A case of dens invaginatus in a maxillary lateral incisor with a periapical lesion (that was discovered by chance after a panoramic radiographic examination despite the abnormal anatomy) responded successfully to non-surgical treatment involving chemomechanical root canal preparation associated with longterm treatment with calcium hydroxide. Keywords: apexification, apexogenesis, crown fracture, dens invaginatus, immature root, MTA, pulpotomy, intracanal medication, peri-radicular lesion, root canal treatment