Application of quantitative light-induced fluorescence technology for tooth bleaching treatment and its assessment: An in vitro study

摘要： Objectives: This study aimed to determine the effectiveness of combination of photocatalysts - low concentration of hydrogen peroxide (3.5%) and titanium dioxide (TiO2), activated at a wavelength of 405 nm using quantitative light-induced fluorescence (QLF) technology, and to quantify the tooth-bleaching effect using fluorescence images from QLF technology. Materials and Methods: Forty bovine incisors were extrinsically stained according to Stookey’s method. Two bleaching solutions were prepared by mixing 3.5% H2O2 with 0.05% of anatase and rutile nano-TiO2 powder. These solutions were applied to the stained teeth using a micro-brush and then irradiated for 15 minutes at either 306 or 405 nm to activate the bleaching agent. The color difference was assessed before and after every 5 minutes of treatment. The ?E and ?F were obtained from white-light and fluorescence images, respectively. Results: All the low H2O2/TiO2 treatments caused significant bleaching after irradiation at 306 and 405 nm (p<0.05). There was no significant difference between the wavelengths (p>0.05), but a greater bleaching effect was obtained with anatase-TiO2 at 306 nm and rutile-TiO2 at 405 nm. Analysis of the fluorescence images revealed that the ?F values decreased significantly in all the groups according to the treatment times (p<0.05). There was a statistically significant reverse correlation between ?E and ??F (r= -0.822, p<0.001). Conclusions: Low H2O2/TiO2 with 405 nm of QLF technology demonstrated greater bleaching effect. Furthermore, the fluorescent images from QLF technology showed a possibility for assessment of tooth bleaching.