An ex vivo comparison of working length determination by 3 electronic apex locators

ObjectiveTo compare the accuracy of 3 different electronic apex locators (EALs) in establishing the working length in recently extracted teeth.Study designSixty teeth (100 canals) were soaked in an alginate model and electronically measured with 3 EALs (Dentaport ZX, Raypex 5, and Elements Diagnostic Unit and Apex Locator). The real working length was calculated as 1.0 mm short of the real length of the canal. The electronic measurements were taken following the manufacturers' orientations within ±0.05 mm and ±1.0 mm using a #15 K-file attached to the holder, after canal irrigation with 1% NaOCl. Data were analyzed with Friedman test and Wilcoxon signed rank test, at a significance level of 5%.ResultsWithin ±0.5 mm and ±1.0 mm, the accuracy was 39% and 90% (Dentaport ZX), 31% and 82% (Raypex 5), and 37% and 73% (Elements Diagnostic Unit and Apex Locator), respectively, with statistically significant differences between Elements Diagnostic Unit and Apex Locator and the other EALs.ConclusionNone of the EALs yielded an accuracy of 100%. Within the limitations of the present study. Elements Diagnostic Unit and Apex Locator proved to be less reliable than Dentaport ZX and Raypex 5 in the determination of the real working length.