ANGIOGENIC BEHAVIOUR OF CALVARIA AND ILIAC CREST BONE GRAFTS

Objectives: The aim of the study was to investigate angiogenesis occurence, by analyzing MMPs and VEGF expression, after autologous extraoral bone grafts from two different donor sites: calvaria and iliac crest. Methods: Calvaria and iliac crest bone grafts were used to recreate adequate bone volumes in the posterior maxilla before implant therapy. Specimens from the donor sites were withdrawn from regenerated sites four months after grafting (T1) and compared to bone biopsy obtained at the moment of grafts insertion (T0). Samples at different experimental times were processed in order to investigate MMP2, MMP9 and VEGF expression by immunohistochemical analysis. Results: Immunohistochemical analyses showed MMP2, MMP9, VEGF expression at T0 was higher in samples from iliac crest than in calvaria ones, while in T1 the levels of the investigated molecules were significantly higher in samples from calvaria bone graft than in those regenerated with iliac crest bone graft. Moreover, in both samples all the investigated molecules showed higher levels of expression in T1 than in T0. Conclusions: Autologous extraoral bone grafts are considered suitable biomaterials for pre-prosthetic regenerative techniques, according to their good clinical features and to the elevated success rate associated with their use. In this study, the capability of host tissue to initiate graft revascularization was investigated by analyzing changes in expression of molecules specifically involved in this important phase, like the MMPs and VEGF. Their expression increase after four months from the grafting, that is at the moment of implant insertion, for both investigated graft, but they resulted significantly more expressed in calvaria bone grafts, indicating a more rapid and intense angiogenic and regenerative response of this graft