| Project/Area Number |
17592145
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Orthodontic/Pediatric dentistry
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| Research Institution | Health Sciences University of Hokkaido |
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Principal Investigator |
IIJIMA Masahiro Health Sciences University of Hokkaido, Department of Orthodontics, Associate Professor, 歯学部, 准教授 (20305915)
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| Co-Investigator(Kenkyū-buntansha) |
MIZOGUCHI Itaru Health Sciences University of Hokkaido, Department of Orthodontics, Professor, 歯学部, 教授 (20200032)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2006: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2005: ¥2,900,000 (Direct Cost: ¥2,900,000)
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| Keywords | archwire / be ta-Ti / Ni-Ti / laser-welding / Micro-XRD / tension test |
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| Research Abstract |
Laser welding 0.016×0.022 inch beta-Ti, Ni-Ti and Co-Cr-Ni orthodontic wires was investigated by measuring joint tensile strength, measuring laser penetration depth, determining metallurgical phases using Micro-XRD, and examining microstructures with an SEM. Welding was performed at voltages from 150 to 230 V. Mean tensile strength for Ni-Ti groups was significantly lower (P < 0.05) than for most other groups of laser-welded specimens. Although mean tensile strength for beta-Ti and Co-Cr-Ni was significantly lower than for control specimens joined by silver soldering, it was sufficient for clinical use. The beta-Ti orthodontic wire showed deeper penetration depth from laser welding than the Ni-Ti and Co-Cr-Ni orthodontic wires. Micro-XRD patterns of laser-welded beta-Ti and Ni-Ti obtained 2 mm from the boundary were similar to as-received specimens, indicating that original microstructures were maintained. When output voltages of 190 V and higher were used, most peaks from joint areas disappeared or were much weaker, perhaps because of a directional solidification effect, evidenced by SEM observation of fine striations in welded beta-Ti. Laser welding beta-Ti and Co-Cr-Ni wires may be acceptable clinically, since joints had sufficient strength and metallurgical phases in the original wires were not greatly altered
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