1. Department of Oral and Maxillofacial Surgery, National Health Insurance Service Ilsan Hospital, 100 Ilsan-ro, Ilsan-donggu, Goyang, Gyeonggi-do 410-719, South Korea e-mail:
2. Department of Oral and Maxillofacial Surgery, Yongin Severance Hospital, 23 Yongmunno, Yongin, Gyeonggi-do 449-930, South Korea e-mail:
3. Department of Biomedical Engineering, AMKorea, Anyang, Gyeonggi-do 431-804, South Korea
4. Professor Department of Oral and Maxillofacial Surgery, College of Dentistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752, South Korea e-mail: