1. Department of Periodontology, Oral Medicine and Oral Surgery, Dentistry Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt‐Universität zu Berlin, and Berlin Institute of Health Berlin Germany
2. Department of Periodontology, Facultad de Odontología Universitat Internacional de Catalunya Barcelona Spain
3. Department of Periodontology, Operative and Preventive Dentistry University Hospital Bonn Bonn Germany