TOOTH PREPARATION: FULL VENEER CAST METAL CROWN

Principles and technique of tooth preparation for a molar to receive a full veneer cast metal crown

1. TOOTH PREPARATION IN FPD DR. AAMIR GODIL DEPARTMENT OF PROSTHODONTICS M.A.R.D.C.

2. QUICK RECAP TOOTH PREPARATION FOR FPD BIO- MECHANICAL PRINCIPLES OF TOOTH PREPARATION MARGIN GEOMETRIES MARGIN INDICATIONS

3. PRINCIPLES OF TOOTH PREPARATION The principles of tooth preparation may be divided into three broad categories: Biologic considerations: which affect the health of the oral tissues 2. Mechanical considerations: which affect the integrity and durability of the restoration 3. Esthetic considerations: which affect the appearance of the patient Contemporary fixed prosthodontics. Stephen Rosenstiel, Martin Land, Junhei Fujimoto- 5 th edition (2015)

4. MARGIN GEOMETRY Chamfer Shoulder Sloped Shoulder Knife Edge Feather Edge Radial Shoulder Shoulder with Bevel

5. MARGIN GEOMETRY

6. ALL METAL CROWN FULL VENEER CROWN FOR MOLAR

7. PREPARATION DESIGN

8. BIOMECHANICAL CONSIDERATIONS BIOLOGICAL CONSIDERATIONS 1. Prevention of damage Pulp Periodontium 2. Conservative preparation Cast metal restoration Minimal taper Avoidance of over contour 3. Margin placement and adaptation Supragingival Well flushed 4. Harmonious occlusion and prevention of tooth fracture

9. BIOMECHANICAL CONSIDERATIONS MECHANICAL CONSIDERATIONS 1. Retention form Taper: ~6 degrees Prevention of undercuts Optimal surface area of preparation Retentive luting agent 2. Resistance form Adequate taper and height: width ratio Pinholes/ grooves/ boxes Choice of luting agent 3. Prevention of deformation Adequate tooth preparation Alloy selection: Noble/ base metal Margin placement and geometry

10. BIOMECHANICAL CONSIDERATIONS ESTHETIC CONSIDERATIONS 1. Metal vs PFM/ all ceramic × Compromised esthetics 2. Acrylic facing/ porcelain facing × Less conservative 3. Partial coverage × Not applicable

11. ARMAMENTARIUM Armamentarium for the complete cast crown preparation

12. ARMAMENTARIUM Torpedo bur

13. OVERVIEW

14. OVERVIEW

15. OVERVIEW

16. STEPS IN TOOTH PREPARATION Occlusal guiding grooves Occlusal reduction Alignment grooves for axial reduction Axial reduction

17. STEPS IN TOOTH PREPARATION Breaking proximal contact Retentive grooves Finishing of the preparation

18. OCCLUSAL GUIDING GROOVES Burs for occlusal planar reduction: round-end tapered Round ended diamond bur used to prepare depth grooves Depth can be gauged with the diameter of the diamond point Occlusal depth grooves: 1.0-1.5 mm

19. OCCLUSAL REDUCTION 1.0-1.5 mm enamel chisel can be used for assessment of depth grooves Cuspal contours are followed and tooth morphology is maintained Functional cusp bevel: round end tapered bur

20. ALIGNMENT GROOVES: AXIAL REDUCTION AND FUNCTIONAL CUSP BEVEL Depth grooves for axial reduction using round end tapered bur Functional cusp bevel given at 1.5 mm depth at an angle of 45 degrees

21. ASSESSMENT OF OCCLUSAL CLEARANCE A small piece of utility wax used for assessment of occlusal clearance Translucent areas are indicative of inadequate preparation

22. AXIAL REDUCTION Facial and lingual reduction using torpedo diamond bur The reduction is done as facially and lingually as possible, without nicking the adjacent tooth

23. AXIAL REDUCTION Facial and lingual axial preparation and formation of proximal “lip”

24. BREAKING PROXIMAL TOOTH CONTACT Proximal contact broken with thin needle shaped point

25. PROXIMAL PREPARATION Proximal axial preparation continued with torpedo diamond point

26. FINISHING Finishing done with small grit diamond bur or carbide bur

27. FINISHING AND RETENTIVE GROOVES Additional grooves placed on mid-buccal surface to aid in retention

28. FINAL PREPARATION Final preparation of mandibular molar of full veneer metal crown Schematic representation

29. THANK YOU