| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2002: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2001: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
The purpose of this study is to establish the polishing method of titanium crown using a centrifugal shooting type polishing system. First the polishing effect of abrasive grain that contained diamond powder was examined. Casting pure titanium specimens were polished using this apparatus. Three various abrasive grains were used for polishing, that is, green carborundum (GC), green carborundum contained 20wt% diamond powder (D20%) and green carborundum contained 40wt% diamond powder (D40%). After polishing the surface roughness of specimen was measured. As a result, the value of surface roughness in D20% or D40% was lower than that in GC, however, the difference between D20% and D40% was not recognized.
Then the influence of polishing using this apparatus on titanium crown margin was examined. Wedge shaped specimens of pure titanium and Ti-6A1-7Nb alloy assuming crown margin were prepared. Tip angle of the specimen was taken as 30, 45 and 60 degree, and polishing time was set 40, 60 and 90 seconds. After polishing the marginal reduction of each specimen was measured. As a result, in both of these experimental metals the tip angle of the specimen had little effect on the marginal reduction. The marginal reduction significantly increased as polishing time increased, however, the value was very low, that is, a maximum of 15μm. This suggested that polishing using a centrifugal shooting type polishing system had little influence on titanium crown margin.
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