ESR Detection of ROS Generated by TiO2 Coated with Fluoridated Apatite

Specific materials used in the manufacture of dentures may enhance the removal of micro-organisms. The ultraviolet A (UVA) irradiation of acrylic resin containing titanium dioxide (TiO2) generates reactive oxygen species (ROS) by photocatalysis that shows antibacterial effects. In this study, we tested the hypothesis that TiO2 coated with fluoridated apatite (FAp-TiO2) can generate ROS via photo-catalysis by using electron spin resonance (ESR), and that acrylic resin containing FAp-TiO2 can show antifungal properties by measuring the viability of Candida albicans. We demonstrated that hydroxyl radicals (HO•) were generated through excitation of TiO2, TiO2 coated with apatite (HAp-TiO2), and FAp-TiO2. The HO• generation through excitation of FAp-TiO2 was higher than that of TiO2 and HAp-TiO2. Regarding antifungal activity, cell viability on acrylic resin containing FAp-TiO2 was lower than that of TiO2 and HAp-TiO2. FAp-TiO2 showed superior photocatalytic effects, and these characteristics may lead to novel methods for the clinical application of denture-cleaning treatments.