|
Introduction. Professional toothcleaning with ultrasonic scaler produces microbial aerosols. These microorganisms come from dental unit waterlines (DUWLs) –thus potentially including opportunistic pathogens, or from patients –thus potentially including human pathogens.
Aim To investigate the association between levels and quality of contamination of air samples and DUWLs during professional toothcleaning, thus providing information regarding the nature of air contamination produced by ultrasonic scaler use.
Material and methods. Before treating the first patient of the day, 100 mL of water was aseptically collected from the DUWL designated for the ultrasonic scaler, water was not disinfected or flushed. Aliquots
were plated on Plate Count Agar to determine total viable flora (TVF) and Charcoal-Yeast Extract Agar supplemented with a Growth Supplement to determine Legionella. Two sets of settle plates were placed on
the tray in front of the patient, one before and another during patient treatment to determine TVF and Legionella. The association between TVF and Legionella levels and prevalence in DUWLs and in air samples
was assessed using correlation coefficients.
Results 82 testing occasions were performed. The mean TVF levels in DUWLs and air were 21.2 (95% confidence interval, 95CI, 13.8-32.6) CFU/mL and 12.4 (95CI, 9.7-15.8) CFU/plate/h, respectively. The
mean Legionella detection rates were 1.2% (DUWLs) and 0% (air). Correlations between air and water TVF and Legionella were not significant.
Conclusion. Air contamination during ultrasonic scaler use was frequent and high, but it was not associated with DUWL contamination, suggesting that airborne microorganisms could come from patients and
be potentially pathogens for humans.
Key words: dental unit waterline, airborne infection, Legionella, environment, infection control
|