| Project/Area Number |
14370624
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
補綴理工系歯学
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| Research Institution | Tohoku University |
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Principal Investigator |
KASAHARA Shin (2005) Tohoku University, Hospital, Lecturer, 病院, 講師 (70169407)
木村 幸平 (2002-2004) 東北大学, 大学院・歯学研究科, 教授 (40108551)
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| Co-Investigator(Kenkyū-buntansha) |
YODA Masanobu Tohoku University, Graduate School of dentistry, Associate professor, 大学院・歯学研究科, 助教授 (70005073)
KANNO Taro Tohoku University, Graduate School of dentistry, Assistant, 大学院・歯学研究科, 助手 (30302160)
OKUNO Osamu Tohoku University, Graduate School of dentistry, Professor, 大学院・歯学研究科, 教授 (50014080)
KIKUCHI Masafumi Tohoku University, Graduate School of dentistry, Assistant, 大学院・歯学研究科, 助手 (50250791)
HAYASHI Eisei Tohoku University, Hospital, Assistant, 病院・助手 (60375102)
笠原 紳 東北大学, 大学病院, 講師 (70169407)
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| Project Period (FY) |
2002 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥13,500,000 (Direct Cost: ¥13,500,000)
Fiscal Year 2005: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2004: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2003: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2002: ¥8,200,000 (Direct Cost: ¥8,200,000)
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| Keywords | Fe-Pt-Nb magnetic alloy / magnetic stainless steel / CAD / CAM / grindability / integral element method / magnetization / 有限要素法 / 磁性ステンレス綱 / 切削性 / 熱処理 / 磁気回路 / 可撤式歯科補綴装置 / クラウンブリッジ / クラウン・ブリッジ |
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| Research Abstract |
New prosthetic appliances composed of outer and inner crowns, each made of Fe-39.5mol%Pt-0.75mol%Nb magnetic alloy and magnetic stainless steel, have been developed. The Fe-Pt-Nb magnet has high energy product almost equivalent to the Sm-Co magnet, and excellent corrosion resistance. Kanno et al. showed the possibility of dental casting of the Fe-Pt magnet alloy. However, there remains a problem that the magnetic properties of the Fe-Pt-Nb magnetic alloy are very sensitive to the thermal history of the casting process.
Good grindability is desirable in magnetic alloys for clinical use. Furthermore, if the magnetic alloys could be readily machined by a dental CAD/CAM system, it would be possible to avoid problems related to melting the material, which are inevitable when casting. In this study, the grindability of the cast Fe-Pt-Nb magnetic alloy and the magnetic stainless steel was evaluated and compared with that of conventional dental casting alloys. Furthermore, using the integral el
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ement method, the 3-dimensional magnetic field of the outer and inner cap model were analyzed to determine the optimal method for the design and magnetization of removable crown and bridge system made of the Fe-Pt magnet.
CONCLUSION
1. There was no significant difference in the grinding rate between the solution treated and aged Fe-Pt-Nb magnetic alloys at 500 m min^<-1>. However, the grinding rate of aged Fe-Pt-Nb magnetic alloy was significantly lower at the higher grinding speeds.
2. It was found that the grinding rate of the aged Fe-Pt-Nb magnetic alloy and the stainless steel were higher than those of conventional casting alloys at lower speed.
3. When the thickness of outer cap top was 1.5mm and the length of outer cap side was 4.0-3.5mm, the optimum attractive force were obtained clinically.
4. The attractive force of model-1 was more excellent than that of model-2.
5. When the occlusal vertical dimension of the molar was low, it was suggested that the thickness of outer cap top was more important than the length of outer cap side in both models. Less
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