This case report describes a case of intention replantation in a 15-year-old patient with a mandibular permanent right second molar that had undergone root canal treatment previously. The tooth was tender on percussion. Radiographic evaluation showed the presence of a separated instrument and periapical radiolucency. The surgical procedure was performed under local anesthesia, and the tooth was extracted. After cleaning and disinfecting the root canal system, the tooth was reimplanted, and the socket was filled with a mixture of bone graft material and a growth factor. A stainless steel crown was then placed to protect the tooth. A follow-up examination was performed after 12 months. The clinical and radiographic examinations revealed a well-healing periapical lesion with no signs of infection. The patient was asymptomatic, and the tooth was functional. The results of this case indicate that intentional replantation can lead to a favorable outcome.