Liu I H, Lee T M, Chang C Y, Liu C K
Institute of Oral Medicine, National Cheng Kung University, Tainan, Taiwan, ROC.
J Dent Res. 2007 Jun;86(6):539-43. doi: 10.1177/154405910708600610.
For dental orthodontic applications, NiTi wires are used under bending conditions in the oral environment for a long period. The purpose of this study was to investigate the effect of bending stress on the corrosion of NiTi wires using potentiodynamic and potentiostatic tests in artificial saliva. The results indicated that bending stress induces a higher corrosion rate of NiTi wires in passive regions. It is suggested that the passive oxide film of specimens would be damaged under bending conditions. Auger electron spectroscopic analysis showed a lower thickness of passive films on stressed NiTi wires compared with unstressed specimens in the passive region. By scanning electron microscopy, localized corrosion was observed on stressed Sentalloy specimens after a potentiodynamic test at pH 2. In conclusion, this study indicated that bending stress changed the corrosion properties and surface characteristics of NiTi wires in a simulated intra-oral environment.
在口腔正畸应用中，镍钛丝在口腔环境中长时间处于弯曲状态下使用。本研究的目的是通过在人工唾液中进行动电位和恒电位测试，研究弯曲应力对镍钛丝腐蚀的影响。结果表明，弯曲应力会使镍钛丝在钝化区域的腐蚀速率更高。这表明试样的钝化氧化膜在弯曲条件下会受到破坏。俄歇电子能谱分析显示，与未受力的试样相比，受力镍钛丝在钝化区域的钝化膜厚度更低。通过扫描电子显微镜观察到，在pH值为2的动电位测试后，受力的Sentalloy试样上出现了局部腐蚀。总之，本研究表明弯曲应力在模拟口腔环境中改变了镍钛丝的腐蚀性能和表面特性。
