1. Graduate Student, Department of Prosthodontics, Graduate School of Clinical Dentistry, Ewha Womans University, Korea.
2. Seoul Top Dental Clinic, Korea.
3. Assistant Professor, Department of Oral Anatomy, Dental School, Kangnung National University, Korea.
4. Assistant Professor, Department of Prosthodontics, School of Dentistry, Kyung Hee University, Seoul, Korea.