In Vitro Silver and Fluoride Release from Silver Diammine Fluoride-Treated Caries Lesions

Purpose: The purpose of this in vitro study was to investigate the release of silver and fluoride ions from caries lesions treated with silver diammine fluoride (SDF), with and without using a light-emitting diode (LED) curing light, the use of which increases silver penetration into the lesion. Methods: Eighteen extracted primary molars with natural caries lesions were divided into four groups: (1) one-minute SDF (n equals six); (2) 40-second SDF + 20-second LED (n equals six); (3) untreated control (n equals three); and (4) 20-second LED control (n equals three). Samples were immersed in artificial saliva for 0.5 hours, one hour, 24 hours, and one, two, and four weeks. Silver and fluoride concentra- tions were analyzed using si-ICP-MS and F-ISE, respectively. Statistical analyses were done using the Mann-Whitney U-test and Wilcoxon signed rank exact test. Results: At 0.5 hours, mean and median concentrations of silver and fluoride in Group 1 were statistically higher than those in Group 2 (P=0.015 for silver and P=0.026 for fluoride), and significantly higher than the rest of the time points (P=0.03 for all comparisons). Groups 3 and 4 had no detectable amounts of silver or fluoride. Conclusions: Applying a light-emitting diode light after silver diammine fluoride appli- cation leads to a substantial reduction in the release of silver and fluoride into the surrounding medium compared to a one-minute SDF application after 0.5 hours. These in vitro findings, while statistically significant, indicate a trend that requires further investigation to assess clinical relevance.