 3. Inadequate quality of bone (sclerotic/ osteoporotic)
4. Unfavourable inter arch relations (vertical, horizontal, transverse) 5. Adverse mucosal conditions (quality/quantity) 6. Adverse skin conditions and congenital remnants
7. Pre-existing pathology 8. Adjacent dentition 9. Local anatomy (inferior alveolar nerve, maxillary sinus, floor of nose, tongue size)
10. Psychological/ psychiatric disorders 11. Parafunctional habits 12. Opposing dentition/jaw 13. Additional bone grafting
14. Previous radiotherapy 15. Poor oral hygiene 16. Poor patient co-operation/compliance 17. Heavy tobacco smoking
Common conditions that require surgical correction prior to CD construction Soft-tissue abnormalities: 1. hypermobile ridge tissue, 2. soft-tissue interferences, 3. hypertrophic labial and lingual frenum, 4. prominent buccal frenum, 5. papillary hyperplasia, 6. epulis fissuratum
Osseous abnormalities: 1. ridge undercuts, 2. prominent mylohyoid and internal oblique ridges, 3. bony tuberosity interference, 4. sharp spiny residual ridge, 5. tori and exostoses
Retained dentition: 1. unerupted teeth, 2. retained roots
Preprosthetic surgical procedures
Alveolar ridge correction
Alveolar ridge extension
Alveolar ridge augmentation
ALVEOLAR RIDGE CORRECTION
Bone surgeries Labial alveolectomy Primary alveoplasty Secondary alveoloplasty Excision of tori Reduction of genial tubercle Reduction of mylohyoid ridges Maxillary tuberosity reduction
Soft tissue surgeries: •Removal of redundant crestal soft tissue •Frenectomy – labial & lingual
•Excision of epulis fissuratum & palatal hyperplasia
ALVEOLECTOMY
Surgical removal or trimming of the alveolar process Trimming done with roungeur or round bur and smoothened with bone file Use in the presence of sharp margins at interseptal or labiobuccal alveolar ridge Too much bone loss will result in poor
Single tooth alveolectomy
Simple Alveoloplasty
Refers to surgical recontouring of the alveolar process. Primary alveoloplasty always done at the time of multiple extraction or single extraction. Minimum amount of alveolar bone resorption occurs if after simple extraction ,digital compression of the
Intraseptal alveoloplasty – dean’s alveoloplasty with repositioning of labial cortical bone. Used in maxilla
Used to reduce gross maxillary overjet To reduce the volume of cancellous bone , maintaining stress bearing cortical bone intact Not require for raising mucoperiosteal flap
Carried following extraction of anterior teeth immediately. Maintain periosteal attachment to the labial plate of bone. It will reduce buccal undercut or labial prominence without reducing the height of residual alveolar ridge. Best long time result Indicated in cases , in which the adequate bone height exists.
Indications 1.Multiple extraction
2.Early initial post extraction period.
Steps
1.removal of bone followed by 2.repositioning of the labial cortical bone
Technique
Teeth should be extracted avoiding trauma to the labial cortex. Interdental septal bone is cut from canine to canine region with the straight fissure bur attached to surgical handpiece or with rongeur.
With the same bur ,vertical cuts are made only in the labial cortex at distal end of the canine extraction sockets bilaterally without perforation of the labial mucosa in the dean’s technique.
With periosteal elevator /osteotome placed in the base of the canine socket bilaterally, labial cortex is fractured. Digital pressure is used to compress the fractured labial cortex into the palatal direction.
Labial and palatal plate will come into approximation with each other
Interrupted continous suturing is carried out.
Obwegesser’s modification for Obwegesser’s interseptal alveoloplasty Indication Gross max.overjet.( when compression of the labial cortex is not sufficient)
After cutting the interseptal bone ,an inverted cone vulcanite bur is used to widen the socket. With small bur ,horizontal cuts are made at the base of the extraction socket in the labial and palatal cortices
Vertical cuts then made bilaterally in both the labial and palatal cortices in the area distal to the canine socket. With digital pressure,both the labial and palatal cortices are compressed together and sutures are given. Immediate denture delivery is planned ,used as a template to check for any pressure points.
Alveoloplasty with post extraction healing
Crestal incision is taken not to tear the mucoperiosteal flap, but the reflection Side ways separation with the periosteal elevator will help the smooth reflection Sharp areas or large undercuts should be trimmed with rongeur and suturing done.
Elimination of unfavourable undercut
Usually done in the mandibular lingual aspect (genial tubercle , sharp mylohyoid ridge prominence.) Seen in patients wearing old dentures, due to resorption over the years, the denture become unstable
Reduction /resection of the genial tubercle
Are bony attachments of genioglossus muscle. Are seen on the crestal level on the lingual aspect.
Technique
Crestal incision is made from the lower canine to canine region , after infilteration of the LA
No reflection of flap done on the labial side Full thickness flap is reflected to expose the genial tubercle
Excision of tubercle is done by rotary instruments Smoothening can be done by a bone file Irrigation should be done before suturing
Reduction of mylohyoid ridges
Done with IFAN block. Crestal incision taken in the posterior ridge region. Mucoperiosteal flap reflected on the lingual side to expose the medial surface of the mandible at the mylohyoid ridge region.
Tissue from the floor of the mouth and lingual mucoperiostium are protected by inserting the flat blade of the tongue depressor The reduction of the mylohyoid ridge is carried with osteotome or round bur ,after dissecting mylohyoid fibres away.
Bone is smoothened with bone file. Soft tissue flap is returned back and the complete lingual vestibule checked with digital pressure for any sharp areas.
After complete smoothening sutures are given.
Excision of tori Indications
Large torus ,filling the palatal vault. Large torus extending beyond the postdam area. Ulceration or traumatisation or hyperkeratinisation of the overlying mucosa.
Deep bony undercut.
Interference with function.
Psychological consideration. Food lodgement
Technique
Under LA – ( bilateral grater palatine and incisive nerve block)
A-P linear incision in the midline of the palate. Y’ shaped releasing incision at one or both the ends of the incision.
Two mucoperiosteal flaps raised with periosteal elevator from the midline sideways.
Retraction sutures placed on both the flaps to minimize the exposure. Division of the torus into the multiple segments should be done with the bur.
Small pieces removed with chisel and mallet. Continous over and under type suturing using fine absorbable suture material. Prefabricated acrylic stent or splint or iodoform pack can be given to prevent heamatoma.
Mandibular tori removal Technique IFAN block is given.
Incision over alveolar ridge in lower premolar region. Mucoperiostial flap is raised
Make a purchase point or groove with bur on medial aspect of the torus.
Cleavage taken with a osteotome. Smoothen with round bur or bone file. Irrigate band suture.
Maxillary tuberosity reduction and exostosis removal Technique Under infilteration or PSA nerve & GPN block
Crestal elliptical incisions from tuberosity to premolar area. Periostium is reflected and tissue present b/w the crestal incision removed with chisel mallet or bur.
Soft tissue surgeries
Removal of redundant crestal soft tissue - eg . enlarged tuberosity, enlarged retromolar pad. Denture granuloma or hyperplasia.
To reduce this elliptical incision taken on either sides of the tissue .
Excision of epulis fissuratum.
Sharp excision
Electro-cauterisation
Cryosurgery
Laser excision
Palatal papillary hyperplasia.
Supra-periosteal excision.
Frenectomy Indications High attachment of frenum.
Ulceration at the frenal attachment a due to overuse of the denture
TECHNIQUE
Crosss-diamond excision. Base of the frenum at the alveolar crest is grasped with the hemostat and incision is taken below and above the hemostat. Surgical defect created by excision of fibrous bands.
Lingual frenectomy Indication: Tongue tie •
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Technique Bilateral lingual nerve block Submucosal dissection done on either side . Dissection of genioglossus muscle and suture it.
RIDGE EXTENSION PROCEDURE
Vestibuloplasty or sulcoplasty
It is a deepening procedure of vestibule. labial vestibular procedure transpositional flap vestibuloplasty or lip switch procedure
Indications Used when patient has a bone ht of 15mm or more in the ant region
Techniques Kazanjian technique (1924) oldest technique
use mucosal flap from the inner aspect of lower lip. Carried out in premolar to premolar region.
Procedure submucosal dissection is done and directed inferiorly to remove muscle and connective tissue attachments
Raised mucosal flap is adapted to the new vestibule and Suture is done
Godwin’ s modification (1947)
Mucosal incision in inner aspect of lip is longer than the proposed vestibular depth Labial periosteal margin is sutured to the incised lip mucosa. Stent is placed.
Clarks technique
Supraperiosteal flap on the inner aspect of lip leaves a raw surface on the bone covering the inner lips surface Incision started labial to the crest Supraperiosteal dissection is done along the labial surface till the vestibular depth
Edge of the mobilized flap is pushed into the new vestibular area and held in position by sutures
Alveolar bone is covered by periosteal layer
Obwegesser’s modification
Similar to clarks method except the area of alveolar bone with its periosteal attachment covered with split thickness graft.
Advantages Covers the bone and ensures fast healing Less bone loss and scarring .
Lingual vestibuloplasty Indication
In case where mylohyoid and genioglossus close to the alveolar ridge.
Trauner’s technique
Incision is done from 2nd molar to 2nd premolar region Supraperiosteal dissection is done Instrument passed below mylohyoid muscle and separate it from bony attachment Fixation of mylohyoid muscle to new desired vestibular depth by sutures.
Caldwell’s technique
Here mylohyoid muscle superficial fibres of genioglossus muscle pushed inferiorly. Rubber tubing placed in the lingual vestibule and flap is held in position by sutures
Obwegesser’s technique Lingual vestibuloplasty + buccal vestibuloplasty Edges of buccal and lingual flaps are raised and sutured below the inferior border of the mandible.
Skin graft is placed over the entire alveolar ridge. Acrylic stent or denture placed and fixed to mandible with circum mandibular wiring.
Submucosal vestibuloplasty technique Indication Shallow vestibular depth with good underlying bone height and contour. Technique Vertical midline incision is made in the labial vestibule. Supraperiosteal tunnel from one premolar to other . Intervening submucosal tissue excised or repositioned repositioned superiorly.
Max. pocket inlay vestibuloplasty (obwegesser)
Procedure involves surgically creating pockets in the max,mattress and pyriform aperture region helps in the denture extension into the pockets Intraoral incision is taken just above the attached gingiva from one maxillary buttress to the other buttress Supraperiosteal dissection is performed to create two pockets on either side of pyriform aperture
Dissection is extended superiorly to the level of attachment of the levator anguli oris
Also continued in the midline upto the base of the pyriform aperture Impression is taken with the impression compound
Labial flanges of the dentures then covered with split thickness skin graft Bilateral circumzygomatic wires and pyriform margin wires used to stabilize the denture.
Mental nerve transposition
Patients with severe mandibular atrophic ridges - Complain of pain after wearing denture because of superior position of the mental neurovascular bundle - Repositioning of the mental nerve should be done.
A crestal incision is taken with buccal releasing incision in the region of premolars
Mucoperiosteal flap is reflected inferiorly to locate the nerve
Dissection below the foramen till the inferior border of the mandible should be done and the nerve is freed lightly and held with hook upward. Bony groove is cut below the mental foramen,only in the buccal cortex. Nerve is positioned inferiorly and secured in place with the gelfoam and flaps is sutured.
RIDGE AUGMENTATION PROCEDURES
When alveolar ridge resorption is so extreme - vestibuloplasty is not done.
Two options are available Augmentation of alveolar bone. Place the implants.
Procedures
Mandibular augmentation 1. Superior border augmentation Bone grafts
cartilage graft
alloplastic grafts
2.inferior border augmentation bone grafts
cartilage grafts
3.interpositional or sand witch bone grafts Bone grafts
Cartilage grafts
hydroxyapatite blocks
4. visor osteotomy 5.onlay grafting autogenous allogenous alloplastic
B. Maxillary augmentation. Onlay grafting
Onlay grafting of alloplastic material Interpositional or sandwitch grafts Sinus lift procedure
Augmentation in combination with orthognathic surgery mandibular osteotomy procedure
maxillary osteotomy procedure
Combination
Materials for augmentation of alveolar ridge autogenous grafts iliac crest rib graft allogenic bone freeze dried cadaver bone. Alloplastic material Hydroxyapatite
Mandibular augmentation Superior border grafting or augmentation
Use 15 cm rib graft Fixed to mandible with trans osseous wiring or circum mandibular wiring.
Disadvantage Donor site morbidity Continued resorption of grafted sites. Soft tissue dehiscence or limitation
Inferior border grafting It is indicated when the arch less than 5- 8 mm in height. Procedure Supraclavicular incision followed by subplatysmal incision till the inferior border of the mandible.
Freeze dried allogenic cadaver mandible is hollowed out and multiple perforations made into it and it is used as a tray.
It is then filled with autogenous cancellous graft particles fixed to the inferior border with 2-0 vicryl sutures by circummandibular fixation
Interpositional bone grafting ( sandwitch bone grafting)
Horizontal osteotomy is performed Splitting is done and bone graft is grafted into this gap
In mandible , autogenic or allogenic bone or hydroxyapatite grafts can be used. Delivery of appliance is delayed for 3-5 months.
Onlay grafting Used in case of inadequate width but adequate height for the maxilla or mandible
Oldest technique Onlay augmentation with hydroxyapatite is advocated by obwegessor via submucosal vestibuloplasty technique.
After creating a tunnel via a midline a putty is formed of hydroxyapatite crystals mixed with saline or blood and is injected via syringe into the submucosal tunnel. Solid or porous blocks of hydroxyl apatite is used. Split thickness ribgraft or iliac crest can be used.
Technique High vestibular incision is taken , mucoperiostial flap is reflected to expose the defect.
Small perforations made in this external cortex by using small round bur. Grafting material is placed or mounted over the external cortex.
Visor osteotomy
To increase the height of mandibular ridge for denture support. Consists of central splitting of the mandible in buccolingual dimension and the superior positioning of the lingual section of mandible wired in position Cancellous bone grafting material placed at the outer cortex over the superior labial junction for improving the contour.
Modified visor osteotomy
Consists of splitting of the mandible buccolingually by vertical osteotomy only in the posterior region and a horizontal osteotomy in the anterior region. Posterior lingual segments are then pushed superiorly on both sides.
Anterior fragment is also pushed superiorly and fixed with wires. Cortico-cancellous bone graft particles with hydroxyapatite granules placed in the gap between the superior , inferior and anterior segments.
Sinus lift procedure or sinus grafting
Sinus lining at the floor of the mouth is lifted up surgically and the bone graft is placed between the sinus lining and the inner aspect of the alveolar crest or floor of the maxillary sinus in the posterior maxilla.
Totum was the first surgeon who used this method.
Materials used are autogenous bone allogenic bone. tricalcium phosphate’ hydroxyapatite. calcium phosphate. ceramics calcium deficient carbonate apatite from bovine bone.
Technique Intraoral incision is taken on maxillary crest or slightly on the palatal aspect with vertical incision from canine to tuberosity area
Antrolateral wall of maxilla is exposed by reflecting the mucoperiosteal flap Bony windows made with trap door type osteotomy , lateral and posterior to the canine fossa
15 – 20 mm long inferior osteotomy cut placed 3mm above the sinus floor Anterior vertical cut parallel to the lateral nasal wall and perpendicular to the horizontal osteotomy. Posterior vertical cut is at the maxillary tuberosity. Vertical cuts are joined superiorly by placing the small bur holes placed at small intervals without completing the
Trap door type of bony window is lifted up superiorly to expose the schineiderian membrane. Gap between lifted sinus membrane and the floor is filled with graft material. One stage implant
Coticocancellous iliac crest bone block Otherwise 6-9 months before implant placement
Augmentation in combination with orthognathic surgery
1.anterior maxillary osteotomy. 2.total lefort osteotomy used along with interpositioning of grafts.
Limitation of augmentation technique 1.inadequate soft tissue coverage.
2.rejection of autografts. 3.dehiscence of overlying mucosa.
4.migration of graft material. 5.resorption of graft.
Review of the literature
Two studies (1981–1990 retrospective, and 1989–1993 prospective) were performed to determine the optimal methods in preprosthetic surgery.
[The optimal vestibuloplasty in preprosthetic surgery of the mandible. T. Fröschl, A. Kerscher. Journal of CranioMaxillofacial Surgery Volume 25, Issue 2, April 1997, Pages 85–90]
The first study deals with four different types of grafts (split thickness skin, mucosal, mesh mucosal, palatal) in combination with vestibuloplasties and lowering of the floor of the mouth.
Keratinized grafts (split-thickness skin and palatal) showed advantages. On the basis of a high rate of complications at the site of harvesting of palatal mucosa and the limited amount of palatal mucosa available for grafting, prefer a split-thickness skin graft.
A second prospective study to compare the Edlan- and Kazanjianplasty showed the disadvantages of both methods. The Edlan-plasty, in combination with implants, showed a small amount of bone resorption; the Kazanjian-plasty showed a significant loss of attached mucosa.
For cases with insufficient width of attached mucosa, recommend a vestibuloplasty secondarily, with keratinized grafts. If there is a deep palatal vault and the need for a large amount of graft material, a split-thickness skin graft should be harvested. In cases of limited need and flat palatal vault, the graft can be harvested from the palate.
The surgical carbon dioxide laser has the ability to vaporize soft tissues with little bleeding, pain, swelling, or wound contraction. evaluation.
[The carbon dioxide laser in soft tissue preprosthetic surgery. M. A. Pogrel, (J PROSTHET DENT 1989;61:203-8.)]
The laser was evaluated on 27 patients requiring soft tissue preprosthetic surgery, including frenectomies, tuberosity reduction, hyperplasia removal, and sulcus deepening.
Surgery was performed on an ambulatory basis with no bleeding or infection. Swelling was minimal and pain, as measured on a linear pain scale, was moderate. One third of the patients required no analgesics.
Wound contraction did occur but was less than is historically quoted for scalpel wounds. The carbon dioxide laser would appear to have advantages for soft tissue preprosthetic surgery that warrant further
Hillerup concluded in his article: Preprothetic surgery is still a relevant treatment option for elderly patients.
Well-defined prosthodontic needs of ridge improvement may be satisfied in a simple and cost-effective manner with the aid of preprosthetic surgery.
The combination of preprosthetic surgery and implants may solve problems that neither of the two can alone do. Interdisciplinary cooperation is a prerequisite for optimal service.
[Preprosthetic surgery in the elderly. Soren Hillerup. J PROSTHET DENT 1994, 72 : 551-8]
The objective of the study was to compare denture satisfaction and chewing ability of edentulous patients treated with dental implant-retained overdentures or with full dentures with or without previous preprosthetic surgery.
[E.M Boerrigter.Patient satisfaction and chewing ability with implant-retained mandibular overdentures: A comparison with new complete dentures with or without preprosthetic surgery . Journal of Oral and Maxillofacial Surgery Volume 53, Issue 10, October 1995, Pages 1167 1173]
Based on the baseline data from the “denture complaints” and “chewing ability” questionnaires, nine interpretable factors could be extracted. Two factors did not vary following treatment and were excluded from the outcome analysis.
At the 1-year evaluation five of seven factors showed significantly better scores for the two surgical groups than for the control group. The same was found for the overall denture satisfaction rate.
Overdentures retained by dental implants or complete dentures made after a vestibuloplasty and deepening of the floor of the mouth provide a more satisfactory solution for denture-related problems than complete dentures alone.
Conclusion
Preprosthetic surgery offers a sigificant contribution in patients with bone atrophy,soft tissue hypertrophy or localized soft and hard tissue problems or all of them .
Pre existing structures like frenal attachments, exostosis,tori are insignificant while teeth are present in the oral cavity.
But these non significant structures cause hindrances for denture stability and resultant reduced masticatory function after tooth loss.
Preprosthetic surgery plays an important role in providing a better anatomic environment and to create proper supporting structures for denture construction.
REFERENCES 1. Hopkins
R. Color atlas of preprosthetic surgery. Philadelphia, Lea and Febiger, 1987; 2. The Academy of Prosthodontics Foundation. The Glossary of Prosthodontics Terms, 8th ed, GPT-8. St. Louis: CV Mosby ; 2005. 3. Rahn AO, Heartwell CM. Textbook of complete dentures, 5th ed, Philadelphia, Lea and Febiger, 1993; 59-110. 4. Winkler S. Essentials of complete denture prosthodontics. 2nd ed. Delhi: AITBS Publishers; 2000. 142-182. 5. Sharry J J. Complete denture prosthodontics. 3rd ed. London: McGraw – Hill Book Company; 15-27.
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Zarb GA, Bolender CL. Prosthodontic treatment for edentulous patients: Complete dentures and implant-supported prostheses. 12th ed. St. Louis: CV Mosby; 2004; 34-50. Fonseca RJ, Davis W. Reconstructive prepeostrhetic oral and maxillofacial surgery, Philadephia, WB Saunders, 1985. Peterson LJ, Ellis E, Hupp JR, Tucker MR. Contemporary oral and maxillofacial surgery, 2nd ed., St, Louis, Mosby publication, 1993. Michael CG, Barsoum WM. Comparing ridge resorption with various surgical techniques on immediate dentures. J Prosthet Dent 1976; 35: 142-145.
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