Evidence-based medicine (EBM) has been described as “the conscientious, explicit, and judicious use of current best evidence in making decision about the care of individual patients.” One of the defining characteristics of EBM is that formal processes are used for assessing the reliability of the clinical evidence used to inform clinical decisions. The drivers of the EBM movement have been the need for reliable information by busy clinicians, the shortcomings of traditional sources of information (eg, textbooks), the availability of online databases that serve as repositories of this information, the limited time available to physicians to access information, and the electronic technology that has made searching the databases a simple matter. Another enabling factor is the maturation of clinical epidemiology as a discipline and its application to decision-making in health care. Currently pressure has increased to improve patient outcomes, reduce medical errors, make health care more accessible, and reduce medical expenses. Ample evidence shows that medical decision-making is often inconsistent and not based on best evidence or practices. EBM may help alleviate these problems and contribute to improving the quality and consistency of health care.

After a slow start, EBM is beginning to exert a profound effect on health care. Dentistry has been slower than medicine to adopt evidence-based strategies, but this is changing. Recently, the American Dental Association (ADA) held two evidence-based dentistry (EBD) conferences to promote this concept. The ADA hopes to create a cadre of “EBD Champions” who will, it is hoped, return to their communities or institutions and promote EBD and its many benefits. Because the conceptual foundation and tools of EBM and EBD are the same, this article uses the more inclusive term evidence-based health care (EBHC) to refer to these concepts.

EBHC consists of five steps, which have been described in greater detail elsewhere:

• 1.

  Convert the need for clinical information into an answerable question

• 2.

  Find and rank the best evidence with which to answer the question

• 3.

  Critically appraise the evidence for validity, impact, and applicability

• 4.

  Integrate this evidence with clinical expertise and the patient’s unique circumstances and preferences

• 5.

  Evaluate effectiveness and efficiency in executing steps 1 through 4

The first step is to convert the clinician’s need for information into an answerable question. This question may be more “background,” which is concerned with a gap in general knowledge about a condition, diagnostic test, or intervention. A dental example might be “Does oral bisphosphonate therapy have an effect on implant survival?” Questions concerning the specific management of a patient may be termed foreground questions . For example, one might ask, “In a 45-year-old female smoker with osteoporosis, what is the risk for implant loss?” The relative need for background or foreground information varies with clinical experience. When dentists have little experience with the condition of interest, more background information is required, which is the situation for third-year medical or dental students (or experienced clinicians who are confronted with an unusual clinical condition). When dentists have more experience, they are more likely to require focused information relating to specific patient management issues (eg, the situation faced by a second-year resident or an experienced clinician).

The second step is finding the best evidence with which to answer this question and then ranking it according to the hierarchy of evidence shown in Fig. 1 . Individual studies are at the bottom of this pyramid, whereas databases or repositories in which syntheses of evidence may be located (eg, the Cochrane Library) are somewhat higher. Synoptic journals are next, followed by computerized clinical decision support systems, which are capable of assimilating the data for a given patient and suggesting interventions (or further diagnostic tests) based on best evidence.

Hierarchy of evidence. ( Adapted from Straus SE, Richardon WS, Glasziou P, et al. Evidence-based medicine: how to practice and teach EBM. Edinburgh: Elsevier Churchill Livingstone; 2005; with permission.)

Ideally, there would be a seamless link between the clinical decision support system and the patient’s electronic health record, so that suggestions regarding the patient’s diagnosis and treatment would be made in real time as data is entered into the chart. This system would be automatically updated with the latest best evidence as it became available. Obviously, these systems are not in general use, but the soundness of this approach has been shown, particularly in the area of prescribing multiple medications for hospitalized or geriatric patients. To date, the applications with the most immediate usefulness have been those that promote guideline adherence and alert providers to drug interactions or treatment omissions. Examples include computer provider order entry systems combined with clinical decision support systems, which have been shown to improve patient safety through reducing the incidence of adverse drug interactions.

The third step of the classical EBHC process is critical appraisal of the evidence. Evidence must be screened for validity, impact, and clinical applicability. Of particular interest is the concept of external validity . A study is said to possess external validity when it can provide “unbiased inferences regarding a target population (beyond the subjects in the study).” This finding is a function of the study population vis-à-vis the research hypothesis. If a study on melanoma risk factors recruited only Caucasian women, the conclusions generated may not apply to African American men, who experience a much lower incidence of this cancer. Populations differ and these differences may have an important effect on study outcomes.

Another example of this population difference is the prevalence of a genotype associated with severe periodontitis. The genotype is present in approximately 30% of individuals of northern European descent, but a study in a Chinese population found a prevalence of only 2.3%. These differences must be considered when extrapolating the results of a study to a more general (or different) population than the study sample.

The impact of the evidence can be measured by the size of the treatment effect for therapeutic interventions. This effect can be reported in a number of ways, depending on the intervention. For example, the relative risk reduction is useful in describing the protective effect of a therapy (eg, fluoride varnish). For other types of interventions, a relative benefit increase may be more appropriate. One particularly useful concept is the number needed to treat, which is the number of patients that must be treated with the therapy in question to prevent one additional bad outcome (however that is defined).

The impact of a diagnostic test can be assessed through examining the sensitivity, specificity, positive predictive value, and negative predictive value. Finally, the intervention must be clinically applicable to each unique patient. This critical appraisal is at the heart of the EBHC concept and is, to a large extent, what Straus and colleagues refer to as “doing” EBHC. The basic process is often referred to as “critical thinking” in academic health care, and it is a critical competency for clinicians, regardless of discipline.

EBHC has begun to appear in the dental curriculum. These EBHC experiences often consist of sending students to the library, where they conduct searches of the primary literature on some assigned topic and then critique the papers found. These worthwhile exercises are performed with the laudable goal of fostering “critical thinking.” Students are assumed to carry these skills into practice and used to improve patient outcomes.

Unfortunately, busy clinicians have insufficient time to perform lengthy analyses of the primary literature. Lack of time is cited as one of the drivers of the EBHC movement. Sackett and colleagues originally envisioned EBHC as a quick and efficient way to access best evidence and found that making evidence readily available increased the likelihood that this evidence would be used in making clinical decisions.

Obviously, critically analyzing one randomized controlled trial is an intellectually valuable exercise for health care students. As valuable as this exercise is, however, it is incomplete because it does not really give students a good model for incorporating EBHC into clinical practice. What is needed is quick access to robust information, such as that supplied by systematic reviews or meta-analyses like those found in the Cochrane Library or similar sources. Only when these reviews are not available should a search of the primary literature be required. Unfortunately, most clinicians will have neither the time nor the inclination to perform their own reviews (and may be hard-pressed to conduct searches for even single articles).

In this regard, a useful distinction might be made between “doers” of EBHC and “users” of EBHC. Straus and colleagues point out that clinicians may shift back and forth between the “using” and “doing” modes. They note that “while some clinicians may want to become proficient in practicing all five steps of EBHC, many others would instead prefer to focus on becoming efficient users (and knowledge managers) of evidence.” Although students of all health care disciplines must be competent in both “using” and “doing,” it seems that they must at least be able to access and use best evidence, which involves different tools and a different approach than “doing” EBHC. University of Kentucky College of Dentistry (UKCD) requires students to be competent in both modes, but has emphasized the “using” mode in clinical protocols and education, because they believe it to be the mode most likely to be used by most graduates.

A small group at the UKCD became interested in using EBHC principles to enhance curriculum and clinical services. This article presents a brief review of UKCD’s initial experiences in implementing this initiative. Although they are in the process of creating a predoctoral clinical curriculum based on the concepts of EBHC, much of their experience has been in the Graduate Periodontology Program. The goal was to fully and seamlessly integrate EBHC into the clinical curriculum. The idea was to make it truly an organic part of the clinical and educational missions of the college, because they believed this was the best way to show the usefulness of EBHC to skeptical students and faculty.

The goal was to use the principles and tools of EBHC to guide clinical decision making through the creation of evidence-based treatment protocols for commonly encountered clinical situations. This information was to be incorporated into didactic coursework and applied in the clinical setting. These clinical protocols were to be easily accessed by students, faculty, and staff. This represents a more holistic and integrated form of EBHC than an individual course devoted to EBHC (although the two approaches are not, of course, mutually exclusive).

Korenstein and colleagues reported a similar program at Mount Sinai School of Medicine, in which EBHC is fully integrated into clinical curricula, including women’s health and addiction medicine. The programs have been well received and plans call for expanding this approach into other areas of the curriculum.