Large endodontic lesions do not resolve solely by root canal therapy. Additionally, surgical intervention is required to eliminate the lesion completely and relieve the patient’s symptoms. Dental trauma is the leading cause of loss of tooth vitality in children. It often leads to the presence of immature open root apices, which should be dealt with at an early stage to prevent periapical infections. Surgical removal of a large periapical granuloma was done, followed by, retrograde apical filling with mineral trioxide aggregate, for an immature maxillary central incisor in an apexification procedure.