Imaging Sci Dent.  2014 Sep;44(3):229-236. 10.5624/isd.2014.44.3.229.

Assessment of bifid and trifid mandibular canals using cone-beam computed tomography

• Rashsuren
• Choi JW
• Han WJ
• Kim EK

• KMID: 1974487
• DOI: http://doi.org/10.5624/isd.2014.44.3.229

Abstract

PURPOSE
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.
MATERIALS AND 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 149.2degrees, and the mean inferior angle was 37.7degrees.
CONCLUSION
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.

Keyword

Mandibular Nerve; Cone-Beam Computed Tomography; Anatomic Variation

MeSH Terms

Anatomic Variation
Classification
Cone-Beam Computed Tomography*
Humans
Mandibular Nerve
Prevalence

Figure

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  Fig. 1 Cone-beam computed tomography (CBCT) image shows canal type 1 (retromolar canal type).

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  Fig. 2 CBCT image shows canal type 2 (dental canal type).

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  Fig. 3 CBCT images show canal type 3 (forward canal type A without confluence, B with confluence).

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  Fig. 4 CBCT image shows canal type 5A (trifid canal type: two accessory canals of the retromolar canal type).

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  Fig. 5 CBCT images show canal type 5B (trifid canal type: two accessory canals of one retromolar (A) and one dental canal (B) type).

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  Fig. 6 CBCT image shows canal type 5C (trifid canal type: two accessory canals of the dental canal type).

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  Fig. 7 CBCT image shows canal type 5D (trifid canal type: two accessory canals of one dental and one forward canal type).

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  Fig. 8 CBCT images show canal type 5E (trifid canal type: two accessory canals of the retromolar canal type (A-C) with two mandibular foramina (D)).

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