Over the last century and a half millions of people have had a tooth cavity filled with “silver” amalgam. Perhaps you’re one of them. The use of this effective and durable filling has declined in recent years, but only because of the development of more attractive tooth-colored materials.
At the same time there’s another issue that’s been brewing in recent years about this otherwise dependable metal alloy: the inclusion of mercury in amalgam, about half of its starting mixture. Various studies have shown mercury exposure can have a cumulative toxic effect on humans. As a result, you may already be heeding warnings to limit certain seafood in your diet.
So, should you be equally concerned about amalgam fillings — even going so far as to have any existing ones removed?
Before taking such a drastic step, let’s look at the facts. To begin with, not all forms of mercury are equally toxic. The form causing the most concern is called methylmercury, a compound formed when mercury released in the environment combines with organic molecules. This is the form certain large fish like salmon and tuna ingest, which we then ingest when we eat them. Methylmercury can accumulate in the body’s tissues where at high levels it can damage various organ systems.
Dental amalgam, on the other hand, uses elemental mercury. Dentists take it in liquid form and mix it with a powder of other metals like silver, tin and copper to create a pliable paste. After it’s placed in a prepared cavity, the amalgam hardens into a compound in which the mercury interlaces with the other metals and becomes “trapped.”
Although over time the filling may emit trace amounts of mercury vapor, it’s well below harmful levels. You’re more likely to encounter “un-trapped” mercury in your diet than from a dental filling. And scores of studies over amalgam’s 150-year history have produced no demonstrable ill effects due to mercury.
Although it now competes with more attractive materials, amalgam still fills (no pun intended) a necessary role. Dentists frequently use amalgam in less visible back teeth, which encounter higher chewing pressures than front teeth. So, if you already have an amalgam filling or we recommend one to you, relax — you’re really in no danger of mercury poisoning.
One of the top concerns in public health today is exposure to the metallic element mercury within the environment. At abnormal levels, mercury can have a toxic effect on our nervous systems and cause other health problems.
These concerns over mercury have also increased attention on one material in dentistry that has included the metal in its makeup for over a century — dental amalgam for filling teeth. Amalgam is a metal alloy that can include, in addition to mercury, silver, tin, and copper. When first mixed dental amalgam is a moldable material used for fillings in prepared teeth. It then hardens into a durable restoration that can withstand biting forces.
While the use of amalgam has declined with the introduction of life-like colored fillings, it's still used for teeth like molars subject to high biting forces. With what we now know about the ill effects of mercury (which can make up to half of an amalgam mixture) is it safe to continue its use?
The American Dental Association has performed extensive research into amalgam safety. They've found that mercury is stabilized by the other metals in the amalgam. This prevents "free" molecules of mercury, the real source of harm to health, from escaping into the blood stream in the form of vapor. Although trace amounts of mercury vapor from the amalgam are released as a person chews, those levels are well below the threshold that could cause harm.
From a patient standpoint, the biggest drawback to dental amalgam isn't safety — it's the appearance of teeth it's used on. Silver fillings aren't considered attractive. And now there are viable filling alternatives that not only look like natural teeth but can withstand biting forces almost as well as amalgam. These materials include composite resins, mixtures of glass or quartz within resin, or glass and resin ionomers. Each of these has advantages and disadvantages depending on how and where they're applied.
After a thorough dental examination, we'll be able to advise you on what filling material will work best to produce the best result. And if we do suggest dental amalgam you can rest assured it will be a safe choice.