Histopathological patterns of periapical lesions in root canal treated teeth: A systematic review

INTRODUCTION. Periapical lesions are common sequelae of pulpal necrosis and endodontic infections, presenting significant diagnostic challenges in clinical practice. Accurate histopathological characterization is essential for appropriate treatment planning and prognostic assessment. AIM. To systematically evaluate and summarize the histopathological features, prevalence patterns, and diagnostic concordance of periapical lesions in root canal treated teeth. MATERIALS AND METHODS. A systematic review was conducted following PRISMA 2020 guidelines. Electronic databases including PubMed, Scopus, Web of Science, and Google Scholar were searched for studies published between 2000–2024. Inclusion criteria encompassed histopathological studies of periapical lesions from root canal treated teeth. Quality assessment was performed using the Newcastle-Ottawa Scale and QUADAS-2 tools. RESULTS. Twelve studies involving 1,847 periapical lesion specimens were included. Histopathological analysis revealed periapical granulomas as the most prevalent lesions (50–84.2%), followed by radicular cysts (15–42%) and periapical abscesses (5–35%). Clinical-histopathological concordance was poor, with overall agreement ranging from 51.4–55.8% (Cohen’s kappa κ = 0.059). Larger lesions (> 200 mm²) showed higher prevalence of radicular cysts (92–100%). Periapical scars represented 1–6% of cases. DISCUSSION. Significant discrepancies between clinical and histopathological diagnoses highlight limitations of radiographic assessment alone. Lesion size, location, and duration influence histopathological patterns. The predominance of granulomatous tissue suggests ongoing inflammatory processes despite endodontic intervention. CONCLUSIONS. Histopathological examination remains the gold standard for definitive diagnosis of periapical lesions. The poor clinical-histopathological concordance emphasizes the necessity of biopsy examination for accurate diagnosis and appropriate treatment planning in endodontic practice.