1. Department of Oral and Maxillofacial Surgery, Yonsei University College of Dentistry, Seoul, Korea.
2. Department of Dentistry, Catholic Kwandong University International St. Mary's Hospital, Incheon, Korea.
3. Department of Oral and Maxillofacial Surgery, Gangnam Severance Hospital, Yonsei University College of Dentistry, Seoul, Korea.
4. Oral Cancer Research Institute, Yonsei University College of Dentistry, Seoul, Korea.