Antimicrobial effect of titanium dioxide after ultraviolet irradiation against periodontal pathogen

Abstract

We focused on the antimicrobial effects of titanium dioxide (TiO₂) after stopping ultraviolet (UV) irradiation as an adjunctive treatment for peri-implantitis in this study. The aim was to determine the continuous photocatalytic effects of TiO₂ after UV irradiation and its antimicrobial activity against periodontal pathogen. The continuous photocatalytic effects of TiO₂ after UV irradiation were determined by electron spin resonance (ESR) spectroscopy using TiO₂ particles of various sizes with various UV irradiation times. In addition, antimicrobial activity against Porphyromonas gingivalis was investigated by quantitation of colony-forming units (CFUs). The results showed that the ESR signal ratio for the UV-irradiated TiO₂ was significantly higher than that of the non-irradiated TiO₂. UV-irradiated TiO₂ significantly reduced the number of P. gingivalis when compared with non-irradiated controls. These results suggest that TiO₂ has a continuous photocatalytic effect even after stopping UV irradiation and that it showed antimicrobial activity against periodontal pathogen.