1. Department of Medicine/Invärtes medicin, Helsinki University Central Hospital, Helsinki, Finland;
2. Institute of Biomedicine/Anatomy, University of Helsinki, Finland;
3. Medico-social Centre, Dental Clinic, Bogazici University, Istanbul, Turkey;
4. ORTON Orthopaedic Hospital of the Invalid Foundation, Helsinki, Finland;
5. Department of Periodontology, Faculty of Dentistry, Ankara University, Turkey;