ABSTRACT
Although outcomes of endodontic treatment have been of interest for many years, there is an apparent disparity between the success rates reported by cross-sectional studies (31-60%) and those of longitudinal studies (85-95%). Much of the published data have been gleaned from retrospective, nonrandomized cohorts. Ideally such studies would be conducted prospectively and the factor of interest randomized. For ethical and practical reasons, this is generally not possible. There are several possible explanations for the discrepancy in outcomes, such as variation between studies in terms of sample size, definition of success, treatment procedures, recall rate, length of observation period and radiographic interpretation. In this respect, the conclusions drawn from original historical data may be biased. More recently, metaanalysis and systematic reviews have been used to assimilate the data provided by multiple studies and will hopefully improve the body of evidence available for clinical use.
