Apexification with calcium hydroxide is associated with certain difficulties, such as the very long treatment time required, the possibility of tooth fracture, and incomplete calcification of the bridge. Use of an apical plug is an alternative treatment for open apices, and this has gained popularity in recent years, employing mineral trioxide aggregate (MTA) for optimal results. Here we report the successful treatment of two maxillary central incisors that had open apices and periapical lesions using MTA apical plugs after the root canals had been debrided and rinsed with 2.5% NaOCl. Calcium hydroxide paste was then placed in the canals for 1 week, before the apical portion of the canals (5 mm) was filled with the MTA plug. The remaining portion of the root canal was then sealed with a post and crown. After 6 months of follow-up, the clinical and radiographic appearance of the teeth showed a decrease of the periapical lesions. At 2 years, although the left post had been lost and the periapical lesion of the left central incisor had subsequently deteriorated, the right central incisor had healed successfully. Considering the importance of a coronal seal, the use of MTA for apical plugging appears to be a valid option. (J. Oral Sci. 49, 325-329, 2007)