The pollution prevention goal with regard to mercury in dental offices is to minimize the amount of mercury that enters the environment. Mercury can enter the environment from a dental office by vaporization into office air during mixing of mercury amalgam, and by disposal of mercury amalgam mixing material and old fillings down the drain or in the regular trash.

One way to minimize the amount of mercury that enters the environment is to use non-mercury products in the dental office. Non-mercury restorative fillings and crowns include composite, glass ionomer, gold foil, cast gold alloy and metal-ceramic crowns. Non-mercury blood pressure devices include aneroid and digital models. Non-mercury alternatives to mercury fever thermometers include digital, indium-gallium-tin and dot matrix thermometers. Non-mercury thermostats include electronic models.

Dentists can implement a mercury pollution prevention program that should include the following:

• commitment to consistent administration of the pollution prevention program
• written policy regarding mercury
• training for staff in proper mercury handling and spill clean up
• product substitution of non-mercury alternatives
• good housekeeping
• mercury inventory control
• recycling

Specific pollution prevention opportunities and best management practices for mercury in dental offices include the following:

• Switch from bulk mercury to precapsulated amalgam. The American Dental Association has recommended eliminating the use of bulk dental amalgam mercury and bulk amalgam alloy in dental offices.
• Limit the amount of amalgam generated to only the amount needed for each restoration.
• Use gauze to retrieve excess amalgam during placement. Larger particles should be stored and recycled.
• Capture amalgam particles in traps and screens before water is discharged to the sewer. Some states recommend disposable, 40 mesh traps.
• Keep mercury and amalgam particles out of the drain and the regular trash.
• Collect and store mercury, amalgam particles and used, disposable traps and filters in properly labeled, airtight containers and send to a mercury recovery facility. Consult your state's hazardous waste regulations for proper labeling and storage.
• Install an amalgam separator.

Sources: Massachusetts Water Resources Authority and Massachusetts Dental Society, "Dentistry and the Environment," January 1988; Water Environment Federation, "Controlling Dental Facility Discharges in Wastewater: How to Develop and Administer a Source Control Program," 1999.