How Clean Dental Unit Waterlines Prevent the Spread of Aerosol Transmissible Diseases

June 30, 2020

As dental offices begin reopening after the COVID-19 outbreak, there is an elevated level of concern about the transmission of diseases, with the main culprit being aerosol generating procedures (AVP). With that said, dental unit waterlines can also contribute to the spread of infection. This article seeks to alleviate the concerns of dentists and patients alike by addressing waterline safety in the dental office.

How Do Pathogens Make It to Dental Waterlines?

Dental operative units supply waterpower for handpieces and other dental accessories. The unit’s waterlines, which are made either from polymer or silicone rubber tubing, provide the water needed for irrigation, cooling and flushing. In turn, the water comes from either the municipal water facility or a closed bottle water system.

Since the water source is not sterile enough to meet industry standards, bacteria or pathogens can survive in the water, making it a breeding ground for infection. The pathogens attach themselves to the side of the dental unit waterlines, creating biofilms or accumulations in the waterline’s interior. These biofilms also contain trace amounts of nutrients that promote the multiplication and growth of harmful microorganisms.

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How are Dental Waterlines Connected to Aerosol Transmissible Diseases?

Ultrasonic scalers and other handpieces make use of these waterlines. These tools need compressed air and water to work effectively, and this results in the production of aerosols in the dental office.

Apart from the patient’s blood and saliva, the aerosols contain the by-products of the biofilm. These can either land on individuals in the operatory or remain suspended in the air. Thus, the aerosolized particles are a constant threat and can infect patients if not cleaned immediately by a dental aerosol reduction device.

Even if the COVID-19 virus is not present anywhere in the clinic, the pathogens from dental aerosol production may weaken the immune system, making the exposed individuals more likely to catch the virus in other places.

How to Maintain Clean Waterlines

In order to help stop the spread of COVID-19 and other diseases, dental offices must consult with the manufacturer of the dental unit before proceeding with maintenance.

  • Adhere to recommendations by the Center for Disease Control and Prevention (CDC) and the American Dental Association (ADA) to flush dental unit waterlines for several minutes every morning. Also, clinicians should flush the handpieces with air/water for 20-30 seconds between patients. Installing sterilized handpieces reduces the risk of cross-contamination
  • Install anti-retraction valves to stop oral fluids from invading waterlines
  • Test the water quality to see if it meets the standards of the Environmental Protection Agency for safe drinking water. Ideally, the water quality should be at <500 CFU/mL
  • Avoid using heated dental unit water since it tends to amplify the formation of biofilms
  • Use sterile solutions for surgical irrigations
  • Train oral healthcare workers on measures to decrease the risk of contamination in dental instruments
  • Teach staff to comply with the clinic’s chosen treatment approach
  • Be on the lookout for signs of biofilm formation, such as clogging of lines, cloudiness in the water or musty odor

Long Term Changes Practitioners Should Implement

For future infection-free waterline systems and continued aerosol reduction, dentists, dental assistants, and hygienists need to take the following steps:

1. Ensure that the sterile water system has received clearance from the Food and Drug Administration (FDA)
2. Consider purchasing options for improving dental unit water such as independent water reservoirs, draining and air purging regimens, and chemical treatment regimens to control biofilm production.

In the post COVID-19 world, having a tidy dental clinic is everything. Maintaining the dental unit waterlines will go a long way in mitigating the spread of disease.

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