1. Department of Oral and Maxillofacial Surgery, Section of Dentistry, Armed Forces Capital Dental Hospital, Armed Forces Medical Command, Seongnam, Korea
2. Biomedical Research Institute, Seoul National University Bundang Hospital, Seongnam, Korea
3. Department of Radiology, Seoul National University Bundang Hospital, Seongnam, Korea
4. Department of Biostatistics, Korea University College of Medicine, Seoul, Korea