Accuracy and Reliability of Orthopantomogram and Cone Beam Computed Tomography in Assessing Mandibular Buccal Shelf Anatomy Across Various Skeletal Malocclusions and Vertical Growth Patterns

Objective To assess the diagnostic accuracy and reliability of orthopantomogram (OPG) compared to cone beam computed tomography (CBCT) in evaluating the mandibular buccal shelf anatomy, with specific emphasis on the proximity to the inferior alveolar nerve canal (IANC), across various skeletal malocclusions and vertical growth patterns. Methods A cross-sectional study with a retrospective design was conducted using OPG and CBCT images of 90 patients obtained prior to treatment, stratified based on skeletal malocclusion into Class I, II, and III groups ( n = 30 each), and further subdivided based on facial divergence (hypodivergent, normodivergent, hyperdivergent). Linear measurements extending from the cementoenamel junction (CEJ) to the superior margin of the IANC were obtained at eight predefined anatomical landmarks. Independent t -test and one-way analysis of variance were used for data analysis, considering P < .05 as statistically significant. Results OPG and CBCT measurements showed no statistically significant differences across all malocclusion and growth patterns ( P > .05). A consistent decrease in CEJ to IANC distance from the mesial CEJ of the first molar to the distal CEJ of the second molar was observed, most pronounced in hyperdivergent individuals. Class III hypodivergent subjects exhibited the greatest bone height (21.19 ± 1.28 mm), whereas Class II hyperdivergent individuals showed the lowest bone height (15.68 ± 1.72 mm), indicating a closer proximity of the IANC. Conclusion OPG is a reliable alternative to CBCT for buccal shelf assessment, offering reduced radiation exposure and cost. Anatomical variations across skeletal and vertical growth patterns significantly impact screw placement safety, emphasizing the need for individualized site selection based on malocclusion and divergence patterns.