The Clinical Outcomes of Non-Surgical Retreatment in Teeth with Persistent Apical Periodontitis: A Systematic Review

Abstract

This systematic review examined contemporary evidence on clinical and radiographic outcomes of nonsurgical endodontic retreatment for persistent apical periodontitis. A comprehensive search of five databases and grey literature sources from January 2000 to September 2025 was conducted following PRISMA 2020 guidance. Eligible designs included randomized trials, prospective and retrospective cohorts, and case–control studies that evaluated orthograde retreatment of permanent teeth with clearly defined clinical or radiographic outcomes and at least twelve months of follow-up for quantitative tabulation. Two reviewers independently screened records, extracted data in duplicate, and assessed risk of bias using ROBINS-I. Findings were synthesized narratively without statistical pooling and were grouped by outcome definitions, imaging modality, follow-up duration, and key clinical factors. Seventeen studies met the inclusion criteria. Most cohorts used periapical radiography at recall and reported both strict healed and lenient success endpoints. Strict healed proportions typically ranged from the mid-sixties to the low-eighties percent, while lenient success commonly ranged from the mid-eighties to the low-nineties percent. Studies that used cone beam imaging at follow-up reported lower strict healed proportions at comparable time points. Larger baseline lesions and posterior teeth were consistently associated with slower or reduced strict healing. Perforation and canal transportation were linked to poorer outcomes, whereas a definitive and adequate coronal restoration was associated with better results. Visit number showed no consistent association once case context was considered. Risk of bias was mostly moderate, with serious concerns concentrated in attrition, selection and confounding, and outcome measurement. In conclusion, nonsurgical retreatment delivers high clinical success and dependable tooth retention, complete radiographic resolution often requires extended follow-up in larger lesions and in posterior teeth, and technical excellence with reliable coronal sealing remains central to favorable outcomes.