Dental amalgam, commonly known as “mercury fillings,” is a restorative material whose use is steadily decreasing worldwide. This material has been a mainstay of dentistry for well over a century and is now subject to significant international regulation. The shift away from amalgam is driven by environmental concerns over mercury pollution and the development of superior alternative materials. Its complete global phase-out is a process that is still underway.
Dental Amalgam: Composition and Historical Use
Dental amalgam is a mixture created by combining liquid elemental mercury with a powdered alloy, primarily silver, tin, and copper. Mercury acts as a binder, causing the metallic powder to form a plastic-like substance that can be pressed into a prepared tooth cavity before it hardens into a durable restoration. This composition provides a material that is highly resistant to wear and can withstand the forces of chewing.
The use of a mercury-based alloy for dental restoration has a long history, with records suggesting its application in China as early as 659 AD. Modern amalgam became widespread in the Western world in the 19th century, quickly becoming the standard restorative material. Its popularity stemmed from its low cost, ease of application, and exceptional longevity. For over 150 years, this combination of metals was the primary choice for treating tooth decay globally.
Key Regulatory Actions and Phase-Down Milestones
The global movement to restrict dental amalgam gained significant momentum with the Minamata Convention on Mercury, an international treaty adopted in 2013. This agreement required participating nations to “phasedown” amalgam use rather than imposing an immediate ban. A major milestone was the adoption of measures to exclude or recommend against amalgam use in vulnerable populations, specifically children under 15, pregnant women, and breastfeeding women.
Building on these efforts, the European Union restricted amalgam use for vulnerable groups starting in July 2018. This regional action accelerated the transition to mercury-free alternatives. The Conference of the Parties to the Minamata Convention agreed in November 2025 to a global phase-out date. This mandates that the manufacture, import, and export of dental amalgam cease by 2034. The European Union finalized a comprehensive ban on amalgam use for all patients, effective January 1, 2025, with limited exceptions.
Modern Dental Practices and Amalgam Alternatives
The decline in amalgam use is supported by alternative materials that offer improved aesthetics and functional benefits. The most common alternative is the resin-based composite, often referred to as a “tooth-colored filling,” which is an acrylic resin matrix reinforced with powdered glass filler. Composites are preferred because they can be matched precisely to the natural tooth color, making them nearly invisible. These materials are also bonded directly to the tooth structure, which helps to strengthen the remaining tooth.
Another alternative is glass ionomer cement, a material made from organic acids and fine glass powder. An advantage of glass ionomers is their ability to release fluoride, which helps prevent recurrent decay around the filling. While less durable than composites, glass ionomer cements are also less sensitive to moisture during placement. The development of these modern materials allows dentists to perform minimally invasive procedures that preserve more of the natural tooth structure.
Environmental Impact and Waste Management
A major driving force behind the phase-down of amalgam is its environmental impact through mercury pollution. Dental offices have historically been the single largest source of mercury discharge into municipal wastewater systems. This occurs when waste amalgam, such as excess material or fragments from the removal of old fillings, is washed down the drain.
Once in the wastewater, the mercury settles into the sludge at treatment plants, potentially entering the environment through land application or incineration. To mitigate this pollution, the U.S. Environmental Protection Agency (EPA) enacted a rule, codified as 40 CFR Part 441, in 2017. This regulation mandates that nearly all dental offices discharging to a public sewer system must install and maintain an amalgam separator. This device is designed to capture more than 95% of the mercury waste before it enters the drain. The compliance deadline for existing dental practices was July 14, 2020.