1. Institute of Dentistry; University of Turku; Turku Finland
2. Department of Infectious Disease Surveillance and Control; National Institute for Health and Welfare (THL); Helsinki Finland
3. Institute of Dentistry; University of Helsinki; Helsinki Finland
4. Department of Oral & Maxillofacial Surgery; Helsinki University Central Hospital; Helsinki Finland
5. Unit of Living Conditions, Health and Wellbeing; Department of Environmental Health in Environmental Epidemiology Unit; National Institute for Health and Welfare (THL); Kuopio Finland
6. Institute of Dentistry; University of Eastern Finland; Kuopio Finland
7. Department of Oral and Maxillofacial Surgery; Kuopio University Hospital; Kuopio Finland