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What are NHS fillings and crowns made of?

Fillings and crowns available on the NHS can be made of several different materials.


Fillings are used to repair a cavity in your tooth caused by decay. Your dentist will offer you the type of filling they consider clinically necessary.

The most common type of filling is dental amalgam, made from a mixture of different metals. Dental amalgam fillings are often used on your back teeth as they're hard-wearing.

If you need a filling for one of your front teeth, your dentist may suggest a tooth-coloured (white) filling.

Fillings available on the NHS can be made of:

  • amalgam (silver-coloured) – a mixture of metals, including mercury, silver, tin and copper
  • composite (tooth-coloured) – made of resin and glass mixture
  • glass ionomer (tooth-coloured) – powdered glass, which forms a chemical bond with your tooth and may release fluoride that helps to prevent further decay

Although amalgam fillings can release low levels of mercury vapour, particularly when they are put in or removed, there is no evidence that exposure to mercury from amalgam fillings has any harmful effects on health.

Talk to your dentist if you have any concerns.


A crown is a type of cap that completely covers a real tooth.

Crowns available on the NHS can be:

  • all metal (such as gold or another alloy)
  • porcelain fused to metal
  • all resin
  • all ceramic
  • stainless steel – used to preserve badly decayed baby teeth in children, or as a temporary measure on permanent teeth

Your dentist will offer you the type of crown they consider clinically necessary.

Further information

Page last reviewed: 14 November 2023
Next review due: 14 November 2026