Time-Efficient TiO2-Assisted Hydrogen Peroxide Bleaching Under LED Irradiation: Whitening Performance and Cellular Responses
Year: 2026
Type: article
Abstract: In-office bleaching with hydrogen peroxide (HP) is effective, but prolonged application times and multiple sessions may alter the enamel surface and trigger adverse cellular responses. TiO2-assisted HP bleaching could enhance whitening efficacy while reducing the application time. This study evaluated whether TiO2 incorporation could improve bleaching efficiency with a shorter application time while limiting adverse enamel and cellular effects. Forty enamel–dentin specimens were assigned to four bleaching protocols (n = 10): 40% HP for 40 min (G1), 40% HP containing 1 wt% TiO2 for 20 min (G2) or 40 min (G3), and 40% HP for 20 min (G4). All groups received standardized LED irradiation. Evaluations included color change, enamel microhardness, and surface roughness. Conditioned media were applied to human dental pulp stem cells (hDPSCs) and evaluated the cellular oxidative response in hDPSC lysates using a commercial Human ROS ELISA assay. Cellular metabolic activity and morphology were assessed by MTT assay, phase-contrast microscopy, and scanning electron microscopy (SEM), respectively. All protocols resulted in measurable whitening, and G2 showed whitening performance comparable to G1 despite half the application time. G1 showed the lowest post-treatment microhardness and the highest surface roughness, whereas G4 showed the least alteration to enamel. ROS ELISA measurements differed among the experimental conditions, with the highest level observed in G3. All conditioned media reduced hDPSC metabolic activity related to the control, with differences among the bleaching protocols and exposure periods. According to the results of this in-vitro study, incorporating 1 wt% TiO2 into HP bleaching gel under LED irradiation enabled a shorter application protocol to achieve whitening comparable to the conventional longer-duration protocol while reducing enamel surface alterations. Although TiO2-assisted protocols produced higher cellular ROS levels, these levels did not show a directly proportional relationship with cellular metabolic activity or morphology.
Source: Inorganics
Language: English
Topic: Dental Erosion and Treatment
Subfield: General Dentistry
Field: Dentistry
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $2,654
OpenAlex ID: W7225640895