Comparison of the accuracies of multi-frequency electronic apex locators in teeth with enlarged apical foramina: ex vivo

Objective: The aim of this study was to compare the accuracy of a newly developed multi-frequency electronic apex locator iPex II with three different multi-frequency electronic apex locators in teeth with different sizes of apical foramina. Materials and Method: Twenty-six extracted mandibular premolars were used in this study. The teeth were decoronated, and the root canals were coronally flared. Actual working length was determined by inserting a #15 K-file until the tip was visualized just within apical foramen. Actual working length was established 0.5 mm short of the distance between the rubber stopper and the file tip. Using Protaper F1, F2 and F3 files (Dentsply Maillefer), over-instrumentation 1 mm beyond the apical foramen was done. The teeth were embedded in teflon molds with alginate exposing the coronal 5 mm. Electronic working length measurements were done by using Raypex 5 (VDW), Raypex 6 (VDW), iPex (NSK Inc.) and iPex II (NSK Inc.) electronic apex locators. Differences between the electronic and actual working lengths were calculated. One-way analysis of variance (ANOVA) was used for the statistical analysis of the accuracies of the electronic apex locators (α=0.05). Results: Inter-group comparisons revealed that there was no statistically significant difference between the accuracies of the different electronic apex locators (p>0.05). Intra-group comparisons also revealed that there was no statistically significant difference between different apical foramen sizes (p>0.05). Conclusion: iPex II and the other electronic apex locators provided similar endodontic working length measurements in teeth with enlarged apical foramina. All electronic apex locators tested in this study were found clinically acceptable for working length determination.