The preventive effect of silver diamine fluoride-modified salivary pellicle on dental erosion

Objective To investigate the preventive effect of silver diamine fluoride (SDF) modified salivary pellicle (SP) against dental erosion. Methods Enamel and dentin blocks allocated into 4 groups (n = 30 each). Blocks in Group SDF+SP were treated with SDF and SP. Blocks in Group SDF were treated with SDF. Blocks in Group DW+SP were treated with deionized water (DW) and SP. Blocks in Group DW were treated with DW. The blocks were subjected to an erosive challenge at pH 3.2 for 2 mins, 5 times per day for 14 days. Salivary pellicle morphology was assessed by atomic force microscopy (AFM). Crystal characteristics, percentage microhardness loss (%SMHL), surface loss, and surface morphology were assessed by X-ray diffraction (XRD), microhardness test, profilometry, and scanning electron microscopy (SEM), respectively. Results AFM revealed a modified pellicle morphology in Group SDF+SP. XRD of both blocks revealed hydroxyapatite, silver chloride, silver phosphate, and silver fluoride in Groups SDF+SP and SDF. Fluoroapatite was found in Group SDF+SP only. %SMHL ( +/- Standard deviation in %) of Groups SDF+SP, SDF, DW+SP, and DW were 33.4 +/- 2.2, 38.6 +/- 2.2, 50.3 +/- 2.2, and 58.3 +/- 2.4 in enamel and 16.1 +/- 2.2, 19.7 +/- 2.1, 32.8 +/- 2.1, and 39.0 +/- 2.3 in dentin, respectively. The presence of SDF and SP reduced %SMHL in both blocks (p < 0.001). The surface loss ( +/- Standard deviation in mu m) of Groups SDF+SP, SDF, DW+SP, and DW were 3.6 +/- 0.7, 4.1 +/- 0.4, 5.3 +/- 0.5, and 7.0 +/- 0.6 in enamel and 5.4 +/- 0.6, 6.1 +/- 0.5, 9.1 +/- 0.7, and 9.2 +/- 0.5 in dentin, respectively. The presence of SDF and SP reduced surface loss in enamel and dentin blocks (p = 0.031 and p = 0.002, respectively). SEM showed enamel surface remained relatively smooth and partially dentinal tubule occlusion on dentin blocks in Groups SDF+SP and SDF. Conclusion SDF had a positively synergistic effect with SP. SDF-modified salivary pellicle provided a superior protective effect against dental erosion.