Antimicrobial effects on streptococcus mutans and candida albicans and cytotoxicity study on human periodontal ligament fibroblast cell line of oxy-ionic solution at various ph levels - an in vitro study

• Main Author: Ming, Xu
• Format: Thesis
• Language: English
• Published: 2025
• Subjects: R Medicine; RA Public aspects of medicine
• Online Access: http://eprints.usm.my/62844/

Oxy-ionic solutions, comprising hypochlorous acid, sodium hydroxide, and active chlorine, have gained recognition in dental care for their strong antimicrobial properties, especially against pathogens like Streptococcus mutans and Candida albicans. These solutions are produced through the electrolysis of saline water. However, the influence of pH on their antimicrobial effectiveness and cytotoxicity remains uncertain. This study investigates the antimicrobial efficacy of oxy-ionic solutions at varying pH levels (3, 5, and 7) against Streptococcus mutans and Candida albicans and their cytotoxicity on human periodontal ligament fibroblasts. This study evaluated the antimicrobial efficacy and cytotoxicity of oxy-ionic solutions using three complementary approaches. First, disk diffusion and broth microdilution assays quantified antimicrobial effects. Second, scanning electron microscopy (SEM) revealed microbial morphological changes. Third, ATP assays determined cytotoxicity against human periodontal ligament fibroblasts. The oxy-ionic solutions were tested at pH 3, 5, and 7 with concentrations of 100%, 75%, and 25%, except for pH 7 which was assessed only at 100% concentration. Disk diffusion results revealed that the pH 5 solution exhibited the largest zones of growth inhibition, with diameters of 13.79 mm for Streptococcus mutans and 19.67 mm for Candida albicans, indicating the strongest antimicrobial efficacy among the tested pH levels. Broth microdilution assays further confirmed this, with the pH 5 solution demonstrating the minimum inhibitory concentration of 50% for Streptococcus mutans and 25% for Candida albicans. Scanning electron microscopy analysis showed significant microbial cell wall damage and morphological changes when treated with the pH 5 solution. The ATP assay results on human periodontal ligament fibroblasts showed that all concentrations of oxy-ionic solutions at pH 3, pH 5, and pH 7 exhibited significant cytotoxicity after 2 minutes of exposure. Although cell viability improved with extended exposure time to 24 hours, it still remained below safe thresholds. These findings suggest that there is a therapeutic potential in the dental care of oxy-ionic solution pH 5 based on high antimicrobial effects, however further study on the dilution of the solution is necessary to ensure clinical safety and effectiveness.