A comparative evaluation of accuracy of three electronic apex locators using histological section as gold standard: An ex vivo study.

TLDR: All apex locators have been shown to produce acceptable level of accuracy which clearly indicates their reliability in determining the working lengths (WL) of teeth.

Abstract: Introduction: The aim of the present study was to comparatively evaluate the accuracy of iRoot, iPex II, and Propex pixi apex locator using histological sections as the gold standard. Materials and Methods: Thirty patients indicated for extraction of single-rooted permanent teeth with single canal system were selected. Working lengths (WLs) of teeth were determined using iRoot, iPex II, and Propex pixi. Teeth were then extracted, and the files were reintroduced to the anatomic apex to measure anatomic canal length (ACL) and fixed at the ACL using flowable composite. The apical 4 mm of the roots were longitudinally shaved away to visualize the canal under a stereomicroscope at ×24 magnification. Digital photographs were evaluated to measure the distance between the major diameter and minor diameter. Thus, the WL, that is, the minor diameter length (MDL) was ascertained. Results: Measurements of mean WLs within ±0.5 mm of minor diameter were 90% acceptable for iRoot, 86.66% for iPex II, and 80% for Propex pixi when compared with mean MDL as obtained from the histological sections. Conclusions: All apex locators have been shown to produce acceptable level of accuracy which clearly indicates their reliability in determining the WL.