RESUMO
OBJECTIVES: The main goal of this study was to investigate the effectiveness of SDF and its individual components, silver (Ag+) and fluoride (F-) ions, in preventing enamel demineralization using biofilm and chemical models. METHODES: Polished human enamel specimens were assigned to five treatment groups (nâ¯=â¯18 per group): SDF (38 %); SDF followed by application of a saturated solution of potassium iodide (SDFâ¯+â¯KI); silver nitrate (AgNO3; silver control, 253,900â¯ppm Ag+); potassium fluoride (KF; fluoride control, 44,800â¯ppm F); deionized water (DIW). Treatments were applied once to sound enamel. In the biofilm model, specimens were demineralized by aerobic overnight incubation using cariogenic bacteria isolated from human saliva in brain heart infusion supplemented with 0.2 % sucrose for three days. In the chemical model, enamel specimens were immersed in a demineralizing solution containing 0.1â¯M lactic acid, 4.1â¯mM CaCl2, 8.0â¯mM KH2PO4, 0.2 % Carbopol 907, pH adjusted to 5.0 for five days. Vickers surface microhardness was used to determine the extent of enamel demineralization. Data were analyzed using one-way ANOVA. RESULTS: In the chemical model, there was no statistically significant difference between SDF and SDFâ¯+â¯KI in preventing coronal caries (pâ¯<â¯0.0001). In the biofilm model, SDFâ¯+â¯KI was significantly less effective in preventing demineralization than SDF (pâ¯<â¯0.0001). In both models, SDF and SDFâ¯+â¯KI were superior in their ability to prevent caries lesion formation than AgNO3 and DIW. CONCLUSION: KI application after SDF treatment appears to impair SDF's ability to prevent biofilm-mediated but not chemically induced demineralization. CLINICAL SIGNIFICANCE: SDF may be a viable option in preventing primary coronal caries.