Low-Intensity Blue Light Enhances Whitening Effect Of Hydrogen Peroxide.

To evaluate the effect of low-intensity blue light on hydrogen peroxide (H2O2)-induced whitening. For color evaluation, model stain disks were immersed in a 1% H2O2 solution. The control group was kept in the dark, while the experimental group was irradiated with blue light at 50 W/m². The L*a*b* values of the discs were measured after 1.5, 3.0, and 4.5 hours, and the ΔE values were calculated by comparing them to the initial values. For radical measurement, terephthalic acid disodium salt was added to the 1% H2O2 solution at 0.01 mol/L, and only the experimental group was irradiated with blue light at 50 W/m². Measurements were taken after 2, 7, 12, and 17 minutes, using an excitation light of 310 nm and a detection light of 425 nm. The amount of radicals was calculated from the 2-hydroxyterephthalic acid, detected. The ΔE values of the model stain disks in each group at 1.5, 3.0, and 4.5 hours were 0.23, 1.58, and 4.45 for the control group, and 9.23, 27.74, and 43.10 for the experimental group, respectively. Additionally, the amounts of radicals in the experimental group were 1.55, 1.77, 1.98, and 2.26 times those of the non-irradiated condition at 2, 7, 12, and 17 minutes, respectively. Low-intensity blue light can promote radical generation by hydrogen peroxide in a short period, potentially enhancing the whitening effect.