Aerosols generated by high-speed handpiece and ultrasonic unit during endodontic coronal access alluding to the COVID-19 pandemic

Abstract

To investigate the dispersion and contamination of aerosols generated during coronal access performed by high-speed handpiece and ultrasonic device. To measure the aerosol dispersion, a red dye or an Enterococcus faecalis culture broth inside the bottle of the water system of the dental and ultrasonic unit were used. Bovine extracted teeth were allocated in six groups according to the coronal access: G1: diamond bur in high-speed handpiece (HS) with aspiration (A); G2: ultrasonic (US) inserts with aspiration; G3: combined coronal access with HS and US with aspiration; and G4, G5, and G6 were performed without aspiration (WA). The distance reached by the aerosol with the dye was measured in centimeters, and for environment contamination, agar-plates were arranged at standardized distances for counting colony-forming units (CFU/mL). The ANOVA followed by the Tukey tests were applied (α = 0.05). The coronal access with HS generated higher aerosol dispersion and contamination, even with simultaneous A (P < 0.05), while US generated less aerosol even WA (P < 0.05). The aspiration did not reduce the aerosol statistically. HS is a great source of aerosols in dental clinic during the coronal access and the use of US device should be encouraged.

Figure 1

(A) The 1014 diamond bur connected to a high speed handpiece to access incisors; (B) a representative image of direction of access surgery performed with diamond bur; (C) the E6D ultrasonic insert; (D) a representative image of direction of access surgery performed with E6D ultrasonic insert; (E) the E7D ultrasonic insert; (F) a representative image of access cavity refining moment; (G) the ultrasonic insert water system arrangement; (H) the aspiration sucker device employed in the experiments.

Figure 2

Positioning the BHI agar plates at distances of 60, 120, and 180 cm from the coronal access point and three additional plates, one on the right side at 60 cm, one on the left side at 1 m and other behind the operator at a distance of 1 m.

Figure 3

(A) Measurement of the distance in centimeters reached by the aerosol produced by introducing red dye to the AR and US water system; (B) Bacterial growth (CFU/mL) produced by the aerosol by introducing the inoculum into the AR and US water bottles.