October 24, 2011 -- A World Health Organization (WHO) committee this month
called for a worldwide reduction in the use of dental amalgam to cut the flow of
mercury into the natural environment.
"In an environmental perspective, it is desirable that the use of dental
amalgam is reduced," Poul Erik Petersen, DDS, DrOdontSci, responsible officer of
the Global Oral Health Programme, told Medscape Medical News.
Dr. Petersen chaired a 2-day conference on amalgam as part of a United
Nations effort to organize a worldwide treaty on mercury. The WHO released a report
of the proceedings on October 11.
At a meeting in Geneva, Switzerland, from November 16 to 17, 2009, 29
experts from 15 countries concluded that the use of dental amalgam results in
180 to 240 metric tons of mercury being discharged into the atmosphere, soil,
and water every year. In contrast, 80 to 100 metric tons are recycled,
sequestered, or disposed of securely, the report said. However, the report
concludes, amalgam should not be banned outright because alternative filling
materials are more expensive and not as reliable.
The report calls for research to improve filling materials and said the use
of all dental filling materials should be reduced through measures that prevent
The report drew praise from an antimercury activist group, World Alliance
for Mercury-Free Dentistry, which released a statement calling the report a
"road map for the end of amalgam."
However, a spokesman for the American Dental Association said it is not
necessary to reduce the use of dental amalgam at all. "There is no reason per se
to phase down amalgam," Rodway Mackert, DMD, PhD, a professor of dentistry at
Georgia Health Sciences University in Augusta, told Medscape Medical
News. "The effect of doing that on the amount of mercury going into the
environment is negligible."
Dental caries are becoming an increasing problem in middle- and low-income
countries as they adopt Western lifestyles, including high consumption of
sugars, but have not yet begun widespread preventive programs, such as
fluoridation, the report says. As a result, the need for filling materials is
expected to grow in these countries.
Already, dental amalgam is releasing "a significant amount" of mercury into
the environment, the report found. This pollution results from amalgam made for
dental use but diverted to other purposes, from poor disposal practices, and
from cremation, the report said.
It laid out "best management practices," including bulk mercury collection,
chair-side traps, amalgam separators, vacuum collection, recycling, and
commercial waste disposal to prevent mercury from being released into the
environment. It cited a US Environmental Protection Agency estimate that 3.7
tons of mercury are discharged into the environment from US dental practices
Dr. Mackert said this is trivial compared with the 1500 tons generated by
mining and other industrial uses in the United States, and he cited an US
Environmental Protection Agency report saying that human activity only accounts
for a third of the total mercury released into the environment. "Most of the
mercury in tuna and things like that comes from natural sources like undersea
volcanic vents," he said. "Reducing man-generated mercury is so much
He said the American Dental Association supports best management practices
because if mercury gets into sewage sludge, then waste management companies
cannot sell the sludge. However, amalgam has clear advantages over other
restorative materials, so it should remain available to US dentists, Dr. Mackert
The WHO report considered the merits of amalgam vs other restorative
materials. It cites a study finding that the repair rate for composite resin
restorations was 7 times greater than for amalgams in posterior primary and
On the hotly contested issue of toxic effects from amalgam, the report
quoted a study by the Norwegian Dental Biomaterials Adverse Reaction Unit,
finding that "the majority of side-effects of dental filling materials are
linked with dental amalgam." Most of these are skin reactions and pain occurring
within a week after treatment.
The report noted that amalgam surfaces release mercury vapor into the mouth
and lungs, but stopped short of attributing any health effects to this
phenomenon, and pointed out that other restorative materials may also cause
So far, only Norway has completely banned amalgam, but some other
Scandinavian countries have policies for reducing its use. The report noted that
wealthy countries are better able to avoid amalgam because they have been able
to institute caries prevention programs, and because patients can afford more
Less-wealthy countries and indigent people living inside wealthy countries
should not be deprived of access to amalgam restorations until better
alternatives emerge, the report concludes.
Dr. Mackert has served as an expert witness for dental supply companies
sued for producing amalgam. Dr. Petersen has disclosed no relevant financial
World Health Organization. Future Use of Materials for Dental
Restoration: Report of the meeting convened at WHO HQ, Geneva, Switzerland 16th
to 17th November 2009
. Released October 11, 2011. Full text
Authors and Disclosures
Laird Harrison is a freelance writer for Medscape.
has disclosed no relevant financial