1. Postgraduate Student, Department of Orthodontics, Graduate School, Kyung Hee University, Seoul, Korea.
2. Assistant Professor, Department of Periodontology, Kyung Hee University School of Dentistry, Seoul, Korea.
3. Assistant Professor, Department of Orthodontics, Kyung Hee University School of Dentistry, Seoul, Korea.
4. Associate Professor, Department of Orthodontics, Kyung Hee University School of Dentistry, Seoul, Korea.