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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