Objectives: This study characterized respirable particles (0.5 to 10 µm), and bioaerosols generated during simulated clinical procedures in an operatory setting. Method: The particulate aerosols were generated by a high-speed hand piece with (1) #330 bur for a Class I cavity preparation in a posterior tooth, (2) 7901 bur for composite finishing and polishing and (3) diamond bur for anterior veneer preparation. Bioaerosols were generated by a high-speed hand piece with (1) #330 bur for Class I cavity preparation and (2) ultrasonic scaling. 1 mL of Micrococcus luteus (ML) (>106 viable cells/mL) was used as an indicator organism. Procedures were done for 5 minutes with high volume evacuation (HVE) and water spray. Particle aerosols were collected using filters and bioaerosols were collected with a cascade impactor and settling plates placed 12”-30” from the source. Particle size distributions and concentrations were measured and impactor and settling plates were examined for microbial growth. Results: The respirable particle concentrations (µg/m3) were:
|
Procedure |
0.5 µm |
0.7 µm |
1.0 µm |
2.0 µm |
5.0 µm |
10.0 µm |
Total |
|
Tooth Cutting |
0.0125 |
0.0592 |
0.2689 |
0.5582 |
0.6532 |
1.3348 |
2.8868 |
|
Comp Finish |
0.0046 |
0.0184 |
0.0703 |
0.1644 |
0.2709 |
0.5542 |
1.0826 |
|
Veneer Prep |
0.0105 |
0.0502 |
0.2168 |
0.4475 |
0.2944 |
0.5245 |
1.5439 |
Particle aerosols generated are well below the USEPA Air Quality Standards of 150 µg/m3 for PM10. Substantial ML growth was observed on settling plates affixed to the dentist’s chest. Little to no ML growth was found on settling plates distributed at other locations. Conclusions: HVE and water spray reduce the concentration of particle aerosols to less than the USEPA standard for PM10. No bioaerosols were detected beyond the closest plates.