The study revealed major deficiencies for both Norwegian and overseas made crowns regarding conformity between composition and the stated declaration

Different dental ceramics available today including a classification, mechanical properties and a description of processing techniques with emphasis on the zirconia materials.

Fracture strength measured in vitro indicates that most all-ceramic crowns should be able to withstand mastication forces. Nevertheless, fractures are one of the major clinical problems with all-ceramic restorations. Furthermore, the fracture mode of all-ceramic crowns observed in clinical use differs from that found in conventional fracture strength tests. The aim of the present study was to develop and investigate a method that simulates clinical fracture behavior in vitro