Root fractures are defined as fractures involving dentine, cementum, and pulpal and supportive tissues. They comprise about 0.5–7% of all dental injuries. Horizontal root fractures are commonly observed in the maxillary anterior region and 75% of these fractures occur in the maxillary central incisors. Case report: This case report is about a 26-year-old male referred to the endodontic department of Zahedan dental school 3 days after motorcycle accident. Radiographic examination shows a horizontally root fracture of the right mandibular central incisor in the apical third. Initially, the coronal fragment was repositioned and this was radiographically confirmed. Then, the stabilization splint was applied and remained for 50 days. Two weeks splinting which radiographic examination showed the lesion adjacent to the fracture line, the two visit endodontic treatment of the coronal portion was started and the root canal was obturated with gutta percha points. Conclusion: One-year follow-up examination revealed the clinical and radiographic signs of healing with hard tissue repair of the fracture line.