1. Division of Population and Patient Health; King's College London Dental Institute; London UK
2. Departamento de Odontología Social; Facultad de Estomatología; Universidad Peruana Cayetano Heredia; Lima Perú
3. Department of Oral Public Health; Institute of Dentistry; University of Helsinki; Helsinki Finland
4. Department of Community Dentistry; Institute of Dentistry; University of Oulu; Oulu Finland
5. National Institute for Health and Welfare; Helsinki Finland
6. Department of Oral Public Health; Institute of Dentistry; University of Eastern Finland; Kuopio Finland
7. Department of Oral and Maxillofacial Surgery; Kuopio University Hospital; Kuopio Finland