a case of successful retreatment of a maxillary lateral incisor with a supernumerary root

knowledge about the morphology of the root canal system is a pre-requisite for achieving a successful outcome in root canal treatment. in this report, a patient with a maxillary lateral incisor which had previously undergone orthograde endodontic retreatment for two times is discussed. the tooth had been misdiagnosed with a palatal groove or a root fracture, its prognosis had been determined to be poor and extraction was advised by a practitioner. during our evaluation, an unrecognized supernumerary root and root canal were detected and the tooth was maintained successfully with orthograde endodontic retreatment. the use of cone beam computed tomography (cbct) and magnification were of significance in the treatment process of this case.