An overfilled root canal is the most common iatrogenic error in daily endodontic practice, especially on open apex tooth, which leads to chronic periapical inflammation and failure of endodontic therapy. With various materials and techniques available, the clinician must determine the ideal protocol to ensure successful endodontic treatment. This case report evaluates the outcome of the non-surgical, one-visit apexification using Mineral Trioxide Aggregate (MTA) of first maxillary incisor with an overfilled root canal, open apex, and condensing osteitis after four years follow-up. A 27-years-old woman was referred to Universitas Gadjah Mada Dental Hospital Yogyakarta due to biting pain and discoloration on first maxillary incisor with a history of trauma and endodontic treatment over 10 years ago. Periapical radiographs showed an overfilled open apex with condensing osteitis on the surrounding of the apex. Conventional endodontic retreatment was performed, followed by one-visit apexification using MTA. After 6 weeks, the biting pain relieved. Obturation and intracoronal bleaching then proceeded. Class IV composite was completed as a final restoration after 8 weeks of apexification. After 4 years follow-up, there was no sign and symptom and the condensing osteitis diameter reduced which indicated a successful treatment. This case supports the long-term evidence of former findings of the role of case selection, technique, and usage of MTA as one-visit apexification materials after a year follow-up. Furthermore, it provides a new perspective on the effect of MTA in the management of condensing osteitis. One-visit apexification using MTA is considered effective in the management of condensing osteitis due to gutta-percha extrusion in the long term