In vitro demineralization prevention by fluoride and silver nanoparticles when applied to sound enamel and enamel caries-like lesions of varying severities.

OBJECTIVES: To investigate the effect of fluoride and silver nanoparticles on the prevention of in vitro demineralization of sound enamel and enamel caries-like lesions of varying severities. METHODS: Caries-like lesions of different severities (1/6/15 days) were created in bovine enamel specimens. One group remained sound. All specimens were demineralized again using a partially saturated acetic acid solution. Mimicking the intra-oral retention of fluoride and silver in vitro, this solution was supplemented with fluoride (0/1/10 ppm) and/or silver nanoparticles (0/10 ppm) in a factorial design. Changes in lesion depth (DeltaL) and integrated mineral loss (DeltaDeltaZ) were evaluated by digital transverse microradiography. Data was analyzed using three-way ANOVA. RESULTS: Lesion severity significantly affected DeltaDeltaZ and DeltaL, after no treatment and after the treatment of fluoride and silver independently (p = 0.012 and p = 0.037, respectively). Fluoride and the fluoride x lesion severity interaction were shown to be significant (p < 0.001) on DeltaDeltaZ and DeltaL. Silver nanoparticles significantly affected DeltaDeltaZ (p = 0.041), but not DeltaL (p = 0.15). The silver nanoparticles x lesion severity interaction was significant for DeltaDeltaZ and DeltaL (p = 0.032 and p = 0.024, respectively). No interaction was observed for DeltaDeltaZ and DeltaL between fluoride and silver (p = 0.962 and p = 0.971, respectively) as well as lesion severity and the use of fluoride and silver combined (p = 0.722 and p = 0.158, respectively). CONCLUSION: Fluoride and silver nanoparticles had a significant effect on the prevention of in vitro demineralization of sound enamel and enamel caries-like lesions of varying severities. CLINICAL SIGNIFICANCE: Fluoride and silver nanoparticles may potentially allow for more tailored caries prevention.