Characterization and mitigation of aerosols and spatters from ultrasonic scalers

Ou, Qisheng; Placucci, Rafael Grazzini; Danielson, Judy; Anderson, Gary; Olin, Paul; Jardine, Paul; Madden, John; Yuan, Qinghui; Grafe, Timothy H; Shao, Siyao; Hong, Jiarong; Pui, David Y H

BACKGROUND: Dental procedures often produce aerosols and spatter, which have the potential to transmit pathogens such as severe acute respiratory syndrome coronavirus 2. The existing literature is limited. METHODS: Aerosols and spatter were generated from an ultrasonic scaling procedure on a dental manikin and characterized via 2 optical imaging methods: digital inline holography and laser sheet imaging. Capture efficiencies of various aerosol mitigation devices were evaluated and compared. RESULTS: The ultrasonic scaling procedure generated a wide size range of aerosols (up to a few hundred µm) and occasional large spatter, which emit at low velocity (mostly < 3 m/s). Use of a saliva ejector and high-volume evacuator (HVE) resulted in overall reductions of 63% and 88%, respectively, whereas 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 spatter emission. The use of HVE generally requires an additional person to assist a dental hygienist, whereas an ELE can be operated hands free when a dental hygienist is performing ultrasonic scaling and other operations. PRACTICAL IMPLICATIONS: An ELE aids in the reduction of aerosols and spatters during ultrasonic scaling procedures, potentially reducing transmission of oral or respiratory pathogens like severe acute respiratory syndrome coronavirus 2. Position and airflow of the device are important to effective aerosol mitigation.