The present case is about a 39 year old female patient, with no relevant medical history who attended the SERODU dental clinic, Quito-Ecuador, at the clinical examination an increase in volume was observed in the periapical region of the dental organs No. 11 and 12, on palpation it was determined the presence of a soft consistency swelling that apparently would be affecting the integrity of the bone tissue, she did not present any symptomatology. Pulp vitality tests were negative. The radiographic examination showed a radiolucent shadow compatible with a chronic periapical lesion affecting teeth Nos. 11 and 12. The aim of this study is to present a case in which after the failure of endodontic treatment a cystic lesion was observed in the periapical area. Therefore, it was decided to perform periapical surgery with apicoectomy of teeth No. 11 and 12, retrograde apical sealing and bone grafting.