Kyung-In Jeong1, Junho Lee2, In-Woong Um3, Young-Kyun Kim1,4. 1. 1 Department of Oral and Maxillofacial surgery, Section of Dentistry, Konyang University Hospital, Daejeon, Korea. 2. 2 Private practice, Zelkova Tree Dental Clinic, Seoul, Korea. 3. 3 Korea Tooth Bank, R&D Institute, Seoul, Korea. 4. 4 Department of Oral and Maxillofacial Surgery, Section of Dentistry, Seoul National University Bundang Hospital, Seongnam City, Korea.