Affiliation: | 1. Private Practice, Dental Office Drs. Sung & Oh, , Seoul, Korea;2. Professor, Department of Prosthodontics, Gangnam Severance Dental Hospital, College of Dentistry, Yonsei University, , Seoul, Korea;3. Associate Professor and Chairman, Department of Prosthodontics, Gangnam Severance Dental Hospital, College of Dentistry, Yonsei University, , Seoul, Korea |