📃 PREPARATION CONCEPT ❗️
Proper tooth preparation is accomplished through systematic procedures based on specific physical and mechanical principles. A prerequisite for understanding tooth preparation is knowledge of the anatomy of each tooth and its related parts. A mental image of the individual tooth being prepared must be visualized. The direction of the enamel rods, the thickness of enamel and dentin, the size and position of the pulp, the relationship of the tooth to its supporting tissues, and other factors all must be considered to facilitate appropriate tooth preparation.
There are important factors to successful clinical outcome :-
1-ANGULATIONS
2-DIMOND TIP DESIGN
3-INSERTION AXIS
4-ROUNDED ANGLES
5-INCISAL CUT
6-FINISH DESIGN
References
1. Miller M. The Techniques. Houston, Tex: Reality Publishing Co; 2003.
2. Shillingburg HT Jr, Jacobi R, Brackett SE. Fundamentals of Tooth Preparations for Cast Metal and PorcelainRestorations. Carol Stream, Ill: Quintessence Publishing Co; 1987.
3. Dawson PE. Evaluation, Diagnosis, and Treatment of Occlusal Problems. 2nd ed. St Louis, Mo: Mosby-Year Book;
1989: 7-13, 274-297, 470-476.
Labial reduction
Position of Depth diamond bur
Incisal reduction
3 depth line in incisal egde as a guide
Position of taper diamond bur
ANGULATIONS
Evaluation of the degree of taper and convergence angle of full crown preparations
Position of taper diamond bur to achieve optimal taper
Interproximal reduction
DIMOND TIP DESIGN
Path of insertion
Must be Parallel to the long axis of tooth
ROUNDED ANGLES
For all crowns it is critical to round all internal line angles with one of the fine diamonds; this minimizes stress concentrations in the crown by eliminating sharp angles
Incisal cutting
Must be striaght line to achieve 90 degree to axis
Chamfer finish line must be clear and continuous all around
Outline surface finish
Share on:
