Jiang T, et al. - Experts tested the presumption that fluorescence of dentin came from dentin phosphoprotein (DPP) and that bleaching agents might bleach dentin by oxidizing DPP. Findings suggested the responsibility of DPP for the fluorescent properties of dentin. Authors noted a probability of hydrogen peroxide (HP) to bleach dentin by the oxidization of aromatic amino acids in DPP. There is a great significance of these findings in promoting the further understanding of the mechanism of tooth bleaching and the fluorescent property of normal dentin.