Mercury fillings and holistic dentistry

A dental practice may describe itself as holistic, biological, environmental or mercury-free. Most people who look into what that means arrive with one narrow question: whether the amalgam fillings already in their mouth ought to come out.

That question has a clear answer, and it is the opposite of the one the term implies. Sound amalgam fillings should not be removed for health reasons. Doing so releases more mercury than leaving them alone, and it destroys healthy tooth in the process.

The rest of this article is about why, what the UK rules actually say — they have changed considerably and are still changing — and where this set of ideas shades from reasonable into unsupported.

What amalgam is, and what it does

Dental amalgam is an alloy: mercury combined with silver, tin and copper, mercury making up around half of it. It has been used for well over a century because it is durable, tolerates a working field that is not perfectly dry, and is cheap.

It does release a very small quantity of mercury vapour, and more of it during chewing, grinding and brushing. That is not in dispute and never has been. What is at issue is whether that quantity matters, and the weight of evidence is that it does not: there is no established link between amalgam fillings and ill health at the exposures involved. The British Dental Association's position is that there is no evidence of harmful health effects from mercury in fillings.

The recognised exception is a genuine allergy to one of the constituents, which exists and is rare. It is diagnosed, not assumed.

One claim that needs correcting

It is widely repeated that mercury is a known cause of cancer. It is not.

The International Agency for Research on Cancer places metallic mercury and inorganic mercury compounds in Group 3 — not classifiable as to carcinogenicity in humans. Methylmercury compounds sit in Group 2B, possibly carcinogenic, and methylmercury is the form that accumulates in fish, not the form a filling releases.

Mercury is a genuinely toxic element. Its established effects at high exposure are on the nervous system and the kidneys. Describing it as a carcinogen is wrong, and it is wrong in a way that pushes people towards decisions they would not otherwise make.

The rules, which have been changing fast

Amalgam is being phased out across Europe, and the detail matters because it differs within the UK.

• Since 1 July 2018, across the UK, amalgam has not been used for children under fifteen, for baby teeth, or for women who are pregnant or breastfeeding — except where a dentist judges it strictly necessary.
• Since 1 January 2019, it may only be used in pre-dosed encapsulated form rather than mixed in the surgery, and practices must fit amalgam separators so that waste does not reach the water system.
• In the EU, the use and export of dental amalgam has been prohibited since 1 January 2025, and its manufacture and import from 1 July 2026.
• In Great Britain, it is not banned. It remains legal and in use, including on the NHS, under the 2018 restrictions above.
• In Northern Ireland, EU rules apply through the Windsor Framework, but a derogation permits continued import and use until the end of 2034, or earlier if a date is agreed under the Minamata Convention. The Control of Mercury (Enforcement) (Amendment) Regulations 2025 put the enforcement arrangements in place.

The reason behind all of this is the part most often got wrong. The Minamata Convention is an environmental treaty about mercury released into the environment. The phase-down of dental amalgam follows from that, not from any finding that fillings harm the people who have them. A regulatory timetable driven by what happens to mercury in water and soil is routinely presented as official confirmation that amalgam is dangerous to patients. It is not the same thing, and the restrictions on children and pregnancy are precautionary rather than evidence of harm.

Most new fillings are not amalgam in any case

Tooth-coloured composite is now the usual material for most new work, with glass ionomer and others used where they suit. So for a cavity being filled today the question has largely answered itself, and a patient who would rather not have amalgam can generally simply say so.

Amalgam persists where its properties still win: large cavities under heavy biting load, back teeth, and situations where a dry field is hard to maintain. What each material is good for is covered under fillings, crowns and implants.

Why removing sound fillings is the wrong move

Three things happen when an intact amalgam is drilled out.

The mercury exposure goes up, not down. Drilling turns a solid filling into vapour and particles in a single session — more than the filling would have given off over years in place. Anyone removing fillings to reduce their mercury exposure achieves the reverse.

Healthy tooth is lost. A replacement cavity is always bigger than the one before it. Enough cycles of replacement and a tooth that needed a filling needs a crown, or root canal treatment, or eventually comes out.

It costs money and achieves nothing measurable. This work is private, and a mouthful of restorations is not a small bill. Paying for dental care covers what is and is not available on the NHS.

The professional position in the UK is consistent. The 2018 restrictions did not require existing fillings to be replaced, and the Dental Defence Union advises dentists asked about it to consider whether replacement actually serves the patient's interests, to reassure them about long-term safety, to explain the risks of replacement, and to record the conversation. A dentist proposing wholesale removal as treatment for an unrelated illness has gone well past the evidence.

There are perfectly ordinary reasons to replace an amalgam: it has failed, there is decay underneath, the tooth or the filling has cracked, or the patient dislikes the appearance and accepts the loss of tooth tissue that changing it involves. That is routine dentistry and no one objects to it. The distinction is between replacing a filling for a dental reason and removing a sound one as a medical treatment.

And if someone wants amalgam out of their mouth because they would rather it were not there, that is their decision to make. It is simply worth making it knowing that it is a preference with a cost, not a cure.

Where this set of ideas goes beyond the evidence

Mercury-free dentistry and environmental responsibility are reasonable things. Several claims that travel alongside them are not, and they are the ones that lead to irreversible treatment.

• Root-filled teeth as a cause of disease elsewhere in the body, and the recommendation to extract them. The focal infection theory behind this was abandoned by mainstream dentistry decades ago for want of evidence. Extracting a sound root-filled tooth cannot be undone. See root canal treatment.
• Surgery on supposed jawbone "cavitations" said to harbour hidden infection. This is not a recognised diagnosis, and the procedure is real surgery.
• Advice to avoid fluoride. It is the single most effective measure against decay there is, and the reasoning is set out under fluoride and teeth.
• Commercial "biocompatibility" or material-sensitivity testing offered to select which materials a patient should have. Dental materials are regulated medical devices and are already subject to biocompatibility standards before they may be sold; the tests sold to choose between them do not have evidence behind them.
• The claim that an existing cavity can be reversed by diet. Early decay genuinely can be arrested and remineralised. A cavity — an actual hole — cannot, and treating one as though it can means it gets bigger.

What is genuinely environmental about a dental practice

This part is real, and the original framing deserves credit for raising it even if it reached the wrong conclusions.

Amalgam separators, now mandatory, exist because mercury entering wastewater from dental practices was a meaningful source of environmental contamination — and that, rather than any effect on patients, is what the whole phase-down is about. Beyond mercury, practices deal with clinical waste streams, a great deal of single-use plastic, water and energy use, and the travel that patients and staff make to get there.

All of which is worth a practice attending to. None of it tells a patient anything about whether the filling in their tooth is safe. Those are two separate subjects that the label "environmental dentistry" runs together.

Regulation, and choosing a practice

Anyone practising dentistry in the UK must be registered with the General Dental Council, whatever the practice calls itself, and the register can be searched directly. "Holistic dentist", "biological dentist" and "environmental dentist" are not recognised dental specialties and appear nowhere on the GDC's specialist lists, so the description carries no information about training or qualification.

A practice that prefers not to place amalgam is making an ordinary choice, and an increasingly common one. A practice proposing to remove existing restorations in order to treat an illness is making a quite different offer. Reasons to stop and think, and to get a second opinion:

• A diagnosis of a general medical condition made from the state of the mouth.
• A recommendation to remove sound fillings, or to extract root-filled teeth, as treatment for something other than a dental problem.
• Advice against fluoride, or against treatment recommended elsewhere.
• A test sold to determine which materials the body will accept.
• Discouragement from seeking another opinion.

See also dental health for the rest of this section, and alternative therapies for the same question in other settings.