Objectives: Detailed information of complex anatomical configuration of mesiobuccal (MB) root is essential for successful endodontic treatment in maxillary first molars. The aims of this study were to investigate the configuration types present in multiple-canalled MB roots of maxillary first molars using micro-computed tomography (μCT) and to evaluate whether further modification to current configuration classifications are needed for in-depth morphology study of MB root canal system.
Materials and methods: One hundred and fifty-four extracted human maxillary first molar MB roots were scanned by μCT (Skyscan) and their canals were reconstructed by 3D modeling software. Root canal configurations were categorized according to the classifications proposed by Weine and Vertucci. Canal configurations that did not fit into both classifications were categorized as non-classifiable.
Results: One hundred and thirteen (73.4 %) MB roots had multiple canals. The most predominant canal configuration was Weine type III (two orifices and two foramens). Thirty-three (29.2 %) and 20 (17.7 %) MB roots had non-classifiable configuration types that could not be classified by the Weine and Vertucci classification, respectively. Three configurations (types 1-3, 2-3-2-3-2, and 2-3-4-3-2) were first reported in maxillary first molar MB roots.
Conclusions: The present μCT study provided an in-depth analysis of canal configurations of the MB roots of maxillary first molar and suggests that additional modification of current configuration classifications may be needed to more accurately reflect the morphology configurations of MB roots.
Clinical relevance: Clinicians should consider the complex canal configurations of the maxillary first molar MB roots during surgical or nonsurgical endodontic procedures.