Institution: | 1. Institute of Dentistry, University of Helsinki, , Helsinki, Finland;2. Department of Oral and Maxillofacial Diseases, Helsinki University Central Hospital, , Helsinki, Finland;3. Institute of Dentistry, University of Turku, , Turku, Finland;4. Division of Periodontology, Department of Dental Medicine, Karolinska Institutet, , Huddinge, Sweden;5. Department of Medicine, Helsinki University Central Hospital, , Helsinki, Finland |