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.
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 patient viewpoints.
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 individual practices.
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
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, controlled expansion."
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
Originally published in the December 2002 Dental