1. Department of Oral and Maxillofacial Surgery, School of Dentistry, Seoul National University, Seoul 110-749, Republic of Korea
2. Department of Oral Biochemistry, School of Dentistry and Dental Research Institute, Seoul National University, Seoul 110-749, Republic of Korea
3. Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul 110-749, Republic of Korea