An amalgam filling is a metal dental filling that was previously used especially for chewing teeth. It consists of an alloy of metals, typically silver tin copper and mercury. Mercury makes up a significant portion of the material and binds the other metals into a strong mass. The main thing that often raises questions is this: yes amalgam does contain mercury. Fillings can indeed release small amounts of mercury vapor especially during chewing and bruxism. But this doesn't mean every old amalgam filling needs to be removed immediately. Removing it can even temporarily increase mercury exposure which is why intact and functioning fillings are usually not removed solely because they are amalgam. Nowadays the use of amalgam in many countries is being severely limited or gradually phased out and composites and other modern materials are increasingly used instead.