by Mary Govoni, CDA, RDA, RDH, MBA
Infection control in dentistry is in the news again. As many media outlets reported recently, an 82-year-old woman in Italy died from Legionnaires’ disease as a result of exposure to the Legionella bacteria during dental treatment.
The woman reported leaving her house only to visit the dentist during what would have been the incubation period for her infection, between two and 10 days. The water in the woman’s house and in the dental office was tested for possible contamination. Water taken from the dental office taps and the high-speed handpieces tested positive for Legionella pneumophila, the causative agent for Legionnaires’ disease, while the water from the woman’s house did not test positive.
The conclusion of the investigators in this incident is that “aerosolized water from high-speed turbine instruments was most likely the source of the infection.”
Could it happen in U.S. dental practices? The answer is yes. This is why, after much research, the Centers for Disease Control and Prevention included recommendations for dental unit water quality in its Infection Control for Dental Health-Care Settings in 2003.
The guidelines state that “water used as a coolant/irrigant for nonsurgical dental procedures should be as low as reasonably achievable and, at a minimum, ≤500 CFU/mL (colony forming units), the regulatory standard for safe drinking water established by EPA (Environmental Protection Agency) and APHA (American Public Health Association)/AWWA (American Water Works Association).”
It should be noted that sterile water or sterile saline must be used for surgical procedures.
The CDC further states that research demonstrated that the microbial counts (CFU/s) in untreated or unfiltered water in dental units can be as high as 200,000 CFUs. These microbes may include Legionella, nontuberculosis Mycobacterium, and Pseudomonas aeruginosa, among others. Although the presence of these microorganisms is not believed to pose a threat to healthy people/patients, those who may be immune compromised, immune suppressed, or who suffer from chronic illness may be affected.
This case serves as a reminder of the need to follow current standards of care for patient safety. These standards are the 2003 CDC Guidelines. The case also reminds us that we must have an established protocol for meeting the water safety standards. The protocols should include:
- Flushing waterlines at the beginning of each day and between patient treatments
- Using water filtration systems or waterline cleaners and disinfectants to reduce microbial counts and prevent buildup of biofilm
- Testing water to monitor microbial counts
There are several types of systems that can be used to provide appropriate water quality for dental units. There are point-of-entry filter systems, such as the Sterisil system, which uses reverse osmosis, deionization, and ultraviolet radiation to reduce the microbial counts to all units in a facility. In addition, point-of-use systems, such as the Sterisil Straw and the DentaPure Cartridge system, can be installed on individual dental units.
These systems include an independent water supply bottle, with a cartridge that continuously releases an antimicrobial agent to prevent excessive biofilm buildup. It is important to note that prior to using any of these systems, a shock treatment must be used to reduce the biofilm that is built up in the waterlines. This treatment must be repeated at intervals recommended by the manufacturer.
For dental units that have independent water supply systems, there are many products that can be used to clean the waterlines. Some products, such as ICX from A-dec, Citrisil from Sterisil, BluTab from ProEdge Dental Products, and VistaClean from Hu-Friedy are continuous release formulas that are added to the water bottle each time it is filled.
Other products, such as Sterilex Liquid or Powder, Lines from Micrylium Professional Disinfection, and Mint-A-Kleen from Anodia Systems are used weekly and left in the waterlines overnight and flushed out prior to treating patients. The CDC also recommends monitoring or testing the quality of dental units periodically. A resource for water testing is ProEdge Dental Products.
In light of the recent incident in Italy, it is a good idea to review your waterline protocol, update it if necessary, and to test the water from your dental units if you have not done so. Patient safety is of utmost importance, and it’s also good business!
References available from author upon request.
Mary Govoni, CDA, RDA, RDH, MBA, is the owner of Clinical Dynamics, a consulting company based in Michigan. She is a member of the Organization for Safety, Asepsis and Prevention. She can be contacted at [email protected].
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