Study On Inositol Hexaphosphate-Chelating Hydroxyapatite Bone Cement

Due to bone cement can be shaped according to the patient's bone defect and set under physiological conditions, it has been widely used as human hard tissue repairing and replacement materials in orthopedics, dentistry and plastic surgery.In this thesis, three kinds of chelating hydroxyapatite bone cement were prepared by mixing hydroxyapatite(HA) surface-modified by inositol hexaphosphate(IP6) with distilled water, citric acid(CA) solution and citric acid/chitosan(CA/CS) solution, respectively. X-ray diffraction(XRD), scanning electron microscopy(SEM) and universal testing machine were employed to investigate the influence of parameters including concentrations of IP6, CA and CS, as well as powder to liquid ratio on the properties of HA bone cement.The cured product of IP6-chelating hydroxyapatite bone cement was HA, which was not affected by the concentration of IP6 used in particle surface-pretreatment. When the IP6 concentration increased to 5000 ppm, the compressive strength of cured bone cement was above 30 MPa. Along with the increasing IP6 concentration, the heat output increased slightly during curing process, with a temperature rise less than 3°C. The IP6 concentration had no obvious influence on the pH deviation, less than 0.5 in whole curing process.When CA concentration was more than 20%, the curing product of IP6/CA double chelating hydroxyapatite cement contained trace amount of calcium citrate tetrahydrate and tricalcium phosphate(TCP) besides HA. The compressive strength of double chelated cement increased with the increasing CA concentration. With 10000-IP6-HA used as the starting powder, the maximum compressive strength of bone cement was up to 54 MPa when 20% CA was used as curing liquid, as well as 57 MPa for 40% CA curing liquid. Along with the increase of IP6 concentration, the heat output and pH variation increased slightly in curing. When CA concentration in curing liquid was above 30%, the temperature rise was more than 4°C and pH variation reached up to 0.7~0.9.The curing product of anti-washout chelating HA bone cement had no change by adding different content of CS, which were HA, calcium citrate tetrahydrate and TCP. The results of quantitative analysis and qualitative observation showed that the anti-washout performance improved with the increase of CS addition. When the content of CS was more than 1%, the cement had good anti-washout ability without collapse in distilled water. The compressive strength followed a parabolic law with the increasing CS addition and reached the maximum,63 MPa, when 2% CS added. Furthermore, the CS addition had no obvious influence on either the heat output(around 3°C) or pH variation(about 0.5).