Evidence-based dental practice: part III. Critical appraisal of the literature, relevance and application of the evidence.

Evidence-based dentistry involves defining a question focused on a patient-related problem and searching for reliable evidence to provide an answer. Once potential evidence has been found, it is necessary to determine whether the information is credible and whether it is useful in one's practice by using the technique of critical appraisal. This article discusses the guidelines that have been developed to guide clinicians in assessing the validity and the relevance of published studies (randomized control trials, systematic reviews, cohort studies and case-control studies). The concept and tools of "critical appraisal" of published research works were developed by the evidence-based medicine group at McMaster University, Canada.