THE IMPACT OF VOLUME ORIENTATION ANGLE IN THE SAGITTAL PLANE ON THE MEASUREMENT OF ALVEOLAR BONE WIDTH IN THE POSTERIOR MANDIBLE USING CBCT

Background and Objective: Linear measurements of alveolar bone using cone-beam computed tomography (CBCT) may potentially be influenced by the sagittal volume orientation during image reconstruction. Considering the clinical importance of measurement accuracy in implant surgery, this study aimed to evaluate the effect of sagittal reconstruction angle of CBCT on alveolar ridge width in the posterior mandible of subjects with a normal facial pattern. Materials and Methods: In this cross-sectional study, 165 CBCT scans were selected. During the reconstruction phase, the sagittal plane was oriented at seven different angles (from OP to OP + 30° in 5° intervals), and alveolar ridge width was measured at each angle. Data were analyzed using SPSS version 26 with repeated-measures ANOVA, Bonferroni post-hoc tests, and the intraclass correlation coefficient (ICC) with a significance level of 0.05. Results: Sagittal volume orientation significantly affected the measured alveolar ridge width (p < 0.001). With increasing angles from OP to OP + 15°, the mean ridge width increased progressively from 11.18 ± 1.60 mm to 12.00 ± 1.59 mm, remaining nearly constant at higher angles. The maximum width was observed at OP + 30° (12.07 ± 1.58 mm), which was significantly greater than other angles (p < 0.001). Conclusion: Increasing the sagittal reconstruction angle of CBCT volumes significantly increases measured alveolar bone width in the posterior mandible. Rotating the volume from the occlusal plane toward the mandibular plane produced a progressive and clinically relevant widening, with OP to OP+15° yielding approximately 0.8–0.9 mm of additional width. This effect results from posterior displacement of the cross-sectional plane, which intersects broader regions of the mandibular body as the orientation angle increases.