Novel Yellow Light Responsive SnO2/SnS2 Piezo-photocatalyst with Excellent Performances for Tooth Whitening and Biofilms Eradication

Abstract

Oral problems caused by pathogens and tooth discoloration have posed great threat to public health in recent years. In time killing cariogenic bacteria and removing surface pigments are the key point to treat yellow teeth to restore healthy whitening. Piezo-photocatalysis has been proved to be one such effective strategy for treating yellow teeth problems. However, few effective and safe nanomaterials have been developed to address this issue in the oral fields. Here, it is proposed for the first time that a yellow-light responsive SnO2/SnS2 heterostructures can be used for piezo-photocatalytic biofilm eradication and tooth whitening. Initially XRD and HRTEM results have experimentally verified the formation of SnO2/SnS2 heterostructures. Then UV-Vis DRS spectra indicate that the absorbance in the visible region can be effectively improved after formation of SnO2/SnS2 heterostructures. Subsequently yellow light with excellent biocompatibility is combined with ultrasonic to explore the piezo-photocatalytic performances of SnO2/SnS2 for tooth whitening and biofilms removal. The results demonstrate that the SnO2/SnS2 heterostructures prepared with the molar ratio of TAA:SnO2 at 1:1 for 3 h exhibited the best piezo-photocatalytic performances. The degradation efficiency for the food colorant of Indigo Carmine can reach 94.12%, which is much higher than that of single SnS2 (48.31%), single SnO2 (near zero) and single treating way of only irradiation (63.03%) and only ultrasonic (79.41%). Simultaneously, excellent piezo-photocatalytic tooth whitening effect could be found on the stained teeth by the heterostructures. Moreover, the SnO2/SnS2 heterojunctions exhibited excellent piezo-photocatalytic performances in bacteria killing and biofilm removal and the antibacterial efficiencies of SnO2/SnS2 heterojunctions could reach 77.3% and 56.5% for planktonic S. mutans and biofilms, respectively. In addition, excellent biocompatibility including tiny cytotoxicity and negligible enamel damage could be found in the synergistic treating process of SnO2/SnS2 heterostructures. The in-depth mechanism investigation indicates that the improved piezo-photocatalytic performances were due to the increased carriers separation efficiency and ROS productivity of SnO2/SnS2 heterostructures, demonstrating the great potential of SnO2/SnS2 heterostructures for future dental care fields.