Comparison of the Accuracy of CBCT Images and Apex Locator in Detection of External Root Resorption with Perforation

STATEMENT OF THE PROBLEM: Perforation within external root resorption (ERR) lesions dra-matically affects the prognosis of the involved roots. Failure to diagnose perforation under-mines treatment; therefore, early detection of these lesions is of great importance. The cone-beam computed tomography (CBCT) images and electronic apex locators (EAL) are reliably used to detect root perforations. PURPOSE: In this in vitro study, we compared the EAL findings with the results obtained by the CBCT images for the detection of perforations within ERR lesions. MATERIALS AND METHOD: This cross sectional study included 160 extracted anterior human teeth. The teeth were categorized into four groups including teeth with intact root, teeth with ERR, teeth with ERR and 0.5 mm perforation, and teeth with ERR with 1 mm perforation. The presence of perforations was compared by CBCT images and root EAL. RESULTS: The sensitivity of CBCT scans in detecting 0.5 mm and 1 mm root perforations was 100% and 97.5%, respectively, while the sensitivity of the EAL was 10% and 27.5% in de-tecting 0.5 mm and 1 mm root perforations, respectively( with the ±0.5mm range of error). For detecting intact and teeth with ERR, the specificity of CBCT scans was 100% and 95%, respectively, and for EAL, it was 100% for both. Poor agreement was found between the two techniques (kappa=-0.025). CONCLUSION: CBCT scans were more sensitive and specific than EAL scans for detecting perforations in non-obturated root canals in this study.