1. Department of Periodontology, School of Dentistry, Chosun University, Gwangju, Korea.
2. Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, Seoul, Korea.
3. Department of Oral Histology-Developmental Biology and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea.