An in vitro comparison of working length determination by two motor-driven electronic apex locators.

The aim of this study was to evaluate the in vitro working length determination of two different apex locator integrated endodontic motors during mechanical preparation. A total of 51 maxillary incisors were selected. The access cavities were prepared. The actual working lengths (AWL) were predetermined with a #15 stainless steel file. Specimens were then mounted in an alginate model. Working lengths recorded were VDW Gold (V1), Tri Auto ZX (T1) without using electronic motor and VDW Gold (V2), Tri Auto ZX (T2) by using apex locators in electronic motor operation mode. Data was analyzed by repeated measurements of ANOVA (α=0.01). No difference was found between V1, V2, T1 and T2 (P>0.01). However, statistical analysis found significant differences between AWL and other groups (P<0.01). As the values obtained in motor driven mode are equivalent to manual mode measurements, both devices can be safely used without disruption of working length.