Implants osseux

NOVELTY - The bone substitute is made in one piece from cement phosphocalcium materials consolidated chemically at low temperature and in presence of water. USE - In medicine, as artificial bone graft. ADVANTAGE - Macroporous structure promotes resorption of the substitute while ensuring the best initial mechanical properties and their preservation until the graft is replaced by the newly formed bone. DETAILED DESCRIPTION - Bone substitute is made in one piece from cement phosphocalcium materials consolidated chemically at low temperature and in presence of water. The substitute has at least one elongated interstice of approximately constant cross-section and preferably contains at least one main network system (I) and optional second system (II) of parallel canals, with canals of system (II) preferably connecting the canals of system (I). The latter have cross-section 8 x 10-3 - 0.8 mm2, preferably 0.1-0.3 mm2, while the canals of system (II) have cross-section 3 x 10-3 - 8 x 10-3 mm2. The volume of interstice(s) amounts to 10-70 (preferably 30-60) vol.% of bone substitute whose total porosity amounts to 28-88%. INDEPENDENT CLAIMS are also included for: (1) cement for bone substitute as claimed, made of liquid/plastic paste comprising one or more calcium phosphates and at least one other hardly soluble calcium salt, e.g. sulfate, pyrophosphate or carbonate; and (2) process of making bone substitute as claimed, with chemical consolidation of cement conducted ex-vivo, either at ambient medium and temperature, or at water-saturated medium and elevated temperature, and with anatomical geometry of shape and macroporous structure obtained during forming by molding of phospho-calcium paste and by chemical consolidation, while interstice(s) are made with polymer threads (of nylon, PVB or polyethylene). The process uses rapid prototype mode such as stereolithography, or wax-jetting, to produce the mold and porogenous phase.