Comparative Analysis of Accessory Mesial Canal Identification in Mandibular First Molars by Using Four Different Diagnostic Methods

IntroductionThe objective of the present in vitro study was to compare 4 diagnostic methods to identify accessory mesial canals (AMCs) in lower first molars.MethodsForty-four lower first molars were selected for assessment with cone-beam computed tomography (CBCT), digital radiography (DR), clinical inspection (CI), and dental operating microscope (DOM). Initially, axial images were obtained by using CBCT, and radiographs were taken in ortho, mesial, and distal angulations. The images were assessed by 2 independent groups of examiners, and all of the results obtained remained undisclosed until the end of the experiment. Subsequently, root canal access was prepared, and the mesial subpulpal groove was located by using sharp endodontic explorers. The roots were examined with DOM, and all identified canals were negotiated and instrumented by using a ProTaper Rotary System. The results were tabulated and statistically analyzed by nonparametric McNemar tests.ResultsTwelve AMCs (27.0%) were identified by CBCT, and 58.0% were instrumented. No AMCs were visualized in any DR examined. Fifteen potential AMCs (34%) were identified by CI, but only 47.0% were confirmed after instrumentation. Thirteen AMCs (30.0%) were identified by DOM, and 84.0% could be negotiated and instrumented.ConclusionsThere were statistically significant differences between the 4 types of assessments for AMC identification. There was good agreement between DOM and CBCT, whereas DR and CI were not as precise as either of the other 2 diagnostic methods.