Caries Prevention with Silver Diamine Fluoride Studied Under pH-cycling Conditions

Objectives: Silver diamine fluoride (SDF) has been effectively used to arrest active carious lesions. This study investigated the ability of SDF, and its individual components, silver and fluoride ions, in preventing enamel demineralization under pH cycling conditions in the presence or absence of twice-daily fluoride application.
Methods: Polished human enamel specimens were assigned to five treatment groups (n=36 per group) after baseline assessment of sound enamel Vickers surface microhardness (VHN): 38% SDF (253,900 ppm Ag; 44,800 ppm F); 38% SDF followed by supersaturated KI application (SDF+KI); 42% AgNO₃ (silver control; 253,900 ppm Ag); KF (fluoride control; 44,800 ppm F); and deionized water (DIW; negative control). Treatments were applied once. Specimens in each treatment group were divided into two subgroups (n=18). During the subsequent 7-day pH cycling phase, specimens were treated twice daily with either 275 ppm fluoride as sodium fluoride or DIW, immediately before and after a 3-h cariogenic challenge with lactic acid solution and exposure to artificial saliva at all other times. VHN was determined again and changes from baseline calculated (DeltaVHN). Data were analyzed using ANOVA.
Results: DeltaVHN values for pH cycling with fluoride (mean±standard deviation) were: SDF (-61±9); SDF+KI (-61±15); KF (-62±11); AgNO₃ (-77±11); DIW (-77±4). DeltaVHN values for pH cycling with DIW were: SDF (-71±7); SDF+KI (-74±8); KF (-60±12); AgNO₃ (-83±2); DIW (-84±2). In both models, SDF, SDF+KI and KF were more effective in preventing demineralization than AgNO₃ and DIW. There was no difference between SDF, SDF+KI and KF with twice daily fluoride treatments. However, KF was more effective in preventing demineralization than SDF and SDF+KI in the absence of fluoride treatments. KI did not affect the ability of SDF to prevent demineralization and was able to lessen the staining caused by SDF.
Conclusions: SDF and SDF+KI may be viable options in preventing primary coronal caries.