1. Department of Periodontology; Institute of Dentistry; University of Turku; Turku Finland
2. Department of Periodontology; Faculty of Dental Medicine; Hebrew University-Hadassah; Jerusalem Israel
3. Division of Restorative Dentistry & Periodontology; Dublin Dental University Hospital; Trinity College; Dublin Ireland
4. ETEP (Etiology and Therapy of Periodontal Diseases) Research Group; Faculty of Odontology; University Complutense; Madrid Spain
5. Centre for Oral Health Research and Institute of Cellular Medicine; Newcastle University; Newcastle upon Tyne UK
6. Department of Periodontology; University Hospital Wuerzburg; Wuerzburg Germany
7. School of Dentistry & Research Centre for the Study of Periodontal and Peri-implant Diseases; University of Ferrara; Ferrara Italy
8. Department of Periodontology; Istanbul University; Istanbul Turkey