Results of endodontic retreatment: a randomized clinical study comparing surgical and nonsurgical procedures

Information of "success" rates after surgical or nonsurgical endodontic retreatment is abundant but inconclusive. Reported healing frequencies vary between 45% and 90%. The present study was designed to find any systematic difference between the methods. Nonsurgical and surgical retreatment was randomly assigned to 95 endodontically "failed" cases. The outcome of the procedures was clinically and radiographically recorded, and followed for 4 years. At the 12-month recall, a statistically significant (p < 0.05) higher healing rate was observed for cases surgically retreated. At the final 48-month examination, no such difference was found. These findings may be explained by (a) slower healing dynamics in the nonsurgical group and (b) the event of late "failures" in the surgical group. Within the latter category, four cases classified as healed after 1 yr failed at the final follow-up. Conclusively, this study failed to show any systematic difference in the outcome of surgical and nonsurgical endodontic retreatment. Surgical retreatment seems to result in more rapid periapical bone fill, but also may imply a higher risk of "late failures." From a scientific point of view, the length of the follow-up period is very important and may strongly influence the conclusions made.