Antibacterial effects of mouth moisturizer containing chlorine dioxide

Objectives: Chlorine dioxide (ClO₂) is widely used for biomedical applications, such as mouthwash, because of its antibacterial efficacy. Cellulose gum (CG) is a material that possesses moisturizing effect. In this study, we examined antibacterial effects of mouth moisturizer (ClO₂-CG-Gel) which containing ClO₂ and CG against oral bacteria and duration of the effect. Materials and methods: Twelve species of bacteria used in this study were as follows; S. aureus, C. albicans, S. mutans, S. gordonii, L. casei, A. viscosus, E. coli, P. gingivalis, P. niglescens, F. nucleatum, A. actinomycetmcomitans and V. pervula. The antibacterial effects were measured by disk diffusion test and MIC assay. Disk diffusion test was performed by 5mm of filter paper applied 15ul of 4 kinds of mouth moisturizer including ClO₂-CG-Gel on BHI agar plate and growth inhibition area was measured after 48 hours of incubation. For MIC assay, bacterial solution was added to BHIY broth containing serial diluted mouth moisturizer (2¹-2¹⁵-fold). To determine duration of antibacterial activity in ClO₂-CG-Gel compared to ClO₂-liquid (without CG), residue of antibacterial material were measured with a liquid flow system. Results: Antibacterial effects of ClO₂-CG-Gel were observed against Gram negative oral bacteria, especially against P. gingivalis and P. niglescens, whereas no effect was detected on Gram positive oral bacteria in disk diffusion test. The MIC of ClO₂-CG-Gel for oral bacteria was ranged 2 to 16. The duration of antibacterial effects of ClO₂-liquid continued until 30 minutes, in contrast, antibacterial activity of ClO₂-CG-Gel was sustained after 60 minutes. Conclusion: These results suggest that ClO₂-CG-Gel may contribute to prevent disease of oral cavity.