1. Department of Periodontology, Institute of Dentistry, University of Turku, Turku, Finland.
2. Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brasil.
3. Department of Oral and Maxillofacial Diseases, Helsinki University Central Hospital, Helsinki, Finland.
4. Department of Periodontology, Institute of Dentistry, University of Helsinki, Helsinki, Finland.