1. Department of Oral and Maxillofacial Surgery, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Korea.
2. Division of Oral and Maxillofacial Surgery, Department of Dentistry, Oral and Maxillofacial Surgery, Ajou University School of Medicine, Suwon, Korea.
3. Department of Occupation and Environment, Konkuk Univiersity School of Medicine, Chungju, Korea.