四种正畸矫治弓丝的细胞毒性研究

目的评价四种临床常用正畸矫治弓丝经人工唾液浸泡腐蚀后的细胞毒性。方法选择正畸常用两种超弹性镍钛矫治弓丝和两种不锈钢矫治弓丝(A组:速航国产超弹性镍钛矫治弓丝;B组:Smart国产超弹性镍钛矫治弓丝;C组:PLASDENT国产不锈钢矫治弓丝;D组:ORMAER国产不锈钢矫治弓丝),在弱酸性(pH=6.0)人工唾液中浸泡4周后,取出试件制备浓度为20%、50%、100%的浸提液。使用不同浓度浸提液培养L-929细胞24 h、48 h后,分别使用SEM及MTT实验,初步评价四种矫治弓丝的细胞毒性。结果相同培养时间下,随浸提液浓度的增加,细胞相对增殖率减小,细胞毒性相对增加(P<0.05);相同浸提液浓度下,随培养时间的延长,细胞相对增殖率减小,细胞毒性相对增加(P<0.05)。100%浸提液浓度培养24 h后,四组浸提液均未对L-929细胞产生细胞毒性,培养48 h后,A、B、D三组浸提液对L-929细胞产生了轻微的细胞毒性,细胞毒性为1级,C组浸提液未对L-929细胞产生细胞毒性。结论经唾液浸泡腐蚀后的矫治弓丝,可能会引起轻微的细胞毒性,其结果应引起临床医生的重视。

Study of cytotoxicity of four kinds of orthodontic arch wires

Objective To evaluate the cytotoxicity of four kinds of orthodontic alloy wires after corrosion in artificial saliva.MethodsChoose two kinds of superelastic nickel-titanium arch wires and two kinds of stainless steel arch wires and immerse them separately in acidic artificial saliva （pH=6.0） for four weeks, then take them out to make extract liquid of 20%, 50%,100% concentration. Cultivate L-929 cells in the extract and observe the growth of the cells after 24 h and 48 h. Finally through the MTT assay and the cell relative growth rate（RGR）, value the cytotoxicity of the four kinds of arch wires.ResultsWith the cultivation time extending, the cell RGR decreased, the cytotoxicity relatively increased （P〈0.05）; With the extract concentration increasing, the cell RGR decreased, the cytotoxicity relatively increased（P〈0.05）. In extract of 100% concentration, after 24 h cultivating, the four kinds of extract did＇t generate cytotoxicity to L-929 cells; after 48 h cultivating, A, B, D groups generate slight cytotoxicity to L-929 cells, for 1 class of cytotoxicity, while C group didn′t generate cytotoxicity to L-929 cells.ConclusionThe arch wires after corrosion might generate slight cytotoxicity, that should cause the attention of clinicians.