1. Graduate student, School of Dentistry, Seoul National University, Korea.
2. Assistant Professor, Department of Orthodontics and DRI, School of Dentistry, Seoul National University, Korea.
3. Associate Professor, Department of Orthodontics and DRI, School of Dentistry, Seoul National University, Korea.
4. Professor, Department of Orthodontics and DRI, School of Dentistry, Seoul National University, Korea.