Contralateral Inferior Alveolar Nerve Transposition for Simultaneous Dental Implant Placement on a Unilateral Reconstructed Mandible: A Case Report With a 7-Year Follow-Up

Abstract

This case report describes an unusual case of implant treatment after contralateral inferior alveolar nerve transposition (IANT) on a unilateral reconstructed mandible due to gunshot trauma with a 7-year follow-up. The patient had an edentulous atrophic mandible and underwent large bone reconstruction on the left side. The irregular passage of the right inferior alveolar nerve was within 1-2mm of the superior aspect of the mandible, passed through the midline, and was nearly exposed under the oral mucosa at the left anterior part of the mandible, which prevented the placement of conventional implants. Consequently, right IANT followed by iliac onlay bone grafting was undertaken under general anesthesia to create a sufficient bone volume for implant placement. Four implants were installed simultaneously on the augmented bone. After a 2-month waiting period, soft tissue graft placement and vestibuloplasty were performed. The patient was scheduled for a continuous follow-up for the next 7years. After 3years, the bar-retained supporting system was replaced with the new CAD/CAM milled bar system on the same 4 implants. The 4 implants presented good initial stability (>35N/cm), and radiographic evaluation showed osseointegration around all 4 implants. The patient experienced lip numbness in the first 5days postoperatively but recovered by 97% after 2months. After a 7-year follow-up, the result remained satisfactory with no sign of bone loss around any of the 4 implants, and the prosthesis functioned well and was stable and esthetically satisfactory. In conclusion, an immediate implant placement procedure after a complex surgery involving unilateral IANT and iliac onlay bone grafting remains challenging, especially when the patient has extensive bone defects or an atrophic mandible. However, a successful long-term outcome can be achieved with appropriate perioperative and postoperative care.