Hamilton KA, Kuppravalli A, Heida A, Joshi S, Haas CN, Verhougstraete M, Gerrity D. Legionnaires’ disease in dental offices: quantifying aerosol risks to dental workers and patients. J Occup Environ Hyg. 2021 Jun 23:1-21. doi: 10.1080/15459624.2021.1939878. Epub ahead of print. PMID: 34161202.

Published on 01/11/2022 | by Waterline Admin


  • 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.



Grime Scene

Grime Scene

Click the gallery image above to view our Grime Scenes!

Waterline Advertisement Disclaimer

In accordance with the law, the inclusion of advertising, logos or web site links on this web site does not constitute an endorsement by the WMSoc of the products or services so advertised.

Third party advertisements and links to other sites where goods or services are advertised are not endorsements or recommendations by WMSoc of the third party sites, goods or services.

WMSoc takes no responsibility for the content of the advertisments, promises made, or the quality/reliability of the products or services offered in all advertisements.
WMSoc shall have no liability for the accuracy of the information and cannot be held liable for any third-party claims or losses of any damages.

Product Spotlight

Cistermiser launches Vecta+ Sensor Tap Range

The Vecta+ Sensor Tap range are easy to install, as retrofit or new build installations. They help to improve hygiene and prevent the transfer of pathogens with no-touch controls. With an infrared tap, the water only runs while your hands are in range, so these taps reduce wasted water, increase efficiency, save energy and reduce costs, while maintaining reliability and high performance. For more information about these infrared taps, visit www.cistermiser.co.uk or call 0118 969 1611.

Velappity- Risk Assessment and Compliance Software

Velappity is a risk assessment and compliance solution that can reduce your reporting time by 50% and improve operational efficiency. Our forms module eliminates the drawbacks associated with paper-based reporting. You can easily create branded risk assessments and complex forms in a digital framework to complete inspections on-site, on any device. The integrated compliance module enables organisations to manage and report on all types of assets and complete inspection tests, raise non-compliances and report to clients, all within the app.

Effective Thermal Disinfection at POU

By using the readily available system temperature hot water supply (>60C), the patented ILTDU, In-Line Thermal Disinfection Unit, from Horne Engineering facilitates the only effective thermal disinfection of showers, taps, TMVs, their associated pipe-work feeds, ancillary fittings, mixed water deadleg and terminal outlet fitting. In conjunction with high velocity flushing, which shears excess biofilm from internal pipework surfaces (and represents 95% of the water system’s total bio-load) thus improving water quality, regular operation of the ILTDU further aids the risk-management of retrograde pathogens, e.g. opportunistic Pseudomonas Aeruginosa, Non-Tuberculous Mycobacteria and others. http://b.link/Pathogen-Control

HM&V Utilities Ltd – Helping you stay compliant

HM&V Utilities Ltd are a LCA Registered Water Hygiene and Utility Specialist based the South of the UK. We provide comprehensive packages to help clients stay compliant with their obligations under current legislation and law. From the initial Risk Assessment to corrective remedial actions, we have you covered. We are LCA registered and ISO9001 accredited to carry out Legionella Risk Assessments, Cleaning and Disinfection services as well as Sampling & Analytical Services.