1. Clinic of Reconstructive Dentistry University of Zurich Zurich Switzerland
2. Department of Periodontology, Kyung Hee University, College of Dentistry, Periodontal‐Implant Clinical Research Institute Kyung Hee University Medical Center Seoul Republic of Korea
3. Faculty of Dentistry Universidad Finis Terrae Santiago Chile
4. Department of Periodontology, Research Institute for Periodontal Regeneration Yonsei University College of Dentistry Seoul Republic of Korea