Preventing Dentine Collagen Degradation by Silver Nitrate and Sodium Fluoride

Objectives: To investigate the effectiveness of 25% silver nitrate solution (AgNO₃) and 5% sodium fluoride (NaF) varnish in preventing dentine collagen degradation of demineralized dentine.
Methods: Human dentine slides were prepared and demineralized with acetic acid for 96 hours. Each slide was cut into 3 specimens for 3 groups (SF, SDF and W). Specimens of the SF group received topical application of 25% AgNO₃ solution followed by 5% NaF varnish. SDF group received a topical application of 38% silver diamine fluoride (SDF) solution (positive control). Specimens of the W group received deionized water (negative control). They were subjected to pH cycling using demineralisation solution (pH 5.0) and remineralisation solution (pH 7.0) at 37°C for 8 days. The surface collagen morphology of the blocks, collagen matrix degradation of dentine was investigated by scanning election microscopy (SEM), and spectrophotometry at 550 nm with a hydroxyproline assay.
Results: SEM showed that dentine collagen was exposed in group W, but not in groups SF and SDF, clusters of granular spherical grains were observed in groups SF and SDF. The concentration of hydroxyproline (±SD) in the remineralisation solution was 312±11 µg/mL, 317±16 µg/mL and 339±16 µg/mL in group SF, SDF and W, respectively (SF, SDFConclusions: In this in vitro study, treatment of 25% AgNO₃ solution followed by 5% NaF varnish was effective in preventing dentine collagen degradation in demineralized dentine.