Occupational Exposure to Mercury in Dental Professionals Performing Mercury Dental Amalgam Restoration Removal Procedures: A Computational Fluid Dynamics Air Quality Risk Assessment Model Supported by In-Vitro Results

Aim: To quantify risks associated with exposure to dental amalgam mercury resulting from aerosolization during and following dental fillings removal procedures performed by dental professional over a lifetime of professional practice. Methods: A computational fluid dynamics model was generated using particle size, density, and compositional data obtained from in-vitro aerosolization experiments simulating the environment and breathing conditions of a dental professional performing a dental amalgam restoration removal procedure. Analysis was carried out using scanning electron microscopy and inductively coupled plasma – optical emission spectrometry. Data was collected in 2018-2019. Results: Experiments reveal that approximately 58% of mercury contained within the amalgam material is vaporized during removal procedures, and that aerosolized particles, ranging in size from 0.85 to 570 microns, may remain in suspension for nearly two minutes in the area surrounding the working surface. For dental professionals performing on average 9 such restorations per week, the estimated chronic daily intake (CDI) of mercury is 49 micrograms/kilogram-day, which exceed – by more than 20 times – the CDI recommended by the World Health Organization. Data analysis was performed in 2019. Conclusion: Because the CDI exceed recommended safe exposure limits, dental professionals should wear respiratory and personal protective equipment to protect them from exposure to both mercury vapour and mercury-containing particulates for at least two minutes following removal procedures.