Influences of different opaque materials on stress occured after firing process at dental bridge production

In this study it was purposed that to examine the thermal stresses occured after firing process at dental bridge applications in changes of opaque material which is used as binding material between metal substructure and porcelain superstructure.First of all a four unit bridge model has been prepared by a dental laboratory. After that this model has been fired up to 9600C at a special oven which exist at our university?s mechanical department?s laboratory. At the end of this process, the oven?s door was opened in stages to get the model?s temperature to ambient temperature. With thermocouples connected to various points on dental bridge, temperatures of these points were saved in various times and we took out the cooling curves. With the help of these cooling curves, we calculated the equivalent heat transfer coefficient according to temperatures.Afterward this four unit?s model was built with SolidWorks and this model was imported to ABAQUS then made the analysis . The cooling curves were obtained numericaly by entering the calculated heat transfer coefficients to finite element analysis program. It has been seen that the cooling curves, we got from experimentally and we got from finite element analysis program, came close in enough ratios. Six kinds of opaque materials which shows diversity interms of thermal expansion coefficients were defined in the same model and thermal stresses which occured during cooling and at the end of cooling were compared. With this, we endeavored to fasten down the advantages of opaque materials to each others.