Facial asymmetry of the hard and soft tissues in skeletal Class I, II, and III patients

Abstract

To investigate and compare the facial asymmetry (hard and soft tissues) among skeletal Class I, II, and III patients. A total of 221 subjects, including skeletal Class I (n = 80), skeletal Class II (n = 75), and skeletal Class III (n = 66), were included in the study. CBCT, 22 skeletal landmarks, and 10 soft tissue landmarks were used for the measurements and the asymmetry index was calculated to assess the facial asymmetry. Statistical analyses included one-way ANOVA, Kruskal–Wallis test, and Spearman correlation analysis. The skeletal Class III patients presented greater asymmetry than Class II patients for 10 hard tissue landmarks and 3 soft tissue landmarks (p < 0.05). High correlation of asymmetry was found between four soft tissue landmarks and their corresponding skeletal landmarks (rs ≥ 0.71), as well as Me and ANS (r > 0.86). The ANS and Me in 21.3% patients deviated to contralateral sides. The skeletal Class III patients had more facial asymmetry than the Class II patients. Soft tissues showed similar asymmetry as the underlying hard tissues rather than a compensation of the hard tissue asymmetry. The inconsistency in the deviation of Me and ANS may exacerbate facial asymmetry.

Imaging and 3D Analysis Based on Two or More Three-Dimensional CBCT Recordings before and after Orthodontic Treatment and Maxillofacial Therapy

“…Basic forms of comparison, such as the evaluation of metric features and the calculation of distances between landmarks on 3D models, help determine the relative agreement or similarity between external structures or identify significant differences [15]. More complex data processing, such as landmark-based analysis through geometric morphometrics or surfacebased processing, facilitates the exploration and representation of spatial relationships between craniofacial components [16,17].…”