Characterization and mitigation of aerosols and splatters from ultrasonic scalers

Abstract

Background: Dental procedures often produce aerosols and splatter which have the potential to transmit pathogens such as SARS-CoV-2. The existing literature is limited. Methods: Aerosols and splatter were generated from an ultrasonic scaling procedure on a dental mannequin and characterized by two optical imaging methods – digital inline holography (DIH) and laser sheet imaging (LSI). Capture efficiencies of various aerosol mitigation devices were evaluated and compared. Results: The ultrasonic scaling procedure generates a wide size range of aerosols up to a few hundred micrometers and occasional large splatter which emit at low velocity (mostly below 3 m/s). Use of a saliva ejector (SE) and high-volume evacuator (HVE) resulted in 63% and 88% of overall reduction respectively while an extraoral local extractor (ELE) resulted in a reduction of 96% at the nominal design flow setting. Conclusions: The study results showed that the use of ELE or HVE significantly reduced aerosol and splatter emission. The use of HVE generally requires an additional person to assist a hygienist, while an ELE can be operated hands-free when a dental hygienist is performing ultrasonic scaling and other operations. Practical Implications: An extraoral local extractor aids in the reduction of aerosols and splatters during ultrasonic scaling procedures, potentially reducing transmission of oral or respiratory pathogens, like SARS-CoV-2. Position and airflow of the device are important to effective aerosol mitigation.

The Efficacy of High-Volume Evacuators and Extraoral Vacuum Aspirators in Reducing Aerosol and Droplet in Ultrasonic Scaling Procedures during the COVID-19 Pandemic

“…5 17 EOVA is more effective when located 14 mm from the working zone rather than 18 mm. 21 However, studies on the effectiveness of HVE and EOVA are still limited and further studies on the design, power, and recommended instructions for using these devices are still needed.…”

An experimental approach to analyze aerosol and splatter formations due to a dental procedure

“…10. Note that Ou et al (2021) studied the splatter produced from an ultrasonic scaler using a similar (7)…”

“…They utilized an approach called laser sheet imaging (LSI) to capture the far field splatter in a 14 cm × 14 cm field of view. They also used an ultrasonic scaler in conjunction with different evacuation methods (Ou et al 2021) where they found the majority of the splatter produced from a scaling procedure on tooth #25 or #24 was less than 2 m/s (Ou et al 2021).…”

“…It is worth noting that the scaler used for the shadowgraphy analysis is slightly different in shape compared to the one used in the OFTV experiments, although our analysis showed that they both produce almost the same size of droplets and operate approximately in the same manner. Very recently, Ou et al (2021) used digital inline holography (DIH) to measure the droplet size within a splatter produced by an ultrasonic scaler positioned against different teeth. They determined that 99% of the droplets measured were in the range of 12 μm and 200 μm which is similar to our findings (Ou et al 2021).…”

“…Very recently, Ou et al (2021) used digital inline holography (DIH) to measure the droplet size within a splatter produced by an ultrasonic scaler positioned against different teeth. They determined that 99% of the droplets measured were in the range of 12 μm and 200 μm which is similar to our findings (Ou et al 2021). Han et al (2021) also positioned filter papers around mock dental procedures using ultrasonic scalers.…”