1. Institute of Dentistry; University of Eastern Finland; Kuopio Finland
2. Oral and Maxillofacial Department; Kuopio University Hospital; Kuopio Finland
3. Department of Community Dentistry; Institute of Dentistry; University of Turku; Turku Finland
4. Research Unit of Oral Health Sciences; University of Oulu; Oulu Finland
5. Oral and Maxillofacial Department; Medical Research Center Oulu; Oulu University Hospital; Oulu Finland