Mercury generation potential from dental waste amalgam

Area of Science:

• Environmental Science
• Dental Public Health
• Materials Science

Background:

• Dental amalgam, a mercury-containing alloy, is widely used for dental restorations.
• Amalgam waste management is crucial due to mercury's environmental and health risks.
• Quantifying amalgam waste generation is essential for developing effective disposal and recycling strategies.

Purpose of the Study:

• To quantify amalgam usage and waste generation in Illinois dental offices.
• To estimate the proportions of non-contact, contact, and tooth-retained amalgam.
• To project national amalgam waste generation and recycling potential.

Main Methods:

• Collected non-contact and contact amalgam waste from six dental offices over a defined period.
• Conducted an in vitro study to determine amalgam distribution (tooth-retained, non-contact, contact).
• Adjusted data by dental chair numbers and working days for comparable estimates.

Main Results:

• Median non-contact amalgam generation was 421 mg/day/chair; contact amalgam was 64 mg/day/chair.
• In vitro study showed 46% retained in tooth, 43% as non-contact, and 11% as contact amalgam.
• Illinois dentists could generate 947 kg of recyclable non-contact mercury and 144 kg of contact mercury annually.

Conclusions:

• Dental practices in Illinois have the potential to generate substantial amounts of recyclable mercury.
• A significant portion of dental amalgam waste is contact amalgam, posing environmental disposal challenges.
• Extrapolated national estimates suggest over 18,000 kg of recyclable mercury and nearly 3,000 kg of contact mercury generated annually by US dentists.