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目的评价3种正畸用镍钛形状记忆合金弓丝的细胞毒性。方法于2009年11月至2010年3月,在中国医科大学口腔医学院选择正畸临床常用的3种品牌镍钛形状记忆合金弓丝(A:Masel牌美国产热激活型镍钛牙齿矫形丝;B:Smart牌国产热激活型镍钛牙齿矫形丝;C:有研亿金牌国产镍钛丝),制作试件各若干枚,长度0.5cm。将其依次分为3份,一份处理后直接提取浸提液;另外两份处理后置于人工唾液中浸泡,分别于4周和8周后取出提取浸提液。选择L-929细胞系作为细胞毒性的实验对象,用倒置相差显微镜观察L-929细胞在合金丝浸提液中的生长情况,通过四甲基偶氮唑盐微量酶反应比色法(MTT法)得出细胞在培养24h和48h的吸光度(OD)值以及细胞相对增殖率(RGR),对3种品牌镍钛形状记忆合金弓丝做出细胞毒性评价。结果在人工唾液浸泡后,3种品牌镍钛形状记忆合金弓丝的细胞毒性均随浸泡时间延长而逐渐增加(P<0.05);在相同的浸泡时间下,A弓丝的细胞毒性最小,C弓丝的细胞毒性最大;3种镍钛形状记忆合金弓丝细胞毒性均在正常范围之内。结论 (1)人工唾液环境增加了镍钛形状记忆合金丝的细胞毒性,并随着浸泡时间的增加细胞毒性加大。(2)不同品牌、不同浸泡时间,正畸用镍钛弓丝细胞毒性不同。
Objective To evaluate the cytotoxicity of three kinds of nickel titanium shape memory alloy arch wires for orthodontics. Methods From November 2009 to March 2010, three brands of nickel titanium shape memory alloy arch wire (A: Masel brand American heat activated nickel-titanium tooth orthodontic wire ; B: Smart card made of heat-activated nickel-titanium tooth orthodontic wire; C: There are billion gold medal made of nickel titanium wire), making a number of pieces of each piece, the length of 0.5cm. They were divided into 3 parts in turn. One part was directly extracted after the treatment. The other two parts were immersed in artificial saliva. After 4 weeks and 8 weeks respectively, the extract was extracted. L-929 cell line was selected as the target of cytotoxicity. The growth of L-929 cells in the alloy wire was observed by inverted phase contrast microscopy. The MTT assay ), The absorbance (OD) value and the relative cell proliferation rate (RGR) of the cells at 24h and 48h after culture were obtained. The cytotoxicity of three brands of NiTi shape memory alloy arch wires was evaluated. Results After soaked in artificial saliva, the cytotoxicity of three brands of nickel titanium shape memory alloy arch wire increased with the prolongation of soaking time (P <0.05). Under the same immersion time, the cytotoxicity of A arch wire was the smallest, while C The archwire was the most cytotoxic. The cytotoxicity of all three Ni-Ti shape memory alloy arch wires was within the normal range. Conclusions (1) The artificial saliva environment increased the cytotoxicity of nickel-titanium shape memory alloy wire and increased the cytotoxicity with the increase of soaking time. (2) different brands, different soaking time, different doses of nickel titanium arch wire for orthodontic.