Three-Dimensional Midfacial Morphology in Skeletal Class III Patients: Postsurgical Changes and Skeletal Correlates

This study aimed to quantify 3-dimensional (3D) midfacial topography in adults with skeletal Class III malocclusion, evaluate morphologic changes following 2-jaw surgery, and identify skeletal factors associated with postoperative cheek contour. Three-dimensional facial surface data were collected from 72 adults with skeletal Class III malocclusion before and after Le Fort I osteotomy and bilateral sagittal split osteotomy, together with data from 200 age-matched controls. Sectional-line and surface-based analyses were used to characterize midfacial morphology, evaluate postsurgical changes, and compare Class III patients with controls. Regression analyses were performed to examine associations between 3D soft tissue changes and corresponding skeletal movements measured on cephalograms. Patients with skeletal class III malocclusion exhibited a flatter cheek contour before surgery, particularly in the paraorbital and malar regions, although surface analysis showed anterior positioning of the paranasal cheek region. Following 2-jaw surgery, cheek flatness improved, and sectional line measurements approached those of controls. Superior displacement of the posterior nasal spine, corresponding to posterior maxillary impaction, was significantly associated with improvement in cheek contour, whereas forward movement of the maxilla mainly influenced the subnasale, nasal alar, and upper lip regions. These findings provide a quantitative 3D framework for evaluating cheek morphology in adults with skeletal class III malocclusion and suggest that posterior maxillary impaction may contribute to postoperative improvement in cheek contour.