1. The Health Center of Leppävaara, City of Espoo, Espoo, Finland
2. Department of Oral and Maxillofacial Diseases, Head and Neck Center, University of Helsinki, Helsinki, Finland
3. City of Vantaa, Vantaa, Finland
4. Department of General Practice and Primary Health Care, University of Helsinki, Helsinki, Finland
5. Department of General Practice and Primary Health Care, University of Tampere, Tampere, Finland