Endo note 16 restoration of root filled
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Transcript of Endo note 16 restoration of root filled
Restoration Of Root FilledTooth
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Success rates of Endodontics is extremely high incontemporary practice (>95%)Even re- root canal treatment gives a very highsuccess rates in the present practice >60%Root treated teeth are in vulnerable state untilthey are permanently restored
14% reduction of strength and toughness due tochanges in collagen cross link and dehydrationFracture of remaining tooth tissue not due tobrittleness but due to loss of structural tissuewhich is holding tooth together under functionalload in posteriors.Rct reduce stiffness by 5% but tooth structureremoval by MOD stiffness by 60%
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Three major changes in rct toothLoss of tooth structureAltered physical charactoristicsAltered esthetic characteristics
In anteriors fracture is due to over extended accesscavity and not incorporating ferrule for coronalrestorationFailure rate of restorations is higher compared tovital teethMainly attributed to loss/ fracture remaining toothMay be contributed by poorly designed stressgenerating restorations eg MOD amalgams arewedges splitting teeth
Reinfection of the root canal from the mouth
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Over extended access cavity
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Wedging force on unprotected cusp
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Conventionally, believed that removal of pulp leads tochanges in physical properties – “brittle”No significant change in the physical propertiesfollowing endodonticsMajor effect of RCT is the loss of tooth structure.Root treated have previously being extensivelyrestored.Removing the root filling and preparing a post spacefurther weakens the toothStress generatedddduring endodontic and restorativeprocedures also contribute to failures by promotingcracks and fractures
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Aim at treatment with maximum preservationand protection of remaining tooth structureMinimizing stresses within the both tooth andrestoration. Avoid active restorations optionfor bonded onesConsider extraction and prosthesis when thetooth is unrestorable.
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Existing endodontic statusDelay the final restoration until peri- radicularhealing is evident radiographicallyDuring such period an adequate interimrestoration capable of preventing coronal leakage.Site of the tooth in mouth
Quality of root canal treatment
Type of final restoration
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The amount of remaining tooth structureAnatomic position of the toothThe occlusal forces on the toothThe restorative requirement of the toothAesthetic requirement of the tooth
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Preserve as much tooth substance as possibleIf post needed it should be long enough to beretentive and sufficient strong to resistdistortionAvoid twist drill for removal of GPAvoid active restoration which induce stressesProvide necessary coronal coverageattempt for the best possible fluid and bacterialtight seal
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Access cavity should not be over cutRoot canal should not be over flaredPreserve tooth substance by preparing properaccess cavity (labial access is acceptable)Posterior teeth should be reduced out ofocclusionRoot treated teeth are vulnerable to fracturebecause of access cavity and more toothsubstance loss due to caries
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GIC
Acrylic crown
Stainless steel crown
Over denture
Resin bonded bridge
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Conventional – weak crown
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Modified – poor aesthetic
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Decoronated root treatedanterior tooth vulnerable tofracture
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No protective ferrule isprovided by core or the crown
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Post and core provide noprotection, a ferrule is provideby crown
Beveling of residual tooth tissueallows both core and crown toprovide protective ferrule
A ferrule is a band of metal which totally encircles the tooth,extending 1-2mm into sound tooth tissue to guard againstlongitudinal fracture
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Post and core provide noprotection, a ferrule isprovide by crown
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Protective ferrule provideby a cast post anddiaphragm
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Minimizing further sacrifice of tooth material
Bleaching
Resin restorations are recommended aboveindirect restorations when ever possible
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Access cavity preparation in posterior teethmake them weekEven in the presence of marginal ridges toothstands a high risk of fractureComposite restoration increases the resistanceto fracture of root filled teeth compared to nonadhesive restorations.
Challenge in doing a good restoration in alarge posterior cavity, especially if approximalsurfaces are involved.Indirect tooth coloured restorations arerecommended in difficult cases.
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Tooth prepared with minimum access cavity andhaving size 1 or 2 lesions can be restored withsandwich technique
Remove all the GP anddCCement 2mm bellow thecervical margin with heat carrier and cariousdentine and discolored restorations
Seal GP with ZnPO4 liningPlace GIC (condensable) without trapping air
bubbles to pulp chamber and cavitiesAfter 1-7 days remove 2mm from GIC and
restored with LCC
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Tooth prepared with minimum access cavity andhaving size 1 or 2 lesions can be restored withamalgam or using sandwich technique
Place GIC (condensable) without trapping air bubblesto pulp chamber and cavities
After 1-7 days remove 2mm from GIC and restoredwith LCC
orRemove all the GP and Cement 2-3mm bellow the
cervical margin and use as retentive factorPlace amalgam with matrix band and holder
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Remove all the GP and Cement 2-3mm bellow thecervical margin and use as retentive factor
Cavity prepare to protect the physical fictional cuspIf esthetic and functional demands are fulfill adhesive
restorations can be donePlace amalgam with matrix band and holder
OrPrepare cavity for onlay or ¾ crown take impression
temporized the toothFinal restoration cemented with resin cement
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Cuspal protection – simple metal onlay
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Canal entrance use for core
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Ortho band strengthen the crown
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THREE QUARTERCROWN
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FULL METAL CROWN
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Post offer no reinforcementandmain function of the post is retain the coreDentine removal for insertion of postweakening the toothCreate an area of stress concentration at theterminus of the channelIf adequate retension can be obtained withnatural undercuts in pulp chamber and canalentrance post should not be used
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Custom cast metal post little tissue loss
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Remove more tissue weaken crown,stress on sharp edges and fracture
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Roof top preparation remove all the remaining coronal tissuecompromise protective ferrule
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Conservative preparation preserve tooth , lengthens the post,allow to development of protective ferrules
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Long post and parallel are more retentive thanshort post4-5mm GP should remain apicallyPlace the post as long as apicallyPreserve the tooth as much as coronally
remaining dentine should be prepared wraparound coverage to get ferrule effectApically bevel tapered posts are preparedTreaded post should be insert first to cut atread and then reinsert with cementCustomised post can be prepared withminimum dentine removal and stresses
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Parapost – parallel & serrated
Radex anker- parallel, self tapping or pre-tappedpost
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Dentatus screw – tapered self tapping post
Kurer anchor – parallel threaded post for which the root canal is pre-tapped
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Parallel post at the base
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Chamfered tip – reduce stress
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Post space preparation should be done on same daythat RC obturation is done becauseoperator is more familiar with RC & referral pointable to condense GP apicallycan be done under rubber dam
GP should be removed with Gate bur up to correctlength
Canal should be prepared with proper twist drillwhich is tally with the post up to correct length
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Cast post and core with diaphragm tocover and support a damaged incisor root
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METAL POST AND CORE WITH CHAMFER PREPARATIONSHORT BUCCUL POST AND SEPARATE POST INSERTEDTHROUGH CORE INTO THE PALATAL ROOT
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UNSATISFACTORYRCT
SATISFACTORY RCT WITH POORCORONAL SEAL
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Cutting through porcelain reduce strength ofthe crown, weaken the porcelain bond,predispose to fracture, vibration disturbcement lute and clamp damage cervicalporcelainMetal prevent X ray assessment and loss oforientation misdirected cuttingEach tooth before crowning should be assessedwell (appearance, percussion, biting pressure,caries, NCTSL,, restorations, vitality, X ray andprevious RCT)
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