Studying the spatial flow characteristics of droplets induced by ultrasonic tooth-cleaning machines

The use of an ultrasonic scaler in the dental diagnosis and treatment process can produce a large number of droplets due to splashing, which can be transformed into droplet nuclei in the form of aerosols suspended in the air of the clinic, and droplets and aerosols may carry pathogenic microorganisms that pose a great threat to the health of clinical staff and patients. This paper takes a dental clinic as the research object and adopts experimental and numerical simulation methods to study the splashing droplet flow during ultrasonic dental cleaning surgery. It explored the similarities and differences in the spatial flow characteristics of droplets caused by different operation modes in the ultrasonic dental cleaning process. The results showed that the large droplets (particle size >100 μm) caused by the ultrasonic dental cleaning machine could be spread to the dangerous range of the patient's surroundings at 2.5 m. The droplets could be spattered to the patient's oral cavity at 1.5 m above the room, and the room was contaminated with a space of 17.5 m3. The droplets were concentrated, and the smaller droplets particles were more concentrated in the 0.75 m of the patient's oral cavity. The concentration of the small droplet particles (particle size 1–100 μm) of the splash height can be up to the clinic's ceiling in the air for a long time, and the contamination range can be expanded to the entire clinic. This study will provide strong guidance for developing microbial adsorption and elimination equipment for dental clinics and formulating new prevention and control opinions for dental clinics.