Hero642镍钛机动器械根管再治疗清理效果的扫描电镜观察

Cleaning efficacy of Hero 642 rotary NiTi instruments in endodontic retreatment: a scanning electron microscopic study

目的:评价Hero642镍钛机动根管预备器械用于根管再治疗的清理效果。方法:选取临床拔除的36个单根管前牙,随机分为A、B、C3组,用改良式逐步后退法进行根管预备,牙胶尖与碧兰糊剂侧方加压充填根管。30d后,分别采用以下器械与方法去除根管内充填物:A组为不锈钢手用H锉与氯仿;B组为Hero642镍钛机动器械与氯仿;C组为Hero642镍钛机动器械与电热式牙胶加热器。记录操作时间。纵剖样本,扫描电镜下观察根尖1/3、根中1/3、冠1/3的碎屑与玷污层。结果:在根管中段和尖段,C组根管壁的碎屑和玷污层较A、B组少,A组与C组间存在统计学差异(P<0.05);在冠1/3处,3种方法对根管的清理效果无统计学差异(P>0.05)。B组与C组的操作时间明显少于A组,具有统计学差异(P<0.01)。结论:使用Hero642镍钛机动根管预备器械结合电热式牙胶加热器能有效去除根管内牙胶充填物并节省操作时间,值得在临床推广。

AIM ：To evaluate the cleaning efficacy of Hero 642 NiTi instruments in endodontic retreatment. METHODS. Thirty- six extracted single- root anterior teeth were instrumented by modified step -back flare technique and obturated with laterally condensed gutta - pereha and sealer. Removal of gutta - percha was performed by the following devices and methods： stainless steel H file with chloroform, Hero 642 with chloroform and Hero 642 with heat carrier. The time for retreatment was recorded. The roots were split longitudinally into two parts. The scanning electron microscope was used to evaluate the amount of residual debris and smear layer on the apical, middle, coronal parts of root canal walls. RESULTS：At the apical and mid -root levels, less debris and smear layer were observed in group C than in groups A and B, with a significant difference detected between groups A and C（ P 〈 0.05 ）. There was no significant difference among the three groups at the coronal level （P 〉 0.05 ）. The time for retreatment in group B and group C was less than that in group A. The difference was statistically significant （ P 〈 0.05 ）. CONCLUSION： Use of Hero 642 with heat carrier is proved to be an efficient method for endodontic retreatment.