A critical appraisal of evidence-based dentistry: the best available evidence

The principle of evidence-based dentistry requires that relevant scientific literature be integrated into the dentist's practice and the patient's treatment needs and wishes. This approach involves critically appraising the scientific literature for the best available evidence in order to make clinical decisions.

The purpose of the study was to critically appraise the process by which a practitioner attempts to make an evidenced-based clinical decision. This process is illustrated by evaluating the clinical literature pertaining to zirconia-based single crowns.

An electronic search was performed in PubMed and the Cochrane Library by using Boolean operators for articles published in English between January 1950 and October 2012 to address the PICO (patients, intervention, comparison, outcome) question, "In adults, how does the long term prognosis of zirconia-based single crowns compare to conventional single crowns on natural teeth?" Comparisons were made across the publications to determine the quality of relevant information.

Three systematic reviews included 4 clinical trials. Two randomized clinical trials and 1 retrospective study met the search criteria but were not identified in the systematic reviews. The definitions of the outcomes and the presentation of the data varied among studies.

The lack of standardization of reporting data, the nonstandardized definitions of outcomes, and the impact of the length of the research study were identified as problems that need to be addressed to improve the quality of systematic reviews and other clinical trials.