下颌第二恒磨牙C形根管的离体实验研究

目的：寻找一种预备C形根管的有效器械，提高下颌第二恒磨牙的治愈率。方法：选用80颗具有C形根管的下颌第二恒磨牙，选择四种器械进行根管预备，第一组用不锈钢K锉，第二组用不锈钢K锉和手用镍钛器械，第三组用机用镍钛器械，第四组用超声根管治疗仪，预备中均用3％双氧水和生理盐水交替反复冲洗根管，预备后用Vitapex糊剂和牙胶尖冷侧压方法充填根管，观察根充后X线片和根尖微渗漏情况，评价充填效果。结果：四种器械根充后微渗漏有明显差异（P〈0．05）。结论：不锈钢K锉和手用镍钛器械联合应用及超声根管治疗仪为预备C形根管的有效器械。

Study of C-Shaped Root Canals in Mandibular Second Molars in Vitro

Objective： The aim of this study was to search a kind of effective instrument for preparation the C-shaped root canals and improve the healing rate of mandibular second molars. Methods： 80 mandibular second molars were extracted and randomly divided into 4 experimental groups. Group 1 were prepared by SS-K file; group 2 were prepared by SS-K file combined PF, group 3 were prepared by NT, group 4 were prepared by ultrasonic root canal instrumentation. All root canals were filled by warm vertical condensation using Vitapex paste and gutta percha point. Effect of filling was evaluated by apical microleakage and digital X ray shows. Results： Among the different instrumentations,the group 2 and group4 have the least microleakage. But there were no significant difference between the group 2 and group 4 （P〉0.05）. Conclusion： SS-k file combined PF or ultrasonic root canal instrumentation is the effective instrument for preparing the C-shape root canals.