Mandibular defect reconstruction remains a clinical challenge, necessitating an optimal grafting material to restore function and aesthetics. This randomized controlled trial compared the efficacy of autogenous bone grafts and alloplastic materials in mandibular defect reconstruction. A total of 60 patients with segmental mandibular defects were randomized into two groups: Group A (autogenous bone grafts) and Group B (alloplastic materials). Clinical and radiographic assessments, including graft integration, bone resorption, and functional recovery, were performed at 3, 6, and 12 months postoperatively. The results demonstrated that autogenous bone grafts exhibited superior graft integration and bone volume retention (p < 0.05), whereas alloplastic materials showed increased postoperative complications, including delayed osseointegration and graft failure. However, alloplastic materials provided a viable alternative in cases where autogenous bone harvesting was contraindicated. These findings highlight the advantages and limitations of each approach, emphasizing the need for patient-specific treatment planning. Further long-term studies are warranted to refine reconstructive protocols and optimize patient outcomes.