Kim H, Johnson J W
West Virginia University, School of Dentistry, Department of Orthodontics, Morgantown, USA.
Angle Orthod. 1999 Feb;69(1):39-44. doi: 10.1043/0003-3219(1999)069<0039:COSSNT>2.3.CO;2.
Orthodontic wires containing nickel have been implicated in allergic reactions. The potential for orthodontic wires to cause allergic reactions is related to the pattern and mode of corrosion with subsequent release of metal ions, such as nickel, into the oral cavity. The purpose of this study was to determine if there is a significant difference in the corrosive potential of stainless steel, nickel titanium, nitride-coated nickel titanium, epoxy-coated nickel titanium, and titanium orthodontic wires. At least two specimens of each wire were subjected to potentiostatic anodic dissolution in 0.9% NaCl solution with neutral pH at room temperature. Using a Wenking MP 95 potentiostat and an electrochemical corrosion cell, the breakdown potential of each wire was determined. Photographs were taken of the wire speci mens using a scanning electron microscope, and surface changes were qualitatively evaluated. The breakdown potentials of stainless steel, two nickel titanium wires, nitride-coated nickel titanium, epoxy-coated nickel titanium, and titanium were 400 mV, 300 mV, 750 mV, 300 mV, 1800 mV, and >2000 mV, respectively. SEM photographs revealed that some nickel titanium and stainless steel wires were susceptible to pitting and localized corrosion. The results indicate that corrosion occurred readily in stainless steel. Variability in breakdown potential of nickel titanium alloy wires differed across vendors' wires. The nitride coating did not affect the corrosion of the alloy, but epoxy coating decreased corrosion. Titanium wires and epoxy-coated nickel titanium wires exhibited the least corrosive potential. For patients allergic to nickel, the use of titanium or epoxy-coated wires during orthodontic treatment is recommended.
含镍的正畸钢丝与过敏反应有关。正畸钢丝引发过敏反应的可能性与腐蚀模式及方式有关，随后金属离子（如镍）会释放到口腔中。本研究的目的是确定不锈钢、镍钛合金、氮化物涂层镍钛合金、环氧涂层镍钛合金和钛正畸钢丝的腐蚀电位是否存在显著差异。每种钢丝至少取两个样本，在室温下于pH值为中性的0.9%氯化钠溶液中进行恒电位阳极溶解。使用温金MP 95恒电位仪和电化学腐蚀池，测定每种钢丝的击穿电位。使用扫描电子显微镜拍摄钢丝样本的照片，并对表面变化进行定性评估。不锈钢、两种镍钛合金钢丝、氮化物涂层镍钛合金、环氧涂层镍钛合金和钛的击穿电位分别为400 mV、300 mV、750 mV、300 mV、1800 mV和>2000 mV。扫描电子显微镜照片显示，一些镍钛合金和不锈钢钢丝易发生点蚀和局部腐蚀。结果表明，不锈钢容易发生腐蚀。不同供应商的镍钛合金钢丝的击穿电位存在差异。氮化物涂层不影响合金的腐蚀，但环氧涂层可降低腐蚀。钛钢丝和环氧涂层镍钛合金钢丝的腐蚀电位最低。对于对镍过敏的患者，建议在正畸治疗期间使用钛钢丝或环氧涂层钢丝。
