1. Department of Biochemistry; Federal University of Rio Grande do Sul (UFRGS); Porto Alegre RS Brazil
2. Faculty of Dentistry; McGill University; Montreal Quebec Canada
3. Department of Periodontology; School of Dentistry; Federal University of Rio Grande do Sul (UFRGS); Porto Alegre RS Brazil
4. Department of Dental Materials and Prosthodontics; Faculty of Dentistry of Ribeirão Preto; University of São Paulo (USP); Ribeirão Preto Brazil