Tooth filling materials Dental amalgams & alternative materials
7. What is the environmental risk of the use of dental amalgams and alternative materials?
- 7.1 Does mercury released by the use of amalgams pose a risk to the environment ?
- 7.2 What is the environmental impact of alternative tooth filling materials?
7.1 Does mercury released by the use of amalgams pose a risk to the environment ?
Methylmercury can accumulate along the food chain ©
Mercury occurs naturally
in the environment in different chemical forms.
is the form used in dental
amalgams. Forms more commonly found in nature are
and organic mercury.
Most of the mercury in
the environment comes from natural sources such as emissions
from volcanoes and soil erosion. However, over the last several
centuries the levels of mercury in the environment have
increased because of human activity. The widespread use of
mercury and its compounds
in a number of industries has resulted in larger releases of
mercury into the atmosphere. Mercury is present in many
cosmetics, medicinal products and medical devices including
Moreover, some mercury compounds – especially the
have accumulated in the aquatic
dental amalgam can
end up in the soil, atmosphere, surface water and ground water
through several routes, including wastewater discharges from
dental practices, and emissions to air and soil resulting from
the cremation or burial of individuals with dental
The amount and the type of
mercury released from
dental clinics vary widely across the EU depending on levels of
usage of dental amalgam and
on how the wastewater is treated before it is discharged.
Wastewater released by dental clinics could increase the
in water bodies. The added risk for aquatic organisms
is considered low.
Sludge from plants that treat such wastewater present a low
risk for soil-dwelling organisms.
The main concern with emissions to water is related to the
well-known potential of
– an organic form of
mercury – to
bioaccumulate (build up
inside an organism) and biomagnify (build up along the
food chain). All
forms of mercury can
organisms, but methylmercury is taken up at a faster rate than
other forms and bioaccumulates to a greater extent. As a result,
methylmercury can become increasingly concentrated in aquatic
organisms and result in high levels of exposure for fish-eating
animals and for humans. Some of the
present in wastewater from dental clinics, for instance, will be
converted into methylmercury before its release (up to 0.2% of
the total mercury) but also once it reaches the environment. How
quickly this conversion takes place depends on the
characteristics of the ecosystem and is highly variable. Though
estimates are available of the amounts of mercury released by
the use and disposal of dental
amalgams in the European Union, it is not possible to
say what proportion of the risk associated with
present in the environment is due to releases from
At present it is not possible to do a complete
risk assessment to
human health and the environment of the use of
dental amalgam. In
general, the added risk to aquatic and soil organisms from the
contributions of dental mercury to the total mercury is
considered to be low. Improvements in the treatment of waste
water from dental clinics and
amalgam waste has
generally reduced this environmental exposure. Further studies
are needed to assess the environmental effects of burial and
cremation of bodies containing amalgam on soils.
7.2 What is the environmental impact of alternative tooth filling materials?
Some of the small organic
molecules (monomers) that are used to make the resin base for
alternative tooth filling materials are derived from well known
chemicals – notably methacrylic acids and glycidyl ethers.
Therefore, although data on the
toxic effects of these
new materials on animals and on the environment are not
available, major effects can be extrapolated. For instance,
exposures to high levels of a particular type of resin base are
expected to cause skin irritation and, if inhaled, are likely to
harm the liver and the nervous
The available information is too limited to assess the
relative effects of dental
amalgams and their alternatives on the environment.
To assess the full environmental impact it would be necessary
not only to determine the risk of environmental contamination
and its harmful effects on environmental organisms, but also
other environmental effects.