1. Department of Orthodontics, Gangnam Severance Dental Hospital, Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, Korea.
2. Department of Orthodontics, Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, Korea.
3. Biostatistics Collaboration Unit, College of Medicine, Yonsei University, Seoul, Korea.