1. Department of Prosthodontics, Ewha Womans University, Seoul, Republic of Korea.
2. Department of Oral and Maxillofacial Surgery, Asan Medical Center, Seoul, Republic of Korea.
3. Department of Prosthodontics & Dental Research Institute, Seoul National University, Seoul, Republic of Korea.
4. Department of Prosthodontics, S-PLANT Dental Hospital, Seoul, Republic of Korea.
5. Department of Medical Statistics, Catholic University of Daegu School of Medicine, Daegu, Republic of Korea.