Morphological alterations in the epithelium of the oral mucosa of rats (Rattus norvegicus) submitted to long-term systemic nicotine treatment - Caldeira, Eduardo José; Carvalho, Cesar Alexandre Fabrega; Padovani, Carlos Roberto; Camilli, José Angelo; Garcia, Progresso José; Cagnon, Valéria Helena Alves (Archives of Oral Biology, 2007)