STRUCTURAL DURABILITY

 

•      Occlusal reduction : One of the most important features for providing adequate bulk of metal and strength to the restoration is occlusal clearance.

•         For gold alloys- 1.5 mm clearance on the functional cusp (lingual of maxillary molars and premolars and buccal of mandibular molars and premolars ).

•         1mm clearance on the nonfunctional cusp.

 Occlusal Reduction   

 

•         The basic inclined plane pattern of the occlusal surface duplicated to produce adequate clearance without over shortening the preparation.

•         A flat occlusal surface may over shorten the preparation.

Inadequate Occlusal Reduction

•  Makes the restoration weaker.•         will not provide adequate space to allow good functional morphology under the anatomical grooves. 

• The restoration easily perforated by finishing procedures or by wear in the mouth.