DENTAL MERCURY, THE ENVIRONMENT,
AND SWEDEN’S SUCCESS STORY

By David Kennedy, DDS, MIAOMT, and Amanda Just

Mercury’s Damage to the Environment

Although human health risks related to mercury are of major concern, another main reason mercury regulations are being drafted and enforced is because mercury harms the environment. Mercury released into the air, soil, or water has devastating impacts on the ecosystem, including “land-degradation and river siltation and the associated deforestation, loss of organic soil, modification of hydrologic regimes and loss of aquatic habitat.”1 The pollution can also create “mercury hotspots that last for centuries.”2

The toxicity of fish from methylmercury, which is a form of the element transformed by certain bacteria, has resulted in advisories for pregnant women and children not to eat certain types of seafood.3,4,5

Dental Mercury and the Environment

It is well-known that the use of amalgam in dentistry causes mercury to be released to the environment. Consider for example that the United States Environmental Protection Agency (EPA) estimates dentistry accounts for 14% of the U.S. domestic usage of mercury annually.6 Also consider that approximately 40 tons of mercury are used each year to manufacture amalgam fillings.7

Research has shown that the primary source of mercury in municipal wastewater effluents generally originates from dental practices.8 In fact, according to the EPA, dental offices were found to have been the source of 50% of all mercury pollution entering publically-owned treatment works in 2003.9

Amalgam separators can successfully reduce the amount of mercury discharge in wastewater from dental offices10,11 and are essential in stopping mercury from entering the environment. However, it would be helpful to enforce maintenance requirements for amalgam separators, as the Royal College of Dental Surgeons has done in Ontario, Canada.12 It should also be remembered that amalgam separators only contribute to solving the problem of dental mercury in wastewater and not the additional burdens placed by amalgam fillings on the environment and human health.

Other burdens to the environment caused by amalgam include mercury released in human waste from patients with these fillings,13 improper disposal of amalgam at dental offices,14,15 mercury vapors given off of the fillings,16,17 and air discharges from central vacuum systems.18,19

Additionally, dental offices contribute to atmospheric releases of mercury from vapors given off during the cremation of individuals with amalgam fillings.20,21,22,23 Regarding this as a major source of air pollution is becoming more and more publicly accepted, a fact which is validated by lawsuits.24,25,26,27

For these reasons and more, a variety of environmental agencies have taken measures against dental mercury. The United Nations Environment Programme recently passed a worldwide mercury treaty, which includes working to phase-down dental mercury,28 and in the United States, many state environmental agencies, such as the Connecticut Department of Environmental Protection, have worked to educate dentists29 and consumers30 about pollution caused by amalgam and health risks from mercury.

The Example of Sweden

Sweden was one of the first countries to identify mercury as a persistent environmental biological toxin, and this initiated their evolution into one of the first mercury-free countries in the world. Some have mistakenly described Sweden’s approach to the mercury issue as recycling. Rather, according to the Nordic Council of Ministers, the Swedish government does not suggest recycling but does endorse appropriately handling mercury waste: “The Swedish government has proclaimed, that mercury should not be recycled and that mercury waste should be treated in a way, that makes it possible to store mercury appropriately in the long time perspective. The Swedish EPA recommends a deep mountain depot as the environmentally most safe disposal solution.”31

The Swedish EPA also trained dogs to sniff out residual mercury from abandoned buildings such as manufacturing plants and schools.32 With the dogs’ help, they identified hot spots and recovered and stored even more of this highly toxic metal. This dramatically cleaned up their country from the legacy of uncontrolled manufacturing.

Overall, there were very few difficulties in transitioning away from the mercury materials, and the oral health of Swedes did not collapse as the dire predictions had envisioned. Actually, the dental schools stopped teaching the use of mercury, and Sweden quickly became a healthier country for its environment, its citizens, and its future.

If other countries learn from the example of Sweden, the entire planet could benefit from a new level of health. However, since the world appears to have opted to gradually phase-down the use of dental mercury, this means that as a dental professional, you can wait to take action until you are told to do so, or you can protect the environment, your patients, and yourself immediately by not using amalgam in your practice. The Environmental Committee of the IAOMT has pioneered the safe and environmentally conscious dental practice and has encouraged and facilitated all members in bringing their practices into alignment with stringent protections for employees, the environment, as well as patients.


1.Pirrone, Nicola; Mason, Robert. Mercury Fate and Transport in the Global Atmosphere: Emissions, Measurements, and Models. (New York , 2009). http://books.google.com/books?id=mMVfbOQQeRMC&pg=PA166&lpg=PA166&dq=asgm+ecosystems&source=bl&ots=I1ZNKjc7r8&sig=AFNxft-Xe-c_VXeQUJjL_XbEE3E&hl=en&ei=t–cTunJO6Xq0gGhrr2hCQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBoQ6AEwAA#v=onepage&q=asgm%20ecosystems&f=false
2.Ibid.
3.United States Environmental Protection Agency. Mercury: Human Exposure, October 2010, 1. http://www.epa.gov/hg/exposure.htm
4.State of Connecticut Department of Public Health. A Woman’s Guide to Eating Fish Safely: Special Advice for Pregnant Women & Young Children, 2010, http://www.ct.gov/dph/lib/dph/environmental_health/eoha/pdf/womans_guide_-english_2010.pdf
5.United States Food and Drug Administration. What You Need to Know about Mercury in Fish and Shellfish, 2009. http://www.fda.gov/Food/ResourcesForYou/Consumers/ucm110591.htm
6.Ibid.
7.Fischer R. Assessing State and Local Regulations to Reduce Dental Mercury Emissions. Domestic Policy Subcommittee Oversight and Government Reform Committee. July 8, 2008.
8.New York Academy of Sciences. Pollution Prevention and Management Strategies for Mercury in the NY/NJ Harbor. June 2002. http://www.nyas.org/Publications/Annals/Detail.aspx?cid=8454dd76-8998-4ee7-b7a2-5a97f68c790c
9.United States Environmental Protection Agency. Mercury in Dental Amalgam. August 5, 2011. http://www.epa.gov/mercury/dentalamalgam.html
10.Hylander, Lars D. et al. “Mercury recovery in situ of four different amalgam separators.” Science of the Total Environment. 2006. http://www.sciencedirect.com/science/article/pii/S0048969705004961
11.Arenholt-Bindslev, D., et al., Mercury Levels and Discharge in Waste Water from Dental Clinics, Water Air Soil Pollution, 86(1-4):93-9 (1996). Abstract available at http://www.springerlink.com/content/pp65v404t276p450/
12.Royal College of Dental Surgeons in Ontario. “Amalgam Waste Disposal.” Standard of Practice. November 2003. www.rcdso.org
13.United States Environmental Protection Agency. Mercury in Dental Amalgam. August 5, 2011. http://www.epa.gov/mercury/dentalamalgam.html
14.Ibid.
15.Bender, Michael. “Facing up to the hazards of mercury tooth fillings.” A Report to the U.S. House of Representatives; Government Oversight Committee on Domestic Policy: Assessing State and Local Regulations to Reduce Dental Mercury Emissions. (Washington, DC: July 8, 2008). Available online at http://www.non-au-mercure-dentaire.org/_fichiers/submission_mercury_policy_project.pdf
16.Health Canada. The Safety of Dental Amalgam. (Ottawa, Ontario: report, 1996), 4. http://www.hc-sc.gc.ca/dhp-mps/alt_formats/hpfb-dgpsa/pdf/md-im/dent_amalgam-eng.pdf
17.Richardson GM, R Wilson, D Allard, C Purtill, S Douma and J Gravière. 2011. Mercury exposure and risks from dental amalgam in the US population, post-2000. Science of the Total Environment, DOI 10.1016/j.scitotenv.2011.06.035, 22-JUL-2011. Abstract available at http://www.sciencedirect.com/science/article/pii/S0048969711006607
18.Stone, ME, Cohen, ME, Debban, BA, “Mercury vapor levels in exhaust air from dental vacuum systems,” Dental Materials, 23 (5): 527-532, May 2007. Abstract available at http://www.sciencedirect.com/science/article/pii/S0109564106000881
19.Rubin PG, Yu M-H, “Mercury vapor in amalgam waste discharged from the dental office vacuum units.” Arch Environ Health 51(4):335-7, 1996 Jul-Aug. http://www.tandfonline.com/doi/abs/10.1080/00039896.1996.9936036
20.Institute of Environmental Medicine (Sweden). Karolinska Institute Report. IMM 1/92.
21.Rivola J, Krejci I, Imfeld T, Lutz F. “Cremation and the Environmental Mercury Burden.” Schweiz Monatsschr Zahnmed 100(11):1299-303, 1990.
22.Fdn for Toxic Free Dentistry, Dental and Health Facts Newsletter, 5(3), Sept 1992.
23.Bender, Michael. “Facing up to the hazards of mercury tooth fillings.” A Report to the U.S. House of Representatives; Government Oversight Committee on Domestic Policy: Assessing State and Local Regulations to Reduce Dental Mercury Emissions. (Washington, DC: July 8, 2008). Available online at http://www.non-au-mercure-dentaire.org/_fichiers/submission_mercury_policy_project.pdf
24.Ray, Carla. “Bio-cremation: Going green.” Channel 2 NBC. (September 26, 2011). Available online at http://www.nbc-2.com/story/15552561/bio-cremation
25.Kelly, Tom. “Cremation costs to rise as tooth fillings poison the living.” Daily Mail U.K. (January 2007). Available online at http://www.dailymail.co.uk/news/article-427368/Cremation-costs-rise-tooth-fillings-poison-living.html
26.Cornell, DeeDee. “Mercury emissions fuel cremation fight.” Los Angeles Times. (December 30, 2007). Available online at http://www.boston.com/news/nation/articles/2007/12/30/mercury_emissions_fuel_cremation_fight/?page=full
27.Chea, Terence. “Cremation pollution?: Neighbors nervous.” MSNBC and Associated Press. (1/16/2007). Available online at http://www.msnbc.msn.com/id/16656749/ns/us_news-environment/t/cremation-pollution-neighbors-nervous/
28.United Nations Environment Programme. Minamata Convention on Mercury. Geneva, Switzerland: United Nations Environment Programme. 2013. p. 23. http://www.mercuryconvention.org/Portals/11/documents/conventionText/Minamata%20Convention%20on%20Mercury_e.pdf
29.Northeast Natural Resource Center of the National Wildlife Federation and State of Connecticut Department of Environmental Protection. The Environmentally Responsible Dental Office: A Guide to Proper Waste Management in Connecticut Dental Offices. June 2000. http://www.ct.gov/deep/lib/deep/mercury/gen_info/NWF-CTdentalreport.pdf
30.State of Connecticut Department of Environmental Protection. Fillings: The Choices You Have. Mercury Amalgam and Other Filling Materials. Hartford, CT: Departmend of Environmental Protection. Revised May 2011. http://www.csda.com/docs/default-source/regulations/amalgam.pdf?sfvrsn=0
31.Nordic Council of Ministers. Treatment and Disposal of Mercury Waste: Strategic Elements Proposed by a Nordic Tema Nord 1999: 544. Copenhagen, Denmark: Nordic Council of Ministers. p. 28.
32.Edie Newsroom. “SWEDEN: mercury sniffer dogs clean up Swedish schools.” Edie.net Web site. (April 16, 1999). http://www.edie.net/news/0/SWEDEN-mercury-sniffer-dogs-clean-up-Swedish-schools/1001/

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ELECTRIC TEETH:
CHEMICAL REACTIONS IN THE MOUTH AND
THE PHENOMENON OF ORAL GALVANISM 2014

By John Kall, DMD, FAGD, MIAOMT, and Amanda Just

Introduction

When Jaro Pleva, PhD, published a study entitled “Corrosion and Mercury Release from Dental Amalgam” in 1989, he aptly noted that in order to accurately report on mercury releases from dental amalgam, “…specialist competence in the following fields is required: materials science,
corrosion/electrochemistry, toxicology, medicine/diagnostics, physical biology, analytical
chemistry.” 1

Not ironically, a number of years prior to that, Pleva, dentist Olle Redhe, DDS, and Mats Hanson, PhD and IAOMT Fellow, had communicated about oral galvanism with G. Wrangle’n, a professor of Technical Electrochemistry and Corrosion Science. At one point, Wrangle’n wrote to Redhe and Hanson, “The history of science shows that new, revolutionary theories often are met by ignorance and even persecution by established science. This reflects a serious defect in human intellect which someone ought to write a book about.”2

The comment by Wrangle’n is especially poignant because the science behind oral galvanism is an essential aspect of recognizing the hazards of dental mercury. In fact, Hanson suggested that it would be fitting for researchers to simply replace the term oral galvanism with the term mercury poisoning.3

The existence of oral galvanism can be easily explained; however, the factors that play into oral galvanism and its ensuing consequences make it a much more complex topic. Unfortunately, without this more detailed understanding of oral galvanism, the entire concept of dental mercury poisoning is missing a crucial part of its equation.

The cornerstones of oral galvanism: Demystifying the phenomenon of electric teeth

Suggesting that the mouth could be a battery and that teeth can be electric probably sounds blatantly bizarre to just about anyone who has not studied oral galvanism. Yet, the fact that such a situation can actually occur is quite elementary.

First, defining the technological term oral galvanism assists greatly in conveying information about this dental phenomenon. Galvanism is defined as “a direct current of electricity especially when produced by chemical action.” 4Thus, oral galvanism simply means electric currents produced by chemical action in the mouth.

Next, one must have a fundamental understanding of electricity in order to realize that circumstances in the human mouth could generate such currents. In the event one does not recall the lesson on the basics of electricity from their days in school, the MIT School of Engineering’s description of how a battery works provides a brief review:

There are three main components of a battery: two terminals made of different chemicals (typically metals), the anode and the cathode; and the electrolyte, which separates these terminals. The electrolyte is a chemical medium that allows the flow of electrical charge between the cathode and anode. When a device is connected to a battery—a light bulb or an electric circuit—chemical reactions occur on the electrodes that create a flow of electrical energy to the device.

More specifically: during a discharge of electricity, the chemical on the anode releases electrons to the negative terminal and ions in the electrolyte through what’s called an oxidation reaction. Meanwhile, at the positive terminal, the cathode accepts electrons, completing the circuit for the flow of electrons.5

Northwestern University also offers an explanation on battery operation. They specify that the battery consists of an anode (-), a cathode (+), and an electrolyte. Chemical reactions between these result in electrons congregating at the anode, creating an electrical disparity. The researchers note:

You can think of this difference as an unstable build-up of the electrons. The electrons want to rearrange themselves to get rid of this difference. But they do this in a certain way. Electrons repel each other and try to go to a place with fewer electrons. In a battery, the only place to go is to the cathode. But, the electrolyte keeps the electrons from going straight from the anode to the cathode within the battery. When the circuit is closed (a wire connects the cathode and the anode) the electrons will be able to get to the cathode.6

At this point, one might still be wondering about how this highly charged situation could possibly occur in the mouth. Considering all of the available options for dental materials, the accessibility to metals to serve as the anode and cathode in the oral cavity is abundant. For example, research from 2012 by Zohdi, Emami, and Shahverdi entitled “Galvanic Corrosion Behavior of Dental Alloys” listed the metals that serve as the base of commonly used dental alloy types, including gold, palladium, silver, cobalt, nickel, titanium, iron, and of course, mercury.7 The research also identifies additional elements used as ingredients in these alloys.

As another example, Pleva reported in his 1989 study, “Though the combination of gold and amalgam is the most frequent case of oral galvanic cell, galvanic corrosion can occur between many other metals used for dental restorations.” Pleva goes on to give an example of a stainless steel screwpost that impacted dental amalgam.8

Obviously, a mouth with any amount of metallic dental work has all the metals needed to produce chemical reactions, but saliva also plays a role, serving as the electrolyte, especially due to the contents of saliva, which can contain varying levels of calcium, magnesium, potassium, and acid.9 Zohdi et al. provide a simple explanation of the process: “In dentistry application, galvanic corrosion occurs when two or more dental prosthetic devices with dissimilar alloys come into contact while subjected to oral liquids like salvia; the difference between the corrosion potentials results in a flow of electric current between them.”10

A Swedish study from 1983 by Nordenström describes how other parts of the mouth can also play a role in oral galvanism:

Thus, in oral galvanism the intraoral ionic conducting branch, formed over the saliva between two electron conductors, may combine with one or several parallel-coupled, biological conducting branches in surrounding tissues. These branches, for instance, may be represented by blood vessels and interstitial channels… A galvanic current through the circuit can now develop between metals of different electric potential even when these metals are separated by a distance.11

Finally, an interesting aspect to emphasize here is that oral galvanism is widely accepted but marginally understood. There is general consensus that oral galvanism exists, as dental textbooks have included reference of it for decades.12 Therefore, most dental authorities acknowledge oral galvanism, and Health Canada has even stated that “new amalgam fillings should not be placed in contact with existing metal devices in the mouth, such as braces.”13 However, when it comes to fully taking heed of the consequences of oral galvanism, the evidence does not appear to have significantly altered dental practices.

Factors that influence chemical reactions in the mouth and the impact on patients

It is not surprising that the term oral galvanism is often used synonymously with the term galvanic corrosion. This is because a primary action of electrical currents in the mouth is to cause corrosion, similar to the rust that appears on batteries, cars, and other metallic objects. Indeed, it is typically accepted that electrical currents in the oral cavity result in more extreme corrosion of the dental materials and that this, in turn, can result in more metallic releases. Zohdi et al. explain: “The higher the corrosion rate of the alloy, the greater the metal ion release and the greater the risk of undesirable reactions in the mouth.”14

This potential for increased metallic releases has certainly been confirmed in the case of amalgam fillings,15 which are known to produce mercury vapor and particles,16 as well as free mercury droplets,17 during the corrosion process.

A gamut of factors can determine the rate of corrosion, and research has identified a number of situations that can increase corrosion, including the ones on this much abbreviated list:

  • the combination of gold and amalgam18,19
  • the different surfaces of the restoration20
  • the composition of saliva and dentin fluid21
  • biting, wear and tear, increase in temperature, and acidic and salty food22
  • “‘injury reactions’ at the interfaces between gingival or root canals and the restoration metals’”23
  • periodontitis or chronic periodontitis24

Similarly, a wide-range of symptoms from oral galvanism have been reported in patients. Galvanic currents have been associated with sharp pains, and galvanic corrosion has been linked to metallic tastes in the mouth, allergy, and irritation.25

Additionally, oral lesions,26 blackening of crevice surfaces,27 amalgam tattoos,28 and all of the symptoms related to mercury poisoning29 have been linked to oral galvanism from amalgam fillings.

Furthermore, the release of mercury particulate, which can occur due to oral galvanism and amalgam fillings, can cause releases of mercury with the potential to result in mercury-resistant and antibiotic-resistant microflora.30 Mercury particulate has also been suspected of being able to produce methylmercury in the mouth31,32,33,34 and in the gut.35,36 (Pregnant women and children are warned not to eat certain types of seafood due to methylmercury.)37

Conclusion

While oral galvanism has been studied for nearly a century, the number of dental alloys used since the 1980’s has noticeably increased,38 and more and more chemical combinations are occurring in the mouths of patients.

When it comes to oral galvanism, it is clear that established dental and medical practices have not yet embraced the science behind this phenomenon. In fact, as research continues to prove and examine human health risks caused by mixing different metals in the mouth, somehow the electric currents—and the denial over their intensity and consequences—continue to ensue.

At the same time, as biocompatibility is considered and utilized more often in dentistry, there is hope for the issue of oral galvanism to be resolved. The truth of this distinct possibility is evident in the recovery of some patients who have had dental materials harmful to their systems removed. While numerous studies have documented recovery of symptoms after safe amalgam removal, studies specifically about oral galvanism have likewise observed the improved health of some patients who had the incompatible, electricity-generating dental materials taken out of their mouths.39,40


 

1. Pleva J. Corrosion and mercury release from dental amalgam. J. Orthomol. Med. 1989; 4(3): 141-158.
2. Hanson M. Electrical problems in dental fillings. Bio-Probe Newsletter. November 1990, 7-10. (IAOMT).
3. Hanson M. Electrical problems in dental fillings. Bio-Probe Newsletter. November 1990, 7-10. (IAOMT).
4. Merriam-Webster Dictionary. Galvanism. Merriam-Webster Dictionary web site. http://www.merriam-webster.com/dictionary/galvanism . Accessed May 16, 2014.
5. Massachusetts Institute of Technology (MIT) Engineering Department. Ask an Engineer: How Does a Battery Work? Engineering Department at Massachusetts Institute of Technology (MIT) web site. http://engineering.mit.edu/ask/how-does-battery-work . Posted May 1, 2012. Accessed May 16, 2014.
6. Qualitative Reasoning Group at Northwestern University, Cognitive Systems Division of the Department of Electrical Engineering and Computer Science. How Do Batteries Work? Qualitative Reasoning Group at Northwestern University web site. http://www.qrg.northwestern.edu/projects/vss/docs/power/2-how-do-batteries-work.html . Accessed May 16, 2014.
7. Zohdi H, Emami M, Shahverdi HR. Chapter 7: Galvanic Corrosion Behavior of Dental Alloys. Environmental and Industrial Corrosion – Practice and Theoretical Aspects. 2012.
8. Pleva J. Corrosion and mercury release from dental amalgam. J. Orthomol. Med. 1989; 4(3): 141-158.
9. Ziff S, Ziff MF. Dentistry without Mercury. ChampionsGate, FL: IAOMT; 2014.
10. Zohdi H, Emami M, Shahverdi HR. Chapter 7: Galvanic Corrosion Behavior of Dental Alloys. Environmental and Industrial Corrosion – Practice and Theoretical Aspects. 2012.
11. Nordenström http://www.biologicaldentalhealth.com/dr-verigins-biodental-library/85.html
12. Phillips R.W. Skinner’s Science of Dental Materials (7th ed). Philadelphia, PA: W.B. Saunders Co., 1973. Cited in Ziff S, Ziff MF. Dentistry without Mercury. ChampionsGate, FL: IAOMT; 2014.
13. Health Canada. The Safety of Dental Amalgam. Ottawa, Ontario: Minister of Health; 1996.
14. Zohdi H, Emami M, Shahverdi HR. Chapter 7: Galvanic Corrosion Behavior of Dental Alloys. Environmental and Industrial Corrosion – Practice and Theoretical Aspects. 2012.
15. Ziff S, Ziff MF. Dentistry without Mercury. ChampionsGate, FL: IAOMT; 2014.
16. Schriever W, Diamond LE. Electromotive forces and electric currents caused by metallic dental fillings. J Dent Res. 1952. 31(2):205-228.
17. Schneider PE, Sarker NK. Mercury release from dispersalloy amalgam. IADR Abstract #630. 1982.
18. Hanson M. Mercury poisoning from corrosion of dental amalgam. Dr. David Howard web site. http://www.davidhoward.com.au/resources/article12.html . Accessed May 16, 2014.
19. Pleva J. Corrosion and mercury release from dental amalgam. J. Orthomol. Med. 1989; 4(3): 141-158.
20. Nordenström B. Biologically closed electric circuits: Clinical, experimental and theoretical evidence for an additional circulatory system. Ursus Medical AB. 1983.
21. Hanson M. Electrical problems in dental fillings. Bio-Probe Newsletter. November 1990, 7-10. (IAOMT).
22. Pleva J. Corrosion and mercury release from dental amalgam. J. Orthomol. Med. 1989; 4(3): 141-158.
23. Nordenström B. Biologically closed electric circuits: Clinical, experimental and theoretical evidence for an additional circulatory system. Ursus Medical AB. 1983.
24. Nordenström B. Biologically closed electric circuits: Clinical, experimental and theoretical evidence for an additional circulatory system. Ursus Medical AB. 1983.
25. Zohdi H, Emami M, Shahverdi HR. Chapter 7: Galvanic Corrosion Behavior of Dental Alloys. Environmental and Industrial Corrosion – Practice and Theoretical Aspects. 2012.
26. Bánóczy J, Roed-Petersen B, Pindborg JJ, Inovay J. Clinical and histologic studies on electrogalvanically induced oral white lesions. Oral Surgery, Oral Medicine, Oral Pathology. 1979; 48(4): 319-323.
27. Pleva J. Corrosion and mercury release from dental amalgam. J. Orthomol. Med. 1989; 4(3): 141-158.
28. Windham B. Oral galvanism and Electromagnetic Fields (EMF): factors along with mercury’s high volatility and extreme toxicity in significant exposure levels and oral effects from amalgam fillings. DAMS, Inc. web site. http://www.flcv.com/galv.html . Accessed May 16, 2014.
29. Hanson M. Electrical problems in dental fillings. Bio-Probe Newsletter. November 1990, 7-10. (IAOMT).
30. Summers AO, Wireman J, Vimy MJ, Lorscheider FL, Marshall B, Levy SB, Billard L. Mercury released from dental “silver” fillings provokes an increase in mercury-and antibiotic-resistant bacteria in oral and intestinal floras of primates. Antimicrobial agents and chemotherapy. 1993; 37(4):825-834.
31. Sellars WA, Sllars R, Liang L, Hefley JD. Methyl mercury in dental amalgams in the human mouth. Journal of Nutritional and Environmental Medicine. 1996; 6(1):33-36.
32. Heintze U, Edwardsson S, Derand T, Birkhed D. Methylation of mercury from dental amalgam and mercuric chloride by oral streptococci in vitro. European Journal of Oral Sciences. 1983; 91(2):150-152.
33. Wang J, Liu Z. In vitro study of streptococcus mutans in the plaque on the surface of amalgam fillings on the conversion of inorganic mercury to organic mercury. Shanghai Kou Qiang Yi Xue. 2002; 9(2):70-72.
34. Leistevuo J, Leistevuo T, Helenius H, Pyy L, Österblad M, Huovinen P, Tenovuo. Dental amalgam fillings and the amount of organic mercury in human saliva. Caries Research. 2001; 35(3):163-166.
35. Rowland IR, Grasso P, Davies MJ. The methylation of mercuric chloride by human intestinal bacteria. Cellular and Molecular Life Sciences. 1975; 31(9):1064-5.
36. Yannai S, Berdicevsky I, Duek L. Transformations of inorganic mercury by candida albicans and saccharomyces cerevisiae. Applied and Environmental Microbiology. 1991; 57(1):245-247.
37. United States Food and Drug Administration, United States Environmental Protection Agency. What You Need to Know about Mercury in Fish and Shellfish [brochure EPA-823-R-04-005]. Washington, D.C.: FDA and EPA; March 2004. http://www.fda.gov/Food/ResourcesForYou/Consumers/ucm110591.htm.
38. Zohdi H, Emami M, Shahverdi HR. Chapter 7: Galvanic Corrosion Behavior of Dental Alloys. Environmental and Industrial Corrosion – Practice and Theoretical Aspects. 2012.
39. Pleva J. Corrosion and mercury release from dental amalgam. J. Orthomol. Med. 1989; 4(3): 141-158.
40. Bánóczy J, Roed-Petersen B, Pindborg JJ, Inovay J. Clinical and histologic studies on electrogalvanically induced oral white lesions. Oral Surgery, Oral Medicine, Oral Pathology. 1979; 48(4): 319-323.

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IT’S IN THE GENES:
REACTIONS TO DENTAL AMALGAM MERCURY

By David Kennedy, DDS, MIAOMT and Amanda Just

Evaluating a person’s genetic traits as a risk of disease is being practiced more and more often, sometimes even at the request of the patient. Probably the most well-known example of this is testing for the BRCA gene mutation to identify those at high risk for breast cancer. This type of genetic testing has received publicity in recent years, especially when actress Angelina Jolie controversially opted for a mastectomy rather than taking a chance on her genetic potential for developing breast cancer.1

While sectors of the medical community and general public have yet not embraced the concept of genetic susceptibility, science is showing that, like breast cancer, issues with mercury can be traced to certain genetic traits.2 Although this innovation has been slow to be heeded and accepted on a wide-scale basis, it offers an exciting possibility for finding new methods to prevent a number of incurable diseases.

Perhaps the easiest way of understanding this concept as it relates to dental mercury is simply by considering a commonly-used argument to defend the use of amalgam fillings: Only some people claim to have a horrible reaction to dental mercury, but others appear to be healthy. If you think about such a statement, it actually sheds light on the factor of genetic susceptibility: Certain people have negative responses to dental amalgam because they are genetically predisposed.

In work headed by Dr. Diana Echeverria and colleagues at the Battelle Centers for Public Health and Education in Seattle, an association was demonstrated between a specific genetic marker, dental mercury, and neurobehavioral parameters.3 The marker, a polymorphism in a gene called CPOX4 (for coproporphyrinogen oxidase, exon 4), was linked to decreased visuomotor speed in response to mercury exposure and indicators of depression in dental professionals. Echeverria’s work has also pointed toward a link between the BDNF gene (brain-derived neurotropic factor) and mercury susceptibility.4

Furthermore, the CPOX4 genetic marker was identified as a factor for neurobehavioral issues in a study of children with dental amalgam tooth restorations by Dr. James Woods, Dr. Diana Echeverria, and others. The researchers noted, “…among boys, numerous significant interaction effects between CPOX4 and Hg [mercury] were observed spanning all 5 domains of neurobehavioral performance…These findings are the first to demonstrate genetic susceptibility to the adverse neurobehavioral effects of Hg [mercury] exposure in children.”5

Another area of genetic susceptibility that has merited scientific attention in relation to dental mercury is the APO-E4 (Apo-lipoprotein E4) genotype. A 2006 study found a correlation between individuals with APO-E4 and chronic mercury toxicity.6 The same study found that removal of dental amalgam fillings resulted in “significant symptom reduction,” and one of the symptoms listed was memory loss.

The APO-E4 genotype has also been associated with a higher risk for Alzheimer’s disease.7,8,9 Researchers have also noted, “The increased AD [Alzheimer’s disease] risk through APO-E4 might be caused by its reduced ability to bind heavy metals. Latest therapeutic approaches to the treatment of Alzheimer disease embrace pharmaceuticals which remove or bind metals from the brain.”10

Notably, one study, which found a connection between number of mercury fillings and neurotoxic effects for those with APOE genotype, explains, “APO-E genotyping warrants investigation as a clinically useful biomarker for those at increased risk of neuropathology, including AD [Alzheimer’s disease], when subjected to long-term mercury exposures…An opportunity could now exist for primary health practitioners to help identify those at greater risk and possibly forestall subsequent neurological deterioration.”11

Research has additionally shown that dental mercury fillings can potentially play a role in immune system problems for genetically predisposed patients. Whereas animal studies have established a connection between dental mercury and autoimmunity,12,13 human studies have confirmed that genetic susceptibility to reactions from dental mercury is potentially related to chronic fatigue syndrome,14 and multiple sclerosis, rheumatoid arthritis, and amyotrophic lateral sclerosis.15

Furthermore, scientific data has linked mercury and genetic traits to chemical sensitivities,16 autism,17,18 and Kawasaki’s disease,19 and research has also suggested that genetic transporters could be involved in the toxicokinetics of mercury.20

Yet, even with the recognition that genetic susceptibility plays a role in reactions to dental amalgam, research warns that there are most likely a variety of other factors tied into health risks of mercury as well. In addition to genetic predisposition, the number of amalgam fillings in the mouth,21,22,23,24,25,26,27,28,29,30,31,32,33 gender,34,35,36,37,38,39 dental plaque,40 selenium levels,41 exposure to lead,42,43,44,45 consumption of milk46,47 or alcohol,48 and other circumstances49 can play a role in each person’s unique response to mercury.

One of the most promising aspects of this new multi-factorial research in relation to health risks from dental amalgam is that this perspective offers science an opportunity to re-evaluate many diseases that are currently not well understood. It also demonstrates that research which fails to take into account variables such as genetic susceptibility is missing a major piece of the puzzle required to accurately assess health risks, prevention, treatment, and potential cures.


 

1. Angelina Jolie’s preventative mastectomy raised breast cancer awareness, but not knowledge. Huffington Post. December 27, 2013. http://www.huffingtonpost.com/2013/12/27/angelina-jolie-breast-cancer-awareness-knowledge_n_4474075.html
2. Richardson GM, Brecher RW, Scobie H, Hamblen J, Samuelian J, Smith C. Mercury vapour (Hg(0)): Continuing toxicological uncertainties, and establishing a Canadian reference exposure level. Regul Toxicol Pharmacol. 2009; 53(1):32-38.
3. Echeverria D, Woods JS, Heyer NJ, Rohlman D, Farin F, Li T, Garabedian CE. The association between a genetic polymorphism of coproporphyrinogen oxidase, dental mercury exposure and neurobehavioral response in humans. Neurotoxicol Teratol. 2006; 28(1):39-48.
4. Echeverria D, Woods JS, Heyer NJ, Rohlman DS, Farin FM, Bittner AC, Li T, Garabedian C. Chronic low-level mercury exposure, BDNF polymorphism, and associations with cognitive and motor function. Neurotoxicology and teratology. 2005; 27(6):781-796.
5. Woods JS, Heyer NJ, Echeverria D, Russo JE, Martin MD, Bernardo MF, Luis HS, Vaz L, Farin FM. Modification of neurobehavioral effects of mercury by a genetic polymorphism of coproporphyrinogen oxidase in children. Neurotoxicol Teratol. 2012; 34(5):513-21.
6. Wojcik DP, Godfrey ME, Christie D, Haley BE. Mercury toxicity presenting as chronic fatigue, memory impairment and depression: diagnosis, treatment, susceptibility, and outcomes in a New Zealand general practice setting: 1994-2006. Neuro Endocrinol Lett. 2006; 27(4):415-423.
7. Haley BE. The relationship of the toxic effects of mercury to exacerbation of the medical condition classified as Alzheimer’s disease. Medical Veritas. 2007; 4(2):1510–1524.
8. Mutter J, Naumann J, Sadaghiani C, Schneider R, Walach H. Alzheimer disease: mercury as pathogenetic factor and apolipoprotein E as a moderator. Neuro Endocrinol Lett. 2004; 25(5): 331-339.
9. Breitner J, Kathleen A. Welsh KA, Gau BA, McDonald WM, Steffens DC, Saunders AM, Kathryn M. Magruder KM et al. Alzheimer’s Disease in the National Academy of Sciences–National Research Council Registry of Aging Twin Veterans: III. Detection of Cases, Longitudinal Results, and Observations on Twin Concordance. Archives of Neurology. 1995; 52(8):763.
10. Mutter J, Naumann J, Schneider R, Walach H. Mercury and Alzheimer’s disease. Fortschr Neurol Psychiatr. 2007; 75(9):528-538. German.
11. Godfrey ME, Wojcik DP, Krone CA. Apolipoprotein E genotyping as a potential biomarker for mercury neurotoxicity. J Alzheimers Dis. 2003; 5(3):189-195.
12. Hultman P, Johansson U, Turley SJ, Lindh U, Enestrom S, Pollard KM. Adverse immunological effects and autoimmunity induced by dental amalgam and alloy in mice. FASEB J. 1994; 8(14):1183-90.
13. Weiner JA, Nylander M, Berglund F. Does mercury from amalgam restorations constitute a health hazard? Sci Total Environ. 1990; 99(1):1-22.
14. Stejskal VDM, Cederbrant K, Lindvall A, Forsbeck M. MELISA—an in vitro tool for the study of metal allergy. Toxicology in vitro. 1994; 8(5):991-1000.
15. Stejskal J, Stejskal VD. The role of metals in autoimmunity and the link to neuroendocrinology. Neuro Endocrinol Lett. 1999; 20(6):351-366.
16.Zamm A. Dental mercury: a factor that aggravates and induces xenobiotic intolerance. Journal of Orthomolecular Medicine. 1991; (6)2.
17. Bernard S, Enayati A, Redwood L, Roger H, Binstock T. Autism: a novel form of mercury poisoning. Med Hypotheses. 2001; 56(4):462-71.
18. Mutter J, Naumann J, Schneider R, Walach H, Haley B. Mercury and autism: accelerating evidence. Neuro Endocrinol Lett. 2005: 26(5):439-446.
19. Mutter J, Yeter D. Kawasaki’s disease, acrodynia, and mercury. Curr Med Chem. 2008; 15(28):3000-10.
20. Engström K, Ameer S, Bernaudat L, Drasch G, Baeuml J, Skerfving S, Bose-O’Reilly S, Broberg, K. Polymorphisms in genes encoding potential mercury transporters and urine mercury concentrations in populations exposed to mercury vapor from gold mining. Environmental Health Perspectives. 2013; 121(1): 85.
21. Krausß P, Deyhle M, Maier KH, Roller E, Weiß HD, Clédon P. Field study on the mercury content of saliva. Toxicological & Environmental Chemistry. 1997; 63, (1-4):29-46.
22. Geier DA, Kern JK, Geier MR. A prospective study of prenatal mercury exposure from dental amalgams and autism severity. Neurobiolgiae Experimentals Polish Neuroscience Society. 2009; 69(2): 189-197.
23. Eggleston DW, Nylander M. Correlation of dental amalgam with mercury in brain tissue. J Prosthet Dent. 1987; 58(6): 704-707.
24. Rothwell JA, Boyd PJ. Amalgam fillings and hearing loss. International Journal of Audiology. 2008; 47(12): 770-776.
25. Barregard L, Fabricius-Lagging E, Lundh T, Molne J, Wallin M, Olausson M, Modigh C, Sallsten G. Cadmium, mercury, and lead in kidney cortex of living kidney donors: impact of different exposure sources. Environ Res. 2010; 110(1): 47-54.
26. Richardson GM, Wilson R, Allard D, Purtill C, Douma S, Gravière J. Mercury exposure and risks from dental amalgam in the US population, post-2000. Science of the Total Environment. 2011; 409(20): 4257-4268.
27. Dunn JE, Trachtenberg FL, Barregard L, Bellinger D, McKinlay S. Scalp hair and urine mercury content of children in the northeast United States: the New England children’s amalgam trial. Environ Res. 2008; 107(1):79–88.
28. Dye BA, Schober SE, Dillon CF, Jones RL, Fryar C, McDowell M, et al. Urinary mercury concentrations associated with dental restorations in adult women aged 16–49 years: United States, 1999–2000. Occup Environ Med. 2005; 62(6):368–75.
29. Pesch A, Wilhelm M, Rostek U, Schmitz N, Weishoff-Houben M, Ranft U, et al. Mercury concentrations in urine, scalp hair, and saliva in children from Germany. J Expo Anal Environ Epidemiol. 2002; 12(4):252–8.
30. Bergdahl IA, Ahlqwist M, Barregard L, Björkelund C, Blomstrand A, Skerfving S, Sundh V, Wennberg M, Lissner L. Mercury in serum predicts low risk of death and myocardial infarction in Gothenburg women. Int Arch Occup Environ Health. 2013; 86(1): 71-77.
31. Geer LA, Persad MD, Palmer CD, Steuerwald AJ, Dalloul M, Abulafia O, Parsons PJ. Assessment of prenatal mercury exposure in a predominately Caribbean immigrant community in Brooklyn, NY. J Environ Monit. 2012; 14(3):1035-1043.
32. Gibicar D, Horvat M, Logar M, Fajon V, Falnoga I, Ferrara R, Lanzillotta E, Ceccarini C, Mazzolai B, Denby B, Pacyna J. Human exposure to mercury in the vicinity of chlor-alkali plant. Environ Res. 2009; 109(4): 355-367.
33. McGrother CW, Dugmore C, Phillips MJ, Raymond NT, Garrick P, Baird WO. Epidemiology: Multiple sclerosis, dental caries and fillings: a case-control study. Br Dent J. 1999; 187(5): 261-264.
34. Richardson GM, Brecher RW, Scobie H, Hamblen J, Samuelian J, Smith C. Mercury vapour (Hg(0)): Continuing toxicological uncertainties, and establishing a Canadian reference exposure level. Regul Toxicol Pharmicol. 2009; 53(1):32-38.
35. Rowland AS, Baird DD, Weinberg CR, Shore DL, Shy CM, Wilcox AJ. The effect of occupational exposure to mercury vapour on the fertility of female dental assistants. Occupat Environ Med. 1994; 51:28-34.
36. Haley BE. Mercury toxicity: genetic susceptibility and synergistic effects. Medical Vertias. 2005; 2(2): 535-542.
37. Woods JS, Heyer NJ, Echeverria D, Russo JE, Martin MD, Bernardo MF, Luis HS, Vaz L, Farin FM. Modification of neurobehavioral effects of mercury by a genetic polymorphism of coproporphyrinogen oxidase in children. Neurotoxicol Teratol. 2012; 34(5):513-21.
38. Gundacker C, Komarnicki G, Zödl B, Forster C, Schuster E, Wittmann K. Whole blood mercury and selenium concentrations in a selected Austrian population: Does gender matter? Sci Total Environ. 2006; 372(1): 76-86.
39. Watson GE, Evans K, Thurston SW, van Wijngaarden E, Wallace JM, McSorley EM, Bonham MP, Mulhern MS, McAfee AJ, Davidson PW, Shamlaye CF, Strain JJ, Love T, Zareba G, Myers GJ. Prenatal exposure to dental amalgam in the Seychelles Child Development Nutrition Study: Associations with neurodevelopmental outcomes at 9 and 30 months. Neurotoxicology. 2012.
40. Lyttle HA, Bowden GH. The level of mercury in human dental plaque and interaction in vitro between biofilms of streptococcus mutans and dental amalgam. Journal of Dental Research. 1993;72(9): 1320-1324.
41. Raymond LJ, Ralston NVC. Mercury: selenium interactions and health complications. Seychelles Medical and Dental Journal. 2004; 7(1): 72-77.
42. Haley BE. Mercury toxicity: genetic susceptibility and synergistic effects. Medical Vertias. 2005; 2(2): 535-542.
43. Haley BE. The relationship of the toxic effects of mercury to exacerbation of the medical condition classified as Alzheimer’s disease. Medical Veritas. 2007; 4(2):1510–1524.
44. Ingalls TH. Epidemiology, etiology, and prevention of multiple sclerosis. Hypothesis and fact. Am. J. Forensic Med. Pathol. 1983; 4(1):55-61.
45. Schubert J, Riley EJ, Tyler SA. Combined effects in toxicology—a rapid systematic testing procedure: Cadmium, mercury, and lead. Journal of Toxicology and Environmental Health, Part A Current Issues. 1978; 4(5-6):763-776.
46. Mata L, Sanchez L, Calvo, M. Interaction of mercury with human and bovine milk proteins. Biosci Biotechnol Biochem. 1997; 61(10): 1641-4.
47. Kostial K, Rabar I, Ciganovic M, Simonovic I. Effect of milk on mercury absorption and gut retention in rats. Bulletin of Environmental Contamination and Toxicology. 1979; 23(1): 566-571.
48. Hursh JB, Greenwood MR, Clarkson TW, Allen J, Demuth S. The effect of ethanol on the fate of mercury inhaled by man. JPET. 1980; 214(3):520-527.
49. Barregard L, Sallsten G, Jarvholm B. People with high mercury uptake from their own dental fillings. Occup Envir Med. 1995; 52(2): 124-128.

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‘TIL DEATH DO US PART:
DENTAL AMALGAM’S IMPACT ON THE ENVIRONMENT
FROM CREMATION AND BURIAL

By David Kennedy, DDS, MIAOMT, and Amanda Just

For nearly a century, health concerns have been raised about the mercury vapors emitted from dental amalgam fillings during a patient’s lifetime; however, the issue of what happens to mercury stored in the mouth of a patient with amalgam fillings after death is quickly becoming the subject of a new controversy due to a growing number of lawsuits and environmental concerns.

The United States Environmental Protection Agency (EPA) estimates there are currently over 1,000 tons of mercury in the mouths of Americans, which is more than half of all the mercury being used in the U.S. today.1 Unfortunately, given current funeral practices, almost all of the mercury still in the teeth of an individual at the time of death is eventually released back into the environment, where it can cause serious harm.

In order to understand how mercury pollution relates to the death of individuals with amalgam fillings, one must understand several basic qualities of this toxic heavy metal. First, when mercury is heated up, it vaporizes. While in this gaseous form, it is tasteless and odorless, but this airborne mercury can be taken in by other sources, such as soil, water, plants, and animals, including people. There, certain types of bacteria can transform it into methylmercury, which is regarded as a “deadly neurotoxin to humans and wildlife from its ability to cross the blood-brain barrier.” 2Methylmercury accumulates as it moves up the food chain, often from microorganisms to fish and then to humans. For this reason, pregnant women and children are advised not to eat certain types of seafood.3,4,5,

When a person with amalgam fillings is cremated, the dental mercury is obviously heated up and released as vapor from the crematorium. Exactly how much mercury emissions occur as a result of cremations with dental amalgam has been scrutinized. In a 2010 letter to the EPA from Congressman Dennis Kucinich,6 he describes the issue, while citing sources from the EPA and other authorities:

EPA estimated total mercury emitted as a byproduct of cremation of human remains to be around 0.3 tons per year. The official estimate is based entirely on a single test conducted at a single crematorium 10 years ago, and fails to explain the difference between the amount of mercury in fillings and the amount of mercury measured in crematorium emissions.7 However, an article published in 2007 authored by an EPA environmental scientist estimates mercury emissions from cremation at about 3 tons per year, ten times the earlier EPA estimate.8

Government leaders and researchers around the world have also considered the rates of mercury releases from crematoriums.9 A 2008 article from the Arctic Monitoring and Assessment Program and the United Nations Environment Programme Chemicals branch explains that dental amalgam leads to mercury releases from crematoriums. In Japan, where almost all citizens opt for cremation, a 2010 study reports that “the amount of mercury emitted by crematories will likely increase by 2.6-fold from 2007 to 2037.”10 Additionally, a report from Sweden estimated that in that country “as much as 620 pounds of dental amalgam mercury are released into the atmosphere each year from cremation,”11 while a report from the United States calculated, “In 1991, cremation of 320,372 bodies added an estimated 2,800 pounds of mercury into the atmosphere in the United States.”12

Although legislation has yet to be passed in the United States, Minnesota, Maine, Vermont, and Colorado have attempted to achieve regulations that would make removing amalgam fillings before cremation mandatory.13

Meanwhile, lawsuits filed by citizens fighting crematoriums in their neighborhoods are becoming more and more commonplace in the United States and other countries as well.14,15,16,17 A local CBS news report in California about a December 2013 lawsuit against a crematorium in East Oakland explains: “The suit seeks to compel the city to put the crematorium through a more rigorous permitting process that looks at how the facility would address potential pollutants such as mercury from dental fillings, as well as other contaminants emitted by the stacks.”18

A variety of trends suggest that controversy over mercury releases from amalgam fillings in crematoriums will continue to grow. An article by dental hygienists Christiansen and Larson notes that the number of cremations is increasing, and the elderly population is growing. They identify the fact that the number of amalgam fillings in the teeth of older Americans is likewise on the rise: “With the growing elderly population and better oral health measures, many people die with heavily restored mouths.”19 Citing statistics from the Minnesota Department of Health, they state that the “mouth of an elderly person has an average of 8.6 amalgam restorations.”20

One alternative to cremation with amalgam fillings is to recommend a traditional burial, but due to prices and religious practices, this is not a viable option for many people. More importantly, burying an individual with amalgam fillings means that the mercury is deposited directly into the soil. This means that whether a person is cremated or buried, the mercury is released back to the environment. A 2006 study by Hylander and Goodsite succinctly warns: “Amalgam fillings not replaced before death will cause emissions to air, soil, and water upon cremation or burial.”21

The same study also outlines the issue with suggesting that flue gas cleaning technology can reduce the amounts of mercury released from crematoriums: “The technology cannot recover all Hg [mercury] in the flue gases, and a certain pollution level of Hg [mercury] will still occur, contrary to if the fillings are removed before cremation.”22

The option of removing the amalgam fillings before the burial or cremation could significantly reduce emissions, but questions have been raised over who would perform this task, who would pay for it, and if safety measures would be applied to protect others from vapor releases that occur during the removal process.

Ending the use of dental amalgam would certainly help solve this problem in the future. However, given the 1000 tons of mercury currently implanted in the mouths of Americans, methods for handling this waste will be required for at least another century.

It is quite interesting that the option of safely removing amalgam fillings from patients that are still alive has not been seriously considered as a solution to this problem. First, such an action (as long as safety protocols are followed to limit mercury releases during removal) means that the mercury could be collected and accounted for at dental offices, where safe measures for handling waste could be enacted and applied. Second, since some patients report the reduction of symptoms after the removal of amalgam fillings,23,24,25,26,27,28,29,30,31,32,33,34,35,36 it means that many Americans might enjoy a healthier life.

In the meantime, when it comes to amalgam fillings, millions of individuals are likely to still have mercury in their mouths after they die. Beyond the potential to poison patients while they are alive, mercury wreaks havoc after death because it results in polluted environmental sites for hundreds of years after its initial release.37 This means that dental amalgam poses a threat to the environment and future generations long after we are gone and likewise, long after we stop using it.


1. United States Environmental Protection Agency. International Mercury Market Study and the Role and Impact of US Environmental Policy. 2004.
2. Christiansen P, Larson M. Mercury removal prior to cremation: a collaboration of dentistry and mortuary science to prevent environmental contamination. http://www.thefreelibrary.com/Mercury+removal+prior+to+cremation%3A+a+collaboration+of+dentistry+and…-a0216339047
3. United States Environmental Protection Agency. Mercury: Human Exposure, October 2010, 1. http://www.epa.gov/hg/exposure.htm
4. State of Connecticut Department of Public Health. A Woman’s Guide to Eating Fish Safely: Special Advice for Pregnant Women & Young Children, 2010, http://www.ct.gov/dph/lib/dph/environmental_health/eoha/pdf/womans_guide_-english_2010.pdf
5. United States Food and Drug Administration. What You Need to Know about Mercury in Fish and Shellfish, 2009. http://www.fda.gov/Food/ResourcesForYou/Consumers/ucm110591.htm
6. Kucinich D, Watson D. Dear Administrator Jackson [letter to Lisa P. Jackson of the Environmental Protection Agency]. Congress of the United States; Washington, D.C.: January 15, 2010.
7. Cited in Kucinich D, Watson D. Dear Administrator Jackson [letter to Lisa P. Jackson of the Environmental Protection Agency]. Congress of the United States: January 15, 2010 as
Appendix A: NEI Nonpoint HAP Source Estimates- Human Cremation, Footnote 3.
8. Cited in Kucinich D, Watson D. Dear Administrator Jackson [letter to Lisa P. Jackson of the Environmental Protection Agency]. Congress of the United States: January 15, 2010 as
Alexis Cain et al. “Substance Flow Analysis of Mercury Intentionally Used in Products in the United States,” Journal of Industrial Ecology, Volume 11, Number 3 (2007).
9. Cited in Takaoka M, Oshita K, Takeda N, Morisawa S. Mercury emission from crematories in Japan. Atmospheric Chemistry and Physics. 2010; 10(8): 3665-3671 as
Arctic Monitoring and Assessment Programme (AMAP) and UNEP Chemicals: Technical Background Report to the
Global Atmospheric Mercury Assessment, online available at http://www.chem.unep.ch/mercury/Atmospheric Emissions/Atmospheric emissions mercury.htm, 2008.
10. Takaoka M, Oshita K, Takeda N, Morisawa S. Mercury emission from crematories in Japan. Atmospheric Chemistry and Physics. 2010; 10(8): 3665-3671.
11. Institute of Environmental Medicine (Sweden). Karolinska Institute Report. IMM 1/92.
12. Fdn for Toxic Free Dentistry, Dental and Health Facts Newsletter, 5(3), Sept 1992.
13. Christiansen P, Larson M. Mercury removal prior to cremation: a collaboration of dentistry and mortuary science to prevent environmental contamination. http://www.thefreelibrary.com/Mercury+removal+prior+to+cremation%3A+a+collaboration+of+dentistry+and…-a0216339047
14. Ray, Carla. “Bio-cremation: Going green.” Channel 2 NBC. (September 26, 2011). Available online at http://www.nbc-2.com/story/15552561/bio-cremation
15. Kelly, Tom. “Cremation costs to rise as tooth fillings poison the living.” Daily Mail U.K. (January 2007). Available online at http://www.dailymail.co.uk/news/article-427368/Cremation-costs-rise-tooth-fillings-poison-living.html
16. Cornell, DeeDee. “Mercury emissions fuel cremation fight.” Los Angeles Times. (December 30, 2007). Available online at http://www.boston.com/news/nation/articles/2007/12/30/mercury_emissions_fuel_cremation_fight/?page=full
17. Chea, Terence. “Cremation pollution?: Neighbors nervous.” MSNBC and Associated Press. (1/16/2007). Available online at http://www.msnbc.msn.com/id/16656749/ns/us_news-environment/t/cremation-pollution-neighbors-nervous/
18. Culross M. Lawsuit alleges East Oakland air too polluted to allow crematorium. 5 KPIX CBS San Francisco. December 12, 2013. http://sanfrancisco.cbslocal.com/2013/12/12/lawsuit-alleges-east-oakland-air-too-polluted-to-allow-crematorium/
19. Cited in Christiansen P, Larson M. Mercury removal prior to cremation: a collaboration of dentistry and mortuary science to prevent environmental contamination. http://www.thefreelibrary.com/Mercury+removal+prior+to+cremation%3A+a+collaboration+of+dentistry+and…-a0216339047 as
American Dental Hygienists’ Association. Dental characteristics of the older adult. Available at http://www.adha.org/CE_courses/course11/ characteristics.htm. Accessed Apr. 2009.
20. Cited in Christiansen P, Larson M. Mercury removal prior to cremation: a collaboration of dentistry and mortuary science to prevent environmental contamination. http://www.thefreelibrary.com/Mercury+removal+prior+to+cremation%3A+a+collaboration+of+dentistry+and…-a0216339047 as
Minnesota Department of Health. Deaths and cremations by year. Mortuary Science Program. 2006; 1-9.
21. Hylander, L. D., & Goodsite, M. E. Environmental costs of mercury pollution. Science of the Total Environment. 2006; 368(1), 352-370.
22. Hylander, L. D., & Goodsite, M. E. Environmental costs of mercury pollution. Science of the Total Environment. 2006; 368(1), 352-370.
23. Lindqvist B, Mörnstad H. Effects of removing amalgam fillings from patients with diseases affecting the immune system. Medical Science Research. 1996; 24(5):355-356.
24. Siblerud RL. A comparison of mental health of multiple sclerosis patients with silver/mercury dental fillings and those with fillings removed. Psychol Rep. 1992; 70(3pt 2):1136-51.
25. Huggins HA, Levy TE. Cerebrospinal fluid protein changes in multiple sclerosis after dental amalgam removal. Altern Med Rev. 1998; 3(4): 295-300.
26. Siblerud RL, Kienholz E. Evidence that mercury from silver dental fillings may be an etiological factor in multiple sclerosis. The Science of the Total Environment. 1994; 142(3): 191-205.
27. Sterzl I, Prochazkova J, Hrda P, Matucha P, Stejskal VD. Mercury and nickel allergy: risk factors in fatigue and autoimmunity. Neuroendocrinol Lett. 1999; 20(3-4):221-228.
28. Stejskal I, Danersund A, Lindvall A, Hudecek R, Nordman V, Yaqob A, Mayer W, Bieger W, Lindh U. Metal-specific lymphocytes: biomarkers of sensitivity in man. Neuroendocrinol Lett. 1999; 20(5): 289-298.
29. Redhe O, Pleva J. Recovery of amyotrophic lateral sclerosis and from allergy after removal of dental amalgam fillings. Int J Risk & Safety in Med. 1994; 4(3): 229-236.
30. Prochazkova J, Sterzl I, Kucerkova H, Bartova J, Stejskal VDM. The beneficial effect of amalgam replacement on health in patients with autoimmunity. Neuroendocrinology Letters. 2004; 25(3): 211-218.
31. Hanson, M. Health and amalgam removal: a meta-analysis of 25 studies. Tf-bladet Bull of the Swedish Association of Dental Mercury Patients. Tf-bladet no. 2 2004 and SOU 2003:53 appendix 10, Sw. Dept. of Health. 204-216.
32. Tomka M, Machovkova A, Pelclova D, Petanova J, Arenbergerova M, Prochazkova J. Orofacial granulomatosis associated with hypersensitivity to dental amalgam. Science Direct. 2011; 112(3):335-341.
33. Zamm AV. Candida albicans therapy. Is there ever an end to it? Dental mercury removal: an effective adjunct.” J. Orthomol. Med. 1986; 1(4): 261-266.
34. Sjursen TT, Lygre GM, Dalen K, Helland V, Laegreid T, Svahn J, Lundekvam BF, Bjorkman L. Changes in health complaints after removal of amalgam fillings. Journal of Oral Rehabilitation. 2011; 38(11): 835-848.
35. Wojcik DP, Godfrey ME, Christie D, Haley BE. Mercury toxicity presenting as chronic fatigue, memory impairment and depression: diagnosis, treatment, susceptibility, and outcomes in a New Zealand general practice setting: 1994-2006. Neuro Endocrinol Lett. August 2006; 27(4): 415-423.
36. Laine J, Kalimo K, Forssell H, Happonen R. Resolution of oral lichenoid lesions after replacement of
amalgam restorations in patients allergic to mercury compounds. JAMA. 1992; 267(21):2880.
37. Pirrone, Nicola; Mason, Robert. Mercury Fate and Transport in the Global Atmosphere: Emissions, Measurements, and Models. ( New York , 2009). http://books.google.com/books?id=mMVfbOQQeRMC&pg=PA166&lpg=PA166&dq=asgm+ecosystems&source=bl&ots=I1ZNKjc7r8&sig=AFNxft-Xe-c_VXeQUJjL_XbEE3E&hl=en&ei=t–cTunJO6Xq0gGhrr2hCQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBoQ6AEwAA#v=onepage&q=asgm%20ecosystems&f=false


 

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DENTAL AMALGAM: A HISTORY OF CONTROVERSY

By David Kennedy, DDS, MIAOMT, and Amanda Just

One of the first reports documenting the dangers of using mercury amalgam in dentistry dates back to 1841. At that time, a committee of the American Society of Dental Surgeons, which was the first U.S. dental group, warned that amalgam was not safe.1 This report marked the beginning of a time period referred to as the “Amalgam War” due to the many debates and arguments that ensued over the issue of dental mercury. The Amalgam War can be viewed as a civil war within the field of dentistry, as both sides fought viciously to prove their point. The New York Dental Society even expelled or forced resignation from members who would not pledge to be amalgam-free.2

Notable examples of evidence against amalgam from this time period include a report from Dr. Amos Westcott warning that dental mercury could cause issues with the stomach and with gold fillings, a case study published in the American Dental Review of a patient whose health improved after amalgam removal, and the recommendation from Dr. Elisha Townsend, formerly a renowned proponent of amalgam, that the use of dental mercury should be avoided.3

By 1856, the American Society of Dental Surgeons had disbanded because of the Amalgam War, and in 1859, the American Dental Association (ADA), a group who supported the use of amalgam, became the nation’s new dental society.

However, concerns about dental amalgam continued. A July 1873 article in the Chicago Medical Journal by Dr. Payne warned of the “poisoning of thousands of people all over the world from corrosive sublimate generated in the mouth from amalgam plugs in the teeth; neither chlorella, smallpox, or any malarious disease [is] doing more injury in the world than this poison.”4

Meanwhile, in 1867, the St. Louis Odontological Society recognized health risks from amalgam fillings and voted not to use them,5 and in 1878, the Canada Lancet noted that the use of dental mercury “is radically wrong, and should not be ventured upon if the patient’s welfare is to be considered.”6

Additionally, based on a series of experiments, Dr. E. Talbot warned that “all amalgams will send off the vapor of mercury.”7 His work was published in the Ohio State Journal of Dental Science in 1882.

Equally important was Dr. J. Tuthill’s research entitled “Mercurial necrosis resulting from amalgam fillings,” which was published in The Brooklyn Medical Journal in 1898. Dr. Tuthill read his work, including a number of case studies, before a medical society, and in it he passionately stated:

In presenting this subject to the society for consideration, I want to show that by the use of amalgam in filling teeth there is a possibility of mercurial poisoning, which seriously affects the nerve centers, impairs locomotion by heaviness of limb and stiffness of joint, gives rise to obstinate diseases of the skin, and makes a mental wreck of its victim, whose imaginations and hallucinations are more than my pen can describe.8

Dr. Tuthill and others continued to fight the use of amalgam, and the debate over dental mercury continued into the twentieth century, when scientific progress allowed for many more studies to prove that mercury remains a toxic threat even when it is amalgamized and placed into teeth.

In one of the first studies to measure the amount of dental mercury vapor emitted from fillings, German chemist Alfred Stock shared evidence that mercury vapor is released from amalgam fillings in amounts significant enough to produce adverse health impacts. Stock himself suffered mercury poisoning, and his research appeared in a series of papers published in German scientific journals. Based on his data and experiences, in The Dangerousness of Mercury Vapor, Dr. Stock declared in 1926 that the introduction of mercury in amalgam fillings was “a nasty sin against humanity.”9

Because of new technology and scientific advancements, modern studies have been able to more accurately test issues related to dental amalgam mercury. Moreover, the increase in the number of studies being conducted has resulted in the development of research designed to evaluate specific risks related to mercury exposure from dental amalgam. Some of the areas of research addressed in recent scientific literature include

  • dental office/occupational exposure to mercury10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40
  • mercury vapor from fillings41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62
  • mercury vapor increase from number of fillings, chewing, teeth-grinding, brushing, dental treatments, and hot liquids63,64,65,66,67,68,69,70,71,72
  • genetic traits impacting mercury response73,74,75,76,78,79
  • fetal and infant exposure to mercury via maternal dental mercury amalgam80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95
  • mercury excreted in breast milk of mothers with dental mercury amalgam fillings, increasing with the number of amalgam fillings96,97,98,99
  • children100,101,102,103,104,105,106,107,108,109
  • allergy to mercury110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127
  • patients with autoimmune disorders/immunodeficiency128,129,130,131,132,133,134
  • patients with kidney disease135,136,137,138,139
  • patients with multiple sclerosis140,141,142,143
  • patients with oral lichenoid reaction144,145,146,147,148,149,150 and oral lichen planus151,152,153

While authorities continue to debate the use of amalgam, which they have been doing for over a century, science continues to prove that using a toxic material in people’s teeth can have serious health consequences. As the controversy over amalgam still rages, a famous quote from philosopher Arthur Schopenhauer offers an interesting analogy as to why it is taking so long to end the use of dental mercury: “All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident.”


1.Hyson Jr, JM. Amalgam: its history and perils. CDA. JOURNAL. 2006; 34(3):215-229.
2.Tuthill, JY. “Mercurial necrosis resulting from amalgam fillings.” The Brooklyn Medical Journal. 1898; XII:725-742.
3.Hyson Jr, JM. Amalgam: its history and perils. CDA. JOURNAL. 2006; 34(3):215-229.
4.Quoted in Tuthill, JY. “Mercurial necrosis resulting from amalgam fillings.” The Brooklyn Medical Journal. 1898; XII: 12:740.
5.Hyson Jr, JM. Amalgam: its history and perils. CDA. JOURNAL. 2006; 34(3):215-229.
6.Quoted in Hyson Jr, JM. Amalgam: its history and perils. CDA. JOURNAL. 2006; 34(3):215-229.
7.Talbot ES. The chemistry and physiological action of mercury as used in amalgam fillings. The Ohio State J. Dent.Sci. 1882; 2(1): 1-12.
8.Tuthill, JY. “Mercurial necrosis resulting from amalgam fillings.” The Brooklyn Medical Journal. 1898; XII:740.
9.Stock A. [Zeitschrift fuer angewandte Chemie, 29. Jahrgang, 15. April 1926, Nr. 15, S. 461-466, Die Gefaehrlichkeit des Quecksilberdampfes, von Alfred Stock (1926).] The Dangerousness of Mercury Vapor. Translated by Birgit Calhoun. http://www.stanford.edu/~bcalhoun/AStock.htm
10.Moen BE, Hollund BE, Riise T. Neurological symptoms among dental assistants: a cross-sectional study. Journal of Occupational Medicine and Toxicology. 2008: 3(1):10.
11.Nylander M, Friberg L, Eggleston D, Bjorkman L. Mercury accumulation in tissues from dental staff and controls in relation to exposure. Swed Dent J. 1989; 13(6): 235-236.
12.Herber RF, de Gee AJ, Wibowo AA. Exposure of dentists and assistants to mercury: mercury levels in urine and hair related to conditions of practice. Community Dent Oral Epidemiol. 1988; 16(3): 153-158.
13.Echeverria D, Heyer N, Martin MD, Naleway CA, Woods JS, Bittner AC. Behavioral effects of low-level exposure to Hg0 among dentists. Neurotoxicol Teratol. 1995; 17(2):161-8.
14.Rowland AS, Baird DD, Weinberg CR, Shore DL, Shy CM, Wilcox AJ. The effect of occupational exposure to mercury vapour on the fertility of female dental assistants. Occupat Environ Med. 1994; 51:28-34.
15.Shapiro IM, Cornblath DR, Sumner AJ, Sptiz LK, Uzzell B, Ship II, Bloch P. Neurophysiological and neuro-psychological function in mercury-exposed dentists. Lancet. 1982; 319(8282): 1447-1150.
16.Richardson GM, Brecher RW, Scobie H, Hamblen J, Samuelian J, Smith C. Mercury vapour (Hg(0)): Continuing toxicological uncertainties, and establishing a Canadian reference exposure level. Regul Toxicol Pharmicol. February 2009; 53(1):32-38.
17.Mutter J. Is dental amalgam safe for humans? The opinion of the scientific committee of the European Commission. Journal of Occupational Medicine and Toxicology. 2011; 6:2.
18.Ngim CH, Foo SC, Boey KW, Jeyaratnem J. Chronic neurobehavioural effects of elemental mercury in dentists.
Br J Ind Med. 1992; 49(11):782-790.
19.Cook TA, Yates PO. Fatal mercury intoxication in a dental surgery assistant. British Dental Journal. 1969; 127(12):553-5.
20.Sikorski R, Juszkiewicz T, Paszkowski T, Szprengier-Juszkiewicz T. Women in dental surgeries: reproductive hazards in exposure to metallic mercury. International Archives of Occupational and Environmental Health. September 1987; 59(6): 551-557.
21.White RR, Brandt RL. Development of mercury hypersensitivity among dental students. JADA. 1976; 92(6):1204-7.
22.Nimmo A, Werley MS, Martin JS, Tansy MF. Particulate inhalation during the removal of amalgam restorations. J Prosth Dent. 1990; 63(2):228-33.
23.Cooper GS, Parks CG, Treadwell EL, St Clair EW, Gilkeson GS, Dooley MA. Occupational risk factors for the development of systemic lupus erythematosus. J Rheumatol. 2004; 31(10): 1928-1933.
24.de Oliveira MT, Pereira JR, Ghizoni JS, Bittencourt ST, Molina GO. Effects from exposure to dental amalgam on systemic mercury levels in patients and dental school students. Photomed Laser Surg. 2010; 28(S2): S-111.
25.Fabrizio E, Vanacore N, Valente M, Rubino A, Meco G. High prevalence of extrapyramidal signs and symptoms in a group of Italian dental technicians. BMC Neurol. 2007; 7(1): 24.
26.Goodrich JM, Wang Y, Gillespie B, Werner R, Franzblau A, Basu N. Methylmercury and elemental mercury differentially associate with blood pressure among dental professionals. Int J Hyg Environ Health. 2013; 216(2): 195-201.
27.Hilt B, Svendsen K, Syversen T, Aas O, Qvenild T, Sletvold H, Melø I. Occurrence of cognitive symptoms in dental assistants with previous occupational exposure to metallic mercury. Neurotoxicology. 2009; 30(6): 1202-1206.
28.Kanerva L, Lahtinen A, Toikkanen J, Forss H, Estlander T, Susitaival P, Jolanki R. Increase in occupational skin diseases of dental personnel. Contact Dermatitis. 1999; 40(2): 104-108.
29.Karahalil B, Rahravi H, Ertas N. Examination of urinary mercury levels in dentists in Turkey. Hum Exp Toxicol. 2005; 24(8): 383-388.
30.Lönnroth EC, Shahnavaz H. Amalgam in dentistry. A survey of methods used at dental clinics in Norrbotten to decrease exposure to mercury vapour. Swed Dent J. 1995; 19(1-2): 55.
31.Lee JY, Yoo JM, Cho BK, Kim HO. Contact dermatitis in Korean dental technicians. Contact Dermatitis. 2001; 45(1), 13-16.
32.Martin MD, Naleway C, Chou HN. Factors contributing to mercury exposure in dentists. J Am Dent Assoc. 1995; 126(11): 1502-1511.
33.Mumtaz R, Khan AA, Noor N, Humayun S. Amalgam use and waste management by Pakistani dentists: an environmental perspective. East Mediterr Health J. 2010; 16(3).
34.Olfert SM. Reproductive outcomes among dental personnel: a review of selected exposures. J Can Dent Assoc. 2006; 72(9): 821.
35.Pérez-Gómez B, Aragonés N, Gustavsson P, Plato N, López-Abente G, Pollán, M. Cutaneous melanoma in Swedish women: occupational risks by anatomic site. Am J Ind Med. 2005; 48(4): 270-281.
36.Parsell DE, Karns L, Buchanan WT, Johnson RB. Mercury release during autoclave sterilization of amalgam. J Dent Educ. 1996; 60(5): 453-458.
37.Roberts HW, Leonard D, Osborne J. Potential health and environmental issues of mercury-contaminated amalgamators. J Am Dent Assoc. 2001; 132(1): 58-64.
38.Zahir F, Rizwi SJ, Haq SK, Khan RH. Low dose mercury toxicity and human health. Environ Toxicol Pharmacol. 2005; 20(2): 351-360.
39.Rowland AS, Baird DD, Weinberg CR, Shore DL, Shy CM, Wilcox AJ. The effect of occupational exposure to mercury vapour on the fertility of female dental assistants. Occupat Environ Med. 1994; 51:28-34.
40.Sikorski R, Juszkiewicz T, Paszkowski T, Szprengier-Juszkiewicz T. Women in dental surgeries: reproductive hazards in exposure to metallic mercury. International Archives of Occupational and Environmental Health. 1987; 59(6): 551-557.
41.Richardson GM, Brecher RW, Scobie H, Hamblen J, Samuelian J, Smith C. Mercury vapour (Hg(0)): Continuing toxicological uncertainties, and establishing a Canadian reference exposure level. Regul Toxicol Pharmicol. February 2009; 53(1):32-38.
42.Al-Saleh I, Al-Sedairi A. Mercury (Hg) burden in children: The impact of dental amalgam. Sci Total Environ. 2011; 409(16):3003-3015.
43.Nylander M, Friberg L, Lind B. Mercury concentrations in the human brain and kidneys in relation to exposure from dental amalgam fillings. Swed Dent J. 1987; 11(5): 179-187.
44.Mortada WL, Sobh MA, El-Defrawi, MM, Farahat SE. Mercury in dental restoration: is there a risk of nephrotoxity? J Nephrol. 2002; 15(2): 171-176.
45.Molin M, Bergman B, Marklund SL, Schutz A, Skerfving S. Mercury, selenium, and glutathione peroxidase before and after amalgam removal in man. Acta Odontol Scand. 1990; 48(3): 189-202.
46.Redhe O, Pleva J. Recovery of amyotrophic lateral sclerosis and from allergy after removal of dental amalgam fillings. Int J Risk & Safety in Med. 1994; 4(3): 229-236.
47.Godfrey ME, Wojcik DP, Krone CA. Apolipoprotein E genotyping as a potential biomarker for mercury toxicity. Journal of Alzheimer’s Disease. 2003; 5(3): 189-195.
48.Summers AO, Wireman J, Vimy MJ, Lorscheider FL, Marshall B, Levy SB, Bennet S, Billard L. Mercury released from dental ‘silver’ fillings provokes an increase in mercury- and antibiotic- resistant bacteria in oral and intestinal flora of primates. Antimicrob Agents and Chemother. 1993; 37(4): 825-834.
49.Fredin B. The distribution of mercury in various tissues of guinea-pigs after application of dental amalgam fillings (a pilot study). Sci Total Environ. 1987; 66: 263-268.
50.Danscher G, Horsted-Bindslev P, Rungby J. Traces of mercury in organs from primates with amalgam fillings. Ex Mol Pathol. June 1990; 52(3): 291-299.
51.Snapp KR, Boyer DB, Peterson LC, Svare CW. The contribution of dental amalgam to mercury in blood. J Dent Res. 1989; 68(5):780–5.
52.Vimy MJ, Lorscheider FL. Intra-oral air mercury released from dental amalgam. J Den Res. 1985; 64(8):1069-71.
53.Vimy MJ, Lorscheider FL: Serial measurements of intra-oral air mercury; Estimation of daily dose from dental amalgam. J Dent Res. 1985; 64(8):1072-5.
54.Vimy MJ, Luft AJ, Lorscheider FL. Estimation of mercury body burden from dental amalgam computer simulation of a metabolic compartment model. J. Dent. Res. 1986; 65(12):1415-1419.
55.Hahn LJ, Kloiber R, Leininger RW, Vimy MJ, Lorscheider FL. Whole-body imaging of the distribution of mercury released from dental fillings into monkey tissues. FASEB J. 1990; 4(14): 3256-3260.
56.Boyd ND, Benediktsson H, Vimy MJ, Hooper DE, Lorscheider FL. Mercury from dental “silver” tooth fillings impairs sheep kidney function. Am J Physiol. 1991; 261(4 Pt 2):R1010-4.
57.Hanson M, Pleva J. The dental amalgam issue: a review. Experientia. 1991; 47(1): 9-22.
58.Apostoli P, Cortesi I, Mangili A, Elia G, Drago I, Gagliardi T, Soleo L, Valente T, Sciarra GF, Aprea C, Ronchi A, Minoia C. Assessment of reference values for mercury in urine: the results of an Italian polycentric study. Sci Total Environ. 2002; 289(1): 13-24.
59.Barregård L. Biological monitoring of exposure to mercury vapor. Scand J Work Environ Health. 1993: 45-49.
60.Fredin B, Krabisch L. In vitro investigation of the possible influence of inorganic mercury and hydrogen peroxide on the formation of peroxides in a polyunsaturated fatty acid system (linoleic acid). Int J Risk Saf Med. 1993; 4(1): 19-25.
61.Martin MD, Naleway C, Chou HN. Factors contributing to mercury exposure in dentists. J Am Dent Assoc. 1995; 126(11): 1502-1511.
62.Mutter J, Naumann J. Mercury and the risk of myocardial infarction. N Engl J Med. 2003; 348(21):2151-4.
63.Vimy MJ, Lorscheider FL. Intra-oral air mercury released from dental amalgam. J Den Res. 1985; 64(8):1069-71.
64.Vimy MJ, Lorscheider FL: Serial measurements of intra-oral air mercury; Estimation of daily dose from dental amalgam. J Dent Res. 1985; 64(8):1072-5.
65.Gay DD, Cox RD, Reinhardt JW. Chewing releases mercury from fillings. Lancet. 1979; 313(8123):985-6.
66.Abraham JE, Svare CW, Frank CW. The effect of dental amalgam restorations on blood mercury levels. J Dent Res. 1984; 63(1):71-3.
67.Nimmo A, Werley MS, Martin JS, Tansy MF. Particulate inhalation during the removal of amalgam restorations. J Prosth Dent. 1990; 63:228-33.
68.Dunn JE, Trachtenberg FL, Barregard L, Bellinger D, McKinlay S. Scalp hair and urine mercury content of children in the northeast United States: the New England children’s amalgam trial. Environ Res. 2008; 107(1):79–88.
69.Isacsson G, Barregard L, Selden A, Bodin L. Impact of nocturnal bruxism on mercury uptake from dental amalgams. Eur J Oral Sci. 1997; 105(3):251–7.
70.Sallsten G, Thoren J, Barregard L, Schutz A, Skarping G. Long-term use of nicotine chewing gum and mercury exposure from dental amalgam fillings. J Dent Res. 1996; 75(1):594–8.
71.Bjorkman L, Lind B. Factors influencing mercury evaporation rate from dental amalgam fillings. Scand J Dent Res. 1992; 100(6):354–60.
72.Fredin B. Mercury release from dental amalgam fillings. Int J Risk Saf Med. 1994; 4(3): 197-208.
73.Richardson, GM, Brecher RW, Scobie H, Hamblen J, Samuelian J, Smith C. Mercury vapour (Hg(0)): Continuing toxicological uncertainties, and establishing a Canadian reference exposure level. Regul Toxicol Pharmicol. 2009; 53(1):32-38.
74.Godfrey ME, Wojcik DP, Krone CA. Apolipoprotein E genotyping as a potential biomarker for mercury toxicity. Journal of Alzheimer’s Disease. 2003; 5(3): 189-195.
75.Wojcik DP, Godfrey ME, Christie D, Haley BE. Mercury toxicity presenting as chronic fatigue, memory impairment and depression: diagnosis, treatment, susceptibility, and outcomes in a New Zealand general practice setting: 1994-2006. Neuro Endocrinol Lett. 2006; 27(4): 415-423.
76.Weiner JA, Nylander M, Berglund F. Does mercury from amalgam restorations constitute a health hazard? Sci Total Environ. 1990; 99(1-2):1-22.
77.Echeverria D, Woods JS, Heyer NJ, Rohlman D, Farin F, Li T, Garabedian CE. The association between a genetic polymorphism of coproporphyrinogen oxidase, dental mercury exposure and neurobehavioral response in humans. Neurotoxicol Teratol. 2006; 28(1):39-48.
78.Mutter J, Naumann J, Sadaghiani C, Schneider R, Walach H. Alzheimer disease: mercury as pathogenetic factor and apolipoprotein E as a moderator. Neuro Endocrinol Lett. 2004; 25(5): 331-339.
79.Woods JS, Heyer NJ, Echeverria D, Russo JE, Martin MD, Bernardo MF, Luis HS, Vaz L, Farin FM. Modification of neurobehavioral effects of mercury by a genetic polymorphism of coproporphyrinogen oxidase in children. Neurotoxicol Teratol. 2012; 34(5):513-21.
80.Palkovicova L, Ursinyova M, Masanova V, Yu Z, Hertz-Picciotto I. Maternal amalgam dental fillings as the source of mercury exposure in developing fetus and newborn. J Expo Sci Environ Epidemiol. 2008;18(3):326–31.
81.Ask-Björnberg K, Vahter M, Petersson-Grawé K, Glynn A, Cnattingius S, Darnerud PO, et al. Methyl mercury and inorganic mercury in Swedish pregnant women and in cord blood: influence of fish consumption. Environ Health Perspect. 2003; 111(4): 637–41.
82.Lindow SW, Knight R, Batty J, Haswell SJ. Maternal and neonatal hair mercury concentrations: the effect of dental amalgam. Journal of Obstetrics and Gynecology. 2003; 23(S1):S48-S49.
83.Lutz E, Lind B, Herin P, Krakau I, Bui TH, Vahter M. Concentrations of mercury, cadmium and lead in brain and kidney of second trimester fetuses and infants. J Trace Elem Med Biol. 1996; 10(2):61–7.
84.da Costa SL, Malm O, Dorea JG. Breast-milk mercury concentrations and amalgam surface in mothers from Brazilia, Brazil. Biol Trace Elem Res. 2005; 106(2): 145–51.
85.Geier DA, Kern JK, Geier MR. A prospective study of prenatal mercury exposure from dental amalgams and autism severity. Neurobiolgiae Experimentals Polish Neuroscience Society. 2009; 69(2): 189-197.
86.Ask K, Akesson A, Berglund M, Vahter M. Inorganic mercury and methylmercury in placentas of Swedish women. Environ Health Perspect 2002; 110(5):523-6.
87.Vahter M, Akesson A, Lind B, Bjors U, Schutz A, Berglund M. Longitudinal study of methylmercury and inorganic mercury in blood and urine of pregnant and lactating women, as well as in umbilical cord blood. Environ Res. 2000; 84(2):186-94.
88.Mutter J. Is dental amalgam safe for humans? The opinion of the scientific committee of the European Commission. Journal of Occupational Medicine and Toxicology. 2011; 6:2.
89.Norouzi E, Bahramifar N, Ghasempouri SM. Effect of teeth amalgam on mercury levels in the colostrums human milk in Lenjan. Environ Monit Access. 2012; 184(1):375-380.
90.Vimy MJ, Hooper DE, King WW, Lorscheider FL. Mercury from maternal “silver” tooth fillings in sheep and human breast milk. Biological Trace Element Research. 1997; 56(2): 143-152.
91.Richardson GM, Wilson R, Allard D, Purtill C, Douma S, Gravière J. Mercury exposure and risks from dental amalgam in the US population, post-2000. Science of the Total Environment. 2011; 409(20): 4257-4268.
92.Vimy MJ, Takahashi Y, Lorscheider FL. Maternal-fetal distribution of mercury (203 Hg) released from dental amalgam fillings. American Physiology Society. 1990; 258(4): R939-945.
93.Oskarsson A, Schutz A, Schkerving S, Hallen IP, Ohlin B, Lagerkvist BJ. Total and inorganic mercury in breast milk in relation to fish consumption and amalgam in lactating women. Arch Environ Health. 1996; 51(3):234-51.
94.Geier DA, Kern JK, Geier MR. The biological basis of autism spectrum disorders: Understanding causation and treatment by clinical geneticists. Acta Neurobiol Exp (Wars). 2010; 70(2): 209-226.
95.Mutter J, Naumann J, Schneider R, Walach H, Haley B. Mercury and autism: accelerating evidence. Neuro Endocrinol Lett. 2005: 26(5): 439-446.
96.Ask-Björnberg K, Vahter M, Petersson-Grawé K, Glynn A, Cnattingius S, Darnerud PO, et al. Methyl mercury and inorganic mercury in Swedish pregnant women and in cord blood: influence of fish consumption. Environ Health Perspect. 2003;111(4): 637–41.
97.da Costa SL, Malm O, Dorea JG. Breast-milk mercury concentrations and amalgam surface in mothers from Brazilia, Brazil. Biol Trace Elem Res. 2005; 106(2): 145–51.
98.Oskarsson A, Schutz A, Schkerving S, Hallen IP, Ohlin B, Lagerkvist BJ. Total and inorganic mercury in breast milk in relation to fish consumption and amalgam in lactating women. Arch Environ Health. 1996; 51(3):234-51.
99.Norouzi E, Bahramifar N, Ghasempouri SM. Effect of teeth amalgam on mercury levels in the colostrums human milk in Lenjan. Environ Monit Access. 2012; 184(1): 375-380.
100.Geier DA, Carmody T, Kern JK, King PG, Geier MR. A significant dose-dependent relationship between mercury exposure from dental amalgams and kidney integrity biomarkers A further assessment of the Casa Pia children’s dental amalgam trial. Human & Experimental Toxicology. 2013; 32(4):434-440.
101.Guzzi, G; Pigatto, PD. Urinary mercury levels in children with amalgam fillings. Environ Health Perspect. 2008; 116(7):A286-7.
102.Geier DA, Carmody T, Kern JK, King PG, Geier MR. A significant relationship between mercury exposure from dental amalgams and urinary porphyrins: a further assessment of the Casa Pia children’s dental amalgam trial. Biometals. 2011; 24, (2):215-224.
103.Al-Saleh I, Al-Sedairi A. Mercury (Hg) burden in children: The impact of dental amalgam. Sci Total Environ. 2011; 409(16):3003-3015.
104.Ask K, Akesson A, Berglund M, Vahter M. Inorganic mercury and methylmercury in placentas of Swedish women. Environ Health Perspect. 2002; 110(5):523-6.
105.Vahter M, Akesson A, Lind B, Bjors U, Schutz A, Berglund M. Longitudinal study of methylmercury and inorganic mercury in blood and urine of pregnant and lactating women, as well as in umbilical cord blood. Environ Res. 2000; 84(2):186-94.
106.Holmes, AS, Blaxill, MF, Haley, BE. Reduced levels of mercury in first baby haircuts of autistic children. Int J Toxicol. 2003. 22 (4): 277-85.
107.Haley BE. Mercury toxicity: genetic susceptibility and synergistic effects. Medical Vertias. 2005; 2(2): 535-542.
108.Woods JS, Heyer NJ, Echeverria D, Russo JE, Martin MD, Bernardo MF, Luis HS, Vaz L, Farin FM. Modification of neurobehavioral effects of mercury by a genetic polymorphism of coproporphyrinogen oxidase in children. Neurotoxicol Teratol. 2012; 34(5):513-21.
109.Dunn JE, Trachtenberg FL, Barregard L, Bellinger D, McKinlay S. Scalp hair and urine mercury content of children in the northeast United States: the New England children’s amalgam trial. Environ Res. 2008; 107(1):79–88.
110.Djerassi E, Berova N. The possibilities of allergic reactions from silver amalgam restorations. Internat Dent J, 1969, 19(4):481-8, 1969.
111.Finne K, Goransson K, Winckler L. Oral lichen planus and contact allergy to mercury. Int J Oral Surg. 1982; 11(4):236-9.
112.Miller, EG, Perry WL, Wagner MJ. Prevalence of mercury hypersensitivity in dental students. J Dent Res. 1985; 64: Special Issue, p. 338, Abstract #1472.
113.Sterzl I, Procházková J, Hrdá P, Bártová J, Matucha P, Stejskal VD. Mercury and nickel allergy: risk factors in fatigue and autoimmunity. Neuro Endocrinol Lett. 1999; 20: 221-228.
114.Prochazkova J, Sterzl I, Kucerova H, Bartova J, Stejskal VD. The beneficial effect of amalgam replacement on health in patients with autoimmunity. Neuro Endocrinol Lett. 2004; 25(3): 211-218.
115.Tomka M, Machovkova A, Pelclova D, Petanova J, Arenbergerova M, Prochazkova J. Orofacial granulomatosis associated with hypersensitivity to dental amalgam. Science Direct. 2011; 112(3):335-341.
116.Lundstrom, IM. Allergy and corrosion of dental materials in patients with oral lichen planus. Int J Oral Surg. 1984; 13(1):16.
117.Laine, J, Kalimo K, Forssell H, Happonen R. Resolution of oral lichenoid lesions after replacement of
amalgam restorations in patients allergic to mercury compounds. JAMA. 3 June 1992; 267(21):2880.
118.Lind PO, Hurlen B, Lyberg T, Aas E. Amalgam-related oral lichenoid reaction. Scand J Dent Res. 1986; 94(5):448-51.
119.Pang BK, Freeman S. Oral lichenoid lesions caused by allergy to mercury in amalgam fillings. Contact Dermatitis. 1995; 33(6):423-7.
120.Athavale PN, Shum KW, Yeoman CM, Gawkrodger DJ. Oral lichenoid lesions and contact allergy to dental mercury and gold. Contact Dermatitis. 2003; 49(5): 264-265.
121.Hougeir FG, Yiannias JA, Hinni ML, Hentz JG, el-Azhary RA. Oral metal contact allergy: a pilot study on the cause of oral squamous cell carcinoma. Int J Dermatol. 2006; 45(3): 265-271.
122.Kaaber S. Allergy to dental materials with special reference to the use of amalgam and polymethylmethacrylate. Int Dent J. 1990; 40(6): 359.
123.Lee JY, Yoo JM, Cho BK, Kim HO. Contact dermatitis in Korean dental technicians. Contact Dermatitis. 2001; 45(1), 13-16.
124.Venclikova Z, Benada O, Bartova J, Joska L, Mrklas L, Prochazkova J, Stejskal V, Podzimek S. In vivo effects of dental casting alloys. Neuro Endocrinol Lett. 2006; 27: 61.
125.Weber ME, Yiannias JA, Hougeir FG, Kyle A, Noble BN, Landry AM, Hinni ML. Intraoral metal contact allergy as a possible risk factor for oral squamous cell carcinoma. Ann Otol Rhinol Laryngol. 2012; 121(6):389-94.
126.White RR, Brandt RL. Development of mercury hypersensitivity among dental students. JADA. 1976; 92(6):1204-7.
127.Finne KAJ, Göransson K, Winckler L. Oral lichen planus and contact allergy to mercury. International Journal of Oral Surgery. 1982; 11(4):236-239.
128.Mutter J. Is dental amalgam safe for humans? The opinion of the scientific committee of the European Commission. Journal of Occupational Medicine and Toxicology. 2011; 6:2.
129.Bartova J, Prochazkova J, Kratka Z, Benetkova K, Venclikova C, Sterzl I. Dental amalgam as one of the risk factors in autoimmune disease. Neuro Endocrinol Lett. 2003; 24(1-2): 65-67.
130.Hultman P, Johansson U, Turley SJ, Lindh U, Enestrom S, Pollard KM. Adverse immunological effects and autoimmunity induced by dental amalgam and alloy in mice. FASEB J. 1994; 8(14):1183-90.
131.Weiner JA, Nylander M, Berglund F. Does mercury from amalgam restorations constitute a health hazard? Sci Total Environ. 1990; 99(1-2):1-22.
132.Eggleston DW. Effect of dental amalgam and nickel alloys on T-lymphocytes: preliminary report. J Prosthet Dent. 1984; 51(5):617-23.
133.Prochazkova J, Sterzl I, Kucerkova H, Bartova J, Stejskal VDM. The beneficial effect of amalgam replacement on health in patients with autoimmunity. Neuroendocrinology Letters. 2004; 25(3): 211-218.
134.Cooper GS, Parks CG, Treadwell EL, St Clair EW, Gilkeson GS, Dooley MA. Occupational risk factors for the development of systemic lupus erythematosus. J Rheumatol. 2004; 31(10): 1928-1933.
135.Barregard L, Fabricius-Lagging E, Lundh T, Molne J, Wallin M, Olausson M, Modigh C, Sallsten G. Cadmium, mercury, and lead in kidney cortex of living kidney donors: impact of different exposure sources. Environ, Res. Sweden, 2009; 110: 47-54.
136.Nylander M., Friberg L, Lind B. Mercury concentrations in the human brain and kidneys in relation to exposure from dental amalgam fillings. Swed Dent J. 1987; 11(5): 179-187.
137.Mortada WL, Sobh MA, El-Defrawi, MM, Farahat SE. Mercury in dental restoration: is there a risk of nephrotoxity? J Nephrol. 2002; 15(2): 171-176.
138.Fredin B. The distribution of mercury in various tissues of guinea-pigs after application of dental amalgam fillings (a pilot study). Sci Total Environ. 1987; 66: 263-268.
139.Boyd ND, Benediktsson H, Vimy MJ, Hooper DE, Lorscheider FL. Mercury from dental “silver” tooth fillings impairs sheep kidney function. Am J Physiol. October 1991;261(4 Pt 2):R1010-4.
140.Mutter J. Is dental amalgam safe for humans? The opinion of the scientific committee of the European Commission. Journal of Occupational Medicine and Toxicology. 2011; 6:2.
141.Siblerud RL. A comparison of mental health of multiple sclerosis patients with silver/mercury dental fillings and those with fillings removed. Psychol Rep. 1992; 70(3c):1139-51.
142.Huggins HA, Levy TE. Cerebrospinal fluid protein changes in multiple sclerosis after dental amalgam removal. Altern Med Rev. 1998; 3(4): 295-300.
143.Siblerud RL, Kienholz E. Evidence that mercury from silver dental fillings may be an etiological factor in multiple sclerosis. The Science of the Total Environment. 1994; 142(3): 191-205.
144.Laine J, Kalimo K, Forssell H, Happonen R. Resolution of Oral Lichenoid Lesions After Replacement of
Amalgam Restorations in Patients Allergic to Mercury Compounds. JAMA. 1992; 267(21):2880.
145.Lind PO, Hurlen B, Lyberg T, Aas E. Amalgam-related oral lichenoid reaction. Scand J Dent Res. 1986 Oct;94(5):448-51.
146.Henriksson E, Mattsson U, Håkansson J. Healing of lichenoid reactions following removal of amalgam. A clinical follow-up. J Clin Periodontol. 1995; 22(4):287-94.
147.Ibbotson SH, Speight EL, Macleod RI, Smart ER, Lawrence CM. The relevance and effect of amalgam replacement in subjects with oral lichenoid reactions. British Journal of Dermatology. 1996; 134(3):420-423.
148.Camisa C, Taylor JS, Bernat JR, Helm TN. Contact hypersensitivity to mercury in amalgam restorations may mimic oral lichen planus. Cutis. 1999; 63(3):189-92.
149.Dunsche A, Kastel I, Terheyden H, Springer ING, Christopher E, Brasch J. Oral lichenoid reactions associated with amalgam: improvement after amalgam removal. British Journal of Dermatology. 2003; 148(1):70-76.
150.Wong L, Freeman S. Oral lichenoid lesions (OLL) and mercury in amalgam fillings. Contact Dermatitis. 2003; 48(2): 74-79.
151.Finne K, Goransson K, Winckler L. Oral Lichen Planus and Contact Allergy to Mercury. Int J Oral Surg. 1982; 11(4):236-9.
152.Lundstrom, IM. Allergy and Corrosion of Dental Materials in Patients With Oral Lichen Planus. Int J Oral Surg. 1984; 13(1):16.
153.Athavale PN, Shum KW, Yeoman CM, Gawkrodger DJ. Oral lichenoid lesions and contact allergy to dental mercury and gold. Contact Dermatitis. 2003; 49(5): 264-265.


 

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TAINTED WATER, TAINTED TEETH:
THE DANGERS OF FLUORIDE

By David Kennedy, DDS, MIAOMT, and Amanda Just

Jeff Green photo

December’s edition of DPNL about fluoride is dedicated to Jeffrey Lee Green,
an IAOMT member and friend who spent over 15 years working to end the use
of fluoride in the water supply.

His website is at http://www.keepers-of-the-well.org/
He passed away in November 2014.

 

In the spring of 2013, community members in Portland, Oregon, celebrated their victory of preventing water fluoridation in their city after 60% of voters opted against it.1 In many ways, those rejecting the $7.6 million plan2 represented a series of citizens who have fought the use of fluoride for over half a century. When fluoride was first introduced to the water supply in the 1950’s as a public health program to reduce dental cavities, those who questioned it were ridiculed, but today, groups arguing against the use of fluoride have scientific evidence and government documents to support their concerns.

Perhaps the most important proof of dangers associated with fluoride is the National Research Council’s 2006 report about the issue, which identified potential health risks from the compound and recommended setting a lower acceptable dosage of fluoride for the United States.3

Fluoride is currently added to the water of approximately 60% of the American population.4 It is also found in dental products such as toothpaste and floss, food and beverages, pesticides, and other products, including pharmaceutical drugs such as Prozac and Cipro. The total of fluoride exposure to the average U.S. resident is important to consider when evaluating safe levels of water fluoridation. This is because there is no clear estimate of the amount of fluoride taken in from sources other than the water supply,5 which makes it difficult to estimate how much fluoride is actually ingested overall.

That being said, the United States Environmental Protection Agency (EPA) set a maximum contaminant level (MCL) [a “safe level”] of 4 milligrams per liter (mg/L) for fluoride in drinking water.6 Yet, according to the National Research Council (NRC) report, “Estimates from 1992 indicate that approximately 1.4 million people in the United States had drinking water with natural fluoride concentrations of 2.0 to 3.9 mg/L, and just over 200,000 people had concentrations equal to or exceeding 4 mg/L (the presented MCL). In 2000, it was estimated that approximately 162 million people had artificially fluoridated water (0.7 to 1.2 mg/L).”7

Another issue with the established “safe levels” for fluoride is applying the same safe dosage level to children as well as adults. Since children are smaller and still developing, some have argued that separate safe levels should be enacted for them. To add to this concern, warnings have been made that many American babies are bottle-fed milk or soy formula after birth, which is powder reconstituted with water. Since bottled water is expensive and can also contain unlabeled fluoride, many of these babies end up drinking formula mixed with municipal tap water that contains fluoride as their main nutritional source for the first several months of their lives.

Indeed, the hazards of using fluoride on children have been documented. Exposure to excess fluoride in children is known to result in dental fluorosis, a condition in which the teeth become discolored, displaying a white or brown mottling pattern and forming brittle teeth that break and stain easily.8 According to the Centers for Disease Control, 23% of Americans aged 6-49 and 41% of children aged 12-15 exhibit fluorosis to some degree.9

The implication of fluoride in the instigation of childhood cancer is even more alarming. Data has pointed toward a link between fluoride exposure and osteosarcoma, a bone cancer, in boys and young men. This type of cancer is recognized as “the sixth most common group of malignant tumors in children and the third most common malignant tumor for adolescents.”10

According to research completed by Dr. Elise Bassin while at Harvard School of Dental Medicine, exposure to fluoride at the currently recommended level correlated with a seven-fold increase in osteosarcoma when boys were exposed between the ages of five and seven.11 Disturbingly, these results were incorrectly reported by her graduate advisor, Dr. Chester Douglas, in his report to the agency funding the work. However, allegations of conflicts of interest were raised because Dr. Douglas serves as editor of the dental manufacturer Colgate’s newsletter, and Colgate supports fluoride use.

In addition to recognizing the risk of fluoride and osteosarcoma, the 2006 National Research Council report cited concerns about musculoskeletal effects, reproductive and developmental effects, neurotoxicity and neurobehavioral effects, genotoxicity and carcinogenicity, and effects on other organ systems.12

While the NRC was cautious about noting some of these potential health risks related to fluoride, the danger of bone fractures from excessive fluoride was substantiated with significant research. Specifically, the report states, “Overall, there was consensus among the committee that there is scientific evidence that under certain conditions fluoride can weaken bone and increase the risk of fractures. The majority of the committee concluded that lifetime exposure to fluoride at drinking-water concentrations of 4 mg/L or higher is likely to increase fracture rates in the population, compared with exposure to 1 mg/L, particularly in some demographic subgroups that are prone to accumulate fluoride into their bones (e.g., people with renal disease).”13

Furthermore, fluoride, in its form of hydrofluosilicic acid (which is added to many water supplies to fluoridate the water), attracts lead. Likely because of this affinity for lead, fluoride has been linked to higher blood lead levels in children,14 especially in minority groups.15 Lead is known to lower IQs in children,16 and lead has even been linked to violent behavior.17,18

Research from Masters (2003) entitled “The social implications of evolutionary psychology: Linking brain biochemistry, toxins, and violent crime” ominously warns about the potential impact of fluoride on volatile behaviors:

As our analysis shows, it is now time to link neuroscience, evolutionary psychology, and toxicology to such social behavior as violence. Just as the ban on leaded gasoline seems to have lowered rates of violent crime since 1991, other initiatives may have substantial benefits by reducing the risks of dysfunctional behavior caused by toxins.

To illustrate a policy derived from this approach, I have proposed a moratorium on injecting fluosilicic acid or sodium silicofluoride in a public water supply until extensive testing proves their safety. Such testing is especially necessary for chemicals that are distributed to the general public in a manner not subject to individual choice.19

In the midst of current research, changes in safe dosage levels of fluoride are clearly merited. Ironically, even the claims of fluoride preventing cavities have been questioned, since some countries with no water fluoridation have less evidence of tooth decay than countries like the US.20 While many anticipate government action on the issue in the US, as it stands now, dental professionals have the responsibility to evaluate the latest evidence when considering whether or not to endorse the use of fluoride.


1. Associated Press. Portland, Ore., rejects adding fluoride to drinking water. USA Today. May 22, 2013. http://www.usatoday.com/story/news/nation/2013/05/22/portland-fluoride-water/2350329/
2. Clean Water Portland. 12 reasons to vote no. Clean Water Portland Website. http://www.cleanwaterportland.org/12_reasons_to_vote_no
3. National Research Council. Fluoride in Drinking Water: A Scientific Review of EPA’s Standards. The National Academies Press: Washington, D.C. 2006.
4. Fagin D. Second thoughts about fluoride: New research indicates a cavity fighting treatment could be risky if overused. Scientific American. January 2008: 74-81.
5. Fagin D. Second thoughts about fluoride: New research indicates a cavity fighting treatment could be risky if overused. Scientific American. January 2008: 74-81.
6. United States Environmental Protection Agency. Basic Information about fluoride in drinking water. EPA Website. http://water.epa.gov/drink/contaminants/basicinformation/fluoride.cfm
7. National Research Council. Fluoride in Drinking Water: A Scientific Review of EPA’s Standards. The National Academies Press: Washington, D.C. 2006.
8. National Research Council. Fluoride in Drinking Water: A Scientific Review of EPA’s Standards. The National Academies Press: Washington, D.C. 2006.
9. Centers for Disease Control and Prevention. Prevalence and severity of dental fluorosis in the United States, 1999-2004. NCHS Data Brief. November 2010, Number 53. http://www.cdc.gov/nchs/data/databriefs/db53.htm
10. Bassin EB, Wypij D, Davis RB, Mittleman MA. Age-specific fluoride exposure in drinking water and osteosarcoma. Cancer Causes & Control. 2006; 17(4): 421-428.
11. Bassin EB, Wypij D, Davis RB, Mittleman MA. Age-specific fluoride exposure in drinking water and osteosarcoma. Cancer Causes & Control. 2006; 17(4): 421-428.
12. National Research Council. Fluoride in Drinking Water: A Scientific Review of EPA’s Standards. The National Academies Press: Washington, D.C. 2006.
13. National Research Council. Fluoride in Drinking Water: A Scientific Review of EPA’s Standards. The National Academies Press: Washington, D.C. 2006.
14. Masters R. and Coplan M. Silicofluorides — are associated with an increase in children’s absorption of lead. International Journal of Environmental Studies. 1999; 56:435.
15. Masters RD, Coplan MJ, Hone BT, Dykes JE. Association of Silicofluoride Treated Water with Elevated Blood Lead. Neurotoxicology. 2000; 21(6):1091-1100.
16. Needleman HL, Gatsonis CA. Low-level lead exposure and the IQ of children. JAMA. 1990; 263(5): 673-678.
17. Vedantam S. Research links lead exposure, criminal activity. The Washington Post. July 8, 2007. http://www.washingtonpost.com/wp-dyn/content/article/2007/07/07/AR2007070701073.html
18. Goodwin H. Lead exposure and poisoning in children. Southern California Environmental Report Card. UCLA Institute of the Environment and Sustainability. Spring 2009. http://www.environment.ucla.edu/reportcard/article.asp?parentid=3772
19. Masters RD. The social implications of evolutionary psychology: Linking brain biochemistry, toxins, and violent crime. Chapter in Evolutionary Psychology and Violence: A Primer for Policymakers and Public Policy Advocates. Westwood: Praeger; 2003: 23-56.
20. Fagin D. Second thoughts about fluoride: New research indicates a cavity fighting treatment could be risky if overused. Scientific American. January 2008: 74-81.


 

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LESSONS FROM LEAD PAINT, LEADED GAS, AND MERCURY FILLINGS:
COMPARING HISTORY, INDUSTRIAL REGULATIONS, AND SCIENCE

By David Kennedy, DDS, MIAOMT, and Amanda Just

While lead and mercury certainly have their own distinct characteristics, striking similarities between the two heavy metals exist. A comparison of the two elements provides an interesting pattern of how toxic products have previously been managed, are being managed now, and possibly will be managed in the future. From their past histories to their current regulations and growing scientific evidence about their toxicity, lead and mercury have many commonalities that offer important lessons for a society gradually becoming aware of how poisonous practices can seriously impair human health.

Past Practices

Both lead and mercury were recognized as far back as ancient times for being toxic.1,2 Roman philosopher Pliny the Elder described lead as being “decidedly risky” for medicine,3 and also in the 1st century AD, a Greek doctor by the name of Dioscorides acknowledged mercury to be harmful if ingested.4

While lead was used for everyday products and even plumbing pipes in the Roman Empire,5 mercury was used for making hats and a variety of medical purposes, eventually including the treatment of syphilis.6 Yet, both heavy metals were associated with causing major psychological issues to tradesmen who used them. For example, the lead used in paint has been implicated in the coining of the phrase “crazy as a painter,”7 and the mercury used in hat-making has been implicated in the coining of the phrase “mad as a hatter.”8

Unfortunately, the continued use of lead and mercury in spite of their known dangers resulted in notable 20th century tragedies in both circumstances. Lead poisoning killed 15 people who were working at refineries with tetraethyl lead in 1924,9 and by the 1930’s it had caused serious health issues in many children, ranging from seizures to coma to death.10 Likewise, industrial mercury released into Japan’s Minamata Bay in 1958 caused thousands of deaths, and wheat contaminated with mercury resulted in a health epidemic in Iraq from 1971-2.11

Regulations and Industry

In spite of their “bad reputations” from the past, both heavy metals continue to be used today, largely driven by industrial purposes. Lead has been used in paint and gasoline, although regulations, first existent in the United States during the 1970’s, now limit such use. Meanwhile, mercury is used in a number of products and practices, including coal-fired power plants, gold mining, and dental amalgam mercury. Wide-scale regulation of mercury has only very recently been considered and in some cases enacted.

Part of the delay in modern regulations has notoriously been linked to industrial interests. In the case of lead, the paint industry fought attempted measures with marketing and lobbying.12 Industrial powers openly questioned solid scientific evidence establishing health risks from lead and threatened to sue popular TV shows such as Highway Patrol for suggesting that lead13 was harmful.14

It can be said that dental mercury has suffered a somewhat similar fate. Despite hundreds of peer-reviewed studies demonstrating health risks of amalgam fillings,15 which contain 50% mercury, the United States Food and Drug Administration (FDA) and American Dental Association (ADA) continue to endorse dental amalgam mercury as safe.16,17 The ADA has also employed marketing efforts and press campaigns to vehemently defend mercury fillings after shows such as 60 Minutes18 and Dr. Oz19 aired episodes about health problems potentially related to mercury fillings.

In both cases, industry has certainly benefited from the use of these toxic heavy metals. A subsidiary of General Motors was reported to have considered tetraethyl lead a “virtual savior of the American automobile industry.”20 The ADA could say the same thing about mercury tooth restorations because the widespread acceptance of amalgam instead of the more expensive gold (or less enticing tooth extraction) allowed the dental industry to vastly expand.21

“Manufacturing doubt” about an industrial product’s danger is a tactic widely known to be used to justify its continued use in spite of hazard. Stanton Glantz, a professor of medicine and tobacco control at the University of California, San Francisco, explained, “Whether you’re talking about tobacco or global warming denial or toxics in furniture, it’s all the same strategies…It’s this whole idea of creating doubt. Then it becomes a ‘he said, she said,’ and the weight of evidence gets lost.”22

However, regulations have somewhat superseded industrial interests for both lead and mercury, although more so for lead. While nearly a dozen European countries were decades ahead of the US in lead paint regulations,23 the US Congress did finally ban the residential use of lead paint in 1978.24 Just two years prior to that, the US Environmental Protection Agency (EPA) had developed a plan for a “gradual phase-down” of the amount of lead in gas.25

This same pattern appears to be repeating itself for dental mercury. For one, Europe is again leading the way, with Norway, Sweden, and Denmark banning the use of dental amalgam mercury26 and several other countries restricting its use for sensitive populations.27 Additionally, while the ADA and other groups requested for dental amalgam not to be banned or limited in a United Nations Programme’s mercury treaty,28 it was included in Annex A of the 2013 Minamata Convention on Mercury.29 Over 90 countries have signed the agreement, which calls for the “gradual phase-down” on mercury-containing fillings, thus using terminology similar to what the EPA had used for lead-containing gas.

Conflict, Controversy, and Criticism

One of the issues that occurred in the debate over regulations in both cases involves agreeing upon an acceptable level of human exposure to the toxic chemicals. Proponents of mercury and lead usage have used the excuse that low-level exposures are not dangerous.30,31 Interestingly enough, “acceptable” levels of lead were repeatedly changed over the years, becoming more and more cautious.32,33 Arguments over mercury levels are currently ongoing.34,35,36

Another recurring theme is the conflicting views of trade groups and other authorities with new scientific evidence. For example, in the case of lead, Dr. Herbert Needleman, a renowned expert on childhood lead poisoning, reportedly said, “Many in the American Academy of Pediatrics do not think lead poisoning is a problem.”37 The same can be said of the American Dental Association’s position on dental amalgam fillings, and not ironically, the same Dr. Herbert Needleman also commented on this issue. In an editorial about the highly controversial Children’s Amalgam Trials, which have been used to suggest dental mercury is safe for children, Dr. Needleman warned, “It is predictable that some outside interests will expand the modest conclusions of these studies to assert that use of mercury amalgam in dentistry is risk free. That conclusion would be unfortunate and unscientific.”38

Indeed, both lead and mercury have since been well-recognized for their harm to children, as well as adults. In fact, the National Safety Council says of children and lead poisoning:

Young children under the age of six are especially vulnerable to lead’s harmful health effects, because their brains and central nervous system are still being formed. For them, even very low levels of exposure can result in reduced IQ, learning disabilities, attention deficit disorders, behavioral problems, stunted growth, impaired hearing, and kidney damage. At high levels of exposure, a child may become mentally retarded, fall into a coma, and even die from lead poisoning.39

The National Safety Council’s warning for adults is as follows: “In adults, lead can increase blood pressure and cause fertility problems, nerve disorders, muscle and joint pain, irritability, and memory or concentration problems.”40 Both of the National Safety Council’s descriptions definitely bear resemblance to the World Health Organization’s list of health risks for mercury:

It may cause harmful effects to the nervous, digestive, respiratory, immune systems and to the kidneys, besides causing lung damage. Adverse health effects from mercury exposure can be: tremors, impaired vision and hearing, paralysis, insomnia, emotional instability, developmental deficits during fetal development, and attention deficit and developmental delays during childhood. Recent studies suggest that mercury may have no threshold below which some adverse effects do not occur.41

Furthermore, both lead and mercury poisoning have been tied to the factor of socioeconomic class. Many have agreed that lead is more commonly found in the homes of children in areas of lower socioeconomic status.42 An article from UCLA’s Institute of the Environment and Sustainability notes, “Children who are Medicaid-eligible are categorized as a ‘vulnerable population’ because they are more likely to live in lead-contaminated housing and are much more likely to have an elevated blood lead level than the average non-eligible child living in the same state or region.”43

Again, this same concept can be applied to dental amalgam. This is because some insurance companies only cover the cost of dental mercury amalgam fillings which means that oftentimes consumers have to pay additional fees for alternative materials and techniques.44 An article in a law school journal elaborates on this problem when the author notes, “Additionally, because Medicaid does not cover alternative fillings, many low-income Americans are forced to choose between mercury fillings or no fillings at all.”45

Furthermore, whereas amalgams are now only being used for 45% of direct dental restorations,46 according the Journal of the American Dental Association, these fillings are still being used routinely on 53.4% of Black/African Americans, on 72.9% of American Indians/Alaska Natives/Asians/Pacific Islanders,47 and on more than 75% of posterior restorations for new recruits to the U.S. Navy and Marines.48

Yet another troubling aspect of both mercury and lead is that in both cases, patients have been blamed for their health conditions. This “blame the victim” mentality is well-documented for lead,49,50,51 probably since time has elapsed since the initial harassment. A 2013 article in The Atlantic described this issue:

The lead industry even sought to place the blame for lead poisoning epidemic on parents and children, claiming that the problem was not with the lead paint but with the ‘uneducable Negro and Puerto Rican’ parents who ‘failed’ to stop children from placing their fingers and toys in their mouths. Children poisoned by lead, the industry claimed, had a disease that led them to suck on ‘unnatural objects’ and thereby get poisoned.52

Patients claiming to be negatively impacted by their dental amalgam fillings have also been ostracized. Some researchers have even gone so far as to publish scientific articles suggesting the patients who report ill health from their dental fillings have psychological issues or “tendencies to somatization.”53,54

Brief Introduction to the Science of Lead and Mercury Toxicity

Scientific studies documenting risks of lead and mercury have been questioned by authorities throughout the years. Yet, as more people accepted that lead is a threat to human health, more studies validated it. To illustrate this point, a 2008 news report identified that 6000 studies since 1990 established hazardous health consequences of lead exposure.55 In contrast, a simple literature search conducted on dental mercury risk in 2013 by the International Academy of Oral Medicine and Toxicology using their own library and PUBMED resulted in nearly 200 studies showing potential health risks of dental amalgam.56 It will be interesting to conduct this literature search again several decades from now since the volume of scientific evidence about mercury is increasing in the same way lead research evolved.

Some areas of research that merit mention are that both heavy metals have been linked to lower intelligence quotients57,58 and autism,59,60,61,52,63 and genetic factors have been cited as having a potential role in patient response to lead and mercury exposures.64 The two toxic chemicals are also known to have a synergistic effect65,66 and for their ability to produce different symptoms in different patients.67.68

Finally, lead and mercury have both been suspected as possible triggers for neurobehavioral consequences, ranging from mood changes to violence. Lead has been the subject of attention for a variety of reports relating criminal behavior to body levels of the heavy metal,69,70 including one by Dr. Herbert Needleman who reported, “The arrested youths had lead levels that were four times higher.”71 Neurobehavioral issues potentially related to mercury exposure have also been documented,72,73,74,75 and one study specifically offered evidence that dental amalgam mercury could be linked to “depression, excessive anger, and anxiety.”76

Applying the Past to the Future

While lead levels are known to have dropped due to regulatory action, today’s levels are still considered 100 times higher than those of the distant past.77 According to a 2013 article in The Huffington Post, lead poisoning expert Howard Mielke of Tulane University School of Medicine has said, “We still have a lead problem. It’s handicapping the future generation.”78

Yet, this is not the first time that the toxic chemical has been blamed for such destruction. In fact, a number of historians believe the lead plumbing pipes in Rome were part of the reason the once powerful empire fell.79 At least some have wondered if this same phenomena could be happening in today’s world, especially because of the prevalent existence of lead and mercury in everyday life and their known synergistic effect in increasing toxic responses.

While history, regulations, and science continue to shed light on humans’ understanding of lead and mercury poisoning, it is the health of the current population and the next generation that will inevitably serve as the controversial legacy of a society built on industry’s need for these toxic heavy metals.


1.Bellinger DC, Bellinger AM. Childhood lead poisoning: the torturous path from science to policy. Journal of Clinical Investigation. 2006; 116(4): 853-857.
2.Sloane J. Mercury: Element of the Ancients. Dartmouth Toxic Metals Superfund Research Program. http://www.dartmouth.edu/~toxmetal/mercury/history.html
3.Shell E. An element of doubt. The Atlantic. December 1995. The Atlantic Online. http://www.theatlantic.com/past/issues/95dec/lead/lead.htm
4.Hyson Jr, JM. Amalgam: its history and perils. CDA. JOURNAL. 2006; 34(3):215-229.
5.Lewis J. Lead poisoning: a historical perspective. EPA Journal. May 1985. United States Environmental Protection Agency Website. http://www2.epa.gov/aboutepa/lead-poisoning-historical-perspective
6.Sloane J. Mercury: Element of the Ancients. Dartmouth Toxic Metals Superfund Research Program. http://www.dartmouth.edu/~toxmetal/mercury/history.html
7.Lewis J. Lead poisoning: a historical perspective. EPA Journal. May 1985. United States Environmental Protection Agency Website. http://www2.epa.gov/aboutepa/lead-poisoning-historical-perspective
8.Hyson Jr, JM. Amalgam: its history and perils. CDA. JOURNAL. 2006; 34(3):215-229.
9.Lewis J. Lead poisoning: a historical perspective. EPA Journal. May 1985. United States Environmental Protection Agency Website. http://www2.epa.gov/aboutepa/lead-poisoning-historical-perspective
10.Shell E. An element of doubt. The Atlantic. December 1995. The Atlantic Online. http://www.theatlantic.com/past/issues/95dec/lead/lead.htm
11.Sloane J. Mercury: Element of the Ancients. Dartmouth Toxic Metals Superfund Research Program. http://www.dartmouth.edu/~toxmetal/mercury/history.html
12.Rosner D, Markowitz G. Why it took decades of blaming parents before we banned lead paint. The Atlantic. April 22, 2013. http://www.theatlantic.com/health/archive/2013/04/why-it-took-decades-of-blaming-parents-before-we-banned-lead-paint/275169/
13.Fowler T. A brief history of lead regulation. Science Progress. October 21, 2008. http://scienceprogress.org/2008/10/a-brief-history-of-lead-regulation/
14.Rosner D, Markowitz G. Why it took decades of blaming parents before we banned lead paint. The Atlantic. April 22, 2013. http://www.theatlantic.com/health/archive/2013/04/why-it-took-decades-of-blaming-parents-before-we-banned-lead-paint/275169/
15.Kall JC, Robertson KM, Sukel PP, Just AR. International Academy of Oral Medicine and Toxicology position statement against dental mercury amalgam fillings for medical and dental practitioners, dental students, and patients. Champion’sGate, FL: IAOMT; Revised 2014.
16.United States Food and Drug Administration. Medical Devices: about dental amalgam fillings. http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/DentalProducts/DentalAmalgam/ucm171094.htm
17.American Dental Association. Dental Amalgam: Overview. http://www.ada.org/2468.aspx
18.Sehnert KW, Jacobson G, Sullivan K. Is mercury toxicity an autoimmune disorder? Townsend Letter for Doctors and Patients. (1999):100-103.
19.American Dental Association. American Dental Association Objects to the Dr. Oz show segment on dental amalgam [press release]. Chicago, Illinois American Dental Association. March 28, 2013. http://www.ada.org/8448.aspx
20.Lewis J. Lead poisoning: a historical perspective. EPA Journal. May 1985. United States Environmental Protection Agency Website. http://www2.epa.gov/aboutepa/lead-poisoning-historical-perspective
21.Ziff S, Ziff M. Dentistry without Mercury. IAOMT: ChampionsGate, FL. 2014.
22.Peeples L. Public Health Advocates Find Flame Retardant Fight Follows Familiar Formula. Huffington Post. February 7, 2014. http://www.huffingtonpost.com/2014/02/07/flame-retardants-tobacco-lead-paint_n_4734449.html?&ncid=tweetlnkushpmg00000048
23.Bellinger DC, Bellinger AM. Childhood lead poisoning: the torturous path from science to policy. Journal of Clinical Investigation. 2006; 116(4): 853-857.
24.Shell E. An element of doubt. The Atlantic. December 1995. The Atlantic Online. http://www.theatlantic.com/past/issues/95dec/lead/lead.htm
25.Bellinger DC, Bellinger AM. Childhood lead poisoning: the torturous path from science to policy. Journal of Clinical Investigation. 2006; 116(4): 853-857.
26.Reuters/PRNewswire-USNewswire Online. Dental mercury use banned in Norway, Sweden and Denmark because composites are adequate replacements [press release]. January 3, 2008. http://www.reuters.com/article/idUS108558+03-Jan-2008+PRN20080103
27.Health and Environment Alliance. Mercury and Dental Amalgams [fact sheet]. Brussels, Belgium: Health and Environment Alliance and Health Care without Harm; May 2007: 3. http://www.env-health.org/IMG/pdf/HEA_009-07.pdf
28.Academy of General Dentistry et al. Dear Dr. Thompson [letter to the US Department of State]. June 4, 2012. http://www.ada.org/sections/newsAndEvents/pdfs/US_Dept_of_State_letter_6_3_12.pdf
29.United Nations Environment Programme. Minamata Convention on Mercury. Geneva, Switzerland: Text agreed upon in UNEP(DTIE)/Hg/INC.5/3; January 13-19, 2013. http://www.mercuryconvention.org/Portals/11/documents/conventionText/Minamata%20Convention%20on%20Mercury_e.pdf
30.Shell E. An element of doubt. The Atlantic. December 1995. The Atlantic Online. http://www.theatlantic.com/past/issues/95dec/lead/lead.htm
31.National Institute of Dental Research. National Institute of Dental Research (NIDR) Workshop on the biocompatibility of metals in dentistry. JADA. 1984; 109: 169-171.
32.Bellinger DC, Bellinger AM. Childhood lead poisoning: the torturous path from science to policy. Journal of Clinical Investigation. 2006; 116(4): 853-857.
33.Goodwin H. Lead exposure and poisoning in children. Southern California Environmental Report Card. UCLA Institute of the Environment and Sustainability. Spring 2009. http://www.environment.ucla.edu/reportcard/article.asp?parentid=3772
34.Richardson GM, Wilson R, Allard D, Purtill C, Douma S, Gravière J. Mercury exposure and risks from dental amalgam in the US population, post-2000. Sci Total Environ. 2011; 409(20):4257-4268.
35.United States of America Department of Health and Human Services Food and Drug Administration, Center for Devices and Radiological Health Medical Devices Committee. Dental Products Panel [transcript]. December 14, 2010. http://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/MedicalDevices/MedicalDevicesAdvisoryCommittee/DentalProductsPanel/UCM242357.pdf
36.United States of America Department of Health and Human Services Food and Drug Administration, Center for Devices and Radiological Health Medical Devices Committee. Dental Products Panel [transcript]. December 15, 2010. http://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/MedicalDevices/MedicalDevicesAdvisoryCommittee/DentalProductsPanel/UCM242363.pdf
37.cited in Shell E. An element of doubt. The Atlantic. December 1995. The Atlantic Online. http://www.theatlantic.com/past/issues/95dec/lead/lead.htm
38.Needleman HL. Mercury in dental amalgam—a neurotoxic risk? JAMA. 2006; 295(15):1835-1836.
39.National Safety Council. Lead Poisoning. National Safety Council Website. http://www.nsc.org/news_resources/Resources/Documents/Lead_Poisoning.pdf
40.Ibid.
41.World Health Organization. Mercury in Health Care: Policy Paper. Geneva, Switzerland; August 2005. http://www.who.int/water_sanitation_health/medicalwaste/mercurypolpaper.pdf  Accessed February 17, 2013.
42.Shell E. An element of doubt. The Atlantic. December 1995. The Atlantic Online. http://www.theatlantic.com/past/issues/95dec/lead/lead.htm
43.Goodwin H. Lead exposure and poisoning in children. Southern California Environmental Report Card. UCLA Institute of the Environment and Sustainability. Spring 2009. http://www.environment.ucla.edu/reportcard/article.asp?parentid=3772
44.McCann D. “A Solution to our Country’s Big Health Care Problem? CFO. October 30, 2012. http://www3.cfo.com/article/2012/10/health-benefits_parker-hannifin-washkewicz-complementary-alternative-medicine-cam-sherri-tenpenny-chelation-mercury-fillings-pelletier Accessed February 26, 2013.
45.McGrath K. A Toxic Mouthful: the Misalignment of Dental Mercury Regulations. B.C.J.L. & Soc. Just. 2013; 33(2):347. http://lawdigitalcommons.bc.edu/jlsj/vol33/iss2/4
46.Heintze SD, Rousson V. Clinical effectiveness of direct Class II restorations—a meta-analysis. J Adhes Dent. 2012; 14(5):407-431.
47.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.
48.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): 200-209.
49.Bellinger DC, Bellinger AM. Childhood lead poisoning: the torturous path from science to policy. Journal of Clinical Investigation. 2006; 116(4): 853-857.
50.Rosner D, Markowitz G. Why it took decades of blaming parents before we banned lead paint. The Atlantic. April 22, 2013. http://www.theatlantic.com/health/archive/2013/04/why-it-took-decades-of-blaming-parents-before-we-banned-lead-paint/275169/
51.Peeples L. Lead poisoning and the middle class: the silent epidemic that doesn’t discriminate. Huffington Post. March 15, 2013. http://www.huffingtonpost.com/2013/03/15/lead-poisoning-children-middle-class_n_2880619.html
52.Rosner D, Markowitz G. Why it took decades of blaming parents before we banned lead paint. The Atlantic. April 22, 2013. http://www.theatlantic.com/health/archive/2013/04/why-it-took-decades-of-blaming-parents-before-we-banned-lead-paint/275169/
53.Langworth S, Bjorkman L, Elinder CG, Järup L, Savlin P. Multidisciplinary examination of patients with illness attributed to dental fillings. J Oral Rehabil. 2002; 29(8):705-13.
54.Bailer J, Rist F, Rudolf A, Staehle HJ, Eickholz P, Triebig G, Bader M, Pfeifer U. Adverse health effects related to mercury exposure from dental amalgam fillings: toxicological or psychological causes? Psychol Med. 2001; 31(2):255-63.
55.Fowler T. A brief history of lead regulation. Science Progress. October 21, 2008. http://scienceprogress.org/2008/10/a-brief-history-of-lead-regulation/
56.Kall JC, Robertson KM, Sukel PP, Just AR. International Academy of Oral Medicine and Toxicology position statement against dental mercury amalgam fillings for medical and dental practitioners, dental students, and patients. Champion’sGate, FL: IAOMT; Revised 2014.
57.Needleman HL, Gatsonis CA. Low-level lead exposure and the IQ of children. JAMA. 1990; 263(5): 673-678.
58.Trasande L, Landrigan P, and Schechter C. Public health and economic consequences of methyl mercury toxicity to the developing brain. Environmental Health Perspectives. 2005; 113(5).
59.Peeples L. Lead poisoning and the middle class: the silent epidemic that doesn’t discriminate. Huffington Post. March 15, 2013. http://www.huffingtonpost.com/2013/03/15/lead-poisoning-children-middle-class_n_2880619.html
60.Adams JB, Romdalvik J, Ramanujam VM, Legator MS. Mercury, lead, and zinc in baby teeth of children with autism versus controls, Part A. J Toxicol Environ Health. 2007; 70(12):1046-51.
61.Geier DA, Kern JK, Geier MR. A prospective study of prenatal mercury exposure from dental amalgams and autism severity. Neurobiolgiae Experimentals Polish Neuroscience Society. 2009; 69(2):189-197.
62.Mutter J, Naumann J, Schneider R, Walach H, Haley B. Mercury and autism: accelerating evidence. Neuro Endocrinol Lett. 2005: 26(5):439-446.
63.Haley BE. Mercury toxicity: genetic susceptibility and synergistic effects. Medical Vertias. 2005; 2(2):535-542.
64.Gundacker C, Wittmann KJ, Kukuckova M, Komarnicki G, Hikkel I, Gencik M. Genetic background of lead and mercury metabolism in a group of medical students in Austria. Environmental Research. 2009; 109(6): 786-796.
65.Haley BE. Mercury toxicity: genetic susceptibility and synergistic effects. Medical Veritas. 2005; 2(2): 535-42.
66.Schubert J, Riley EJ, Tyler SA. Combined effects in toxicology—a rapid systematic testing procedure: Cadmium, mercury, and lead. Journal of Toxicology and Environmental Health, Part A Current Issues. 1978; 4(5-6):763-776.
67.Goodwin H. Lead exposure and poisoning in children. Southern California Environmental Report Card. UCLA Institute of the Environment and Sustainability. Spring 2009. http://www.environment.ucla.edu/reportcard/article.asp?parentid=3772
68.Ziff S, Ziff M. Dentistry without Mercury. IAOMT: ChampionsGate, FL. 2014.
69.Vedantam S. Research links lead exposure, criminal activity. The Washington Post. July 8, 2007. http://www.washingtonpost.com/wp-dyn/content/article/2007/07/07/AR2007070701073.html
70.Goodwin H. Lead exposure and poisoning in children. Southern California Environmental Report Card. UCLA Institute of the Environment and Sustainability. Spring 2009. http://www.environment.ucla.edu/reportcard/article.asp?parentid=3772
71.Vedantam S. Research links lead exposure, criminal activity. The Washington Post. July 8, 2007. http://www.washingtonpost.com/wp-dyn/content/article/2007/07/07/AR2007070701073.html
72.Woods JS, Heyer NJ, Echeverria D, Russo JE, Martin MD, Bernardo MF, Luis HS, Vaz L, Farin FM. Modification of neurobehavioral effects of mercury by a genetic polymorphism of coproporphyrinogen oxidase in children. Neurotoxicol Teratol. 2012; 34(5):513-21.
73.Echeverria D, Aposhian HV, Woods JS, Heyer NJ, Aposhian MM, Bittner AC, Mahurin RK, Cianciola M. Neurobehavioral effects from exposure to dental amalgam Hgo: new distinctions between recent exposure and body burden. FASEBJ. 1998; 12(11):971-980.
74.Echeverria D, Woods JS, Heyer NJ, Rohlman D, Farin F, Li T, Garabedian CE. The association between a genetic polymorphism of coproporphyrinogen oxidase, dental mercury exposure and neurobehavioral response in humans. Neurotoxicol Teratol. 2006; 28(1):39-48.
75.Echeverria D, Heyer N, Martin MD, Naleway CA, Woods JS, Bittner AC. Behavioral effects of low-level exposure to Hg0 among dentists. Neurotoxicol Teratol. 1995; 17(2):161-8.
76.Siblerud RL, Motl J, Kienholz E. Psychometric evidence that mercury from silver dental fillings may be an etiological factor in depression, excessive anger, and anxiety. Psychol Rep. 1994; 74(1):67-80.
77.Bellinger DC, Bellinger AM. Childhood lead poisoning: the torturous path from science to policy. Journal of Clinical Investigation. 2006; 116(4): 853-857.
78.Peeples L. Lead poisoning and the middle class: the silent epidemic that doesn’t discriminate. Huffington Post. March 15, 2013. http://www.huffingtonpost.com/2013/03/15/lead-poisoning-children-middle-class_n_2880619.html
79.Lewis J. Lead poisoning: a historical perspective. EPA Journal. May 1985. United States Environmental Protection Agency Website. http://www2.epa.gov/aboutepa/lead-poisoning-historical-perspective


 

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Occupational Safety and Dental Mercury:
Changing Standards

By David Kennedy, DDS, MIAOMT, and Amanda Just

Overview of the United States Occupational Safety and Health Administration (OSHA)

National standards for occupational safety are founded upon the undeniable fact that industry can kill and seriously harm workers. This concept has been tragically evidenced by a list of veritable disasters, including the development of Caisson’s disease during the Brooklyn Bridge construction, the Triangle Shirtwaist Factory fire, and asbestos exposure from manufacturing.

As a result, the United States and most developed countries of the world have adopted standards for worker protection. Such standards generally state that when it is reasonable to assume a risk is present, the employer is required to take appropriate measures to protect its workers. In the US, this effort was first officially attempted with the OSH Act, which was passed by Congress in 1970.1

However, the OSH Act is clearly a work in progress, which is made especially evident by the Workers’ Right to Know Act of 1987.2 This “addition” to the OSH Act became necessary because in some cases, workers were endangered without their knowledge.

One way the Workers’ Rights provisions can be viewed is that the US Congress decided the best way to deal with occupational hazards was to inform employees so that the workers could protect themselves. Another way to view OSHA standards is that they are not health-based measures; they are lenient enough to accomplish manufacturing goals in a balance between worker safety and the need to get the job done.

In addition to the OSHA standards, many workers are compensated financially for risks by the industry. For example, truck drivers hauling trash are paid less than truckers hauling fuel, and truckers hauling fuel are paid less than those hauling explosives, etc.

At any extent, when it comes to mercury, employee exposure is strictly regulated by the 1970 Occupational Health and Safety Act and the 1987 Right to Know Act which require employers to
• Train employees on how to avoid or minimize exposures
• Offer informed consent at least as detailed as the Material Safety Data Sheet (MSDS)
• Use work practices that minimize toxic release
• Institute engineering controls to minimize toxic exposures
• Provide protective equipment to all exposed employees
• Monitor the facility contaminant levels
• Medically monitor and annually test employees for exposure
• Maintain records of all of the above in their Hazards Communication Notebook

Yet, dental schools cannot use the OSHA standards to protect students because students are not considered employees (i.e. they do not receive wages for their work). However, the instructors, janitors, assistants, and clerks in dental school facilities are covered by OSHA, although it is interesting to consider how many of them have actually been offered informed consent and appropriate training in protecting themselves from mercury.

Overview the United States Environmental Protection Agency (EPA)

The EPA was founded in 1973 after many years of active protests about air and water pollution, and EPA standards are designed to ensure public safety. Before EPA rules were passed, rivers caught on fire and pollution laid waste to vast areas of the land. Air in most major cities frequently became smoggy, a condition which still exists today in countries where such standards either are not enacted or are routinely ignored.

In the US, EPA measures have already been put into place for some industries that use mercury. For example, updated standards to lower mercury emissions from coal-fired power plants were passed as the Mercury and Air Toxics Standards on December 21, 2011. At that time, EPA leader Lisa Jackson explained, “The Mercury and Air Toxics Standards will protect millions of families and children from harmful and costly air pollution and provide the American people with health benefits that far outweigh the costs of compliance.”3

In reference to amalgam fillings, the EPA has recognized that the dental industry emitted “approximately 3.7 tons of mercury each year to POTWs [publicly-owned treatment works]” and that “dental offices were found in 2003 to have been the source of 50 percent of all mercury pollution entering POTWs [publicly-owned treatment works].”4

Furthermore, media reports have suggested that dental offices are the cause of mercury pollution in the water,5 and a local ABC news station in Indiana ran a February 2014 segment about dentists in the city of Elkhart being blamed for high levels of mercury in wastewater and thereafter being asked by the city to use amalgam separators.6

Acknowledgement of this dangerous type of mercury pollution resulted in a September 25, 2014 ruling from the EPA, under the Clean water Act, which now requires dentists to limit mercury releases to the environment by using amalgam separators and best management practices. According to the EPA, this revised standard was developed in part as a result of the United Nations Environment Programme’s 2013 Minamata Convention on Mercury.

Such situations make it clear that dentistry will not be exempt from additional mercury regulations and suggest that it is only a matter of time before more new standards are enacted.

A comparison of Norway’s experiences with occupational safety for dental mercury

Norway was the first country in the world to ban the use of dental amalgam mercury fillings in January 2008 when Norway’s Minister of Environment and Development, Erik Solheim announced, “Mercury is among the most dangerous environmental toxins. Satisfactory alternatives to mercury in products are available, and it is therefore fitting to introduce a ban.”7

Sweden and Denmark also issued bans on mercury fillings later that year.8

Most people are not aware that part of the impetus for the movement against on-the-job injury from dental mercury in Norway was inspired in 1994 by dental nurse Tordis Stigen Klausen, who contacted the Government and the Regional Development and Directorate of Norwegian Labour Inspection (similar to the US’s OSHA). At first, they ignored the problem, and so did the Norwegian Labour and Welfare Service (NAV) when Klausen contacted them in 1995.

In 2005, Klausen was joined by a group of dental nurses who took the initiative and also contacted the Norwegian Labour and Welfare Service (NAV), explaining cases of on-the-job injury, birth abnormalities, and in some cases, even death.

Public perception shifted in favor of Tordis Stigen Klausen and the other dental workers when NRK Brennpunkt, a Norwegian documentary program, aired their story on national television in 2005.9 The program featured a few of the nurses and discussed their health issues. They also interviewed an agency leader who denied that there could be any such problem with mercury in well-regulated dental offices. It was suggested that the female dental workers were merely looking for a handout and were not seriously impaired. However, the night the program first aired, the station received over 450 phone calls from other dental nurses exposed to mercury who had experienced similar abnormal birth outcomes or neurological harm.

To test the validity of these women’s claims, an arrangement was made with the University of Lund in Sweden to evaluate the group for evidence of mercury toxicity. They took on this new task, and in a very short amount of time, they determined that the vast majority of the women and some of their offspring had been injured by on-the-job dental mercury exposure. Furthermore, they established that mercury levels generated during many dental procedures, especially in preparing high copper amalgam fillings, grossly exceeded the nation’s occupational safety standards.

Meanwhile, the NRK television documentary did a follow-up story on the women in 2010 which transpired into public questioning as to how the government agency NAV dealt with the case.10

Finally, in 2012, Tordis Stigen Klausen, a former dental assistant, succeeded in having the NAV officially acknowledge her mercury-related occupational illness. A Norwegian news article by Kjersti Knudsson reporting this event noted that Gerd Bang-Johansen, chair of Norway’s League of Dental Assistants, stated, “We have a huge number of cases to be dealt with in the NAV system and we are going to follow them closely. Many of these women have exactly the same symptoms as Stigen Klausen, and have worked with mercury a lot.”11

After the state appealed the ruling in favor of the dental assistants, Norway’s Supreme Court upheld the decision to officially acknowledge mercury injury as an occupational disease in the case of these women.

Former dental nurse Bertha Regine Serigstad, represented by the Norwegian Union of Municipal and General Employees, also won her case in 2013,12 and Solveig Irene Jacobsen, who worked for a dental service on a boat in northern Norway had her case approved in the NAV system in 2014.13 Many other Norwegian dental workers are following suit.14

Science to support occupational safety measures for dental mercury

A plethora of scientific studies have demonstrated hazards of mercury in the dental workplace, as the following (abbreviated) list shows:
• Handling of dental mercury waste15,16,17
• Health risks for dental workers18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41
• Health risks for dental students42,43
• Health risks for female dental workers44,45,46,47
• Need for safety measures48,49,50,51,52,53,54,55

The Future of Change for Occupation Safety in Dentistry

Each year that passes brings more evidence and data showing that mercury fillings pose risks to dental workers, patients, and the environment. Meanwhile, there is clearly a global trend to phase-down the use of mercury, as aptly evidenced in the 2013 United Nations Minamata Convention on Mercury. Even in the US, recent years have brought various regulations for industrial mercury.

Thus, it seems inevitable that protective measures will be taken for dental mercury over the next decade. The question is whether these changes will focus only on the environment and neglect to take into account the workers who are routinely and closely exposed to the element.

As of now, the responsibility is left to you. After all, as a worker here in the US, it is part of your job to protect yourself. That being said, as a student, you should have already learned how to protect yourself, especially because you are already being exposed to toxic mercury.


1.United States Department of Labor. OSHA Act of 1970. Occupational Safety and Health Administration. OSHA Website. http://www.osha.gov/pls/oshaweb/owasrch.search_form?p_doc_type=OSHACT. Accessed December 15, 2013.
2.Occupational Safety and Health Administration. Workers’ Rights. 2011. OSHA Website. http://www.osha.gov/Publications/osha3021.pdf . Accessed December 15, 2013.
3.United States Environmental Protection Agency. EPA Issues First National Standards for Mercury Pollution from Power Plants/ Historic ‘mercury and air toxics standards’ meet 20-year old requirement to cut dangerous smokestack emissions [press release]. EPA Website. December 21, 2011.
http://yosemite.epa.gov/opa/admpress.nsf/bd4379a92ceceeac8525735900400c27/bd8b3f37edf5716d8525796d005dd086!OpenDocument Accessed December 15, 2013.
4.United States Environmental Protection Agency. Mercury in Dental Amalgam. EPA Website. http://www.epa.gov/hg/dentalamalgam.html#dentists. Accessed December 15, 2013.
5.Reuters Health. Dental offices may be source of mercury pollution. [Source: Environmental Science & Technology.] April 14, 2008. http://www.reuters.com/article/2008/04/14/us-mercury-pollution-idUSCOL47042520080414
6.RTV 6 ABC Indiana. Elkhart targets dentists over mercury in water. February 10, 2014. http://www.theindychannel.com/news/elkhart-targets-dentists-over-mercury-in-water
7.Miller A. Norway becomes first country to ban amalgam fillings. Natural News. April 24, 2008. http://www.naturalnews.com/022943.html
8.Reuters/PRNewswire-USNewswire Online. Dental mercury use banned in Norway, Sweden and Denmark because composites are adequate replacements [press release]. January 3, 2008. http://www.reuters.com/article/idUS108558+03-Jan-2008+PRN20080103.
9.Knudsson K. NAV finally believes mercury victim. Tannhelsesekretærenes Forbund. Oslo, Norway. April 18, 2012. Available at http://www.non-au-mercure-dentaire.org/_fichiers/tordisklausenen_mercury-1.pdf
10.Ibid.
11.Ibid.
12.Velle V. Kvikksølvofrene vant mot staten i Høyesterett. Fagbladet. December 13, 2013. http://www.fagbladet.no/forsiden/kvikkslvofrene_vant_mot_staten_i_hyesterett_228193.html
[English translation available from Public Services International. Mercury victims win Supreme Court case against Norwegian state. PSI website. January 10, 2014. http://www.world-psi.org/en/mercury-victims-win-supreme-court-case-against-norwegian-state
13.Bergsland T. Dental assistants to receive compensation. Tannhelsesekretærenes Forbund. Oslo, Norway. February 19, 2014. http://www.thsf.no/Fullstory.aspx?m=217&amid=2719
14.Velle V. Kvikksølvofrene vant mot staten i Høyesterett. Fagbladet. December 13, 2013. http://www.fagbladet.no/forsiden/kvikkslvofrene_vant_mot_staten_i_hyesterett_228193.html
[English translation available from Public Services International. Mercury victims win Supreme Court case against Norwegian state. PSI website. January 10, 2014. http://www.world-psi.org/en/mercury-victims-win-supreme-court-case-against-norwegian-state
15.Lönnroth EC, Shahnavaz H. Amalgam in dentistry. A survey of methods used at dental clinics in Norrbotten to decrease exposure to mercury vapour. Swed Dent J. 1995; 19(1-2):55.
16.Mumtaz R, Khan AA, Noor N, Humayun S. Amalgam use and waste management by Pakistani dentists: an environmental perspective. East Mediterr Health J. 2010; 16(3).
17.Nazar MW, Pordeus IA, Werneck MAF. Dental waste management in municipal health clinics in Belo Horizonte, Brazil. Rev Panam Salud Publica. 2005; 17(4):237-242. Portuguese.
18.Echeverria D, Heyer N, Martin MD, Naleway CA, Woods JS, Bittner AC. Behavioral effects of low-level exposure to Hg0 among dentists. Neurotoxicol Teratol. 1995; 17(2):161-8.
19.Uzzell BP, Oler J. Chronic low-level mercury exposure and neuropsychological functioning. J Clin Exp Neuropsychol. 1986; 8(5):581-593.
20.Echeverria D, Woods JS, Heyer NJ, Rohlman DS, Farin FM, Bittner AC, Li T, Garabedian C. Chronic low-level mercury exposure, BDNF polymorphism, and associations with cognitive and motor function. Neurotoxicology and teratology. 2005; 27(6):781-796.
21.Ngim CH, Foo SC, Boey KW, Jeyaratnem J. Chronic neurobehavioural effects of elemental mercury in dentists. Br J Ind Med. 1992; 49(11):782-790.
22.Lee JY, Yoo JM, Cho BK, Kim HO. Contact dermatitis in Korean dental technicians. Contact Dermatitis. 2001; 45(1):13-16.
23.Rojas M, Seijas D, Agreda O, Rodríguez M. Biological monitoring of mercury exposure in individuals referred to a toxicological center in Venezuela. Sci Total Environ. 2006; 354(2):278-285.
24.Pérez-Gómez B, Aragonés N, Gustavsson P, Plato N, López-Abente G, Pollán, M. Cutaneous melanoma in Swedish women: occupational risks by anatomic site. Am J Ind Med. 2005; 48(4):270-281.
25.Ahlbom A, Norell S, Rodvall Y, Nylander M. Dentists, dental nurses, and brain tumors. Br. Med. J. 1986; 292(6521):662.
26.Karahalil B, Rahravi H, Ertas N. Examination of urinary mercury levels in dentists in Turkey. Hum Exp Toxicol. 2005; 24(8):383-388.
27.Buchwald H. Exposure of dental workers to mercury. Am Ind Hyg Assoc J. 1972; 33(7):492-502.
28.Martin MD, Naleway C, Chou HN. Factors contributing to mercury exposure in dentists. J Am Dent Assoc. 1995; 126(11):1502-1511.
29.Fabrizio E, Vanacore N, Valente M, Rubino A, Meco G. High prevalence of extrapyramidal signs and symptoms in a group of Italian dental technicians. BMC Neurol. 2007; 7(1):24.
30.Kanerva L, Lahtinen A, Toikkanen J, Forss H, Estlander T, Susitaival P, Jolanki R. Increase in occupational skin diseases of dental personnel. Contact Dermatitis. 1999; 40(2):104-108.
31.Richardson GM. Inhalation of mercury-contaminated particulate matter by dentists: an overlooked occupational risk. Human and Ecological Risk Assessment. 2003; 9(6):1519-1531.
32.Zahir F, Rizwi SJ, Haq SK, Khan RH. Low dose mercury toxicity and human health. Environ Toxicol Pharmacol. 2005; 20(2):351-360.
33.Nylander M, Friberg L, Eggleston D, Björkman L. Mercury accumulation in tissues from dental staff and controls in relation to exposure. Swed Dent J. 1989; 13(6):235-236.
34.Parsell DE, Karns L, Buchanan WT, Johnson RB. Mercury release during autoclave sterilization of amalgam. J Dent Educ. 1996; 60(5):453-458.
35.Goodrich JM, Wang Y, Gillespie B, Werner R, Franzblau A, Basu N. Methylmercury and elemental mercury differentially associate with blood pressure among dental professionals. Int J Hyg Environ Health. 2013; 216(2):195-201.
36.Echeverria D, Aposhian HV, Woods JS, Heyer NJ, Aposhian MM, Bittner AC, Mahurin RK, Cianciola M. Neurobehavioral effects from exposure to dental amalgam Hgo: new distinctions between recent exposure and body burden. FASEBJ. 1998; 12(11):971-980.
37.Shapiro IM, Cornblath DR, Sumner AJ, Sptiz LK, Uzzell B, Ship II, Bloch P. Neurophysiological and neuropsychological function in mercury-exposed dentists. Lancet. 1982; 319(8282):1447-1150.
38.Cooper GS, Parks CG, Treadwell EL, St Clair EW, Gilkeson GS, Dooley MA. Occupational risk factors for the development of systemic lupus erythematosus. J Rheumatol. 2004; 31(10):1928-1933.
39.Hilt B, Svendsen K, Syversen T, Aas O, Qvenild T, Sletvold H, Melø I. Occurrence of cognitive symptoms in dental assistants with previous occupational exposure to metallic mercury. Neurotoxicology. 2009; 30(6):1202-1206.
40.Echeverria D, Woods JS, Heyer NJ, Rohlman D, Farin F, Li T, Garabedian CE. The association between a genetic polymorphism of coproporphyrinogen oxidase, dental mercury exposure and neurobehavioral response in humans. Neurotoxicol Teratol. 2006; 28(1):39-48.
41.Duplinsky TG, Cicchetti DV. The health status of dentists exposed to mercury from silver amalgam tooth restorations. International Journal of Statistics in Medical Research. 2012; 1(1):1-15.
42.White RR, Brandt RL. Development of mercury hypersensitivity among dental students. JADA. 1976; 92(6):1204-7.
43.de Oliveira MT, Pereira JR, Ghizoni JS, Bittencourt ST, Molina GO. Effects from exposure to dental amalgam on systemic mercury levels in patients and dental school students. Photomed Laser Surg. 2010; 28(S2):S-111.
44.Lewczuk E, Affelska-Jercha A, Tomczyk J. Occupational health problems in dental practice. Med Pr. 2002; 53(2):161. Polish.
45.Gelbier S, Ingram J. Possible fetotoxic effects of mercury vapor: a case report. Public Health. 1989; 103(1):35-40.
46.Rowland AS, Baird DD, Weinberg CR, Shore DL, Shy CM, Wilcox AJ. The effect of occupational exposure to mercury vapour on the fertility of female dental assistants. Occupat Environ Med. 1994; 51:28-34.
47.Sikorski R, Juszkiewicz T, Paszkowski T, Szprengier-Juszkiewicz T. Women in dental surgeries: reproductive hazards in exposure to metallic mercury. International Archives of Occupational and Environmental Health. 1987; 59(6):551-557.
48.Yip HK, Li DK, Yau DC. Dental amalgam and human health. Int Dent J. 2003; 53(6):464-8.
49.Lönnroth EC, Shahnavaz H. Dental clinics–a burden to environment? Swed Dent J. 1996; 20(5):173.
50.Morales Fuentes I, Reyes Gil R. Mercury and health in the dental practice. Rev Saude Publica. 2003; 37(2):263-265. Spanish.
51.Rojas M, Guevara H, Rincon R, Rodriguez M, Olivet C. Occupational exposure and health effects of metallic mercury among dentists and dental assistants: a preliminary study. Acta Cient Venez. 2000; 51(1):32-8. Spanish.
52.Grigoletto JC, Oliveira ADS, Muñoz SIS, Alberguini LBA, Takayanagui AMM. Occupational risk due to use of mercury in dentistry: a bibliographic review. Cien Saude Colet. 2008; 13(2):533-542. Portuguese.
53.Nimmo A, Werley MS, Martin JS, Tansy MF. Particulate inhalation during the removal of amalgam restorations. J Prosth Dent. 1990; 63(2):228-33.
54.Warwick R, O Connor A, Lamey B. Sample size = 25 for each mercury vapor exposure during dental student training in amalgam removal. J Occup Med Toxicol. 2013; 8(1):27.
55.Votaw AL, Zey J. Vacuuming a mercury-contaminated dental office may be hazardous to your health. Dent Assist. 1991; 60(1): 27.


 

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PROTECTING THE INNOCENT:
DENTAL AMALGAM MERCURY
AND RISKS TO FETUSES, INFANTS, AND CHILDREN

By David Kennedy, DDS, and Amanda Just

When former dental assistant Karen Palmer testified to the Dental Products Panel of United States Food and Drug Administration (FDA) in 2010, she insisted that they consider pregnant women in their evaluation of dental amalgam mercury fillings. Palmer passionately told the panel, “I witnessed many of my colleagues experience thyroid disease, infertility, spontaneous abortions, miscarriages, and still birth. Most worked through their pregnancy and while nursing, too. Clearly, women in dentistry are not only at the greatest risk from exposure to mercury, but they are not adequately protected by the present standards.”1

Palmer is one of a growing number of citizens around the globe who have taken on the mission of warning others about mercury, a poisonous metallic element known to harm both the environment and humans, especially pregnant women and children, who are considered to be the most susceptible populations for mercury toxicity.

At the same meeting Palmer presented her experiences of suffering with multiple sclerosis and a plethora of other health issues that have been related to occupational exposure to mercury, one of the panel members supported her concerns about children. Dr. Suresh Kotagal a pediatric neurologist at the Mayo Clinic, concluded, “…I think that there is really no place for mercury in children.”2

Similarly, in 2009, 19 members of Congress wrote a letter to the FDA to express their concern about mercury used in amalgam fillings, with a focus on potential dangers to pregnant women and children. Representative Diane Watson of California explained, “It is, in fact, children who are at greatest risk from these fillings.”3

Other authorities have also warned about mercury’s use in children and pregnant women. For example, a World Health Organization report identified areas of risk specifically linked to mercury in children when it noted: “Adverse health effects from mercury exposure can be: tremors, impaired vision and hearing, paralysis, insomnia, emotional instability, developmental deficits during fetal development, and attention deficit and developmental delays during childhood.”4

While health agencies inform the public about the possible presence of mercury in certain types of fish and shellfish and recommend that pregnant women and children restrict these food products in their diet,5,6,7the use of mercury in dentistry continues in the United States. In fact, an FDA warning for dental amalgam mercury use in developing children and fetuses8 was removed from the FDA website in 2009.

However, the governments of Norway, Sweden, and Denmark9 have banned the use of mercury amalgam fillings10 in dentistry, France has recommended that alternative mercury-free dental materials be used for pregnant women,11 and Germany, Finland, Austria, and Canada have worked to reduce the use of dental mercury amalgam fillings for pregnant women, children, and patients with kidney problems.12

Meanwhile, the dangers of fetal exposure to mercury have been scientifically established over the years. A study from 1982 stated, “Previous stillbirths, as well as history of birth defects, exhibited significant positive correlation with background mercury levels.”13

In regards to dental amalgam, research in this area has provided significant data associating the number of maternal amalgam fillings with mercury levels in the kidneys14,15 and liver16 of fetuses, brain17 and kidneys18 of infants, inorganic mercury levels in the placenta,19 mercury in cord blood,20,21 and mercury levels in fetal hair.22

Furthermore, one study about a “thirty-year-old dental surgeon who worked until the 35th week of pregnancy in a surgery in which mercury vapour concentrations in excess of the threshold limit value (TLV) had been detected” reported that she gave birth to a severely brain damaged baby.23 The researchers noted, “Attention is drawn to the need for further research into the effects on health and pregnancy outcome of mercury vapour in dental surgeries.”24

Another trend in research about maternal amalgam fillings are studies that have found the mercury concentration in breast milk increases as the number of amalgam fillings in the mother increases.25,26,27,28

In addition to fetuses and infants, children are also at-risk for health impairments potentially caused by dental amalgam mercury fillings.29,30,31,32,33,34,35,36,37,38,39,40 A study from 2011 cautions, “Changes in dental practices involving amalgam, especially for children, are highly recommended in order to avoid unnecessary exposure to Hg [mercury].”41 Risk assessments have also explored designating safe levels specifically for children, who are smaller and still developing,42 especially since many dose levels are based on a one-size-fits-all scale for both children and adults.

Although two studies (commonly referred to as the “New England Children‘s Amalgam Trial” and the “Casa Pia Children’s Amalgam Trial”) have repeatedly been used to defend the use of amalgam in children, researchers have demonstrated that these studies failed to take essential factors such as long-term effects and genetic predisposition into account.43,44,45,46,47,48,49

While science continues to produce evidence suggesting that dental mercury can cause serious health consequences for pregnant women, fetuses, infants, and children, consumers are also coming to the same conclusion. Like Karen Palmer and Dr. Kotagal, Dorice Madronero offered a grave warning to the 2010 FDA Dental Products Panel: “As a young expectant mother I know that twice following dental work I miscarried. I know that at the time the dentist gave no warning about a mercury exposure. I know that at no point in my visits to the obstetrician was I warned about a mercury exposure, in the dental fillings or asked about my medical and dental history.”50

At the 2010 FDA meeting attended by Palmer, Kotagal, and Madronero, the Dental Products Panel recommended the FDA consider limiting dental mercury amalgam use in pregnant women and children and consider labeling that would warn consumers about the risks of this mercury-containing product.51 An official ruling was expected from the FDA by December 31, 2011,52 but as of the publication of this article, no decision has been made.


1. United States of America Department of Health and Human Services Food and Drug Administration, Center for Devices and Radiological Health Medical Devices Committee.  Dental Products Panel [transcript].  December 14, 2010.  http://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMateria…

2. United States of America Department of Health and Human Services Food and Drug Administration, Center for Devices and Radiological Health Medical Devices Committee. Dental Products Panel [transcript]. December 15, 2010: 271. http://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/MedicalDevices/MedicalDevicesAdvisoryCommittee/DentalProductsPanel/UCM242363.pdf

3. Watson, Diane, Congresswoman, Mercury in Dental Filling Disclosure and Prohibition Act, November 5, 2001, http://amalgamillness.com/Text_DCAct.html.

4. World Health Organization. Mercury in Health Care: Policy Paper. Geneva, Switzerland; August 2005. http://www.who.int/water_sanitation_health/medicalwaste/mercurypolpaper.pdf. Accessed February 17, 2013.

5. United States Environmental Protection Agency. Mercury: Human Exposure, October 2010,1. http://www.epa.gov/hg/exposure.htm

6. State of Connecticut Department of Public Health. A Woman’s Guide to Eating Fish Safely: Special Advice for Pregnant Women & Young Children, 2010, http://www.ct.gov/dph/lib/dph/environmental_health/eoha/pdf/womans_guide_-english_2010.pdf

7. United States Food and Drug Administration. What You Need to Know about Mercury in Fish and Shellfish, 2009.http://www.fda.gov/Food/ResourcesForYou/Consumers/ucm110591.htm

8. Associated Press. Warning issued for silver dental fillings. USA Today. 6/12/2008.

9. Reuters/PRNewswire-USNewswire Online. Dental mercury use banned in Norway, Sweden and Denmark because composites are adequate replacements. January 3, 2008. http://www.reuters.com/article/idUS108558+03-Jan-2008+PRN20080103.

10. Orthomolecular Medicine News Service. Mercury Dental Amalgams Banned in 3 Countries: FDA, EPA, ADA Still Allow and Encourage Heavy-Metal Fillings. November 20, 2008.

http://orthomolecular.org/resources/omns/v04n24.shtml.

11. Health and Environment Alliance. Mercury and Dental Amalgams [fact sheet]. Brussels, Belgium: Health and Environment Alliance and Health Care without Harm; May 2007: 3. http://www.env-health.org/IMG/pdf/HEA_009-07.pdf .

12. Ibid.

13. Kuntz WD, Pitkin RM, Bostrom AW, Hughes MS. Maternal and cord blood background mercury levels: a longitudinal surveillance.  Am J Obstet Gynecol. 1982; 143(4):440-3.

14. Drasch G, Schupp I, Hofl H, Reinke R, Roider G. Mercury burden of human fetal and infant tissues. Eur J Pediatr. 1994; 153(8):607–10.

15. Lutz E, Lind B, Herin P, Krakau I, Bui TH, Vahter M. Concentrations of mercury, cadmium and lead in brain and kidney of second trimester fetuses and infants. J Trace Elem Med Biol. 1996; 10(2):61–7.

16. Drasch G, Schupp I, Hofl H, Reinke R, Roider G. Mercury burden of human fetal and infant tissues. Eur J Pediatr. 1994; 153(8):607–10.

17. Ibid.

18. Ibid.

19. Ask K, Akesson A, Berglund M, Vahter M. Inorganic mercury and methylmercury in placentas of Swedish women. Environ Health Perspect. 2002; 110(5):523-6.

20. Ask-Björnberg K, Vahter M, Petersson-Grawé K, Glynn A, Cnattingius S, Darnerud PO, et al. Methyl mercury and inorganic mercury in Swedish pregnant women and in cord blood: influence of fish consumption. Environ Health Perspect. 2003; 111(4):637–41.

21. Palkovicova L, Ursinyova M, Masanova V, Yu Z, Hertz-Picciotto I. Maternal amalgam dental fillings as the source of mercury exposure in developing fetus and newborn. J Expo Sci Environ Epidemiol. 2008; 18(3):326-331.

22. Lindow SW, Knight R, Batty J, Haswell SJ. Maternal and neonatal hair mercury concentrations: the effect of dental amalgam. Journal of Obstetrics and Gynecology. 2003; 23(S1):S48-S49.

23. Gelbier S, Ingram J.  Possible fetotoxic effects of mercury vapor: a case report. Public Health. 1989; 103(1):35-40.

24. Ibid.

25. Ask-Björnberg K, Vahter M, Petersson-Grawé K, Glynn A, Cnattingius S, Darnerud PO, et al. Methyl mercury and inorganic mercury in Swedish pregnant women and in cord blood: influence of fish consumption. Environ Health Perspect. 2003;111(4): 637–41.

26. da Costa SL, Malm O, Dorea JG. Breast-milk mercury concentrations and amalgam surface in mothers from Brasilia, Brasil. Biol Trace Elem Res. 2005; 106(2): 145–51.

27. Oskarsson A, Schutz A, Schkerving S, Hallen IP, Ohlin B, Lagerkvist BJ. Total and inorganic mercury in breast milk in relation to fish consumption and amalgam in lactating women. Arch Environ Health. 1996; 51(3):234-51.

28. Nourouzi E, Bahramifar N, Ghasempouri SM. Effect of teeth amalgam on mercury levels in the colostrums human milk in Lenjan. Environ Monit Access. 2012; 184(1): 375-380.

29. Geier DA, Carmody T, Kern JK, King PG, Geier MR. A significant dose-dependent relationship between mercury exposure from dental amalgams and kidney integrity biomarkers A further assessment of the Casa Pia children’s dental amalgam trial. Human & Experimental Toxicology. 2013; 32(4):434-440.

30. Guzzi, G; Pigatto, PD. Urinary mercury levels in children with amalgam fillings. Environ Health Perspect. 2008; 116(7):A286-7.

31. Haley, Boyd. Response to the NIDCR Funded Children’s Amalgam Testing publications in the JAMA 2006. IAOMT Web Site. http://www.iaomt.org/articles/category_view.asp?intReleaseID=280&month=9&year=2006&catid=30

32. Geier DA, Carmody T, Kern JK, King PG, Geier MR. A significant relationship between mercury exposure from dental amalgams and urinary porphyrins: a further assessment of the Casa Pia children’s dental amalgam trial. Biometals. 2011; 24, (2):215-224.

33. Al-Saleh I, Al-Sedairi A. Mercury (Hg) burden in children: The impact of dental amalgam. Sci Total Environ. 2011; 409(16):3003-3015.

34. Ask K, Akesson A, Berglund M, Vahter M. Inorganic mercury and methylmercury in placentas of Swedish women. Environ Health Perspect. 2002; 110(5):523-6.

35. Laks DR. Environmental mercury exposure and the risk of autism. White Paper for Safe Minds. August 27, 2008. http://www.safeminds.org/about/documents/SM%20Env%20Mercury%20Exposure%20and%20Risk%20of%20Autism.pdf

36. Vahter M, Akesson A, Lind B, Bjors U, Schutz A, Berglund M. Longitudinal study of methylmercury and inorganic mercury in blood and urine of pregnant and lactating women, as well as in umbilical cord blood. Environ Res. 2000; 84(2):186-94.

37. Holmes, AS, Blaxill, MF, Haley, BE. Reduced levels of mercury in first baby haircuts of autistic children. Int J Toxicol. 2003. 22 (4): 277-85.

38. Haley BE. Mercury toxicity: genetic susceptibility and synergistic effects. Medical Vertias. 2005;2(2): 535-542.

39. Woods JS, Heyer NJ, Echeverria D, Russo JE, Martin MD, Bernardo MF, Luis HS, Vaz L, Farin FM. Modification of neurobehavioral effects of mercury by a genetic polymorphism of coproporphyrinogen oxidase in children. Neurotoxicol Teratol. 2012; 34(5):513-21.

40. Dunn JE, Trachtenberg FL, Barregard L, Bellinger D, McKinlay S. Scalp hair and urine mercury content of children in the northeast United States: the New England children’s amalgam trial. Environ Res. 2008; 107(1):79–88.

41. Al-Saleh I, Al-Sedairi A. “Mercury (Hg) burden in children: The impact of dental amalgam,” Sci Total Environ (2011), doi:10.1016/j.scitotenv.2011.04.047.

42. Richardson GM and Canada. Assessment of mercury exposure and risks from dental amalgam: Final Report. Ottowa:  Medical Devices Bureau; August 18, 1995.

43. Needleman HL. Mercury in dental amalgam—a neurotoxic risk? JAMA. 2006; 295(15):1835-1836.

44.Geier DA, Carmody T, Kern JK, King PG, Geier MR. A dose-dependent relationship between mercury exposure from dental amalgams and urinary mercury levels: a further assessment of the Casa Pia Children’s Dental Amalgam Trial. Human & Experimental Toxicology. 2012; 31(1), 11-17.

45.Guzzi, G; Pigatto, PD.  Urinary mercury levels in children with amalgam fillings. Environ Health Perspect. 2008; 116(7):A286-7.

46. Haley, Boyd. Response to the NIDCR Funded Children’s Amalgam Testing publications in the JAMA 2006. IAOMT document. http://www.iaomt.org/articles/category_view.asp?intReleaseID=280&month=9&year=2006&catid=30

47.Geier DA, Carmody T, Kern JK, King PG, Geier MR. A significant relationship between mercury exposure from dental amalgams and urinary porphyrins: a further assessment of the Casa Pia children’s dental amalgam trial. Biometals. 2011; 24(2):215-224.

48. Duffy, Sandra. Critique of the Children’s Amalgam Study Consent Forms (American forms and Portuguese forms). IAOMT document. http://www.iaomt.org/articles/files/files280/CAT_Duffy_legal_critique.pdf

49.Brown, Charles. Letter to Dr. Schwetz and Dr. Carome. July 5, 2005. Copy available at http://www.iaomt.org/articles/files/files280/Consumers%20for%20Dental%20Choice%20Brief.pdf

50. United States of America Department of Health and Human Services Food and Drug Administration, Center for Devices and Radiological Health Medical Devices Committee. Dental Products Panel [transcript]. December 15, 2010. http://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/MedicalDevices/MedicalDevicesAdvisoryCommittee/DentalProductsPanel/UCM242363.pdf.

51.Ibid.

52. ®andall™. Jeffrey Shuren, director of FDA’s CDRH, will make end year (2011) announcement on dental amalgam. [Video Footage from FDA Townhall Meeting in California.] Uploaded January 8, 2012 by Mercury Exposure.

http://www.youtube.com/watch?v=H2t0J2_1yr0.


 

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WHAT EVERY DENTIST NEEDS TO KNOW
ABOUT METAL ALLERGIES

By David Kennedy, DDS, MIAOMT and Amanda Just

There is no question that patients can be allergic to dental materials used in their mouth, and even the American Dental Association recognizes this health complication.1 While allergic reactions have been reported to a wide-range of products including acrylic resin, resin composite, impression materials, and eugenol-containing products,2 the issue of allergies to dental metals is an area of growing concern. A 2011 article by Hosoki and Nishigawa explains why dentists should be educated about this possible side effect: “Current data indicate that practicing dentists need to obtain further specialized knowledge about dental metal allergy in order to ensure the correct treatment of patients in their clinics.”3

Dr. Steve Koral, a practicing IOAMT dentist, knows from first-hand experience how essential it is for dentists to learn about metal allergies. Patients have sought him out for his expertise in this area, and he notes that these individuals “are immensely grateful when their dentist acknowledges the problem when prescribing dental materials. After all, people can manage food sensitivities by rotating the diet, but they can’t rotate their permanently installed artificial fillings.”

There are a variety of estimates as to how many patients suffer from allergies to dental metals. A 1993 study by Inoue reported that 3.9% of healthy subjects tested positive for metal reactions.4 If this figure is applied to the current US population,5 this would mean that dental metal allergies potentially impact as many as 12.4 million Americans. Yet, the figure could be even higher because more recent studies and reports tend to agree that dental metal allergies are on the rise.6,7 A 2007 article in Nature specifically warns of reactions in dental patients wearing braces and goes on to describe a study from Singapore that found nickel allergies increased from 14% in 1984 to 20% in 2003.8

Nickel allergies have received a great deal of attention due to their prevalence. Research has demonstrated that approximately 10% of women and 1-2% of men are allergic to this metal.9,10 Because of the high number of female patients potentially impacted, nickel has been considered by some to be the dental material most likely to cause allergic reactions in American women.11

A number of other dental metals are also known to cause problems for sensitive and allergic patients. The first case of report of dental metal allergies offered clinically was in 1928 due to the mercury in amalgam fillings.12 Since that time, in addition to mercury and nickel, allergies have been documented for dental metals such as titanium, gold, chromium, platinum, cobalt, stannum (tin), beryllium, and cadmium. Typically, reactions occur in the mouth, but they can also occur on the hands, feet, and other parts of the body.13

Researchers are currently delving deeper into understanding the complex factors that lead to the development of metal allergies. Genetics are one variable being studied,14,15,16,17 and some researchers predict that specific genotypes will be correlated with adverse immune responses to metals.18 Additionally, there is an overall consensus that T-cells in the immune system trigger the negative reactions.

Furthermore, ionization of metals appears to play a major role in allergies. While a “stable” metal is generally regarded as non-reactive, if ionization of the metal occurs, this can cause an allergic response. In the oral cavity, ionization can result from pH changes initiated by saliva and diet.19 The electrolytic conditions can also cause corrosion of the dental metals and generate electrical currents in a phenomenon known as oral galvanism.20 Not surprisingly, oral galvanism has likewise been established as a factor in sensitivities to dental metals.21,22,23,24

Researchers at Tohoku University in Japan are also exploring the role of molecules known as lipopolysaccharides in metal allergies. Dr. Endo and his team theorize that lipopolysaccharides in bacteria can cause an allergic reaction to metals, as Endo described in a 2008 article in Nature: “‘If people come in contact with a metal during infection, I speculate that this could lead them to develop metal allergies later in life.’”25

Nature reporter Matt Kaplan went on to explain this concept, “This implies that a complex made of lipopolysaccharides and nickel may be the thing that triggers the immune system, which then becomes sensitive to any kind of lipopolysaccharide-metal complex. If so, then wearing a nickel bracelet during an infection may predispose you to a silver allergy later in life.”26

Indeed, jewelry has been mentioned as part of the reason dental metal allergies are increasing. In their 2011 article, Hosoki and Nishigawa explain that the growing popularity of ear piercing since the 1990’s could be part of the cause for the rise in dental metal allergies.27 This is because being exposed to a metal increases the chance for the allergy to develop, so the current body piercing trend could mean that even more allergies are occurring. In fact, Hosoki and Nishigawa cite a study by Jensen purporting that after Denmark imposed nickel regulations, there was a decline in nickel sensitivities among Danish girls who had pierced ears.28

However, one issue with calculating the number of patients with a negative reaction to a metallic material is that the onset of symptoms can be delayed and therefore might not be associated with the exposure. Hosoki and Nishigawa have noted that a minimum of one week is necessary to assess metal allergy test results, and research by Djerassi and Berova about amalgam allergies warns, “Sensitization appears most frequently after the amalgam has been present in the mouth for more than 5 years.”29

Another issue is the wide-range of symptoms patients allergic to dental metals can exhibit. The most commonly reported side effects from a dental metal allergy include pustulosis palmaris and dyshidrotic eczema (usually in the form of erythema, blisters, and scaly and crusty skin), lichen planus (usually in the form of spots on the skin), glossodynia (usually in the form of pain or burning of the tongue), generalized eczema and pseudoatopic dermatitis (usually in the form of an itching rash), and atopic dermatitis (chronic eczema with itching).30

Yet, a gamut of other health conditions has also been linked to dental metal allergies. These include oral lichenoid lesions,31,32,33,34 autoimmunity,35,36 chronic fatigue syndrome,37,38,39 multiple chemical sensitivities,40,41 metallic pigmentation,42 myalgic encephalitis,43 orofacial granulomatosis,44 fibromyalgia,45 multiple sclerosis,46 and even infertility in both women and men.47

Moreover, a 2006 study of patients diagnosed with intraoral squamous cell carcinoma found that dental metal allergies are a potential factor for this type of cancer.48 A summary of the researchers’ results explains this serious health risk: “Ten patients (91%) had positive patch tests to metals. In eight (73%), the oral cancer was adjacent to a dental restoration containing a metal to which the patient was allergic. Prevalence of gold, mercury, silver, and copper allergy among these patients was substantially higher than that reported in the available worldwide patch-test clinic population.”49

In addition to patients exhibiting allergic responses to dental metals placed in their mouths, research has also shown that dental personnel working with these metals are at risk for developing metal allergies. This includes dentists,50 dental technicians,51 and dental students.52,53 While the researchers of one of these studies did not consider their results to be significant, their data correlated dental students’ allergies to mercury with the number of their own amalgam fillings.54

In the past, testing for allergies was most often conducted by skin patch testing. The method is still commonly used today, but because it requires applying the potential allergen to the skin, and some people might be highly reactive to such an application, there is controversy about this technique.55 Another problem with skin patch testing is evaluating what constitutes an allergic reaction since there are such a wide variety of symptoms and since the onset of these symptoms56 can be delayed. Patch testing detects type 1, immediate hypersensitivity, and many symptoms of immune reaction to metals are a result of type IV, delayed hypersensitivity.

One relatively new alternative to skin patch testing is known as the Lymphocyte Transformation Test (LTT), which was first used in the 1960s to evaluate certain types of antigens. In 1994, Stejskal introduced the MELISA test, a modified version of the LLT designed to test for metal sensitivity type IV delayed hypersensitivity to metals, including sensitivity to mercury.57 This blood test is gaining popularity because it does not expose patients to the same materials that could be making them ill.

Another option for testing has been created specifically for dental materials. If this biological testing is used, a patient’s blood sample is sent to a laboratory where the serum is evaluated for the presence of IgG and IgM antibodies to the chemical ingredients used in dental products.58 The patient is then provided with a detailed list of which name-brand dental materials are safe for their use and which ones could result in a reaction. Two labs that currently offer this service are Clifford Consulting and Research59 and Biocomp Laboratories.60

As far as recovery from symptoms related to dental metal allergies, there is promising research that suggests in some cases, patients improve or are cured of their reactions after removal of the material suspected to be causing the allergy. Conditions reportedly improved and cured as a result of removing dental metal allergens include eczema,61 dermatitis,62,63 chronic fatigue syndrome,64 multiple sclerosis,65 orofacial granulomatosis,66 oral lichen planus,67,68,69 and oral lichenoid lesion.70,71,72 In their 2011 report, Hosoki and Nishigawa suggest, “In principle, all restorations with allergy-positive metal elements need to be removed.”73

It is important to note here that removal of any metallic dental material requires a number of precautions. For example, Hosoki and Nishigawa provide recommendations for prioritizing which dental materials should be removed first, as well as advice for being very careful of metal dust exposures and the use of a patient dam during the removal process. The IAOMT has also created a safe protocol for removal of amalgam fillings, including the use of masks, cold water irrigation, high volume suction, and other protective techniques.*

Dr. Steve Koral of the IAOMT hopes that dentists and dental students will expand their knowledge of dental metal allergies and safe removal processes so that even more patients will experience better dental and overall health. He explains, “By practicing individualized biocompatibility testing, and making other common sense choices, we can (almost) always find a combination of professionally recognized restorative materials that will do the job. We can fix teeth and at the same time help our patients avoid toxicity, immune reactivity, and galvanic stress, and just as important, provide them with peace of mind.”74

* The IAOMT’s protocol for safe removal of amalgam fillings is located online at https://iaomt.org/safe-removal-amalgam-fillings/


1. American Dental Association. Dental Filling Facts [brochure]. ADA Website. http://www.ada.org/sections/publicResources/pdfs/dental_fillings_facts_full.pdf
2.Wiltshire WA, Ferreira MR, Ligthelm AJ. Allergies to dental materials. Quintessence International- English edition. 1996; 27: 513-520. http://www.quintpub.com/userhome/qi/qi_27_8_wiltshire_11.pdf
3.Hosoki M, Nishigawa K. Book Chapter “Dental Metal Allergy” in Contact Dermatitis, edited by Young Suck Ro, ISBN 978-953-307-577-8, InTech, December 12, 2011. http://www.intechopen.com/download/get/type/pdfs/id/25247
4.Inoue M. The Status Quo of Metal Allergy and Measures Against it in Dentistry,
J.Jpn.Prosthodont.Soc. 1993; (37): 1127-1138.
As cited in Hosoki M, Nishigawa K. Book Chapter “Dental Metal Allergy” in Contact Dermatitis, edited by Young Suck Ro, ISBN 978-953-307-577-8, InTech, December 12, 2011. http://www.intechopen.com/download/get/type/pdfs/id/25247
5.United States Census Bureau. Census Bureau Projects U.S. Population of 317.3 Million on New Year’s Day [press release]. December 30, 2013. http://www.census.gov/newsroom/releases/archives/population/cb13-tps112.html
http://www.census.gov/newsroom/releases/archives/population/cb13-tps112.html
6.Hosoki M, Nishigawa K. Book Chapter “Dental Metal Allergy” in Contact Dermatitis, edited by Young Suck Ro, ISBN 978-953-307-577-8, InTech, December 12, 2011. http://www.intechopen.com/download/get/type/pdfs/id/25247
7.Kaplan M. Infections may trigger metal allergies. Nature. May 2, 2007. http://www.nature.com/news/2007/070430/full/news070430-6.html
8.Goon AJ et al. Contact Dermatitis. 2005; 52:130 – 132.
As cited in Kaplan M. Infections may trigger metal allergies. Nature. May 2, 2007. http://www.nature.com/news/2007/070430/full/news070430-6.html
9.Wiltshire WA, Ferreira MR, Ligthelm AJ. Allergies to dental materials. Quintessence International- English edition. 1996; 27: 513-520. http://www.quintpub.com/userhome/qi/qi_27_8_wiltshire_11.pdf
10.Ad Hoc Subcommittee on the Benefits of Dental Amalgam. Biocompatibility of dental restorative materials. Health.gov Website. http://web.health.gov/environment/amalgam1/appendixI-sectionIII.htm
11. Wiltshire WA, Ferreira MR, Ligthelm AJ. Allergies to dental materials. Quintessence International- English edition. 1996; 27: 513-520. http://www.quintpub.com/userhome/qi/qi_27_8_wiltshire_11.pdf
12.Fleischmann P. Zur Frage der Gefährlichkeit Kleinster Quecksilbermengen. Dtsch Med Wochen scher. 1928; (54): 304.
As cited in Hosoki M, Nishigawa K. Book Chapter “Dental Metal Allergy” in Contact Dermatitis, edited by Young Suck Ro, ISBN 978-953-307-577-8, InTech, December 12, 2011. http://www.intechopen.com/download/get/type/pdfs/id/25247
13.Hosoki M, Nishigawa K. Book Chapter “Dental Metal Allergy” in Contact Dermatitis, edited by Young Suck Ro, ISBN 978-953-307-577-8, InTech, December 12, 2011. http://www.intechopen.com/download/get/type/pdfs/id/25247
14.Stejskal VDM, Cederbrant K, Lindvall A, Forsbeck M. MELISA—an in vitro tool for the study of metal allergy. Toxicology in vitro. 1994; 8(5): 991-1000.
15.Zamm A. Dental mercury: a factor that aggravates and induces xenobiotic intolerance. Journal of Orthomolecular Medicine. 1991; (6)2.
16.Stejskal VDM, Cederbrant K, Lindvall A, Forsbeck M. MELISA—an in vitro tool for the study of metal allergy. Toxicology in vitro. 1994; 8(5): 991-1000.
17.Stejskal I, Danersund A, Lindvall A, Hudecek R, Nordman V, Yaqob A, Mayer W, Bieger W, Lindh U. Metal-specific lymphocytes: biomarkers of sensitivity in man. Neuroendocrinol Lett. 1999; 20(5):289-298.
18.Enestrom S, Hultman P. Does amalgam affect the immune system? A controversial issue. International Archives of Allergy and Immunology. 1995; 106(3):180-191.
19.Hosoki M, Nishigawa K. Book Chapter “Dental Metal Allergy” in Contact Dermatitis, edited by Young Suck Ro, ISBN 978-953-307-577-8, InTech, December 12, 2011. http://www.intechopen.com/download/get/type/pdfs/id/25247
20.Ziff S, Ziff M. Dentistry without Mercury. IAOMT: ChampionsGate, FL. 2014.
21.Ditrichova D, Kapralova S, Tichy M, Ticha V, Dobesova J, Justova E, Eber M, Pirek P. Oral lichenoid lesions and allergy to dental materials. Biomedical Papers. 2007; 151(2): 333-339.
22.Athavale PN, Shum KW, Yeoman CM, Gawkrodger DJ. Oral lichenoid lesions and contact allergy to dental mercury and gold. Contact Dermatitis. 2003; 49(5):264-265.
23.Pigatto PDM, Brambilla L, Ferrucci S, Guzzi G. Systemic allergic contact dermatitis due to galvanic couple between mercury amalgam and titanium implant. Skin Allergy Meeting. 2010.
24.Koral S. A practical guide to compatibility testing for dental materials. IAOMT Website. http://iaomt.org/practical-guide-compatibility-testing-dental-materials/
25.Kaplan M. Infections may trigger metal allergies. Nature. May 2, 2007. http://www.nature.com/news/2007/070430/full/news070430-6.html
26.Ibid.
27.Hosoki M, Nishigawa K. Book Chapter “Dental Metal Allergy” in Contact Dermatitis, edited by Young Suck Ro, ISBN 978-953-307-577-8, InTech, December 12, 2011. http://www.intechopen.com/download/get/type/pdfs/id/25247
28.Jensen CS, Lisby S, Baadsgaard O, Volund A, Menne T. Decrease in nickel sensitization in a Danish schoolgirl population with ears pierced after implementation of a nickel-exposure regulation. Br J Dermatol. 2002; (146): 636-42.
As cited in Hosoki M, Nishigawa K. Book Chapter “Dental Metal Allergy” in Contact Dermatitis, edited by Young Suck Ro, ISBN 978-953-307-577-8, InTech, December 12, 2011. http://www.intechopen.com/download/get/type/pdfs/id/25247
29.Djerassi E, Berova N. The possibilities of allergic reactions from silver amalgam restorations. Internat Dent J. 1969; 19(4):481-8.
30.Hosoki M, Nishigawa K. Book Chapter “Dental Metal Allergy” in Contact Dermatitis, edited by Young Suck Ro, ISBN 978-953-307-577-8, InTech, December 12, 2011. http://www.intechopen.com/download/get/type/pdfs/id/25247
31.Ditrichova D, Kapralova S, Tichy M, Ticha V, Dobesova J, Justova E, Eber M, Pirek P. Oral lichenoid lesions and allergy to dental materials. Biomedical Papers. 2007; 151(2): 333-339.
32.Wong L, Freeman S. Oral lichenoid lesions (OLL) and mercury in amalgam fillings. Contact Dermatitis. 2003; 48(2):74-79.
33.Laine J, Kalimo K, Forssell H, Happonen R. Resolution of oral lichenoid lesions after replacement of amalgam restorations in patients allergic to mercury compounds. JAMA. 1992; 267(21):2880.
34.Pang BK, Freeman S. Oral lichenoid lesions caused by allergy to mercury in amalgam fillings. Contact Dermatitis. 1995; 33(6):423-7.
35.Stejskal VDM, Cederbrant K, Lindvall A, Forsbeck M. MELISA—an in vitro tool for the study of metal allergy. Toxicology in vitro. 1994; 8(5): 991-1000.
36.Prochazkova J, Sterzl I, Kucerova H, Bartova J, Stejskal VD. The beneficial effect of amalgam replacement on health in patients with autoimmunity. Neuro Endocrinol Lett. 2004; 25(3):211-218.
37.Stejskal VDM, Cederbrant K, Lindvall A, Forsbeck M. MELISA—an in vitro tool for the study of metal allergy. Toxicology in vitro. 1994; 8(5): 991-1000.
38.Stejskal I, Danersund A, Lindvall A, Hudecek R, Nordman V, Yaqob A, Mayer W, Bieger W, Lindh U. Metal-specific lymphocytes: biomarkers of sensitivity in man. Neuroendocrinol Lett. 1999; 20(5):289-298.
39.Sterzl I, Procházková J, Hrdá P, Bártová J, Matucha P, Stejskal VD. Mercury and nickel allergy: risk factors in fatigue and autoimmunity. Neuro Endocrinol Lett. 1999; 20:221-228.
40.Stejskal I, Danersund A, Lindvall A, Hudecek R, Nordman V, Yaqob A, Mayer W, Bieger W, Lindh U. Metal-specific lymphocytes: biomarkers of sensitivity in man. Neuroendocrinol Lett. 1999; 20(5):289-298.
41.Koral S. A practical guide to compatibility testing for dental materials. IAOMT Website. http://iaomt.org/practical-guide-compatibility-testing-dental-materials/
42.Venclikova Z, Benada O, Bartova J, Joska L, Mrklas L, Prochazkova J, Stejskal V, Podzimek S. In vivo effects of dental casting alloys. Neuro Endocrinol Lett. 2006; 27:61.
43.Stejskal I, Danersund A, Lindvall A, Hudecek R, Nordman V, Yaqob A, Mayer W, Bieger W, Lindh U. Metal-specific lymphocytes: biomarkers of sensitivity in man. Neuroendocrinol Lett. 1999; 20(5):289-298.
44.Tomka M, Machovkova A, Pelclova D, Petanova J, Arenbergerova M, Prochazkova J. Orofacial granulomatosis associated with hypersensitivity to dental amalgam. Science Direct. 2011; 112(3):335-341.
45.Sterzl I, Procházková J, Hrdá P, Bártová J, Matucha P, Stejskal VD. Mercury and nickel allergy: risk factors in fatigue and autoimmunity. Neuro Endocrinol Lett. 1999; 20:221-228.
46.Prochazkova J, Sterzl I, Kucerova H, Bartova J, Stejskal VD. The beneficial effect of amalgam replacement on health in patients with autoimmunity. Neuro Endocrinol Lett. 2004; 25(3):211-218.
47.Podzimek S, Prochazkova J, Buitasova L, Bartova J, Ulcova-Gallova Z, Mrklas L, Stejskal VD. Sensitization to inorganic mercury could be a risk factor for infertility. Neuro Endocrinol Lett. 2005; 26(4):277-282.
48.Hougeir FG, Yiannias JA, Hinni ML, Hentz JG, el-Azhary RA. Oral metal contact allergy: a pilot study on the cause of oral squamous cell carcinoma. Int J Dermatol. 2006; 45(3):265-271.
49.Ibid.
50.White RR, Brandt RL. Development of mercury hypersensitivity among dental students. JADA. 1976; 92(6):1204-7.
51.Lee JY, Yoo JM, Cho BK, Kim HO. Contact dermatitis in Korean dental technicians. Contact Dermatitis. 2001; 45(1):13-16.
52.White RR, Brandt RL. Development of mercury hypersensitivity among dental students. JADA. 1976; 92(6):1204-7.
53.Miller, EG, Perry WL, Wagner MJ. Prevalence of mercury hypersensitivity in dental students. J Dent Res. 1987; 58(2):235-7.
54.Ibid.
55.Ziff S, Ziff M. Dentistry without Mercury. IAOMT: ChampionsGate, FL. 2014.
56.Ibid.
57.Stejskal, V. D. M., et al. “MELISA—an in vitro tool for the study of metal allergy.” Toxicology in vitro 8.5 (1994): 991-1000.
58.Koral S. A practical guide to compatibility testing for dental materials. IAOMT Website. http://iaomt.org/practical-guide-compatibility-testing-dental-materials/
59.Clifford Consulting and Research Website is http://www.ccrlab.com/
60.Biocomp Laboratories Website is http://www.biocomplabs.com/about.html
61.Hosoki M, Nishigawa K. Book Chapter “Dental Metal Allergy” in Contact Dermatitis, edited by Young Suck Ro, ISBN 978-953-307-577-8, InTech, December 12, 2011. http://www.intechopen.com/download0/get/type/pdfs/id/25247
62.Pigatto PDM, Brambilla L, Ferrucci S, Guzzi G. Systemic allergic contact dermatitis due to galvanic couple between mercury amalgam and titanium implant. Skin Allergy Meeting. 2010.
63.Hosoki M, Nishigawa K. Book Chapter “Dental Metal Allergy” in Contact Dermatitis, edited by Young Suck Ro, ISBN 978-953-307-577-8, InTech, December 12, 2011. http://www.intechopen.com/download/get/type/pdfs/id/25247
64.Stejskal VDM, Cederbrant K, Lindvall A, Forsbeck M. MELISA—an in vitro tool for the study of metal allergy. Toxicology in vitro. 1994; 8(5): 991-1000.
65.Prochazkova J, Sterzl I, Kucerova H, Bartova J, Stejskal VD. The beneficial effect of amalgam replacement on health in patients with autoimmunity. Neuro Endocrinol Lett. 2004; 25(3):211-218.
66.Tomka M, Machovkova A, Pelclova D, Petanova J, Arenbergerova M, Prochazkova J. Orofacial granulomatosis associated with hypersensitivity to dental amalgam. Science Direct. 2011; 112(3):335-341.
67.Lundstrom IM. Allergy and corrosion of dental materials in patients with oral lichen planus. Int J Oral Surg. 1984; 13(1):16.
68.Lind PO, Hurlen B, Lyberg T, Aas E. Amalgam-related oral lichenoid reaction. Scand J Dent Res. 1986; 94(5):448-51.
69.Finne KAJ, Göransson K, Winckler L. Oral lichen planus and contact allergy to mercury. International Journal of Oral Surgery. 1982; 11(4):236-239.
70.Laine J, Kalimo K, Forssell H, Happonen R. Resolution of oral lichenoid lesions after replacement of amalgam restorations in patients allergic to mercury compounds. JAMA. 1992; 267(21):2880.
71.Pang BK, Freeman S. Oral lichenoid lesions caused by allergy to mercury in amalgam fillings. Contact Dermatitis. 1995; 33(6):423-7.
72.Camisa C, Taylor JS, Bernat JR, Helm TN. Contact hypersensitivity to mercury in amalgam restorations may mimic oral lichen planus. Cutis. 1999; 63(3):189-92.
73.Hosoki M, Nishigawa K. Book Chapter “Dental Metal Allergy” in Contact Dermatitis, edited by Young Suck Ro, ISBN 978-953-307-577-8, InTech, December 12, 2011. http://www.intechopen.com/download/get/type/pdfs/id/25247
74.Koral S. A practical guide to compatibility testing for dental materials. IAOMT Website. http://iaomt.org/practical-guide-compatibility-testing-dental-materials/


 

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OLD HABITS DIE HARD:
THE CONTINUED USE OF ARSENIC AND LEAD IN DENTISTRY

By David Kennedy, DDS, MIAOMT, and Amanda Just

Less than thirty years ago, most food packaging did not include a list of ingredients and nutritional facts. However, consumers and other groups demanded this information be disclosed, and in 1990, food labeling became a requirement by the United States Food and Drug Administration (FDA).1 Yet, even before this legislation was passed, Ulf Bengtsson, a research engineer at Linköping University in Sweden, had been working to accomplish this type of open disclosure for dental products, and his years of analyzing the issue have produced many reasons why detailed ingredient lists of dental materials for medical professionals and consumers are essential.

In 1990, Bengtsson wrote an article about the toxic composition of some endodontic materials,2 and his report attracted publicity from the Swedish press. Most people were not aware that for many decades, arsenic and other poisons were commonly used for dental treatments, and they were likewise shocked that Bengtsson suggested the materials were sometimes still being used. After his paper received attention and discussion, Bengtsson says that health authorities assured him the harmful ingredients had been removed from practice.

Yet, in January 2014, Bengtsson once again discovered that outdated, poisonous dental materials were easily available. For example, the catalogue of a Swiss company named Produits Dentaires,3 which has distributors in the United States,4 included a number of such items. At least one item, Devitec AS, was removed from their online catalogue in early 2014, although it could still be on the shelf of dealers and dentists. At any extent, a further search of the internet in 2014 produced additional manufacturers selling toxic dental products of the past.5678

Arsenic and other poisonous endodontic treatments

When Shearjashup Spooner endorsed the use of arsenic for killing pulp as part of endodontic treatments in 1836,9 the practice became accepted in dentistry. Arsenic is now known to be carcinogenic10 and is one of WHO’s “10 chemicals of major public health concern” due to its toxicity.11 A 1974 article published in Oral Surgery, Oral Medicine, Oral Pathology, and Oral Radiology described the historical use of arsenic and other noxious chemicals in root canal treatment:

Highly irritating caustic chemicals such as sulfuric acid, phenosulfonic acid and hydrochloric acid were used as adjuncts in enlarging root canals. Additionally, chemicals such as formocresol, phenol, camphorated chlorphenol, eugenol and ammoniated silver nitrate solution were used as intracanal medicaments. Pulp mummification was performed by first placing arsenic and then using paraformaldehyde over the dead pulp tissue. Root canals were filled with cotton moistened with creosote, tricresol-formalin, or an essential oil such as Blacks 1,2,3 or oil of cinnamon or cassia. In other cases, canals were filled with gutta-percha and a paste to which thymoliodide was added.12

The use of arsenic in dentistry drastically declined as the twentieth century progressed, especially after complications and cases of bone necrosis were reported. That being said, for obvious reasons, Bengtsson was frustrated in 2014 to find again that these antiquated products were still being sold, usually without warning to the dentist or disclosure to the patient.

Unfortunately, research has confirmed Bengtsson’s concern, and a 2013 study from Italy featured a case study of a patient who had been treated with arsenic in 2012.13 Demonstrating the dangerous fact that this product is still being allowed and applied, the researchers conclude, “Arsenic compounds cause severe consequence and should not be used in endodontic practice.”14

Additionally, an April 2014 press release from the European Medicines Agency (EMA) suggested revoking the marketing authorizations for two dental arsenic-containing products. Specifically, the EMA release states:

In a review of the benefits and risks of these dental products, analyses of data from laboratory and population studies indicate that the arsenic contained in them may pose a risk of genotoxic effects that could increase the risk of cancer. In addition, there have been a small number of cases where arsenic is thought to have leaked into the areas around the teeth, causing parts of the tissue to die, including bone (osteonecrosis).15

Lead in crowns, bridges, and dentures

One way lead was used in past dental practices was for endodontic treatments developed by Pierre Fauchard in 172816 and Leonard Koecker in 1820.17 Since then, lead has been removed from paints and other products because of its known hazards to the nervous system, kidneys, and reproductive system.18 However, a 2008 news story by Lee Howard of The Day identified the issue of modern dental materials being contaminated with lead.19

Howard’s article mentioned an Ohio woman who had help from her local TV station in discovering that her negative response to a dental bridge, manufactured in China, could have been caused by the fact it had lead in it, as did a number of other dental crowns that were eventually tested.20

Similar to Bengtsson’s concerns about the simplicity of ordering toxic products from companies around the globe, Howard’s report offered an estimate given from one of the directors of the National Association of Dental Laboratories about dental materials shipped to the US: “‘…about 15 to 20% of all crowns, bridges, and dentures in the United States are now manufactured offshore – and the percentage is rising every year.’”21

These statistics and examples offer evidence as to why dentists and consumers need to be aware of the ingredients used to create crowns, bridges, and dentures, especially if they are being constructed in countries that might not have the same safety standards as the United States.

Other poisonous dental products

In addition to arsenic, lead, and endodontic materials such as creosote, cresol, paraformaldehyde, and phenol, Bengtsson is also concerned about the continued use of other poisonous dental products including old copper amalgams, radioactive compounds in dental materials, and formocresol in children.

Furthermore, he is concerned about how the common use of toxic dental products in the past can still be impacting people’s health today. For example, asbestos was used in periodontal dressings beginning in 1923.22 According to the United States Occupational Safety and Health Administration (OSHA), asbestos is a group of minerals used in products to “resist heat and corrosion.”23 OSHA also states, “The inhalation of asbestos fibers by workers can cause serious diseases of the lungs and other organs that may not appear until years after the exposure has occurred.”24

A 2009 investigation published in the British Dental Journal reported that asbestos-containing periodontal dressing was still regularly being used in the 1970’s:

In 1976, the American Dental Association Council on Dental Therapeutics took the decision to no longer accept these products, although producing a statement that ‘there is no apparent health danger from inhalation to patients for whom asbestos containing periodontal dressings are used since the fibres cannot be appreciably released from the dressings whilst they are mixed and applied.’ At that time, the article goes on to conclude, there were only ‘several commercially available preparations on the market’ which did not contain asbestos.25

The same 2009 investigation revealed that even in 1991, it was not unusual for students at dental schools to cast dentures, some of which were done using asbestos fiber. The researchers warn, “It follows that if it takes 35 to 40 years for symptoms to materialize, then many dentists, dental assistants and technicians may well become symptomatic with respiratory problems now that maybe attributable to using these powders and rolls in the past.”26

Indeed, there have been reports of dentists suffering from asbestos illness such as mesothelioma, and researchers have suggested that this could be related to the presence of asbestos in periodontal dressings.27

Next steps

Bengtsson continues to evaluate and collect information about harmful practices of the past, as well as toxic ingredients used today such as the mercury in dental amalgam. A portion of his research has been conducted by using patents and scientific articles written about different dental products and procedures since he reports that finding information about the ingredients from other sources has been imprecise and of poor quality.28

In some ways, Bengtsson’s work was validated by a November 2013 policy paper from the Council of European Dentists. The paper acknowledges that the signing of the United Nations Environmental Programme’s Minamata Convention on Mercury has encouraged the phase-down of dental mercury, and it also includes a statement about the need for evaluating alternative materials.

Two areas included in this statement can be applied to listing the ingredients of dental products:

• The first one states, “The profession urges manufacturers to fully declare the chemical composition of the alternative materials.”29
• The second one establishes, “In the best interest of the patient, dental professionals should consider not choosing to use a material where the manufacturer has not made a full qualitative declaration of its chemical composition.”30

Bengtsson suggests this same policy be applied to all dental materials, even ones that are supposedly not being used anymore. He explains, “When the National Board of Health and Welfare [Sweden] said the products I mentioned were removed from use some years ago, I argued that is not relevant. What is, however, is if there are patients out there who still have these materials in their bodies or were exposed to them. This means it could be argued that materials used at least 80 years ago are still relevant.”

Copyright © 2014 IAOMT. All rights reserved.

Many of the key references cited in this article are available upon request to the author: davidkennedydds@gmail.com


 

1. Duffy D. Ingredient Labeling Laws. OLR Research Report. June 5, 2008. Connecticut General Assembly Website. http://www.cga.ct.gov/2008/rpt/2008-R-0334.htm
2. Bengtsson U. Dental Materials in Endodontic Therapy. Linköping University, Institute of Technology, Department of Mechanical Engineering. 1990.
3. Produits Dentaires. Preparations and medicaments for dental use. Supplementary Catalogue 8.3. Produits Dentaires Website. http://www.pdsa.ch/pages_en/flipbook/catalogue%20medical/flipbook.html. Accessed January 2014.
4. Produits Dentaires. Distributors: List of Distributors: United States. Produits Dentaires Website. http://www.pdsa.ch/index_en.php# . Accessed January 2014.
5. Calsun Website. 2008. http://sightime.com/prototype/calsun2010/downloads.html . Accessed January 2014.
6. Biologica Website. 2013. http://www.biologica.co.za/dental-supplies/root-canal-treatment/ . Accessed January 2014.
7. Indiamart. Copper Amalgam. 2013. http://trade.indiamart.com/details.mp?offer=4312572362 . Accessed January 2014.
8. Catalog.md. Yranicid Arsenical Drug Information. 2014. http://www.catalog.md/drugs/yranicid-arsenical.html . Accessed May 2014.
9. Castellucci A. A Brief History of Endodontics. Endodontics. Prato, Italy, 2-5. http://www.endoexperience.com/filecabinet/Texbook%20Exerpts/Castellucci%20Text/chapter_01.pdf
10. Agency for Toxic Substances and Disease Registry. Arsenic. CAS ID #: 7440-38-2. ATSDR Website: Toxic Substances Portal. http://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=3
11. World Health Organization. Arsenic. Fact sheet N°372. WHO Website. http://www.who.int/mediacentre/factsheets/fs372/en/
12. Grossman LI. Endodontics: a peep into the past and the future. Oral Surg Oral Med Oral Pathol. 1974; 37(4):599-608. Evidence-based Endodontics Literature Database:
http://www.evidencebasedendo.com/index.cfm?fuseaction=pub.article&aid=138
13. Giudice A, Cristofaro MG, Barca I, Novembre D, Giudice M. Mandibular bone and soft tissues necrosis caused by an arsenical endodontic preparation treated with piezoelectric device. Case reports in dentistry. 2013.
14. Ibid.
15. European Medicines Agency. EMA recommends revoking authorisations of Caustinerf
arsenical and Yranicid arsenical used in dental procedures. EMA Press Release. April 25, 2014. http://www.ema.europa.eu/docs/en_GB/document_library/Press_release/2014/04/WC500165671.pdf
16. Cruse WP, Bellizzi R. A historic review of endodontics, 1689-1963, part 1. History of Endodontics. 1980; 6(3):495-9. Evidence-based Endodontics Literature Database:
http://www.evidencebasedendo.com/index.cfm?fuseaction=pub.article&aid=137
17. Castellucci A. A Brief History of Endodontics. Endodontics. Prato, Italy, 2-5. http://www.endoexperience.com/filecabinet/Texbook%20Exerpts/Castellucci%20Text/chapter_01.pdf
18. Agency for Toxic Substances and Disease Registry. Lead: ToxFAQs for Lead.. CAS# 7439-92-1. ATSDR Website: Toxic Substances Portal. http://www.atsdr.cdc.gov/toxfaqs/TF.asp?id=93&tid=22
19. Howard L. Lead in dental work prompts fears about Chinese-made crowns, bridges. The Day. April 28, 2008. University of Connecticut Health Center News Archive: http://today.uchc.edu/headlines/2008/apr08/dental_work.html
20. Ibid.
21. Ibid.
22. David K, Shetty N, Pralhad S. Periodontal Dressings: An Informed View. Journal of Pharmaceutical and Biomedical Sciences. 2013; 26(26): 269-272.
23. Occupational Safety and Health Administration. Asbestos Fact Sheet. OSHA FACT Sheet. OSHA Website. https://www.osha.gov/OshDoc/data_AsbestosFacts/asbestos-factsheet.pdf
24. Ibid.
25. Fry C. An investigation into asbestos related disease in the dental industry. British Dental Journal. 2009; 206(10), 515-516.
26. Ibid.
27. Ibid.
28. Bengtsson U. Radioactive Compounds in Dental Materials. 2000.
29. Council of European Dentists. Environmental Management of Dental Materials: Responsible Practice 2013 Update. November 22, 2013. http://eudental.eu/library/104/files/CED-DOC-2013-075-FIN-E-20131126-1916.pdf
30. Ibid.


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The Dentist’s Health:
Evaluating Occupational Risks
from the Use of Amalgam

By David Kennedy, DDS, MIAOMT and Amanda Just

Every occupation exposes workers to chronic conditions and situations that have an impact on overall health. For example, violin players and other musicians are known to suffer high rates of carpal tunnel syndrome (a musculoskeletal injury) due to the repetitive hand movements and positioning often used when playing their instruments.1 Obviously, dentistry also involves routine techniques and materials that can result in health issues. Fortunately, in the same way musicians can change their practices to protect themselves from some of the adverse effects of carpal tunnel, dentists can also change their practices to protect themselves from certain occupational health risks.

Specifically, among the materials regularly handled in dental offices, mercury stands out as a notoriously harmful substance. In fact, a report from the World Health Organization warns, “It may cause harmful effects to the nervous, digestive, respiratory, immune systems and to the kidneys, besides causing lung damage…Recent studies suggest that mercury may have no threshold below which some adverse effects do not occur.” 2

Many dentists, dental staff, and dental students do not realize that a variety of procedures involving manipulation of an old or new amalgam can expose them to levels of mercury that pose an immediate threat to their health unless they take precautions such as instituting work practices and engineering controls to minimize exposure. Research has confirmed adverse outcomes in dentists and dental personnel attributed to occupational mercury vapor and amalgam particulate exposure. This is largely because dangerous levels of mercury are generated in the dental workplace by numerous everyday procedures.3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Scientific evidence has associated mercury with a variety of human health problems, including loss of IQ with prenatal exposure,20 and likewise, research on dentists, dental students, and dental workers has established that toxic harm can occur. 21 To illustrate this point, a 2012 study from Yale University School of Medicine’s Dr.Thomas G. Duplinsky and Dr. Domenic V. Cicchetti reports a high rate of the use of prescription medication in male dentists and relates it to occupational mercury exposure:

Dentists demonstrated significantly more prescription utilization of specific illness medications than did Controls, for the following categories: Neuropsychological, Neurological, Respiratory, and Cardiovascular. The greater majority of pediatric and general practice dentists still use mercury amalgam restorations. This places them at greater risk than the general population for those disorders, as well as threatening the future health of America’s children and adults who continue to receive silver amalgam restorations.

feb2014

A series of other studies have validated this concern, as data has shown that exposure to mercury can cause behavioral, psychological, and cognitive impacts on dental workers.22 23 24 25 26 27

Moreover, genetic variables have been linked to dental workers, mercury levels, and neurobehavioral factors. A common genetic trait known as the CPOX4 polymorphism has been identified as a factor in neurological damage from extremely low mercury exposure in dentists and dental personnel,28 as well as in children with amalgam fillings.29 Another study conducted on dental workers even explains that “chronic sub toxic levels of inorganic mercury appear to produce mild changes in short-term nonverbal recall and heightened distress generally, and particularly in categories of obsessive compulsion, anxiety and psychoticism.” 30

Furthermore, mercury is also known for being toxic to the kidney, and Germany, Finland, Austria, and Canada have worked to reduce the use of dental mercury amalgam fillings for patients with kidney problems and other populations.31 To relate this issue to dental workers, consider the results of a 1988 study which evaluated kidney function in dental personnel exposed to mercury compared to workers exposed to lead, cadmium, and chromium. The study concluded that the dentists and dental assistants appeared to have a higher risk of kidney function disturbance than the other industrial workers.32 A study using sheep found a remarkable decline in kidney function within just two months of receiving multiple amalgam fillings.33 More recently, loss of kidney function has also been linked to the number and size of amalgam fillings.34 35

Another area that has received much attention is the possible reproductive hazards to female dental personnel. It is known that mercury can have a damaging influence on the developing brain and neurological system, which impacts children, pregnant women, and women of childbearing age.36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Thus, the dangers of exposure to mercury for pregnant dental workers have been recognized,61 62 as well as fertility issues63 and menstrual cycle disorders.64

Other research confirms reproductive dangers caused by occupational use of mercury. The Illinois Teratogen Information Service has reported that pregnant women should avoid all significant mercury exposure and recommended greater caution for women of childbearing age.65 A 1999 study from Canada noted, “Pregnant women should not work in areas with high levels of mercury vapor. The recommended threshold limit value of 0.05 ug/m3 for mercury vapor may not provide sufficient protection for fetuses. Therefore, women of childbearing age should not be exposed to mercury vapor concentrations of 0.01mg/m3 or greater.” 66

Dental workers and risks of reactions to mercury or mercury allergies have also been studied. It is estimated that approximately 21 million Americans are allergic to mercury,67 and studies establish that exposure to dental mercury amalgam correlates with higher prevalence of mercury allergies.68 69 70 Not surprisingly, reactions to mercury have been related to dental personnel for dermatitis,71 melanoma,72 and skin diseases. 73 One study even specifies hazards of mercury allergies for dental students: “The fact that the dental students who were the volunteers in this study received only a small fraction of the exposure to mercury that the practicing dentist receives does emphasize the potential of this allergen in actual dental practice.” 74

In addition to the concerns about mercury levels in the dental office and the exposure of workers there,75 76 77 78 79 80 81 82 83 84 a variety of studies have called for protective measures to be taken in the dental office as a means of limiting mercury releases. 85 86 87 88 89 90 91 A 2013 study led by Dr. Robin Warwick states, “To maximize safety, dental schools should train students to remove amalgam only while using water spray and high volume suction. Alternatively, students should use appropriate occupational hygiene personal protective equipment during amalgam removals.” 92 Unfortunately, many dental students cannot comply with these work practices and engineering controls in their operative technique laboratories.

Taken together, scientific data clearly indicates that the use of mercury in dentistry can be detrimental to dentists and their staff. Many factors contribute to increased incidences of disease and health conditions among dentists, but mercury poisoning is a threat that can be easily avoided by the use of current alternatives to amalgam filling materials.

Perhaps a 2003 study by risk assessment expert Dr. G. Mark Richardson summarizes this issue perfectly: “Various countries are moving to limit the use of amalgam as a dental restorative material in order to protect dental patients from Hg [mercury] exposure. However, dentists’ occupational exposure should also be considered as a justification for reduced amalgam use.” 93

Copyright © 2014 IAOMT. All rights reserved.

Many of the key references cited in this article are available upon request to the author: davidkennedydds@gmail.com

 


  1. Hand and arm injuries: Carpal tunnel syndrome.  Part 4: Musculoskeletal injuries (MSIs) prevalent in performers. http://www.mesacc.edu/~juafj03991/cis105/lectures/carpal_tunnel.pdf
  2. World Health Organization.  Mercury in Health Care: Policy Paper.  Geneva, Switzerland; August 2005.  http://www.who.int/water_sanitation_health/medicalwaste/mercurypolpaper.pdf.  Accessed February 17, 2013.
  3. Richardson GM.  Inhalation of mercury-contaminated particulate matter by dentists: an overlooked occupational risk. Human and Ecological Risk Assessment. 2003; 9(6): 1519-1531.
  4. Stonehouse CA, Newman AP.  Mercury vapour release from a dental aspirator. Br Dent J. 2001; 190(10): 558-560.
  5. Windham B.  Research: occupational mercury poisoning in dentistry. The Natural Recovery Planhttp://www.thenaturalrecoveryplan.com/articles/research-mercury-dentistry.html. Accessed February 18, 2013.
  6. White RR, Brandt RL. Development of mercury hypersensitivity among dental students. JADA. 1976; 92(6):1204-7.
  7. Nimmo A, Werley MS, Martin JS, Tansy MF. Particulate inhalation during the removal of amalgam restorations. J Prosth Dent. 1990; 63(2):228-33.
  8. Fabrizio E, Vanacore N, Valente M, Rubino A, Meco G. High prevalence of extrapyramidal signs and symptoms in a group of Italian dental technicians.  BMC Neurol.  2007; 7(1): 24.
  9. Iano FG, Sobrinho S, Silva TLD, Pereira MA, Figueiredo PJM, Alberguini LBA, Granjeiro JM. Optimizing the procedure for mercury recovery from dental amalgam. Braz Oral Res.  2008; 22(2): 119-124.
  10. Johnson KF. Mercury hygiene. Dent Clin North Am.  1978; 22(3): 477.
  11. Lönnroth EC, Shahnavaz H. Amalgam in dentistry. A survey of methods used at dental clinics in Norrbotten to decrease exposure to mercury vapour. Swed Dent J.  1995; 19(1-2): 55.
  12. Lönnroth EC, Shahnavaz H. Dental clinics–a burden to environment?  Swed Dent J.  1996; 20(5): 173.
  13. Martin MD, Naleway C, Chou HN. Factors contributing to mercury exposure in dentists. J Am Dent Assoc.  1995; 126(11): 1502-1511.
  14. Mumtaz R, Khan AA, Noor N, Humayun S. Amalgam use and waste management by Pakistani dentists: an environmental perspective. East Mediterr Health J.  2010; 16(3).
  15. Parsell DE, Karns L, Buchanan WT, Johnson RB. Mercury release during autoclave sterilization of amalgam. J Dent Educ.  1996; 60(5): 453-458.
  16. Roberts HW, Leonard D, Osborne J. Potential health and environmental issues of mercury-contaminated amalgamators. J Am Dent Assoc.  2001; 132(1): 58-64.
  17. Rowe NH, Sidhu KS, Chadzynski L, Babcock RF. Potential public health risks related to mercury/amalgam discharge from dental offices.  J Mich Dent Assoc.  1996; 78(2): 32.
  18. Votaw AL, Zey J. Vacuuming a mercury-contaminated dental office may be hazardous to your health. Dent Assist.  1991; 60(1): 27.
  19. Zahir F, Rizwi SJ, Haq SK, Khan RH. Low dose mercury toxicity and human health. Environ Toxicol Pharmacol.  2005; 20(2): 351-360.
  20. Trasande L, Landrigan P, and Schechter C.  Public health and economic consequences of methyl mercury toxicity to the developing brain.   Environmental Health Perspectives.  2005; 113(5).
  21. Duplinsky TG, Cicchetti DV. The health status of dentists exposed to mercury from silver amalgam tooth restorations. International Journal of Statistics in Medical Research. 2012; 1(1):1-15.
  22. Echeverria D, Heyer N, Martin MD, Naleway CA, Woods JS, Bittner AC. Behavioral effects of low-level exposure to Hg0 among dentists. Neurotoxicol Teratol. 1995; 17(2):161-8.
  23. Ngim CH, Foo SC, Boey KW, Jeyaratnem J. Chronic neurobehavioural effects of elemental mercury in dentists. Br J Ind Med. 1992; 49(11):782-790.
  24. Echeverria D, Aposhian HV, Woods JS, Heyer NJ, Aposhian MM, Bittner AC, Mahurin RK, Cianciola M. Neurobehavioral effects from exposure to dental amalgam Hgo: new distinctions between recent exposure and body burden.  FASEBJ. 1998; 12(11):971-980.
  25. Shapiro IM, Cornblath DR, Sumner AJ, Sptiz LK, Uzzell B, Ship II, Bloch P.  Neurophysiological and neuropsychological function in mercury-exposed dentists.  Lancet.  1982; 319(8282):1447-1150.
  26. Hilt B, Svendsen K, Syversen T, Aas O, Qvenild T, Sletvold H, Melø I. Occurrence of cognitive symptoms in dental assistants with previous occupational exposure to metallic mercury. Neurotoxicology. 2009; 30(6):1202-1206.
  27. Gonzalez-Ramirez D, Maiorino RM, Zuniga-Charles M, Xu Z, Hurlbut KM, Junco-Munoz P, Aposhian MM, Dart RC, Diaz Gama JH, Echeverria D. Sodium 2, 3-dimercaptopropane-1-sulfonate challenge test for mercury in humans: II. Urinary mercury, porphyrins and neurobehavioral changes of dental workers in Monterrey, Mexico. Journal of Pharmacology and Experimental Therapeutics. 1995; 272(1):264-274.
  28. Echeverria D, Woods JS, Heyer NJ, Rohlman D, Farin F, Li T, Garabedian CE.  The association between a genetic polymorphism of coproporphyrinogen oxidase, dental mercury exposure and neurobehavioral response in humans. Neurotoxicol Teratol. 2006; 28(1):39-48.
  29. Woods JS, Heyer NJ, Echeverria D, Russo JE, Martin MD, Bernardo MF, Luis HS, Vaz L, Farin FM.  Modification of neurobehavioral effects of mercury by a genetic polymorphism of coproporphyrinogen oxidase in children. Neurotoxicol Teratol. 2012; 34(5):513-21.
  30. Uzzell BP, Oler J. Chronic low-level mercury exposure and neuropsychological functioning. J Clin Exp Neuropsychol. 1986; 8(5):581-593.
  31. Health and Environment Alliance.  Mercury and Dental Amalgams [fact sheet]. Brussels, Belgium: Health and Environment Alliance and Health Care without Harm; May 2007: 3. http://www.env-health.org/IMG/pdf/HEA_009-07.pdf
  32. Verschoor MA, Herber RF, Zielhuis RL. (1988). Urinary mercury levels and early changes in kidney function in dentists and dental assistants. Community dentistry and oral epidemiology. 1988; 16(3):148-152.
  33. Boyd, N.D.;Benediktsson, H.;Vimy, M.J.; Hooper, D.E.;Lorscheider, F.L.  Mercury from dental “silver” tooth fillings impairs sheep kidney function Am J Physiol. 1991 Oct;261(4 Pt 2):R1010-4.
  34. Al-Saleh I, et al. Effect of mercury (Hg) dental amalgam fillings on renal and oxidative stress biomarkers in children. Sci Total Environ. 2012 Jun 7;431C:188-196.
  35. Geier DA, et al., A significant dose-dependent relationship between mercury exposure from dental amalgams and kidney integrity biomarkers: a further assessment of the Casa Pia children’s dental amalgam trial. Human and Experimental toxicology 1-7 (2012)
  36. Watson, Diane, and 18 other members of Congress.  Dear Acting Commissioner Dr. Joshua Sharfstein… [Congressional letter].  Washington, D.C.: May 14, 2009.  Copy of letter available upon request to john.donnelly@mail.house.gov.
  37. Watson, Diane (Congresswoman). Mercury in Dental Filling Disclosure and Prohibition Act. Los Angeles, CA: November 5, 2001. Copy of Act available at http://amalgamillness.com/Text_DCAct.html.
  38. Rowland AS, Baird DD, Weinberg CR, Shore DL, Shy CM, Wilcox AJ. The effect of occupational exposure to mercury vapour on the fertility of female dental assistants. Occupat Environ Med. 1994; 51:28-34.
  39. Geier DA, Kern JK, Geier MR.  A prospective study of prenatal mercury exposure from dental amalgams and autism severity. Neurobiolgiae Experimentals Polish Neuroscience Society.  2009; 69(2): 189-197.
  40. London S. Amalgam fillings during pregnancy linked to infant cleft palate.  Elsevier Global Medical News.  July 21, 2010.  http://www.medconnect.com.sg/tabid/92/s4/Obstetrics-Gynecology/p21/Pregnancy-Lactation/ct1/c37751/Amalgam-Fillings-During-Pregnancy-Linked-to-Infant-Cleft-Palate/Default.aspx. Accessed February 18, 2013.
  41. Laks DR.  Environmental Mercury Exposure and the Risk of Autism.  White Paper for Safe Minds.  August 27, 2008.  http://www.safeminds.org/about/documents/SM%20Env%20Mercury%20Exposure%20and%20Risk%20of%20Autism.pdf. Accessed February 18, 2013.
  42. Ask K, Akesson A, Berglund M, Vahter M. Inorganic mercury and methylmercury in placentas of Swedish women. Environ Health Perspect. 2002; 110(5):523-6.  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1240842/pdf/ehp0110-000523.pdf. Accessed February 18, 2013.
  43. Vahter M, Akesson A, Lind B, Bjors U, Schutz A, Berglund M.  Longitudinal study of methylmercury and inorganic mercury in blood and urine of pregnant and lactating women, as well as in umbilical cord blood. Environ Res. 2000; 84(2):186-94.
  44. Nourouzi E, Bahramifar N, Ghasempouri SM.  Effect of teeth amalgam on mercury levels in the colostrums human milk in Lenjan. Environ Monit Access.  2012; 184(1):375-380.
  45. Al-Saleh I, Al-Sedairi A. Mercury (Hg) burden in children: The impact of dental amalgam. Sci Total Environ. 2011; 409(16):3003-3015.
  46. Vimy MJ, Hooper DE, King WW, Lorscheider FL. Mercury from maternal “silver” tooth fillings in sheep and human breast milk. Biological Trace Element Research. 1997; 56(2): 143-152.
  47. Richardson GM, Wilson R, Allard D, Purtill C, Douma S, Gravière J. Mercury exposure and risks from dental amalgam in the US population, post-2000. Science of the Total Environment. 2011; 409(20): 4257-4268.
  48. Vimy MJ, Takahashi Y, Lorscheider FL.  Maternal-fetal distribution of mercury (203 Hg) released from dental amalgam fillings. American Physiology Society. 1990; 258(4): R939-945.
  49. Haley BE. Mercury toxicity: genetic susceptibility and synergistic effects. Medical Vertias. 2005; 2(2): 535-542.
  50. Sikorski R, Juszkiewicz T, Paszkowski T, Szprengier-Juszkiewicz T. Women in dental surgeries: reproductive hazards in exposure to metallic mercury. International Archives of Occupational and Environmental Health. 1987; 59(6): 551-557.
  51. Oskarsson A, Schutz A, Schkerving S, Hallen IP, Ohlin B, Lagerkvist BJ. Total and inorganic mercury in breast milk in relation to fish consumption and amalgam in lactating women. Arch Environ Health. 1996; 51(3):234-51.
  52. Dunn JE, Trachtenberg FL, Barregard L, Bellinger D, McKinlay S. Scalp hair and urine mercury content of children in the northeast United States: the New England children’s amalgam trial. Environ Res. 2008;107(1):79–88.
  53. Woods JS, Heyer NJ, Echeverria D, Russo JE, Martin MD, Bernardo MF, Luis HS, Vaz L, Farin FM.  Modification of neurobehavioral effects of mercury by a genetic polymorphism of coproporphyrinogen oxidase in children. Neurotoxicol Teratol. 2012; 34(5):513-21.
  54. Palkovicova L, Ursinyova M, Masanova V, Yu Z, Hertz-Picciotto I. Maternal amalgam dental fillings as the source of mercury exposure in developing fetus and newborn. J Expo Sci Environ Epidemiol. 2008; 18(3):326–31.
  55. Lindow SW, Knight R, Batty J, Haswell SJ. Maternal and neonatal hair mercury concentrations: the effect of dental amalgam. Journal of Obstetrics and Gynecology. 2003; 23(S1):S48-S49.
  56. Lutz E, Lind B, Herin P, Krakau I, Bui TH, Vahter M. Concentrations of mercury, cadmium and lead in brain and kidney of second trimester fetuses and infants. J Trace Elem Med Biol. 1996; 10(2):61–7.
  57. Ask-Björnberg K, Vahter M, Petersson-Grawé K, Glynn A, Cnattingius S, Darnerud PO, et al. Methyl mercury and inorganic mercury in Swedish pregnant women and in cord blood: influence of fish consumption. Environ Health Perspect. 2003; 111(4): 637–41.
  58. da Costa SL, Malm O, Dorea JG. Breast-milk mercury concentrations and amalgam surface in mothers from Brasilia, Brasil. Biol Trace Elem Res. 2005; 106(2): 145–51.
  59. Woods JS, Heyer NJ, Echeverria D, Russo JE, Martin MD, Bernardo MF, Luis HS, Vaz L, Farin FM.  Modification of neurobehavioral effects of mercury by a genetic polymorphism of coproporphyrinogen oxidase in children. Neurotoxicol Teratol. 2012; 34(5):513-21.
  60. Watson GE, Evans K, Thurston SW, van Wijngaarden E, Wallace JM, McSorley EM, Bonham MP, Mulhern MS, McAfee AJ, Davidson PW, Shamlaye CF, Strain JJ, Love T, Zareba G, Myers GJ.  Prenatal exposure to dental amalgam in the Seychelles Child Development Nutrition Study: Associations with neurodevelopmental outcomes at 9 and 30 months.  Neurotoxicology.  2012.
  61. Wasylko L, Matsui D, Dykxhoorn SM, Rieder MJ, Weinberg S. A review of common dental treatments during pregnancy: implications for patients and dental personnel. J Can Dent Assoc. 1998; 64(6):434-9.
  62. Gelbier S, Ingram J.  Possible fetotoxic effects of mercury vapor: a case report. Public Health. 1989; 103(1):35-40.
  63. Rowland AS, Baird DD, Weinberg CR, Shore DL, Shy CM, Wilcox AJ. The effect of occupational exposure to mercury vapour on the fertility of female dental assistants. Occupat Environ Med. 1994; 51:28-34.
  64. Sikorski R, Juszkiewicz T, Paszkowski T, Szprengier-Juszkiewicz T. Women in dental surgeries: reproductive hazards in exposure to metallic mercury. International Archives of Occupational and Environmental Health. 1987; 59(6):551-557.
  65. McMahon C, Pergament E. Illinois Teratogen Information Service. Mercury exposure and Pregnancy. 2001;  8(3).
  66. Moienafshari R, Bar-Oz B, Koren G.  Occupational exposure to mercury.  What level is safe?  Canadian Family Physician. 1999; 46: 43-45.
  67. Amalgam-Mercury Fact Sheet. IAOMT Web site: http://iaomt.guiadmin.com/wp-content/uploads/IAOMT-Fact-Sheet.pdf.  Published August 5, 2011. http://iaomt.guiadmin.com/wp-content/uploads/IAOMT-Fact-Sheet.pdf
  68. Miller EG, Perry WL, Wagner MJ. Prevalence of mercury hypersensitivity in dental students. J Dent Res. 1985; 64: Special Issue, p. 338, Abstract #1472.
  69. White RR, Brandt RL. Development of mercury hypersensitivity among dental students. JADA. 1976; 92(6):1204-7.
  70. Finne KAJ, Göransson K, Winckler L. Oral lichen planus and contact allergy to mercury. International Journal of Oral Surgery.  1982; 11(4):236-239.
  71. Lee JY, Yoo JM, Cho BK, Kim HO. Contact dermatitis in Korean dental technicians. Contact Dermatitis. 2001; 45(1):13-16.
  72. Pérez-Gómez B, Aragonés N, Gustavsson P, Plato N, López-Abente G, Pollán, M. Cutaneous melanoma in Swedish women: occupational risks by anatomic site. Am J Ind Med. 2005; 48(4):270-281.
  73. Kanerva L, Lahtinen A, Toikkanen J, Forss H, Estlander T, Susitaival P, Jolanki R. Increase in occupational skin diseases of dental personnel. Contact Dermatitis. 1999; 40(2):104-108.
  74. White RR, Brandt RL. Development of mercury hypersensitivity among dental students. JADA. 1976; 92(6):1204-7.
  75. Rojas M, Seijas D, Agreda O, Rodríguez M. Biological monitoring of mercury exposure in individuals referred to a toxicological center in Venezuela. Sci Total Environ. 2006; 354(2):278-285.
  76. de Oliveira MT, Pereira JR, Ghizoni JS, Bittencourt ST, Molina GO. Effects from exposure to dental amalgam on systemic mercury levels in patients and dental school students. Photomed Laser Surg.  2010; 28(S2):S-111.
  77. Karahalil B, Rahravi H, Ertas N. Examination of urinary mercury levels in dentists in Turkey. Hum Exp Toxicol. 2005; 24(8):383-388.
  78. Martin MD, Naleway C, Chou HN. Factors contributing to mercury exposure in dentists. J Am Dent Assoc. 1995; 126(11):1502-1511.
  79. Fabrizio E, Vanacore N, Valente M, Rubino A, Meco G. High prevalence of extrapyramidal signs and symptoms in a group of Italian dental technicians. BMC Neurol. 2007; 7(1):24.
  80. Richardson GM.  Inhalation of mercury-contaminated particulate matter by dentists: an overlooked occupational risk. Human and Ecological Risk Assessment. 2003; 9(6):1519-1531.
  81. Zahir F, Rizwi SJ, Haq SK, Khan RH. Low dose mercury toxicity and human health. Environ Toxicol Pharmacol. 2005; 20(2):351-360.
  82. Richardson GM, Brecher RW, Scobie H, Hamblen J, Samuelian J, Smith C. Mercury vapour (Hg(0)): Continuing toxicological uncertainties, and establishing a Canadian reference exposure level. Regul Toxicol Pharmacol. 2009; 53(1):32-38.
  83. Shapiro IM, Cornblath DR, Sumner AJ, Sptiz LK, Uzzell B, Ship II, Bloch P.  Neurophysiological and neuropsychological function in mercury-exposed dentists.  Lancet.  1982; 319(8282):1447-1150.
  84. Windham, B.  Research: occupational mercury poisoning in dentistry. The Natural Recovery Plan.  http://www.thenaturalrecoveryplan.com/articles/research-mercury-dentistry.html
  85. Lönnroth EC, Shahnavaz H. Amalgam in dentistry. A survey of methods used at dental clinics in Norrbotten to decrease exposure to mercury vapour. Swed Dent J. 1995; 19(1-2):55.
  86. Lönnroth EC, Shahnavaz H. Dental clinics–a burden to environment?  Swed Dent J. 1996; 20(5):173.
  87. Buchwald H.  Exposure of dental workers to mercury. Am Ind Hyg Assoc J. 1972; 33(7):492-502.
  88. Parsell DE, Karns L, Buchanan WT, Johnson RB. Mercury release during autoclave sterilization of amalgam. J Dent Educ. 1996; 60(5):453-458.
  89. Stonehouse CA, Newman AP. Mercury vapour release from a dental aspirator. Br Dent J. 2001; 190(10):558-60.
  90. Nimmo A, Werley MS, Martin JS, Tansy MF. Particulate inhalation during the removal of amalgam restorations. J Prosth Dent. 1990; 63(2):228-33.
  91. Roberts HW, Leonard D, Osborne J. Potential health and environmental issues of mercury-contaminated amalgamators. J Am Dent Assoc. 2001; 132(1): 58-64.
  92. Warwick R, O Connor A, Lamey B. Sample size = 25 for each mercury vapor exposure during dental student training in amalgam removal. J Occup Med Toxicol. 2013; 8(1):27.
  93. Richardson GM.  Inhalation of mercury-contaminated particulate matter by dentists: an overlooked occupational risk. Human and Ecological Risk Assessment. 2003; 9(6):1519-1531.