general practitioners continue to place amalgam
restorations, and think amalgam is safe and poses no
health risk to patients. They are, however, responding to
widespread patient concerns and inquiries, according to
recent survey results.
Originally published in the December 2002 Dental Products
four in five general practitioners in the United States
place amalgam restorations, according to the results of a
September DPR survey.l That said, more than two-thirds of
these dentists said they have decreased their use of
amalgam during their careers (see "Amalgam use"
chart). A nationwide survey by the ADA Health Policy
Resources Center showed that the number of amalgam
restorations placed dropped 28% from 1990 to 1999, while
the number of composite restorations placed jumped nearly
80% during the same time period.
reasons for this drop-off, and for a fifth of U.S. GPs
having discontinued the use of amalgam altogether, are
varied. By far, however, the most overwhelming motivation
for the shift away from amalgam is esthetics—more than
nine in 10 survey respondents cited patient preference for
esthetic materials as a reason for decreasing or stopping
amalgam use. An upcoming issue of Dental Products Report
will feature an in-depth look at the profession's opinions
on the amalgam controversy, examining specific issues such
as mercury toxicity, waste disposal concerns, and where
dentists are getting their information. The survey results
highlighted here focus on amalgam usage patterns and
bears repeating—79% of the GPs who responded to our
current survey said they offer amalgam restorations in
their practices. In fact, just over one-quarter (27%) of
these practitioners said that amalgam is used in more than
half of the direct restorations they place (see
"Amalgam caseload" chart, below). Interestingly,
the next largest single group of respondents (21%) said
that less than 10% of the direct restorations they place
are amalgam. So while amalgam is still used in many
practices, it is being used with less frequency in
Warsow, product manager for Kerr Dental's line of amalgam
alloys, offered a simple explanation. "The decline in
amalgam use is directly related to the rise in
composites," he noted. The survey responses bear this
out; 92% of those who said they stopped using or decreased
their use of amalgam indicated doing so because
"patients prefer composite resin for esthetic
pros (and con)
statement also implies that, other than esthetics, there
is nothing inherently wrong with amalgam as a restorative
material. Again, our survey results show that doctors
agree. Amalgam is touted most highly for its durability
and more than four in five survey respondents gave amalgam
an "Excellent" or "Very Good" rating
in this category (see "Rating amalgam" chart
below). Interestingly, the category that received the next
highest rating from respondents was biocompatibility,
relating to the very issue that naysayers are criticizing.
The only category in which amalgam did not score highly
was esthetics, which 91% of the respondents described as
the survey respondents appear to be resolute in their
support of amalgam safety, patient concerns are more
prevalent. More than three-quarters of the responding GPs
said one or more of their patients had asked to have
functional amalgams removed for safety reasons (see
"Requests to remove amalgam" chart below).
nearly all (98%) of the respondents said that they had
patients, albeit a small number, who had expressed concern
over the safety of mercury in their mouths (see Are
patients concerned? chart below).
basic formulation of amalgam has remained unchanged for
decades. "Silver, tin, copper, and mercury,"
Warsow said. "It's been the same for years, with
slight variations in the different percentages of these
why hasn't a suitable replacement been found for the
not for lack of trying, because there has been a lot of
research done," Warsow said. "But there is no
known substitute for mercury that we have found. The one
non-mercury alloy that actually came to market expanded so
much that it fractured teeth."
then, can't the amount of mercury be reduced?
certain ratio of mercury to the rest of the mix is
necessary to ensure the proper expansion rate and marginal
seal as well as to impart a plastic, workable
consistency," Warsow said.
bulk of dental amalgam research and development efforts,
Warsow noted, has had nothing to do with trying to reduce
the mercury content. "Most of the science has been
focused on changing the ratio of silver, tin, and copper,
as well as adding other metals, such as palladium, to
improve polishability and create a material with optimal,
of its history, we believe amalgam is safe," Warsow
said. "Toxicity testing is a very exact science. If a
product is expected to cause some type of health problem,
is it tested to rigorous standards prior to 510K approval.
There has never been any scientific evidence to show that
mercury-containing dental amalgam has caused any ill
effects in patients."
from these survey results, apparently most dentists agree. nDPR