[1] Univ Helsinki, Res Lab, Inst Dent, Biomedicum Helsinki, FIN-00014 Helsinki, Finland
[2] Univ Helsinki, Inst Dent, HUCH, Dept Oral & Maxillofacial Dis, Helsinki, Finland
[3] Univ Helsinki, Cent Hosp, Dept Internal Med, Helsinki, Finland
[4] Invalid Fdn, Orthopaed Hosp, ORTON Res Inst, Helsinki, Finland
[5] Univ Oulu, Publ Hlth Lab, Oulu, Finland
[6] Univ Oulu, Dept Med Microbiol, Oulu, Finland