1. Department of Preventive and Social Dentistry, Faculty of Dentistry Universidade Federal do Rio Grande do Sul Porto Alegre Brazil
2. Service of Addiction Psychiatry Hospital de Clínicas de Porto Alegre Porto Alegre Brazil
3. School of Medicine, Graduate Program of Medicine, Neurosciences Pontificia Universidade Católica do Rio Grande do Sul Porto Alegre Brazil
4. Laboratory of Immunobiology, School of Health and Biological Sciences Pontificia Universidade Católica do Rio Grande do Sul Porto Alegre Brazil