By Dr. Hector Saenz de Viteri Tejeda
Different types of biomaterials such as composites, resins, glass ionomers, gold, and amalgam have been used as direct restorative materials. Amalgam is probably the most popular dental restorative material that has ever existed. Dental amalgams have been used worldwide for more than 150 years, but in the last two decades there has been a much lower acceptance from patients due to beliefs about body and organ toxicity from the mercury and preferences for tooth-colored fillings instead of metal (silver).
What are they used for, and what are amalgam fillings made of?
Amalgam fillings are mostly used in dentistry to restore and fill decayed teeth with a material that is more long-lasting and affordable than tooth-colored filling material such as composite or resin.
A powdered alloy made of silver, tin, and copper gets mixed with liquid mercury to create a soft putty-type paste that can be packed into the tooth to fill the cavitation after decay has been removed. While the amalgam hardens, it allows the dentist to shape and create natural tooth anatomies. Amalgam will then become very strong and ready to be burnished and polished to gain a shiny appearance.
The use of amalgam fillings is safe; nothing has been proven to the contrary. But how can your dentist protect you from additional exposure to the amalgam mix or mercury vapors during the removal or placement of an amalgam filling? The use of a rubber dam to isolate the oral cavity from the working area can allow for excess of material or drilled amalgam to be collected without entering the oral cavity. Also, to protect the environment, dental offices are adapting amalgam trap collectors to avoid amalgams from going into the public sewage systems. Dental amalgam fillings that do not present decay and are in an acceptable condition should not be removed unless it is medically necessary.
It has been recommended that high-risk populations such as children (less than 6 years of age), people with neurological impairment or kidney disfunction, people with allergy to the amalgam components, nursing mothers, and women who are planning on getting pregnant avoid amalgam use and consider another treatment option.
Longevity of amalgams will depend on different factors such as the presence of secondary decay, marginal changes, and poor cavity preparation. Until there is an equivalent or better material created and as long as aesthetics is not a major concern, an amalgam filling may continue to be a great material of choice to restore a posterior tooth.
