Morphology of Maxillary First and Second Molars Analyzed by Cone-Beam Computed Tomography in a Korean Population: Variations in the Number of Roots and Canals and the Incidence of Fusion

IntroductionThe aim of this study was to identify the root and canal morphology of the maxillary first and second molars in a Korean population by analyzing cone-beam computed tomography (CBCT) images.MethodsMaxillary first (n = 814) and second (n = 821) molars from Korean patients (n = 415) of Mongoloid origin were examined by using in vivo CBCT methods. The number and configuration of roots, the number of root canals, and the canal configuration according to Vertucci's classification were determined.ResultsSingle roots were found in 0.25% of the first molars and 4.63% of the second molars. The incidence of fused roots was 0.73% in the first molars and 10.71% in the second molars. In 802 3-rooted maxillary first molars, additional canals were found in 63.59% of the mesiobuccal (MB) roots and 1.25% of the distobuccal (DB) roots. In 660 3- or 4-rooted maxillary second molars, additional canals were found in 34.39% of the MB roots, 0.30% of the midbuccal roots, 0.30% of the DB roots, and 1.82% of the palatal roots. Bilateral symmetry of the MB roots was found in 88.10% of the first molars and 82.07% of the second molars.ConclusionsThe root and canal configuration of a Korean population showed different features from those of other populations. We report the incidence of rare morphologic variations, a single root and 3 buccal roots, that have not been described except for in case reports. CBCT scans can enhance the understanding of root canal anatomy, with the potential of improving the outcome of endodontic treatment.