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