| Project/Area Number |
61870081
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
補綴理工系歯学
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| Research Institution | OSAKA DENTAL UNIVERSUTY |
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Principal Investigator |
KAWAZOE Takayoshi OSAKA DENTAL UNIVERSITY PROF, 歯学部, 教授 (50076022)
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| Co-Investigator(Kenkyū-buntansha) |
OHTSUKA KIYOSHI OSAKA DENTAL UNIVERSITY ASSIST., 歯学部, 助手 (30160542)
SUESE KAZUHIKO OSAKA DENTAL UNIVERSITY ASSIST., 歯学部, 助手 (20140212)
TOGAYA TOSHIHIRO KYOTO UNIVERSITY ASSIST., 医用高分子研究センター, 助手 (50127106)
TANI YOSHIAKI KYOTO ONIVERSITY ASSIST,PROF., 医用高分子研究センター, 助教授 (90026881)
IDA KAZUO KYOTO UNIVERSITY PROF., 医用高分子研究センター, 教授 (90028720)
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| Project Period (FY) |
1986 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥9,500,000 (Direct Cost: ¥9,500,000)
Fiscal Year 1987: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1986: ¥7,600,000 (Direct Cost: ¥7,600,000)
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| Keywords | Titanium Casting / Casting Defects / Dimensional Fitness / Zirconium Metal powder / Oxidation Expansion / Internal Porosities / Castability |
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| Research Abstract |
1) Internal porosities
The amount of prosity of titanium casting was estimated from the densi determination of any specimen,and radiographic examinations were employed to observe the internal porosities of the casting.
The amount of porosity was independent on the mold temperature and the magnitude of the casting pressure. Hoeever,it was markedly influenced by the permeability of the mold materials and the suction during the application of castig pressure. It was showed that the amount the porosity decreased with decreasing the permeability of the mold materials. In the case of the high permeability mold materials,the casting pressure with suction developed the internal porosities much more than without suction.
2) Gastability
The castability values of pure titanium was lower at room temperature than at 8000゜C. Increasing the casting pressre caused an increase in the castability value and the suction was effective on the gain. The value decreased as the permeability of the mold materials w
… More
as lowered.
These result suggest that the casting procedure for preventing the porosities of titanium castings is unsuitable for increasing the castability. Therefore,it is most effective to apply the large castung perssure without suction. Employing a diaphram between the melting chamber and the casting chamber of the vacuum!argon pressure casting machine was very effective on the gain of the castability.
3) Improvement of fitness on castings
The practical improvement of dimensional fitness between titanium castin and abutment was achieved by the oxidizing expansion of Zr metal powder mixed in a magnesia invesment during firing up to 800゜C. This magnesia investment was used as a face-coating investment and the dental phosphate-bonded investment was used as a outer investment for the titanium casting crown.
4) Glinical application of pure titanium restoration
Since 1982,more than one hundred restorations of pure titanium have bee used chinically. There were no problem in the adhesion of plaque, discoloration and occlusal wear to the titanium restorations.
There were useful for prosthodontic evaluation in retentive condition on resin veneered titanium cast crown,and bending strength and corrosion on titanium post core. Less
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