Evidence and knowledge gaps in dentistry

The practice of evidence-based dentistry means integrating individual clinical expertise with the best available external clinical evidence from systematic research. Individual clinical expertise means the proficiency and judgment that individual clinicians acquire through clinical experience and clinical practice. It follows that a systematic review can help the clinician to gain knowledge about the evidence of a certain intervention or a certain diagnostic method. This article focuses on the rationale behind the systematic review and how it is conducted. The process starts by formulating one or more relevant questions. Inclusion and exclusion criteria are decided regarding study design, population, intervention, control, outcome, and outcome measures. The process then involves literature search and data extraction of relevant, full text articles. Quality assessment of relevant studies, conducted by at least two independent readers, is performed using quality assessment forms. Based on the quality of the included studies, the results are summarized, and the quality of evidence is formulated. If the effects are uncertain, or if the question cannot be answered from existing research, a knowledge gap is present. The identification of such gaps is important because they indicate the necessity of new research. Ethical and health economic aspects should also be integrated in a comprehensive, systematic review.