1. Department of Public Health Dentistry; Institute of Dentistry; University of Eastern Finland; Kuopio Finland
2. Department of Oral Public Health; Institute of Dentistry; University of Helsinki; Helsinki Finland
3. Oral and Maxillofacial Department; Oulu University Hospital; Oulu Finland
4. Department of Environmental Health; National Institute for Health and Welfare (THL); Kuopio Finland
5. National Institute for Health and Welfare (THL); Helsinki Finland
6. Department of Oral and Maxillofacial Surgery; Kuopio University Hospital; Kuopio Finland