Study On Porous Biodegraded Cementing Material For Osteo-inductivity

This topic firstly put forward a method that metal implant was used with biodegradable osteoinductivity material. The purpose was that biodegradable material filled the hole of metal implant, inducted bone tissue growth, prevented parenchyma growth and carried out firm mechanical fix of implant in bone.Choose appropriate biodegradable material was the key of study. In this thesis, degradable calcium-phosphorus was prepared by a new process that α-TCP bound β-TCP powder combining with H2O2 making holes. β-TCP was a good biodegradable material which component was similar to bone as the most important characteristic. In addition to good biocompatibility, the material could induct bone growth but itself absorbed or excreted with metabolism in body, which avoided the hidden trouble of material long-term existence in body. The slurry of bioactive bone cement was easy to model, could solidify by itself and had appropriate mechanism performance. The preparation of cementing composite that hydrated bioactive bone cement bound β-TCP could proceed under normal temperature, avoided sintering and model complicated sample with proper strength. HAP from bone cement hydration and β-TCP constructed bi-phase porous ceramic.Optimum proportion of α-TCP and β-TCP was 1:1 through experiments. The pore made by H2O2 is affected by concentration of H2O2. Pore size increased with higher concentration and ideal pores were attained when concentration of H2O2 reached to 15%.During pore creation, temperature and heating time had great effect on porous structure and strength of system. In experiment, 150℃ and thermal insulation for 5~ 10 min could make preferred pore and give material certain strength. Maintenance which can make bone cement hydrate completely and effectively improve strength was necessary to cementing system and 24h maybe enough.Three-dimension microscope, XRD, SEM and IR were used to analyze structure and performance of material prepared by new process. The result indicated that β-TCP didn't affect hydration of a-TCP, the product of a-TCP hydration was apatite and HA appeared chrysanthemum-like crystallization. The process of H2O2 making holes didn't induct any impurity and could make porous structure with connectivity.The formation of the bone-like apatite containing carbonate in the calcium phosphate ceramics was important to the growth of the new bone and the osteoinductivity of materials. This thesis discussed that formation and effect of bone-like apatite on porous calcium phosphate ceramics in SBF through exoteric experiment. The result indicated that the ability of new crystal formation was different from pore size of porous calcium phosphate ceramics. The bone-like apatite could be formed in shorter time in this ceramics for the carbonate mixing into the structure of the apatite crystal. The formation of the bone-like apatite was greatly affected by surface property and velocity of ion-exchange.