In-office bleaching effect with different concentrations of hydrogen peroxide on enamel color and demineralization

Use of hydrogen peroxide in tooth bleaching can cause microscopic alterations such as increasedsurface depressions, irregularities and elevated surface roughness. Therefore, it is of interest to report the enamel surface effects of two in-office hydrogen peroxide (HP) bleaching gels. Forty-eight intact human premolars were sectioned mesio-distally, creating two halves, which were then assigned to 2 groups. Group I (35% HP with calcium; whiteness HP Blue 35%, FGM) or Group II (40% HP with fluoride/potassium nitrate; Opalescence Boost, Ultradent). Bleaching was performed in a single 40-minute session per manufacturer protocol. Baseline and post-treatment measurements were taken using a spectrophotometer (VITA Easyshade) for color and a laser fluorescence device (DIAGNOdent pen, KaVo) for quantifying demineralization. The 40% hydrogen peroxide gel with fluoride and potassium nitrate produced a superior whitening effect; both bleaching agents resulted in comparable levels of enamel surface demineralization.