Performance evaluation of high-volume evacuation for removing droplets during dental treatment

The high-volume evacuation (HVE) is commonly employed as a primary source control measure for removing splatter emitted from mouth during dental treatments, but there is still a lack of comprehensive understanding of its efficiency. Based on our previous experiments on the emission characteristics during dental treatments, this study employed computational fluid dynamics (CFD) simulations to investigate the impact of emission parameters (droplet size, emission velocity, emission angle), HVE usage methods (distance between HVE and the droplet release source), and HVE suction flow rates on its removal efficiency. The effect of HVE on fallow time (FT) was also examined. Cumulative removal efficiency that accurately reflected the HVE effect was proposed as an evaluation index. It was found that emission velocity and distance between HVE and the source were key factors determining cumulative removal efficiency. When the distance was 4 cm, the cumulative removal efficiencies for low-velocity (0.8 m/s), medium-velocity (3.4 m/s), and high-velocity droplets (6.0 m/s) were approximately 97.9%, 73.6%, and 58.0%, respectively. For high-velocity droplets at 6.0 m/s, decreasing the distance from 4 cm to 2 cm and 1 cm increased the cumulative removal efficiency from 58.0% to 76.7% and 100%. This study was expected to enhance the understanding of HVE performance and provide information on its usage method. It also indicated the need for developing advanced control measures that could have high efficiency in removing both low-velocity and high-velocity droplets.