Greatest Practices for Dental Unit Water High quality | Dental An infection Prevention and Management
Why it matters
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). On October 31, 2022, CDC released a Health Advisory Notice to communicate the importance of following existing recommendations for maintaining and monitoring dental waterlines.
Background
Biofilm is a thin, slimy film of bacteria that sticks to moist surfaces. Dental unit waterlines have unique characteristics that make them prone to biofilm formation, including long, small-diameter tubing, low flow rates, and frequent periods of stagnation.
High numbers of common water bacteria can be found in untreated dental unit water systems, including Legionella, Pseudomonas aeruginosa, and nontuberculous Mycobacteria. These bacteria can cause serious, sometimes life-threating infections.
Contaminated water from dental units has been linked to outbreaks of Mycobacteria infections in children. Case reports also document infections with Mycobacteria and Legionella following endodontic procedures, third molar extractions, and general dental work. In these reported cases, water samples taken from the dental clinics demonstrated levels of bacteria much higher than the recommended levels and reported breakdowns in infection prevention procedures to maintain and monitor dental water quality. These reports highlight the need for training to improve understanding of the underlying principles of dental unit water quality maintenance and monitoring, recommended practices, and their implementation in dental settings.
Special considerations
For surgical procedures, sterile saline or sterile water should be used as a coolant or irrigant. Conventional dental units cannot reliably deliver sterile water even when equipped with independent water reservoirs containing low-microbial or sterile water because the water-bearing pathway cannot be reliably sterilized. Appropriate delivery devices should be used to deliver sterile water during surgery. Examples include bulb syringes; sterile, single-use disposable products; or sterile water delivery systems that bypass the dental unit by using sterile single-use disposable or sterilizable tubing.
Frequently asked questions
There are many commercial products and devices available to disinfect and maintain dental unit waterlines, including:
- Self-contained water systems (e.g., independent water reservoir) combined with chemical treatment (e.g., periodic or continuous chemical germicide treatment protocols).
- Systems designed for single-chair or entire-practice waterlines that condition or treat incoming water to remove or inactivate microorganisms.
- Combinations of these methods.
Available products to treat waterlines include tablet systems, continuous release straws and cartridges, initial and periodic shock treatments, and centralized systems. All products and systems must be used and maintained according to the manufacturer instructions for use (IFUs). If you have questions about the IFUs, contact the manufacturer of the treatment product or device that you are using.
The unit should be treated according to manufacturer IFU, and re-tested immediately after treatment. If a unit remains resistant to treatment over time, it may be necessary to replace waterlines or other water-bearing components.
