Materials
Silver diamine fluoride
Silver diamine fluoride, or SDF, is a liquid a dentist paints on a cavity to help stop decay from growing, and it can leave the spot dark.
SDF is a clear or blue-tinted liquid made of silver, fluoride, and ammonia. A dentist brushes a drop onto a decayed spot. The silver acts against germs and the fluoride helps the tooth harden. It is often discussed for young children and for people with special care needs. The ADA says SDF is cleared by the FDA as a Class II medical device to treat tooth sensitivity, and that its use to arrest cavities is off-label. A common effect is that the treated spot turns dark. It may need to be repeated. Your dentist will talk with you about the choices. See cavity and fluoride varnish.