Preventive Effects of SDF Against Enamel Erosion: an in-Situ Study

Objectives: To evaluate the preventive effect of silver diamine fluoride (SDF) on enamel against dental erosion.
Methods: The randomized, crossover in situ study recruited 12 healthy volunteers aged 25- to 35-year-old without caries and periodontal disease. Each volunteer wore a removable appliance containing four human enamel samples for a 14-day period in each group of treatment. The four enamel in each appliance were subjected to three treatments with a 7-day washout period between treatments: Group1-SDF received a weekly application of 38% SDF, Group2-SNF received a daily application of stannous chloride/amine fluoride/sodium fluoride (standard of care for dental erosion), and Group3-DW received a daily application of deionized water (negative control). After the intervention, each volunteer wore the appliance for one hour before five extra-oral erosive challenges with 0.3% citric acid daily at one-hour interval. The enamel blocks were investigated after 14 days on crystal characteristics, percentage of surface microhardness loss (%SMHL), enamel surface loss, and surface morphology using X-ray diffraction (XRD), hardness testing, non-contact profilometry, and scanning electron microscopy (SEM), respectively. Data were analyzed using one-way ANOVA followed by Tukey’s multiple comparison tests.
Results: XRD of enamel blocks revealed that fluorapatite, silver chloride, silver phosphate, and silver fluoride formed in Group1-SDF, while fluorapatite and stannous oxide formed in Group2-SNF. Group3-DW showed hydroxyapatite and calcium phosphate. %SMHL (%) of Group1-SDF, Group2-SNF, and Group3-DW were 21.7±1.0, 30.0±1.1, and 42.4±1.0, respectively (SDFp<0.001). Enamel surface loss (μm) of Group1-SDF, Group2-SNF, and Group3-DW were 2.7±0.6, 3.2±0.7, and 5.4±0.8, respectively (SDFp<0.05). SEM images showed less enamel demineralization pattern in Group1-SDF and Group2-SNF compared to Group3-DW.
Conclusions: This in situ study found that SDF with weekly applications was significantly more effective than SnCl₂/AmF/NaF in terms of lower %SMHL and less enamel surface loss.