Effects Of Additives On The Injectability And Anti-Washout Property Of ?-Tricalcium Phosphate Cement

?-Tricalcium Phosphate(?-TCP)bone cement is a new type of artificial bone repair material,which has good biocompatibility and osteoinductivity,and can be selfcuring and biodegradable in the human body.In this paper,organic additives of polyvinyl alcohol,chitosan,sodium alginate and corn starch were added to the bone cement.The inorganic additive of hydroxyapatite(HA),a mixture of calcium and phosphorus compounds,and talc powder are compounded with organic additives to the bone cement.The effects of additives on the injectability,compressive strength,curing time,phase composition and fracture morphology of bone cement were studied.In addition,the anti-washout property of injectable calcium phosphate cement was preliminarily explored.The addition of polyvinyl alcohol and chitosan improves the injectability and compressive strength of the bone cement at the same time.The curried cement is composed of a large number of compacted flake-shaped CDHA.The addition of sodium alginate and corn starch increases the size of the flaky CDHA particles in the bone cement and the structure of the cement become porous and loose.When the polyvinyl alcohol content is 3%,the injectability is 66±7%,and the compressive strength is as high as 48.22 MPa.When the chitosan content is 1%,the injectability reaches 76±4%,and the compressive strength is 44.17 MPa.The injectability of the bone cement with0.5% sodium alginate is 62±0.6%,and the compressive strength is 32.91 MPa.The injectability of bone cement with 5% corn starch is 71±1%,and the compressive strength is 36.17 MPa.The HA and calcium phosphate salt are mixed with corn starch respectively,and added into the bone cement.When the HA content is 2%,the compressive strength reaches 40.14 MPa,and the injectability is 69±4%.With the increase of calcium phosphate content to 4%,the injectability gradually increased to 75±2%,but the compressive strength decreased significantly.Talc has a significant effect on the injectability and compressive strength of bone cement.The injectability of 5% talc alone is as high as 85±2%,and the compressive strength is 44.92 MPa.The injectability decreases evidently when the talc was added together with organic agent.Adding talc powder and corn starch to the bone cement together,the compressive strength of the bone cement with 3% talc powder reaches 45.23 MPa,and the injectability is 67±2%.The composite of talc and chitosan is added to the bone cement,and the compressive strength of 1% talc is 40.8MPa,and the injectability is 76±5%.After the pure ?-TCP bone cement was shaken in an aqueous solution for 5 minutes,the slurry broke due to its poor shape retention and could not maintain its complete shape.After adding polyvinyl alcohol,chitosan,and corn starch to the bone cement,the anti-washout property was significantly improved.After shaking for 15 minutes,the slurry can still maintain a complete shape in the aqueous solution.After adding sodium alginate and shaking for 15 minutes,the slurry could not maintain its complete shape,break into many parts,and release a large amount of powder.