Accuracies of seven different apex locators under various conditions

The purpose of this study was to evaluate the accuracies of 7 different frequency-dependent electronic apex locators (EALs) on using different irrigants in the root canal.

Root canal lengths were measured with 7 different EALs in 40 extracted human teeth embedded in an alginate model after canal preparation and compared with the actual canal length measurements taken before embedding the teeth in alginate. The EALs used were Apex Finder 7005, Apit, Bingo-1020, e-Magic Finder, ProPex, Root ZX, and SmarPex. Measurements were taken with the canal dry, and saturated sequentially with 5.25% NaOCl, saline, 0.1% chlorhexidine, and 15% EDTA. Data were analyzed with 1-way ANOVA and Tukey's studentized range test.

There were some differences in accuracies among EALs; however, some of the differences were not statistically significant. All EALs were less accurate when the apical foramen size was larger.

Within the limitations of the present study, most of the EALs tested can be considered reliable in the presence of various root canal irrigants and varying sizes of the apical foramen.