Studies on Dental Precision Casting Titanium Alloys

Research Project

Project/Area Number	60480421
Research Category	Grant-in-Aid for General Scientific Research (B)
Allocation Type	Single-year Grants
Research Field	補綴理工系歯学
Research Institution	Tokyo Medical and Dental University
Principal Investigator	MIURA Ishi Professor, Institure for Medical and Dental Engineering, Tokyo Medical and Dental University, 医用器材研究所, 教授 (90014068)
Co-Investigator(Kenkyū-buntansha)	OKUNO Osamu Assistant Professor, ibid., 医用器材研究所, 助手 (50014080) HAMANAKA Hitoshi Associate Professor, ibid., 医用器材研究所, 助教授 (10013955) 森福孝東京医科歯科大学, 医用器材研究所, 助手 (70126259)
Project Period (FY)	1985 – 1987
Project Status	Completed (Fiscal Year 1987)
Budget Amount *help	¥5,900,000 (Direct Cost: ¥5,900,000) Fiscal Year 1987: ¥900,000 (Direct Cost: ¥900,000) Fiscal Year 1986: ¥900,000 (Direct Cost: ¥900,000) Fiscal Year 1985: ¥4,100,000 (Direct Cost: ¥4,100,000)
Keywords	Dental Casting Alloys / Titanium Alloys / Dental Casting Machine / Titanium Casting / Ti / Pd alloys / チタン-パラジウム合金 / チタン-クロム合金 / 遠心鋳造
Research Abstract	Titanium has various advantages for dental prosthetic metals, such as excellent corrosional resistance, biocompatibility, and light weight. But it is not so easy to cast pure titanium by usual dental casting methods. The problems were solved by developing new dental titanium alloys and new casting machine for dental casting. The titanium alloy investigation evaluated compositions from nine <beta>-titanium systems. It was found in these systems that Ti-Cr-Si alloy and Ti-Pd-Cr alloy have a lower melting point, les reactivity with phosphate bonded investment and good mechanical properties. These castings have almost the same castability and surface roughness as Ni-Cr alloys and Co-Cr alloys. The fitness is better than dental base metal alloys. The tensile strength of the tita-nium alloys varied from 790 to 940 MPa. The elongation was 4% or more, The titanium alloys have a hardness about one-third greater than type IV gold alloys. The results show that Ti-Pd-Cr and Ti-Cr-Si were suitable for bridge, clasp, partial denture and full denture from the mechanical properties. The casting machin has small melting and casting chamber which is spined by motor. A mold is set sideway of calcia cruncible on the sprue, and the titanium alloy is put in the cruncible, Afterthe air is exhausted, argon gas is fed to the chamber. The alloys are melted by argon arc. Immedi-atly after the alloys are melted, they are cast by centrifugal force. The alloys can be melted and cast in completely inert atmosphere,