Evaluation of bone regeneration obtained with equine- and swine- derived bone substitute

Introduction: The aim of this study was to investigate, by morphological and immunohistochemical analyses, the in vivo bone regeneration obtained through a resorbable equine-derived particulate biomaterial (M1) and swine commercial bone substitute (M2) as grafting in sinus augmentation procedures. Methods: M1 and M2 were used as bone substitute in sinus augmentation procedures, in patients requiring implant insertion in the distal upper maxilla. Specimens from the regenerated sites were withdrawn at the moment of implant insertion, six months after grafting. Samples underwent light microscope observation. Then, immunohistochemical analyses were performed to assess expression of VEGF and Bone Sialoprotein (BSP). Results: At light microscope observation, both the investigated bone substitutes showed a good integration with the host tissue. However, graft particles were entirely evident in M2 group while evident sign of particles resorption could be recorded in specimens from M1. Immunohistochemical analyses showed VEGF expression was higher in m1 than in M2 samples. WHILE BSP was over-expressed in m2. Conclusions: These results showed that both grafts have a close integration with the host tissue, associated with a comparable clinical performance, indicating they can be successfully used in pre-prosthetic regenerative procedures. However, at the same experimental time, after six months, specimens from M1 exhibit evident resorption phenomena, while no or few signs of resorption were evident in M2. In addition a better revascularization was achieved in m1 samples as showed from higher expression of VEGF. Even if the different in vivo behavior seemed not to affect clinical performance of the bone substitute, the characteristic to be resorbed may affect long term integration and long term predictability of implant-prosthetic rehabilitation.