Finite element analyses of firing behavior of metal-ceramic crown margins
AbstractConsidering the deformations appeared after the firing process of ceramic, we tried to establish if there is any relation between these and the type of peripheral preparation, on the one hand, and the coefficient of thermal expansion of metal and porcelain, on the other hand.The study is original and was conducted in COSMOS DesignSTAR, consisting in finite element analysis of firing process. The tested objects were created in RhinoCeros Nurbs modeling for Windows, version 4.0. It consists of three models, each one with abutment, metal cape and ceramic veneer, but with different type of peripheral preparation: shoulder with metal collar, shoulder without metal collar and chamfer with metal collar.The results suggested that the shoulder without metal-collar model recorded the highest marginal distortion and the chamfer model the smallest, and the higher the difference between thermal expansion coefficients the higher the marginal distortion .
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