Cast clasp with good biocompatibility made by titanium

本研究的目的是探讨钛作为义齿材料的应用。这项研究涉及两个问题。一种是用商业钛焊料评估钛的铸造表面。二是探讨了热冲击法制备钛金属板材的可能性。钛铸件的表面质地低于其他牙科铸件。然而，含硅磷酸盐包埋的钛铸件表面明显比不含P和SiO_2包埋的钛铸件表面粗糙，而且钛铸件的表面织构与钴铬合金的表面织构几乎相同，因此认为钛铸件的质量仅取决于模具材料。此外，还研究了热震法制备钛铸板的应用。热冲击试验用于商业钛铸造系统(SELECT，SEEC)，包括作为复制品和作为模具的两种焊料(DM，D)。按制造说明书(STEP-1)、包括不经热处理的离合器(STEP-2)和造模前的复制(STEP-3)模具，在混合30min后制备，然后直接放入850℃预热的炉中。发现热冲击对STEP-1制造的模具是有效的。然而，复制品(步骤3)在放入炉子后几分钟内爆炸。通过控制预热温度在85 0℃以下或延长热启动时间，成功地避免了爆炸的发生，但冷却过程中裂纹大量扩展，对铸件造成危害。此外，我们还发现模具的干燥温度在100℃左右对热震是有益的。这些结果表明，热冲击可以有效地消除该系统的劳动时间，但在使用前应考虑预热温度和热启动时间等因素。

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.