Cast clasp with good biocompatibility made by titanium

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The purpose of this study was to investigate the application of titanium as denture material. There were two matters in this research. One was to evaluate the casting surface of titanium with commercial titanium investments. Another was to explore the possibility of heat-shock method when fabricating titanium metal plate. The surface texture of titanium cast was inferior to other dental casting metal. However, the surface of titanium cast obtained from phosphate-bonded investments with silica was obviously rougher than that of obtained from investments without P and SiO_2. In addition, these titanium cast was the almost same surface texture as Co-Cr alloy Thus, it was considered that the quality of titanium cast just depended on mold materials.Furthermore the application of a heat-shock method was also investigated when fabricating titanium cast plate. The heat shock was tried for a commercial titanium casting system (Selecast, selec) including two investments (DM, D) as a duplication and as a mold. The mold according to manufacture's instruction (Step-1), the mold including cluplication without a heat treatment (Step-2) and duplication itself before making the mold (Step-3) were prepared after 30min from mixing and then directly put into the furnace preheated at 850℃. The heat shock was found to be effective for the mold made by Step-1. However, the duplication (Step-3) exploded within a few minutes after placing in the furnace. This explosion was successfully avoided by the preheated temperature under 850℃ or prolonged heat-starting time, but a lot of cracks extended while cooling became the hazard for cast. Furthermore we found that the dry for the mold around 100℃ was useful for the heat shock. These results suggest that the heat shock was effective to eliminate the labor time for this system, but factors affecting such as the preheated temperature and heat-starting time should be considered prior to use.