Imaging Sci Dent.  2014 Dec;44(4):273-278. 10.5624/isd.2014.44.4.273.

Radiographic evaluation of the course and visibility of the mandibular canal

• Jung YH
• Cho BH

• KMID: 1974495
• DOI: http://doi.org/10.5624/isd.2014.44.4.273

Abstract

PURPOSE
This study was performed to investigate the course of the mandibular canal on panoramic radiography and the visibility of this canal on both panoramic radiography and cone-beam computed tomography (CBCT).
MATERIALS AND METHODS
The study consisted of panoramic radiographs and CBCT images from 262 patients. The course of the mandibular canal, as seen in panoramic radiographs, was classified into four types: linear, elliptical, spoon-shaped, and turning curves. The visibility of this canal from the first to the third molar region was evaluated by visually determining whether the mandibular canal was clearly visible, probably visible, or invisible. The visibihlity of the canal on panoramic radiographs was compared with that on CBCT images.
RESULTS
Elliptical curves were most frequently observed along the course of the mandibular canal. The percentage of clearly visible mandibular canals was the highest among the spoon-shaped curves and the lowest among the linear curves. On panoramic radiographs, invisible mandibular canals were found in 22.7% of the examined sites in the first molar region, 11.8% in the second molar region, and 1.3% in the third molar region. On CBCT cross-sectional images, the mandibular canal was invisible in 8.2% of the examined sites in the first molar region, 5.7% in the second molar region, and 0.2% in the third molar region.
CONCLUSION
The visibility of this canal was lower in the first molar region than in the third molar region. The mandibular canal presented better visibility on CBCT images than on panoramic radiographs.

Keyword

Cone-Beam Computed Tomography; Radiography, Panoramic; Mandible; Nerve, Inferior Alveolar

MeSH Terms

Cone-Beam Computed Tomography
Humans
Mandible
Mandibular Nerve
Molar
Molar, Third
Radiography, Panoramic

Figure

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  Fig. 1 Classifications of the course of the mandibular canal on panoramic radiographs: A. Linear curve, the canal curve is approximately a straight line; B. Elliptic curve, the curve is approximately symmetrical; C. Spoon-shaped curve, the canal has an approximate spoon shape that is similar to an asymmetric elliptic arc; and D. Turning curve, the course is unsmooth and has a turning point.

• 

  Fig. 2 Classification of the visibility of the mandibular canal on cross-sectional cone-beam computed tomography images: A. Clearly visible, the whole circumference of the bony wall is clearly visible; B. Probably visible, the canal wall is partly visible; and C. Invisible, the canal is not identifiable with certainty.

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