Mercury Vapor Emission during Dental Amalgam Removal: A Comprehensive Assessment of Atmospheric Concentrations through Direct and Indirect Measurement Techniques

JÉRÔME DEVOY, French National Institute for Research and Safety, France

     Abstract Number: 632
     Working Group: Aerosol Exposure

Abstract
This study delves into the release of mercury vapor during dental amalgam removal procedures and employs both direct (LUMEX) and indirect (hydrar tube) techniques to measure atmospheric mercury concentrations. Dental amalgam, a composite of elemental mercury, silver, tin, and copper, undergoes mechanical and thermal forces during routine removal, resulting in the generation of fine particulate matter. This disturbance exposes liquid mercury to the air, leading to the volatilization of mercury vapor.

Utilizing high-speed drilling and other mechanical interventions, small particles are created, significantly increasing the surface area for mercury vapor release. The study involves a comparative analysis of atmospheric mercury concentrations measured directly using LUMEX and indirectly through hydrar tube methods during dental amalgam removal. This approach provides a nuanced understanding of the mercury release dynamics.

The results highlight the potential health risks associated with inhalation exposure, emphasizing the need for accurate measurement techniques.

Although there is a non-zero ambient concentration (10-150 ng/m3), the peaks of mercury concentration occur when opening the vials containing the mercury capsules (>20 µg/m3), when milling the dental amalgam (150-350 ng/m3) and when cleaning the work space (>20 µg/m3).

Chronic exposure to mercury vapor is known to have adverse health effects, particularly on the nervous system. Safety measures implemented by dental practitioners, such as high-volume suction, rubber dam isolation, and protective masks, are considered in conjunction with the measured mercury concentrations.

This study underscores the significant role of dental amalgam removal as a source of mercury exposure while offering a dual perspective through direct and indirect measurement techniques. Guidelines from dental organizations and health agencies, coupled with ongoing discussions in the dental and medical communities, underscore the importance of comprehensive strategies to mitigate mercury exposure risks. The comparative analysis of direct and indirect measurement results contributes valuable insights, aiding in the development of informed practices and policies in dental settings.