ETEP (Etiolgy and Therapy of Periodontal Diseases) Research Group, University Complutense, Madrid, Spain. King's College London School of Medical Education, London, UK. Microbiology, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK. Piracicaba Dental School, UNICAM, Piracicaba, SP, Brazil. Department of Dentistry and Oral Health, Faculty of Health, Aarhus Universitet, Aarhus C, Denmark. Charite, Berlin, Germany. Manchester University, Manchester, UK. Oral Rehabilitation, University of Talca, Talca, Chile. University of Minnesota School of Dentistry, Minneapolis, MN, USA. Periodontology, University of Turku, Turku, Finland. Department of Oral Biology, School of Dentistry, University of Leeds, Leeds, UK. Periodontology, University of Giessen, Giessen, Germany. Centre for Advanced Research in Public Health, FISABIO Foundation, Valencia, Spain. Periodontology, University of Geneva, Geneva, Switzerland. Katholieke Universiteit Leuven, Leuven, Belgium. Oral Health Cooperative Research Centre, Melbourne Dental School, The University of Melbourne, Melbourne, Australia. Periodontology, Hebrew University and Hadassah Medical Center, Jerusalem, Israel. Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam, The Netherlands.