MANAGEMENT OF MUTILATED TEETH DEFINITION Mutilated tooth is that tooth which is grossly weakened and badly broken down where the amount of remaining tooth structure is less than the amount of tooth loss.
Causes of Mutilation A) Long standing caries B) Traumatic fracture
C) Recurrent caries
Causes of Mutilation A) Long standing caries: Factors that increase Dental Caries Progression:
Patients with enamel hypoplasia,, hypocalcification. hypoplasia hypocalcification. Patients with bad oral habits (eating sweets,sticky food,). Patients with bad oral hygiene.
B)
Traumatic fracture Maybe due to Traffi raffic c acciden accidentt Bicycle falls Blows to the face Chewing hard objects c) Recurrent caries It is considered the cause of mutilation to already placed restoration
Characteristics of mutilated teeth 1.
Partial or complete loss of cusps. c usps. 2. Loss of marginal ridges or crossing ridges. 3. Loss of axial angles. 4. Negative crown / root ratio, which is normally 1:3.
Characteristics of mutilated teeth 5.
Partial or complete loss of crown/root junction. 6. Multiple cracks with an unlimited 6. extent or appearance of signs and symptoms of cracked tooth syndrome.
SEQUALAE OF MUTILATION
1.
Weakening of remaining tooth substance decrease retention and resistance 2. May endanger normal pulp physiology , periodontal health and restoration of esthetics
SEQUALAE OF MUTILATION 3. Drifting or over eruption of teeth complicating restoration and compromising success
Examination and clinical assessment of tooth 1)
Caries incidence (low, high )
patient with low caries incidence (adhesive res.) Composite resin in stress bearing areas Glass ionomer in less stresses
Patients
with high caries incidence Amalgam or full coverage 2)Oral hygiene. Bad oral hygiene (amalgam) 3) Periodontal status. 4)The amount of remaining tooth structure
5)
Amount of forces to which the tooth is subjected. 6) Bad habits. 7) Mobility. 8) Cracks.
Restorative -.
treatment
Anterior teeth : - Resin composite. (complex fracture and horizontal) - Porcelain laminate. (multiple fracture) - Ceramic or porcelain fused to metal restorations.(loss of two incisal angle together, multiple defect )
Restorative
treatment
II. Posterior teeth: Amalgam restoration Resin composite Inlays or Onlays Full coverage restoration
CAVITY PREPARATION FOR DIRECT RESTORATIONS GENERAL RULES: 1)
2)
Remove all carious dentin and all undermined enamel. The outline of all the cavity is extended into smooth cleansable enamel
AMALGAM : Facial and lingual walls of the cavity should converge occlusally with a C.S.A. of 90 degrees . of Additional resistance and retention mean Capping cusps, Retention locks, Slots, Dentin chambers and Pins.
CAPPING CUSPS: - Needed when caries is extensive and when the lingual or facial extension is two third from a primary groove toward the cusp tip. - Functional cusps are reduced by 2mm minimum - Non functional cusps are reduced by 1.5mm
- Functional
cusps are reduced by 2mm minimum - Non functional cusps are reduced by 1.5mm
- Roundation of any sharp external corners is a must to reduce stress concentration in the amalgam. - Disadvantage: Reduction of the cusp significantly reduce the retention form by decreasing the length of the longitudinal walls.
RETENTION
LOCKS:
- w wherever herever possible, retention locks in dentin of the axial walls are are made by using fissure bur.
SLOTS: - Slots can be prepared along the gingival floor using an inverted cone bur. - Slots are placed 0.5 mm pulpal of the DEJ. - Slots are at least 0. 5 mm in depth and 1 or more mm in length.
- ADVANTAGES: 1. Slot Slot--retained -retained amalgam is more retentive than pinpin-retained -retained amalgam. 2. Slots are less likely to perforate the tooth. - DISADVANTAGE: More tooth structure is removed preparing slots compared with pins.
DENTIN
CH C HAMBER:
- Called Amalgapin technique. - Dentin chambers are prepared in the floor of the cavity with the bur parallel to the external surface of the tooth. - Depth is 2mm. - The junction between the pulpal floor and the walls of the chamber is beveled with round bur.
- DISADVANTAGES: 1. The potential of tooth perforation is greater than with slots. 2. Less retention than Slots and Pins.
Definition of pin-retained restoration It may be defined as any restoration requiring the placement of one or more pins in the dentin to provide adequate resistance and retention forms.
Advantage 1-conservation
of tooth structure 2- resistance and retention means 3-economics
Disadvantage 1-
dentinal microfracture microfracturess 2- microleakage 3- perforation
PINS:
-
Types of pins: 1.Cemented pins. 2. Self threading pins. 3.Friction locked pins.
1.
Cemented pins:
--They They are serrated -They are cemented by dental luting -They cement using lentulo spiral. -Diameter of pinhole preparation is -Diameter 0.0025 to 0.05mm larger than that of pin. -Pinholes are prepared at a depth of 3-Pinholes 3 -4 -4 mm.
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-
-
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ADVANTAGES: 1.Require minimal access for insertion. 2.Can 2. Can be measured, cut. bent., trial fitted before cementation. 3.Available 3. Available in 3 diameters. 4.No 4. No internal stresses upon placement. 5.Can be used in non vital tooth and vital tooth.
DISADVANTAGES: 1. Weak retention. 2. ZPC is irritant. 3. Retention of the pins in dentin is proportional to the strength of Cement Used and the length of pin into holes.
Self threading pins(TMS) 2. -
Available in three types: 1.The regular type (3 lengths ) Diameter 0.031, Pinhole 0.027 2.The Minim type (2 lengths) Diameter 0.024, Pinhole 0.021 3.The Minikin type Diameter 0.019, Pinhole 0.017 ( anterior restoration )
--ADVANTAGES: ADVANTAGES: 1.Strongest retention. 2.No cementation complications. 3.No pulp irritation. -DISADVANTAGES: -DISADVANTAGES: 1.Internal stresses. 2.Restricted to available access cavity. 3.Not used in non vital teeth.(Rely on dentin viscoelasticity.) 4.High cost.
3.Friction
locked pins:
--They They are smooth pins with continuous spiral groove. -The pin diameter is 0.001 larger than -The the twist drill. -The pinhole dept is 2-The 2 -3mm. -3mm.
-ADVANTAGES: 1.Strong retention. 2.No cement complications. 3.Quiqest & easiest method. 4.Provided in a variety of precut lengths. -DISADVANTAGES: 1.Internal stresses. 2.Its use is restricted to available access for pin insertion cavity. 3.Not used in non vital teeth.(Rely on dentin viscoelasticity.)
Factors affecting pin retention in dentin & amalgam 1.
2. 3. 4.
Type of pin. 2. Surface characteristics. 3. Orientation, Number and Diameter. 4. Extention in dentin and amalgam.
Factors affecting pin placement: 1.
2. 3. 4. 5.
6. 7. 8. 9. 10. 11.
Pin size: Factors affecting selection of size: a. amount of dentin available. b. amount of retention desired. 2.Pin number: Factors deciding the number: a. amount of dentin available. b. amount of retention desired c. amount of missing tooth structure. d. size of the pin. ONE PIN PER MISSING AXIAL ANGLE SHOULD BE USED
Consideration when placing more than one pin: 1.
2. 3. 4.
They should be placed at different levels. 2. Interpin distance; 3mm for the Minikin type 5mm for the Minim type.
Possible problems when using pins 1.
2. 3. 4.
Failure of restoration. 2. Broken drills or pins. 3. Loose pins. 4. Penetration into the pulp & perforation of the external tooth surface.
PINS:
- Indicated in anterior teeth but not used any more due to the development in the adhesive dentistry. - Teeth with little or no enamel to etch that are ideally restored with tooth colored crowns can be restored with pins only for economics and time restraints
Cast inlay/ onlays : Indications: 1.It
is the simplest of the cast restoration which is used to restore occlusal, gingival and proximal lesions. 2. Restoration of teeth which need cusp coverage. 3. Proximo - occlusal inlays is indicated for premolars and molars. 4.Class 4. Class I inlays can be used to restore a moderately sized occlusal lesion. 5.Class
III inlay is used to restore the distal surface of canine.
6.Class 6. Class V inlays is used to restore severe abrasion or erosion.
Contraindications Contraindicat ions of cast Inlays : Patients with accumulation of plaque or recent history of caries here the full coverage crown is the treatment tr eatment of choice.
:Cast onlays:Indications: 1-MOD
restoration with wide isthmuses. 2- The use of inlay in mesio 2mesio occluso occluso occluso--distal -distal lesions in premolars is questionable occlusal force on an inlay produces stresses along the sides of the restoration and at its base as the inlay pushes against the tooth structure surrounding it which could fracture the tooth so an inlay must be modified to distribute the load evenly over a wide surface covering the occlusal surface with metal has minimized the damaging effect of stresses in an interinter -coronal -coronal restoration. Restorative A) B)
C)
materials used for cast restorations:
Gold alloys. Base metal alloys. Sometimes for esthetic demands composite inlays may be used
Full coverage restorations: Full cast restoration rebuilding the prepared abuement teeth its either.
A) Full metal crown: Full metallic restoration rebuilding the prepared abutment teeth.
B) veneered crown: Full cast metal crown having the labial or buccal surface covered with acrylic or porcelain facing.
Indications of full coverage restoration: 1.
Badly broken down teeth when no other type of restoration can be used.
2.
Mutilated teeth with short OcclusoOccluso-gingival -gingival height. Mutilated teeth which need splinting for periodontal disease. Rotated , tilted and malposed teeth.
3. 4.
Reinforcement
of endodontically treated teeth
the pulpless teeth require different treatment from the tooth that still retains vitality. l. The cast post and core : 1.
Single rooted teeth
2.
Multi rooted teeth:
A) Straight rooted B) Divergent rooted teeth ll. Prefabricated posts: A) With amalgam core. B) Prefabricated Prefabricate d posts with composite core.
C. RESIN COMPOSITE:
1.
All en All enam enamel amel el margins marg ma rgin inss have have to be beveled to increase retention. 2. Additional resistance and retention means: Counter bevel, Reverse bevel, Secondary flares, Skirts and Pins.
COUNTER
BEVEL:
- Prepared on nonnon-functional -functional cusps. - The cusp is reduced 0.7 5mm. - A stone is placed with 30 degrees angle on the outer surface and the counter bevel is placed.
- Contraindicated in facial cusps of upper premolars and first molars for esthetics. So replaced by only blunting and smoothing of the enamel margins.
REVERSE -
BEVEL
Prepared on functional cusps. - Cusps are reduced by 1.5mm then reverse bevel is placed with chamfered margin on the external tooth surface.
SECONDARY
FLARES:
- Made on the proximoproximo-facial -facial and proximo--lingual proximo -lingual walls. - Approach from the lingual embrasure moving the stone proximo--facially proximo -facially to place the secondary lingual flare. - The same is done facially with opposite direction to place the secondary facial flare.
SKIRTS
PREPARATION:
- These are thin extentions of the facial or lingual proximal margins that extend from the secondary flare to end just beyond the line angle of the tooth. - Prepared entirely in enamel and may involve very little dentin ATRAUMATIC.
- Nev N Never ever er placed place pla ced d on on the the mesiomesi me sio o-facial -facial wall of the upper premolars and first molars for esthetics, so only secondary flares are done. - It all a allows llow owss bonded bonded bonde d composite compos com posit ite e to brace the toothincrease resistance to fracture.
PINS:
- Indicated in anterior teeth but not used anymore due to the development in the adhesive dentistry. - Teeth with little or no enamel to etch that are ideally restored with tooth colored crowns can be restored with pins only for economics and time restraints
