1. Department of Oral and Maxillofacial Surgery, Section of Dentistry, SMG-SNU Boramae Medical Center, Seoul, Korea.
2. Department of Oral and Maxillofacial Surgery, School of Dentistry, Seoul National University, Seoul, Korea.
3. Department of Oral and Maxillofacial Surgery, School of Dentistry, Grand Dental Clinic, Seoul, Korea.