NANO SILVER FLUORIDE AND ENAMEL REMINERALIZATION: CURRENT EVIDENCE AND TRANSLATIONAL GAPS

Silver diamine fluoride (SDF) is an effective agent for caries management, but the dark staining it produces limits its use, particularly on visible enamel surfaces. Formulations combining silver nanoparticles and fluoride, commonly termed nano silver fluoride (NSF), have been proposed as an aesthetic alternative. This narrative review aimed to synthesize laboratory, in situ and clinical evidence on the remineralizing effect of silver nanoparticle and fluoride formulations on initial enamel caries lesions. A search of PubMed/MEDLINE retrieved 173 records, and 19 studies met the eligibility criteria: 16 laboratory studies, one in situ study and two randomized clinical trials. In laboratory models, these formulations promoted enamel remineralization and prevented demineralization to an extent generally comparable to sodium fluoride agents, whereas comparisons with SDF were inconsistent, ranging from equivalent to inferior performance. The only in situ study found that an experimental silver nanoparticle and fluoride solution achieved surface and subsurface mineral recovery similar to SDF. In the two clinical trials on white spot lesions, NSF reduced lesion severity but did not outperform sodium fluoride varnish or nano hydroxyapatite. All studies assessing color reported minimal or imperceptible staining, in contrast with SDF. Interpretation is limited by marked heterogeneity in formulation composition, substrates, cariogenic challenge models and outcome measures, as well as by small sample sizes and incomplete reporting of nanoparticle characteristics. Silver nanoparticle and fluoride formulations are a promising esthetic option for managing initial enamel lesions, but standardized formulations and adequately powered clinical trials with long term follow up are needed before they can be recommended as a replacement for established remineralizing agents.