Characteristics of Aerosols Generated from an Ultrasonic Scaling Device and Prevention of Diffusion by Intra- and Extraoral Suction Devices

Abstract

Aerosol infection is one of the routes of transmission of the new coronavirus (COVID-19), which continues to rage around the world. Aerosols generated by ultrasonic scalers, which are frequently used in periodontal treatment, are of concern as a source of cross-infection, but the characteristics of the aerosols are not clear. The purpose of this study was to investigate the characteristics of aerosols generated by ultrasonic scalers through fluid engineering studies using a particulate visualization system, and to evaluate the effectiveness of intra- and extraoral suction devices in preventing aerosol diffusion through simulated clinical studies using water-sensitive test papers and particle counters. From the fluid engineering study, the average particle size of the aerosol generated by the ultrasonic scaler was found to be about 40 μm, and the droplet velocity to be 3 m/s. A clinical study using water-sensitive test papers revealed the effect of the orientation of the ultrasonic scaler on the direction of aerosol dispersal. In addition, analysis using a particle counter showed that the amount of aerosol with a particle size of 1-10 μm dispersed decreased with the distance, and it was confirmed that the amount of aerosol decreased significantly with the use of intra-oral vacuum suction. These results suggest that the risk of cross-infection via aerosols can be suppressed by appropriate use of a suction device for aerosols of various particle sizes generated by ultrasonic scalers.