Characterization of occupational exposure to airborne particles and bioaerosols in dental clinics

Abstract

Occupational exposure to airborne particles and bioaerosols in dental clinics is a potential hazard to dental health workers. Current studies on airborne particles and bioaerosols in dental clinics are limited and methodologically diverse, leaving gaps in the understanding of airborne particles in real-life dental settings. The aim of the study was to investigate the size, concentration, and composition of particles produced during dental procedures, and determine the exposure levels of dental personnel to respirable particles and bioaerosols in dental clinical environments with different characteristics. The study included two conventional dentist offices and one specialty clinic. The number concentration and size distribution of particles released during different dental procedures were monitored in real-time in dental procedure rooms. Personal samplers were used in parallel to collect the respirable and inhalable particle fractions. Total bacterial and total fungal DNA concentrations were quantified in the inhalable particle fraction by droplet digital polymerase chain reaction. Particle morphology and chemical composition were analyzed using scanning electron microscopy. The highest geometric mean value of the respirable particle mass concentration (0.06 mg/m3) was below the Norwegian occupational exposure limit for respirable dust of 5 mg/m3. Real-time sampling indicated that particle number concentrations were elevated during working hours in two clinics, with peak levels observed in one clinic coinciding with air polishing activities. The results also showed significant variations in bacterial and fungal DNA concentration levels (P < 0.0001). Many collected particles originated from powders used in dental treatments. Despite low respirable particle mass concentrations, increased levels of ultrafine particles during dental procedures highlight potential health risks to dental professionals. These findings also underscore the importance of advanced ventilation and safety measures to mitigate occupational exposure in dental environments.

Keywords: aerosol; bacteria; dental environment; dental treatment; fungi; microorganisms; respirable particles; work exposure.

Fig. 1.

Particle size distribution represented by electrical mobility diameter in the size range of 16.8 to 593 nm (d_mob) measured by SMPS in three dental clinics during working hours. Background levels are derived from days when the clinics were closed. Particle number concentration is shown on the y-axis.

Fig. 2.

Time series of a) the total number concentration for particles in the size range of 16.8 to 593 nm (d_mob) measured by SMPS, and b) number concentration of particles with size of d_ae = 1.04 µm measured with APS, during representative working days and background periods (weekends) among three dental clinics. Abbreviations of the dental treatment procedures; USS, ultrasonic scaling; AF, air polishing with air flow powder; CFR*, polishing of composite filing restoration; CFR#, drilling of composite filling restoration; CR, crown preparation; EX, examination; OT, orthodontic treatment; PP, polishing with pumice powder; SB, sandblasting with Al₂O₃; TX, tooth extraction.