Evaluation of Facial Soft Tissue Angles in Adolescents with Angle Class I, II, and III Malocclusion Using Profile...

Background/Objectives: Soft tissue profile plays a crucial role in orthodontic diagnosis and treatment planning. However, limited data exist regarding differences in facial soft tissue angles among adolescents with different classes of malocclusion. This study aimed to evaluate variations in soft tissue facial angles among patients with Angle Class I, II, and III malocclusions aged 12-16 years using profile photographs. Methods: This retrospective observational study included 489 patients (330 females and 159 males; mean age 13.69 ± 1.30 years) examined between January 2008 and December 2018. 3D Slicer (Brigham and Women's Hospital, Boston, MA, USA) was used only for landmark positioning and coordinate extraction from 2D profile photographs. Five facial angles were measured: Nasion-Nose tip-Pogonion (Na-T-Pg), Glabella-Subnasale-Pogonion (Gl-Sn-Pg), Pogonion-Nasion-Upper lip (Pg-Na-Ls), Pogonion-Nasion-Lower lip (Pg-Na-Li), and Pogonion-Subnasale-Upper lip (Pg-Sn-Ls). Statistical analysis was performed using R software, including ANOVA and t-tests, with significance set at p < 0.05. Results: Patients with Class III malocclusion demonstrated significantly higher mean values of the Na-T-Pg and Gl-Sn-Pg angles and lower values of the Pg-Na-Ls, Pg-Na-Li, and Pg-Sn-Ls angles compared with Class I and Class II malocclusions (p < 0.05), indicating mandibular protrusion. Conversely, Class II malocclusion showed lower Na-T-Pg and Gl-Sn-Pg angles and higher Pg-Na-Ls, Pg-Na-Li, and Pg-Sn-Ls values, consistent with mandibular retrusion relative to the maxilla. No clinically significant sex-related differences were observed in most parameters. Conclusions: Significant differences in facial soft tissue angles exist among adolescents with different malocclusion classes. These findings highlight the importance of soft tissue analysis in orthodontic diagnosis and may support the development of artificial intelligence-based tools for automated malocclusion assessment and treatment planning.