Cioffi M, Gilliland D, Ceccone G, Chiesa R, Cigada A
Dipartimento di Bioingegneria, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milano, Italy.
Acta Biomater. 2005 Nov;1(6):717-24. doi: 10.1016/j.actbio.2005.07.008. Epub 2005 Oct 5.
Alloys based on Ni-Ti intermetallics generally exhibit special shape memory and pseudoelastic properties, which make them desirable for use in the dental field as orthodontic wires. The possibility of nickel release from these materials is of high concern, because the allergenicity of this element. The aim of this study was to test pseudoelastic Ni-Ti wires in simulated physiological conditions, investigating the combined effect of strain and fluoridated media: the wires were examined both under strained (5% tensile strain) and unstrained conditions, in fluoridated artificial saliva at 37 degrees C. Real time electrochemical nickel release testing was performed using a novel application of a radiotracer based method, thin layer activation (TLA). TLA was validated, in unstrained conditions, against adsorptive stripping voltammetry methodology. Control tests were also performed in non-fluoridated artificial saliva. From our research it transpired that the corrosion behaviour of Ni-Ti alloy is highly affected by the fluoride content, showing a release of 4.79+/-0.10 microg/cm2/day, but, differently from other biomaterials, it does not seem to be affected by elastic tensile strain. The application of the TLA method in the biomedical field appears a suitable technique to monitor in real time the corrosion behaviour of biomedical devices.
基于镍钛金属间化合物的合金通常表现出特殊的形状记忆和伪弹性性能，这使得它们作为正畸钢丝在牙科领域具有应用价值。这些材料释放镍的可能性备受关注，因为该元素具有致敏性。本研究的目的是在模拟生理条件下测试伪弹性镍钛丝，研究应变和含氟介质的综合影响：在37℃的含氟人工唾液中，对钢丝在拉伸应变（5%拉伸应变）和无应变条件下进行检测。使用基于放射性示踪剂的方法——薄层活化（TLA）的新应用进行实时电化学镍释放测试。在无应变条件下，通过吸附溶出伏安法对TLA进行了验证。还在非含氟人工唾液中进行了对照试验。从我们的研究中发现，镍钛合金的腐蚀行为受氟含量的影响很大，释放量为4.79±0.10微克/平方厘米/天，但与其他生物材料不同的是，它似乎不受弹性拉伸应变的影响。TLA方法在生物医学领域的应用似乎是一种实时监测生物医学装置腐蚀行为的合适技术。
