Mercury in Dentistry

All silver-colored fillings, also called “dental amalgams,” contain 45-55% metallic mercury.1  Dental amalgams are used for 45% of all direct dental restorations worldwide,2 and it has been estimated that these mercury-containing fillings are used on more than 50% of Americans.3 4  While hazards to the environment and human health from dental mercury have been established and some countries have banned or restricted its use, the U.S. Food and Drug Administration (FDA) “considers dental amalgam fillings safe for adults and children ages 6 and above.”5

Dental amalgam mercury pollutes the environment through wastewater from dental offices, human waste, cremation and burial, and emissions of mercury vapor.  Once in the environment, mercury pollution damages animals, plants, and the entire ecosystem, with dangers existing as a result for centuries.6  More information about dental mercury’s harm to the environment.

Human health risks have been clearly associated with the use of dental mercury.  Scientific research has related the mercury in dental amalgam to Alzheimer’s disease,  amyotrophic lateral sclerosis (Lou Gehrig’s disease), antibiotic resistance, autism spectrum disorders, autoimmune disorders/immunodeficiency, cardiovascular problems, chronic fatigue syndrome, hearing loss, kidney disease, multiple sclerosis, Parkinson’s disease, reproductive dysfunction, and other health problems.7  Additionally, authorities have issued distinct warnings about mercury’s use in children and pregnant women.  Furthermore, scientific studies have demonstrated potential hazards of mercury in the workplace to dental workers and dental students. 8  For more information about the health risks of dental mercury.

Potential responses to elemental mercury, the form used in dental amalgam fillings, include hundreds of specific symptoms, which can vary from person to person and change over time.  Mercury vapor is absorbed by the lungs and passed to the rest of the body, particularly the brain, kidney, liver, lung, and gastrointestinal tract. The half life of metallic mercury varies depending on the organ where the mercury was deposited and other factors. More information on the symptoms and effects of mercury exposures.

Some consumers have mercury-containing amalgam fillings removed due to device failure, personal preference, or other reasons.  However, it is important to note that removal of dental mercury requires a number of precautions because an unsafe amalgam removal process releases mercury vapor and particles that can be harmful to the patient, the dentist, the dental staff, and the environment.   The International Academy of Oral Medicine and Toxicology (IAOMT) has developed safety recommendations for the removal of existing dental mercury amalgam fillings known as the Safe Mercury Amalgam Removal Technique (SMART). More information about SMART.

Alternatives to amalgam fillings include composite resin, glass ionomer, porcelain, and gold, among other options.  Most consumers choose direct composite fillings because the white coloring matches the tooth better and the cost is considered moderate. More information on alternatives to mercury fillings.

More detailed information about dental amalgam mercury with references to scientific literature:

A Comprehensive Review of the Toxic Effects of Mercury in Dental Amalgam Fillings on the Environment And Human Health (pdf)

IAOMT Position Paper Against Dental Mercury Amalgam

1 World Health Organization. Mercury in Health Care [policy paper].  August 2005: 1.  Available from WHO Web site: http://www.who.int/water_sanitation_health/medicalwaste/mercurypolpaper.pdf.  Accessed December 15, 2015.

2 Heintze SD, Rousson V.  Clinical effectiveness of direct Class II restorations—a meta-analysis.  J Adhes Dent. 2012; 14(5):407-431.

3 Makhija SK, Gordan VV, Gilbert GH, Litaker MS, Rindal DB, Pihlstrom DJ, Gvist V.  Dental practice-based research network restorative material: Findings from the characteristics associated with type of practitioner, patient and carious lesion. J Am Dent Assoc. 2011; 142: 622-632.

4 Simececk JW, Diefenderfer KE, Cohen ME.  An evaluation of replacement rates for posterior resin-based composite and amalgam restorations in U.S. Navy and Marine recruits. J Am Dent Assoc. 2009; 140 (2): 207.

5 United States Food and Drug Administration. About dental fillings: potential risks.  Last updated 2 February 2015.  Available from FDA Web site:  fda.gov/MedicalDevices/ProductsandMedicalProcedures/DentalProducts/DentalAmalgam/ucm171094.htm.  Accessed December 15, 2015.

6 Pirrone N, Mason R.  Mercury Fate and Transport in the Global Atmosphere: Emissions, Measurements, and Models.  New York, New York: Springer. 2009: 166.

7 For a detailed list of health risks related to dental mercury, see Kall J, Just A, Aschner M.  What’s the risk? Dental amalgam, mercury exposure, and human health risks throughout the lifespan.  Epigenetics, the Environment, and Children’s Health across Lifespans. David J. Hollar, ed. Springer. 2016. pp. 159-206 (Chapter 7).

And Kall J, Robertson K, Sukel P, Just A. International Academy of Oral Medicine and Toxicology (IAOMT) Position Statement against Dental Mercury Amalgam Fillings for Medical and Dental Practitioners, Dental Students, and Patients. ChampionsGate, FL: IAOMT. 2016.  Available from the IAOMT Web site: iaomt.org/iaomt-position-paper-dental-mercury-amalgam/.  Accessed December 18, 2015.

8 For a detailed list of health risks to dental workers and students related to dental mercury, see Kall J, Just A, Aschner M.  What’s the risk? Dental amalgam, mercury exposure, and human health risks throughout the lifespan.  Epigenetics, the Environment, and Children’s Health across Lifespans. David J. Hollar, ed. Springer. 2016. pp. 159-206 (Chapter 7).

And Kall J, Robertson K, Sukel P, Just A. International Academy of Oral Medicine and Toxicology (IAOMT) Position Statement against Dental Mercury Amalgam Fillings for Medical and Dental Practitioners, Dental Students, and Patients. ChampionsGate, FL: IAOMT. 2016.  Available from the IAOMT Web site: iaomt.org/iaomt-position-paper-dental-mercury-amalgam/.  Accessed December 18, 2015.

How Mercury Causes Brain Neuron Damage

Medical laboratories have established that dental amalgam tooth fillings are a major contributor to mercury body burden. This short presentation on University of Calgary’s Faculty of Medicine’s website reveals how mercury ions actually alter cell membrane structure and how mercury in fillings can destroy brain neurons as seen with people who have Alzheimer’s Disease.

Why We All Don’t Get Sick in the Same Way

The Science Behind Dental Mercury and Other Environmental Toxicants

By Amanda Just and John Kall, DMD of the International Academy of Oral Medicine and Toxicology (IAOMT)

If everyone had the same reaction to environmental toxicants, these hazardous substances would probably be banned immediately. It would be obvious to everyone, as well as their doctors, that exposure to a specific toxic material results in a definitive outcome– the exact same illness shared by all of those who come into contact with the dangerous substance. However, research has demonstrated that individuals respond to environmental toxicants in a way that is unique to their own bodies.

This “personalized response” has been studied in depth in the case of dental mercury. In fact, examining the science behind dental mercury sheds light on the complex variability of environmental illnesses. It also offers hope that this newfound understanding can help heal the ailing state of 21st century public health.

What is dental mercury?

Often referred to as “silver fillings,” all dental amalgams consist of 45-55% metallic mercury. Mercury is a known neurotoxin.  Amalgams are still used for about 45% of all direct dental restorations worldwide, including in the US.

What are some of the health risks that have been linked to dental mercury?

Properly diagnosing “adverse health effects” related to dental mercury amalgam fillings is impeded by the list of potential responses to the elemental form of the substance, which include over 250 symptoms. Not all individuals will experience the same symptom or combination of symptoms. Moreover, scientists have associated the mercury in amalgam fillings with Alzheimer’s disease, amyotrophic lateral sclerosis (Lou Gehrig’s disease), antibiotic resistance, anxiety, autism spectrum disorders, chronic fatigue syndrome, depression, infertility, kidney disease, multiple sclerosis, Parkinson’s disease, and other health problems. 

Response factor #1: The form of the substance

Mercury exists in different forms and compounds, and these different forms and compounds can produce different results in humans that are exposed to them. The type of mercury used in amalgam fillings is elemental (metallic) mercury. In contrast, the mercury in fish is methylmercury, and the mercury in the vaccine preservative thimerosal is ethylmercury.

Response factor #2: Different organs within the body

Another reason for the wide-range of symptoms is that mercury can accumulate in virtually any organ. In the case of dental mercury fillings, an estimated 80% of this mercury vapor is absorbed by the lungs and passed to the rest of the body, particularly the brain, kidney, liver, lung, and gastrointestinal tract. The half life of metallic mercury varies depending on the organ where the mercury was deposited.

Response factor #3: Delayed effects 

Symptoms of toxic exposures can take many years to manifest themselves. For example, the Occupational Safety and Health Administration (OSHA) recognizes that chronic diseases related to toxic exposures can have latency periods of 20-30 years or longer.

Response factor #4: Allergies 

Allergies and hypersensitivities are yet another essential aspect of reactions to toxic substances. Since most patients are not tested for mercury allergies prior to dental amalgam exposure, as many as 21 million people could be unknowingly allergic to the mercury in their mouths.  However, this figure could be higher since metal allergies are reportedly on the rise. 

Response factor #5: Genetic predisposition 

A growing volume of recently published scientific research is examining how mercury exposure can pose highly significant risks to individuals with specific genetic traits including CPOX4, APOE, BDNF, MT polymorphisms, COMT variants, MTHFR mutations, and PON1 variants. A 2016 news story featuring several prevalent dental mercury researchers established that 25-50% of people have these genetic variants and endure “a lifetime risk” of neurological damage.

Response factor #6: Other considerations

In addition to the weight and age of the individual, as well as other existing health conditions, the number of amalgam fillings, gender, dental plaque, diet, consumption of milk or alcohol, and other circumstances can play a role in each person’s unique response to mercury. Another important consideration is the synergy between different toxic exposures experienced by the same individual.

Conclusion

Clearly, the precise way that a person’s body responds to an environmental toxicant is based on a spectrum of circumstances and conditions. The factors described in this article are only a fraction of numerous pieces in the puzzle of adverse health effects related to toxic exposures. The science behind dental mercury demonstrates that in order to fully understand environmental illness, we need to recognize that just as each toxic exposure is unique, so is each person impacted by such a toxic exposure. As we accept this reality, we also offer ourselves the opportunity to create a future where dentistry and medicine acknowledge that each patient responds to materials and treatments differently. We also offer ourselves the opportunity to use safer products that reduce the overall toxic burden in our bodies and forge the path to renewed health.

To read a more detailed version of this article, including citations and scientific sources of information, click here to visit the webpage from the IAOMT.

To mitigate mercury exposure during amalgam filling removal, SMART-certified dentists use protective gear for themselves and their patients. For more “SMART” removal recommendations, go to https://iaomt.org/safe-removal-amalgam-fillings/ and to www.theSMARTchoice.com

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