Abstract
Aims: to investigate the role of gelatin on the setting properties of α-tricalcium phosphate based cement.
Methods: gelatin α-TCP powders were prepared by grinding and sieving the solid compounds obtained by casting gelatin aqueous solutions containing a-TCP. 5% wt of CaHPO42H2O were added to the cement powders before mixing with the liquid phase, with a L/P ratio of 0.3 mL/g. Teflon moulds were used to prepare cement cylinders 6 mm in diameter and 12 mm high. X-ray diffraction analysis, mechanical tests, SEM, dsc and TG investigations were carried out on the cements after different times of soaking in SBF.
Results: The setting reaction of the control cement is completed in 7 days, whereas the transformation into apatite of the cements at high gelatin content occurs in just 2 days of aging in SBF. The fractured surface of the aged control cement is covered with entangled plate like apatite crystals, whereas gelatin cements display much more compact surfaces, most likely because of the inhibiting effect of gelatin on apatite crystal growth. The microstructural modifications are in agreement with the reduction of the total porosity, and with the improvement of the mechanical properties of the aged cements, on increasing gelatin content. The compressive strength of the cements increases linearly with the increase of gelatin. The results of the thermogravimetric analysis indicate a strong interaction between gelatin and hydroxyapatite crystals.
Conclusions: the results of this paper indicate that gelatin can be successfully used to improve and modulate the mechanical properties of α-TCP-based cements.
The abstracts were prepared by Ms Grazia Gliozzi. Correspondence should be addressed to her at the Italian Orthopaedic Research Society, Laboratory for Pathophysiology, Instituti Ortopedici Rizzoli, University of Bologna, Bologna, Italy.
