Antimicrobial effects of silver diamine fluoride: An in vivo study

To compare the antimicrobial effect of treating dentin caries lesions with silver diamine fluoride (SDF) in different concentrations and chlorhexidine (CHX).

Children aged 7-10 years presenting one occlusal dentin carious lesion in primary molars were selected, totaling 40 teeth. The sample was randomly divided into four groups: (G1) 38%-SDF + potassium iodide (KI); (G2) 30%-SDF; (G3) 2%-CHX; and (G4) control group. After cleaning the cavity up to firm dentin, a sample of dentin from the pulp wall was collected; the cavity was then treated with the antimicrobial agent tested and, immediately after, another dentin sample was collected. Cavities were restored with high viscosity glass ionomer cement. Microorganisms were counted, and species from the Streptococcus genus were analyzed for susceptibility to antimicrobial agents. Shapiro-Wilk and Levene's tests were used to assess normality and homogeneity, respectively. Student's t-test, two-way ANOVA, and Bonferroni post-test were applied for multiple comparisons.

For the overall microorganisms count, it was observed that G1 and G2 presented a statistically lower number of microorganisms following treatment in comparison to G3 and G4 (P< 0.05). When analyzing the Streptococcus spp. and Enterococcus sp. separately, a statistical reduction in the microorganism count before and after the treatment was observed for all groups (P< 0.05), excluding the control group. Among the species tested, S. mutans were the least susceptible to SDF treatments compared to the other species. The treatments with SDF were more effective in reducing microorganisms when compared to CHX. Similarly, the susceptibility of Streptococcus to CHX was lower than that observed for SDF.

In cases where the dental professional decides to apply an antimicrobial agent prior to the placement of a restoration, silver diamine fluoride proved to be more effective than chlorhexidine, slowing the progression of carious lesions, and possibly preventing future restorative interventions thus improving children's quality of life. It is important to note that clinicians should consider the type of restorative material that will be used due to the possibility that the use of SDF may influence adhesion of the subsequent restoration.