"Will dental unit water be the next target of mass tort litigation?"

Reprinted from Dental Malpractice Prevention, Vol. 1, No. 1, March 1997

Although it has been almost thirty years since the phenomenon of dental unit water contamination was first noted in published literature, the past few years have witnessed a proliferation of scientific articles, governmental regulations and recommendations, and, more recently, popular media reports concerning the subject area.

These developments have culminated in the adoption of related policy statements by the American Dental Association. This recent activity, coupled with calls for further research, poses not only a scientific challenge for the dental profession, but a legal one as well.

This article focuses on the concept of mass tort litigation and identifies the factors leading to the conclusion that dental unit water contamination is a prime area for mass tort litigation. In next month's issue, a follow up article will explain how to avoid being caught in the legal web that may result.

Mass tort litigation is a phrase lawyers use to describe situations in which multiple law suits, brought either as individual suits or as "class actions," are filed throughout the country seeking damages allegedly arising from the use of or exposure to a particular drug (DES, Prozac), product (breast implants, cigarettes, latex gloves, asbestos), or other environmental hazard (airborne, soil or water contaminants such as dioxin and radon).

Mass tort litigation did not become a part of the American legal landscape until the early 1970s, but since then, it has become a prominent feature. Plaintiffs personal injury attorneys regard mass tort litigation as a "pot of gold." They actively seek out and vigorously promote new areas of potential litigation.

Two primary factors produce mass tort litigation: the potential for substantial attorneys fees and the "opportunity" presented by new scientific knowledge or discoveries relating to a perceived health hazard.

The larger the pool of potential plaintiffs (allegedly injured persons), the greater the incentive to invest time and money prosecuting a given type of case, and the greater the potential financial windfall for attorneys who collect one-third or more of damages recovered for each plaintiff.

Potential financial gain is also influenced by the types of damage claims plaintiffs are likely to raise. Serious medical conditions or fatalities provide the greatest potential recoveries, and, therefore, the biggest incentive for pursuing such claims in litigation. However, uncertain or less serious injuries may be offset by the sheer volume of potential claims, particularly with the advent of class action lawsuits.

The number of people exposed to dental unit water and the microbial pathogens reportedly contained therein is enormous, exceeding the number of cigarette smokers, breast implant patients, persons exposed to asbestos, etc. Even assuming that only those persons with compromised immune or pulmonary systems would likely be affected by the pathogens transmitted through dental unit water, there may still be millions of potential cases.

Significant adverse medical conditions, including fatalities, can arise from exposure to the types of bacteria reportedly existing in dental unit water, and the viruses potentially transmitted through dental water contamination.

The current state of medical knowledge may make it difficult to prove that an individual's medical condition resulted from exposure to contaminated dental water, but many states allow individuals to file suit and recover damages for "fear of" contracting an illness, and for the cost of medically monitoring an individual's state of health.

The "opportunity" that represents the second requisite factor for mass tort litigation is based on the attainment and dissemination of scientific knowledge, leading to significant medical, industry, governmental, and, eventually, public concern about and reaction to a potential health danger. Plaintiffs personal injury attorneys seize on newly available science, regulations and concern to formulate a viable, and often effective, litigation plan.

The fact that scientific "state-of-the-art" has not yielded sufficient epidemiologic evidence to establish a scientifically valid causative link will not deter motivated plaintiffs attorneys from acting "precipitously."

Legal liability does not require true scientific proof; rather, legal liability involves presenting sufficient evidence to persuade a jury of ordinary laymen.

The ability of plaintiffs attorneys to gather evidence in the context of mass tort litigation is a function of their ability to identify and form alliances with scientists who are willing to define 'reasonable scientific probability" broadly to achieve the goals of the litigation. This scenario is neither speculative nor cynical; it merely reflects the reality of today's civil justice system.

All of the signs are present to indicate that contamination of dental unit water may become the next hot area of mass tort litigation: a nearly unlimited pool of allegedly "injured" plaintiffs, scientific literature documenting the potential health risk, emerging government regulations, and public awareness raised by popular media reports.

Not all dentists and manufacturers will face the same risk of being drawn into such litigation. In the next issue(see below), Dental Malpractice Prevention will highlight the key factors likely to determine liability in cases of alleged dental unit water contamination, and will outline recommendations that will help you minimize or eliminate your risk.

Dental Unit Water Contamination - What you need to know to minimize your liability risk

Reprinted from

Dental Malpractice Prevention, Volume 1, No. 2, April 1997

If one of your patients becomes ill as a result of exposure to a pathogen or bacteria that is later found in your dental unit water, you are at risk of being held responsible for your patient's illness and associated compensatory damages.

If the patient was immunocompromised or had a significant respiratory condition when you treated her, your risk of liability and the potential damages at stake are even greater. In last month's issue, Dental Malpractice Prevention identified the reasons that dental unit water may become the next target of mass tort litigation. This article outlines what you can do to decrease your potential liability.

Keeping up with a constantly changing "standard of care"

Decreasing your liability exposure does not require that your dental unit water be entirely germ free. Rather, your degree of risk is a function of the extent to which you employ reasonable protocols in your practice designed to limit your patients' exposure to disease-producing organisms.

In other words, whether you are vulnerable to a lawsuit depends on whether you ant your office staff have adopted and followed infection control procedures that comply with the standard of care.


The "standard of care" is an amorphous legal concept generally defined as the minimum acceptable conduct that would be expected of a reasonably well-qualified dentist under the specific circumstances in question. Although they are rarely "written in stone," and are open the subject of disagreement among "expert,' witnesses, there are standards of care for many aspects of your practice, including conducting oral examinations, arriving at a diagnosis, taking radiographs, charting, informing patients of treatment options and risks, and clinical skill in providing treatment.

Whenever a practitioner's professional conduct is assailed in a malpractice lawsuit, the ultimate proposition the patient must prove is that the dentist failed to comply with the applicable standard of care.

In some areas of practice, compliance with the standard of care is made difficult by the fact that standards change as the clinical, technological and scientific state of the art evolves. In the "good old days," the state of the art in science and technology changed slowly, and the standard of care remained the same over relatively long periods of time.

We now live in an age in which continuous scientific research yields new information, spurring rapid advances in the state of the art, and constantly reshaping the corresponding standard of care.

The problem of contaminated dental water has recently become the subject of numerous published scientific and professional articles and educational presentations. Governmental agencies, professional associations, and others have issued recommendations, statements and regulations.

Dentists can no longer pretend there is only a theoretical problem. Now that the state of the art has illuminated dental water contamination as a potential health risk, dentists must acknowledge the problem, stay abreast of the rapidly evolving standard of care, and do their best to comply with the standard of care in daily practice.

At this time, defining a precise standard of care for infection control procedures directed to dental waterline contamination is difficult. There is substantial debate among dentists, industry, scientists, professional associations and government regulators as to the protocol and/or technologies dentists should employ to reasonably limit infection of patients or dental staff from waterline contamination.

However, several relatively easy-to-adopt measures have been recommended that may represent a current minimum standard of care. More importantly, statements regarding maximum acceptable levels of bacteria, complete with existing and developing technologies capable of achieving those levels, arguably point to a higher standard of care that dentists will need to meet within the next few years.

Emerging standard of care may be reflected in recent statements by ADA, CDC, and OSAP

The December, 1995, "Interim Recommendations" of the ADA, which substantially adopted the CDC's 1993 Recommended Infection Control Practices for Dentists (MMWR 42: No. RR-8:7, 1993), suggested the following specific protocols, including interval flushing of waterlines and hand pieces, engaging in proper maintenance of dental units in accordance with manufacturers' recommendations, and using sterile water when performing certain invasive surgical procedures.

The ADA also recommended that dentists "give consideration to" the use of commercial options for improving water quality. See J Am Dent Assoc, 127: 188, 1996.,

Perhaps more importantly, the ADA has encouraged improvement in the design. of dental equipment so that by the year 2000 dental unit water used in nonsurgical procedures should consistently contain no more than 200 colony-forming units per milliliter (CFU/mL) of aerobic heterotrophic mesophilic bacteria at any point in time in the unfiltered output of the dental unit. See J Am Dent Assoc, 127: 185-189, 1996.

(See ADA position statement from JADA article)

The Office of Strilization & Asepsis Procedures (OSAP) Research Foundation, in the recent position paper developed by its Dental Unit Waterline Worlcing Group, specifically concurred with the recommendations of the CDC and ADA on the control of microbial contamination in dental unit waterlines and attempted to proYide a frarnework for collaboration between industry, scientists and dental practitioners to achieve improvements in tho quality of dental water. Many of the statements in the position paper envision current and future development of commercially applicable technological solutions to tho tental water contamination problem.

Although OSAP expressly disclaimed that its statements were intended to serve as a "clinical manual ' the working group did point out in its conclusion that:

"When used in a conscientiously applied manner, both properly maintained separate water rescwoir systems and microfiltration technology can produce treatrnent watcr with 200 or fewer CFU/mL of heterohophic mesophilic bacteria. A combination of these approaches may offer the best available assurance of high quality dental treatment water quality. Sterile water delivcry systems are also available which use either heat sterilizible or sterile disposable components." Dental Unit Waterlines Position Paper, OSAP Research Foundation, at 4 and footnotes =6, January, 1997.

OSAP also cited three published studies indicating that mechanical flushing of waterlines alone has not been shown to consistently reduce the number of bacteria present in water used in dental treatment.

Assuming the avai!ability of technologies that can consistently produce water meeting the 200 CFU/mL threshold espoused by the ADA, it is difficult to imagine any legally valid or persuasive excuse for a dentist not to employ those technologies and not to develop office procedures to ensure that they are applied conscientiously and maintained in accordance with manufacturers' recommendations.

Califomia has enacted a statute mandating a specific protocol with respect to dental water. California dentists must follow the requirements of Section 1005 of the California Dental Practice Act, enacted April 7, 1996. Abiding by these protocols is necessary not only to avoid potential civil liability, but also to maintain licensure.

However, compliance with the Califomia Dental Practice Act does not ensure compliancc with the standard of care for purposcs of a civil lawsuit---the standard of care can require a higher level of conduct than a statute requires.

The statement and interim recommendations of the ADA, the recommended infection-control practices of the CDC, and the statements in OSAP's Dental Unit Waterline Position Paper do not establish the standard.of care by which a dental practitioner will be judged in a malpractice case.

However, those statements and recommendations, and the published scientific articles on which they rely, together with the opinions of "expert" witnesses, will comprise the evidence from which a jury will determine whether a defendant dentist has complied with the standard of care. The statements, recommendations, and literature take on added significance to the extent that the expert witnesses must utilize them to form and bolster their opinions.

In a malpractice case, the jury ultimately determines what the standard of care is and whether the defendant dentist has met it. The practitioner's goal should be to avoid putting himself at the mercy of a jury by minimizing his risk of being sued. It is clear that those dentists who do not attempt to comply with the CDC's and ADA's recornmendations will be the favorite targets of attorneys filing suits relating to illnesses allegedly caused by dental unit water contamination.

Conversely, dentists who employ technologies and protocols meeting or exceeding those recommendations will be less attractive targets.

Dentists who employ the additional available technologies and protocols, and who can also demonstrate, through periodic monitoring, that they meet the 200 CFU/ml ADA threshold will be the least likely targets of all, and any cases filed against them will be very desensible.

Go to Comparison of Dental Disinfection Products

to determine which products meet(or do not meet) the ADA 200 CFU/ml threshold.

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