Evaluating aerosol and splatter following dental procedures

Background Dental procedures often produce aerosol and splatter which are potentially high risk for spreading pathogens such as SARS-CoV-2; existing literature is limited. Objective To develop a robust, reliable and valid methodology to evaluate distribution and persistence of dental aerosol and splatter, including initial investigations evaluating clinical procedures. Methods Fluorescein dye was introduced into irrigation reservoirs of dental equipment. High-speed air-turbine, ultrasonic scaler and 3-in-1 spray were used on a mannequin. Procedures were in triplicate. Filter papers were placed in the immediate environment. The impact of dental suction and assistant presence were also evaluated. Fluorescein samples were analysed by photographic examination with image analysis, and spectrofluorometric analysis. Statistics were descriptive with Pearson9s correlation for comparison of methods. Results All procedures were aerosol and splatter generating. Contamination was highest closest to the source, remaining high to 1-1.5 m. Contamination was detectable at the maximum distance measured (4 m) for high-speed air-turbine with maximum relative fluorescence units (RFU) being: 46,091 at 0.5 m, 3,541 at 1.0 m, and 1,695 at 4 m. There was uneven spatial distribution with highest levels of contamination opposite the operator. Very low levels of contamination (≤0.1% of original) were detected at 30- and 60-minutes post procedure. Suction reduced contamination levels by 67-75% between 0.5-1.5 m. Mannequin and operator were heavily contaminated. The two analytic methods showed good correlation (r=0.930, n=244, p=.000). Conclusion Dental procedures have potential to deposit aerosol and splatter at some distances from source, being effectively cleared by 30 minutes in our setting.