Inquiries regarding the health risks of amalgam fillings, AKA silver fillings, are frequently raised by my patients. Lets first discuss what exactly amalgam fillings are composed of. Dental amalgam fillings are 50% liquid mercury and the remaining is powdered alloy made up of mostly silver, tin, and copper. Used for over 150 years, amalgam was the leading restorative material for fillings until the early 1990′s when composite tooth colored glass ionomer material became more widely used.
When an amalgam filling is originally placed in our tooth, it is soft and malleable in order for dental professionals to carve and form the filling. The material hardens at mouth temperature over a 24 hour period. Amalgam material is very durable, highly resistant to wear and fractures. I have had patients with silver fillings that are over 30 years old still in good condition, no breakdown or evidence of decay around the filling. If an amalgam filling is still intact, should you replace it anyways in order to get the mercury out of your mouth? What is the real risk of mercury fillings and should you be concerned?
There are a few forms of mercury, the kind found in amalgam (elemental mercury) is a different form than found in fish (methylmercury). The form of mercury associated with dental amalgam release mercury vapors and in this form is absorbed by the lungs. Inhalation of a high amount of liquid elemental mercury can have adverse affects on the brain and kidneys. According to the FDA, the low-level of mercury vapors we are exposed to from amalgam fillings is well below the level at which we would experience any health risks. However the argument can be made that no amount of mercury exposure can be considered harmless.
Replacing an amalgam filling is typically recommended by your dentist for a few reasons.
- The filling is “leaking”: this term is used when an amalgam filling begins to deteriorate from corrosive environmental or chemical factors, such as severe acid reflux or chronic soda pop exposure. As the silver filling breaks down it leaks into the dentin tubules creating a dark grey, blue or black appearance in the surrounding enamel.
- The filling has “open margins”: where the amalgam filling and the tooth meet is the margin. As an amalgam ages it can shrink back from the margin creating a gap, this is an open margin. Marginal corrosion can also occur from the same environmental and chemical factors that cause leakage.
- The filling has “recurrent decay”: once an amalgam filling has open margins, bacteria now have access to an area that is not only weak but inaccessible by brushing or flossing our teeth. The bacteria that live in our mouth produce lactic acid which increases the rate of marginal breakdown , and also creates areas of decay under the filling. This is not considered new decay, but a cavity that has “re-occurred” in an area that already has dental material in or around it. This is why we call in recurrent decay.
- The filling “fractured”: over time biting forces reduce the strength of any filling material which can create stress fractures internally (inside the tooth) or externally (outside the tooth). Either type compromises the integrity of the filling and can result in part of the tooth and/or filling fracturing out.
If none of these scenarios exist, is it still in your best interest to seek getting your silver fillings out? The FDA and the ADA say no. If the filling is in good condition with no recurrent decay and you have no known metal allergy, it is recommended to leave them alone. Removing an amalgam filling releases mercury vapors more concentrated than the filling itself if left intact. If you need a new filling, your dentist most likely does not even offer amalgam material since the new age materials are both more aesthetically pleasing and less controversal. The risk of leaving a silver filling in good condition alone is not really considered a risk since mercury vapors released are minimal and no conclusive evidence exists that links sound amalgam fillings to health problems. If you do have amalgam fillings and are experiencing chronic irritation in the mouth near or around these fillings it might be wise to determine if you do in fact have existing metal allergies.
After discussing your concerns with your dentist and dental hygienist and getting educated on the pros and cons, the ultimate well-informed decision should always be one that you are comfortable with and in the best interest of your overall health.
In Health, Katie RDH