Visibility of Inferior Alveolar Canal Borders Using Panoramic Radiography and Cross-sectional CBCT Images

Background: Clinical identification of the inferior alveolar canal (IAC) is crucial before performing surgical interventions such as mandibular third molar extraction or jaw fixation to preserve the integrity of the IAC. This study evaluated the visibility of IAC borders using panoramic radiography (conventional and CBCT reformatted) and cross-sectional CBCT images. Methods: The conventional panoramic (CP) and CBCT images of 328 patients were evaluated, and the visibility of the IAC was assessed by three examiners across four equal 1 cm-wide regions, from anterior to posterior (Areas 1 to 4). For CBCT, reformatted panoramic (CRP) views were generated using curved multiplanar reformatting at the mandibular mid-root level within the software. Four cross-sectional images were obtained for each region. Visibility was rated as visible (score=1) or non-visible (score=0) across the three imaging modalities. Statistical significance was set at P value<0.05. Results: Across all three radiographic modalities, the inferior border of the IAC was more consistently visible than the superior border. The highest visibility of the inferior border was observed in Area 4, with visibility rates of 92.1% for cross-sectional CBCT, 91.5% for CBCT-reformatted panoramic, and 92.4% for CP. The lowest visibility was found at the superior border in Area 2, with visibility rates of 86.9% for cross-sectional CBCT, 80.2% for CBCT-reformatted panoramic, and 67.4% for CP. Conclusion: Visualization of the IAC in the distal area of the mental foramen is more challenging than in other areas across all radiographic modalities. Given the superior visibility levels observed in CBCT images, especially for the superior border in Areas 1, 2, and 3, CBCT is recommended over CP radiography.