Oral Health and Dental Management

Abstract

Effects of Storage Temperatures and Type of Oral Moisturizers on their Antifungal Effects

Mamoru Murakami, Kei Fujishima, Yasuhiro Nishi, Kae Harada, Masahiro Nishimura

Purpose: This study aimed to examine the effect of storage temperature and oral moisturizer type on antifungal effects. Materials and Methods: Three oral moisturizers (two liquids and one gel), mixtures of the three moisturizers, and amphotericin B were tested. Antifungal effects were evaluated with moisturizer samples stored at 37°C, 25°C, and 4°C. Candida albicans (107 cells/ml) was mixed with trypticase soy agar medium and inoculated on 50% trypticase soy agar plates. Oral moisturizer samples were placed in cylindrical holes in the plates, and antifungal effects were evaluated based on growth-inhibitory zones after 24 hours. The effects of storage temperature and type of moisturizer on the growth-inhibitory zones were evaluated with analysis of variance. Growthinhibitory zone sizes were compared with multiple comparisons. Results: Growth-inhibitory zones were formed with all moisturizer samples and amphotericin B. Significant differences in antifungal effects were found among the different storage temperatures and moisturizer types. The growth-inhibitory zones of the moisturizer samples stored at 4°C were significantly smaller than those of samples stored at other temperatures. Under the same temperature conditions, the growth-inhibitory zones of liquid-gel mixtures were significantly larger than those of other moisturizer types. The zones of the liquid-gel mixtures stored at 37°C were significantly larger than that of high concentrations of amphotericin B (0.63 µg/ml). However, the growth-inhibitory zones of almost all moisturizers were similar in size to that of low concentrations of amphotericin B (concentration, 0.04 µg/ml) at 4°C. Conclusion: From the viewpoint of the antifungal effect, our findings suggest that oral moisturizers should not be stored at low temperature.