1. a Professor and Department Chair, Department of Orthodontics, Gachon Medical School, Gil Medical Center, Incheon, South Korea
2. b Resident, Department of Orthodontics, Gachon Medical School, Gil Medical Center, Incheon, South Korea
3. c Associate Professor, Department of Preventive Medicine, Gachon Medical School, Gil Medical Center, Incheon, South Korea
4. d Associate Professor, Department of Orthodontics, School of Dentistry, Dental Research Institute, Seoul National University, Seoul, South Korea