title: Prevalence and features of distolingual roots in mandibular molars analyzed by cone-beam computed tomography.
abstract: OBJECTIVE
  This study evaluated the prevalence of distolingual roots in mandibular molars among Koreans, the root canal system associated with distolingual roots, and the concurrent appearance of a distolingual root in the mandibular first molar and a C-shaped canal in the mandibular second molar.
  
  
  METHODS
  Cone-beam computed tomographic images of 264 patients were screened and examined. Axial sections of 1056 mandibular molars were evaluated to determine the number of roots. The interorifice distances from the distolingual canal to the distobuccal canal were also estimated. Using an image analysis program, the root canal curvature was calculated. Pearson's chi-square test, the paired t-test, one-way analysis of variance, and post-hoc analysis were performed.
  
  
  RESULTS
  Distolingual roots were observed in 26.1% of the subjects. In cases where a distolingual root was observed in the mandibular molar, a significant difference was observed in the root canal curvature between the buccolingual and mesiodistal orientations. The maximum root canal curvature was most commonly observed in the mesiodistal orientation in the coronal portion, but in the apical portion, maximum root canal curvature was most often observed in the buccolingual orientation.
  
  
  CONCLUSIONS
  The canal curvature of distolingual roots was found to be very complex, with a different direction in each portion. No correlation was found between the presence of a distolingual root in the mandibular first molar and the presence of a C-shaped canal in the mandibular second molar.
authors.affiliation: Department of Conservative Dentistry, Wonkang University Daejeon Dental Hospital, Daejeon, Korea.
authors.forename: Mi-Ree
authors.initials: MR
authors.lastname: Choi
authors.affiliation: Department of Conservative Dentistry, Wonkang University Daejeon Dental Hospital, Daejeon, Korea.
authors.forename: Young-Mi
authors.initials: YM
authors.lastname: Moon
authors.affiliation: Department of Conservative Dentistry, Wonkang University Daejeon Dental Hospital, Daejeon, Korea.
authors.forename: Min-Seock
authors.initials: MS
authors.lastname: Seo
keywords: Cone-Beam Computed Tomography; Dental Pulp Cavity; Mandible; Molar