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Studies on super-elastic NiTi alloy square and rectangular wires for orthodontic use. 1 Mechanical properties.

1987; Volume: 54; Issue: 1 Linguagem: Inglês

10.5357/koubyou.54.57

1884-5185

Yasuo Okamoto,

Shape Memory Alloy Transformations

In the study on the orthodontic wires, the NiTi alloy is highlighted these days. It is noticed because of the special properties, i. e; the shape memory effect and super-elasticity as well as the excellent spring-back property. Dr. Ohura and others reported that the Japanese NiTi alloy round wire produced by Furukawa Electric Co., Ltd. has these properties. The purpose of this study is to clarify the mechanical properties of the square and rectangular wires fabricated by this NiTi alloy for orthodontic use. Three-point bending tests and torque tests were examined and the results obtained were as follows: 1) The square and rectangular wires showed a super-elastic property in both the bending tests and torque tests, 2) The level of the super-elasticity could be decreased by heat treatment, and 3) With the increase of the heating time, the area which showed super-elasticity shifted to the left and the longer the heating time, the less the effect on the load decrease. By using the mechanical properties of these wires, it will be possible to manage the threedimensional tooth movement involving the torque from the early stage of orthodontic treatment.