1 Department of Social Services and Health Care, Oral Health Care, City of Helsinki, Finland. Electronic address: riitta.saarela@hel.fi.
2 Department of Oral and Maxillofacial Diseases, Faculty of Medicine, University of Helsinki, Finland.
3 Primary Health Care Unit, Kuopio University Hospital, Kuopio, Finland; Folkhälsan Research Center, Helsinki, Finland.
4 Department of Social Services and Health Care, Geriatric Outpatient Clinic, City of Helsinki, Finland.
5 Institute of Dentistry, University of Eastern Finland, Kuopio, Finland; Oral and Maxillofacial Diseases, Kuopio University Hospital, Finland.
6 Department of General Practice and Primary Health Care, University of Helsinki, Finland; Helsinki University Hospital, Unit of Primary Health Care, Finland.