Inhibitory effect of silver diamine fluoride on dentine demineralisation and collagen degradation

Abstract

Objective: To investigate the inhibitory effects of 38% silver diamine fluoride (SDF) on demineralised dentine.

Methods: Human dentine blocks were demineralised and allocated to four groups: SF, F, S and W. The blocks in group SF received a topical application of 38% SDF solution (253,900ppm Ag, 44,800ppm F), group F received a 10% sodium fluoride solution (44,800ppm F), group S received a 42% silver nitrate solution (253,900ppm Ag) and group W received deionised water (control). They were subjected to pH cycling using demineralisation solution (pH 5) and remineralisation solution (pH 7) for 8 days. The surface morphology, crystal characteristics, lesion depth and collagen matrix degradation of the specimens were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-CT testing and spectrophotometry with a hydroxyproline assay.

Results: The surface morphology under SEM showed evident demineralisation with exposed collagen in groups S and W, but not in group SF. Clusters of granular spherical grains were observed in the cross-sections of specimens in groups SF and F. XRD revealed precipitates of silver chloride in groups SF and S. The mean lesion depths (±SD) of groups SF, F, S and W were 182 ± 32μm, 204 ± 26μm, 259 ± 42μm and 265 ± 40μm, respectively (SDF, F<S, W; p<0.01). Groups SF and S had significantly less hydroxyproline liberated from the dentine matrix than groups F and W (p<0.01).

Conclusion: The use of 38% SDF inhibited demineralisation and preserved collagen from degradation in demineralised dentine.

Clinical significance: SDF application positively influences dentine remineralization.

Keywords: Collagen; Demineralisation; Dentine; Hydroxyproline; Remineralisation; Silver diamine fluoride.