Effect of Reduced Occlusal Thickness with Two Margin Designs on Fracture Resistance of Monolithic Zirconia Crowns.

Objectives:  The aim of this study was to compare the effects of two margin designs (shoulderless and slight chamfer) with two occlusal thicknesses on fracture resistance and failure mode of the monolithic zirconia crowns.

Materials And Methods:  Forty nickel-chromium dies were duplicated from the previous two prepared teeth using a three-dimensional optical scanner. Nickel-chromium supporting dies were divided into two main groups ( = 20) according to the type of margin design: group A, slight chamfer margin design and group B, shoulderless margin design.