1. Department of Medicine/Invärtes medicin, Helsinki University Hospital, Biomedicum Helsinki, PO Box 700 -Haartmaninkatu 8-, FIN-00029 HUS, Helsinki, Finland;
2. Institute of Biomedicine/Anatomy, University of Helsinki, Helsinki, Finland;
3. Medico-social, Dental Clinic, Bogazici University, Istanbul, Turkey;
4. Department of Oral and Maxillofacial Diseases, HUCH, Institute of Dentistry, University of Helsinki, Box 41 FIN-00014 Helsinki, Finland;
5. University of Gazi, Faculty of Dentistry, Department of Periodontology, Ankara, Turkey;