Abstract
Objective: In our rapidly aging society, the prevention and treatment of oral mucosal disease is increasingly important. Diseases such as mycotic stomatitis, a mucosal disease with an increased incidence in the elderly, are of particular significance to dentistry because of the risk of fatal aspiration pneumonia in immunocompromised patients or patients with underlying disease. We have synthesized a silane coupling agent having a quaternary ammonium salt group (N-allyl-N-decyl-N-methyl-N-trimethoxysilylpropylammonium iodide or 10-I) with the aim of conferring antimicrobial properties to the surface of dental materials. The aim of this study was to investigate the antibacterial activity and minimum inhibitory concentration of this compound against oral microorganisms. Materials and methods: 10-I was added to brain heart infusion agar and blood agar at concentrations of 100, 200, 400, 600 and 800 ppm. Each plate was inoculated with a 10μl suspension of microorganisms. The lowest concentration of 10-I to inhibit growth of the microorganisms was recorded as the minimum inhibitory concentration. To test the antibacterial activity of the 10-I treated surface against Candida albicans, solutions were prepared containing 6.2×107, 1.1×105, or 1.1×104 CFU/ml of C. albicans. Four ml of each bacterial solution was added to glass plates treated with 400 ppm of 10-I, and then cultured aerobically for 24 hours at 37℃ under shaking conditions. After incubation, the antibacterial activity was measured by counting bacteria on each plate and comparing the decrease in bacterial count between the control plates and experimental plates. Results: The minimum inhibitory concentration of Actinomyces viscosus, Fusobacterium nucleatum, Lactobacillus casei, Porphyromonas gingivalis, and Prevotella intermedia was 200 ppm, and for C. albicans, Staphylococcus aureus, and Streptococcus mutans, the minimum inhibitory concentration was 400 ppm. The antimicrobial activity of the 10-I modified surface against C. albicans decreased by 92.5% at 1.1×104 CFU/ml. Conclusions: The compound 10-I exhibited antimicrobial activity against C. albicans and all oral bacteria tested. This suggests that surface treatment with 10-I could be an effective means of decreasing the incidence in elderly and immunocompromised patients of systemic diseases such as aspiration pneumonia as well as dental diseases caused by specific bacteria found in the oral cavity.
