Abstract
Abstract : Purpose : The aim of this study was to assess the root anatomy and canal morphology of mandibular third molars as well as these molars’ positional relationships with the mandibular canal in a Japanese population using dental cone-beam computed tomography (CBCT).
Materials and Methods : We analyzed the CBCT images of 155 mandibular third molars from 105 patients. The following parameters were observed on CBCT : (1) number of roots and root canals ; (2) Vertucci classifications of the root canal configurations ; (3) frequency of C-shaped roots ; (4) classifications of axial canal images of C-shaped canals ; and (5) the positional relationship between mandibular third molars and the mandibular canals.
Results : Most mandibular third molars had two roots with two root canals (62.6%), in which most of the mesial root canals (90.7%) of the two-rooted molars were Type I. The C-shaped root prevalence was 14.2%, with a bilateral incidence of 2.0%. Additionally, most canals with continuous C-shapes appeared to fuse into one or divide into two canals toward the canal terminus. Regarding the positional relationship between the mandibular third molar and mandibular canal in the non-bone-mediated type, the frequency of the inferior type was 21.3% and that of the lingual type was 7.1% ; mandibular canal flattening was often seen in the former.
Conclusion : This study provided detailed information regarding the root anatomy and root canal morphology of mandibular third molars and these molars’ positional relationships with the mandibular canal in a Japanese population.
