Endodontic Working Length Measurement with Preexisting Cone-Beam Computed Tomography Scanning: A Prospective, Controlled Clinical Study

Introduction: The determination of root canal length is a significant outcome predictor for endodontic treatments. The aim of this prospective, controlled clinical study was to analyze endodontic working length measurements in preexisting cone-beam computed tomography (CBCT) scans and to compare them with clinical root canal length determination by using an electronic apex locator (EAL). Methods: All included patients had received a CBCT scan independent of the present study and needed root canal treatment of at least 1 anterior tooth visible in the field of view. Clinically, the root canal length was measured with an EAL by an endodontist. This measurement was compared with the root canal length as measured on vestibulooral and mesiodistal CBCT sections by an examiner not involved in the endodontic treatment. The CBCT measurements were repeated once for analysis of intrarater reliability. Results: Forty anterior teeth in 30 patients (13 women and 17 men; average age, 44 years; range, 18-80 years) were included in this investigation. The Pearson correlation coefficient (r) comparing the root canal length measurements by using CBCT and EAL was 0.97. In addition, high intrarater reliability for the CBCT measurements was found (r = 0.99). Conclusions: This prospective, controlled clinical study showed that limited CBCT scans can be used for endodontic working length measurements. Future studies are needed to evaluate whether preexisting CBCT scans could replace initial periapical radiographs and working length periapical radiographs. (J Endod 2012;38:884-888)