Study On Preparation And Properties Of Dicalcium Phosphate Dehydrate Cements Prepared Using Hydroxyapatite(HA)/Monocalcium Phosphate Monohydrate (MCPM)

Dicalcium phosphate dihydrate (brushite or DCPD) bone cement is a kind of very attractive biological bone repair materials and a number of different bone cement formulations have been put forward. In this study, specifically compared HA/MCPM and β-TCP/MCPM systems through to test physical and chemical properties of bone cement, degradation properties, biomineralization properties and biocompatibility is affected due to the difference in reactants. Using a simple model for testing in vitro, we found that the β-TCP/MCPM system degraded mainly with dissolution mechanism, which was associated with slightly pH drop and the mass loss of relatively low quality. Cytocompatibility tests, extract cultured osteob lasts revealed no significant change in cell viability. In contrast, HA/MCPM system were prone to undergo rapidly of DCPD to HA, leading to a sharp in pH drop and resulting in a large number of quality mass loss. But for the cell activity, the HA/MCPM system effect was not significant. Overall, these results suggest that although the product of the setting reaction is the same, the HA/MCPM system and β-TCP/MCPM system, differ significantly in their degradation properties and cytocompatibility. These differences are very important for clinical application. HA/MCPM system is to test the hemolysis and to implant it into the bone defect as the composite materials.10healthy adults New Zealand rabbits were randomly divided into3groups, all around established bilateral mandibular bone defect model in the experiment, the right bone defect of the group implant HA/MCPM materials, on the left side of the implanted no repair material, as blank control. With X-ray slice observation, histological observation to evaluate ability of HA/MCPM. The experimental material of the leaching solution in rabbit blood has no hemolysis phenomenon. In implant test, animals have no allergy, infection, other adverse reactions, no death, so it has good compatibility; X-ray and histological observation showed that the blank control group was no new bone formation and bone defect had not been repaired. In the experimental group,4weeks, the material started degradation, ambiguous is irregular; in9weeks, the implant materials is absorbed and most were degradated in defect area, and the new bone substitution; in12weeks, the material has been largely degradation and trabecular bone defect parts connected at the same time, meanwhile lamellar bone formation and new bone completely fill the bone deficiency.In general, the HA/MCPM system has compatibility in animals. Material is biodegradable and can promote more new bone ingrowth. The preparation of DCPD bone cements has good degradability, osteo-conductive and osteo-induction, moreover significantly accelerated the process of bone repair. This material can make better bone repair completely, has good histocompatibility, suitable for mandibular defect repair, and it is a kind of good bone repair material. So the HA/MCPM system DCPD is expected to become a good clinical bone repair materials.