There are two main types of dental fillings: amalgam and composite. Dental amalgam or “silver” fillings have been used for over 200 years. Amalgam fillings are composed of a mixture of metals such as tin, silver, and copper bound together with mercury.
While there has been much controversy about the possible negative health effects of these amalgam fillings, the American Dental Association, the Centers for Disease Control and Prevention, The U.S. Public Health Service, National Institute of Health, and the World Health Organization are all confident that dental amalgam fillings are safe.
In fact, the Food and Drug Administration (FDA) issued its final regulation on dental amalgam in a press release dated July 27, 2009. After considering around 200 scientific studies, the FDA has classified dental amalgam and “its component parts – elemental mercury and a powder alloy” from Class I to a Class II “moderate risk” medical device. The new classification will allow the FDA to “impose special controls to provide reasonable assurance of the safety and effectiveness” of dental amalgam fillings.
The American Dental Association (ADA) issued a press release in response to the recent Food and Drug Administration’s announcement stating that they concurred with the FDA’s decision “not to place any restriction on the use of dental amalgam, a commonly used cavity filling material.” The ADA believes that dental amalgam fillings are “valuable, viable, and safe choice for dental patients.”
With today’s advances in dental materials, we can now use bonded resin fillings on back teeth. Strong, and durable, these fillings are a favorite because they match the color of your tooth.
Why don’t many dentists use amalgam filling anymore?
Thanks to continuing research, we now have more choices when it comes to filling materials. For example, we can now use composite, or “tooth-colored” fillings in the back of the mouth where chewing forces are the greatest. Composite fillings come in all shades and are quite natural looking. In addition, the dentist does not have to remove as much natural tooth structure to place a composite fillings as compared to placing the century-old old amalgam ones.
How can I get a cavity in a tooth that already has a filling?
No matter what type of filling material you have, every time you come in for a check-up, your dentist will carefully examine and evaluate your fillings to make sure they are flush with the tooth. As fillings get older they start to shrink and break down creating a gap between the filling and the tooth. When that happens, bacteria can get underneath the filling creating a new cavity (decay) under the old filling.
Why does my dentist want to replace my old filling with a crown?
When a filling needs to be replaced your dentist will check your tooth and your x-rays to see how big the existing filling is, and will decide if there will be enough tooth structure left to hold another filling. Most of the time that decision is pretty straight forward, however, because an x-ray is only a two-dimensional view of a three-dimensional object, sometimes your dentist won’t be able to predict what kind of restoration is needed until the old filling and decay is removed. At that time, if there is enough tooth structure left to hold another filling, your dentist will place another filling. If there is not enough tooth structure left, a crown will be needed to keep the tooth strong and healthy for years to come.