compliance
Dental Unit Waterline Treatment
Avoiding Risk with Compliance
by Ilene A. Russo and Dwight Shreve
To quote writer and motivational
speaker Denis Waitley, “Life is
inherently risky. There is only one
big risk you should avoid at all
costs, and that is the risk of doing
nothing.” While on the surface it
can be seemingly dramatic to
apply this philosophy to dental
unit waterline treatment,
unfortunately, the inherent risks of
untreated dental unit waterlines
for both the well-being of patients
and the reputation of a dental
practice is a documented reality.
Devastating repercussions
In 2011, a fatal case of an otherwise
healthy, 82-year-old woman who devel-
oped Legionnaire’s disease after a dental
visit 1 was reported. In 2015, 20 children
who had undergone pulpotomies in the
same dental clinic were admitted to hos-
pitals in Georgia with infections caused
by Mycobacterium abscessus. The CDC
determined that the source of bacterial
contamination was untreated DUWLs
with biofilm that had become colonized
with M. abscessus. 2 In 2016, at least 50
children were hospitalized due to
chronic infections after receiving treat-
ment at an Anaheim, CA pediatric dental
clinic. Following an investigation by the
California state department of health,
the cause was confirmed to be related to
contaminated dental unit water with
Mycobacterium. 3
Although the topic of dental unit water-
line contamination was first reported
over five decades ago 4 , these incidents
bring to light the need for continued
awareness, education and conversation
around the subject.
12 HOUSTON DENTISTRY | www.houstondentistrymagazine.com
The causes of contamination
Research has shown microbial counts
can reach >200,000 CFU/mL within
five days after installation of new dental
unit water-lines 3 . Contamination levels
of up to 1 million CFU/mL of dental unit
water have been documented. 5 These
counts can occur because the narrow
hollow bore design of the tubing pro-
motes water stagnation and bacterial
accumulation. 6 Warming dental unit
water with the intent of improving
patient comfort can also augment
biofilm formation. Left untreated, the
biofilm can form along the walls of the
water line and can build up over time.
Compliance and prevention
According to CDC Dental Unit
Waterlines, Biofilm, and Water
Quality: General Recommendations 7
• Use water that meets EPA regulatory
standards for drinking water (i.e., <500
CFU/mL of heterotrophic water bacte-
ria) for routine dental treatment output
water.