Novel hardystonite calcium phosphate mixture as a potential cementitious bone filling material

Abstract

In this work, we have described the fabrication and characterization of novel cement containing hardystonite (HT; Ca2ZnSi2O7) as a bioactive phase which was mixed with brushite (B; CaHPO4. 2H2O) calcium phosphate and citrate liquid as setting solution. Effect of various citrate concentration in hardening solutions consisting of the mixture of citric acid and trisodium citrate dihydrate were used to study the phase transformations, mechanical properties, microstructural changes and in vitro cytotoxicity of cements. The results showed that while the HT phase revelead slow hydration ability, the brushite was gradualy hydrolyzed with increasing concentration of citrates in liquid. The mechanical strength increased in wet and dry state as the concentration of the citrates increased, with the highest values observed in the citrate_8 % cement. The in vitro cytotoxicity testing of cement extracts revealed high viabilities of osteoblasts in citrate_1 % and citrate_4 % but a moderate extract cytotoxicity was verified in citrate_8 % cement.