Background& Objective: This study was carried out to test fracture resistance of crowns with Zirconia
core made by CAD/CAM of two thicknesses, and test the influence of decreasing the core thickness on its
fracture resistance, and study the patterns of failure.
The idea of use ceramic margins for metal-ceramic crowns was founded to
overcome problem of grayness for gingival margins that caused by metal collar in metal-ceramic crowns ,
but at the same time there are a lot of cautions on decrease mechanical
resistance for these restorations.
This study aims to study fracture resistance of metal-ceramic crowns with ceramic margins in 1 or 2 mm.
long, and compare it with mechanical resistance of metal-ceramic crowns with metal collar.
Zirconia-based fixed dental prostheses have been suggested for use
in the posterior regions of the mouth as an alternative to traditional
metal ceramic FDPs because of its favorable mechanical properties0
The effect of framework design modificatio
ns in zirconia-based
FDPs is not fully understood. The aim of this study is to compare
the fracture resistance of Y-TZP zirconia FDPs with two different
framework design.
