Large eddy simulation study on dental spray dynamics and infection during ultrasonic atomization

The contaminated droplets laden mucosalivary fluid and microbiome can be ejected from the patient's oral cavity during the dental atomization procedures. Owing to the limited studies focusing on dental spray dynamics and infection, the research aims to couple the particle image velocimetry and large eddy simulation to unravel the temporal evolution of multi-phase turbulent cloud, the droplet residence times, and the inhalation risk. The results indicate that dental-contaminated droplets, with a maximum size of 72.6μm, can escape from the core region (30°) of the dental spray under the surrounding air entrainment. The dehydrated droplet nuclei and small droplets can aggregate to form multi-phase turbulent clouds and move upward. The long residence time for aerosol particles of 10μm and 20μm indicates the necessity of instituting the fallow time between the subsequent appointments. The different operating postures can induce discrepancies in the particle inhalation mass, and the infection risk of a standing dentist is about 1.12 times higher than that of a sitting one. The significance of the present study lies in the promotion of evidence-based guidelines in surgery environments, further providing a scientific basis for future research in healthcare buildings.