Part II: Mercury Amalgam Fillings

Mike Godfrey MBBS


First published in Organic NZ, January/February 2010 Vol 69 No 1 -

Reprinted here with permission from Physicians and Scientists for Global Responsibility (PSGR) who provide the material for the ONZ Science Watch page.


For the past 160 years a battle has been waged between scientists, together with doctors and even dentists, against a dental establishment that has perversely maintained that dental mercury amalgam, the euphemistically called “silver” amalgam, is a safe and inert alloy. Indeed, the dental establishment maintains that only those who are allergic to mercury can be affected.

However, like arsenic, mercury is an accumulative poison and no one would logically maintain that you can swallow some arsenic every day with enduring safety unless allergic to it as eventually you will become ill. An amalgam filling is about 50% mercury combined with a powder of silver, copper, zinc and tin and a large filling can have as much mercury as in a thermometer.

According to the Word Health Organisation, the average daily accumulated mercury from dental amalgam (up to eight average sized fillings) in the non-industrially exposed population is 3 - 17 micrograms compared to a maximum of 2.6 micrograms for all other sources combined.[1]

Tolerable levels of mercury

In 1996, Health Canada released the findings of a commissioned study into mercury vapour from amalgam.[2] Their Health Department researchers concluded that, based on industrial safety levels and the proven levels of mercury vapour escaping from amalgam, the maximum tolerable daily intake (TDI) would be reached with four average-sized fillings in a 70kg adult and just one filling in a small child.

Predictably, this caused uproar in the dental and insurance industries. They persuaded the bureaucrats that a “Stakeholders” meeting had to be convened where their lawyers subsequently persuaded them to water down the proposed directive to a toothless “advisory” that stated that it was inadvisable to place amalgam fillings in small children; in pregnant or breast-feeding mothers; in those with kidney disease; in the mouth with any other metals; and in those who were sensitive to mercury (without defining how these people were going to be identified).

Swedish phase-out of amalgam

In 1992, the Swedish Government had decided to phase out dental amalgam over a five year period and subsequently amended the Act to make amalgam replacement a medical procedure and thus State-subsidised when a doctor made a clinical diagnosis of mercury poisoning. However, ten years later, as many people were still complaining that they could not get their doctors to accept that they were being poisoned, the Act was further amended to have subsidised amalgam replacement for anyone who thought that they were poisoned without having to get a medical certificate from a doctor who did not believe them.

Mercury toxicity and poisoning

In 1994, Jenny Shipley, the then Health Minister, requested that the author be invited to contribute to a New Zealand Government White Paper on “Dental Amalgam and Human Health” as the only physician and the only one with any clinical experience in mercury toxicity. I was able to include the Canadian findings in the final version,[3] but as the leading author was Dr Cutress, the Director of Dental Research, and the second, the Director of Dental Services, the published “consensus” concluded that amalgam was still safe and useful. Subsequently, Cutress requested that an independent, randomised investigation into the hundreds of patients that I had maintained had greatly benefited from my diagnosis and treatment be done to disprove my conclusions.

However, a Wellington psychologist’s subsequent findings revealed a 95% success rate in all those who had followed both the dental and medical procedures.[4] Many of these patients had been ill for years with, variously, chronic fatigue, headaches, depression, panic attacks, undue irritability and memory loss, all of which were, in fact, listed as adverse reactions in amalgam manufacturers’ package inserts and literature that also listed hypertension and kidney disease. Notably, another listed adverse effect was “resistance to criticism”.[5]

There is a strong association between mercury from amalgam and the increased risk of early onset Alzheimer’s dementia[6] as well as depression, chronic fatigue and memory loss.[7,8]

FDA says amalgam safe – but has conflict of interest

Despite these and numerous similar research papers appearing in the international peer-reviewed literature, they have been dismissed by Health Department’s Advisors and, most recently, by the New Zealand Health Select Committee. The latter’s decision could also have been influenced by the recent US Food and Drug Administration (FDA) classifying amalgam as safe.

However, according to US lawyer, C Brown, representing a patient lobby group, it appears that Margaret Hamburg, the recently appointed FDA Commissioner who headed the committee, had been paid US$250,000 a year by Henry Schein, the largest US manufacturer of dental materials, for the past four years, together with having extensive share holding and stock options that she still had when her committee was making their decision. This would have at the very least resulted in a significant unethical conflict of interest.

New Zealand mouths full of amalgam

Many of the current middle-aged New Zealand population have an average of ten amalgam fillings. Indeed, a 1968 New Zealand Health Department investigation revealed that adults at 21 years had an average of 16 fillings with 15 year old ‘teenagers already having 13 at that time. This was due to the practice of “drilling and filling” or “prevention by extension” any tooth with a natural deep fissure or shallow surface erosion, or even “just for practice” as stated by a school dental nurse to a Tauranga mother 50 years ago who asked why her eight year old daughter had been given eight fillings despite, according to the nurse, having excellent teeth.

This changed quite dramatically in 1976 after a curious Health Department memo to all dental personnel effectively telling them to only drill into teeth showing actual decay. The number of fillings dropped by 30% within a year and by 60% within five years due to these “changes in dental practice” as stated in a subsequent New Zealand Dental journal paper.[9]

Amalgam and the increase of Alzheimer’s disease

Those young adults are now entering their senior years with a mouth full of corroding metals. We can therefore expect a senile dementia epidemic of unheard of proportions. This is not fanciful conjecture as the subject has been discussed at international meetings with some of the world’s leading toxicologists and scientists.

The State subsidy will cost NZ$500,000 per Alzheimer patient surviving ten years in a nursing home and, based on the literature,[6] there could well be 7-10,000 early onset cases, i.e. before the age of 70, and upwards of 100,000 if most of the one million post-war baby-boomers were to live into their 80s. The recently released New Zealand Alzheimer’s Society’s Report indeed supports this with over 40,000 known cases in 2008 and projected numbers increasing to 75,000 by 2026 and nearly 150,000 by 2050. The annual costs in 2008 already exceeded NZ$435 million with projections to exceed NZ$1billion p.a. in the near future. However, so far, it appears that only the Swedish MPs have had the foresight and political wisdom to take any appropriate action.

Mercury and cancer

Mercury has also been identified as a significant factor in cancer promotion in that it kills lymphocytes (white blood cells) in the blood, including the Natural Killer (NK) cells that identify and destroy cancers when active, i.e. alive.[10] Notably, it has been proven that there is both an increased risk of cancer spreading and a higher mortality when NK cells are inactive (or dead).[11,12] Further research is ongoing, but, notwithstanding the recent FDA and the New Zealand Health Select Committee’s denials, it would seem that dentistry needs to be seriously considered as a major covert cause of chronic illness.


Mike Godfrey, MBBS FACAM FACNEM, is medical director of the Bay of Plenty Environmental Health Clinic



  • In 2006, Whangarei doctor, Damian Wojcik, published his research on data from 456 patients who had been clinically tested for mercury poisoning. Mostly, the mercury source was identified as coming from amalgam fillings. NZPA Wellington, 13 May 2009. Dr Wojcik is a Trustee of Physicians and Scientists for Global Responsibility (PSGR) 

  • Sweden, Norway and Denmark have banned mercury amalgam fillings because of health and environmental concerns. The NZ Dominion Post, 5 September 2009. 

  • The phrase "mad as a hatter" originated from hat makers who went crazy using mercury in their trade. In Japan and Iraq, mercury poisoning has been documented from the use of a mercury-based fungicide in the 1970s. 


Check out:

 A petition calling on Government to ban mercury amalgam for children and pregnant women immediately, and phase out entirely by 2013, met with “a report issued by Parliament's health select committee” which “found there was no conclusive evidence to prove amalgam fillings caused health problems.”

Petition organizer, Juliet Pratt (, believes her nine years of chronic fatigue syndrome was caused by mercury leaking from amalgam fillings. Since replaced, “I've got back into sport. My life is totally changed." The Dominion Post, 5 September 2009.


Enquiries for Poisons in your mouth - fluoridation and amalgam by Mike Godfrey and Robert Anderson to


  1. World Health Organisation. Environmental Health Criteria 118(1991),74

  2. Richardson GM and Allan MA. Human Ecol. Risk Assess. 2(4) (1996), 799-761

  3. Cutress TW, Whyman RE, Godfrey ME, Miller J. Dental Amalgam and Human Health. NZ Ministry of Health Govt. Printers June(1997)

  4. Jones L. Acta Neuropsychiatrica.16 (3)(2004),142-146

  5. Material Safety Data Sheets (MSDS) and Directions for Use (DFU) Dentsply/Caulk and Ivoclar (Europe) at: http://caulk/MSDSDFU/DispersalloyMSDS Accessed Feb.1998

  6. Godfrey ME, Wojcik DP and Krone CA, J.Alz. Dis. 5(2003),189-195

  7. Lindh U, Hudecek R, Danersund A, Eriksson S, Lindvall A. Neuroendocrin Lett. 23(5-6)(2002),459-482

  8. Mutter J, Naumann J and Guethlin C. Crit. Rev. in Toxicol. 37(2007),537-549

  9. De Liefde B. NZ Dental J. 94(1998),109-113

10. Huggins HA. Explore 3(2)(2007),110-117

  1. Head J. et al. Ann. NY Acad. Sci.1993;690:340-2

  2. Imai K. et al. Lancet 356(9244)(2000),1794-99