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. 2011 Oct;8(4):203-10.
doi: 10.4103/1735-3327.86041.

Comparison between cone beam computed tomography and panoramic radiography in the assessment of the relationship between the mandibular canal and impacted class C mandibular third molars

Zahra Dalili  1 , Porousha Mahjoub, Ali Khalighi Sigaroudi
Affiliations

Comparison between cone beam computed tomography and panoramic radiography in the assessment of the relationship between the mandibular canal and impacted class C mandibular third molars

Zahra Dalili et al. Dent Res J (Isfahan). 2011 Oct.

Abstract

Background: Preoperative radiographic evaluation of impacted third molars is essential to determine the proximity to the mandibular canal to minimize the risk of nerve injury. Our study aim was to evaluate the relationship between the mandibular canal and impacted mandibular third molars using cone beam computed tomography (CBCT) and to compare findings therein with panoramic radiographic signs.

Methods: CBCT images were taken from 29 patients having 43 Class C impacted mandibular third molars whose panoramic radiographs showed a close relationship between the mandibular canal and mandibular third molars. We evaluated their tomographs to determine the course of the canal, its proximity to the root, any narrowing of the canal, the presence of root grooving or hooks and the proximity of the root to the cortex. A Chi-square test was used for data analysis.

Results: The lingual course of the canal was the most frequently detected course in all panoramic findings. Contact of the tooth with the canal was observed in all cases in which panoramic signs of deviation of the canal and darkening of the roots were found. The frequency of observing the narrowing of the canal in CBCT as compared to seeing the presence or the absence of canal narrowing in panoramic radiographs was significantly different (P=0.01).

Conclusion: CBCT provides more precise diagnostic information to determine the relationship of impacted third molars to the canal. Deviation of the canal and darkening of the roots in panoramic view can be highly valuable to predict the risk of nerve injury.

Keywords: Cone beam computed tomography; mandibular canal; panoramic radiography; third molar.

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Conflict of interest statement

Conflict of Interest: None declared.

Figures

Figure 1a
Figure 1a
Panoramic view of a left mandibular Class C impacted third molar having curved roots and odontoma adjacent to the coronal portion
Figure 1b-c
Figure 1b-c
Axial cut and reconstructed panoramic view showing colorization of the mandibular canal (colorization is only in panoramic view)
Figure 1d-e
Figure 1d-e
Cross-sectional and 3-D images reveal a lingual position of the canal having close proximity to the root surface
See this image and copyright information in PMC

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