1. Medical and Dental Center of the Military Police of Rio Grande do Sul; Porto Alegre RS Brazil
2. Department of Community Dentistry; School of Dentistry; Federal University of Rio Grande do Sul; Porto Alegre RS Brazil
3. Postgraduate Program; School of Dentistry; Federal University of Rio Grande do Sul; Porto Alegre RS Brazil
4. National Institute on Aging, Translational Gerontology Branch; Intramural Research Program; Baltimore MD USA
5. Department of Periodontics; School of Dentistry; University of Maryland; Baltimore MD USA