1. Department of Prosthetic Dentistry, University of Kuopio, PB 1627, 70211 Kuopio, Finland
2. Department of Preventive Dentistry and Cariology, University of Kuopio, PB 1627, 70211 Kuopio, Finland
3. Department of Cariology, Institute of Dentistry, University of Helsinki, Mannerheimintie 172, 00300 Helsinki, Finland
4. Geriatric Unit, Helsinki University Central Hospital, Finland