You probably already know that oral health is one of my passions. I’ve had several dentists on the podcast to discuss common dental health questions, and one reoccurring topic is how to prevent tooth decay and cavities. What’s the big deal about cavities and amalgam fillings? Well, besides the pain, expense, and annoyance of getting a filling, there’s also what’s in the filling to consider (hint: it isn’t good). 

What Are Amalgam Fillings?

Dental amalgam is a tooth-filling material made with about 50% mercury (the other 50% is a tin, copper, and silver alloy). Many of us have these silver fillings in our teeth, as this material has been used for years in the dental world.

How Bad Are Amalgam Fillings Anyway?

Amalgam fillings are very common but are, unfortunately, also very toxic. Here’s what you need to know about them.

Mercury

Amalgam fillings contain mercury, an incredibly toxic substance to the human body. Mercury is a known neurotoxin and also a reproductive toxin. Studies link mercury levels in the body to inflammatory disease.

Mercury is released into the body when:

• the dentist places or removes the amalgam in the tooth
• you chew food or gum
• you brush your teeth
• you grind your teeth

In 2009, the FDA reviewed scientific evidence surrounding amalgam fillings. It reclassified mercury from a class I risk (least risk) to a class II risk (more risk). It also classified amalgam fillings as a class II risk. The FDA wrote in their guidance document:

“(D)ental amalgam also releases low levels of mercury vapor, a chemical that at high exposure levels is well-documented to cause neurological and renal adverse health effects. Mercury vapor concentrations are highest immediately after placement and removal of dental amalgam but decline thereafter.”

Strangely enough, the FDA still considered amalgam fillings to be safe for people over six years old. Here’s a history of new regulations over the past decade:

• In 2011, the World Health Organization called for a phasing out of amalgam fillings.
• In 2011, the public challenged the FDA to follow suit and protect the public from amalgam fillings.
• In 2013, an international treaty passed the United Nations Minamata Convention on Mercury. This treaty required countries to phrase out many mercury-containing products, including thermometers. It also calls for an end to all mercury mining within 15 years. In May 2017, they reached the 50 ratification milestone (at least 50 countries agreed to sign the treaty), and the phasing out of mercury could begin. Though the U.S. government has agreed to this treaty, we haven’t seen much done yet.

Then in 2016, researchers found (in a study performed in 2003-2004) that people with more than eight dental fillings had 2.4 times the amount of mercury in their blood as those who had no fillings. A later group (in a study performed in 2011-2012) found a similar association, but the amount was slightly less, probably because more of these fillings were composite (non-mercury fillings). The amount of mercury in this study was below what the EPA considers safe (.002 mg/L). 

One of the researchers mentioned this was only an average, which means some people had levels higher than the EPA’s limit. If you add in other environmental sources of mercury (like fish consumption, vaccines, etc.), some people can easily have a dangerous level of mercury in their bodies.

This study also found increases in the more dangerous form of mercury—methylmercury—which is known to be dangerous at much lower levels.

The American Dental Association (ADA) responded to the research by releasing a statement reaffirming its position that “dental amalgam is a safe, durable, and effective cavity-filling option.” They went on to say that no conclusions should be drawn about safety from this study.

Bottom Line: Mercury is a known toxin, and amalgam fillings release some mercury into the body. When we have plenty of alternatives to amalgams, there’s just no reason to continue using them.

Tooth Damage

The material in the filling expands and contracts due to temperature changes, which can cause cracking and breaking in the tooth. Placing the amalgam filling also requires dentists to remove a lot of the healthy parts of the teeth. This removal weakens the tooth and makes it more susceptible to breaking and cracking (and more dental procedures in the future). Composite fillings require less of the healthy parts of the tooth to be removed.

Environmental Issues 

Mercury pollution is also a problem. Dental mercury enters the environment by:

• Air – cremation smoke, sewage sludge, waste incineration, and dentist clinic emissions 
• Water – human waste disposal and dental clinics 
• Land – landfills, burials, and fertilizers

After mercury enters the environment, microorganisms turn elemental mercury into methylmercury, which builds up in fish, shellfish, and people who eat mercury-containing fish. Methylmercury can cause damage to children’s and fetuses’ developing brains and nervous systems.

The mercury in fillings not only affects the person with the fillings but everyone else too (especially people who eat fish).

Signs of Mercury Toxicity

The amount of mercury in the body isn’t a direct representation of whether mercury is being harmful. Studies show that the body reacts to mercury by releasing pro-inflammatory immune cells, which means mercury in the body can increase the risk for infectious or autoimmune diseases.

Inflammation can also make the body more susceptible to mercury toxicity. According to Amy Nett in a guest post on Chris Kresser:

“In one study, inflammation due to different causes, including exposure to bacterial endotoxin, which occurs with food poisoning or other GI infection, significantly increased toxicity. Another study similarly found that small amounts of bacterial endotoxin exposure substantially increased susceptibility to damage from various toxins, including metals. And another study in mice demonstrated that mercury in the presence of bacterial endotoxin caused measurably more kidney damage than mercury alone. This means that the same amount of mercury or other toxins will cause more damage in the presence of inflammation.”

Therefore, the way mercury toxicity plays out in a body is very individual. However, here are some general symptoms that can indicate mercury toxicity:

• Anxiety or depression 
• Brain fog, decreased concentration, memory problems
• Fatigue
• Frequent headaches
• Lack of motor skills/feeling uncoordinated
• Autoimmune disease
• Allergies 
• Multiple chemical sensitivity
• Nerve damage (phantom pain or sensations)
• Hearing loss
• Slow or slurred speech
• Muscle tremors
• Hair loss 
• Hormonal dysregulation, including abnormal menstrual cycles and infertility
• Cardiovascular disease 
• Kidney dysfunction 

In children:

• Sleep disturbance
• Delayed or impaired motor skills
• Difficulties learning to speak
• Issues with hand-eye coordination

Many of these symptoms could indicate other illnesses or causes, so it’s essential to work with a knowledgeable naturopath or functional medicine doctor to determine what’s causing your or your child’s symptoms.

A hair mineral analysis test can reveal what metals are in excess in your body.

More testing may be needed, as a hair mineral test may not be enough, which is why a knowledgeable doctor is so important!

Alternatives to Amalgam Fillings

I mentioned earlier that there are no good reasons to continue using amalgam fillings since many good alternatives exist. Here are some of the best and safest alternatives to mercury fillings.

Composite Resin

Composite resin fillings are made out of a type of plastic (an acrylic resin) reinforced with powdered glass filler that is white and matches the tooth. Composite fillings contain BPA, but studies have found no correlation between the number of fillings and levels of BPA in the blood (suggesting that composite fillings don’t release BPA the way amalgam fillings release mercury). Ideally, it would be best to avoid either, but composite is a better choice between the two (amalgam or composite). Composite fillings are also long-lasting.

Remineralizing Cavities Naturally

As Dr. Weston A. Price (a dentist) found and detailed in Nutrition and Physical Degeneration, some cultures throughout the world had perfect teeth despite no access to dentists or modern toothpaste. On the other hand, similar cultures with different diets had very high rates of tooth decay.

He (and others) eventually uncovered that diet is the main factor in tooth structure and health. Yes, that means diet even affects whether a child needs braces!

There are three main parts to a diet that helps strengthen teeth (versus one that causes cavities):

1. Enough dietary minerals
2. Enough dietary fat-soluble vitamins (A, D, E, and K)
3. Bioavailability of these nutrients and if a person can absorb them

When I changed my diet to improve my oral health, I actually remineralized some cavities!

What to Do If You Already Have Amalgam Fillings

If you already have some amalgam fillings and want to get them removed, it’s not as simple as going to your regular dentist. The removal of amalgam fillings can release a lot of mercury into the body, and many dentists don’t know how to remove amalgam fillings safely. A holistic dentist (also called a biological dentist) can remove amalgam fillings safely. You can find one near you:

Have you had an amalgam filling removed? How did it go?

Sources:

1. Gump, B. B., et al. (2011, October 24). Fish consumption, low-level mercury, lipids, and inflammatory markers in children. Environmental Research. 
2. Center for Devices and Radiological Health. (n.d.). Appendix I : Summary of changes to the classification of Dental Amalgam. U.S. Food and Drug Administration.
3. WHO. (n.d.). Future use of materials for dental restoration.
4. International Academy of Oral Medicine and Toxicology. (2018, June 30). Public demands FDA take immediate action on Mercury fillings. 
5. Environmental Protection Agency. (n.d.). Minamata Convention on Mercury. EPA. 
6. MacMillan, A. (2016, October 4). How dental fillings can impact mercury levels on your blood. Time. 
7. Novo, J. P., et al. (2021). Cellular and Molecular Mechanisms Mediating Methylmercury Neurotoxicity and Neuroinflammation. International journal of molecular sciences, 22(6), 3101. 
8. What is dental amalgam? (n.d.). ToxicTeeth.org.
9. Gardner, R. M., et al. (2009, December). Mercury induces an unopposed inflammatory response in human peripheral blood mononuclear cells in vitro. Environmental health perspectives. 
10. Nett, A. (2015, August 11). Mercury toxicity – is it the cause for your symptoms. Chris Kresser.