17% EDTA与脉冲Nd：YAG激光去除根管壁玷污层疗效的电镜研究

目的对17%EDTA与脉冲Nd：YAG激光对根管壁玷污层清除效果进行分析与比较。方法选取30颗新鲜单根成人离体牙,根管机械预备后随机分为三组,每组10例,分别给予5.25%NaClO冲洗（对照组）、17%EDTA＋5.25%NaClO冲洗以及5.25%NaClO冲洗＋Nd：YAG激光照射处理后,电镜下观察根管侧壁玷污层去除情况。利用计算机图像分析软件计算开放牙本质小管口面积/牙本质面积比。统计学方法采用单因素方差分析,α=0.05。结果EDTA冲洗及Nd：YAG激光照射后均可使根管侧壁玷污层明显减少,但EDTA冲洗对牙本质小管口开放作用明显优于Nd：YAG激光照射组及对照组（P〈0.01）。结论17%EDTA对根管壁玷污层的清除效果优于脉冲Nd：YAG激光,适合于临床广泛应用。

SEM evaluation of smear layer clearance by EDTA and pulsed Nd:YAG laser

Objective To evaluate the removal effects of 17%EDTA and Nd：YAG laser on smear layer in vitro. Methods Thirty extracted permanent teeth with single straight root canals were included. The root canals were instrumented and were randomly divided into three groups. Group A was irrigated with 5.25% NaCIO; group B was irrigated with 17% EDTA, followed by 5.25% NaCIO; and group C was irrigated with 5.25% NaCIO, followed by Nd： YAG laser. The teeth were then prepared for SEM examination and the open tubules/total dentinal surface ratio was measured by using computerized image analysis software. Results The removal effects of 17% EDTA and Nd：YAG laser on smear layer were obvious. However, specimens irrigated with 17% EDTA demonstrated significantly more effective for open dentinal tubules than those for the other two groups （ P 〈 0.01 ）. Conclusion 17% EDTA was more effective than Nd：YAG laser on removing the smear layer.