Mahesh K.P.OZhao, Zi QinZi QinZhaoLiu, Hsiao YangHsiao YangLiuLai, Kuan-TingKuan-TingLaiEDDIE HSIANG HUA LAILin, Hong-PingHong-PingLinYU-CHIH CHIANG2023-05-042023-05-0420221876-1070https://scholars.lib.ntu.edu.tw/handle/123456789/630742Background: Tooth discoloration is caused by variety of complex factors that are either inherent or extrinsic in nature. High concentrations (40%) of H2O2 used for in-office tooth bleaching that increase the risk of bleaching sensitivity, enamel porosity and gingival irritation. Photocatalytic degradation method is a promising way to bleaching the tooth using low concentration of H2O2. Methods: Template free Fe2O3 nanoparticles decorated SiO2/MgO nanocomposite spheres are evaluated for photocatalytic degradation of dyes and stains under UVA1 light illumination. Significant findings: SiO2/MgO/Fe2O3 photocatalyst demonstrated 90% degradation of Congo red dye with 1% H2O2 in 30 min under UVA1 light illumination. Subsequently, stained natural human teeth were satisfactorily bleached using SiO2/MgO/Fe2O3 catalyst with 1% H2O2 under UVA1 light illumination due to the generation of •OH and •O2 free radicals with the support of Photo-Fenton process. Cell viability assay indicated that human gingival fibroblasts favorably respond to the light irradiated SiO2/MgO/Fe2O3 photocatalyst associated with H2O2. The 3D surface examination of bleached enamel surfaces by confocal laser scanning microscope (CLSM, Olympus LEXTTM OLS5000) showed no significant changes. Using SiO2/MgO/Fe2O3 photocatalyst in conjunction with very low concentrations of H2O2 under UVA1 light illumination provides a safe and highly efficient strategy for dental bleaching application.Tooth bleaching; Hydrogen peroxide; Ferric compounds; Magnesium oxide; Catalysis; Photo-fenton process; DEGRADATION; ACID; HETEROJUNCTIONS; NANOPARTICLES; PHOTOTHERAPY; OXYGENjournal article10.1016/j.jtice.2022.1044292-s2.0-85132693922WOS:000815956000004https://api.elsevier.com/content/abstract/scopus_id/85132693922