Dental amalgam has long been recognized as a safe and affordable material for fillings. However, the American Dental Association (ADA) acknowledges that amalgam waste from dental offices in the United States contribute 29.7 tons of mercury pollution to wastewater systems each year. This statistic prompted the Environmental Protection Agency (EPA) to finalize regulation on the use of amalgam separators in 2017.
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This article provides an overview of the use of amalgam separation in the dental office, including the ADA’s best practices on amalgam separators.
Dental Amalgam and Mercury Pollution
Dental amalgam consists of approximately 40 to 50% mercury, 25% silver, and 25 to 35% mixture of copper, zinc and tin. These materials are bound together as a hard, stable substance.
Amalgam has been subject to numerous studies and reviews that demonstrate it is safe and effective for use in dental fillings. The problem with amalgam is not its effect on dental patients, but rather the difficulty of disposing of dental amalgam safely.
When dentists place new amalgam fillings or remove old ones, water containing amalgam particles is flushed into chair-side drains. These mercury-containing particles then enter the wastewater disposal system and water treatment plants. From there, the amalgam particles may be incinerated, land-filled, or made into fertilizer pellets for lawns or gardens. In each case, mercury from amalgam fillings is discharged into the environment, where it may bioaccumulate in fish and contaminate the food chain.
To summarize, dental offices that work with amalgam fillings (including “mercury-free” practices that only remove them) flush amalgam particles containing mercury down the drain and into the wastewater system. These particles ultimately become environmental pollutants.
One survey found that dental amalgam is the greatest contributor of mercury pollution in the wastewaters of California, Minnesota, Ohio, and Maine; numerous studies have also identified the dental industry as the top source of mercury in sewers in Canada and Europe.
Regulating the Use of Amalgam
The EPA’s National Pollution Discharge Elimination System (NPDES) mandates the reduction of mercury and other contaminants to ensure the discharge does not negatively affect water quality or people’s health. On July 14, 2017, the agency finalized regulation specifically targeting the use of dental amalgam.
The regulation applies to most dental practices that discharge waste into a public sewer or wastewater system. The basic requirements are:
- Using amalgam separators (or equivalent devices) to remove dental amalgam solids from all amalgam process wastewater;
- Implementing best management practices;
- Complying with reporting requirements; and
- Maintaining certain records documenting compliance.
Practices have until July 2020 to comply.
What Are Amalgam Separators?
An amalgam separator is a device installed on a dental vacuum line to filter out mercury and other particles from water waste before they enter the sewer system. The captured mercury can then be recycled to industry or safely disposed of.
Traditionally, dental practices used chair-side traps and vacuum filters to capture amalgam waste; however, the ADA estimates that 6.5 tons of mercury bypass these filters annually.
Amalgam separation is proven to reduce the impact of amalgam on environmental pollution. In Toronto, the amount of mercury in wastewater sludge decreased by 58% after regulation requiring the use of amalgam separators in dental offices took effect.
In addition to reducing environmental pollution, using an amalgam separator can help to extend the life of vacuum pumps by preventing solid particles from entering and damaging the pump.
To comply with EPA regulation, an amalgam separator must be ISO 11143:2008-certified to remove greater than 95% of solids by weight. Most amalgam separators on the North American market meet this standard.
Amalgam Separation Best Practices
To assist in complying with the new regulation, the ADA has published best practices for the use of amalgam separators. These practices recommend that dental practitioners:
- Use chair-side traps, vacuum pump filters, and amalgam separators to capture and recycle amalgam particles.
- Use pre-capulated mercury alloys instead of bulk mercury in amalgam fillings.
- Salvage, store and recycle scrap amalgam whenever possible, including amalgam pieces from restorations and used disposable amalgam capsules.
- Recycle teeth that contain amalgam restorations (ask your recycler whether these teeth must be disinfected first).
- Never dispose of amalgam waste in biohazard containers, regular garbage, or down the drain.
- Flush wastewater lines with line cleaners that minimize dissolution of amalgam (like BioPure Evacuation System Cleaner) instead of bleach or chlorine cleaners.
By implementing these practices and following the EPA regulation, dental practitioners, specialists, and registered dental hygienists can work towards reducing their impact on the environment.
Contact us to learn more about line cleaners that minimize amalgam dissolution. We look forward to assisting in building a more sustainable dental practice.