restoration of ally treated teeth-4th year

8/4/2019 Restoration of ally Treated Teeth-4th Year

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Restoration ofRestoration of

Endodontically Treated TeethEndodontically Treated Teeth

Wael AlWael Al--Omari.Omari.BDS, MDentSci, PhDBDS, MDentSci, PhD



I ntroductionI ntroduction

An endodontically treated tooth can resume An endodontically treated tooth can resumefull functionfull function

And can serve as an abutment for Fixed or And can serve as an abutment for Fixed orRemovable partial dentureRemovable partial dentureThese teeth have lost most of their structureThese teeth have lost most of their structuredue to caries, RCT and previous restorationsdue to caries, RCT and previous restorations

Loss of structure increases likelihood of Loss of structure increases likelihood of fracturefractureSpecial techniques are thus required toSpecial techniques are thus required torestore endodontically treated teethrestore endodontically treated teeth



F actors influence theF actors influence the

choice of techniquechoice of techniqueType of toothType of tooth

The amount of remaining coronalThe amount of remaining coronaltooth structure: the most important tooth structure: the most important prognosisprognosis--determining factordetermining factor



Treatment PlanningTreatment PlanningEvaluate restorability of extensively carious toothEvaluate restorability of extensively carious toothExtensively carious tooth should be preserved if its loss mayExtensively carious tooth should be preserved if its loss may

jeopardize the occlusal function or the total treatment plan or if jeopardize the occlusal function or the total treatment plan or if dental implants are not an optiondental implants are not an optionEvaluate existing root canal treatment:Evaluate existing root canal treatment:11-- Apical seal: retreat or observe for success and failure Apical seal: retreat or observe for success and failure22-- Tenderness to percussion and palpationTenderness to percussion and palpation33-- Presence of exudates or fistulaPresence of exudates or fistulaMobilityMobilityPeriodontal assessment Periodontal assessment Restorative assessment Restorative assessment 11-- Amount of remaining tooth structure Amount of remaining tooth structure22-- Anatomical position of the tooth Anatomical position of the tooth33-- Functional load on the toothFunctional load on the tooth44-- Aesthetic requirements of the tooth Aesthetic requirements of the tooth



Treatment PlanningTreatment Planning

Anterior teeth: adequate coronal structure, restore Anterior teeth: adequate coronal structure, restorewith simple plastic fillingwith simple plastic fillingIf substantial structure is lost then indicated forIf substantial structure is lost then indicated forpost post--andand--corecorePosterior teeth: utilize pulp chamber or cementedPosterior teeth: utilize pulp chamber or cementedposts with coreposts with coreOneOne--piece technique is Contraindicated.piece technique is Contraindicated.

Two piece technique is superior:Two piece technique is superior:(1) Better marginal fit, (2) permit fabrication of a(1) Better marginal fit, (2) permit fabrication of areplacement crown, (3) different path of insertionreplacement crown, (3) different path of insertionof the crown.of the crown.



One-piece post crown

Two-piece post crown



C linical F ailureC linical F ailure

Different morphological and biomechanicalDifferent morphological and biomechanicalloading of anterior & posterior teeth dictateloading of anterior & posterior teeth dictatedifferent treatment strategies.different treatment strategies.Failure occur more readily under lateralFailure occur more readily under lateralloading.loading.Cantilevers cause more failure inCantilevers cause more failure inendodontically treated abutments restoredendodontically treated abutments restoredwith post and corewith post and coreCast vs. Prefabricated: comparative successCast vs. Prefabricated: comparative successrate. However, studies were not conclusive.rate. However, studies were not conclusive.



C onsiderations forC onsiderations for

Anterior teeth Anterior teethMetal Post is only recommended if fullMetal Post is only recommended if fullcoverage restoration is required.coverage restoration is required.Disadvantages of Posts:Disadvantages of Posts:11-- Requires additional removal of toothRequires additional removal of tooth

structure, thus weaken the toothstructure, thus weaken the tooth22-- limit or complicate endodonticlimit or complicate endodontic

retreatment.retreatment.

33-- Complicate future retreatment if Complicate future retreatment if coronal destruction occurs.coronal destruction occurs.Complete coverage is necessary if Complete coverage is necessary if tooth will be used as an abutment fortooth will be used as an abutment forFPD or RPDFPD or RPD



C onsiderations forC onsiderations for

Posterior teethPosterior teethPosterior teeth due to greaterPosterior teeth due to greaterloadings and having cusps areloadings and having cusps aremore susceptible to fracture.more susceptible to fracture.(Mandibular premolars & 1(Mandibular premolars & 1 st st

molars are least susceptible tomolars are least susceptible tofracture)fracture)Endodontically treated posteriorEndodontically treated posteriorteeth should receive cuspalteeth should receive cuspalcoveragecoverageComplete coverage is indicatedComplete coverage is indicatedon teeth with high risk of fractureon teeth with high risk of fracture(example: maxillary premolars).(example: maxillary premolars).



Principles of toothPrinciples of tooth

PreparationPreparationConservation of tooth structure:Conservation of tooth structure:

Strength of the tooth structure comes from itsStrength of the tooth structure comes from itsperiphery not from its interior.periphery not from its interior.The fracture incidence increases as the post diameterThe fracture incidence increases as the post diameterincreasesincreasesOverOver--preparation of post space may lead to root preparation of post space may lead to root

splitting during cementation or loadingsplitting during cementation or loading




PreparationPreparationConservation of tooth structure (coronal preparation):Conservation of tooth structure (coronal preparation):E very effort should be done to preserve asE very effort should be done to preserve as

much as possible coronal tooth structure.much as possible coronal tooth structure.Provide a ferrule: extension of axial wall of theProvide a ferrule: extension of axial wall of thecrown apical to the missing tooth structure tocrown apical to the missing tooth structure toenhance resistance to fracture.enhance resistance to fracture.



ethods to create ferrule inMethods to create ferrule in

extensively destryed toothextensively destryed toothSurgical crown lengtheningSurgical crown lengthening

-- Reduce root length and increase crown lengthReduce root length and increase crown length(crown: root ration unfavorable)(crown: root ration unfavorable)

Orthodontic extrusionOrthodontic extrusion-- Reduce root length and unchanged crown length (crown:Reduce root length and unchanged crown length (crown:root ratio is favorableroot ratio is favorable ))

Ortho. extrusion S urgical crown lengthening




PreparationPreparation1- Adequate apical seal (4 mm)

2- Minimal canal enlargement

3- Adequate post length (= crownlength or 2/3 root length)

4- Positive horizontal stop (to prevent

overseating and minimize wedging)

5- Vertical wall to prevent rotation.

6- Finished on sound tooth structure

(Ferrule)



Retention formRetention formPreparation Geometry:Preparation Geometry:Parallel post are more retentive than tapered, and threadedParallel post are more retentive than tapered, and threadedare the most retentive.are the most retentive.Threaded posts are not recommended due to residual stresses,Threaded posts are not recommended due to residual stresses,however stresses are reduced if posts are backed offhowever stresses are reduced if posts are backed offIn elliptical canals, parallelIn elliptical canals, parallel- -sided post preparation would causesided post preparation would causeconsiderable enlargement and subsequently weaken the root considerable enlargement and subsequently weaken the root

Post Length:Post Length:

Post should be as long as possible without jeopardizing thePost should be as long as possible without jeopardizing theapical seal or strength or integrity of root canal structure.apical seal or strength or integrity of root canal structure. An apical seal of 5 mm is advocated. An apical seal of 5 mm is advocated.In short roots, an apical seal of 3 mm is considered acceptableIn short roots, an apical seal of 3 mm is considered acceptable



Retention formRetention form

Post Diameter:Post Diameter:The post should not be more than 1/3 the diameterThe post should not be more than 1/3 the diameterof the root with the walls at least of 1 mmof the root with the walls at least of 1 mmthickness.thickness.Post S urface Texture:Post S urface Texture:Serration, roughening and controlled groovingSerration, roughening and controlled groovingincrease the retention of tapered postsincrease the retention of tapered posts

Luting Agent:Luting Agent:Resin cements are indicated for short or dislodgedResin cements are indicated for short or dislodgedposts.posts.



A: smooth, tapered; B: Tapered serrated; C: Threadedtapered; D: smooth, parallel-sided; E : serrated, parallel-sided;F: Threaded, parallel-sided



Retention form: PosteriorRetention form: Posterior

teethteethLong posts are not recommended due to curvedLong posts are not recommended due to curvedelliptical rootselliptical roots

Amalgam could be condensed around short Amalgam could be condensed around short cemented posts or directly into short prepared post cemented posts or directly into short prepared post spaces.spaces.If more than 3If more than 3- -4 mm of coronal structure exists,4 mm of coronal structure exists,posts are not neededposts are not neededIn case of one or more missing cusps, post cementedIn case of one or more missing cusps, post cemented

in distal root of mandibular and palatal root of in distal root of mandibular and palatal root of maxillary molars could be utilizedmaxillary molars could be utilizedIf 3 or more cusps missing, a cast post and coreIf 3 or more cusps missing, a cast post and corecould be used.could be used.



Resistance formResistance form

S tress distribution:S tress distribution:E xcessive internal preparation weakens the root.E xcessive internal preparation weakens the root.

Post design should distribute stresses as evenly asPost design should distribute stresses as evenly aspossiblepossibleGuidelines to reduce stresses:Guidelines to reduce stresses:Conserve dentine at the shoulder & apexConserve dentine at the shoulder & apexIncrease post length as possible.Increase post length as possible.

Avoid sharp angles Avoid sharp anglesProvide cement vents for smooth parallelProvide cement vents for smooth parallel- -sided postssided posts

Avoid threaded post or back it off a half Avoid threaded post or back it off a half- -turnturn



Resistance formResistance form

Rotational Resistance:Rotational Resistance:Sufficient tooth structure providesSufficient tooth structure providesresistance against rotationalresistance against rotationalforcesforcesIf coronal tooth structure is not If coronal tooth structure is not available, an antiavailable, an anti- -rotationalrotationalgroove is prepared in the bulkiest groove is prepared in the bulkiest

areas (usually lingual), or byareas (usually lingual), or byusing pins on the root faceusing pins on the root face



ProceduresProcedures

1.1. Removal of root canal filling toRemoval of root canal filling toappropriate depth.appropriate depth.

2.2. E nlargement of the canal.E nlargement of the canal.3.3. Preparation of the coronal toothPreparation of the coronal tooth

structure.structure.



Removal of root canalRemoval of root canal

filling materialfilling materialPost can t be placed if canal is obturated with silver point,Post can t be placed if canal is obturated with silver point,Canal should be obturated with GPCanal should be obturated with GPMethods of GP removal:Methods of GP removal:

11-- Thermal: warm endodontic pluggerThermal: warm endodontic plugger22-- Mechanical: rotary instrument Mechanical: rotary instrument

Immediate Vs. Delayed removal of GP:Immediate Vs. Delayed removal of GP: Advantages of removal of GP immediately after obturation: Advantages of removal of GP immediately after obturation:

11-- operator has greater familiarity with the root canal morphologyand its working length

22-- there is less risk of coronal tooth tissue fracturing, so losing thereference point from where the working length was determined

33-- Apical seal is less disturbed Apical seal is less disturbed44-- GP preserves its thermoplasticityGP preserves its thermoplasticity



Removal of root canalRemoval of root canal

filling materialfilling materialCalculate the appropriate post length.Calculate the appropriate post length. Avoid apical 5 mm Avoid apical 5 mm Use heated pluggerU se heated pluggerThen use a safeThen use a safe- -tip rotarytip rotaryinstruments such as Peeso reamersinstruments such as Peeso reamersor Gates Glidden drillsor Gates Glidden drillsThe rotary instrument selectedThe rotary instrument selected

should be slightly narrower than theshould be slightly narrower than thecanal.canal. Use twist drills only to enlarge theU se twist drills only to enlarge thecanal not to remove GP.canal not to remove GP.



A: safe-tip Peeso reamer; B: end-cutting burand C: end-cutting drill



Enlargement of the canalEnlargement of the canal

Enlargement is dependent on the selectedEnlargement is dependent on the selectedpost design & diameter.post design & diameter.

Operator should be familiar with different Operator should be familiar with different techniques to choose the most suitable fortechniques to choose the most suitable foreach case.each case.Parallel sided prefabricated posts areParallel sided prefabricated posts are

recommended in small circular canals,recommended in small circular canals,whereas custom made posts arewhereas custom made posts arerecommended for nonrecommended for non- -circular orcircular orexcessively flared canals.excessively flared canals.



The recommended dowel (post) diameters



Enlargement of the canalEnlargement of the canal



Preparation of thePreparation of the

coronal tooth structurecoronal tooth structurePrepare the tooth as if it is intact Prepare the tooth as if it is intact

Remove unsupported coronal tooth structure andRemove unsupported coronal tooth structure and

eliminate internal and external undercutseliminate internal and external undercutsMake sure that part of the prepared tooth isMake sure that part of the prepared tooth isperpendicular to the post to prevent overseating orperpendicular to the post to prevent overseating orsplittingsplitting

Prepare part parallel to the post as antiPrepare part parallel to the post as anti- -rotational featurerotational feature Adequate axial reduction with eliminating all sharp Adequate axial reduction with eliminating all sharpangles and establishing a smooth finish line.angles and establishing a smooth finish line.Preserve as much coronal structure as possible (minimumPreserve as much coronal structure as possible (minimum2 mm height and 1 mm wide ferrule)2 mm height and 1 mm wide ferrule)



Coronal reparation : removal of unsupportedstructure, with adequate axial reduction anddefinite finish line



Post fabricationPost fabrication

Prefabricated Posts:Prefabricated Posts:Threaded parallel sided posts: PtThreaded parallel sided posts: Pt- -Au Au--Pd, NiPd, Ni- -C r, C oC r, C o--C r, SSC r, SS

tapered posts: Autapered posts: Au- -Pt, NiPt, Ni- -C r, titanium alloysC r, titanium alloysC arbon fibers: bundles of stretched aligned carbon fibers embedded inC arbon fibers: bundles of stretched aligned carbon fibers embedded in

epoxy matrix. Ease of removal thus for teeth with questionable log termepoxy matrix. Ease of removal thus for teeth with questionable log termprognosis.prognosis.High strength ceramic posts: zirconia postsHigh strength ceramic posts: zirconia postsC eramic composite postsC eramic composite postsWoven fiber postsWoven fiber posts



Prefabricated PostsPrefabricated Posts

Parapost parallel,serrated

Radix Anker parallel,self-tapping or pre-tappedpost

Dentatus screw tapered,self-tapping post



C ustomC ustom- -made Postsmade Posts

Direct Technique:Direct Technique:direct pattern fabricateddirect pattern fabricated

in the patient s mouthin the patient s mouthusing eitherusing eitherautopolymerizing or light autopolymerizing or light- -polymerizing resin.polymerizing resin.Recommended for singleRecommended for singlecanalscanals

Direct pattern using a thermoplastic post



Direct technique using ParapostDirect technique using Parapost

system and GC

acrylic patternsystem and GC

acrylic pattern



Post fabricationPost fabrication

C ustomC ustom- -made Post:made Post:Indirect Technique: utilizing an impression forIndirect Technique: utilizing an impression forthe post space and indirect pattern fabricatedthe post space and indirect pattern fabricatedin the lab.in the lab.

More appropriate for multiple canalsMore appropriate for multiple canals



I ndirect methodI ndirect method

GP removal withGG bur

Enlargementwith parapostdrills

Impression posts picked up insilicone impression



I ndirect method for posterior toothI ndirect method for posterior tooth



C ore fabricationC ore fabrication

Plastic filling materials:Plastic filling materials: Amalgam, GI or resin. Amalgam, GI or resin. Advantages: Advantages:

11-- Conserve tooth structure as no needConserve tooth structure as no needfor removal of undercutsfor removal of undercuts

22-- Treatment is one visit lessTreatment is one visit less33-- Satisfactory strengthSatisfactory strength



Provisional RestorationProvisional Restoration



C ementationC ementation

Cement should beplaced in the post space with a lentulospiral

The post is coatedwith cement andgently seatedcompletely

A groove should beplaced along the sideof the post to allowexcess cement toescape



Removal of existing postsRemoval of existing posts

Removal is necessary in case of retreatment Removal is necessary in case of retreatment It is a risky procedure that might lead to root It is a risky procedure that might lead to root

fracture.fracture.U ltrasonic scaler is recommended to break theU ltrasonic scaler is recommended to break thecement interfacecement interfaceU

se of post puller (Masserann Technique).U

se of post puller (Masserann Technique).




Masserann

Kit for postremoval

restoration of ally treated teeth-4th year

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