Posts for tag: fillings
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.
With all the new tooth-colored fillings for cavities, it's easy to overlook metal amalgam. While this mainstay of dental care for over a century might not be as attractive as composite resins or glass and resin ionomers, it still has the advantage of strength and durability.
Amalgam is a stable metal alloy usually made up of silver, tin, copper and mercury. The metals are proportioned and mixed precisely to guard against “free” mercury molecules, which could pose a health hazard. The mixture is pliable at first, but then sets hard once molded into the prepared area of the tooth.
Besides strength, amalgam's other advantages include low cost, high resistance to wear and biocompatibility (not toxic to the body or allergy-producing). At the same time, it can require more tooth structure removal to accommodate a filling and cause higher sensitivity to temperature for a while after installation. Its main disadvantage, however, is appearance — it's now considered unacceptable from an aesthetic point of view to use it in visible areas like the front teeth.
Because of this, materials resembling natural tooth color are coming into vogue, especially as their strength improves. Still, dental amalgam continues to play a useful role, especially in less visible back teeth with higher chewing forces.
One past concern about dental amalgam is the inclusion of mercury in the alloy. As mentioned before, mercury is hazardous in a “free” form when not knit microscopically with other metals; as such it can emit a vapor that could enter the bloodstream and damage the nervous system. But after several studies by various organizations, the American Dental Association has concluded amalgam's precise mixture prevents the mercury from taking this form: although some vapor is given off during chewing it's far too low in concentration to pose any danger.
Dental amalgam continues to be an effective choice for fillings. Whether it's the right choice for you will depend on the type and location of a tooth to be filled, and whether durability is a higher concern than appearance. If we do recommend an amalgam filling, you can be assured it's a safe and lasting choice.
If you would like more information on your choices for dental fillings, please contact us or schedule an appointment for a consultation. You can also learn more about this topic by reading the Dear Doctor magazine article “Silver Fillings — Safe or Unsafe?”