For over a century, when encountering tooth decay, dentists have turned to amalgam putty as a solution. Dental amalgam is considered a safe and effective method for providing relief to the patient and preserving healthy tooth structure. However, since amalgam does contain a high percentage of elemental mercury, there are stringent regulations in place concerning its formation, use, and disposal. In this post we are going to discuss:
What is Amalgam?
Where is Amalgam Found?
Regulations Concerning Dental Amalgam
What is Amalgam?
Amalgam putty is a combination of metal alloy (a mixture of two or more metals) and elemental mercury. Today’s low-copper dental amalgam typically consists of 50% mercury, 22-32% silver, ~14% tin, ~8% copper, and a few other trace metals. (1) Mercury is the element of choice in dental amalgam, as it is liquid at room temperature and therefore able to bond with metal alloy. Once the metal alloy and mercury are bonded, the amalgam putty becomes solid and durable.
According to the FDA: “When placing dental amalgam, the dentist first drills the tooth to remove the decay and then shapes the tooth cavity for placement of the amalgam filling. Next, under appropriate safety conditions, the dentist mixes the powdered alloy with the liquid mercury to form an amalgam putty. This softened amalgam putty is placed and shaped in the prepared cavity, where it rapidly hardens into a solid filling.” (2)
Where is Amalgam Found?
Amalgam is typically found in dental offices, as it is ideal for filling cavities in decayed teeth. The earliest recorded use of dental amalgam dates back to 659 AD to the Tang Dynasty in China, where records show that cavities in teeth were filled with a metal alloy consisting of silver and tin. (3) According to Geir Bjørklund, early amalgam was made by mixing mercury with silver coins. (4) Amalgam was then brought to the United States from Europe in 1833, and quickly became dentists’ choice in cavity-filling, due to its durability and the ease of access to materials needed to create it. (1)
Regulations Concerning Dental Amalgam
Due to the high percentage of elemental mercury used in dental amalgam, there are of course stringent regulations put in place to ensure its formation, use, and disposal are handled properly. The FDA states that, “Dental amalgam contains elemental mercury. It releases low levels of mercury in the form of a vapor that can be inhaled and absorbed by the lungs. High levels of mercury vapor exposure are associated with adverse effects in the brain and the kidneys.” (2) For these health reasons, the formation and use of elemental mercury are constantly examined for safety and effectiveness.
In regards to the disposal of dental amalgam waste, the environment is the concern. If not disposed of properly, amalgam waste containing mercury can be exposed to the environment and impact a community. To combat this risk, dental offices are required to make use of amalgam separators. Amalgam separators are machines that remove amalgam particles from the wastewater generated by dental offices. In a 2017 ruling, the EPA now requires amalgam separators to achieve at least a 95% removal efficiency. (5) Compliance with this EPA ruling is mandatory for all dental practices in the United States. The amalgam waste cannot be discarded in the trash once separated from the wastewater. Instead, it must be sent to a facility that specializes in melting the metals and recycling that mercury. Amalgam recycling keeps the discarded mercury from entering the environment. Utilizing an amalgam recycling ship-back system removes the issue of locating a proper amalgam waste facility.
The use of dental amalgam has been an effective method for filling in cavities formed through tooth decay for over a century. Utilizing elemental mercury can be hazardous towards the health of the patient if not mixed properly with the metal alloy, and standards are in place to combat the risks towards both the patient and the environment. Discarding of amalgam waste requires the use of amalgam separators that are regulated by the EPA for their efficiency at removing mercury from wastewater.
Please contact our specialists at 877-765-3030 if you have any questions or concerns about your state/local dental amalgam handling requirements. We can also assist you if you need help regarding the installation, operation and maintenance of our amalgam separators.
Sources:
(1) “Amalgam (Dentistry).” Wikipedia, Wikimedia Foundation, 4 Oct. 2018, en.wikipedia.org/wiki/Amalgam_(dentistry).
(2) Center for Devices and Radiological Health. “Dental Amalgam - About Dental Amalgam Fillings.” U S Food and Drug Administration Home Page, Center for Devices and Radiological Health, www.fda.gov/medicaldevices/productsandmedicalprocedures/dentalproducts/dentalamalgam/ucm171094.htm.
(3) Czarnetzki, A.; Ehrhardt S. (1990). "Re-dating the Chinese amalgam-filling of teeth in Europe". International Journal of Anthropology. 5 (4): 325–332.
(4) Bjørklund, G (1989). "The history of dental amalgam (in Norwegian)". Tidsskr Nor Laegeforen. 109 (34–36): 3582–3585. PMID 2694433
(5) Effluent Limitations Guidelines and Standards for the Dental Category[PDF]. (2017). EPA.
