1. From the Institute of Dentistry (P.J.P., T.V.-R., M.V., K.M.), University of Helsinki, and the Department of Oral and Maxillofacial Diseases, Helsinki University Central Hospital, Helsinki, Finland; the Department of Health and Functional Ability (G.A., T.P., J.S.) and the Department of Molecular Medicine (M.J.), National Public Health Institute, Helsinki, Finland; and the Department of Oral Microbiology (S.A.), Umeå University, Umeå, Sweden.