Legionnaires’ disease in dental offices: quantifying aerosol risks to dental workers and patients

Published on 01/11/2022 | by Waterline Admin

Hamilton KA, Kuppravalli A, Heida A, Joshi S, Haas CN, Verhougstraete M, Gerrity D.

J Occup Environ Hyg. 2021 Jun 23:1-21. doi: 10.1080/15459624.2021.1939878. Epub ahead of print. PMID: 34161202.

 

Highlights

  • Dental offices pose a potential risk for inhalation or aspiration of pneumophila due to the high surface area to volume ratio of dental unit water lines (DUWL)
  • DUWL are conducive to biofilm growth and high-pressure water devices (e.g., ultrasonic scalers) produce fine aerosols within the breathing zone.
  • pneumophila occurs in DUWL, but associated human health risks have not been assessed.
  • Probabilities of infection were assessed on a per-exposure and annual basis.
    • Following instrument purge (i.e., flush) and with ventilation rate of 1.2 air changes/hr, the median per-exposure probability of infection for dental hygienists and patients exceeded a 1-in-10,000 infection risk benchmark.
    • Per-exposure risks for workers during a purge and annual risks for workers wearing N95 masks did not exceed the benchmark.
    • Increasing air change rates in the treatment room from 1.2 to 10 would achieve an ∼85% risk reduction, while wearing N95 respirators would reduce risks by ∼95%.
  • Concentration of pneumophila in DUWL was a dominant parameter in the model and driver of risk.

 

LINK TO PAPER – CLICK HERE

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