不同方法处理脱落托槽后其抗剪切强度对比研究

目的 观察正畸托槽脱落后再次黏结时托槽底板的不同处理方法对抗剪切强度的影响。方法 选择40颗离体人前磨牙,随机分成4组,每组10个样本,托槽均使用3M UNITEK transbond XT光敏树脂正畸黏结剂黏结。处理方法分别为更换新托槽组（简称更新组）;磨除底板残胶组（简称磨除组）;托槽底板喷砂处理组（简称喷砂组）;氯仿溶液浸泡溶解托槽底板上的黏结剂组（简称氯仿浸润组）。各样本均采用万能测试机进行剪切强度试验,记录每组抗剪切强度数值的变化并观察ARI指数（牙面残留黏结剂指数）。结果 磨除组、喷砂组抗剪切强度增强,氯仿浸泡组抗剪切强度则减弱,三者间均有统计学差异。结论 黏结脱落托槽时可采用磨除法或喷砂法对脱落托槽底板进行处理。

Comparison on shear bond strength of reused orthodontic brackets with different treatment methods

Objective To compare shear bond strength（SBS） of reused orthodontic brackets with different treatment methods. Methods 40 extracted premolars were divided into four groups. Brackets were debonded and the base mesh of the brackets were dealt with with four different treatments. In group I , new brackets were reused . In group Ⅱ , residual adhesives were removed with a sword-edge stone, then the brackets were reused. In group Ⅲ, the brackets were reused after sandblasting with 90-microm particle aluminum oxide. In groupIV, the brackets were soaked into solution CHC13 for about 2 or 3 weeks, then they were reused . Shear test was performed, at the same time the SBS and adhesive remnant indexes （ARI） were compared among four groups. Results The SBS was significantly higher in group Ⅱ and group Ⅲ, however, the SBS was significantly lower in group Ⅳ. The results showed significant differences （ P 〈 0.05 ）. Conclusion The data suggest that the optimal procedure is to use a sword-edge stone or a sandblasting device to treat the base mesh of brackets to get the better shear bond strength.