Distribution characteristics of microbial aerosols and optimization of protective methods during ultrasonic scaling procedure

Abstract

This study aimed to explore microbial aerosol distribution characteristics in the dental clinic during ultrasonic scaling and evaluate the effects of three different interventions on aerosol distribution and protective effects. For twenty minutes, ultrasonic scaling was carried out in a standardized operatory room. A blank control group and three intervention groups were created: high-volume evacuator (HVE), plasma purification (PP), and fenestrated ventilation (VT). The mass concentration of PM1.0, PM2.5, and PM10.0 aerosol particles was tracked in real time, and colony counts were calculated using air deposition. After ultrasonic scaling, there was a significant increase in aerosol dispersion of various particle sizes and distribution within a 1.5-m radius of the core area (P < 0.05). The number of colonies in each group varied over time at 0.5 and 1.0 m from the patient's head, but there was no significant difference at 1.5 m (P > 0.05). The PP group demonstrated the greatest decrease in aerosol mass concentration difference. The VT group initially had the lowest aerosol mass concentration difference, but with a slight decrease. The aerosol mass concentration difference between the HVE groups grew with distance. Traditional ultrasonic scaling poses a risk of aerosol contamination during and after treatment. The operatory room's air can be efficiently purified by plasma purification, which maintains lower levels of aerosol particle size than other groups. Microbial aerosols created by ultrasonic scaling can be quickly reduced by ventilation. At close range, the high-volume evacuator can lower the risk of infection while the benefit diminishes as the distance increases.Trial registration: This study was registered on the website of China Clinical Trial Registration Center (ChiCTR2400090751) (12/10/2024).

Keywords: Aerosol; High-volume evacuator; Plasma purification; Ultrasonic scaling.

Fig. 1

Standardized oral simulation operatory room. (A) Schematic diagram of standardized oral simulation operatory room and sampling sites. (B) Actual layout of the oral operatory room.

Fig. 2

Aerosol distribution of control group. Dynamic distribution of aerosol mass concentration of PM1.0 (A), PM2.5 (B) and PM10 (C).

Fig. 3

Plot of changes in the number of colonies at different sites in the control group. Changes in the number of colonies at 0.5 m (A), 1 m (B) and 1.5 m (C) sites in different orientations. Variation in the number of colonies at different distances from the left (D), right (E) and middle (F) sites. The colors indicate that the differences between the groups with corresponding colors are statistically significant. (* means p < 0.05, ** means p < 0.001, *** means p < 0.0001).

Fig. 4

Distribution of Petri dish colonies sampled after the start of scaling at the 0.5 m site of the 3 sites (A). Changes in the distribution of colonies at 0.5 m (B), 1.0 m (C),1.5 m (D) and both shoulders of the doctor (E). (* means p < 0.05, ** means p < 0.001, *** means p < 0.0001).

Fig. 5

Variation of aerosol mass concentration at different particle sizes at various sites. Dynamic distribution of aerosol mass concentration of PM 1.0 (A), PM 2.5 (D) and PM 10.0 (G) at 0.5 m in different groups. Dynamic distribution of aerosol mass concentration of PM 1.0 (B), PM 2.5 (E) and PM 10.0 (H) at 1.0 m in different groups. Dynamic distribution of aerosol mass concentration of PM 1.0 (C), PM 2.5 (F) and PM 10.0 (I) at 1.5 m in different groups.