“Gray” fillings—professionally known as dental amalgam restorations—have been widely used for about 150 years. Amalgam is an alloy containing about 50% mercury plus other metals such as silver, tin, copper, and zinc. Today amalgam fillings are recognized as a major ongoing source of mercury exposure for the general population, and concern is growing. Mercury is a toxic, neurotoxic element whose primary target organ is the central nervous system; it can also affect the kidneys, respiratory system, and blood. Because of mercury toxicity, its use has been limited or banned in several countries, including Switzerland, Germany, Austria, the Netherlands, Italy, France, and Canada. The World Health Organization (WHO) has also set a goal to phase out medical use of mercury-containing products and to advance a global plan to gradually discontinue dental amalgam.
The amount of mercury released from amalgam restorations varies with the number of restorations, their size, and amalgam composition. Local stimuli such as brushing, tooth grinding, and chewing can increase mercury vapor release from the restoration.
Wi‑Fi is a technology for local computer networking, now found in almost every private home as well as public settings such as schools and hospitals. Low-cost wireless routers and convenience of use have driven rapid adoption—alongside public-health concern about potential harms from exposure to non-ionizing radiation from these devices.
A study published last year examined what happens when teeth with amalgam restorations are exposed to wireless radiation from routers. Researchers used extracted teeth and placed amalgam restorations of uniform size according to the manufacturer’s instructions. Teeth were then stored in saline at body temperature for 14 days (mercury release from amalgam gradually declines and stabilizes from day 14). Teeth were moved into tubes containing saliva-like fluid and exposed to radiofrequency radiation from a standard home 2.4 GHz router for 20 minutes at a fixed distance of 30 cm. During the experiment, data were transferred between the router and a wireless computer 20 meters away. A control group of teeth not exposed to this radiation was kept outside the experiment room. Differences in mercury released into the saliva-like fluid were then measured. Mercury concentration was about twice as high (!) in the Wi‑Fi–exposed group versus controls, with statistically significant differences. This study joins others that examined mercury release from amalgam after exposure to electromagnetic fields from sources such as mobile phones and MRI devices and found similar findings.
It is important to remember this is a single study from which definitive conclusions cannot be drawn alone—but it raises important questions that add to the many arguments against amalgam use in dentistry. At an EU institutions conference held late last year in Brussels, it was decided to legally ban amalgam use in children under 15 and in pregnant and breastfeeding women. That decision is part of a broader plan to eliminate amalgam use in dentistry across Europe, aligned with WHO policy and commitments by 140 countries under the Minamata Convention (2013).
To read more about amalgam and mercury fillings and how they can be replaced safely, click here.