Aim

To evaluate the outcome of surgical retreatment at four time points, i.e., 6, 12, 24, and 48 months postoperatively, and to search for prognostic factors that may affect the outcome.

Methodology

Clinical records and intraoral periapical radiographs were collected from patients who had undergone surgical retreatment between 2009 and 2015 and attended 6, 12, 24, and 48 month follow-up visits. Surgical retreatment was performed by one endodontist and involved minimal root-end resection and maximal length root-end preparation using prebent ultrasonic files. Outcomes were categorized as complete, incomplete, uncertain, or unsatisfactory healing, based on clinical and radiographic findings. The complete and incomplete categories were pooled and considered successes, while uncertain and unsatisfactory outcomes were considered failures. Changes in healing outcome were analyzed using the McNemar-Bowker test and prognostic factors were analyzed using univariate analysis.

Results

The study cohort included 297 patients with 384 teeth. The overall success rate after 48 months was 90.6% compared with 88.5%, 93%, and 92.4% after 6, 12, and 24 months respectively. Age, gender, presence of isthmus, and length of canal preparation had no significant influence on the outcome. Lesion size and tooth type had a significant influence only after 6 and 12 months respectively, with no significant differences at other time points. Fifty percent of the teeth classified as unsatisfactory or uncertain healing at the 6 months follow-up, improved to incomplete or complete healing after 12 months. None of the cases classified as unsatisfactory healing after 12 months subsequently improved, and only 2 cases that were classified as uncertain healing after 12 months, improved after 24 months.

Conclusions

Surgical retreatment was found to be a predictable procedure with a high success rate of 90.6% after 4 years. Over the follow-up periods only a minor regression in the success rate was found. The 12 months follow-up results closely indicated the long-term outcome of surgical retreatment.