Clinical and radiographic outcomes of non-surgical retreatment of mature maxillary incisions using two regenerative endodontic techniques in adolescents: a 24-month randomized clinical trial.

Aims: The primary aim was to monitor the healing of the periapical radiolucencies of adolescents' mature permanent teeth with apical periodontitis after root canal retreatment with two REPs techniques at 24 months of follow-up. The secondary aim was to assess clinical outcomes and positive responses of retreated teeth to pulp sensibility tests.

Methodology: Forty adolescents with 48 teeth were enroled and randomly allocated into two equal groups after being matched according to their periapical index (PAI) scores. Root canal retreatment was performed with blood clot (BC) formation in one group and platelet-rich fibrin (PRF) in the other group. The healing process was tracked using standardized two-dimensional radiographic images to record the changes in the PAI scores after 3, 6, 12, and 24 months. Additionally, the clinical signs and symptoms and the positive responses to pulp sensibility tests were monitored. The difference between the PAI medians was analysed using the Mann-Whitney U test. The main impact of time on the PAI values and the interaction between time and the REPs technique were assessed using the general linear model (GLM). The alpha level of significance was 5%.

Results: After two years of follow-up, there was no significant difference between the two groups clinically and in the PAI medians. The overall success rates in the BC and PRF groups were 95% and 100%, respectively (P > 0.05). Positive pulp responses were detected in 71% of the BC group and 73% in the PRF group (P > 0.05). The EPT mean values in the BC and PRF groups were 40.86 ± 6.60 and 37.9 ± 15.22, respectively (P > 0.05). Time had a significant impact on the PAI scores over the follow-up periods (P > 0.0001), while the interaction effect of time with the REPs technique had no significant effect on the PAI scores (P = 0.126).

Conclusions: REPs were effective in the retreatment of mature maxillary permanent incisors with apical periodontitis with a comparable reduction in the periapical radiolucencies and clinical outcomes associated with approximately similar positive responses to thermal and electric pulp tests.