This case study reports the successful treatment of an immature upper premolar with periapical pathosis and sinus tract using revascularization technique. Clinical and radiographic examination demonstrated the recovery of vitality, continued root development, and periapical healing at the 7-month follow-up. In addition, severe calcification of the canal was noted at the 36-month follow-up. At the 66-month follow-up, cone-beam computed tomography (CBCT) revealed complete periapical healing, apical closure, increase in root length and thickness of dentin, and severe calcification of the root canal. Even though the nature of tissue within the root canal is unknown, revascularization appears to give good clinical and radiographic success. This case report highlights that severe calcification of the canal is one of the long-term outcomes of revascularized root canals.