[Biomaterials and osseous regeneration].

The autologous bone graft is commonly used for the repair of bony defects, but its resorption is unpredictable, and there is an inherent morbidity of the donor site. There is a wide range of biomaterials that could be used as bone substitutes, depending on their bioactivity. Among bioactive materials, bioglasses present a linkage between their reactive surface and the adjacent bone although they cannot be colonized by bony ingrowth, moreover their fragility and resorption as particles limit their use. The osteoconductive biomaterials are either represented by the synthetized ceramics, such as hydroxyapatite (HA) or tricalcium phosphate (TCP), or either natural coral and the derived biomaterials of bony matrix. Coral exoskeleton or TCP are highly resorbable, but pure HA is only slightly. Bony ingrowth in osteoconductive materials is limited to the periphery of the implant which does not make it suitable for the repair of large defects. Research is focused on the adjunction of a biologically active substance to the osteoconductive matrix in order to enhance bony ingrowth. Osteoinductive materials such as bone growth factors in combination with a carrier can promote bone healing, especially when bone morphogenetic protein (BMP) is used. Nevertheless, even if their efficacy is demonstrated, their inocuity has not been totally confirmed. Furthermore, the dose used are far superior than in the physiological pathways. Hybrid biomaterials combine an osteoconductive carrier with bone marrow cells. Bone cell cultures could amplify to almost any extent the number of osteogenic cells for such a biomaterial. Bone substitutes will certainly be used in the future to repair bony defects.