Three-dimensional evaluation of orofacial movements during articulation in patients with skeletal Class III malocclusion with mandibular asymmetry

PurposeThis study aimed to compare the perioral soft tissue movements in patients with skeletal Class III malocclusion with and without mandibular asymmetry during sound articulation.Materials and MethodsPatients with skeletal Class III facial deformity with mandibular asymmetry (asymmetric facial deformity; AFD, n = 21), without mandibular asymmetry (symmetric facial deformity; SFD, n = 27), and control skeletal Class I healthy individuals (n = 24) participated in this study. Perioral soft tissue movements were recorded during the articulation of /apa/, /ipi/, /upu/, /epe/, and /opo/ using a three-dimensional motion capture system. The asymmetry index (AI) of the range of movements of the commissure points on both sides was compared among the three groups by Kruskal-Wallis test and Dunn-Bonferroni test. Additionally, the correlation between the AI and the range of menton (Me) deviation was examined among patients in the SFD or AFD group by Spearman's correlation test.ResultsAI on the vertical and sagittal dimensions during the /ipi/ sound articulation in the AFD group was significantly lower than in the other two groups (p < 0.05). In the AFD and SFD groups, AI on the vertical dimension was significantly correlated with Me deviation during /ipi/ sound articulation, as well as on the sagittal dimension during /apa/, /ipi/, /upu/, and /epe/ sound articulation (p < 0.05).ConclusionAFD patients displayed more asymmetric perioral soft tissue movements than SFD patients during bilabial sound production.