| In dental grinding of bioceramic restorations using dental high-speed handpiece, the machining-induced thermal problems could not be ignored, because that the high temperature in dental grinding of ceramics would not only bring pains to patients, but also cause damage in ceramic restorations resulting in a reduction in strength and lifetime of the restiorations. In this dissertation, the important process parameters related with force and temperature during the in vitro dental grinding of bioceramics using a high-speed electric handpiece and diamond burs were investigated with the help of the National Natural Science Foundation of China. The following work and the results are drawn:(1) First author used high-speed electric handpiece to replace the traditional air-turbine handpiece, and then measured and analyzed the grinding force signal in the progress of grinding dental ceramics using an electric handpiece and diamond burs. Surface roughness and morphology were observed by a stylus profilometer and scanning electron microscope. At last, author investigated grinding forces and surface quality under different grinding parameters, and assessed the grinding performance of the electric handpiece.(2) Grinding forces and grinding temperature when using an electric handpiece to grind dental ceramics were measured by a piezoelectric force dynamometer and a thermal infrared imager. Then analyzed the grinding temperature under the different grinding parameters with single factor analysis method, the result would provide the dentists with positive suggestions to reduce the pain and heat damage.(3) The temperature field in grinding dental ceramics was numerical analyzed using finite element analysis methd, and important influential factors were analyzed.The experimental temperature and simulated temperature were compared and the result were consistent. It indicates that the heat source simulation was correct. The above results provide theoretical and experimental basis to proper intraoral dental grinding of ceramic restorations. |
