Dental Waterline Infection Concerns

Dental Waterline Contaminants

The term "dental waterline" refers to the extremely small-diameter, flexible tubing that delivers water to dental handpieces and water syringes which ultimately deliver water into the mouths of dental patients. Unfortunately, due to their small lumen diameters, they are prone to the buildup of biofilm on their walls. That biofilm has been cultured and determined to contain many oral microorganisms:

• Streptococcus
• Actinomyces
• Staphylococcus
• Veilonella
• Caulobacter
• Candida

The American Public Health Association and the American Water Works Association have adopted a standard for drinking water of no more than 500 Colony Forming Units (CFU)/mL. Untreated dental handpieces deliver water at levels of 10,000 CFU/mL, and the smallest-diameter untreated dental waterlines have been measured at 400,000 CFU/mL. 

Dental Waterline Mechanics

The problem with biofilm buildup inside small-diameter dental waterlines is attributable to the characteristics of water flow through increasingly smaller diameter tubes.The waterlines inside a dental unit are a series of progressively smaller diameter delivery lines. The mechanics of this presents a problem with laminar flow inside the waterlines. As line diameter decreases, current flow at the periphery of the tube decreases dramatically, until in the smallest-diameter tubing the water at the periphery of the tube is practically not moving, or stagnant; the perfect environment for pathogenic biofilm development.

Dental Waterline Testing and Treatment

The Centers for Disease Control (CDC) and other healthcare authorities recommend that dental units have an isolated water source that can be monitored for purity. The water held by this system should also be treated to prevent contamination and infection. The CDC recently issued a Health Alert after serious post-operative infections were discovered in several pediatric dental patients following pulpotomies. The CDC issued the following safety recommendations:

• Dental waterlines should meet EPA minimal standards for drinking water: less than 500 CFU.mL
• Waterline monitoring for contamination should be performed on a regular basis
• Consider irrigating with sterile water and/or an antimicrobial solution
• Utilize water bottle delivery systems that are independent of potential contamination
• Treat water in independent bottle delivery systems with anti-microbial agents

For additional information reference our CE course on Dental Waterline Safety 2022