Evaluation of aerosols in a simulated orthodontic debonding procedure

The COVID-19 pandemic has raised many concerns with regards to transmission of viral particles through the aerosols generated during dental procedures. Currently, coronavirus has infected over 58 million Americans resulting in greater than 800,000 deaths. Therefore, it is important to understand the risk that dental practitioners assume when performing aerosol generating procedures. Recent evidence has suggested that coronavirus can be transmitted through aerosolized particles, but many questions remain regarding this concern, especially in an orthodontic setting. The aim of this study is to quantify airborne concentration of MS2 near a dental mannequin during a simulated orthodontic debonding procedure and behind the personal protective equipment (i.e., face shield) of the provider. A simulated deband was performed 10 times on a dental mannequin with high-speed suction, but without water. The facial surface of all typodont teeth were coated with 1 mL of PBS buffer containing MS2 prior to enamel cleanup. Optical particle counters and air samplers were used to measure particle concentration and to collect virus aerosol generated during the procedure near the oral cavity and behind the clinician’s face shield. Double layer plaque assay with pour plate technique was used for enumeration of MS2 concentrations (PFU/m³) to determine the viable virus airborne concentration. When comparing the two measuring locations, near the oral cavity and behind the clinician’s face shield, there was no statistically significant difference of virus concentrations or particle size distribution. These results suggest that a face shield does not provide increased protection from live virus aerosol during deband procedures.