Silver diamine fluoride in preventing enamel erosion: An in vitro study with salivary pellicle

Objectives: To compare the prevention of enamel erosion and discolouring effect with a single and two weekly topical applications of silver diamine fluoride (SDF) solution.

Methods: Human enamel blocks were divided into four groups. Group 1 (SDF2) received two weekly applications of SDF solution (Advantage Arrest: 260,000 ppm Ag, 44,300 ppm F, pH 9.1). Group 2 (SDF1) received a single application of SDF solution. Group 3 (SNF, Positive Control) received daily application of stannous-chloride/amine-fluoride/sodium-fluoride solution (Elmex® Enamel professional: 800 ppm Sn(II), 500 ppm F, pH 4.5). Group 4 (DW, Negative Control) received daily application of deionised water. The treated blocks were subjected to a 14-day erosive challenge. Crystal characteristics, elemental composition, surface morphology, percentage of surface microhardness loss (%SMHL), surface loss, and total colour change (ΔE) of the blocks were investigated using X-ray diffraction (XRD), energy-dispersive spectrometry (EDS) and scanning electron microscopy (SEM), Vickers' hardness testing, non-contact profilometry, and digital spectrophotometry, respectively.

Results: XRD and EDS revealed precipitates of silver for SDF2 and SDF1 and tin for SNF. SEM showed prominent etched enamel pattern on DW than the other three groups. The%SMHL (%) of SDF2, SDF1, SNF, and DW were 26.6 ± 2.9, 33.6 ± 2.8, 38.9 ± 2.9, and 50.5 ± 2.8 (SDF2<SDF1<SNF<DW, p < 0.001). Surface loss (μm) of SDF2, SDF1, SNF, and DW were 3.1 ± 0.6, 3.9 ± 0.6, 3.9 ± 0.7, and 5.5 ± 0.8 (SDF2<SDF1=SNF<DW, p < 0.05). Colour change of SDF2, SDF1, SNF, and DW were 7.9 ± 3.9, 4.0 ± 3.6, 3.6 ± 3.5, and -4.4 ± 3.9 (SDF2>SDF1=SNF>DW, p < 0.05).

Conclusion: Two weekly applications was more effective than a single application of SDF in preventing enamel erosion, though it caused more discolouration.

Clinical significance: Topical application of 38 % SDF with two weekly applications protocol is effective in preventing enamel erosion.