Restoration Of Endodontically Treated Tooth PDF

Faculty of Dentistry Fixed Prosthodontics Division Lecture: Restoration Of Endodontically Treated Tooth Dr.: Rasmia Salem Date : 18/12/2023  1. Retention of core material in non-retentive abutments. 2. Badly mutilated teeth with loss of more than 50%...

Faculty of Dentistry Fixed Prosthodontics Division Lecture: Restoration Of Endodontically Treated Tooth Dr.: Rasmia Salem Date : 18/12/2023  1. Retention of core material in non-retentive abutments. 2. Badly mutilated teeth with loss of more than 50% of tooth structure. 3. Extensive proximal caries with unsupported facial wall. When the tooth can not be restored by any other type of restoration as: a-Extensive bilateral proximal decay with pulp exposure. Indications of b-Fractured tooth with pulp exposure. post c-Extensive coronal destruction of endo. treated tooth 4. Retainers for short span bridge when the abutments are placement: endodontically treated teeth. 5. When the root(s) of endo. treated tooth; a-Is biologically sound (no resorption or fracture). b-Has sufficient length, thickness & strength. c-Has properly filled root canal with perfect apical & lateral seal. d-Has no periapical pathosis. e-Has healthy periodontal & alveolar support PRINCIPLES OF TOOTH PREPARATION for post and core system: 1) PRESERVATION OF TOOTH 2) RETENTION: STRUCTURE : 3) RESISTANCE: PRINCIPLES OF TOOTH PREPARATION Resistance form for post and core system: B) Rotational resistance : When sufficient coronal tooth structure remains. Post rotation is prevented by the vertical coronal wall Coronal dentin has been completely lost, a small groove placed in the canal wall at the cervical bulkiest side (lingual aspect ) can serve as antirotational element. Rotational resistance in an extensively damaged tooth can be obtained from preparation of a small groove in the root canal. This must be in the path of placement of the post and core restoration. PRINCIPLES OF TOOTH PREPARATION for post Resistance and core system: The ferrule effect: A ferrule is defined as a vertical band of tooth structure at the gingival aspect of a crown preparation. The ferrule should be: a minimum of 1.5 – 2 mm high, have parallel axial walls, completely encircle the tooth, end on sound tooth structure (NOT ON THE CORE) Not invade the attachment apparatus of the tooth. PRINCIPLES OF TOOTH PREPARATION for post Resistance and core system: The ferrule effect: If a ferrule cannot be obtained: surgical crown lengthening or forced eruption may be required. PRINCIPLES OF TOOTH PREPARATION for post Resistance and core system: The ferrule effect: Importance of ferrule: ✓Long term success ✓Load distribution ✓Improve stability and rotation resistance ✓Ferrule provides bracing action to protect the integrity of the root.  Resistance The ferrule effect:  Resistance The ferrule effect: core antirotentional element post 6 important features for a successful design 1. Adequate apical seal. 2. Minimal canal enlargement 3. Adequate post length, 4. Positive horizontal stop (to minimize wedging), 5. Vertical walls to prevent rotation and 6. Extension of the final restoration margin onto sound tooth structure Methodology : 1. Post selection 2. Removal of endodontic filling 3. Post space preparation 4. Preparation of coronal structure 5. Post fabrication 6. Temporization 7. Try in and cementation 8. Core fabrication Methodology: 1) POST SELECTION 1. Root length 9.Post design 2. Tooth anatomy 10. Post material 3. Post width 11. Material compatibility 4. Canal configuration 12. Bonding capability 5. Amount of coronal tooth 13. Core retention structure 14. Retrievability 6. Torquing force and Stresses 15. Esthetics 8. Development of hydrostatic 16. Crown material pressure The ideal physical properties of a post material include: (1) Maximum protection of the root. (2) Adequate retention within the root. (3) Biocompatible / noncorrosive (4) Maximum retention of the core and crown. (5) Maximum protection of the crown margin cement seal. (6) Pleasing esthetics (7) Radiopaque Methodology : 2) REMOVAL OF ROOT FILLING MATERIAL: Before removing gutta-percha, calculate the appropriate post length. As a guide, make the post length equal to the height of the anatomic crown (or two-thirds the length of the root), but leave 5 mm of apical gutta-percha. On short teeth: An absolute minimum of 3 mm of apical fill is needed. If this cannot be achieved while the post remains very short, the tooth’s prognosis is poor, and extraction may be the best treatment choice Methodology : 2) REMOVAL OF ROOT FILLING MATERIAL: Thermal removal by a heated instrument such as a lateral compactor. Methodology : 2) REMOVAL OF ROOT FILLING MATERIAL: Mechanical removal by anon cutting end bur such as a Gates-Glidden or Peeso reamer Methodology : 2) REMOVAL OF ROOT FILLING MATERIAL: Methodology : 3) Canal enlargement: Before the canal is enlarged, the type of post system that will be used for fabrication of the post and core restoration must be chosen. Prefabricated Posts: Many prefabricated posts are available in kits that include rotary instruments for post space preparation that correspond in size to the posts and core restoration must be chosen. Methodology : 4) Post cementation: Dual cure self adhesive resin cement: More recently, self-adhesive resin cements have been introduced, as an alternative to conventional resin-based luting cements. Methodology : 4) Post cementation: Classification of post and core system: post and core system: Methodology : 4) Custom made post construction : Methodology : 4) Custom made post construction : Indirect technique on the study cast Methodology : 4) Preparation of the Coronal Tooth Structure: Ignore any missing tooth structure (from previous After the post space has Remove all internal and restorative procedures, been prepared, the external undercuts that caries, fracture or coronal tooth structure is reduced for the endodontic access) and will prevent withdrawal prepare the remaining of the pattern. extracoronal restoration. tooth as though it were undamaged. Be sure that part of the Remove any unsupported remaining coronal tissue is Complete the preparation by tooth structure, but prepared perpendicular to the eliminating sharp angles and post because this will create a preserve as much of the positive stop to prevent over establishing a smooth finish crown as possible. line. seating and splitting of the tooth. core build up : IDEAL Requirements OF A CORE MATERIAL ❑High Compressive strength to resist intraoral forces. ❑Biocompatibility. ❑Ability to bond to tooth structure and post. ❑Coefficient of thermal expansion similar to dentin. ❑Dimensionally stable. ❑Compatible esthetics. core build up : Metal Custom- made core ceramics Core material Composite Plastic Amalgam core Glass ionomer RMGI core build up : Composite Resins Advantages: ▪ Excellent esthetics. ▪ Bonded. ▪ High tensile strength and the tooth can be prepared for a crown immediately after polymerization. ▪ It has fracture resistance comparable to amalgam and cast post and cores, with more favorable fracture pattern. Disadvantages: Composite shrinks during polymerization, Technique sensitive (isolation). Eugenol interfere with polymerization. core build up : Amalgam Core : Advantages: It has good physical and mechanical properties and works well in high stress area. In many cases, it requires the addition of pins or other methods to provide retention and resistance to rotation. Dimensionally stable Disadvantages: Objectionable esthetics Non adhesive Technique sensitive crown preparation must be delayed) core build up : Glass Ionomer Cements The glass ionomer materials, including resin- modified glass ionomer, lack adequate strength and fracture toughness as a build-up material and should not be used in teeth with extensive loss of tooth structure. It is also soluble and sensitive to moisture. When there is minimal loss of tooth structure and a post is not needed, GIC works well for block out such as after removal of an MOD restoration core build up : Cast Core The core is an integral extension of the post, and it does not depend upon the mechanical means of retention on the post. It prevents dislodgement of the core and the crown from the post. But sometimes valuable tooth structure must be removed to create path of withdrawal. Procedure is time consuming and expensive Recent advances : Endocrown: Endocrowns are a reliable alternative to post- retained restorations for molars and seem promising for mandibular premolars. The endocrown is referred to be a monolithic (one- piece) ceramic bonded construction with a supra- cervical butt junction that retains the most enamel possible to enhance adhesion. The pulpal chamber is invaded by the endocrown, but not the root canals. It is milled using CAD/CAM techniques or by molding ceramic materials under pressure Recent advances : Endocrown: Recent advances : Endocrown: Morphology Driven Preparation Technique: Overlays : Morphology Driven Preparation Technique: Morphology Driven Preparation Technique: Morphology Driven Preparation Technique: maxillary bicuspid, endodontically treated with a deep MOD New m DPT for indirect adhesive overlay cavity. There is a need for a complete cuspal coverage to restoration. preserve it from fracture Morphology Driven Preparation Technique: The principles of M DPT are intended to achieve these improvements: Minimize as much as possible the loss of healthy tooth tissue by reducing the areas of dentin exposure. Guide tissue reduction of the occlusal surface with depth cuts or, better still, with a silicone index for thick-ness control. Reduce the width of the margins prepared as a shoulder, where indicated. Improve the smooth insertion of the restoration during cementation. Improve the esthetics of the transition zone between the tooth and the restoration. Morphology Driven Preparation Technique: In chronological order, the preparation sequence is the preparation of the interproximal box, the anatomical reduction of the occlusal surface, and the definition of the margins on the axial walls. The margin definitions differ in maxillary and mandibular teeth. The design of the axial margins varies according to the residual sound tissue, the margin position, the inclination and slope morphology of the cusp, and the maximum tooth contour line (equator). The preparation is ultimately guided by the anatomical and structural morphology of the teeth. Morphology Driven Preparation Technique: Morphology Driven Preparation Technique: Morphology Driven Preparation Technique: References 1. Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett... (2012) Fundamentals of fixed prosthodontics, 4th Edition, Quintessence Publishing Co, Inc. 2. Rosenstiel SF Land MF Fujimoto J. (2016) Contemporary Fixed Prosthodontics. 5th edition. St. Louis Missouri: Elsevier. Rosenstiel SF Land MF Fujimoto J. Contemporary Fixed Prosthodontics - E-Book. (2022). United States: Elsevier Health Sciences.