Accuracy of two electronic apex locators in mandibular mesial canals and the influence of root canal anatomy: a micro-CT-based study

OpenAlex İngilizce

BACKGROUND: This study aimed to compare working length measurements obtained using two different electronic apex locators (EALs), Propex Pixi and Woodpecker, at two distinct measurement points, and to evaluate how anatomical complexities affect their accuracy. The working length data from these EAL measurements were compared with gold-standard values determined by micro-computed tomography (micro-CT). METHODS: Mesial roots of 46 mandibular molars were included. Actual canal lengths (RCL) were determined under an operating microscope. The real working length (RWL) was calculated by subtracting the distance between the apical foramen and apical constriction, as determined by micro-CT, from the RCL. All teeth were embedded in an alginate model. Measurements were taken at two points: at the '0.5' point (recorded as electronic working length 1, EWL1) and at the '0.0' point, from which 0.5 mm was subtracted clinically to obtain electronic working length 2 (EWL2). All specimens were scanned with micro-CT to assess the location, diameter, and morphology of the apical constriction and apical foramen, the distance between them, and the presence of accessory canals. Categorical data were analyzed with Chi-Square tests; measurement values with repeated measures ANOVA and Tukey's post-hoc tests. The significance level was set at p ≤ 0.05. RESULTS: Both EAL devices measured significantly longer working lengths compared to the actual values (p < 0.0001). Significant differences were found among measurement methods, with EWL2 being closer to RWL than EWL1 (p < 0.05). Both devices showed higher precision at EWL2, while AF location and accessory canals had no significant effect. An AF-AC distance greater than 0.5 mm increased errors at EWL1 with Propex Pixi (p = 0.005). CONCLUSION: Both devices tended to overestimate the working length, and subtracting 0.5 mm from the '0.0' reading improved measurement accuracy. Apical foramen location and accessory canals did not significantly affect results.