By Heather Mistretta
Mercury is in the air, water and soil. In fact, it’s even in the earth’s crust! It’s natural, so that’s good,
right? Well, according to some, that might not be the case. And as the old adage says, too much of a
good thing can be bad.
The most common way mercury is used is in dental fillings. The substance, dental amalgam, is a liquid
mercury and metal alloy mixture used to fill cavities caused by tooth decay.
For years, modern dentists have been using dental amalgam, but the history of its medical effectiveness
can actually be traced all the way back to the Tang Dynasty around 659, with evidence of its usage
appearing in Germany in 1528. In the 1800s, amalgam became the dental restorative material of choice
due to its low cost, ease of application, strength and durability.
Although the efficacy of those benefits cannot be refuted and it has long been touted as a relatively safe
restorative material when used in low doses, concerns have been growing in recent years about the
potential for mercury poisoning and reports of acute though rare allergic reactions to it.
These critics argue that it has toxic effects that make it unsafe, both for the patient and perhaps even
more so for the dental professional manipulating it during a restoration. One hazard, they say, is that
the amalgam vapor can be released through chewing. The vapors readily pass through cell membranes,
across your blood-brain barrier, and into your central nervous system. The result can be psychological,
neurological and immunological problems, particularly in children and fetuses, whose brains are still
Also, it has been argued that an increased release of mercury can ensue following the exposure of
electromagnetic fields generated by Wi-Fi routers and mobile phones.
More isn’t always better, says the University of Georgia.
And one recent study has added even more weight to the argument that what goes in your mouth does
not stay in your mouth. The study by the University of Georgia’s department of environmental health
science in the College of Public Health reinforces that systemic connection between oral health and
overall health by drawing attention to the dangers of mercury exposure in these conventional dental
The comprehensive study, which eclipsed some of the more inconsistent, inconclusive studies done in
the past, concluded that these fillings significantly contribute to prolonged mercury levels in the
body—a scary thought to many.
The research, which analyzed data from nearly 15,000 individuals, is the first to demonstrate a
relationship between dental fillings and mercury exposure in a nationally representative population.
Researchers analyzed the levels of several types of mercury in these people, placing them in groups
based on the number of fillings they had received over the course of their lifetimes–either zero, one to
eight or more than eight.
The study, which was the first to also control for age, education, ethnicity, race, gender, smoking and
seafood consumption, a known carrier of mercury. The study went one step further by analyzing
exposure by specific types of mercury. Researchers found a significant increase in methyl mercury, the
most toxic form of mercury. This finding suggests the human gut microbiota, a collection of
microorganisms living in the intestines, may transform different types of mercury. What this means is
that because half of the dental amalgam is made up of mercury, methyl mercury may cause damage
even at low levels.
The results of the University of Georgia study show that individuals with more than eight dental surface
fillings had about 150 percent more mercury in their blood than those with none. The average American
has three dental fillings, while 25 percent of the population has 11 or more fillings.
So, what’s the alternative, you ask? According to this study and many holistic dentists, the answer is
dental composite resins, a mercury-free alternative for dental fillings. Although they can release small
amounts of bisphenol A, or BPA, which may cause developmental or reproductive damage, the results
found no association between dental fillings and urinary BPA.
Dental composite resins are types of synthetic resins, which evolved as restorative materials since they
were insoluble, aesthetic, insensitive to dehydration, easy to manipulate and reasonably inexpensive.
Introduced in the 1970s, these resins evolved into hybrid composites in the 1980s and then improved
significantly in the 1990s and 2000s when scientists developed ways to make them a lot stronger.
Mercury is still widely used in dentistry. Dentists, like many people, are creatures of habit. But like
anything, just because something has been used for a long time, does not mean it is the best. It is
important for researchers to continue to delve into studies that alternative products and approaches
that are both effective and healthy.