[Histological aspects of tooth bleaching technics].

The chemical principles of tooth bleaching are detailed in order to analyze scanning microscopy data obtained following internal and external bleaching tooth bleaching appears harmless to the enamel structure providing no etching is applied prior to bleaching. Previous enamel undermining appears to increase the porosity along preexisting cracks. Internal bleaching gives way to enamel and dentinal demineralization, which is of particular importance at the dento enamel junction. The biological effects of bleaching on dental hard tissues must be viewed in light of the clinical indications for these procedures.