You or your dentist may notice a gray, blue or black spot in your mouth that looks like a tattoo. Dentists call these spots amalgam tattoos. They can appear in the mouth of someone with amalgam fillings or metal false teeth (also known as “caps” or “crowns”). Amalgam tattoos are made up of tiny metal particles from the filling or crown that become embedded in the tissue. They can appear on your gums, cheek, lips, tongue or the roof of the mouth (palate). The tattoos are flat and usually quite small and relatively easy to see. 
Amalgam tattoos are quite common, although many people don’t even know they have them. These tattoos are not dangerous and will not cause you harm but getting them removed is advised to bring back the normal colour of the tissues.
