1. Department of Oral and Maxillofacial Surgery, Institute of Dentistry, University of Turku, Turku, Finland
2. Department of Oral and Maxillofacial Diseases, Turku University Hospital, Turku, Finland
3. Department of Oral and Maxillofacial Diseases, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
4. Department of Community Dentistry, University of Turku, Turku, Finland