Association between the Root Canal Configuration, Endodontic Treatment Technical Errors, and Periapical Hypodensities in Molar Teeth: A Cone-beam Computed Tomographic Study.

INTRODUCTION: This study aimed to evaluate the association between the root canal configuration (RCC), endodontic technical errors, and periapical hypodensities in molars using cone-beam computed tomographic (CBCT) images. METHODS: Two hundred twenty-one roots were assessed from 79 patients referred for CBCT examination because of symptomatology in endodontically treated molars. Two oral and maxillofacial radiologists classified the RCC of each dental root according to Vertucci's classification. Root canals were assessed for the presence of technical errors from endodontic treatment. The presence of periapical hypodensity for each dental root and the coronal sealing condition of each tooth were also recorded. RESULTS: For RCC type I, the most prevalent technical error was underfilling (17.4%). For types II and VIII, nonfilled canals were found in 54% and 100% of the cases, respectively. For type III, underfilling, nonhomogeneous filling, and nonfilled canals were equally frequent (33.3%), whereas for type IV underfilling and nonfilled canals had a prevalence of 42%. In general, there was a higher prevalence of apical hypodensities among roots with technical errors. It was also observed for type I, with an increase from 41.2%-62.9% when a technical error was present. CONCLUSIONS: The prevalence of different endodontic technical errors varies depending on the RCC for molars. A greater complexity of RCC is related to a higher occurrence of errors and a higher prevalence of periapical hypodensity.