Creating a healthy oral environment involves many components, one of which is replacing old fillings that are breaking down or leaking. Amalgam fillings, commonly referred to as “silver” or “mercury” fillings are one of the biggest reasons for replacement restorations. The metal nature of the material causes it to contract and expand as hot and cold elements enter the oral cavity, which results in a breakdown of the material and often cracks in the teeth. Once the material is compromised or a crack in the tooth is evident, microscopic bacteria is then able to penetrate the enamel and dentin of the tooth and cause recurrent decay. This leads to the need for a replacement restoration to prevent larger problems down the road.
Many patients get concerned over having these fillings removed safely or may even want them removed preemptively because of their concerns over mercury exposure. At this point, it’s important to gather the facts before making any decisions on treatment. Here we will discuss the properties and benefits/risks of amalgam fillings to help guide your decision making.
Amalgam fillings are approximately 50% elemental mercury, but are also composed of tin, copper and silver. The reason that mercury is used is because it bonds well to the other mixture of metals, is malleable (able to be shaped to fit the shape of the tooth), and is extremely durable. The important distinction is that the type of mercury used is elemental which means that the risk is for the mercury to be inhaled as a vapor. Originally amalgam fillings were thought to be completely inert once the liquid mercury and the alloy powder were mixed, and therefore harmless in terms of vapor inhalation of mercury. More recently however, sophisticated tests have shown that small amounts of the vapor can be released as the amalgam filling wears. It’s important to note three things about mercury vapors, however. One, in the mouth, saliva creates a water/protein barrier that significantly reduces the amount of vapor created. Two, the amount of vapor actually released is in the billionths of an ounce. And three, the ADA has stated it would take at least 300 amalgam fillings in the mouth for a person to have any adverse side effects from mercury vapors.
As far as removal of amalgam fillings, your dentist will be using copious amounts of water and a securely placed high-speed suction to provide safe removal of the amalgam and any residue left behind. Those techniques alone will eliminate over 90% of amalgam exposure to the patient. A rubber dam is also available to isolate the tooth being worked on the prevent any possibility of exposure during removal. Please advise your dentist if this is something you’d like to have during your procedure.
Elective removal of amalgam fillings is not currently recommended by the FDA or the ADA. Due to the high amount of evidence supporting the safety of amalgam use over the last 150 years as well as considering that removing a sound amalgam filling will also remove healthy tooth structure, these combined considerations do not support the unnecessary removal of amalgam fillings. If you have any further concerns over the safety or the esthetics of your existing amalgam fillings, please consult with your dentist. An open dialogue will lead to higher patient comfort and a better acceptance of treatment if you understand that safety and durable, quality restorations are our highest priority.
Paige Tscherpel, RDH, BSDH
Consulted sources include:
http://www.ada.org/~/media/ADA/Member%20Center/FIles/safety.ashx
http://www.colgate.com/en/us/oc/oral-health/procedures/fillings/article/dental-amalgam-a-health-risk