Photothermal-Enhanced Fenton-like Catalytic Activity of Oxygen-Deficient Nanotitania for Efficient and Safe Tooth Whitening

Abstract

The growing demand for charming smiles has led to the popularization of tooth bleaching procedures. Current tooth bleaching products with high-concentration hydrogen peroxide (HP, 30–40%) are effective but detrimental due to the increased risk of enamel destruction, tooth sensitivity, and gingival irritation. Herein, we reported a less-destructive and efficient tooth whitening strategy with a low-concentration HP, which was realized by the remarkably enhanced Fenton-like catalytic activity of oxygen-deficient TiO2 (TiO2–x ). TiO2–x nanoparticles were synthesized with a modified solid-state chemical reduction approach with NaBH4. The Fenton-like activity of TiO2–x was optimized by manipulating oxygen vacancy (OV) concentration and further promoted by the near-infrared (NIR)-induced photothermal effect of TiO2–x . The TiO2–x sample named BT45 was chosen due to the highest methylene blue (MB) adsorption ability and Fenton-like activity among acquired samples. The photothermal property of BT45 under 808 nm NIR irradiation was verified and its enhancement on Fenton-like activity was also studied. The BT45/HP + NIR group performed significantly better in tooth whitening than the HP + NIR group on various discolored teeth (stained by Orange II, tea, or rhodamine B). Excitingly, the same tooth whitening performance as the Opalescence Boost, a tooth bleaching product containing 40% HP, was obtained by a self-produced bleaching gel based on this novel system containing 12% HP. Besides, negligible enamel destruction, safe temperature range, and good cytocompatibility of TiO2–x nanoparticles also demonstrated the safety of this tooth bleaching strategy. This work indicated that the photothermal-enhanced Fenton-like performance of the TiO2–x -based system is highly promising in tooth bleaching application and can also be extended to other biomedical applications.

Copper Doped Carbon Dots for Addressing Bacterial Biofilm Formation, Wound Infection, and Tooth Staining

“…The tooth internal bleaching effect of Cu-CDs was tested with rhodamine B (RhB) stained tooth models. 36 The whitening procedure is shown in Figure 8A. According to the photographs, it is found that the fading degree of the Cu-CD + H 2 O 2 group in the first hour was clearly much stronger than that of the H 2 O 2 group and CD + H 2 O 2 group (Figure 8B).…”

“…95 For the teeth endogenous staining, the complete premolars were divided into two halves by cutting along the buccolingual direction to assess the bleaching power to different internal structures of the tooth. 36 For clinical applications, a more realistic simulation model of intramedullary bleaching was developed to evaluate the significant improvement in dental crown appearance. Similarly to the clinical operation, we cleaned the pulp of all the isolated teeth and abraded the top of the pulp chamber after root removal.…”

“…35 Compared to these invasive bleaching strategies, the degradation of chromogen by chemical whitening based on reactive oxygen species (ROS) is a promising alternative for reducing dental tissue damages. 36 Notably, ROS not only can oxidize color chromogens into colorless small molecules 37 but also can decompose biofilms by decomposing EPS matrix 38 and are considered to be the main antibacterial mechanism. 39 In response, great efforts have been made for the development of promising alternative options showing broadspectrum antibacterial activity and nondrug resistance, 40 such as noble metals, metal oxides, 41 carbon-based materials, 42,43 and drug-delivery platform.…”

Dental Materials for Oral Microbiota Dysbiosis: An Update

“…In addition to nonmetal atoms doping, oxygen-deficient titania (TiO 2-x ) can exhibit better photo-catalytic performance than TiO 2 due to its improved separation of electron-hole pairs and extended visible light absorbance regions (Chen et al, 2011;Naldoni et al, 2012). Hu et al prepared TiO 2-x nanoparticles from TiO 2 based on the solid-state chemical reduction method (Hu et al, 2021). The presence of oxygen vacancy improved the catalytic activity under NIR irradiation and meanwhile, elevated temperature brought from photo-thermal conversion can also kill bacteria (Figure 2C).…”

“…Hu et al. prepared TiO 2-x nanoparticles from TiO 2 based on the solid-state chemical reduction method ( Hu et al., 2021 ). The presence of oxygen vacancy improved the catalytic activity under NIR irradiation and meanwhile, elevated temperature brought from photo-thermal conversion can also kill bacteria ( Figure 2C ).…”