Orthodontic Application of NiTi Shape-Memory Alloy in China

Abstract

Based on the finding of unique superelasticity of NiTi shape memory alloy [1], a Nitinol wire was introduced for orthodontic usage by Andreasen et al. in 1971 [2]. In the beginning of the 1980s, NiTi orthodontic archwires started being produced commercially for clinical use in China [3]. Due to NiTi’s superior performance over traditional wires made of stainless steel, NiTi orthodontic devices have become the naterial of choice in the initial correction of dental malocclusion. In recent years, the domestic demand for the NiTi orthodontic products grew rapidly, increasing annuallly at a rate of 30-40%. A production line for NiTi wires has been set up in the Shape Memory Centre of Beijing’s General Research Institute for Nonferrous Metals (BGRINM) with annual production of many million sets of orthodontic wires. This centre is proud to have already achieved ISO9001 certification. The production of this line accounts for an overwhelming share of the Chinese market of NiTi orthodontic devices, and a certain amounts of the products are being been exported abroad. Improvements of these NiTi orthodontic devices include : material quality, heat treatment, size, shape and performances [4,5]. Now a variety of NiTi orthodontic products are available to meet different clinical requirements, and will be described below.