Objective <p>To evaluate clinical and radiographic outcomes of iRoot BP Plus apical barrier treatment in permanent teeth with open apices and periapical lesions and to explore associated factors.</p> Methods <p>Permanent teeth exhibiting pulp necrosis and open apices treated with iRoot BP Plus apical barrier were retrospectively included with follow-up ≥ 12 months. Treatment outcomes were determined through clinical examinations and radiographic assessments, with results classified as healed, healing, or failure. Quantitative changes in root length, root width, and apical diameter were measured on paired radiographs. Associations between baseline variables and outcomes were examined using chi-square or Fisher’s exact tests.</p> Results <p>A total of 54 teeth were included in the final evaluation, with a median follow-up period of 18.5 months (minimum 12 months, maximum 60 months). At final follow-up, 23 teeth (42.6%) were classified as healed, 29 (53.7%) as healing, and 2 (3.7%) as failure. Favorable outcomes (healed and healing) were observed in 52 teeth (96.3%); most teeth (52/54) were asymptomatic. Radiographs showed substantial reduction or resolution of periapical lesions. Periapical index (PAI) was significantly associated with treatment outcome (<i>P</i> &lt; 0.05). Quantitative radiographic measurements indicated increased root length and root width with a reduction in apical diameter during follow-up.</p> Conclusion <p>In this retrospective cohort, iRoot BP Plus apical barrier treatment showed favorable clinical and radiographic outcomes in permanent teeth with open apices and periapical lesions.</p> Clinical relevance <p>In this study, PAI was associated with treatment outcomes, which may help clinicians in case assessment and follow-up planning.</p>