1. Department of Oral and Maxillofacial Surgery, Section of Dentistry, Seoul National University Bundang Hospital, Seongnam, Korea.
2. School of Dentistry, Seoul National University, Seoul, Korea.
3. Department of Prosthodontics, Section of Dentistry, Seoul National University Bundang Hospital, Seongnam, Korea.
4. The Hill School, Pottstown, PA, USA.