|Budget Amount *help
¥3,200,000 (Direct Cost : ¥3,200,000)
Fiscal Year 1998 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1997 : ¥2,600,000 (Direct Cost : ¥2,600,000)
Applied frequency to the odontology department area of the commercial pure titanium increases along with the improvement of the casting technology which is one of big problems which should be solved, and the demand of the commercial pure titanium casting denture has risen. However, a further improvement is requested about the dimensional accuracy. In this time authors paid attention as one factor taking part in the deformation and the adaptability of the commercial pure titanium casting denture to the form of the retentional lattice. Authors experimented to grope for the forms of a ideal retentional lattice. In the 1st experiment, authors examined both of the pattern that the outline stops in the alveolous top and the pattern that the alveolous top crosses over 10mm about the type of the holded none, the mesh type, and the ladder type. The discrepancy of the palate when exceeding outward from the alveolus top by 10mm of the type of the holed none was large. I was able to ask about the
case to stop in the alveolus top, excess from the alveolus top by 10mm, and both horizontal planes and frontal sides were displaced right, and the deformation of the titanium casting denture be large to the type of the holed none. The difference of the expansion shrinkage of length and horizontal direction was large in the ladder type. Moreover, after the palate, the discrepancy of the edge part indicated the value with the biggest ladder type when exceeding outward from the alveolus top by 10mm. As for the ladder type as the retentional lattice, an excellent result was not obtained. The mesh type obtained the result in which the difference of the expansion shrinkage of length and horizontal direction was small, and excellent. The best type is that retentional lattice is the mesh type and the outline stops in the alveolus top. Then, authors have done the 2nd experiment to grope for a better mesh type. In the 1st experiment , it was suggested that the investment which existed in the hole of the mesh type influence the casting shrinkage of titanium. Therefore, the sample that the size, number, and the arrangement of the hole of the mesh were changed was manufactured.
As a result, in the condition of that the size of mesh was enlarged, and the position was given outside from the usual one, authors obtained the casting denture with little dimensional changes. Less