The effectiveness of silver diamine fluoride on remineralisation/ demineralisation of artificially demineralised enamel and dentine lesions in vitro

To investigate the effect of Silver Diamine Fluoride (SDF), SDF with potassium iodide (SDF/KI) and Fluoride varnish (FV) on progression/regression of artificially demineralised dentine lesions under PH-cycling regime in vitro. Artificial caries lesions were produced then divided into experimental groups: SDF, SDF/KI, FV, and control. The dentine slabs with artificial lesions were subjected to pH cycling regime. Cross sectional Knoop microhardness (KHN) values were taken before and after treatment. The mean difference within groups was compared using Wilcoxson-Signed Rank test. Kruskal-Wallis Test and posthoc pairwise comparison with Bonferroni correction were used to compare KHN between groups. The KHN of the lesion increases after treatment with SDF, SDF/KI and FV, significant from depths up to 100 µm (p<0.05) whilst no improvement in KHN of W. No significant change in KHN was seen at level 80, 100, and 120µm for all groups except W. The lesions were softer at deeper levels from 120 to 300 µm for all groups when compared to untreated lesions. The mean difference between W and SDF were highly significant at all levels except at 80 and 100. The surface morphology analysis under SEM showed clusters of granular spherical grains occluding the dentinal tubules in group SDF and SDF/KI. Group W showed evident demineralisation with exposed tubules. Elemental analysis confirmed the presence of silver particles and fluoride remains on the lesion surface after acidic challenge. This study showed that SDF has the highest remineralising potential on artificial subsurface dentine lesions after acidic challenge in vitro, followed by SDF/KI then FV. SDF also has the ability to minimise lesion progression significantly in the deeper depths compared to other groups, but only confined to the outer dentine lesion. Despite its limitations, the study certainly adds to our understanding of the mechanism of action of SDF in dentine lesions.