What toxicologists and medical researchers say about amalgam

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What toxicologists and medical researchers say about amalgam

http://home.online.no/~reiersol/friberg.htm

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A 1995 symposium report sums up the scientific controversy over amalgam in

this way:

The controversy concerning the safety of dental amalgam has intensified in

recent years. While proponents continue to reaffirm its safety by pointing

to the millions of dental cavities that are annually being filled with

amalgam without (apparently) causing any ill effects, opponents are

demanding the immediate ban of dental amalgam, citing studies which

demonstrate that substantial amounts of mercury from such fillings are

released and absorbed, causing mercury to accumulate in organs and tissues,

in pregnant women even in the fetus.

Although the health consequences of the accumulation of mercury in the

human body are not yet fully understood, mercury is receiving increasing

attention as an immunotoxic element and for this reason it is suspected to

play a role in the development of a variety of chronic diseases.

Proponents of amalgam consider these claims to be largely unproven. They

also point out that many of the symptoms attributed to chronic mercury

exposure from amalgam fillings are too non-specific to be relevant, and

they further argue that, in the absence of a suitable low-cost replacement,

a ban of amalgam would have serious practical and fiscal consequences.

However, in view of the mounting opposition against the use of amalgam,

dental professionals in many countries are increasingly revising their

previous positions and public officials are preparing regulations for the

restricted use and eventual ban of all amalgam-based dental materials. [1]

The following quotes are mostly from researchers who have contributed

significantly to current knowledge about the health risks of amalgam. All

of them are skeptical or negative to amalgam. There are many sources for

the opposite point of view, but the vast majority of them are from dental

organizations or researchers. These have done little relevant research of

their own, perhaps thinking that criticizing the work of others is

sufficient. One pro-amalgam source that is not dentistry-based is the 1994

report from an expert group appointed by the Swedish National Board of

Health and Welfare. I find this document strongly biased in its coverage of

the scientific literature.

Unfortunately, you must be able to read Swedish to form an independent

opinion on that, since only the summary has been translated into English.

Lars Friberg

Lars Friberg is the author of the 1991 WHO report on inorganic mercury and

has contributed to the standard texts on metal toxicology. In the

concluding remarks to the above-mentioned symposium, he says:

My own conclusion is that already in individuals with bruxism, which is

common in the population, exposure may well be compared with industrial

exposure that has given rise to effects. Furthermore, despite negative

results in epidemiological studies, the statistical power is not high

enough to exclude the occurrence of effects in a few percent of the

population at still lower exposure levels. As amalgam is used so widely

already, an effect in a few percent of the exposed population would mean

that very large population groups could be affected.

The evidence from experimental and human studies at higher exposure levels

clearly indicates that mercury from the toxicological point of view is an

unsuitable element to use in dentistry. It is my opinion that it is prudent

to conclude that mercury from dental amalgam is not safe to use for

everyone. [2]

Mats Berlin

Mats Berlin is also one of the “old guard” of metal toxicology. His

publications are quoted no less than 5 times in Casarett and Doull's

Toxicology. In a 1992 article, although he still supports the continued use

of amalgam, he adds:

Such a decision [to continue using amalgam] should not be accompanied by a

smoke screen in the form of a general statement that amalgam is safe, which

is an untruth that only demonstrates deficient knowledge of fundamental

principles of environmental medicine... [3]

Recent risk assessments

A risk assessment by G. Mark and Margaret Allan was recently

published in a peer-reviewed risk assessment journal [4]. The authors

calculate a Tolerable Daily Intake (TDI) for mercury vapor, and find that

it corresponds to two (2) or (4) fillings using either of two different

exposure calculations. They also compare the two models to exposure limits

from risk assessments by the ATSDR (Agency for Toxic Substances and Disease

Registry a branch of the US Public Health service) and the USEPA. This

works out to (0) mercury fillings for the USPHS Standard, nine (9) and

eleven (11) mercury fillings for the USEPA Standard. They conclude:

It is apparent, therefore, that there is uncertainty in what constitutes a

level of Hg vapor exposure that is acceptable, tolerable, or of minimal

risk. Subsequently, there is uncertainty in the precise number of

amalgam-filled teeth that can be considered acceptable, tolerable, or of

minimal risk. However, it is also apparent that the continued unconditional

and unlimited use of amalgam as a dental restorative material, the placing

of up to 25 amalgam fillings in one individual, is not supported by the

available risk information.

Lorscheider, Vimy and Summers

Three medical researchers, Lorscheider, Vimy and Summers, were asked by the

FASEB Journal to review recent scientific findings on amalgam. The FASEB

Journal is one of the world's most prestigious scientific publications.They

state that “research evidence does not support the notion of amalgam

safety”, and conclude:

The experimental evidence indicates that amalgam Hg has the potential to

induce cell or organ patophysiology. At the very least, the traditional

dental paradigm, that amalgam is a chemically stable tooth restorative

material and that the release of Hg [mercury] from this material is

insignificant, is without foundation. [5]

Return to amalgam page

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1) Friberg LT, Schrauzer GN. Preface. In: Friberg LT, Schrauzer GN. Status

Quo and perspectives of amalgam and other dental materials. International

symposium proceedings. G. Thieme Verlag Stuttgart, 1995.

2) Friberg LT. Concluding remarks. In: Friberg LT, Schrauzer GN. Status Quo

and perspectives of amalgam and other dental materials. International

symposium proceedings. G. Thieme Verlag Stuttgart, 1995: 134-136.

3) GM, Allan M: A Monte Carlo Assessment of Mercury Exposure and

Risks from Dental Amalgam. Human and Ecological Risk Assessment 1996; 2

(4): 709-761.

4) Berlin M: Är amalgam i tandfyllningar en hälsorisk? [is amalgam in

dental fillings hazardous to health?]. Lakartidningen 1992; 89 (37):

2918-23. [My translation from the Swedish]

5) Lorscheider F, Vimy MJ, Summers AO: Mercury exposure from " silver " tooth

fillings: emerging evidence questions a traditional dental paradigm. FASEB

Journal 1995; 9: 504-8 .

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Last updated: August 6, 1997

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© 1997 Dagfinn Reiersøl