Salivary and blood silver concentrations following topical 38% silver diamine fluoride application in preschool children: a prospective single-arm repeated-measures study

PURPOSE: To evaluate salivary and blood silver levels following topical application of 38% Silver Diamine Fluoride (SDF) solution in children aged 2-6 years. METHODS: This prospective single-arm repeated-measures study included 20 children aged 2-6 years requiring SDF application. Saliva and blood samples were collected at three time points: baseline (prior to SDF application), 4 h and 1-month post-application. Silver concentrations were expressed in parts per billion (ppb) and quantified using inductively coupled plasma mass spectrometry (ICP-MS). RESULTS: Twenty children were included, with a median age of 4.0 years (IQR 3.38-5.00) and median body weight of 16.0 kg (IQR 14.75-17.70). Median whole-blood silver concentration increased from below the limit of detection at baseline to 15.36 ppb (IQR 8.61-23.50) at 4 h and declined to 2.58 ppb (IQR 1.75-3.68) at 1 month. Median salivary silver concentration increased from 2.57 ppb (IQR 1.57-6.00) at baseline to 197.13 ppb (IQR 111.44-244.76) at 4 h and declined to 3.63 ppb (IQR 2.78-7.72) at 1 month. Overall, silver concentrations differed significantly across time points for both blood and saliva (Friedman test, p < 0.001 for each). A moderate negative correlation was observed between age and the change in whole-blood silver concentration from baseline to 4 h (Spearman's ρ = -0.478, p = 0.033). No treatment-related discomfort or gingival or mucosal adverse effects were observed during follow-up. CONCLUSION: Topical application of 38% SDF in preschool children resulted in a transient increase in salivary and blood silver concentrations, followed by a marked decline in measured concentrations by 1 month. These findings provide short-term exposure data following a single SDF application; however, the observed decline should not be interpreted as evidence of complete systemic clearance, absence of tissue accumulation, or long-term systemic safety.