Recommendations About the Use of Dental Amalgam in
Certain High-Risk Populations: FDA Safety Communication
Date Issued: September 24, 2020
The U.S. Food and Drug Administration (FDA) is providing recommendations about the use of
dental amalgam (/medical-devices/dental-devices/dental-amalgam) in certain groups of
people who may be at greater risk to the potential adverse health effects of mercury exposure,
to include:
• Pregnant women and their developing fetuses;
• Women who are planning to become pregnant;
• Nursing women and their newborns and infants;
• Children, especially those younger than six years of age;
• People with pre-existing neurological disease;
• People with impaired kidney function; and
• People with known heightened sensitivity (allergy) to mercury or other components of
dental amalgam.
For over 20 years, the FDA has been reviewing, considering and holding public discussions
regarding the scientific literature and other evidence on the safety of dental amalgam. Key
among our findings are the uncertainties about the acceptable reference exposure levels for
mercury vapor (gas), the potential for mercury to convert to other mercury compounds in the
body, and whether the degree of accumulation of mercury from dental amalgam results in
negative (adverse) health outcomes. The FDA held a meeting of our Dental Products Panel of
the Medical Devices Advisory Committee in December 2010 (https://wayback.archiveit.
org/7993/20170403223455/https:/www.fda.gov/AdvisoryCommittees/CommitteesMeetingMaterials
/MedicalDevices/MedicalDevicesAdvisoryCommittee/
(http://www.fda.gov/about-fda/website-policies/website-disclaimer)
and a meeting of our
Immunology Devices Panel in November 2019 (/advisory-committees/advisory-committeecalendar/
november-13-14-2019-immunology-devices-panel-medical-devices-advisorycommittee-
meeting-announcement) to discuss these uncertainties. Elemental mercury used in
dental amalgam is known to cause adverse health effects, particularly when the extent of
exposure is high, in individuals who have reduced ability to remove mercury from their bodies,
and in individuals who are sensitive to mercury. Although the majority of evidence suggests
exposure to mercury from dental amalgam does not lead to negative health effects in the
general population, little to no information is known about the effect this exposure may have
on members of the specific groups listed above who may be at greater risk to potential negative
health effects of mercury exposure. Accordingly, the FDA recommends that non-mercury
restorations (/medical-devices/dental-amalgam/alternatives-dental-amalgam) (fillings) such
as composite resins and glass ionomer cements be used, when possible and appropriate, in
people who may be at higher risk for adverse health effects from mercury exposure.
The FDA does not recommend anyone remove or replace existing amalgam fillings in good
condition unless it is considered medically necessary by a health care professional (for
example, a documented hypersensitivity to the amalgam material). Removing intact amalgam
fillings may result in a temporary increase in exposure of mercury vapor released during the
removal process in addition to the potential loss of healthy tooth structure.
At this time, the FDA does not find the available evidence supports a complete ban of the use of
dental amalgam (https://beta.regulations.gov/document/FDA-2008-N-0163-0250). The
weight of the existing evidence does not show that exposure to mercury from dental amalgam
leads to adverse health effects in the general population, and its longevity is better than that of
alternatives, especially for large restorations. In addition, a ban on amalgam may result in
deferred or no treatment and have unintended health implications,especially in communities
where there might be limited availability of alternative materials.
Recommendations for Patients and Caregivers About the Use of
Dental Amalgam
• Be aware the following groups of people may be at greater risk for potential negative
effects of mercury vapor (gas) released from dental amalgam fillings:
◦ Pregnant women and their developing fetuses;
◦ Women who are planning to become pregnant;
◦ Nursing women and their newborns and infants;
◦ Children, especially those younger than six years of age;
◦ People with pre-existing neurological disease;
◦ People with impaired kidney function;
◦ People with known heightened sensitivity (allergy) to mercury or other components
of dental amalgam.
If you are an individual in one of these groups, the FDA recommends that alternative, nonmercury
materials such as composite resins or glass ionomer cements be used when possible
and appropriate.
• Be aware the durability of any tooth restoration (filling) depends on many factors besides
dental filling material. To help your teeth and fillings last as long as possible, you should
maintain a healthy diet, proper oral hygiene, and regular dental checkups.
• You should discuss treatment options, including the associated benefits and risks of
using detal amalgam or an alternative non-mercury filling material, with your dentist.
View the FDA’s informational brochure (/media/142415/download) for patients and talk
with your dentist if you have additional questions.
Recommendations for Dental Health Care Providers About the Use of
Dental Amalgam
• Review the above Recommendations for Patients and Caregivers About the Use
of Dental Amalgam and discuss the risks and benefits of using dental amalgam and
other restorative materials with your patients to allow them to make informed choices
regarding their treatment options. We encourage you to share the FDA’s informational
brochure with your patients prior to any consent to treatment.
• When discussing dental amalgam, avoid using the term "silver filling," as this may imply
the filling is made solely from silver and does not accurately convey the mercury
component of this restorative material.
• When using amalgam:
◦ Use encapsulated amalgam and avoid bulk elemental mercury to minimize the risk
of occupational exposure.
◦ Avoid placing amalgam in direct contact with other fixed or removable metallic
devices in the mouth.
◦ Use mercury hygiene best practices
(https://www.ada.org/~/media/ADA/Member%
20Center/Files/topics_amalgamwaste_brochure.ashxx)
(http://www.fda.gov/about-fda/website-policies/website-disclaimer) to minimize
the patient’s and your exposure to mercury vapor. Use amalgam separators
(https://www.epa.gov/eg/dental-effluent-guidelines) to prevent mercurycontaining
dental amalgam waste from being released into the environment.
Potential Adverse Health Effects of Mercury Exposure from Dental
Amalgam
Dental amalgam (/medical-devices/dental-devices/dental-amalgam) is a type of dental
restorative material that is a mixture of elemental mercury and an alloy primarily composed of
silver, tin, and copper, and is used to restore the missing structure and surfaces of a decayed
tooth. It releases small amounts of mercury in the form of a vapor (gas), depending on the
number and age of existing fillings as well as some dietary and chewing habits. Inhaling
mercury vapors may be harmful, especially at doses considered higher than those typically
seen from use of dental amalgam. Mercury vapor release is highest when placement or removal
of the filling occurs. The levels of mercury vapors may also temporarily increase when chewing,
brushing, or teeth grinding over the tooth with the amalgam filling. The mercury vapors are
primarily absorbed by the body through inhalation to the lungs. The body eliminates some of
the absorbed mercury, but small amounts distributed through the bloodstream may collect in
certain tissues, including the brain and kidneys, or in the case of pregnant women, in the blood
going to the fetus through the umbilical cord.
Mercury is a known toxicant to the nervous system and long-term exposure to high mercury
doses, such as may occur in some occupational settings, may be associated with signs or
symptoms (https://www.atsdr.cdc.gov/sites/toxzine/mercury_toxzine.html) such as:
• Mood disorders (for example, anxiety, depression, irritability)
• Sleep difficulties or disturbances
• Fatigue (feeling tired)
• Memory troubles or disturbances
• Tremors (shaking of extremities)
• Difficulties with coordination
• Visual changes
• Changes in hearing
• Kidney damage
The concentrations of mercury vapor released from dental amalgam are low compared to those
typically associated with clinical signs of toxicity. Over more than two decades, the FDA and
other public health agencies have conducted numerous reviews of scientific data related to
potential health effects of dental amalgam. These reviews have generally arrived at the same
conclusion that the weight of the existing evidence does not show that exposure to mercury
from dental amalgam leads to adverse health effects in the general population, including those
signs and symptoms listed above as well as some neurodegenerative diseases such as multiple
sclerosis, Alzheimer’s disease, and Parkinson’s disease.
Although the weight of available evidence does not show that exposure to mercury from dental
amalgam leads to adverse health effects in the general population, some caution should be
exercised when interpreting conclusions made from review of the scientific literature for
reasons including, but not limited to, the following:
• Conflicting or contradictory findings from different studies that may have affected the
certainty in reaching the determination on dental amalgam exposure.
• Exposure to additional amounts of mercury from other environmental and/or dietary
sources (such as fish) and recent evidence regarding the body’s ability to convert one
form of mercury into another, which have raised uncertainties regarding the attribution
of mercury exposure sources in a given individual.
• Limitations in study design and execution, including lack of control groups, small sample
sizes, single-source data, limited duration of follow-up, and underpowering for
evaluation of less common outcomes.
There are also uncertainties regarding the levels of exposure to mercury vapor from dental
amalgam, and what level of exposure is considered safe for greater risk individuals. Levels of
exposure do not necessarily fall consistently within a narrow range, but are dependent on size,
number, and age of the fillings, and stresses applied to the filling, such as chewing and
brushing. Current estimates of continuous, exposure to mercury from dental amalgam and
other sources over a lifetime that are likely to be without risks of harmful effects in the general
population and greater risk groups, vary considerably. Taken together, these uncertainties
present challenges with regard to defining a specific threshold of toxicity for chronic, low-level
mercury exposure from dental amalgam and other sources, particularly for sensitive groups.
There is limited data regarding health outcomes in groups of patients who may be more
susceptible or sensitive to the direct neurological effects of mercury (such as developing fetuses
and children, and individuals with neurological disorders), or those with an impaired ability to
excrete mercury (such as those with kidney dysfunction). Therefore, there is greater
uncertainty and concern about the potential risks to these individuals.
Use of Amalgam versus Resin-Based Composites
Dental amalgam has advantages over resin-based composites in certain limited clinical
situations. This includes use in high caries risk patients, for large fillings in posterior (back)
teeth where biting forces are high, and where moisture can present a problem for certain
placement such as near the gumline. For esthetic reasons and others concerning mercury use
and disposal, the use of dental amalgam has seen a significant decline over the last decade.
Other filling materials (/medical-devices/dental-amalgam/alternatives-dental-amalgam) such
as resin-based composites and glass ionomers have become more widely used. The durability
of these resin-based materials has improved, although its longevity does not equal that of
amalgam, especially for large restorations with higher biting forces, wear, or stress.
Resin-based composite materials (/medical-devices/dental-amalgam/alternatives-dentalamalgam)
have important advantages. Namely, they are color-matched to the surrounding
tooth structure for better esthetics and do not contain heavy metals, and their placement
typically requires the removal of less healthy tooth structure compared to dental amalgam.
Resin-based materials disadvantages include shrinkage that can lead to marginal gaps,
hypersensitivity to unreacted methacrylate components as well as clinical limitations regarding
placement and longevity. Resin-based composites also generally require more time and cost for
placement.
If a patient is concerned about mercury exposure from dental amalgam or falls into one of the
high risk populations listed above, the use of alternative materials should be strongly
considered.
FDA Actions
The FDA will continue to keep the public informed if significant new information about dental
amalgam becomes available.
Additional Resources
• FDA’s Dental Amalgam Website (/medical-devices/dental-devices/dental-amalgam)
• FDA’s Informational Brochure - Information for Patients About Dental Amalgam Fillings
(/media/142415/download)
Reporting Problems with Your Dental Amalgam
If you think you have had an allergic or other reaction attributable to dental amalgam, the FDA
encourages you to report the problem through the MedWatch Voluntary Reporting Form
(https://www.accessdata.fda.gov/scripts/medwatch/index.cfm?action=reporting.home).
When submitting a report, detailed information regarding the signs and symptoms of the
adverse event and the timing of the events relative to the placement of the material would be
useful to FDA’s evaluation.
Health care personnel employed by facilities that are subject to the FDA's user facility
reporting requirements should follow the reporting procedures established by their facilities.
Questions?
If you have questions, email the Division of Industry and Consumer Education (DICE)
at DICE@FDA.HHS.GOV (mailto:DICE@FDA.HHS.GOV) or call 800-638-2041 or 301-796-
7100.
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