Three-dimensional assessment of facial soft tissues, facial asymmetry, and dental arch morphology in patients with skeletal Class II malocclusion at the pubertal growth stage

Three-dimensional (3D) assessment may provide a comprehensive and non-invasive characterization of the facial soft tissues and dental arch morphology associated with skeletal Class II malocclusion. This study aimed to assess and compare facial soft-tissue and dental arch morphology in participants with skeletal Class II malocclusion and Class I controls at the pubertal growth stage and evaluate sex-related differences. The study included 66 children with skeletal Class II malocclusion characterized by mandibular retrusion and 58 Class I controls at cervical vertebral maturation stage 3 (CS3). Three-dimensional facial images and dental models were analysed using linear, angular, landmark-coordinate, surface-symmetry, projection-area, and volumetric measurements. Group and sex effects on these parameters were assessed using two-way analysis of variance. Class II participants exhibited reduced lower facial height (LS mean ± SEM: 43.90 ± 0.38 vs. 45.75 ± 0.40 mm; p < 0.001) and a smaller facial convexity angle (157.55° vs. 162.40°; p < 0.001), together with posterior positioning of the lower lip and soft-tissue pogonion and a smaller mentolabial angle (all p < 0.001). No statistically significant difference in whole-face symmetry was detected between Class I and Class II participants (67.31% vs. 65.73%; p = 0.364). Maxillary intercanine cusp width ( p < 0.001), maxillary intermolar cusp width ( p < 0.001), mandibular intermolar cusp width ( p = 0.036), mandibular mouth floor projection area ( p = 0.044), and volume ( p < 0.001) were smaller in the Class II group. The maxillary-to-mandibular volume ratio was greater in the Class II group ( p = 0.027), whereas palatal projection area and volume did not differ significantly between the groups. Several facial and dental arch dimensions differed between sexes. Skeletal Class II malocclusion with mandibular retrusion was associated with differences in facial soft-tissue profile, while no significant differences in facial symmetry were detected between the groups. Posterior positioning of the lower lip and soft-tissue pogonion was associated with a more convex soft-tissue profile and a smaller mentolabial angle, whereas smaller mouth floor projection area and volume were associated with a greater maxillary-to-mandibular volume ratio. Sex-related differences support consideration of sex in 3D craniofacial assessment.