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Mercury falling

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It’s finally looking like the beginning of the end for amalgam dental fillings as the EU looks set to impose a Europe-wide ban

It was controversial when dentists first started using mercury in amalgam fillings 160 years ago-but it has taken until now for a Europe-wide ban to be enforced at every dental practice in the 27 countries that form the European Union (EU).

The ban is expected to be agreed on in 2013, although it won’t fully apply until 2018,

by which time dentists will be legally required to use safer materials for fillings.

The ruling marks the beginning of the end for amalgam fillings, which are mainly made up of elemental mercury, one of the most toxic substances known to man. Although scores of scientific studies have demonstrated that mercury vapours from the fillings leak into the body and become deposited in tissues-especially in the kidneys-it is amalgam’s impact on the environment that has finally sealed its fate.

The European Commission’s BIO Intelligence Service (BIS) is recommending a total ban that will be fully implemented in six years’ time, and which will see the use of mercury almost entirely eliminated throughout the EU. Its use in the production of batteries will be phased out by 2020.

The BIS has presented some of the most damning evidence of its impact on health that has ever been collated in a public document, and concludes that dental amalgam “can cause allergies and may increase the risk of neurological diseases, kidney diseases, autism, auto-immune diseases and birth defects”. Pregnant women and children are especially prone to amalgam’s health threats.

Despite the levels of mercury in the fish we eat and in our environment, dental amalgam is “by far the main source” of our total mercury load, the report’s authors continue. This has been proven by autopsy reports that have discovered up to 12 times more mercury in the body tissues of people with dental amalgam (European Commission BIO Intelligence Service. Study on the Potential for Reducing Mercury Pollution from Dental Amalgam and Batteries: Final report, 11 July 2012).

Several individual EU member states have already taken the initiative. Sweden and Denmark introduced a blanket ban on the use of dental amalgam in 2008, while Austrian and German dentists don’t use it in children, pregnant women and people with kidney problems. Norway, although not an EU member state, also banned it in 2008.

Not here, not us

The BIS report is an embarrassment for the world’s major dental groups-and especially the British Dental Association (BDA) and the American Dental Association (ADA)-which have consistently maintained that amalgam fill-ings are safe and don’t pose any risk to our health.

Yet, over the years, their safety claims have shifted as one after another has been demonstrated to be false. Here are their main claims and the arguments against them.

CLAIM 1: Amalgam fillings ‘lock in’ the mercury

Amalgam or ‘silver’ fillings are 50-per-cent elemental mercury mixed with copper, tin and silver.

This mixture is supposed to stabilize the filling and ‘lock in’ the mercury. This was the view of both the BDA and ADA for more than a century until the introduction of sophisticated technology such as mass spectrophotometry in the late 1970s, which could detect mercury vapours being released by the amalgam fillings.

But even before the use of sensitive monitors, it was deduced that the fillings must be leaking because old amalgam fillings contained considerably less mercury than new ones (ZWR, 1970; 79: 1031-6). This was proven by a series of experiments with groups of people, with and without fillings, whose mouths were inspected before and after chewing. After 10 minutes’ chewing, the mercury concentration in the mouths of those with fillings was 10 times that of those without amalgam, and remained high for 90 minutes (J Trace Elem Exp Med, 1990; 3: 111-23).

Today, it is accepted that amalgam fillings release mercury vapours when we chew or grind our teeth, or have hot drinks, although the greatest amount of mercury is released when the filling is first inserted or removed.

CLAIM 2: Our bodies can tolerate the level of mercury from our fillings

It could be argued that there can’t be a ‘safe’ level of exposure to one of the world’s most toxic elements, although the US Environmental Protection Agency (EPA) reckons the body can tolerate 5.8 mcg (microgrammes) of mercury per one litre (L) of blood. This is mercury from all sources-the environment, the fish we eat and amalgam fillings. The EPA claims that fish consumption is by far the most significant source of mercury, but this is disputed by the World Health Organization (WHO), which reckons that we absorb four times the level of mercury from our fillings as from fish. On average, we absorb around 10 mcg of mercury from our fillings every day-obviously depending on the number of amalgam fillings we have-compared with 2.3 mcg from our diet and just 0.3 mcg from the environment (WHO International Programme on Chemical Safety. Environmental Health Criteria 118, Inorganic Mercury, 1991: 61).

So, a person with a dozen amalgam fillings is absorbing around 1.83 mcg of mercury a day (J Dent Res, 1987; 66: 1775-80), but this escalates to 27 mcg in someone with 47 ‘amalgam surfaces’, assuming some teeth have more than one filling (Arch Environ Health, 1994; 49: 384-94).

A separate analysis by Health Canada put the risk levels far lower than the EPA’s, and suggested that the maximum number of amalgam fillings should be zero to one in children up to the age of 11, one to three in adolescents up to the age of 19, and between two to four in adults. These numbers of amalgam fillings would release levels of mercury that the body could tolerate. Even so, the researchers concluded, “no clear threshold for subclinical neurological and cognitive function impairment is evident”-in other words, there are no safe levels when you have amalgam fillings (Hum Ecol Risk Assess, 1996; 2: 709-61).

This conservative view has been supported by the US Agency for Toxic Substances and Disease Registry, which has set a minimum risk level of mercury at just 0.14 mcg. At this level, even one amalgam filling is unsafe.

CLAIM 3: Only people who are sensitive to mercury might suffer any ill health

The dental associations say that amalgam fillings are safe other than in people who are allergic or sensitive to mercury. The BDA reckons only around 3 per cent of the population is mercury-sensitive, which still equates to 1.8 million people in the UK.

This estimate is not supported by the evidence, however. A skin patch test discovered that 8 per cent of the test group was mercury-sensitive (Arch Dermatol, 1973; 108: 537-40), while another found that double the number-16.1 per cent-of healthy people were sensitive (Int Dent J, 1969; 19: 481-8).

But the most sensitive seem to be dentists themselves: one study at Baylor College of Dentistry discovered that 32 per cent of the 171 students tested were sensitive. Their sensitivity or allergy increased with the number of amalgam fillings they had and the time they had been studying at the college (J Dent Res, 1985; 64: 338 [special issue, abstr #1472]).

Maths Berlin, professor emeritus of environmental medicine with the WHO, reckons that around 10 per cent of people with amalgam fillings will suffer some side-effect, presumably because they are sensitive to the mercury (The Dental Material Commission Final Report, 2002).

Easy come, easy go?

For the healthy, non-allergic person, the small amounts of mercury from fillings will simply pass through the body, maintain the dental associations. Urine samples from people who have recently had amalgam fillings appear to support the claim-but it’s not the whole story.

Berlin’s WHO study discovered that people with the most amalgam in their teeth-which was exposing them to 100 mcg of mercury every day-were excreting just half that amount in their urine (The Dental Material Commission Final Report, ibid.).

In fact, the body’s ability to excrete mercury appears to diminish over time. In a study of 507 children with amalgam fillings, mercury in their urine increased in the first two years after they had the fillings and then dropped off until, by year seven, levels were the same as in children who had no fillings.

This might suggest that mercury emissions from the fillings were also falling-except that the children had received amalgam replacements and restorations during years six and seven (JAMA, 2006; 295: 1784-92).

Mercury is deposited in the kidneys, which appears to affect their healthy functioning. Studies by Murray Vimy and his colleagues at the University of Calgary Medical School-who were among the earliest researchers into the effects of mercury-discovered that the metal impaired healthy kidney functioning when he examined six sheep that had been given amalgam fillings.

Although the kidneys became less efficient, Vimy’s team noted there was no physical change in the kidneys (Am J Phsyiol, 1991; 261: R1010-4).

Autopsy studies then also confirmed that the kidneys weren’t doing their job. Levels of mercury concentration in tissues and organs have been correlated with the number of fillings, and have been shown to affect the brain, the central nervous system, the pituitary glands and the kidneys.

In their sheep studies, Vimy’s group discovered high concentrations of mercury in the stomach, kidneys and liver, although every organ had some deposits of mercury (FASEB J, 1989; 3: 2641-6).

Women and children first

Even the BDA recommends that pregnant women should avoid having amalgam fillings, as mercury can pass through the placenta wall and affect the developing fetus. But its advice is a precaution and not an acknowledgement that the fillings can affect our health, it adds.

Again, however, the evidence suggests it is more than cautionary. Mercury from fillings in the mother have been discovered in the hair of fetuses and newborns (European Commission BIO Intelligence Service, op. cit.), and the American Academy of Pediatrics’ Committee on Environmental Health has stated that “the developing fetus and young children are thought to be disproportionately affected by mercury exposure . . . mercury in all its forms is toxic to the fetus and children, and efforts should be made to reduce exposure to the extent possible to pregnant women and children as well as the general population” (Pediatrics, 2001; 108: 197-205).

A smoking gun

The dental associations often fall back on the old medical homily of ‘the dose makes the poison’. In other words, the amount of mercury released by fillings is too little to have any adverse effect on our health.

Indeed, proving a direct causal link between amalgam fillings and neurological and auto-immune diseases is difficult, if not impossible, as so many factors are at play. However, the evidence that indirectly points to a link is particularly compelling.

We know there is no such thing as a ‘safe dose’ when it comes to mercury, and exposure to the metal-in any of its forms-can cause mercury poisoning, or ‘hydrargyria’. Such poisoning can damage the brain, kidneys and lungs, while symptoms include impairment to sight, hearing and speech, and muscle coordination.

Critics such as Professor Boyd Haley from the University of Kentucky suspect that amalgam fillings are responsible for a range of neurological problems, including autism in children and Alzheimer’s in the elderly. Haley and other researchers at the university have discovered that mercury is the most plentiful trace element found in the brains of Alzheimer’s victims.

The one chronic condition proven to be directly caused by amalgam fillings is periodontal, or gum, disease. Nine separate studies have demonstrated a direct link, as Murray Vimy has pointed out to the ADA, after it claimed there was no evidence

to suggest that fillings caused chronic disease.

“Periodontal disease is one of the most prevalent chronic diseases in man, and mercury fillings contribute significantly. The ADA and its advisors may

be knowingly misinforming the public through the media, or they lack the understanding of the scientific research about mercury release from amalgam published in their own journals,” he said (News release, University of Calgary, July 4, 2001).

There is a mass of anecdotal evidence about patients who have had their amalgam fillings removed and the health improvements they noticed afterwards (see box, page 12). Six separate studies, which questioned a total of 1,569 patients, discovered that very large numbers of them said a range of health problems had improved or been completely reversed, including chest pains, depression, fatigue, gastrointestinal problems, gum problems, migraine, multiple sclerosis, memory loss and irregular heart rhythms (Bio-Probe Newsletter, 1993; 9: 2).

A high cost

The early dentists refused to handle amalgam when it was first mooted as a more pliable, durable and less costly alternative to gold. One of the leading dentists at the time, Chapin Harris, described amalgam as “one of the most objectionable articles for filling teeth that can be employed”. Because of his resistance, America’s first dental association, the American Society of Dental Surgeons, which Harris co-founded, disbanded and was replaced by the amalgam-accepting American Dental Association in 1860.

To this day, cost remains one of the most compelling reasons for amalgam’s longevity. The UK government is staunchly opposed to the EU’s moves to replace amalgam with a safer alternative, such as composite resin, because it fears dental costs may double, which could be a mortal blow to an already overstretched National Health Service.

In addition, any admission that amalgam fillings are dangerous would inevitably trigger a panic rush to the dentist to have them replaced. And, in the litigious US, any acknowledgement of the health hazards of the fillings while allowing them to still be used could trigger lawsuits from patients with chronic health problems.

Perhaps the last word should go to Boyd Haley who, in a report to the International Academy of Oral Medicine & Toxicology (IAOMT), said: “It is a dereliction of duty to place a toxic material into any patient.”

It’s a conclusion that the EU has finally reached-and with which perhaps one day even our dental associations will agree.

Bryan Hubbard

Removing amalgam fillings safely

Having your amalgam fillings removed is hazardous and should be undertaken only by a dentist who is highly experienced in the correct procedure. Done badly, you will be exposed to very high levels of mercury.

Because of this, Maths Berlin, the World Health Organization’s professor emeritus in environmental medicine, recommends that only patients who have symptoms of possible mercury poisoning-such as fatigue, memory loss and heart problems-should have their amalgam fillings removed.

< span>The single most important aspect of the procedure-for you and the dentist-is that you are both fully protected against breathing in the mercury fumes released when drilling begins. Dentist Stephen Koral, who follows the recommendations of the International Academy of Oral Medicine & Toxicology, says that a high-volume suction device should be used throughout the procedure and, while a rubber dam is advisable, it’s not essential.

However, an experienced dentist will completely cover your face and you should be breathing piped-in air from a respirator.

Finally, the dentist may recommend that you take a chelating agent such as DMSA to help remove mercury from your tissues and organs.

Are you suffering from your amalgam fillings?

Amalgam fillings are suspected of causing neurological and autoimmune health problems, although a direct link has never been established. However, a group of 1,569 patients has reported on their health improvements after having had their fillings removed, and here are the results.


Percentage claiming substantial relief





Bad temper




Blood pressure problems


Chest pains








Gastrointestinal problems


Gum problems








Irregular heartbeat




Lack of concentration


Lack of energy


Memory loss


Metallic taste in mouth


Multiple sclerosis


Muscle tremor






Skin problems


Sore throat




Thyroid problems


Oral ulcers


Urinary tract problems


Vision problems


Source: Bio-Probe Newsletter, 1993; 9: 2

What’s the alternative?

Assuming that you need dental fillings, there are five different materials that could be used, including amalgam. Amalgam has remained the filling of choice because it’s inexpensive, pliable and durable, despite its potential negative impact on your health and on the environment.

Here are the options, their durability and annual rates of failure.



Failure rate


(% per year)

Resin-based composite resins



Polyacid-modified composites



Resin-modified glass ionomers



Glass ionomers






Source: World Health Organization. Future Use of Materials for Dental Restoration, 2009

The scandal of the CAT

The Children’s Amalgam Trial (CAT) was supposed to be the definitive word on whether mercury fillings cause neurological problems in children. The research team, from the University of Washington in Seattle, concluded that amalgam was safe to use in children-and that should have been the final word on the subject.

However, it’s turned out to be just the beginning even though the studies were published in 2006. The researchers have been accused of bad science-and worse, they have been reported to the International Criminal Court for ‘abusing’ the children by implanting amalgam fillings without first getting proper consent.

Certainly the researchers could have chosen better subjects.

They selected 500 children from the Casa Pia, a state-owned orphanage in Lisbon, Portugal, which had been the subject of a major sex scandal.

The children, who were in poor health, were given amalgam or composite resin fillings, and their health and development was monitored for seven years.

The researchers could find no difference between the two groups, as demonstrated by the findings of the first study (JAMA, 2006; 295: 1784-92).

However, other researchers found flaws in the way the study had been set up and how the children were monitored. Even an accompanying editorial by Herbert Needleman, of the Department of Psychiatry at the University of Pittsburgh School of Medicine, pointed out that “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” (JAMA, 2006; 295: 1835-6).

But the main criticism has come from scientists and dentists associated with the International Association of Oral Medicine & Toxicology, who say the researchers failed to use sensitive testing parameters to assess mercury levels. The following year, James Woods, one of the original research team, published a separate paper revealing that the boys in the study had suffered kidney damage and were unable to excrete mercury (Environ Health Perspect, 2007; 115: 1527-31).

It got worse for the researchers last June when the researchers were reported to the International Criminal Court in The Hague for ‘experimentally abusing’ the children. The accusation was made by DAMS (Dental Amalgam Mercury Solutions), a non-profit lobby group based in Saint Paul, MN, who claim the children were ‘enticed’ into the study and had amalgam fillings implanted without their proper consent.

October 2012 vol. 23.7

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