Monday, February 23, 2015

Class II cavity preparation ,mistakes to avoid




The class II amalgam cavity preparation consists of
 A -Occlusal segment ( portion)
 B- Proximal segment (portion)

In this post we will  display the common mistakes made by students concerning the class II cavity preparation

A- The occlusal segment 

The occlusal segment follows the same fundamentals already given for the class I amalgam except that the external outline is extended proximally toward the proximal surface.

IDEAL EXTENSION





COMMON  MISTAKES

 


              Under extended                                   over extended


 IDEAL  OCCLUSAL OUTLINE FORM in upper molar   ( notice the curve)



COMMON MISTAKES

 



                                           

 
B-The Proximal segment

 IDEAL  DIRECTION  OF WALLS



COMMON MISTAKES


 


 IDEAL DEPTH ( NOTICE THE PREPARATION OF THE MARGINAL RIDGE)



 


COMMON MISTAKES




 


Use of the hand instrument


 

RETENTION


COMMON MISTAKES


Excess Flare



                                 Horizontal section

Lack of flare


                                Horizontal section

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