In Vivo Comparative Study of Two Injectable/Moldable Calcium Phosphate Bioceramics

Calcium phosphate bioceramic granules associated with hydrosoluble polymers formed putties currently more used in clinical applications as they are easy to handle (injectability, moldability). In this study, 2 kinds of materials were tested in rabbit bone defects. The first one is In'Oss (TM) (Biomatlante), a microporous biphasic CaP granules (BCP, HA/TCP mixture) with polysaccharidic hydrogel; and the second one is Actifuse ABX (TM) (Baxter/Apatech), pure hydroxyapatite granules containing silicate (HA-Si) with blocks copolymer hydrogel (poloxamer),. The aim of this study was to compare osteogenic properties of two kinds of CaP putties containing HA-Si versus BCP and the kinetic of resorption of their hydrogel. Data have demonstrated that both hydrogels increase the handling properties. Bone regeneration was observed in the two types of sample, however at 3 weeks, Actifuse ABX hydrogel was not totally absorbed, while In'Oss hydrogel was no longer observed. The second difference observed was osteoconduction. Newly formed bone over the time period studied was moreover in close contact with BCP granules than with HA-Si granules. Larger granules resorption on time was observed for BCP compared to HA-Si. Resorption of Actifuse ABX remains limited and explains the faster kinetic of absorption for In'Oss. This study demonstrates biocompatibility, absorbability and bone ingrowth at the expense of the two types of putty injectable/moldable bioceramic used for bone regeneration.