Nickel-titanium(NiTi) alloy wires are now widely used in the medical field because of their unique shape memory effect and superelasticity.
The purpose of this study is to investigate the effects of mechanical fatigue and thermal cycling fatigue in orthodontics NiTi wire. The fatigue test was performed by three point bending fatigue test(No. of 4000, 8000, 12000, 16000) and
tension-compression fatigue test(No. of 1000, 2000, 3000, 4000) and thermal cycling fatigue test(No. of 500, 1000).
@ES The results were as follows:
@EN 1. Strength, orthodontic force and transformation temperature(As, Af) were decreased with increasing number of fatigue cycle due to the coarsening of precipitations and increased density of dislocations.
2. Orthodontic force was slightly increased with number of cycle in thermal cycling fatigue due to the cohesion of precipitation and high density of dislocations.
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