桩道制备后根管冠方渗漏的体外实验

目的 本实验拟用染色实验，比较根管内牙胶余留全长、3、5、7mm两周后的冠方渗漏，为探讨桩道制备后根管充填的封闭性能做一参考：方法取86颗单根离体牙，按照牙胶余留量及暂时充填材料的不同分为8组，常规根管充填并桩道预备后，用次甲基蓝进行由冠方向根方的渗漏，2周后测量渗漏深度，统计结果并加以分析。结果各组均有渗漏，其中以牙胶封闭且根管内牙胶余留3mm组的渗漏距离最大．以氧化锌水门汀封闭且未去除根管内牙胶组的渗漏距离最小。但是8组的渗漏深度差异无统计学意义（P=0．1033）。结论桩道制备会增加根管充填的冠方渗漏，而氧化锌水门汀的封闭性能较牙胶强，但在两周时间内渗漏对根尖部封闭性能影响不大．

In vitro study of coronal leakage after post space preparation

Objective To compare the coronal leakage of different length of gutta-percha reumants （full length, 3, 5, 7mm） two weeks after post preparation, using a dye penetration method. Methods Eighty-six single-root extracted teeth were divided into eight groups according to the length of gutta-percha remnant and the materials of temporary coronal filling. Teeth were instrumented and obturated in a routine way. Post space was prepared to different depths. Specimens were then submerged in 2% methylene blue dye for two weeks. Dye leakage was measured and statistical analysis was performed. Results Dye leakage was observed in all groups. The highest leakage was recorded in group A4 with 3mm-long gutta-percha reumant and coronal sealing of gntta-percha, whereas the lowest leakage was recorded in group B1 with full length of gutta-percha and coronal sealing of ZOE cement. However, there was no statistically significant difference among eight groups （P-0.1033）. Conclusions The post space preparation would decrease the sealing ability of root canal filling. Gutta-percha showed poorer sealing ability than ZOE cement as coronal temporary filling materials. However, there was no significant difference between them in 2 weeks.