Aerosol exposure of staff during dental treatments: a model study

BACKGROUND: Due to exposure to potentially infectious aerosols during treatments, the dental personnel is considered being at high risk for aerosol transmitted diseases like COVID-19. The aim of this study was to evaluate aerosol exposure during different dental treatments as well as the efficacy of dental suction to reduce aerosol spreading. METHODS: Dental powder-jet (PJ; Air-Flow(®)), a water-cooled dental handpiece with a diamond bur (HP) and water-cooled ultrasonic scaling (US) were used in a simulation head, mounted on a dental unit in various treatment settings. The influence of the use of a small saliva ejector (SE) and high-volume suction (HVS) was evaluated. As a proxy of aerosols, air-born particles (PM10) were detected using a Laser Spectrometer in 30 cm distance from the mouth. As control, background particle counts (BC) were measured before and after experiments. RESULTS: With only SE, integrated aerosol levels [median (Q25/Q75) µg/m(3) s] for PJ [91,246 (58,213/118,386) µg/m(3) s, p < 0.001, ANOVA] were significantly increased compared to BC [7243 (6501/8407) µg/m(3) s], whilst HP [11,119 (7190/17,234) µg/m(3) s, p > 0.05] and US [6558 (6002/7066) µg/m(3) s; p > 0.05] did not increase aerosol levels significantly. The use of HVS significantly decreased aerosol exposure for PJ [37,170 (29,634/51,719) µg/m(3) s; p < 0.01] and HP [5476 (5066/5638) µg/m(3) s; p < 0.001] compared to SE only, even reaching lower particle counts than BC levels for HP usage (p < 0.001). CONCLUSIONS: To reduce the exposure to potentially infectious aerosols, HVS should be used during aerosol-forming dental treatments.