Cytotoxic Effects of Silver Diamine Fluoride

Objectives: Cariogenic bacteria are responsible for the most common chronic disease affecting children in the US and around the world. For decades Silver Diamine Fluoride (SDF) has been used to arrest the caries process and has been touted for its cariostatic and antibacterial properties. The goal of this in vitro study is to investigate the effect of commercially available cariostatic agents on the survival of human gingival fibroblasts.
Methods: Human gingival fibroblasts were allowed to adhere to multi-well plates for 24 hours. Cells were exposed to various dilutions of SDF (Advantage Arrest™) in physiologic saline for two minutes, after which cells were rinsed and cell viability was assessed using Calcein AM and quantified using BioTek Synergy2 fluorescent multi-well plate reader.

In addition, commercially available hydroxyapatite (HA) discs treated with 38% SDF, a 2.5% Sodium Fluoride Varnish (SFV) (FluoriMax™), or saline and allowed to air-dry (per manufacturers instructions). The treated discs were then placed in wells containing gingival fibroblasts for 24 hours. Discs were removed, cells were rinsed, and cell viability was assessed by fluorometrically. Subsequently, control, SDF and SFV treated discs were rinsed for up to 49 days, added to gingival fibroblasts, and cell viability was assessed.
Results: In concentrations as low as 0.02%, SDF was almost 100% cytotoxic to fibroblasts. When applied to HA discs, SDF and SFV induced near-complete cell death after 24 hours. After rinsing SFV discs for 21 days, cell survival exceeded 95%. SDF treated discs retained high levels of toxicity after 49 days of rinsing.
Conclusions: The results of this in vitro study indicate that SDF and SFV can induce gingival cell death. Within three weeks, SFV lost its cytotoxicity, while SDF remained cytotoxic even after nine weeks of rinsing.