1. Research Unit of Oral Health Sciences, Faculty of Medicine, University of Oulu, Oulu, Finland
2. Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland
3. Institute of Dentistry, University of Eastern Finland, Kuopio, Finland
4. Department of Oral and Maxillofacial Surgery, Kuopio University Hospital, Kuopio, Finland
5. Public Health Evaluation and Projection Unit, Finnish Institute for Health and Welfare (THL), Kuopio, Finland
6. Finnish Institute for Health and Welfare (THL), Helsinki, Finland