Difference in Condylar Position, Dimension, and Angle Among Different Vertical Skeletal Patterns, A Retrospective CBCT Study

Introduction: This study aimed to evaluate and compare the condylar dimensions, position, and angulation among individuals with different vertical skeletal patterns—hyperdivergent, hypodivergent, and normodivergent—using cone-beam computed tomography (CBCT). The objective was to determine whether vertical skeletal variations influence temporomandibular joint (TMJ) structure and function, providing insights for improved orthodontic diagnosis andtreatment planning. Methods: A retrospective analysis was conducted on CBCT scans from 185 adult patients (370 TMJs) from the orthodontic clinic at the University of Nevada, Las Vegas. Patients were categorized into three vertical skeletal groups based on the Frankfort horizontal-mandibular plane angle (FMA): hypodivergent (< 20°), normodivergent (20°–30°), and hyperdivergent (>30°). Condylar width, length, height, joint spaces, and condylar angulation were measured using OnDemand 3D software. Descriptive statistics, ANOVA, and post hoc analyses were performed to evaluate differences across skeletal patterns, sex, and ethnicity. Results: Significant differences in condylar morphology and position were found among the three skeletal groups. Hyperdivergent individuals exhibited significantly smaller medio-lateral condylar widths (p < 0.05) and reduced superior joint spaces, indicating a higher condylar position within the TMJ. Males had significantly larger condylar dimensions than females, with wider medio-lateral condylar widths and greater superior and posterior joint spaces (p < 0.05). Ethnic differences were also observed; African American participants had significantly greater condylar height, while Caucasian individuals had the largest medio-lateral condylar width compared to Hispanics. Conclusions: This study highlights the influence of vertical skeletal pattern, sex, and ethnicity on condylar morphology and spatial positioning. Hyperdivergent individuals demonstrated distinct condylar adaptations, which may have clinical implications for TMJ assessment and orthodontic treatment planning. Understanding these variations is essential for personalized orthodontic and orthopedic interventions.