Injuries to the dentition may ultimately result in the interruption of root development. If the pulp remains vital following trauma, this state should be maintained and root-end closure should be induced by apexogenesis. When the pulp is necrotic, the placement of an apical barrier can be utilized as an alternative to establish an environment that facilitates the closure of the apical opening. This article demonstrates the use of mineral trioxide aggregate as an apical barrier material for root-end closure in the permanent teeth of three patients.