Long-term Outcomes and Prognostic Factors in Surgical Endodontic Retreatment: A Retrospective Cohort Study

Background Persistent apical periodontitis following failed nonsurgical endodontic treatment presents significant clinical challenges. This study evaluated the long-term outcomes and prognostic factors associated with surgical retreatment using calcium-enriched mixture (CEM). Methods In this retrospective cohort study (STROBE-compliant), 197 teeth from 169 patients underwent surgical retreatment at a tertiary center between 2011 and 2024. Inclusion required documented persistent apical periodontitis unresponsive to prior orthograde endodontic therapy and a minimum radiographic follow-up of 6 months. A standardized microsurgical protocol was followed, including root-end resection, ultrasonic root-end preparation, and root-end filling with CEM cement by a single endodontist. Treatment outcomes were assessed using composite clinical and radiographic criteria. Kaplan–Meier analysis was used to estimate survival probabilities, and Cox proportional hazards regression was applied to evaluate associations between clinical variables and treatment outcomes. Results The mean follow-up duration was 45.2 ± 36.5 months. The overall success rate was 94.9% (187/197 teeth). Failure-free survivals were 96.4%, 92.7%, and 87.3% at 1, 3, and 5 years, respectively. Multivariate analysis identified systemic disease as the sole significant predictor of failure (HR = 5.87; 95% CI: 1.52–22.68; p = 0.010). Tooth-related factors (lesion size, crown-root ratio, and root-end preparation depth) and demographic variables showed no significant associations. Intra-observer agreement was excellent (κ = 1.00; ICC = 0.83). Conclusions CEM cement-based surgical retreatment achieved 94.9% long-term success. Patients with systemic diseases exhibited a 5.87-fold higher failure risk, highlighting the critical role of medical status in prognostic assessment.