The Effect of Silver Diamine Fluoride Versus Sodium Fluoride Varnish on the Microhardness of Demineralized Enamel: An In Vitro Study

Background: Fixed orthodontic treatment has been associated with certain side effects such as white spot lesions (WSLs). Many studies showed the positive effect of sodium fluoride (NaF) varnish in remineralizing WSLs. Studies revealed that silver diamine fluoride (SDF) is effective in arresting dentin caries, but its potential for enamel remineralization has not been investigated clearly. The present study aimed to compare the effect of SDF and NaF on the microhardness of demineralized enamel. Methods: A total of 60 intact premolar teeth were collected and divided into 4 equal groups. Group 1 remained intact (control). Groups 2 to 4 were exposed to artificial cariogenic solution to create enamel lesion. Then, groups 3 and 4 were treated with NaF 5% and SDF 38%, respectively. After one month of storage in artificial saliva, NaF and SDF were reapplied. One month later, the surface microhardness values (SMHs) of teeth were assessed. Results: The results of ANOVA showed a significant difference among the 4 groups (P<0.001). There was significantly higher enamel microhardness in the control group compared with groups 2 and 3 (P<0.001); however, it was not significant for the SDF group (P=0.160). There was significantly higher enamel surface microhardness in groups 3 and 4 compared with group 2 (P≤0.001) and significantly higher mean SMH values in the SDF group compared with the NaF group (P=0.004). Conclusions: NaF varnish and SDF can both remineralize early enamel lesion but SDF has greater remineralizing potential.