Key points:
Current estimates indicate that less than 1% of the mercury released into the environment comes from dental preparations and uses.1, 2The majority of mercury from dentistry-related origin is in the form of elemental mercury in amalgam and not methylmercury, which is the form of mercury of particular environmental concern. After elemental mercury is released in the aquatic environment, some bacteria can transform it into methylmercury, a toxic form of mercury that can accumulate in fish and shellfish.3;Notwithstanding, following are insights about stewardship efforts with respect to dental amalgam in the waste stream.
American National Standards Institute/American Dental Association (ANSI/ADA) Standard No. 109 defines amalgam waste as including amalgam (scrap), chair-side trap filters containing amalgam, vacuum pump filters containing amalgam, saliva ejectors if used in dental procedures involving amalgam, used amalgam capsules, extracted teeth with amalgam restorations, and waste items that are contaminated with amalgam.4
Dental best management practices for amalgam waste handling and disposal4 include use of chair-side traps, use of amalgam separators, regular inspection and cleaning of traps, and use of appropriate commercial waste service to recycle and/or dispose of collected amalgam (Table). Compliance with the EPA final rule on amalgam separators is required.
Table. Best management practices for amalgam waste5
| Do |
Don't |
| Do use precapsulated alloys and stock a variety of capsule sizes |
Don't use bulk mercury |
| Do recycle used disposable amalgam capsules |
Don't put used disposable amalgam capsules in biohazard containers |
| Do salvage, store, and recycle non-contact (scrap) amalgam |
Don't put non-contact amalgam waste in biohazard containers, infectious waste containers (red bags), or regular garbage |
| Do salvage (contact) amalgam pieces from restorations after removal and recycle their contents |
Don't put contact amalgam waste in biohazard containers, infectious waste containers (red bags), or regular garbage |
| Do use chair-side traps, vacuum pump filters, and amalgam separators to retain amalgam and recycle their contents |
Don't rinse devices containing amalgam over drains or sinks |
| Do recycle teeth that contain amalgam restorations (Note: Ask your recycler whether extracted teeth with amalgam restorations require disinfection) |
Don't dispose of extracted teeth that contain amalgam restorations in biohazard containers, infectious waste containers (red bags), sharps containers, or regular garbage |
| Do manage amalgam waste through recycling as much as possible |
Don't flush amalgam waste down the drain or toilet |
| Do use line cleaners that minimize dissolution of amalgam |
Don't use bleach or chlorine-containing cleaners to flush wastewater lines |
Amalgam separators remove amalgam particles from the wastewater to reduce the amount of amalgam entering the sewage system. Amalgam separators are devices designed to capture amalgam particles from dental office wastewater through sedimentation, filtration, centrifugation, or a combination of these mechanisms.6 Some separators may also use ion exchange technology to remove mercury from wastewater.6 Whenever there is need for plumbing work or other activities that might dislodge amalgam waste adhering to the inside of the pipes, it is recommended that steps be taken to minimize potential health or environmental issues.
The Environmental Protection Agency (EPA) regulation on the use of amalgam separators was finalized7 and was effective as of July 14, 2017, with the date for compliance being July 14, 2020.
Last Updated: August 8, 2022
Prepared by:
Research Services and Scientific Information, ADA Library & Archives.
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