Dental fillings are often made from mercury and other metals. These are known as amalgam fillings.
Removing amalgam fillings could expose you to mercury vapour, and might weaken the tooth.
If you do have fillings removed, for whatever reason, ask the dentist to explain about any costs and risks. They can also explain how they’ll carry out the procedure (for example, using a rubber dam and suction to minimise exposure to mercury).
Dentists should also be happy to talk about alternatives to amalgam for any new fillings you need – though these might be more expensive and might not be available on the NHS. Find out more about amalgam fillings from the Oral Health Foundation.