1. Division of Oral and Maxillofacial Surgery, Department of Dentistry, Korea University Ansan Hospital, Ansan 15355, Republic of Korea
2. Department of Periodontics, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
3. Division of Oral & Maxillofacial Surgery, Department of Dentistry, Hanyang University College of Medicine, Seoul 04763, Republic of Korea