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.