Preparation Steps

Occlusal clearance (reduction)
External retention form and finish lines
Auxiliary retention
Finishing bevels

Retention Form


Length of walls:Minimum Length 3 mm.
Taper of walls: Ideal Taper 6 Degrees Between Opposing Walls
Circumference.

Finish Lines


Occlusal Reduction

1.5 mm clearance in all areas
Follow original occlusal planes
Reduction parallels opposing triangular ridges







Functional Cusp Bevel


1.5 mm clearance
Parallels opposing triangular ridges






Axial Reduction & Chamfer:


Axial walls at least 3 mm long
6-10 degree taper between opposing walls
Chamfer depth from 0.3-0.7 mm
Even axial depth
Follow gingival contours
Finish line 0.5 mm supragingival


Line Of Draw

IMAGINARY line
BEFORE preparation is begun
CENTER of all possible paths of withdrawal or seating of the restoration





Interproximal Reduction

Extend below adjacent tooth contact
Avoid
Adjacent tooth damage
Overtapering
Excessive axial reduction




Non Functional Cusp Bevel

0.2-0.3 mm wide


Burs


57-010 Carbide Occlusal
878K-012 Diamond Axial
850-012 Diamond Interproximal
7404F-014 Carbide Contrabevel