The iliac crest graft is considered the best option for reconstruction of large mandibular defects due to its abundant corticocancellous bone, large volume, and excellent osteogenic potential. This graft provides structural support and allows for easy shaping to match the mandibular contour. Additionally, it offers a high success rate in vascularization and integration with the mandibular site. Unlike other grafts, the iliac crest provides a thinner cortex and more cancellous bone, promoting faster revascularization and better incorporation, essential for large defects. Its donor site morbidity is acceptable compared to other options providing similar bone volume.

Reference: Contemporary Oral and Maxillofacial Surgery, James R. Hupp, 7th Edition.