CDA Essentials 2019 • Volume 6 • Issue 6

39 Issue 6 | 2019 | S upporting Y our P ractice unused for varying lengths of time will need to be tested occasionally to determine appropriate frequency and duration of flushing. A tailored plan for each line is based on water quality readings and estimates of how long the disinfectant remains effective in that line (which may be more difficult to determine). For example, a waterline that remains unused for several hours during the day with a consistent test result of 20 CFU/ml will need to be tested at regular intervals (for example, after 1 hour, after 2 hours, after 4 hours) to determine how long water quality is maintained. 5. Use waterline disinfectants, including a disinfectant to “shock” or remove as much bioburden as possible. Water disinfection for DUWL is performed by including a suitable disinfectant in the water used for patient care. An ongoing water quality monitoring program ensures that quality is maintained in all lines, including ultrasonic scaler lines, and that reductions in water quality can be treated quickly and appropriately. There are two types of disinfectants used for DUWL: continuous and intermittent. i. Continuous Disinfectants As the name implies, continuous disinfectants are applied constantly to the water used for patient care. They must be safe for both patient consumption and routine use of dental materials according to the manufacturer’s intended use. Continuous disinfectants are supplied in various forms. They are available as tablets or liquids that can be added to the water reservoir (bottle), usually each time water is added. Or, continuous disinfectants can be installed in the waterline in the form of what manufacturers call “straws,” “filters” or “cannisters.” Prior to the installation of these inline disinfection systems, lines must be “shocked”—a term that describes intermittent disinfection to reduce existing biofilm. Without shock treatment, inline disinfection systems may not be able to manage the bioburden in the lines. Before making a choice as to what kind of continuous disinfection system to use in your office (tablets/liquids or inline), consider a key advantage of inline systems: human error is nearly eliminated. With tablets or liquids, there is the potential risk of human error. Although tablets or liquids are less expensive than inline systems, they require additional resources for maintenance, such as operator time, which should also be factored into cost estimates. ii. Intermittent Disinfectants When water quality testing demonstrates that continuous disinfection alone is inadequate for maintaining water quality, then intermittent disinfectants are a necessary adjunct. To use intermittent disinfectants, the material recommended by the manufacturer is placed into the water reservoir. All waterlines are then flushed until the disinfectant has filled the lines. Intermittent disinfectants are often coloured to provide a visual cue that the disinfectant is in the line. The intermittent disinfectant is then left in the lines according to the MIFUs. While the intermittent disinfectant is left in the lines, the water is neither safe nor potable and must not be used for patient care. The disinfectant is discarded from the water bottle, the bottle is cleaned and refilled with fresh water, and the lines are flushed copiously as per MIFUs. This method of using an intermittent disinfectant in the lines, leaving it for the required time, and then flushing it thoroughly from the lines, is called “shocking.” The protocol for shocking with intermittent disinfectant highlights a concern for DUWL that are directly plumbed to municipal water sources: shocking is not possible as there is no simple way to access the DUWL. In addition, water from a municipal supply cannot be used during boil water advisories. For these reasons, it is recommended that all dental units be plumbed independently—not directly to a municipal water supply. 6. Follow end-of-day procedures according to MIFUs. Some waterline disinfection systems require that the water bottle remain on the system. Others require that the water bottle be removed, the water discarded, and all waterlines run until dry. The water bottle is then cleaned and replaced but the lines remain dry when not in use. 7. Monitor water at source and in the DUWL. For critical procedures, use sterile water or sterile saline, administered with a sterile syringe. • Test both the source water and the unit water. Sample each line individually, including the ultrasonic scaler line through the ultrasonic scaler. Alternatively, the test can be performed by using an aggregate sample; for example, if there are five waterlines, 20% of the entire sample would be taken from each line. However, one risk of aggregate sampling is Infection Protection and Control at the Dental Office ev n