1. Division of Oral Diseases, Department of Dental Medicine Karolinska Institutet Stockholm Sweden
2. Section for Clinical Oral Microbiology, Department of Odontology, Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
3. Department of Periodontology, School of Dental Medicine University of Bern Bern Switzerland
4. Department of Periodontology, Institute of Dentistry University of Turku Turku Finland
5. Department of Odontology Umeå University Umeå Sweden