RETENTION

Surface area

 

 Same width but different height  

 

Same height but different width

 

        

STRUCTURAL DURABILITY

•    Restoration must contain bulk of material that is adequate to withstand the forces of occlusion.

•         This bulk must be confined to the space created by the tooth preparation.

•         Only this way the occlusion will be harmonious and axial contours normal.

STRUCTURAL DURABILITY

 1.  Occlusal  Reduction. 

 2.  Functional Cusp Bevel. 

 3.  Axial reduction