1. Department of Prosthodontics, Gangnam Severance Dental Hospital, College of Dentistry, Yonsei University, Seoul, Republic of Korea.
2. Department of Prosthodontics, School of Dentistry, Seoul National University, Seoul, Republic of Korea.
3. Department of Prosthodontics, School of Dentistry, Kyung Hee University, Seoul, Republic of Korea.
4. Department of Biomaterials & Prosthodontics, Kyung Hee University Dental Hospital at Gangdong, Seoul, Republic of Korea.
5. S-Plant Dental Hospital, Seoul, Republic of Korea.
6. Department of Prosthodonitcs, College of Dentistry, Yonsei University, Seoul, Republic of Korea.
7. Yoo's Dental Clinic, Seoul, Republic of Korea.