Factors influencing submandibular fossa visibility on panoramic images: a comparative CBCT study

This study aimed to investigate the variables affecting the visibility of the submandibular fossa (SF) on panoramic images, including SF depth and types, age, gender, presence or absence of tooth, location of mandibular canal, and alveolar bone thicknesses.

Cone beam computed tomography (CBCT) images and conventional panoramic images of 150 patients were analyzed retrospectively. The visibility of the SF on panoramic images was compared with its depth and adjacent alveolar bone thicknesses on CBCT. Predictive variables affecting the SF visibility were identified, and binary logistic regression analysis was performed.

Based on CBCT measurements, the SF depth was ≥ 2 mm in 65% of the hemi-mandibles with radiolucent area (26.7%). A significant difference was observed between the SF visibility on panoramic images and its depth, and the lingual cortical bone thickness as measured on CBCT. When the SF was visible and not, the mean SF depth was 2.24 ± 0.97 mm and 1.6 ± 0.8 mm, and lingual cortical bone thickness was 1.27 ± 0.47 mm and 1.53 ± 0.49, respectively. Regression analysis revealed significant associations between SF visibility and gender (Odds ratio (OR) = 3.28, 95% confidence interval (CI): 1.77-6.09), age (OR = 0.96, 95% CI: 0.94-0.98), SF depth (OR = 2.01, 95% CI: 1.43-2.81), and lingual cortical bone thickness (OR = 2.02, 95% CI: 1.30-3.16).

A prominent radiolucent SF on panoramic images indicates a deeper fossa and thinner lingual cortical bone, necessitating caution by clinicians during surgical planning.