title: Assessment of bifid and trifid mandibular canals using cone-beam computed tomography.
abstract: OBJECTIVE
  To investigate the prevalence of bifid and trifid mandibular canals using cone-beam computed tomography (CBCT) images, and to measure their length, diameter, and angle.
  
  
  METHODS
  CBCT images of 500 patients, involving 755 hemi-mandibles, were used for this study. The presence and type of bifid mandibular canal was evaluated according to a modified classification of Naitoh et al. Prevalence rates were determined according to age group, gender, and type. Further, their diameter, length, and angles were measured using PACSPLUS Viewer and ImageJ 1.46r. Statistical analysis with chi-squared and analysis of variance (ANOVA) tests was performed.
  
  
  RESULTS
  Bifid and trifid mandibular canals were found in 22.6% of the 500 patients and 16.2% of the 755 sides. There was no significant difference between genders and among age groups. The retromolar canal type accounted for 71.3% of the identified canals; the dental canal type, 18.8%; the forward canal type, 4.1%; and the trifid canal type, 5.8%. Interestingly, seven cases of the trifid canal type, which has been rarely reported, were observed. The mean diameter of the bifid and trifid mandibular canals was 2.2 mm and that of the main mandibular canal was 4.3 mm. Their mean length was 16.9 mm; the mean superior angle was 149.2°, and the mean inferior angle was 37.7°.
  
  
  CONCLUSIONS
  Bifid and trifid mandibular canals in the Korean population were observed at a relatively high rate through a CBCT evaluation, and the most common type was the retromolar canal. CBCT is suggested for a detailed evaluation of bifid and trifid mandibular canals before mandibular surgery.
authors.affiliation: Department of Oral and Maxillofacial Radiology, School of Dentistry, Mongolian National University Medical Science, Ulaanbaatar, Mongolia.
authors.forename: Oyuntugs
authors.initials: O
authors.lastname: Rashsuren
authors.affiliation: Department of Oral and Maxillofacial Radiology, Dankook University College of Dentistry, Cheonan, Korea.
authors.forename: Jin-Woo
authors.initials: JW
authors.lastname: Choi
authors.affiliation: Department of Oral and Maxillofacial Radiology, Dankook University College of Dentistry, Cheonan, Korea.
authors.forename: Won-Jeong
authors.initials: WJ
authors.lastname: Han
authors.affiliation: Department of Oral and Maxillofacial Radiology, Dankook University College of Dentistry, Cheonan, Korea.
authors.forename: Eun-Kyung
authors.initials: EK
authors.lastname: Kim
keywords: Anatomic Variation; Cone-Beam Computed Tomography; Mandibular Nerve