1. Department of Periodontology Periodontal‐Implant Clinical Research Institute School of Dentistry Kyung Hee University Seoul Korea
2. Department of Periodontology Research Institute for Periodontal Regeneration Yonsei University College of Dentistry Seoul Korea
3. Clinic of Reconstructive Dentistry University of Zurich Zurich Switzerland
4. Institute for Research and Education in Dental Medicine Lugano Switzerland