Antibacterial effect of synthetic dental resin containing TiO₂ microparticles

Abstract

Antibacterial, antiviral and antimycotic activities of the photocatalytic semiconductor TiO2 have been demonstrated in recent years. The purpose of this study was to determine the antibacterial properties against bacteria in saliva of a synthetic dental filling resin containing TiO2. The test material contained anatase TiO2 microparticles that had been irradiated under light from a light-emitting diode for 2 h in saline. The material was then embedded in a mouthpiece and set in an oral cavity for 30 min. It was removed and washed in saline, and a bacterial suspension was collected from the wash solution and inoculated in fixed amounts onto blood agar plates that were then incubated anaerobically for 48 h. The bacterial counts were then calculated from photographic images of the plates. The packing density of viable bacteria on the plates (the percentage occupied by bacterial colonies) was found to be 16.3-87.6% without TiO2, and 0.5-24.1% with TiO2. The viable bacteria on the plates were 191-506×108 colony-forming units per milliliter (CFU/mL) in the non-TiO2 group, and 1-74×108 CFU/mL in the TiO2 group. Significant differences were seen between the two groups (p<0.01) for both packing density and viable cell counts. The results showed that light irradiation of the synthetic preventive dental filling resin containing TiO2 had an antibacterial effect on whole saliva. (J Osaka Dent Univ 2023; 57: 83-88)