1. Clinic of Reconstructive Dentistry, University of Zurich, Zurich, Switzerland.
2. Department of Periodontology, Periodontal-Implant Clinical Research Institute, Kyung Hee University School of Dentistry, Seoul, Korea.
3. Department of Conservative Dentistry, University of Chile, School of Dentistry, Santiago, Chile.
4. Department of Oral Biology, Medical University of Vienna, School of Dentistry, Vienna, Austria.
5. Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Korea.