Since the beginning of January, amalgam has been effectively banned as a material for dental fillings in Luxembourg. A dentist explains why the ban was introduced, the consequences of the ban and what happens to existing amalgam fillings.
If you had cavities in the 1980s or earlier, you may still remember metal amalgam fillings as the standard material. Used for decades, its use has declined significantly in recent years.
“The advantages of amalgam are its ease of use, durability, cost and durability,” said Marlène Becker-Dubois, a dentist from Luxembourg. “Its disadvantages are its toxicity and its unattractive gray color.”
The ban, which began in January, is based on the revised EU mercury regulation, which restricts the use of mercury for environmental reasons and regulates the production and export of dental amalgam from the EU.
In 2023 alone, 40 tonnes of mercury were still being used annually for amalgam across the EU. This dental filling material is an alloy of various metals, including mercury – a powerful neurotoxin that can damage the brain, nervous system and other organs. However, in its bonded form as a dental sealant, it is considered stable and trouble-free. However, during its processing – such as its import or removal – a small amount of mercury vapor may be present.
The end after 150 years
Amalgam has been used as a dental filling material in dentistry for over 150 years. It’s known for its longevity and strength, and it’s relatively inexpensive—making it one of the most common choices for long-term dental fillings, especially for molars that must withstand intense chewing forces.
The ban is unlikely to make any significant difference to everyday practice, as alternative materials have been used for many years. Even before the ban, amalgam was already banned for use in people under 15, pregnant women and nursing mothers. Instead, dentists increasingly rely on modern materials such as ceramics, reinforced plastics or glass ionomer cement.
The new fillings are more complex
These new materials, known as composite materials, are more aesthetic and environmentally friendly, but on the other hand they are more complicated to process. They are connected to the dental substance with an adhesion technique. The surface must be dry and clean to ensure a strong and firm adhesion.
“Amalgam is an expanding material, while composites shrink slightly during the polymerization process,” Becker-Dubois explained. “Amalgam is held in place by its expansion against the tooth walls, whereas a composite stays in place only by adhesion.”
Moisture such as saliva or blood can adversely affect the adhesive effect, leading to poorer adhesion and microleakage. Composite shrinkage can also compromise the seal of the filling, increasing the risk of cavities reoccurring.
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“The composite must be precisely worked to ensure durability,” the dentist said. “That is why we are increasingly using what is known as an elastic barrier, which has been reimbursed by the National Health Fund (CNS) from 2024.” An elastic barrier, also called a dental barrier, is an elastic sheet used in dentistry to keep a specific working area in the mouth dry and isolated. A thin, flexible sheet of rubber is prepared with holes drilled for the teeth to be treated.
If the rubber dam cannot be placed, the dentist may use amalgam fillings in exceptional cases. These exceptions are allowed when amalgam treatment is necessary for medical reasons – for example, in patients who are uncooperative in treatment, for example because they suffer from psychiatric disorders. Amalgam is easier to handle under moist conditions, which can be beneficial in treatments performed under general anesthesia.
Old, intact amalgam fillings can be left in place
Old amalgam fillings generally do not need to be replaced. No action is required as long as the filling remains intact. “Patients who wish to have their amalgam replaced for cosmetic reasons or because it is no longer watertight can certainly do so,” Becker-Dubois said, but she also recommends using a rubber barrier to avoid contact with mercury.
Mercury itself is found in many areas of daily life, but its use is strictly regulated to reduce human and environmental exposure. It is important to properly dispose of mercury-containing products – such as thermometers or fluorescent lamps – and to minimize the consumption of mercury-contaminated food, especially for at-risk groups such as pregnant women or children. Fish, for example, can be contaminated with mercury. However, scientific studies do not indicate cause for concern.
