Ultra-high-strength magnetic resonance imaging (MRI) approved by the U.S. Food and Drug Administration (FDA) in 2017¹ may pose a risk to people with mercury fillings. Also known as a 7-Tesla, or 7T MRI, they offer better image quality, particularly for visualization of smaller structures and subtle pathologies, than the lower strength 1.5T MRIs found in most hospital settings.

However, the strong magnets and higher magnetic field strength also carry additional risks, including to those with amalgam fillings, which are composed of 50 percent mercury. 

Should the powerful MRIs cause the toxic heavy metal to leach out of the filling, it could prove disastrous, as mercury is a known neuro- and reproductive toxin. It’s already known that mercury vapors leak out of fillings in scenarios that are far less intense than getting an ultra-powerful MRI, such as when you chew food or gum, when you brush your teeth and when you grind your teeth² — so it’s not a stretch that it could also leak out during a powerful medical scan like 7T MRI.

‘Very High’ Levels of Mercury Released After Ultra-High-Strength 7T MRI

Researchers from Akdeniz University in Turkey put extracted human teeth with amalgam-filled cavities in a solution of artificial saliva, then scanned them in a regular 1.5T MRI or an ultra-high-strength 7T machine for 20 minutes. They then measured the saliva’s mercury concentrations, which were found to be significantly elevated: They contained about four times more mercury than the 1.5T group.³

The levels were so high that the researchers said it could pose a risk not only to the patients but also the nearby medical staff. “In our study we found very high values of mercury after ultra-high-field MRI,” said Selmi Yilmaz, a dentist and faculty member at Akdeniz University, in a news release. “This is possibly caused by phase change in amalgam material or by formation of microcircuits, which leads to electrochemical corrosion, induced by the magnetic field.”⁴

The study didn’t test what health effects could occur from the mercury release, but past research suggests there’s reason for concern. According to the study authors, writing in the journal Radiology:⁵

“The release of mercury from amalgam fillings occurs through metal ions (mercury ions) and evaporation of mercury (elemental). Various conditions that occur during and after the restoration process, such as chewing, brushing, and corrosion, result in mercury discharge. 

Although approximately 40 percent of the mercury released from amalgam passes into the saliva in the form of metal ions and enters the gastrointestinal system (10 percent is absorbed), 60 percent is released as mercury vapor and is either inhaled and enters the circulation in the lungs or is exhaled. It has been suggested that release of mercury into the environment during the application or removal of amalgam may also have some potentially detrimental effects on the body.”

While the ultra-high-strength 7T MRIs are currently primarily used only for research purposes, there’s no guarantee that they won’t find their way into clinical settings — and imagine the ramifications for people with mercury fillings if they did. Yilmaz and colleagues have three additional studies underway looking at how these MRIs affect dental amalgam, but any additional mercury release is something that should be ardently avoided. It’s just one more reason why mercury in dentistry should become a thing of the past.

Banning Mercury in Dentistry: EU Bans Amalgam in Children

The use of mercury in fillings has fallen out of favor with many dentists and informed members of the public, but 100 million amalgams are still placed every year in the U.S. Other countries, including Sweden, Norway, Denmark and Germany, have taken a much more proactive stance and have banned or restricted the use of the toxic metal in dentistry. Meanwhile, as of July 1, 2018, amalgam use is banned for children under the age of 15 and for pregnant or breastfeeding women in all 28 countries of the European Union (EU).

Next, each country in the EU must submit a plan for how they are going to reduce amalgam use in the remainder of the population. The most vulnerable, the children, are now protected from the dangers of amalgam, but in all reality, amalgam should not be placed in anyone of any age or gender. These plans are due by July 1, 2019, and by then, it’s likely that most countries will opt to phase out amalgam entirely. 

As for the U.S. and Canada, now that so many other countries have taken a strong stance to protect the health of children and pregnant/nursing women, the FDA and Health Canada will be pushed to reconsider their stance, which so far has only protected amalgam producers and the profits of pro-mercury dentists. Worldwide, experts are increasingly calling for a ban on mercury amalgam in dentistry. 

This includes in Bangladesh, which has signed the Minamata Convention on Mercury, which mandates that governments take specific steps to reduce use of amalgam. The Minamata Convention took effect in August 2017, which meant countries that have ratified the treaty must take steps to reduce use of mercury amalgam.

In March 2018, the Bangladesh Dental Society also followed in the EU’s footsteps, announcing that amalgam should not be used in children and pregnant or nursing women, with plans to systematically eliminate the toxin from dentistry as a whole.⁶

Seeing the EU decision as a springboard, Consumers for Dental Choice and the World Alliance for Mercury-Free Dentistry have launched a campaign to ban mercury amalgam for every child everywhere. “The next generation of Europe’s children are safe from toxic dental mercury,” Charlie Brown, president of Consumers for Dental Choice and the umbrella World Alliance for Mercury-Free Dentistry, stated.

“We target 2020 as victory year for the world’s children,” said Brown. “This victory for Europe’s children will lead us to for the children of Asia, Africa and America North and South. Amalgam belongs only in museums that feature failed medical strategies.”