Si Yu Hou1,2, Wenwen Zhou1, Hongwei Dai1,2,3, Hai Ming Wong4, Yi Feng Wen5, Jianping Zhou6,7,8. 1. Stomatological Hospital of Chongqing Medical University China, No. 426 Songshi North Road, Chongqing, China. 2. Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China. 3. Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China. 4. Paediatric Dentistry, Faculty of Dentistry, The University of Hong Kong, China, 34 Hospital Road, Hong Kong, Hong Kong. 5. Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University., No. 98 Xiwu Road, Xi'an, Shaanxi Province, China. pyfwen@qq.com. 6. Stomatological Hospital of Chongqing Medical University China, No. 426 Songshi North Road, Chongqing, China. zjp@hospital.cqmu.edu.cn. 7. Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China. zjp@hospital.cqmu.edu.cn. 8. Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China. zjp@hospital.cqmu.edu.cn.
Abstract
BACKGROUND: To investigate changes in facial morphology during the first six months of orthodontic treatment among adult females receiving orthodontic treatment. METHODS: 43 adult females receiving orthodontic treatment were randomly recruited. 3D facial images were taken at baseline (T0), three months (T1), and six months (T2) after treatment initiation. Spatially dense facial landmarks were digitized to allow for sufficient details in characterization of facial features. 3D geometric morphometrics and multivariate statistics were used to investigate changes in mean and variance of facial shape and facial form associated with treatment. RESULTS: We observed statistically significant changes in facial shape across the three treatment stages (p = 0.0022). Pairwise comparisons suggested significant changes from T0 to T1 (p = 0.0045) and from T0 to T2 (p = 0.0072). Heatmap visualization indicated that the buccal and temporal region were invaginated while the labial region became protruded with treatment. The magnitude of shape change was 0.009, 0.004, and 0.010 from T0 to T1, T1 to T2, and T0 to T2, respectively, in unit of Procrustes distance. The average magnitude of change per-landmark was 1.32 mm, 0.21 mm, and 1.34 mm, respectively. Changes in mean facial form were not statistically significant (p = 0.1143). No changes in variance of facial shape were observed across treatment stages (p > 0.05). CONCLUSION: Rate of facial changes was twice as fast during the first three months as that during fourth to sixth month. Buccal and temporal region became invaginated while labial region became protruded with treatment.
BACKGROUND: To investigate changes in facial morphology during the first six months of orthodontic treatment among adult females receiving orthodontic treatment. METHODS: 43 adult females receiving orthodontic treatment were randomly recruited. 3D facial images were taken at baseline (T0), three months (T1), and six months (T2) after treatment initiation. Spatially dense facial landmarks were digitized to allow for sufficient details in characterization of facial features. 3D geometric morphometrics and multivariate statistics were used to investigate changes in mean and variance of facial shape and facial form associated with treatment. RESULTS: We observed statistically significant changes in facial shape across the three treatment stages (p = 0.0022). Pairwise comparisons suggested significant changes from T0 to T1 (p = 0.0045) and from T0 to T2 (p = 0.0072). Heatmap visualization indicated that the buccal and temporal region were invaginated while the labial region became protruded with treatment. The magnitude of shape change was 0.009, 0.004, and 0.010 from T0 to T1, T1 to T2, and T0 to T2, respectively, in unit of Procrustes distance. The average magnitude of change per-landmark was 1.32 mm, 0.21 mm, and 1.34 mm, respectively. Changes in mean facial form were not statistically significant (p = 0.1143). No changes in variance of facial shape were observed across treatment stages (p > 0.05). CONCLUSION: Rate of facial changes was twice as fast during the first three months as that during fourth to sixth month. Buccal and temporal region became invaginated while labial region became protruded with treatment.