Determination of Working Length with Three Different Apex Locators

The purpose of this study was to test the accuracy three different apex locators. A total of 20 extracted single - rooted human teeth were used for this study. The teeth were embedded in an alginate (Alginate Plus, Henry Schein, Melville, NY, USA) model developed for electric working length determination with apex locators. Electronic length measurement was achieved with three different apex locators: Propex Apex Locator (Dentsply/Maillefer, Montigny le Bretonneux, Switzerland), Root ZX (Morita Europe, Dietzenbach, Germany), Elements Diagnostic Unit Apex Locator (Sybron Endo, Glendora, California, USA) using a size 15 K file (VDW GmbH, Munich, Germany). After that the working length was determined radiographically by placing a size 15 file to the root canal, then subtracting 1 mm from apex. Each root canal was prepared in the apical third and the distance between the instrument's tip to the apical foramen was analyzed under stereomicroscope. The results were subjected to statistical analysis with ANOVA using the SPSS 11.0 program. There were no significant differences between the different apex locators used and the radiographic control in determining working lengths. Electronic working length measurement with different apex locators used in this study proved the same results as the radiological control of canal length determination.