1. Department of Prosthodontics, Kangwon National University Hospital, Chuncheon 24289, Republic of Korea
2. Department of Prosthodontics, Kyung Hee University Dental Hospital, Seoul 02447, Republic of Korea
3. Department of Oral and Maxillofacial Surgery, School of Dentistry, Kyung Hee University, Seoul 02447, Republic of Korea
4. Department of Prosthodontics, School of Dentistry, Kyung Hee University, Seoul 02447, Republic of Korea