Anti-erosive effect of silver diamine fluoride against enamel erosion: An in situ study

To investigate anti-erosive effect of silver diamine fluoride (SDF) against enamel erosion and assessed associated color change.

This three-phase crossover in situ study compared anti-erosive effect of SDF and stannous chloride/amine fluoride/sodium fluoride mouthrinse (SNF) against distilled water (DW, control), while evaluating enamel color changes. Fifteen adults (27-35 years) wore palatal appliances with four-enamel blocks per phase, alternating 14-day intervention periods (weekly 38% SDF [255,000 ppm Ag, 44,800 ppm F], daily SNF mouthrinse [800 ppm Sn, 500 ppm F], or weekly DW) separated by 7-day washouts. Appliances were exposed with five 2 min extraoral erosive challenges (citric acid, pH 3.2) daily. Post-intervention analyses included salivary pellicle morphology (atomic force microscopy, AFM), enamel surface integrity (scanning electron microscopy, SEM), elemental composition (energy-dispersive X-ray spectroscopy, EDS), crystal structure (X-ray diffraction, XRD), surface microhardness loss (hardness tester), surface loss (optical profilometry), and color change (spectrophotometry).

AFM revealed altered pellicle morphology in SDF and SNF groups. SEM demonstrated reduced enamel erosion in SDF and SNF versus DW. EDS confirmed Ag⁺ deposition in SDF and Sn²⁺ in SNF. XRD identified fluorapatite in SDF and SNF groups. SDF showed the lowest surface microhardness loss (21.7±1.0%) and surface loss (µm) (2.7±0.6), followed by SNF (30.0±1.1%; 3.2±0.7), and DW (42.4±1.0%; 5.4±0.8) (p<0.001). However, SDF caused greatest color change (ΔE₀₀=6.6±2.1), followed by SNF (ΔE₀₀=5.8±1.0), and DW (ΔE₀₀=3.6±1.7) (p<0.001).

Weekly SDF application demonstrated superior erosion resistance compared to daily SNF, likely attributed to silver-fluoride-induced fluorapatite crystallization and pellicle structural reinforcement. However, enamel staining is an esthetic trade-off.