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

Abstract

Adelle Leonard, Louise Meunier

Aims: 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, den-sity, and compositional data obtained from in vitro aerosolization experiments simulat-ing the environment and breathing conditions of a dental professional performing a den-tal amalgam restoration removal procedure. The analysis was carried out using scanning electron microscopy and inductively coupled plasma—optical emission spectrometry. Data were 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 parti-cles, ranging in size from 0.85 to 570 microns, may remain in suspension for nearly 2 minutes in the area surrounding the working surface. For dental professionals perform-ing on an average nine such restorations per week, the estimated chronic daily intake (CDI) of mercury is 49 μg/kg day, which exceeds—by more than 20 times—the CDI rec-ommended by the World Health Organization. Data analysis was performed in 2019.Conclusion: Because the CDI exceed recommended safe exposure limits, dental pro-fessionals should wear respiratory and personal protective equipment to protect them from exposure to both mercury vapor and mercury-containing particulates for at least 2 minutes following removal procedures