关键词: 根尖定位仪 , 根管治疗, 根管充填质量 , 根管工作长度

Abstract: Objective To evaluate the quality of root canal obturation and the effect factor on accuracy of electronic apex locator for determining root canal working length. Methods Totally 265 root canals needing root canal therapy in 136 teeth were chosen，and were randomly divided into two groups：experimental group and control group. The working length was measured by electronic apex locator in experiment group and was measured manually by hand and X-ray in control group.Canal preparation was done by step-back technique manually and canal obturation was done with lateral compaction，then an X-ray film was taken in order to judge its quality. Results The rates of flush filled in experimental geoup was 86.52%， and The rate of flush filled in control group was 76.61%.There was statistical difference between the two groups（P < 0.05）.Conclusion Electronic apex locator can measure root canal length accurately and improve the quality of canal obturation with lateral compaction.

Key words: apex locator, root canal therapy, canal obturation quality , root canal working length