Outcome of primary root canal treatment: systematic review of the literature – Part 1. Effects of study characteristics on probability of success

The estimated weighted pooled success rates of treatments completed at least 1 year prior to review, ranged between 68% and 85% when strict criteria were used. The reported success rates had not improved over the last four (or five) decades. The quality of evidence for treatment factors affecting primary root canal treatment outcome is sub-optimal; there was substantial variation in the study-designs. It would be desirable to standardize aspects of study-design, data recording and presentation format of outcome data in the much needed future outcome studies.