Hydrogen Peroxide Tooth Whitening Agent Alters the Protein Content of Enamel

Tooth whitening is a relatively quick, inexpensive and conservative treatment options for managing discoloured teeth and can be applied easily by dentists and patients. Bleaching agents at various concentrations have been marketed for dental office and home application. The aim of this study was to assess the effects of 30% hydrogen peroxide on the protein content of enamel. The effect of bleaching for 30 minutes with 30% hydrogen peroxide on the protein content of sound enamel was also investigated. Protein was extracted from the enamel by precipitation with trichoracetic acid after dissolution of the inorganic phase and the amount of protein was quantified using the Lowry and the Bradford protein assays. From 0.01g of sound enamel, the mean amount of protein detected using the Lowry, and the Bradford assays were50.56µg ± 0.06, and 3.08µg ± 0.01 respectively. After surface treatment of the enamel with 30% hydrogen peroxide, the mean protein values using same protein assays were 9.2 µg ± 0.04, and 1.2 µg ± 0.004 respectively. These results indicate that bleaching treatment with 30% hydrogen peroxide resulted in a significant reduction in protein content. The contribution of the protein modified or extracted from mature, sound enamel by bleaching with 30% hydrogen peroxide to the mechanical properties of enamel should be further investigated.