1. a Graduate student, Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
2. b Assistant Professor, Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
3. c Professor and Chairman, Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
4. Corresponding author: Dr Shouichi Miyawaki, Professor and Chairman, Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1, Sakuragaoka, Kagoshima 890-8544, Japan (miyawaki@denta.hal.kagoshima-u.ac.jp)