Data sources: PubMed/Medline, Embase and The Cochrane Library databases.

Study selection: Clinical studies with a minimum sample size of 20 teeth and six months follow-up period, providing clinical and radiographic assessment of success/failure were considered.

Data extraction and synthesis: Three reviewers selected the studies and assessed study quality. Weighted pooled success rates and 95% confidence interval (CI) estimates of the outcome were calculated and a random-effects meta-analysis was carried out.

Results: Eighteen studies involving 2373 patients were included. Eleven studies (1175 patients) considered microsurgery; four of these were RCTs, three prospective studies and four retrospective. Seven studies (1198 patients) addressed endodontic retreatment; six of these were prospective studies and one retrospective. There was a statistically significant difference between the weighted pooled success rates for the microsurgery group and retreatment group. This was apparent in all follow-up periods except those greater than four years.

Conclusions: The authors concluded that based on this study, endodontic microsurgery was confirmed as a reliable treatment option with favourable initial healing and a predictable outcome. Further long-term clinical studies investigating endodontic microsurgery and retreatment are needed in the future.