Ruolo delle superfici implantari nel processo di osteointegrazione.

Role of implant surfaces in the osseointegration process The aim of the present study was to evaluate the interactions between titanium implant surface and biological environment by a review of the recent literature about cellular and molecular mechanisms on which osseointegration relies. The bone matrix deposition on implant surface and its mineralization is just the last stage of a complex sequence of events to date not completely understood. Osseointegration is similar to the «scar free» healing process of a bone fracture. The implant site creation produces a vascular interruption into the bone and the soft tissues. This leads to a bleeding phenomenon and causes a tight contact between the host biological fl uids and the external layer of the implant surface. The following events are clot organization, neoangiogenesis and recruitement, migration and diff erentiation of osteogenic cells. At the end of this sequence of events it will occur the deposition and successive mineralization of bone matrix. Matrix deposition could take place directly on the implant surface, in this case the process is called «contact osteogenesis» or, on the contrary, it could begin by the peri-implant bone walls, leading to a so called «distance osteogenesis». New implant surfaces are aimed at promote early stage of «bone healing» process, inducing migration and colonization of the fi xture by osteoprecursors.