Periapical Lesion Size and Regenerative Materials as Prognostic Factors in Endodontic Microsurgery: A 12-Month Retrospective Cohort Study.

OBJECTIVE: This study evaluated the influence of initial periapical lesion size and the use of bone graft and/or membrane materials on endodontic microsurgery outcomes, considering other clinical factors. METHODS: A retrospective cohort study included 127 teeth treated with endodontic microsurgery, with or without adjunctive bone graft and/or membrane placement, between January 2021 and December 2024. Based on the initial Periapical Index (PAI) scores, patients were classified into 2 groups: small lesions (PAI ≤3) and large lesions (LL, PAI ≥ 4). Treatment outcomes were assessed at 12 months according to established criteria. Statistical analyses included chi-square or Fisher's exact tests, t-tests and multivariate logistic regression (P < .05). RESULTS: The overall success rate was 64.6%. The use of bone graft and/or membrane was associated with significantly higher success rates (72.0% vs. 53.8%; odds ratio [OR]=2.34, 95% CI: 1.10-4.98; P=.03), particularly in LLs (69.6% vs. 42.3%; OR=2.90, 95% CI: 1.08-7.78; P = .03). In multivariate analysis, regenerative material use (adjusted OR=2.48, 95% CI: 1.12-5.50; P=.03) and anterior tooth position (adjusted OR=2.71, 95% CI: 1.24-5.93; P=.01) were significantly associated with treatment success. CONCLUSION: Within the limitations of this 12-month retrospective cohort study, the adjunctive use of regenerative materials and anterior tooth position were associated with higher success rates in endodontic microsurgery. Preoperative lesion size alone was not significantly associated with treatment success.