Cranial Base Morphology and Mandibular Growth Direction in Skeletal Deep Bite: A Longitudinal Cephalometric Study in Growing Patients

Background: Skeletal deep bite malocclusion (Angle Class II division 2) is a prevalent vertical skeletal discrepancy characterized by excessive anterior overbite and a hypodivergent craniofacial growth pattern. Although its clinical features are well documented, the contribution of cranial base morphology to mandibular growth direction during active development remains incompletely understood. Objective: This longitudinal study aimed to evaluate the relationships between cranial base morphology and maxillofacial growth patterns in growing patients with skeletal deep bite malocclusion compared with subjects presenting Angle Class I dentoalveolar anomalies. Materials and Methods: A retrospective longitudinal cohort of 96 pediatric patients aged 7–10 years was analyzed, comprising 54 subjects with skeletal deep bite malocclusion and 42 controls. A total of 298 standardized lateral cephalometric radiographs obtained over an average follow-up period of 24 months were evaluated. Twenty-two cephalometric parameters were measured, including cranial base, linear, and angular maxillofacial variables. Intergroup comparisons were performed using parametric tests, while longitudinal changes were assessed through repeated-measures analysis. Effect sizes and multiple regression modeling were used to determine predictors of skeletal discrepancy severity. Results: The deep bite group demonstrated a characteristic hypodivergent growth pattern, including significantly reduced mandibular plane angle, decreased gonial angle, and diminished lower anterior facial height (p < 0.001). Mandibular body length was slightly increased, indicating predominant horizontal growth rather than mandibular deficiency. Cranial base analysis revealed moderate reductions in posterior cranial base angulation and anterior cranial base length. Regression analysis identified mandibular plane angle, gonial angle, and lower anterior facial height as the strongest predictors of skeletal deep bite severity (R² = 0.58). Longitudinal evaluation confirmed progressive forward mandibular rotation and reduced vertical growth rate. Conclusions: Skeletal deep bite malocclusion is primarily determined by a hypodivergent growth pattern characterized by reduced vertical facial development and forward mandibular rotation. Cranial base morphology plays a secondary modulatory role by influencing mandibular growth direction. Early identification of reduced vertical growth indicators may improve risk assessment and enable timely interceptive orthodontic interventions.