Imaging Sci Dent.  2013 Jun;43(2):105-109. 10.5624/isd.2013.43.2.105.

Comparison of panoramic radiography with cone beam CT in predicting the relationship of the mandibular third molar roots to the alveolar canal

• Shahidi S
• Zamiri B
• Bronoosh P

• KMID: 1974437
• DOI: http://doi.org/10.5624/isd.2013.43.2.105

Abstract

PURPOSE
Preoperative radiographic assessment of the mandibular third molars is essential to prevent inferior alveolar nerve damage during extraction. The purpose of this study was to assess the reliability of panoramic signs of association between the roots of teeth and the canal, and to compare the panoramic signs with cone beam computed tomography (CBCT) findings.
MATERIALS AND METHODS
CBCT images of 132 impacted mandibular third molars were evaluated to determine the association of the root to the canal. The CBCT findings were compared with the corresponding panoramic images. Logistic regression analysis was used to define the diagnostic criteria of the panoramic images.
RESULTS
Among the panoramic signs, loss of the cortical line was the most frequent radiographic sign predicting association (sensitivity: 79.31). Contact of the tooth with the canal was observed in all cases in which the loss of cortical line of the canal or darkening of the roots was found on the panoramic radiographs.
CONCLUSION
Darkening of the roots and loss of the cortical line on panoramic radiographs might be highly suggestive of the risk of nerve injury.

Keyword

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

MeSH Terms

Cone-Beam Computed Tomography
Logistic Models
Mandibular Nerve
Molar, Third
Radiography, Panoramic
Tooth

Figure

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  Fig. 1 A. Cropped panoramic radiograph shows the interruption of the superior wall of the mandibular canal due to the root of the left impacted mandibular third molar. B. CBCT image of same tooth demonstrates the direct association of the root and canal.

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  Fig. 2 A. Cropped panoramic radiograph shows the darkening of both roots of the right impacted mandibular third molar. B. CBCT images of the same tooth show direct contact between the root and canal.

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