# Splatters and Aerosols Contamination in Dental Aerosol Generating Procedures
###### Abstract  
Dental aerosol-generating procedures produce a large amount of splatters and aerosols that create a major concern for airborne disease transmission, such as COVID-19. This study established a method to visualise splatter and aerosol contamination by common dental instrumentation, namely ultrasonic scaling, air-water spray, high-speed and low-speed handpieces. Mock dental procedures were performed on a mannequin model, containing teeth in a typodent and a phantom head, using irrigation water containing fluorescein dye as a tracer. Filter papers were placed in 10 different locations to collect splatters and aerosols, at distances ranging from 20 to 120 cm from the source. All four types of dental equipment produced contamination from splatters and aerosols. At 120 cm away from the source, the high-speed handpiece generated the greatest amount and size (656 \(\pm\) 551 \(\upmu\)m) of splatter particles, while the triplex syringe generated the largest amount of aerosols (particle size: 1.73 \(\pm\) 2.23 \(\upmu\)m). Of note, the low-speed handpiece produced the least amount and size (260 \(\pm\) 142 \(\upmu\)m) of splatter particles and the least amount of aerosols (particle size: 4.47 \(\pm\) 5.92 \(\upmu\)m) at 120 cm. All four dental AGPs produce contamination from droplets and aerosols, with different patterns of distribution. This simple model provides a method to test various preventive strategies to reduce risks from splatter and aerosols. d 2021 11 1  
particles, and these fall onto surfaces in the dental operator under the influence of gravity, following a ballistic trajectory from the point of origin. In contrast, droplets can remain suspended in the air until their water evaporates, and aerosols can remain suspended for several hours (depending on local air movement) and can travel for 1-3 m from their source [13]. Dental splatter, droplets and aerosols may contain pathogenic oral bacteria, nanoparticles [6; 14; 15; 16], as well as respiratory viruses (including adenoviruses, influenza viruses, and the SARS-CoV-2 coronavirus [6; 17]). Much greater attention has been focussed on dental aerosol-generating procedures (AGPs) because of the coronavirus disease 2019 outbreak (COVID-19), caused by the Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. In some cases, especially when people are in close proximity to one another, COVID-19 has been proven to spread through airborne transmission [18; 19]. The SARS-CoV-2 coronavirus can remain infectious in aerosols for extended periods, even when the water has evaporated, and particles that then settle onto surfaces can remain infectious for up to 72 h [20; 21]. The airborne transmission of SARS-CoV-2, via salivary bioaerosols, poses a significant danger to healthcare workers that operate close to the face and oral cavities, such as dental practitioners, and oral and maxillofacial surgeons, especially when carrying out AGPs [5; 19; 22]. It is of considerable interest to have a straightforward method to visualise and map the pattern of splatter/droplets/aerosols during AGPs. Past work has focussed mainly on the microbiological evaluation of bacteria contamination from aerosols and splatter following dental procedures, by counting aerobic bacteria colonies deposited onto agar plates positioned at various locations [23; 24]. Other studies have used fluorescent tracers (such as sodium fluorescein) to show in broad terms the distribution of ejected material [13; 25]. These methods have been used to show macro-spatial distributions of material produced by ultrasonic scalers [13], or other devices such as the high-speed air-turbine, or the triplex syringe [25]. To date, there is limited data that determined the distribution of aerosols and splatter at the microscale for the most commonly used devices, namely the ultrasonic scaler, triplex syringe, high-speed headpiece, and low-speed headpiece.