Identification of the inferior alveolar canal using cone-beam computed tomography vs. panoramic radiography: a retrospective comparative study

BACKGROUND: This study aims at evaluating the visibility levels of the inferior alveolar canal (IAC) at different mandibular sites using panoramic (conventional & CBCT reformatted) and CBCT coronal views in a sample of a Palestinian population. METHODS: The panoramic (conventional [CP] & CBCT reformatted [CRP]) and CBCT coronal views (CCV) of 103 patients (206 records, right and left sides) were analyzed. The visibility of IAC at five sites extending from the first premolar to the third mandibular molar region was evaluated visually (and compared among the radiographic views) as clearly visible, probably visible, invisible/poorly visible, or not present at the examined site. On CCV, the maximum dimension of the IAC (MD), the vertical distance (VD) between the mandibular cortex and IAC, and the horizontal position (HP) of the IAC were noted. Statistical significance in the differences and relationships of the variables was tested using several statistical tests. RESULTS: There was a statistically significant relationship between the radiography modality (CP, CRP, CCV) and the visibility level of IAC (assessed in scores) at the five mandibular sites. When assessed on CP, CRP, and CCV, the IAC was clearly visible at all sites in 40.4%, 30.9%, and 39.6%, respectively, while being invisible/poorly visible in 27.5%, 38.9%, and 7.2% for the same views, respectively. The mean values of MD and VD were 3.61 mm and 8.48 mm, respectively. CONCLUSION: Different radiographic modalities would characterize the IAC’s structure in different qualities. Superior visibility levels were obtained interchangeably using CBCT cross-sectional views and conventional panorama at different sites compared to CBCT reformatted panorama. The IACs visibility was noted to improve at their distal aspects irrespective of the radiographic modality used. Gender —but not age— was a significant factor in the visibility level of IAC at only two mandibular sites.