Mercury fillings: symptoms, side effects and whether to remove them

What a mercury filling actually is

A "silver filling" is dental amalgam. According to the U.S. Food and Drug Administration (FDA), it is a mixture of mercury, silver, copper, tin and zinc, and it is about half mercury by weight. Amalgam has been used for well over a century because it is strong, inexpensive and forgiving to place, which is why so many adults still have several.

The mercury is bound into the filling, but not completely locked away. The FDA notes that amalgam can release small amounts of mercury as vapour, depending on how many fillings you have, how old they are, and habits such as grinding your teeth or chewing gum. Placing or removing an amalgam filling causes a temporary increase in exposure for the patient and the dental team.

Do mercury fillings cause symptoms?

This is the question most people are really asking, so here is the honest answer from the FDA's own patient guidance.

People with several amalgam fillings may have slightly higher mercury levels in their blood or urine, but those levels usually remain in a range considered safe. Studies have not shown conclusive evidence that amalgam causes harmful health effects in the general population.

The FDA also lists signs and symptoms of excessive mercury in the body: mood changes such as anxiety, depression or irritability, sleep problems, fatigue, memory problems, tremors, difficulty with coordination, and changes in vision or hearing. It is careful to add that a direct link between mercury from fillings and these effects has not been established, and that mercury also comes from other sources such as diet and the environment.

So there is no reliable symptom checklist that can tell you your fillings are the cause of how you feel. Symptoms like these deserve a proper medical workup, and your fillings are one part of a bigger picture rather than the automatic answer.

Allergy and sensitivity

A smaller group of people have a true allergy or sensitivity to mercury or to another component of amalgam. The FDA notes these patients may report allergic reactions and oral ulcers, as well as more general symptoms, after an amalgam filling is placed. If you have a known metal allergy, tell your dentist before any new filling.

Who should be more careful

In 2020 the FDA identified groups who may be more susceptible to mercury from amalgam, and recommended they avoid new amalgam fillings where possible and appropriate:

• People who are pregnant or planning a pregnancy
• Nursing mothers
• Children, especially those under six
• People with a known allergy or sensitivity to mercury or other amalgam components
• People with neurological impairment or kidney dysfunction

The FDA is clear that this guidance is about new fillings. It does not recommend removing sound fillings in these groups just to prevent illness.

How to tell if a filling contains mercury

Amalgam is easy to spot once you know what to look for:

• Colour. Silver or dark grey, often darkening with age. Tooth coloured fillings are composite or ceramic, and gold fillings look gold.
• Age. Fillings placed decades ago, especially on back teeth, are often amalgam.
• On an x-ray. Amalgam shows up bright white because it blocks x-rays.

Your dentist can confirm in a few seconds at an exam.

Should you get your mercury fillings removed?

Not automatically. The FDA does not recommend removing a filling that is in good condition with no decay underneath, because removal briefly raises mercury exposure and always takes some healthy tooth with it. The American Dental Association holds the same view on intact fillings.

There are good reasons to replace an amalgam filling, though:

• It is cracked, leaking or worn down
• There is decay underneath it
• The tooth around it is fracturing
• You have a known sensitivity, or a health condition your physician wants taken into account

When a filling does come out, the method matters. The SMART protocol published by the International Academy of Oral Medicine and Toxicology is designed to reduce exposure: the tooth is isolated with a rubber dam, high volume suction captures vapour and particles at the source, you breathe from a separate air supply, everyone is protected, and the filling is cut into pieces and lifted out rather than ground into dust. The FDA advises that if you are concerned about mercury, resin based materials should be strongly considered for the replacement.

If you are pregnant or nursing, talk to your dentist and your physician first. Removal itself causes a short spike in exposure, so timing matters.

Can you get an MRI with mercury fillings?

Generally, yes. Amalgam is not magnetic in the way that iron or steel is, and it is regarded as compatible with MRI at the field strengths used for most clinical scans. Metal fillings can distort images of the face and jaw, so tell your radiology team. Small laboratory studies at very high field strengths have reported some release of mercury from amalgam, but that has not been shown to be a clinical risk with standard scanners.

When did dentists stop using mercury fillings?

It depends where you live. In the United States amalgam is still legal, although its use has been declining for years in favour of tooth coloured materials. The European Union stopped its routine use from 1 January 2025, allowing it only where a dentist judges it strictly necessary for a patient. In November 2025 the parties to the Minamata Convention on Mercury agreed a global phase out of dental amalgam by 2034, with a similar clinical exception.

None of these rules require removing fillings that are working. They are about what goes into mouths from now on.

How we handle amalgam

Dr. Panahpour is SMART certified and an accredited member of the IAOMT, and every amalgam filling in his practice comes out under the same protocol. The first step is always an honest look at each filling, including the ones that are better left where they are.