The aim of the present report is to describe the unusual finding of mineral trioxide aggregate's (MTA) disappearance from the root-end cavity, several years after successful periapical surgery and complete wound healing. A 32-year-old male patient was referred by a general practitioner for root canal treatment of the right maxillary central and lateral incisors with a sinus track and a large periapical radiolucent lesion. After completion of the root canal treatment, endodontic surgery was performed since symptoms persisted. The retrograde cavity of the lateral incisor was sealed with MTA and the patient was monitored in the subsequent years, in order to evaluate the surgical outcome. Recall examination after 4 months revealed absence of signs and symptoms and reduction of the radiolucent lesion, indicating normal healing. After 2 years, the follow-up radiographic examination revealed further healing of the periapical lesion, with the MTA apical retrograde filling remaining in its place but with signs of disintegration. However, follow-up radiographic examination after 7 years revealed that the former radiolucent area is diminished and the root apex is completely covered by normal periodontal ligament and alveolar bone, whilst the retrograde filling is not visible at all, possibly due to disintegration. Long-term follow-up of apicoectomy cases is mandatory and further research is deemed necessary for the long-term evaluation of MTA, when in contact with periapical and periodontal tissues. Keywords: endodontic surgery, follow-up, MTA dissolution, periapical healing