In-vitro Comparison of Anti-Microbial Efficacy and Enamel Microhardness after Application of Two Types of Fluoride Varnishes

Introduction: Human dental enamel is made of hydroxyapatite crystals and fluorapatite combined with traces of delta calcium metaphosphate. Topical fluoride interacts with saliva and forms Calcium Fluoride (CaF) compounds on enamel which acts as a barrier in demineralisation process of caries formation. Aim: To evaluate and compare the anti-microbial efficacy against S. mutans and enamel surface microhardness after application of two fluoride varnishes containing Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP) and xylitol coated calcium phosphate ions as active ingredients. Materials and Methods: This was an in-vitro study involving one parameter on agar discs and one parameter on human enamel samples from November 2019 to January 2020. The anti-microbial efficacy of MI Varnish (GC Dental) and Embrace Varnish (Pulpdent) was comparatively assessed. Ten wells of each varnish were assessed using disc diffusion method on Trypticase-Yeast-Cysteine-Sucrose-Bacitracin (TYCSB) agar plate. Zone of inhibition around each sample was measured after 48 hours of agar plate anaerobic incubation and the value was recorded using digital Vernier calliper. The change in enamel surface microhardness with and without application of fluoride varnish was assessed using Vickers Microhardness method on 30 samples. The results were compiled and compared using ANOVA. Results: MI Varnish showed the higher antibacterial effects, compared to Pulpdent Embrace Varnish against S. mutans (p