目的 :研究不同弯曲度的根管对Raypex5、PropexⅡ和Rider3种电子根尖定位仪(electronic apex locator,EAL)测量准确性的影响。方法:采用藻酸盐和离体牙构建EAL体外模型,使用Raypex5、PropexⅡ和Rider3种EAL,对123个根管进行根管长度测量,记录测量工作长度值(experimental measurements,EM)及与理论工作长度值(ideal measurements,IAM)之间的差值(IF值)。采用SPSS11.5软件包对数据进行统计学分析。结果:以IAM值±0.5 mm为衡量标准,计算EAL测量直根管、中度和重度弯曲根管的准确率,Raypex5分别为84.6%、81.6%、87.5%,PropexⅡ分别为76.9%、89.8%、91.7%,Rider分别为92.3%、89.8%、87.5%。经检验,各组间IF值无差异显著。结论:根管的弯曲度对根尖定位仪的测量准确性无显著影响,但根管弯曲度不同,不同EAL测量的准确率略有差异。 Objective: To study the influence of different tortuous root canals on the measurement accuracy of Raypex  5, Propex   and Rider  3 kinds of electronic apex locators (EALs). Methods: The EAL in vitro model was established by using alginate and isolated teeth. The length of root canal was measured in 123 root canals using Raypex  5, Propex   and Rider  EAL. The experimental measurements were recorded ) And the difference (IF value) from the ideal measurements (IAM). SPSS11.5 software package for statistical analysis of the data. Results: The accuracy of EAL was 84.6%, 81.6%, 87.5%, PropexⅡ were 76.9%, respectively. The accuracy of EAL in measuring root canal, moderate and severe curved root canal was calculated by ± 0.5 mm IAM value. , 89.8% and 91.7% respectively, while Rider was 92.3%, 89.8% and 87.5% respectively. After testing, no significant difference between the IF values ​​of the various groups. Conclusions: The curvature of root canal has no significant effect on the accuracy of apical localization, but the curvature of root canal is different. The accuracy of different EAL measurements is slightly different.