Reprint requests: Soraya de Mattos Camargo Grossmann, DDS, MS, Faculdade de Odontologia da UFMG, Disciplina de Patologia Bucal, Av. Antônio Carlos, 6627, Pampulha, 31279-901, Belo Horizonte-MG, Brasil
Supported by grants from the Coordination for the Improvement of Higher Education Personnel (CAPES) and the National Council for Scientific and Technological Development (# 301490/2007-4). R.S.G. and R.A.M. are research fellows of CNPq.