1. Department of Odontology, Section for Periodontology and Oral Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
2. Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
3. Department of Periodontology, Institute of Dentistry, University of Turku, Turku, Finland