While Dr. Aanestad correctly affirms my observation that there is little evidence of an urgent public health crisis over dental water contamination, I feel that he is otherwise misguided in his interpretations. The literature does in fact document possible cases of illness associated with contaminated dental treatment water.
The profession’s ability to discern whether these few cases represent a true paucity of health effects or the tip of an iceberg is severely limited by the almost total absence of epidemiologic data on both clinic-acquired and occupational illnesses in dentistry.
The nature of dental practice and a number of practical and ethical considerations make it very unlikely that such data will soon, if ever, be collected.
If the issue of dental waterline contamination is indeed of little consequence to our profession, it might be simply demonstrated by a controlled clinical trial. Patients undergoing surgical or restorative dental treatment could be randomly assigned to two groups and then exposed to aerosolized water meeting current drinking water standards or water containing thousands or millions of water bacteria, including naturally occurring strains of Legionella pneumophila, Pseudomonas aeruginosa and aquatic mycobacteria. The subjects could then be assessed for potential systemic or local effects and the groups compared.
Of course, it is extremely unlikely that such a study would ever be conducted, let alone approved by an institutional review board. It also is unlikely that patients would readily consent to such a protocol. Unnecessarily exposing patients to large numbers of exogenous microorganisms, some with documented pathogenic potential, simply defies the basic principles of infection control.
Though an empiric principle, reducing potential exposure to microorganisms during medical and dental procedures is the most basic element of infection control practice, dating back to the days of Semmelweis and Lister.
Improving the quality of water used in dental practice is entirely consistent with this principle. I presume that Dr. Aanestad would not urge the profession to abandon the practices of handwashing, instrument sterilization and surface disinfection based on the lack of direct scientific evidence that dirty hands, unsterilized instruments or soiled surfaces have resulted in illness.
I am disturbed by Dr. Aanestad’s suggestion that we should hesitate to discuss waterline contamination for fear that it will provide ammunition for the legal profession and a rationale for additional regulations. The lack of scientific acumen among legislators, lawyers and the general public should not serve as grounds for avoiding public scientific discourse on the issue. Should dentists be less well-informed about such issues than their potential adversaries?
Historically, dentistry has not been well-served by responding in a reactive rather than proactive fashion to earlier controversies (examples: fluoridation, amalgam). The public tends to view such responses as disingenuous and protectionist, irrespective of the scientific evidence presented, and the net result is a loss of respect for the integrity of the profession. I am very proud that our association has had the courage to take a proactive stance in educating the profession and the public in a nonalarmist manner on the issue of dental waterline contamination.
While Dr. Aanestad may argue that the conclusions I have drawn in the article do not "show [him] the science," they are totally consistent with the concept of evidence-based health care. This concept—now widely accepted as the basis for modern medical practice—involves the use of available scientific evidence, supplemented by the empiric clinical judgment of the clinician where scientific evidence is lacking. This judgment is drawn from the individual experience of the clinician as well as the collective experience of the profession.
Medicine and dentistry have been well-served by the empiric infection control principles first articulated over 150 years ago. The practice of unintentionally inoculating patients and health care workers with large numbers of organisms of uncertain pathogenic potential is clearly inconsistent with these principles—especially given that reasonable, scientifically validated means to improve the quality of water used in dental treatment are now available.
In conclusion, I make no apologies for reaching the "logical" conclusion that "water that is unfit to drink as defined by nationally recognized standards is unsuitable for therapeutic use in dentistry." Although I have no firm scientific data to confirm it, I am confident that most of our patients would agree.
