Chi-Won Seo1, Jae-Min Seo2. 1. Resident, Department of Prosthodontics, Institute of Oral Bio-Science, School of Dentistry, Chonbuk National University and Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Jeonju, Republic of Korea. 2. Associate Professor, Department of Prosthodontics, Institute of Oral Bio-Science, School of Dentistry, Chonbuk National University and Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Jeonju, Republic of Korea. Electronic address: jmseo@jbnu.ac.kr.