On October 31, 2022, the CDC released a Health Advisory regarding nontuberculous Mycobacteria (NTM) infections associated with contaminated dental unit waterlines and the need for dental health care personnel (DHCP) to follow established recommendations to ensure the safety of their patients. While the incidence of these infections is rare, there have been multiple documented cases of disease transmission from dental unit waterlines. These recent outbreaks of (NTM) infections reemphasize the great importance of maintaining and monitoring all dental unit waterlines to ensure the health and safety of all our patients.

It is important to remember that dental unit waterlines can promote bacterial growth and the development of biofilm, thus all dental unit waterlines must be treated regularly with chemical germicides. Untreated dental units cannot reliably produce water that meets drinking water standards (which is fewer than 500 CFU/mL of water of heterotrophic water bacteria). Even if your dental practice uses low microbial water (such as distilled or sterile water) to fill up a self-contained water bottle system, routine treatment of the waterlines with chemical germicides to eliminate bacterial contamination is necessary. 

The CDC Health Advisory contains recommendations and a list of resources for DHCP to obtain more information on keeping your dental equipment and patients safe. Some key recommendations include (please refer to the Health Advisory for the complete list):

• Use water that meets Environmental Protection Agency (EPA) regulatory standards for drinking water (i.e., ≤500 colony forming units (CFU)/mL of heterotrophic water bacteria) for all non-surgical dental treatment output water.
• Consult with the dental unit manufacturer for appropriate methods and equipment to maintain the quality of dental water.
• Follow recommendations for monitoring water quality provided by the manufacturer of the unit or waterline treatment product.
• Use sterile saline or sterile water as a coolant/irrigant for surgical procedures.
• Consider irrigating with a sterile and/or antimicrobial solution during all non-surgical pulpal therapy/endodontic procedures.
• Provide staff training on how to properly maintain and monitor dental water quality.
• Discharge water and air for a minimum of 20–30 seconds after each patient from any device connected to the dental water system that enters the patient’s mouth (e.g., handpieces, ultrasonic scalers, and air/water syringes).

In the unfortunate circumstance that a potential patient infection occurs, please notify your local health department and DHS immediately.