Comparative Evaluation of Surface Microhardness and Antibacterial Efficacy of Phosphorylated Chitosan, Silver Diamine Fluoride, and Sodium Fluoride Varnish: An In-Vitro Study

Abstract

Background: Dental caries involves enamel mineral loss and cariogenic bacterial activity. Materials with both remineralizing and antibacterial properties may improve preventive care.
Aim: To compare phosphorylated chitosan (PCh), silver diamine fluoride (SDF), and sodium fluoride (NaF) varnish for enamel surface microhardness and antibacterial activity against Streptococcus mutans.
Materials and Methods: Forty sound extracted permanent teeth were divided equally into PCh, SDF, NaF varnish, and distilled-water groups. Vickers microhardness was measured at baseline, after demineralization, and after treatment. Antibacterial activity was assessed using agar-well diffusion with 10 observations per group. Data were analyzed using SPSS version 23.0. One-way ANOVA was used for intergroup comparisons, followed by post hoc analysis. Statistical significance was set at p < 0.05.
Results: Microhardness increased significantly with PCh, SDF, and NaF varnish (p = 0.001 each), but not with distilled water (p = 0.923). Percentage increases were 4.26%, 5.66%, and 6.05%, respectively, without a significant overall intergroup difference (p = 0.552). SDF showed the highest inhibition zone (15.95 ± 1.59 mm), followed by PCh (14.45 ± 1.91 mm) and NaF varnish (8.97 ± 4.38 mm). The antibacterial difference was significant (p < 0.001).
Conclusion: PCh showed promising combined remineralizing and antibacterial properties, warranting further clinical investigation.