Silver has been shown to be biocompatible and is used for a range of medical devices
Excess silver accumulates in skin, liver, kidneys, spleen, corneas, gingiva, mucous membranes, nails; In areas of the body exposed to light, prolonged exposure to large amounts of silver compounds results in irreversible pigmentation of the skin- called argyria- or eyes- called argyrosis.
Manufacturer (Saforide) of SDF recommends patient rinse mouth with water or saline after topical application of SDF to remove the excess agent