Sang Min Shin1, You-Min Kim2, Na-Ri Kim3, Yong-Seok Choi4, Soo-Byung Park5, Yong-Il Kim6. 1. Researcher, Department of Orthodontics, School of Dentistry, Pusan National University, Busan, South Korea; researcher, Department of Statistics, College of Nature, Pusan National University, Busan, South Korea. 2. Resident, Department of Orthodontics, Pusan National University Dental Hospital, Yangsan, South Korea. 3. Postgraduate student, Department of Orthodontics, Pusan National University Dental Hospital, Yangsan, South Korea. 4. Professor, Department of Statistics, College of Nature, Pusan National University, Busan, South Korea. 5. Professor, Department of Orthodontics, Dental Research Institute, Pusan National University Dental Hospital, Yangsan, South Korea. 6. Assistant professor, Department of Orthodontics, Institute of Translational Dental Sciences, School of Dentistry, Pusan National University, Yangsan, South Korea; assistant professor, Biomedical Research Institute, Pusan National University Hospital, Busan, South Korea. Electronic address: kimyongil@pusan.ac.kr.
Abstract
INTRODUCTION: The purpose of this study was to determine, by statistical shape analysis of original and mirrored skeletal landmarks, the optimal landmark-based midsagittal reference plane for evaluation of facial asymmetry. METHODS: The study sample comprised 69 patients with facial asymmetry (36 men, 33 women; mean age, 23.0 ± 4.1 years). All landmarks were obtained with cone-beam computed tomography using a 3-dimensional coordinate system. For identifying the landmark-based midsagittal reference plane, the 3 landmarks nearest to the symmetric midsagittal reference plane were selected by ordinary and generalized Procrustes analyses. To verify the 3-landmark-based midsagittal reference plane's compatibility with the symmetric midsagittal reference plane, asymmetry measurements were calculated and tested for each. RESULTS: The 3 nearest landmarks (nasion, anterior nasal spine, and posterior nasal spine) were selected for the 3-landmark-based midsagittal reference plane. The averages of the sums of the squared Euclidean distance and the squared Procrustes distance differences between the 2 configurations and shapes fabricated by the symmetric and landmark-based midsagittal reference planes, respectively, were calculated as 0.121 ± 0.241 mm and 1.69 × 10(-6) ± 3.25 × 10(-6). The testing results for the symmetric and landmark-based midsagittal reference planes were almost the same. CONCLUSION: The results indicated that a 3-dimensional midsagittal reference plane constructed of nasion, anterior nasal spine, and posterior nasal spine could be a valuable tool for the evaluation of patients with facial asymmetry.
INTRODUCTION: The purpose of this study was to determine, by statistical shape analysis of original and mirrored skeletal landmarks, the optimal landmark-based midsagittal reference plane for evaluation of facial asymmetry. METHODS: The study sample comprised 69 patients with facial asymmetry (36 men, 33 women; mean age, 23.0 ± 4.1 years). All landmarks were obtained with cone-beam computed tomography using a 3-dimensional coordinate system. For identifying the landmark-based midsagittal reference plane, the 3 landmarks nearest to the symmetric midsagittal reference plane were selected by ordinary and generalized Procrustes analyses. To verify the 3-landmark-based midsagittal reference plane's compatibility with the symmetric midsagittal reference plane, asymmetry measurements were calculated and tested for each. RESULTS: The 3 nearest landmarks (nasion, anterior nasal spine, and posterior nasal spine) were selected for the 3-landmark-based midsagittal reference plane. The averages of the sums of the squared Euclidean distance and the squared Procrustes distance differences between the 2 configurations and shapes fabricated by the symmetric and landmark-based midsagittal reference planes, respectively, were calculated as 0.121 ± 0.241 mm and 1.69 × 10(-6) ± 3.25 × 10(-6). The testing results for the symmetric and landmark-based midsagittal reference planes were almost the same. CONCLUSION: The results indicated that a 3-dimensional midsagittal reference plane constructed of nasion, anterior nasal spine, and posterior nasal spine could be a valuable tool for the evaluation of patients with facial asymmetry.
Authors: Alexander Juerchott; Muhammad Abdullah Saleem; Tim Hilgenfeld; Christian Freudlsperger; Sebastian Zingler; Christopher J Lux; Martin Bendszus; Sabine Heiland Journal: Sci Rep Date: 2018-08-29 Impact factor: 4.379
Authors: Manuel Pinheiro; Xinhui Ma; Michael J Fagan; Grant T McIntyre; Ping Lin; Gautham Sivamurthy; Peter A Mossey Journal: J Biol Eng Date: 2019-05-17 Impact factor: 4.355