RESUMO
The purpose of this study was to evaluate the influence of a bottled green tea beverage on dentin demineralization with a demineralization gel system <i>in vitro</i>. Samples were cut from bovine root dentin. Each sample was immersed in 8% methylcellulose gel onto which a layer of green tea beverage was placed. For comparison, sugar-free coffee beverage, deionized water, and 0.8-ppm F solutions were used. After two weeks, the treatment solutions were replaced with demineralization solution. The mineral profiles and mineral loss values of the lesions were obtained by transversal microradiography (TMR) after one-week demineralization. The green tea, coffee, and fluoride solution treatments induced a significantly thicker surface layer when compared with the deionized water treatment. In particular, the mineral volume % of the demineralized dentin specimens treated with green tea was approximately seven times higher than that of the de-ionized water treatment. The green tea treatment showed significantly lower mineral loss than the other three treatments. TMR measurements clearly showed that the sugar-free bottled green tea beverage inhibited dentin lesion progression, presumably due to the effect of sub-ppm fluoride levels.