CRA Response
to ADA News, A-dec, & OSAP on Dental Unit Waterline Disinfection Controversy
Back to Unit Waterline Testing Results

Different points of view are healthy in science. In fact, critical review without malice is the system of science. However, over the past 8 weeks, CRA has found its report on dental unit waterline treatments very publicly attacked and censured without what CRA considers scientific basis, and by people who have shown CRA no data produced by themselves to support their allegations. Therefore, we are forced to express CRA’s point of view concerning the motives, as well as the use of the media for attention. Is this really without malice? Are the disinfectants tested by CRA really so hazardous that they are out of the question for dental waterlines?

Without contacting CRA to notify; investigate; or request methods, data, comment, or response, the following sequence of events took place:

    1. Sept. 22, A-dec dental equipment company issued a memo to its salespeople excluding use of 3 of 5 disinfectants in CRA’s report as not allowable within their warranty. However, their warranty already states clearly that "The warranty does not cover damage resulting from use of cleaning, disinfecting or sterilization chemicals and processes".  Therefore, this was a very strange and unnecessary action.

    2. Sept. 22, OSAP (acronym stands for Office Safety and Asepsis Procedures— a group of about 50 companies selling infection control products and about 1000 people interested in infection control in dentistry) adopted a statement condemning as "inappropriate" 3 of 5 disinfectants in CRA’s report.

    3. Sept. 24, ADA Council on Scientific Affairs adopted a statement expressing "serious reservations" about CRA’s report, and warning against use of 2% glutaraldehyde, which was 1 of 5 disinfectants in CRA’s report.

CRA believes there are four important points related to the above series of events:

    1. All 3 groups took it upon themselves to condemn a large body of data, almost 2 years in the testing, which none had ever seen, nor indicated a desire to see in the future.

    2. At least one author of OSAP’s statement is an A-dec employee, and another author is both a charter member and leader in OSAP and an appointed consultant to the ADA Council on Scientific Affairs.

    3. The close succession of similar actions by three different groups suggests a united effort.

    4. All 3 groups showed an unusual hastiness.

At this point, there are two primary questions:

  1. Are there interests, other than the alleged hazard claims, possibly driving the condemnation of CRA’s report?

  2. Are the 5 disinfectants tested by CRA so hazardous they should not be considered for use in dental unit waterlines?

To understand the first question of what interests could possibly be driving the condemnation of CRA’s report, clinicians need to be aware of the huge profit potential involved in selling a waterline treatment that needs to be used regularly in all syringe and handpiece waterlines, on every dental unit, in every dentist’s office in the U.S. and Canada, regardless of specialty.

Calculations based on using 100 ml of a chlorhexidine disinfectant in daily overnight treatment, in a 3-operatory dental office, working 240 days a year, 130,000 U.S. dentists and 10,000 Canadian dentists, amounts to a 200-300 million dollar per year business.

Would this amount of money cause an adverse reaction to a report like CRA’s that informs clinicians that common disinfectants, readily available in the office and already used safely for many years, can be used for dental unit waterline disinfection? 

Would the best approach to discredit CRA’s report be to claim the products tested are hazardous?

CRA had the following scientific reasons for including of each product in the study:

    1. 2% glutaraldehyde was included because —
    (a) Glutaraldehyde has a 10 year precedence of use as a dental unit waterline disinfectant in Castellini equipment from Europe, which has been sold in the U.S. since 1992. The design of this equipment accomplishes the waterline goal of efficacy and safety, right now—today. Therefore, glutaraldehyde and Castellini equipment cannot be ignored.
    (b) Glutaraldehyde is the only true broad spectrum disinfectant used in dentistry. It has FDA clearance as both a high level disinfectant and sterilant. Of all the disinfectants tested by CRA, glutaraldehyde reduced waterline counts most reliably, without damage to the units or harm to patients.
    (c) The dental literature shows several other research groups in the past have tested glutaraldehyde in dental waterlines. If glutaraldehyde is so hazardous, that it required a highlighted page-one warning in the ADA News, why are clinicians all over the world handling it (for the past 22 years), multiple times every day for instrument disinfection? If the possibilities of intraoral contact and accidental swallowing pose worries, why has glutaraldehyde been permitted at more than double the 2% concentration for placement onto freshly cut dentin for the past 10+ years as Gluma Desensitizer and Gluma Adhesive Primer, and why is Syntac Adhesive Primer with 5% glutaraldehyde in ADA’s booklet of "Products of Excellence" accepted for the ADA seal?   We submit there are gross inconsistencies in the ADA’s attitude toward glutaraldehyde. We further submit that glutaraldehyde is a valuable disinfectant that has received enormous "bad press" by unscrupulous salespeople whose inferior disinfectants couldn’t compete unless glutaraldehyde could be discredited. We have seen use of MSDS forms for 50% glutaraldehyde passed off by dental salespeople to unsuspecting clinicians as hazards to be expected from 2% glutaraldehyde—a product 25 times less concentrated!
    1. Bio-2000 and Hibiclens, both chlorhexidine-based products, were included because Bio-2000 has specific directions for use in dental waterline treatment, and Hibiclens was diluted to represent a more concentrated form of the same active ingredient, where no commercial product was present.

    2. Bleach diluted 1:10 was used because it is recommended, in written instructions for use once a week, in dental equipment. Because CRA tests showed that, clinically, this weekly regimen did not maintain the <200 cfu/ml counts reliably for a full week, daily and overnight use regimens were also tested, for comparison.

    3. Everclear food grade ethyl alcohol was included because it is the only product that is both a potent disinfectant and a human beverage, making hazard concerns less pressing. CRA most certainly did consider safety of the disinfectants tested, both at the planning stages of the study when decisions were made to include ethyl alcohol, and continuing throughout the project. Therefore, accusations that safety was ignored can be verified as untrue.  Had the accusers conducted an investigation, this would have been evident.

It is important to note that all the disinfectants above, and all other disinfectants pose potential hazards to both clinicians and patients. Chemicals that kill microbes well are not innocuous to humans. To target one disinfectant as more hazardous than others is both misleading and inaccurate. CRA found very small amounts of dental unit water are ingested by patients. The vast majority of the water expelled from syringes and handpieces is either suctioned away or expectorated. If a mouthful of 1:10 bleach was swallowed, it would elicit a low level acute reaction, and the same would be true of glutaraldehyde. As yet, CRA has not run LD50 tests on the disinfectants tested, but this does not indicate a negligence on CRA’s part because we do not see these assays in the work of other researchers of dental waterline disinfectants. 

FDA clearance will eventually establish acceptable hazard levels for disinfectants needed for dental waterlines. However, in their written statements, A-dec, OSAP, and ADA all failed to tell clinicians that there is considerable confusion at this time as to which, if any, of the disinfectants used commonly today has FDA clearance for dental unit waterline disinfection.  Bleach 1:10 has not been confirmed as safer than 2% glutaraldehyde, chlorhexidine, or ethyl alcohol. Household bleach is a very potent chemical. For waterlines it must be diluted with 9 parts of water before each use which requires substantial handling. Furthermore, it resists addition of safety dyes that warn of its presence in dental waterlines. Also, bleach corrodes metal and degrades o-rings causing water syringe valves to stick in the "on" position and black material to be emitted in syringe water. Yet with all its obvious problems, ADA and OSAP made no objection to use of bleach, and A-dec recommends its use in writing. Is this science, politics, or commerce?

CRA stands by its work and its 22 year record of integrity, impartiality, and thoroughness. CRA is accused of failing to note safety and efficacy of the 5 products tested, yet these points are the central purposes of the report, and this was so stated, twice in bold print, and a third time in the conclusions. CRA’s work is ongoing—it never stops. Even as you read this, other products for dental waterlines are undergoing testing. Every time we find something that works and is clinically useful, we will write and speak about it so you can try it in your own office to see if it fits your needs. At least you will know it has passed extensive testing by CRA, and can deliver certain advantages, but CRA will also make you aware of its disadvantages. If this approach ruffles feathers, then look closely to discover why. CRA has hands-on data to validate every statement it makes. Our accusers have not shown CRA any data to prove their opinions and recommendations, let alone data produced by their own hands-on testing in their own microbiology labs. CRA believes that speakers and authors have the legal and moral obligations to prove their statements with personal, hands-on work. CRA believes, anything less, is both dangerous and irresponsible!

It is appropriate here to mention criticisms that the CRA Newsletter is not "peer reviewed" like some journals. The CRA Newsletter has never pretended to be a journal. It is a dental products newsletter, and this is clearly stated in large print on its masthead. The CRA Newsletter is like an "interoffice communication" among dental clinicians reporting their experiences with various products. This information undergoes the most stringent "peer review" possible when thousands of clinicians internationally use the products and techniques reported. Until dental products meet all their promotional claims, CRA believes that clinicians have the responsibility to continue this type of communication and to do everything else they can to protect their patients from products that do not meet clinical expectations.

The clinicians who started CRA 22 years ago believed they could trust each other as "clinical peers" more reliably than anyone else to discover and disclose which products do, and do not, meet expectations in patient treatments. In time, everyone becomes a patient… even you. Who are you prepared to trust? In this current controversy, each person reading the exchanges will ultimately make that decision. We submit that CRA has no reason to mislead. We have told the truth and the truth stands the test of time.  CRA has performed thousands of hours of microbiology on this enormous project, we have reported honestly and candidly, with no ulterior motives. CRA wonders if the same can be said of it’s detractors.

October 30, 1997

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