Information about the effect of occlusal preparation designs on the stress distribution in different ceramic crowns and the prepared tooth is limited.

The purpose of this study was to investigate the effects of anatomic and nonanatomic occlusal preparation designs on the stress distribution in ceramic crowns, teeth, and bone.

Finite element analysis was performed on models of a mandibular second premolar. A load of 400 N was applied to the models to test ceramic materials (In-Ceram, Empress Esthetic) and occlusal preparation (anatomic, nonanatomic) designs.

The lowest stress value occurred in the core material in the Empress Esthetic model prepared with the nonanatomic occlusal preparation design. In all groups, higher stress values were found to be concentrated in the lingual half of the dentin. Lower stress values were located near the apex of the pulp tissue and bony tissue that surround the root apex.

Differences in preparation designs did not result in differences in the distribution or amount of stress in pulp, dentin, or bone. The use of different ceramic materials resulted in no differences in the amount or distribution of stress in pulp and bone. The use of a crown with a high elastic modulus led to increases in stress values in the restoration and the dentin margin, and decreases in stress values in the occlusal surface of the dentin. The nonanatomic design can be recommended as a favorable preparation design for Empress Esthetic ceramic.