1. Oral and Maxillofacial Department, Central Ostrobothnia Joint Municipal Authority for Social and Health Services, Central Hospital for Central Ostrobothnia, Kokkola, Finland;
2. Medical Research Center, Oulu University Hospital and University of Oulu, Oulu, Finland;
3. Research Unit of Oral Health Sciences, University of Oulu, and Medical Research Center, Oulu University Hospital and University of Oulu, Oulu, Finland;
4. Department of Oral and Maxillofacial Diseases, Faculty of Medicine, University of Helsinki, Helsinki, Finland