1. Department of Advanced General Dentistry, Dental Hospital, Yonsei University, Seoul, Korea.
2. Apple Tree Dental Hospital, Ilsan, Korea.
3. Department of Oral and Maxillofacial Surgery, National Health Insurance Corporation Ilsan Hospital, Goyang, Korea.
4. Department of Oral and Maxillofacial Surgery, College of Dentistry, Yonsei University, Seoul, Korea.