Studies on the Tumorgenicity of Titanium Alloys for Dental Implants

为明确牙科种植体用钛合金的致瘤性，研究了氨基酸溶液对这些合金的溶解性和释放物的致突变性。1）将NiTi、Ti6 A14 V、Ti5A12.5Fe和Ti 5A 13 Mo 4 Zr四种合金用冷冻粉碎机粉碎成细粉。将300 mg每种粉末浸入5 ml 0.1 M半胱氨酸溶液或0.1 M谷胱甘肽溶液中，在37 ℃下以15 rpm的速度旋转。2周后，通过原子吸收分光光度计或电感耦合等离子体发射光谱仪（ICP）分析浸提液中的Ti、Al、V、Fe、Mo和Ni。从Ti6 A14 V合金到谷胱甘肽溶液中的Ti、Al和V的平均泄漏分别为31.6、400和79.6pg/mg合金/天。半胱氨酸溶液中钛的平均泄漏量为1.5 pg/mg合金/天。2）研究了暴露于浸提液的HeLa细胞的非程序DNA合成（UDS）频率。3）研究了不同浓度浸提液对V79细胞姐妹染色单体交换（SCE）的影响。用Ti 5A 13 Mo 4 Zr合金的谷胱甘肽提取物处理的V79细胞中SCE的频率比谷胱甘肽溶液对照增加约3倍。可以证明SCE显著增加。发现了钛合金溶解物的遗传效应。

To clarify the tumorgenicity of titanium alloys for dental implants, the dissolution of these alloys immersed in amino acid solutions and mutagenicity of the released substances from the alloys were studied.1) Four alloys, NiTi,Ti6A14V, Ti5A12.5Fe and Ti5A13Mo4Zr were grinned to a fine powers using a freeze mill. Three hundred mg of each powder was immersed in 5 ml of 0.1M cysteine solution or 0.1M glutathione solution under rotation at speed of 15rpm at 37ﾟC. After 2 weeks, the extracts were analyzed of Ti, Al, V, Fe, Mo and Ni by an atomic absorption spectrophotometer or Inductively Coupled Plasma emission spectrometer (ICP). The average leakage of Ti, Al and V from Ti6A14V alloy to glutathion solution were 31.6, 400 and 79.6 pg/mg of alloy/day respectively. The average leakage of Ti to a cysteine solution was 1.5 pg/mg of alloy/day.2) The frequency of the Unscheduled DNA Synthesis (UDS) were studied in HeLa cells exposed to the extracts. No significant increase in the frequency of UDS were observed.3) The frequency of exchange of Sister Chromatides (SCEs) were studied in V79 cells exposed to the extracts. The frequency of SCEs in V79 cells treated with glutathione extracts of a Ti5A13Mo4Zr alloy were increased about 3 times that a glutathione solution control. A significant increase in SCEs could be demonstrated. The genetic effects of titanium alloys dissolved substances are found.