Dental Amalgam Fillings and Hypothyroidism

In this article

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For over 150 years, “silver fillings” have been the go-to for filling cavities. These fillings, properly known as dental amalgam, contain liquid mercury.

Mercury is a known trigger of autoimmune diseases, including Hashimoto’s thyroiditis. Since Hashimoto’s thyroiditis is the primary cause of hypothyroidism, you may wonder if your “silver fillings” affect your thyroid function. 

This article will explore the relationship between dental amalgam and thyroid function. But first, let’s review the basics of dental amalgam fillings and mercury. 

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Dental amalgam is a filling material used to fill cavities caused by tooth decay. Your dentist mixes liquid (elemental) mercury with powdered silver, copper, and tin mixture before placing it into your tooth. Once in your tooth, the mercury amalgam mixture rapidly hardens, forming a strong, solid, silver filling.

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Mercury is a chemical naturally occurring in rocks, including the earth’s crust. It exists in three forms:

• Elemental, also known as metallic mercury, is a liquid. Barometers, fluorescent lights, and some light switches can contain this form of mercury.
• Inorganic mercury compounds enter the environment through coal burning or manufacturing processes. Some jobs, such as mining and electrical equipment manufacturing, expose workers to higher levels of these compounds. Lastly, some skin-lightening facial creams may also contain these mercury compounds.
• Methylmercury and organic compound exposure come from eating fish and shellfish high in methylmercury.

Elemental mercury

Dental amalgams use elemental mercury, a liquid metal that appears silvery-white at room temperature. There is little risk of mercury exposure when it’s contained, like in a thermometer or barometer. But when exposed to room temperature air, mercury evaporates into a toxic, odorless vapor you could inhale. Long or short-term exposure to elemental mercury can cause symptoms of:

• Cognitive problems and memory decline
• Emotional changes
• Headaches
• Nerve damage
• Tremors
• Trouble sleeping

About half of dental amalgam by weight is elemental mercury. Because of this, studies have tried to link dental amalgam to adverse health effects, including thyroid dysfunction. The concern is that the amalgam could break down as you brush, chew, or grind your teeth. These actions release small amounts of mercury vapors that we inhale. But, the estimated quantities inhaled from dental amalgams are considered within the safe exposure limits established by the Environmental Protection Agency (EPA).

Specific populations may be at greater risk of adverse effects associated with mercury exposure, including the following:

• Women who are or plan to become pregnant
• Nursing women and their infants
• Children under the age of six 
• Individuals with a sensitivity to mercury or other components of dental amalgam
• Those with kidney impairment
• Those with neurological disorders

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Studies show that mercury can accumulate in thyroid cells, resulting in thyroid disorders. Researchers believe that mercury causes thyroid disorders by: 

• Changing your genetic makeup. By changing your genes, mercury promotes the formation of certain types of cancer, including thyroid cancer.
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•  Causing Hashimoto’s thyroiditis, an autoimmune disorder. Mercury promotes autoimmune reactions, mistakenly triggering your immune system to destroy healthy cells. When there are high levels of mercury in your thyroid cells, your immune system may destroy healthy thyroid cells, resulting in Hashimoto’s thyroiditis.
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• Increasing oxygen free radicals. Oxidative stress is an imbalance between harmful free radicals and beneficial antioxidants. Having more free radicals promotes inflammation in our bodies. The resulting chronic inflammation may contribute to the risk of developing an underactive thyroid, including Hashimoto’s thyroiditis.

In addition, a 2022 study suggests that dietary mercury may bind to selenium. While this helps prevent the harmful side effects of mercury, it could lead to a selenium deficiency. Without enough selenium, your cells won’t be able to convert the thyroid hormone thyroxine (T4) into its active form, triiodothyronine (T3). As a result, you may experience symptoms of hypothyroidism, including the following:

• Cold intolerance
• Constipation
• Dry skin
• Fatigue
• Joint pain
• Mental health changes
• Muscle weakness
• Trouble sleeping
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There appears to be a link between mercury exposure in general and adverse health effects. But, whether the mercury from dental amalgams can cause thyroid problems is highly debated. Here’s a rundown of some of the study findings. 

A small 2004 study examined the benefits of removing dental amalgam in 35 participants with an autoimmune disorder. The results showed that:

• 71% had improvements in their health
• 17% had no change in health
• 11% had worsening health

Eight of the participants in the 2004 study had autoimmune thyroiditis. The majority (five) reported feeling their health improved after amalgam removal. Based on mercury samples before and after, participants with improved health had at least a 50% decrease in mercury-induced lymphocytic activity levels. Lymphocytes are part of your immune system that help make antibodies.

A 2007 study based on 30 autopsy results showed higher mercury concentrations in the brain, pituitary, and thyroid gland. Furthermore, those with higher levels of mercury had more dental amalgam fillings. This study notes that mercury absorption may occur in the GI tract as dental amalgams corrode and break off.

In 2009, the Food and Drug Administration (FDA) released the results of their review of available studies on dental amalgams and adverse side effects. They concluded, “there is insufficient evidence to support an association between exposure to mercury from dental amalgams and adverse health effects in humans, including sensitive subpopulations.”

A 2014 study looked at whether dental amalgam fillings trigger Hashimoto’s. Results showed that those with Hashimoto’s did not have significantly more amalgam fillings than those without Hashimoto’s. Thus, the study could not demonstrate or prove a link between Hashimoto’s and amalgam fillings.

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The 2004 study showed that removing dental amalgam may benefit those with an autoimmune disorder. The first step is always to start by talking with trusted dental and healthcare providers about the risks and benefits of removing them. 

Keep in mind, however, that if you choose to have amalgam fillings removed, it requires specialized training to do so safely. You’ll likely have the best results if you work with what’s known as a “biological dentist,” an integrative dentist who combines clinical practices and technologies of Western dental medicine with other modalities and approaches. Biological dentists are fluoride-free, mercury-free, and mercury-safe and are trained in protocols for the safe removal of mercury fillings. To find a biological dentist, see the website of the International Academy of Biological Dentistry & Medicine (IABDM)

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Maintaining your oral health keeps your smile healthy and, hopefully, cavity-free. The American Dental Association suggests:

• Visiting your dentist regularly
• Brushing your teeth two times a day
• Flossing daily
• Eating a healthy diet
• Avoiding tobacco products and oral piercings

Just like regular dental appointments help you keep a healthy smile, regular thyroid checkups help you maintain a healthy thyroid. Our thyroid specialists at Paloma Health are here to help. Make a virtual appointment with one of them today.

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