Evaluation Of Bone Regeneration Obtained With Autologous Or Heterologous-Deproteinized Bone

Objectives: The aim of this study was to investigate the different behaviour of autologous bone (AB) and heterologous-deproteinized bone (HDB) as grafting in pre-prosthetic bone regenerative procedures. AB was obtained from calvaria (ABc) and mandibular ramus (ABm), while HDB was swine commercial bone substitute. Methods: AB and HDB were used to fill bone defects in edentulous sites, in patients requiring implant insertion. Specimens from the regenerated sites were withdrawn at the moment of implant insertion, six months after grafting.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, procollagen I, bone sialoprotein (BSP), iNOS and Bax. Finally, TUNEL analysis was conducted to measure the main number of apoptotic cells in the different samples. Results: At light microscope observation, the investigated bone substitutes showed a good integration with the host tissue. Immunohistochemical analyses showed VEGF expression was higher in ABc than in ABm and HDB. In ABm samples, BSP was over-expressed while iNOS appeared down-expressed compared to ABc and HDB. Procollagen I and Bax resulted highly expressed in HDB compared to AB samples. TUNEL analysis showed high number of apoptotic cells in HDB samples. Conclusions: Clinically, all the grafts appeared integrated with the host tissue, indicating they can be successfully used in pre-prosthetic regenerative procedures. However, after six months, specimens from HDB grafting exhibit remaining resorption phenomena, demonstrated by the over-expression of Bax and by the presence of high quantity of procollagen I. Presence of diffuse apoptotic cells in HDB samples was confirmed by TUNEL analysis. In contrast, higher ossification, forwarding neoangiogenesis and lesser inflammation could be observed in AB grafting