Restoration of the Endodontically Treated Tooth

Restoration of endodontically treated teethPrepared by : azheen mohamad

ReferenceCohen's pathway of pulp 10 th edition 2010,chapter 22 ,pp777.www.slide share.com

Restoration of the Endodontically Treated ToothEndodontic treatment is largely performed on teeth significantly affected by caries, multiple repeat restorations and/or fracture.

Already structurally weakened, such teeth are often further weakened by the endodontic procedures designed to provide optimal access .

Restorations of endodontically treated teeth are designed to:-(1) protect the remaining tooth from fracture. (2) prevent reinfection of the root canal system. (3) replace the missing tooth structure.

What are the objectives of Final restoration?1.Maintained coronal and apical seal of the root canal treatment .

2.Protect and preserve the remaining tooth structure.

3.Provided a supportive and retention ,foundation for the placement of definitive restoration.

4.Restore the function and esthetics.

What are the factors to be considered while planning the final restoration?Amount of remaining sound tooth structure.Occlusal function.Opposing dentition.Position of the tooth in the arch.Length, width and curvature of the roots.

Endodontically treated teeth are weakened due to:- caries and/or previous restorations. fracture or trauma. endodontic access and instrumentation. decreased moisture.

Cusp Fracture Of Endodontically Treated Teeth:_ endodontically treated teeth with intra-coronal restorations are at higher risk and the occurrence of unrestorable sub-gingival cusp fractures is more common.

there was a positive correlation between endodontically treated teeth and subgingival fracture location.

Esthetic Changes in Nonvital and Endodontically Treated Teeth:Color change and darkening of nonvital teeth is a common clinical observation.

Endodontic restoration of teeth in the esthetic zone require careful control of procedures and materials to retain a translucent, natural appearance.

Avoid the use of potentially staining endodontic cements and to clean all material residues in the pulpal chamber and access cavity.

Direct Composite Restorations:Anterior teeth:- Anterior teeth with minimal loss of tooth structure can be restored conservatively with a bonded restoration in the access opening. A post is of little or no benefit in a structurally sound anterior tooth ,Increases the chances of a failure.

Posterior teeth:Endodontically treated posterior teeth are subject to greater loading than anterior teeth, because of their position closer to the insertion of the masticatory muscles. clinical success rates of endodontically treated premolars restored with fiber posts and direct composite restorations or full coverage with metal-ceramic crowns were highly successful without any failures, even after 3 years of service .

Components Of Final Restoration:

I.PostsII.CoresIII.Crowns

POSTSCharacteristics of an ideal post:Minimum preparation.Resistance to fatigue. Non corrosive. Retentive (post & Head).Easy to adjust and fit.Radiopaque. Adequate materialEasy Removal

Indications of post:-The remaining coronal tooth structure is inadequate for the retention of a restoration.

When there is sufficient root length to accommodate the post while maintaining an adequate apical seal.

Post selection Factors to be considered :Post lengthPost diameterPost design

Post length

Post diameter

The diameter of the post is dictated bythe root canal anatomy. A minimal dentin thickness of 1 mm around the post should be provided

The post should be wide enough so that it does not deform under loading.

A post should not be so wide that the root is unnecessarily weakened, since this increases the risk of root fracture.

Post design:Posts can be serrated, smooth, roughened or threaded. Parallel, serrated posts are cemented into the canal passively.

They are retentive and produce less stress in the root dentine than threaded systems.

Ferrule EffectThe ferrule is the circumferential ring of sound tooth structure that is enveloped by the cervical portion of the crown restoration. A minimum sound dentine height of 1.5-2 mm is required between the core and crown margins.

Importance of ferruleThe ferrule provides bracing or casing action to protect the integrity of the root.

CORES:-Core of the post and core restoration replaces carious, fractured or missing tooth structure , It also retains the final crown.

Indications:

Core restorations are indicated if any of the following clinical conditions exist:-

The replacement of missing coronal tooth structure is necessary.

When the enhanced retention and resistance to displacement of the final restoration is necessary.

Materials used for core build up:

DIRECT PLACEMENT:Composite resinAmalgamGlass ionomer resin

INDIRECT PLACEMENT:Casting

Composite resin core

Amalgam core

Glass Ionomer resin core

So which is the best material for core buildup???The modulus of elasticity of amalgam is significantly higher than all other material tested and is closer to that of dentin.

Prepared core build-ups in a hybrid composite material provided the highest fracture resistance.

study showed that the tensile and flexural strengths of composite are significantly higher than that of amalgam and glass ionomer.

Crowns:Indications:Better esthetics.Situations in which the structural integrity of natural crown is compromised.

Contraindications:Anterior teeth have only have conservative access opening.

Advantages

Durable.Good esthetics.Restoring dental function.Good Form.Protection of tooth.

DisadvantagesLoss of tooth structureExpensive

Types:Metal-Ceramic Crowns.Porcelain Jacket Crown.Full Cast Metal Crowns.Partial Cast Metal Crowns.Temporary Crowns.