A few months ago, The Journal of the American Dental Association presented an editorial urging clinicians to become familiar with the uses and abuses of numbers demonstrating the superiority of a new product or technology.¹ The editorial noted that clinicians are exposed to claims from both commercial and scientific sources that tend to put an innovation in the best possible light in terms of risk reduction. It argued that the claims must be evaluated carefully and interpreted in the context of the clinician’s practice before the utility of the innovation becomes clear.

This commentary extends that argument by reminding clinicians that they need to maintain a healthy level of skepticism about everything that they read, and during every presentation that they attend. The need for skepticism arises because much of the information that captures a clinician’s attention is designed to do precisely that, and may not represent a valid or balanced presentation. In addition, even procedures such as peer review or provider accreditation, which are used to help ensure that information is scientifically sound, occasionally fail.

An example of such failure is the recent appearance in these pages of a study describing the performance of a laser-fluorescence method for detecting occlusal decay.² The method was reported to return impressively high sensitivity and specificity results, but even a cursory reading of the methods shows that the investigators used no histological "gold standard" for caries detection, which is necessary to ensure that lesions identified by a detection method really are carious. Instead, the performance of the laser device was simply compared with that of a visual examination. The device detected most of the lesions that the visual examination detected, but it also identified twice as many additional surfaces as having lesions. However, these additional surfaces were not evaluated histologically to determine if they were true- or false-positives. Thus, the actual performance of the laser device cannot be determined from the data presented.

Should clinicians be expected to identify such lapses in validity? The answer must be "yes." As noted, information saturates the environment, and not all of it is accurate. To make clinical decisions based on uncritical acceptance of new information is akin to playing Russian roulette: eventually, it will catch up with you. Yet dentists are professionals, and as such they are held responsible by society for keeping abreast of the dental knowledge base and using the most current information in their treatments. Thus, it is inevitable that dentists must seek, adopt and act on new information. The question is how to decide which information to adopt and act on.

Part of the answer is to be critical, to receive all new information with a critical attitude. At the most basic level, clinicians must be forever vigilant about the veracity of all clinically relevant information, be it a published study, information from a sales representative or an advertisement, a continuing dental education presentation or even a tip from a colleague. Critical appraisal is an approach to which most dentists were exposed during their professional education, but one that many have not practiced consistently since graduation. But a large component of critical appraisal is simply common sense, and that is a skill that most professionals have in abundance.

Applying common sense to the methods and results of a typical clinical study will help answer three critical questions. The first is whether the study is at risk of bias—whether there is a plausible alternative explanation for the results, that is, other than what the researchers claim. The second question is whether the results are clinically significant, and the third is whether the results are applicable to an individual clinician’s patients. Answering these three questions is a large step toward deciding whether the information is worthy of adoption and action.

Another part of the answer is to proactively select information on which to act, rather than wait for it to appear. Perhaps the most consistently unbiased source of clinically relevant information is the systematic review. These reviews answer clinical questions. The rather strict protocol for conducting a systematic review is designed to ensure that all relevant information, or evidence, concerning the clinical question is included in the review, that the quality of the individual clinical studies that constitute the evidence is evaluated and is considered in arriving at the review’s conclusions, and that the conclusions are based on an objective synthesis of the individual studies. More than 700 systematic reviews are listed in a searchable database on the ADA’s evidence-based dentistry Web site ("http://ada.org/prof/resources/ebd/index.asp").

At the most basic level, clinicians must be forever vigilant about the veracity of all clinically relevant information, be it a published study, information from a sales representative or an advertisement, a continuing dental education presentation or even a tip from a colleague.

Later this year, the ADA’s new, enhanced evidence-based dentistry Web site will debut, and critical summaries of many of these reviews will begin to appear. These critical summaries are a product of the Association’s Evidence Reviewer Program, and JADA will begin to feature one or more critical summaries in each issue. The critical summaries present an abstract of the systematic review and brief commentaries on the review’s methods, the strength of the reported evidence and its clinical implications, all in a single-page format. These critical summaries can be used both to answer clinical questions and to get background on a clinical question that a new study purports to answer. As a part of being critical, asking the question "What’s already known?" often will provide an objective perspective on the question that is not offered by the new study.

Thus, "keeping critical" is an active process, and one that society expects professionals to do, and do well. The ADA is helping by providing Web-based and Journal-based resources that offer the most unbiased information available, but clinicians bear the primary responsibility to evaluate new information critically, and to apply it judiciously.