1. Department of Oral and Maxillofacial Surgery, Korea University Anam Hospital, Seoul 02447, Republic of Korea
2. Department of Prosthodontics, School of Dentistry, Kyung Hee University, Seoul 02447, Republic of Korea
3. Department of Oral and Maxillofacial Surgery, School of Dentistry, Kyung Hee University, Seoul 02447, Republic of Korea