Cranial Base Morphology and Mandibular Growth in Skeletal Deep Bite: A Longitudinal Study in Prepubertal Children

Background: Skeletal deep bite malocclusion (Angle Class II division 2) represents a common vertical skeletal discrepancy characterized by excessive anterior overbite and a hypodivergent craniofacial growth pattern. The contribution of cranial base morphology to mandibular growth direction during early development remains incompletely understood. Objective: To evaluate the relationship between cranial base morphology and maxillofacial growth patterns in children with skeletal deep bite, using a longitudinal cephalometric approach. Materials and Methods: This retrospective longitudinal cohort study included 96 prepubertal patients aged 7-10 years (54 with skeletal deep bite, 42 Angle Class I dentoalveolar controls). Skeletal deep bite was defined by overbite > 4 mm and mandibular plane angle (FMA) < 22°. A total of 298 standardized lateral cephalometric radiographs (2-4 per subject; mean follow-up 24 ± 4 months) were analyzed. Twenty-two cephalometric parameters were assessed. Longitudinal changes were evaluated using repeated-measures analysis, and predictors of deep bite severity were identified using multiple linear regression. Results: Compared with controls, the deep bite group exhibited significantly reduced mandibular plane angle (18.5° vs. 24.0°), smaller gonial angle (104.3° vs. 111.0°), and decreased lower anterior facial height (86.3 mm vs. 92.0 mm; all p < 0.001). Differences in cranial base morphology were modest, including reduced anterior cranial base length (58.6 mm vs. 60.0 mm; p = 0.031). Regression analysis identified gonial angle and lower anterior facial height as significant predictors (R² = 0.58). Longitudinal analysis suggested early tendencies toward forward mandibular rotation and reduced vertical growth rate over the observation period. Conclusions: In prepubertal children, skeletal deep bite is associated with early tendencies toward reduced vertical facial development and forward mandibular rotation. Cranial base morphology appears to be associated with mandibular growth direction as a secondary modulatory factor rather than a primary determinant. Early identification of hypodivergent growth indicators may facilitate timely interceptive orthodontic strategies.