[1] ICBS UFRGS, Dept Bioquim, Ctr Estudos Estresse Oxidat, BR-90035003 Porto Alegre, RS, Brazil
[2] Univ Turku, Inst Dent, Turku, Finland
[3] Natl Inst Hlth & Welfare THL, Dept Infect Dis Surveillance & Control, Fin Helsinki, Finland
[4] Univ Helsinki, Cent Hosp, Inst Dent, Helsinki, Finland
[5] Univ Helsinki, Cent Hosp, Dept Oral & Maxillofacial Surg, Helsinki, Finland