ABSTRACT
A 25-year old female was referred with gingival recession and pus discharge associated with bony dehiscence in relation to previously root canal treated maxillary left lateral incisor. Radiographic examination revealed presence of a second canal which was left untreated in the previous treatment which could be the possible cause of treatment failure and development of bony dehiscence. During re-treatment, the second canal was located, cleaned and shaped and obturated and the bony defect was treated with free gingival graft. This case report demonstrates the need for greater attention in treating the root canal of maxillary lateral incisors due to its variations in root canal morphology and also the need for thorough evaluation of good quality pre-operative radiographs taken in different angulations to avoid such mishaps. This case is unusual because considerable research has reported that these teeth can only have a single canal.