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Regulation of Dental Amalgams

Statement of

David W. Feigal, M.D., M.P.H.
Center for Devices and Radiological Health
Food and Drug Administration
Department of Health and Human Services


the House Committee on Government Reform

November 14, 2002


Mr. Chairman and Members of the Committee, I am Dr. David Feigal, Director of the Center for Devices and Radiological Health (CDRH) at the Food and Drug Administration (FDA or the Agency). I appreciate your invitation and the opportunity to discuss the issue of dental amalgam safety. My remarks will address FDA’s regulatory policy as it relates to dental amalgam.


Let me begin with a brief overview of our regulatory authorities regarding medical devices and how we exercise them in the case of dental amalgam.

As defined by Federal law, the term “medical device” encompasses several thousand health products, from simple articles such as tongue depressors and heating pads, to cutting-edge and complex devices such as pacemakers, lasers and imaging technologies. Dental amalgam, as well as its components – dental mercury and the alloy with which the mercury is combined – are medical devices.

The Medical Device Amendments of 1976 to the Federal Food, Drug, and Cosmetic Act (the FD&C Act) gave FDA specific authority to regulate the safety and effectiveness of medical devices. The FD&C Act prescribes a variety of mechanisms to achieve this goal. These include classification of medical devices, establishment registration, Quality Systems Requirements for manufacturing, and controls over the market introduction of medical devices.

Devices on the market at the time the 1976 Amendments were passed were assigned to one of three “classes.” Devices posing the lowest risk, such as elastic bandages, were placed in Class I, subject to the “general controls” I just outlined. Class II devices, which pose incrementally greater risk and whose safety and effectiveness cannot be adequately controlled with Class I requirements, are subject to “special controls.” These range from post-market surveillance studies to conformance with mandatory performance standards. The riskiest devices, such as some implants and life-supporting or life-sustaining devices, are placed in Class III and undergo premarket evaluation, including clinical studies, before manufacturers can introduce them into commerce.

The FD&C Act also authorizes the Agency to “reclassify” a medical device to a higher or lower regulatory class as more knowledge emerges regarding product risk gained from actual use. In most cases, reclassifications result in de-regulation, or moving a device type to a lower class. Occasionally, though, new circumstances or information demonstrate that a device‘s risk profile has changed, warranting more rigorous regulation or placement in a higher regulatory class.


The Classification Process

Now let me address the specific issue of dental amalgam and the evolution of our regulatory position on this product, as well as how we presently regulate dental amalgam.

Dental amalgam is a restorative material used to treat dental caries. Amalgam has an extremely long history of use; oral health care providers have utilized amalgam for well over 100 years. Evidence accumulated over the years has consistently shown amalgam to have wide applications. Dental amalgam is easy to manipulate, has reasonable clinical serviceability, and is highly durable.

Dental amalgam consists of roughly equal parts of elemental mercury (43-54 percent) and an amalgam alloy made from other metals such as silver, tin and copper, sometimes with smaller amounts of zinc, palladium or indium present. Dental amalgam alloy, both in encapsulated and free-standing form, are pre-Amendment devices. Historically, dental mercury has been regulated as a Class I device. The alloy has been regulated as a Class II product because of potential risks that could result from variations in chemical formulation related to percent composition and types of materials. The encapsulated form of amalgam, which consists of measured proportions of amalgam alloy and dental mercury that are separately sealed and sold as a single-use capsule, was never classified during the original classification process. However, because it is a combination of two classified devices, the encapsulated form is regulated in Class II given that one of its components, the alloy, is a pre-Amendments Class II device.

Early Concerns About Safety

In the early 1990s, FDA became increasingly aware of consumer concerns about the mercury component of dental amalgam and whether certain, and in many cases, non-specific health problems were attributable to mercury exposure.

At the direction of the Assistant Secretary for Health, the National Institutes of Health (NIH), the Centers for Disease Control and Prevention (CDC) and FDA (as members of the Committee to Coordinate Environmental Health and Related Programs) conducted a comprehensive review of both the health risks and clinical effectiveness of the product.

This extensive evaluation demonstrated that clinical benefits of dental amalgam outweighed observable risks, including mild, transient allergic reactions among a very small percentage of the patient population. In 1993, the Public Health Service (PHS) issued a comprehensive risk management plan that had been developed with outside peer review. Its purpose was to ensure that NIH, CDC and FDA collaborated to advance the state of science, to keep dental personnel current on the latest scientific information about amalgam safety, and to maintain an appropriate level of regulatory control over the product.

It is important, Mr. Chairman, to emphasize the 1993 Public Health Service report’s science-based conclusions that there was no definitive evidence linking the placement of amalgams and the onset of systemic disease. These conclusions have not changed in the intervening nine years. PHS experts conducted follow-up reviews in 1995 and again in 1997. Also in 1997, FDA toxicology experts and other experts from outside FDA performed an extensive review on more than 170 scientific studies that consumer advocacy and other concerned groups submitted at our invitation. Taken together, these reviews did not provide a basis on which to alter our risk management approach. These ongoing efforts have occurred at the same time the NIH has been actively pursuing a highly-focused agenda of clinical and non-clinical research in this area.

In addition to keeping abreast of the science here in the United States, we and our PHS colleagues have aggressively pursued information from public health agencies and organizations around the world in order to advance our scientific understanding.

To date, as I said, scientific opinion has remained constant and has validated and reaffirmed the 1993 findings of the Public Health Service. We are planning another review in conjunction with NIH and CDC to ensure the scientific underpinning of our regulatory policies remains current. Once again, this latest effort will involve experts from both the government sector and the external scientific community.


There has been some confusion about the regulatory status of dental amalgam and the purpose of a rule that the Agency proposed last February. As I explained earlier, mercury, alloy, and encapsulated amalgam are all legally marketed products. Since 1976 and at this time, mercury is a Class I device, alloy is a Class II device, and the encapsulated combination is unclassified but regulated as a Class II device.

In February 2002, our Agency proposed a rule to bring all amalgam products into Class II and increase the Agency’s regulatory oversight by requiring ingredient labeling and proposing conformance to international standards. By requiring disclosure of amalgam ingredients, the rule would help dental providers to quickly diagnose and treat rare allergic reactions arising from exposure to amalgam components. Given the high level of interest in this proposed rule, we twice reopened the comment period. We are now in the process of analyzing the more than 750 comments submitted to the docket.


Mr. Chairman, I want to reiterate that FDA is committed to monitoring closely the body of scientific evidence relating to dental amalgam safety in which NIH and others are now engaged. We will continue to exercise our regulatory responsibilities appropriately in accordance with the best available science. Finally, we will continue to work with the public health community on approaches to reduce the incidence of dental caries and optimize the quality of oral health care.

Thank you again for this opportunity. I would be pleased to respond to any questions Members of the Committee may have.