1. Institute of Dentistry, Faculty of Health Sciences University of Eastern Finland Kuopio Finland
2. Department of Oral and Maxillofacial Diseases, Faculty of Medicine University of Helsinki, Finland, University Dental Clinic City of Helsinki Finland
3. Department of Community Dentistry, Institute of Dentistry University of Turku Turku Finland
4. Research Unit of Oral Health Sciences, Faculty of Medicine University of Oulu Oulu Finland
5. Medical Research Center Oulu Oulu University Hospital and University of Oulu Oulu Finland