AIMS: To Assess the Effect of 10% Carbamide Peroxide and 25% Hydrogen Peroxide Activated by an Led Lamp, on the Morphology of the Enamel Surface and to Compare the Effect of the Two Treatments [Estudo Com Microscópio Electrónico de Varrimento, das Alterações Morfológicas da Superfície do Esmalte, Após Tratamento Com Dois Sistemas de Branqueamento]