Simulating clinical fractures of all-ceramic crowns -

Fractographic analyses of all-ceramic crowns that have failed during clinical use show different fracture features compared with those commonly observed in laboratory studies. Until now, in vitro tests which have been published usually show contact damage induced at the loading point – occlusally for molars and premolars and lingually for incisors. Clinically failed crowns, on the other hand, seem to fracture from cracks initiated in the cervical margin in the core material, usually in the approximal region.