Imaging Sci Dent.  2014 Mar;44(1):53-60. 10.5624/isd.2014.44.1.53.

The incidence and configuration of the bifid mandibular canal in Koreans by using cone-beam computed tomography

• Kang JH
• Lee KS
• Oh MG
• Choi HY
• Lee SR
• Oh SH
• Choi YJ
• Kim GT
• Choi YS
• Hwang EH

• KMID: 1974474
• DOI: http://doi.org/10.5624/isd.2014.44.1.53

Abstract

PURPOSE
This study was performed to investigate the incidence and configuration of the bifid mandibular canal in a Korean population by using cone-beam computed tomography (CBCT) imaging.
MATERIALS AND METHODS
CBCT images of 1933 patients (884 male and 1049 female) were evaluated using PSR-9000N and Alphard-Vega 3030 Dental CT units (Asahi Roentgen Ind. Co., Ltd, Kyoto, Japan). Image analysis was performed by using OnDemand3D software (CyberMed Inc., Seoul, Korea). The bifid mandibular canal was identified and classified into four types, namely, the forward canal, buccolingual canal, dental canal, and retromolar canal. Statistical analysis was performed by using the chi-squared test and one-way analysis of variance (ANOVA).
RESULTS
Bifid mandibular canals were observed in 198 (10.2%) of 1933 patients. The most frequently observed type of bifid mandibular canal was the retromolar canal (n=104, rate: 52.5%) without any significant difference among the incidence of each age and gender. The mean diameter of the accessory canal was 1.27 mm (range: 0.27-3.29 mm) without any significant difference among the mean diameter of each type of the bifid mandibular canal. The mean length of the bifid mandibular canals was 14.97mm(range: 2.17-38.8 mm) with only a significant difference between the dental canal and the other types.
CONCLUSION
The bifid mandibular canal is not uncommon in Koreans and has a prevalence of 10.2% as indicated in the present study. It is suggested that a CBCT examination be recommended for detecting a bifid canal.

Keyword

Cone-Beam Computed Tomography; Mandibular Nerve; Abnormalities; Radiography

MeSH Terms

Cone-Beam Computed Tomography*
Humans
Incidence*
Male
Mandibular Nerve
Prevalence
Radiography
Seoul

Figure

• 

  Fig. 1 Reconstruction of the images of longitudinal sections. A. The reference line is set at the mandibular foramen in the axial image, then rotated horizontally. B. The reference line is moved bucco-lingually and postero-anteriorly. C. A sagittal image shows clear image of the bifid mandibular canal (white arrowheads).

• 

  Fig. 2 A diagram of configuration of the bifid mandibular canal is classified into four types as follows by Naitoh et al7 1) The forward canal included with confluence (A) or without confluence (B). 2) The bucco-lingual canal from the buccal or lingual wall (C and D). 3) The dental canal reached to the root apex (E). 4) The retromolar canal branched to the retromolar foramen (F).

• 

  Fig. 3 CBCT images of each type of the bifid mandibular canal. A. The forward canal without confluence courses to the second molar region. B. The forward canal with confluence courses anteriorly and then joined up with the main canal. C and D. The dental canal courses forward and reaches the root apex of the third molar. E. The buccal canal branched from the buccal wall of the main canal. F. The lingual canal branched from the lingual wall of the main canal. G. The retromolar canal courses upward and reaches the retromolar area. H. The retromolar foramen (white arrowhead) on the bone surface of the retromolar region.

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