By Lee Slaton, Vice President of Healthcare; Smart Training

This month, we’ll address a serious issue that every practice using dental water units should be aware of.
And while we’re at it, we’ll include a few related acronyms of particular importance to you—with a focus on DUWL and OSAP.


Most dental chairs these days have dental unit waterlines (DUWL), as opposed to water plumbed from public drinking water. Having dental unit waterlines gives a clinician the ability to have greater control over the quality of the water delivered to a patient’s mouth.

It also presents opportunities for water quality to worsen, if the water unit’s IFU (instructions for use) aren’t followed.


The Organization for Safety, Asepsis and Prevention (OSAP) and the Centers for Disease Control and Prevention (CDC) conducted quite a bit of research on the subject, and developed recommendations to ensure the quality of the water delivered to a patient’s mouth is acceptable.1

By the way, you should be familiar with OSAP—a non-profit organization and growing community of clinicians, educators, researchers, and industry representatives advocating safe and infection-free delivery of oral healthcare.

OSAP focuses on strategies to improve compliance with safe practices, and on building a strong network of recognized infection-control experts.

I suggest any clinician interested in improving his or her practice’s SOPs (standard operating procedures) regarding patient safety consider attending an OSAP Boot Camp. The boot camps are multi-day intensive courses lead by clinicians and research leaders in the field, where best practices and infection control issues are reviewed and discussed in detail. Several Smart Training compliance advisors have attended.

What’s considered safe (potable) drinking water?

For drinking water to be considered safe, test results show it should contain below 500 CFUs. (I know, another acronym). CFU stands for colony-forming unit, a number that basically tells us how much bacteria is in the water.

What results have you seen after testing water quality in dental water units?

Smart Training compliance advisors have personally witnessed dental water units with water quality test results of over 50,000 CFUs. Yep, you read that correctly. For you non-mathematicians out there, that means the water contained 100 times more bacteria than what’s considered safe for drinking water.

“But I use distilled (or treated) water.”

A typical question we hear from clinicians is, “How can the water be considered unsafe? I use (insert distilled water or treated water) in my dental water units.”

We can distill the answer down to one word: biofilm.

Biofilm is slime that builds up in the lines between the dental water unit and point of delivery, such as the air/water syringe. This film can build up quickly, and is hard to remove without proper treatment. While the water quality in the dental water unit itself can be perfectly safe, the quality of the water at the delivery point can be just plain nasty.

(If you live in Houston, you might remember Marvin Zindler, the TV consumer affairs reporter who railed about restaurant inspections that denoted “slime in the ice machine!” If Marvin did practice reviews instead of restaurant reviews, he might have gone on about “biofilm in the dental unit water lines!”)

How do I resolve this problem?

The solution isn’t complicated. Water in the dental water unit should be treated.

But what most clinicians miss is that most water treatment IFUs state that the dental unit waterlines should also be shocked periodically. (Read your dental water unit IFU!)

Think of how swimming pools are maintained. There’s a certain level of chlorine (the usual method of maintaining safe water quality) that’s maintained constantly, but periodically the pool must be shocked.

Shocking dental unit waterlines is really the only way to remove biofilm, and this must be addressed periodically in order to deliver safe water to your patients’ mouths.

How do I know my efforts to maintain water quality are working?

There’s only one sure-fire way: test your water periodically!

How often should you test? The CDC punted on this issue, and referred users to the dental water unit manufacturer’s recommendations. But those recommendations are all over the place.

No matter the recommended frequency of testing, the obvious place to begin is to start testing now. Test each operatory, and see where it’s at.

If you’ve never tested before, and you’re not treating your water and shocking the lines periodically, you’re most likely in for a scare.

And if you think this is a case of the boy crying wolf, consider the following synopsis of an OSAP presentation.2

Awareness of water contamination as a potential source of infection transmission has increased in recent years. Despite attempts to control microbial accumulation, waterborne bacteria have been responsible for recent infection transmissions.

For example, an outbreak of Non-tuberculous Mycobacterium (Mycobacterium abscessus) due to contaminated water occurred in Atlanta in 2015. In this incident, a number of pre-school and school-aged children were infected and experienced facial swelling, cervical lymphadenopathy, osteomyelitis, oral lesions and pulmonary nodules.

State epidemiologists identified a dental clinic as the source of the outbreak.

If you’re not treating the water in your dental water units—even if you’re using distilled water:

  • Contact the company you purchase supplies from for a recommendation on treatment solutions.
  • Follow the IFU for the product you choose.
  • Test your water.

The continued good health of your patients—especially those who have compromised immune systems—is in your hands.

1. “Follow CDC Guidelines”; (Article no longer available.) For similar content, see Best practices for dental unit waterline management.
2. “Dental Unit Waterlines—Lessons Learned from a GA Outbreak”; (Article no longer available.)

Smart Training’s OSHA compliance advisors and certified HIPAA professionals help practices fulfill compliance requirements. TDA members receive discounts when they mention “TDA Perks.”