Objective: To evaluate the sealing capacity and retention of apical barriers made with mineral trioxide aggregate (MTA) and Portland cement (PC). Material and Methods: Fifty-six bovine incisors were sectioned 8 mm above and 12 mm below the cement-enamel junction. The root canal was enlarged with a diamond drill to create a standard 2.5 mm diameter opening. Apical sheets of 5 mm thickness were placed using white MTA-Angelus or white PC. Fifteen samples of each material were exposed to human

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... a in a dual chamber apparatus and casting was evaluated at 30 days. Samples without apical barriers and fully sealed samples were used as positive and negative controls (n = 3), respectively. Data were analyzed by Fisher's exact test (p<0.05) after 3 periods: 1 to 10 days (P1); days 11 to 20 (P2); and days 21 to 30 (P3). Then, three 1 mm thick sections were obtained at the apical level of other root samples of each material (n = 10) and the push-out test was performed. Results: The leakage rates in P1, P2 and P3 were 60%, 73.3% and 100% for the MTA; and 73.3%, 86.7% and 100% for CP, with no significant difference between materials, regardless of the period analyzed. There were no significant differences between the bond strengths for both cements (p>0.05). Conclusion: Mineral trioxide aggregate and Portland cement apical barriers presented similar sealing ability and bond strength values.