Dental Amalgam & Mercury: What the Evidence Says

Written by Empire Medical Training Editorial Team

Medically reviewed by Peter Bongiorno, ND, LAc Naturopathic Doctor & Licensed Acupuncturist; Integrative & Functional Medicine

Updated June 2026 ·11 min read

Few topics in heavy-metal medicine generate as much heat as dental amalgam. To one audience, “mercury fillings” are an obvious hazard that should be ripped out; to another, the concern is overblown internet folklore. The honest answer lives between those poles, and it rewards a clinician who can hold two true statements at once: amalgam does release mercury, and the major medical and dental bodies still consider it safe for most people. This guide lays out both sides candidly, without the fear-mongering that so often surrounds the subject.

It belongs to our broader cluster on heavy metal toxicity and is written for clinicians. It is clinical education, not medical advice, and nothing here is a recommendation to remove or retain any specific filling.

What is dental amalgam?

Dental amalgam is the classic “silver filling” that has been used in dentistry for more than 150 years. It is an alloy made by combining liquid mercury with a powder of silver, tin, and copper. By weight, the finished filling is approximately 50% elemental mercury, which is what binds the other metals into a hard, durable, inexpensive material that holds up well under chewing forces. That durability and low cost are why amalgam was the workhorse of restorative dentistry for generations.

The mercury in amalgam is elemental mercury — the liquid, silvery form many people remember chasing around when a thermometer broke as a child. As covered in our overview of mercury toxicity, elemental mercury is the least biologically aggressive of mercury's three forms (elemental, inorganic, and organic methylmercury), but it is not inert. It can vaporize into an odorless, colorless gas, and that vapor is the crux of the amalgam question. A set filling is not liquid mercury sitting in the tooth, but it is a long-term, slow source of mercury vapor — which is precisely why the debate exists.

How much mercury exposure does amalgam actually add?

Amalgam fillings release very small amounts of mercury vapor over time, and that release increases transiently with chewing, grinding (bruxism), tooth-brushing, and hot liquids. Inhaled vapor is absorbed efficiently and is the relevant exposure route here. For most people with a typical number of fillings, this represents a measurable but generally low-level chronic source of mercury — real, but modest relative to other contributors.

Context matters enormously. For the general population, the largest dietary mercury source is fish and shellfish — particularly methylmercury that accumulates up the food chain in larger predatory fish. Dr. Bongiorno's clinical cases repeatedly trace elevated mercury back to diet: the patient eating albacore tuna every day, the sushi enthusiast. Amalgam is named in the same breath as those food and occupational sources, not above them. The clinically sensible framing is that amalgam is one chronic input on a longer list, and the reassuring trend is that mercury use in dentistry has been declining for years as composite resin alternatives have improved.

This is also why amalgam is best understood through the lens of cumulative body burden rather than as a single villain. Whether a given person's total mercury load matters clinically depends on the sum of their exposures, their individual biology, and their other risk factors — not on the presence of fillings alone.

The evidence — and the honest debate

Here is where candor matters most. There are two recognizable positions, and a responsible clinician understands both.

The mainstream position. The U.S. FDA, the American Dental Association, and the World Health Organization consider dental amalgam a safe and effective restorative material for the general adult population. Their conclusion is that the low levels of mercury vapor released by intact fillings do not, on current evidence, cause harm in most people. On this view, there is no validated disease entity called “amalgam illness,” and the published evidence does not support removing sound fillings to treat or prevent systemic illness. This is the consensus position, and it should be represented honestly rather than dismissed.

The functional / biological-dentistry view. A segment of integrative and biological-dentistry practitioners argues that for some individuals — especially those with high total body burden, genetic differences in detoxification, or mercury sensitivity — even low-level chronic exposure may contribute to symptoms. This aligns with the broader environmental-medicine framing Dr. Bongiorno teaches: that multiple small doses of various metals, each below the threshold of formal toxicology, can together contribute to disease in a susceptible person. It is a legitimate clinical philosophy, but it is important to be clear that “amalgam illness” as a defined diagnosis, and routine removal-for-health, are not established by the weight of mainstream evidence.

Where the two views nearly meet: the FDA's 2020 advisory. In September 2020, the FDA updated its guidance and identified groups who may be at higher risk from mercury vapor and for whom alternatives could reasonably be preferred when placing new fillings: pregnant women and those planning pregnancy, nursing mothers, children (especially under six), people with pre-existing neurological disease, those with impaired kidney function, and people with known mercury allergy or sensitivity. Crucially, the FDA did not recommend that people in these groups remove existing intact fillings, and it did not conclude that amalgam had harmed them — this is a precautionary stance for new placements, not a reversal of the safety position. Presenting it as proof of harm would overstate it; ignoring it would understate it.

Safe-removal considerations

If a filling is genuinely failing — decayed underneath, cracked, or leaking — it needs to come out for ordinary dental reasons, and the question becomes how to remove it well. The counterintuitive but important point is that drilling out an amalgam is the moment of highest mercury vapor exposure in the filling's entire life. Removing a sound filling unnecessarily therefore exposes the patient (and the dental team) to more mercury, not less. That is the central reason mainstream bodies advise against routine removal of intact fillings.

When removal is appropriate, protective technique exists to limit exposure during the procedure. A protocol of the SMART type (Safe Mercury Amalgam Removal Technique), promoted by biological-dentistry groups, conceptually layers measures such as copious water cooling and high-volume suction, rubber-dam isolation, supplemental air or oxygen for the patient, and operatory air management. The honest framing is critical: these measures are about reducing exposure during drilling — sensible occupational and patient-safety practice — and are not a claim that removing amalgam cures disease. Any provider who frames removal as a treatment for systemic illness has stepped beyond what the evidence supports.

Who might reasonably consider it

Stripped of hype, a short and defensible list emerges. Replacing or avoiding new amalgam is reasonable when:

• The filling has failed — decay, fracture, or marginal leakage. This is a standard dental indication and the most common legitimate reason a filling is removed.
• The patient falls into an FDA higher-risk group and a new restoration is being placed — pregnancy or planned pregnancy, nursing, young children, pre-existing neurological disease, impaired kidney function, or mercury allergy. Here, choosing a composite alternative is a reasonable precaution.
• Documented mercury sensitivity or allergy exists — a genuine, if uncommon, indication.
• The patient strongly prefers it after informed discussion — with an honest explanation of cost, the exposure spike during removal, and the lack of evidence that removal treats unrelated symptoms.

Notably absent from this list is “remove all amalgams to detox” in an otherwise healthy person with intact fillings. That is the recommendation the evidence does not support, and the one a candid clinician declines to make.

The responsible clinical stance

For clinicians working in heavy metals and chronic illness, amalgam is a test of intellectual honesty. The defensible posture is to confirm before you treat: if a patient has symptoms suggestive of mercury and amalgam is one of several plausible sources, the work-up looks the same as for any mercury concern — a careful exposure history, appropriate testing, and an honest weighing of the whole picture, as detailed in our guides on mercury toxicity and sources of exposure. Diet and occupation are usually larger levers than fillings.

What this stance is not: it is not selling block removal as a cure, not diagnosing “amalgam illness,” and not frightening patients about intact fillings. The credibility of an integrative practice is built precisely on refusing to overclaim — on being the clinician who can explain why amalgam releases mercury and why that usually does not warrant removal. That candor is what distinguishes responsible functional medicine from the marketing that gives it a bad name.

Training providers to talk about amalgam honestly

Patients arrive with strong opinions about “mercury fillings,” often shaped by alarmist content. The clinician's job is to be the calm, accurate voice in the room — able to validate the real chemistry, correct the overreach, cite the FDA's actual position, and route the patient toward decisions that match the evidence. That requires having genuinely studied the topic, not just absorbed one side of it.

Empire's curriculum situates amalgam within the full science of mercury and total body burden, connecting it to the heavy metal toxicity pillar and to dedicated provider heavy metals training for clinicians who want to address this area credibly.