Safe Water, Safe Patients

Infection Control

Growing attention to the hazards of contaminated dental unit water has led more dental clinicians to take the necessary steps to protect their patients.

There are no shortcuts to obtaining compliant dental water. Without the right products and protocols, however, dental practices will not be able to meet the acceptable standard for water delivered to patients during non-surgical procedures.

What’s more, even though compliance with water safety standards in the United States has not been required by law, that is changing.

“A dental practice simply will not achieve compliance without effective, EPA-validated products used in accordance with the correct protocols,” says Jerod Mendolia, marketing assistant, Sterisil, Inc. “At Sterisil, our philosophy is embodied in the acronym, PPC: Products + protocols = compliance. We have applied this methodology with great success in various settings, from mid-sized five-chair clinics to Ivy League dental schools.” New technology is important, he adds. But unless clinicians are educated on the appropriate protocols and develop a conscientious attitude, “we are setting them up for failure.”

A serious business
Because dental water is used as an irrigant solution in conjunction with high-speed rotary handpieces, potentially contaminated aerosols and spatter can carry waterborne pathogens through the air, increasing the potential for infections. Unwanted health implications associated with contaminated dental unit coolants range from the exacerbation of existing asthma symptoms due to endotoxin exposure to complex bacterial infections, such as Legionnaires’ disease, according to the Organization for Safety and Asepsis Prevention (OSAP). In recent years, two high-profile cases have linked dental unit water to serious infections, notes Mendolia. The first incident occurred at Dentistry for Children in Jonesboro, Georgia. A second incident occurred at Children’s Dental Group in Anaheim, California. In both cases, Mycobacterium were isolated as the cause of infections in pediatric patients who received a pulpotomy procedure with contaminated dental unit water, he points out.

Although the Centers for Disease Control and Prevention (CDC) has recommended that water delivered to patients during non-surgical dental procedures meet Environmental Protection Agency (EPA) standards for drinking water (<500CFU), some question whether this is sufficient in a clinical environment. “In 1995, the American Dental Association challenged dental unit manufacturers to develop the equipment necessary to deliver effluent handpiece water with <200CFU,” says Mendolia. That standard has since been raised to the <500CFU/ml drinking water standard. “Currently, there are many products on the market validated to deliver levels of disinfection well below 200CFU. I don’t think it is unreasonable to expect dental professionals to meet this higher standard considering the number of products and protocols available with advertised effectiveness claims at =10CFU.”

The right solution
For many dental professionals, the importance of delivering safe water during patient treatment is clear. Navigating their options, however, can sometimes be tricky. There are several methods available for treating water, notes Mendolia, and clinicians must stay informed in order to best serve their patients. There are advantages and disadvantages to each.

There are many filter options capable of removing some level of microbial contaminants, but without the presence of a residual disinfectant, filtration alone is insufficient to consistently maintain and prevent microbial growth downstream from the filter, according to Mendolia. For best results, filtration should be paired with an ion exchange-based product for shock and residual disinfection. “Clinicians should steer clear of filtration methods that require water storage in a tank,” he says. “Unless the practice has something like a UV light after the tank, water storage can lead to incubation of existing bacteria in the tank to >500CFU. Most waterline treatment products will have some sort of disclaimer stating for use with potable water. So, contaminated storage tank water would be unsuitable for use with many chemical treatments based on this alone.

“Since the introduction of the independent bottle reservoir, chemical treatments have become a viable and convenient method for reducing effluent dental water microbes,” he continues. “When dental clinicians follow the instructions for use (IFUs), they can expect good results. However, when using municipal tap water, they must do so with caution. Municipal contaminants like chlorine and copper can interfere with the efficacy of some chemical treatments. The best regimens will always feature both shock and maintenance treatments that are compatible with one another. Whenever possible, clinicians should use distilled water in their bottle reservoirs for the best results.”

In theory, in-office distillers are a viable solution, notes Mendolia. However, they are often associated with water test failures. “The machinery of distilling demands regular cleaning and disinfection to ensure the water purity and microbial viability,” he explains. “Once water has been heated into a gas and condensed back into liquid, it no doubt will be above room temperature. This increases the likelihood you are incubating bacteria as it’s stored. Without a residual disinfectant or some sort of shock treatment prior to introduction to the chair, it’s unlikely the 500CFU drinking water standard will be met, and the practice risks violating the manufacturer’s labeling.

“Don’t get me wrong,” he says. “Distilled water is much better than municipal tap water in just about every way. But physically distilling water is not the most effective method. Deionized water is essentially the same thing, and the process by which it is created does not increase the bacterial content. It is for this reason, all Sterisil systems employ this technology as the final purification step. Now you have a very pure base water to which a  residual disinfectant can be introduced, with minimal interference from microbes or chemical contaminates.”

Pre-sterilized water is clean enough for any dental procedure, says Mendolia. “However, once it is introduced into a dental chair, it is unlikely to meet the <500CFU standard,” he points out. “Unless the dentist intends to irrigate with single-use pipettes or purchase a very expensive sterile water generator, this will not be a viable option.” And, the cost of purchasing sterile water makes this an unaffordable option for many dental practices, he adds.

Mendolia recommends that dental practices use their bottle reservoirs for their intended purpose. “The independent bottle reservoir was designed to isolate the dental unit from municipal tap water and provide a conduit through which antimicrobial treatments could be introduced,” he says. “Tap water is not suitable for the dental setting for many reasons, but particularly due to the infinite variability in water chemistry. If clinicians are using residual disinfectants to control microbes in a dental chair, these details matter. Distilled water will always save the dental practice a lot of headaches in the end, trust me.

“Dental practices should always consult with their dental unit manufacturers and their waterline treatment providers about water testing,” Mendolia continues. “Minimum standards for water testing should be followed whenever possible, even though they are recommendations rather than requirements. If the dental practice’s protocols are in line with these standards, it is off to great start.”

A passing water test verifies the absence of bacteria and validates the dental practice’s disinfection efforts, he points out. “According to OSAP, dental practices should be testing within 30 days of introducing a new product or new protocols, and then every 30 days thereafter,” he says. “The initial test validates the product and protocol’s efficacy, and subsequent tests validate the protocol execution throughout the product’s lifespan (assuming the product did not expire prematurely). If both tests pass, the practice can begin testing every six months. If there is a test failure, the clinician should shock immediately and retest per the waterline treatment manufacturer’s IFU. I personally recommend testing through a third-party lab that specializes in dental water microbes, like Agenics They offer HPC counts and many other water chemistry metrics that help diagnose problems should they arise.”

Legal precedent
Compliance with water safety standards in the United States has not been required by law. But, that’s quickly changing. “Water compliance may not have been the law in 2016, when 73 pediatric patients contracted Mycobacterium infections from contaminated dental water at Children’s Dental Group in Orange County, California,” says Mendolia.  However, in 2019, it will become a law in California, he points out, noting that eventually much of the country will likely follow suit.

“What I try to impress on people is that this issue isn’t going away,” he says. “Now that there are legal precedents associated with patient vs. clinicians, and manufacturers vs. clinicians, with regard to this topic, it will be difficult for dental clinicians to prove in court that they are not responsible for any infections related to dental water in their practice, even if they weren’t legally required to take action.”

That said, for some dental professionals, cost will always be an obstacle. “We must focus on the relative cost per liter differences among the various products, relative to their overall need for water,” says Mendolia. “If a large practice intends to confront this problem head on, it would serve them well to go with the option that has the lowest cost per liter. That’s not always the lowest initial cost, but the purchase will pay for itself with time.

Sometimes dental practices just want to get their toes wet, so to speak. “Low cost options like Citrisil tablets are a good place to start, with the same great treatment you get from the higher end products,” he says. But, they’re not as convenient as a long-term solution. “The low-cost options in this category always leave something to be desired when it comes to efficiency and cost per liter.”

As more practitioners are on board with the need for waterline treatment, they are looking for solutions that provide enhanced efficiency and require less staff involvement, notes Mendolia. “We are here to help,” he adds.