Grant-in-Aid for Scientific Research (B)
|Research Institution||Tokyo Medical and Dental University|
SOMA Kunimichi Tokyo Medical and Dental University, Faculty of Dentistry, Professor, 歯学部, 教授 (10014200)
植木 達彦 古河電気工業(株), 研究員
YONEYAMA Takayuki Tokyo Medical and Dental University, Institute for Medical and Dental Enginecrin, 医用器材研究所, 助教授 (00220773)
野田 隆夫 東京医科歯科大学, 歯学部, 助手 (10251539)
OTSUBO Kunihiko Tokyo Medical and Dental University, Faculty of Dentistry Assistant Protessor, 歯学部, 助手 (20272601)
UEKI Tatsuhiko Furukawa Elcctric co., Itd.
|Project Fiscal Year
1997 – 1998
Completed(Fiscal Year 1998)
|Budget Amount *help
¥11,800,000 (Direct Cost : ¥11,800,000)
Fiscal Year 1998 : ¥7,400,000 (Direct Cost : ¥7,400,000)
Fiscal Year 1997 : ¥4,400,000 (Direct Cost : ¥4,400,000)
|Keywords||Ti-Ni alloy / super-elastic / orthodontic wire / bending test / Co-Cr alloy / stainless steel / heat treatment / hollow wire / Ti-Ni合金 / 超弾性 / 矯正用ワイヤー / 曲げ試験 / Co-Cr合金 / ステンレス鋼 / 熱処理 / 中空型ワイヤー|
Bending characteristics of two different diameters-O.016 and 0.018 inch-of hollow Ti-Ni alloy wire ; which are widely used in the medical field, and a coupling Ti-Ni and Co-Cr wire were investigated by three-point bending test at 37ﾟC.The coupling wire was made by inserting a 0.010 inch or 0.012 inch CO-Cr wire to a hollow Ti-Ni wire.
First, heat treatment of the hollow Ti-Ni wires was performed in a nitrate salt bath for 30mm. The temperature ranged between 400-650ﾟC.
From a load-deflection curve, in heat treatment temperature of 40O-600ﾟC, the super elastic property was shown and there was very little plastic deformation.
However, when the temperature exceeded 600ﾟC, some plastic transformation was found.
A smallest load level was obtained by heat treatment at 450ﾟC, and the biggest load level was obtained at 600ﾟC.
Moreover, the load level of the hollow-type wire was lower than that of the conventional Ti-Ni alloy wire and the stress hysterisis was shown to be only 65% of the conventional wire.
From the above, findings, the light constant force to move teeth can be generated during the initial stage of orthodontic treatment without the need to reduce an archwire size.
A coupling wire that inserted Co-Cr alloy wire to a hollow super-elastic Ti-Ni alloy wire was shown to have stiffness of 2 times.
In the later stage of orthodontic treatment, when retraction of anterior teeth and bite raising are performed, the archwire which has high stiffness is required. By using the coupling wire, it is possible to increase the stiffness without changing the archwire.
At present, a new torquing and bending test device is still in developing process.
Evaluation of the force produced by torquing and bending of a hollow Ti-Ni alloy rectangular wire is planned.