Long-Term Evaluation of Maxillary Reconstruction by Iliac Bone Graft

By light microscopy, T-1 samples showed well-organized osteoblasts and extracellular matrix (ECM), and surrounding areas of connective tissue where a discrete number of blood vessels can be distinguished. Samples obtained from reconstructed areas after a long period of follow-up (T-2) were characterized by uniform mineralized ECM with cavities containing osteocytes, whereas T-0 samples disclosed both mineralized matrix and bone marrow. Matrix metalloproteinase 2 (MMP-2), vascular endothelial growth factor (VEGF), inducible nitric oxide synthase (iNOS), and bone sialoprotein (BSP) expressions were investigated by immunohistochemical analysis. Both MMP-2 and VEGF showed significantly increased expression in T-1, with respect to T-0, and lowered in T-2. Otherwise, BSP expression, which was elevated in native iliac crest bone (T-0), was deeply decreased in T-1 and T-2 samples. Moreover, changes in iNOS expression and in apoptotic cell nuclei percentages (TUNEL analysis) seemed to have a similar trend, increasing in T-1 and lowering in T-2.

The aim of this study was to analyze histologic and immunohistochemical modifications taking place in maxillary sites reconstructed by iliac crest bone grafts, 4 months (T-1) and 10 years (T-2) after grafting, in comparison to native iliac crest bone (T-0).