Résumé
Objective:To explore the effect of decalcified bone matrix (DBM) rich in biological activity on surgical-grade medical calcium sulfate, and to observe the change of different content of DBM on the physical and chemical properties of calcium sulfate, which provide theoretical basis for the preparation of calcium sulfate bone cement with osteogenic and injectable properties.Methods:DBM with weight content of 0, 5%, 10%, 20%, 30%, 40% was fully mixed with CSH. Dissolve 0.3 g of methyl cellulose in 10 ml of deionized water to prepare a 3% methyl cellulose solution. Methylcellulose solution was added according to the liquid-solid ratio of 0.4. The mixture was evenly stirred to form slurry, then the degradation rate, compressive strength, setting time and and pH value of calcium sulfate in vitrowas measured.Results:The initial setting time and final setting time of calcium sulfate were 4.96±0.20 and 5.83±0.12 min respectively. With the increase of DBM content, the initial setting time and final setting time increased significantly ( F=49.275, P<0.05; F=124.859, P<0.05). The compressive strength of pure calcium sulfate is 23.33±6.35 MPa; when the content is 40%, the compressive strength is only 3.33 MPa. With the increase of DBM content, the compressive strength first increased and then decreased; the content of 5%, 10%, 20% DBM had little effect on the compressive strength ( P>0.05), while the compressive strength of 30% and 40% groups decreased significantly ( t=3.259, P<0.05). DBM with different contents can significantly change the degradation rate of calcium sulfate complex. When the content of DBM is 30% and 40%, the complete degradation time in vivo is only 10 d, while the degradation rate of calcium sulfate is 63% in 30 d. At any time point in vitro degradation, DBM had no significant effect on the pH value of calcium sulfate complex culture medium, and the change law was consistent with that of pure calcium sulfate. Conclusion:With the increase of DBM content, the degradation rate is gradually accelerated, the compressive strength is reduced, and the setting time is prolonged, which is not conducive to the preparation of injectable calcium sulfate cement.