Objectives: This study aimed to determine the efficacy of a combination of photocatalysts—hydrogen peroxide at a low concentration (3.5%) and titanium dioxide (TiO 2 )—activated at a wavelength of 405 nm using quantitative light-induced fluorescence (QLF) technology, and to quantify their tooth-bleaching efficacy using fluorescence images obtained from QLF technology. Materials and methods: Forty bovine incisors were extrinsically stained according to Stookey's method, and were randomly divided into four groups (n = 10 per group). Two bleaching solutions were prepared by mixing 3.5% H 2 O 2 with 0.05% of anatase and rutile TiO 2 powders. These solutions were applied to the stained teeth using a microbrush and then irradiated for 15 min at either 306 or 405 nm to activate the bleaching agent. The color difference (ΔE * ) was assessed before and after every 5 min of treatment. The ΔE * and the changes in the fluorescence loss (ΔΔF) were obtained from white-light and fluorescence images, respectively. Results: All of the low-H 2 O 2 /TiO 2 treatments caused significant tooth-bleaching efficacy after irradiation at 306 and 405 nm (p < 0.05). The results did not differ significantly between the two wavelengths (p > 0.05), but the bleaching efficacy was greater with anatase TiO 2 at 306 nm and rutile TiO 2 at 405 nm. Analysis of the fluorescence images revealed that the ΔF values increased significantly in all groups with the treatment time (p < 0.05). There was a statistically significant correlation between ΔE * and the change in ΔΔF (r = 0.822, p < 0.001). Conclusions: Combining low-H 2 O 2 /TiO 2 with QLF technology at 405 nm has an efficacy of tooth-bleaching as a less harmful and biofriendly method, while the fluorescence images obtained by QLF technology could be used to assess tooth-bleaching.
Bibliographical notePublisher Copyright:
© 2018 Elsevier B.V.
All Science Journal Classification (ASJC) codes
- Pharmacology (medical)