In vitro bioactivity of a glass-ceramic biomaterialwith near-eutectic composition of thepseudo-binary system diopside–tricalciumphosphate


Claudia Magdalena López-Badillo

The in vitro bioactivity of slightly hypereutectic glass-ceramics of the pseudo-binary sys-tem diopside (CMS2, CaMgSi2O6)–tricalcium phosphate [Ca3P, Ca3(PO4)2], was tested in aSimulated Body Fluid (SBF) from 7 to 21 days at pH = 7.3 and 36.5◦C. The materials were syn-thesized by the petrurgic method, using cooling rates of 0.5, 1 and 2◦C/h through the mushyzone. Their microstructure consisted of -C3Pss (solid solution of CMS2in Ca3P) primarydendrites in a matrix of CMS2–-C3Pss lamellar eutectic phase. The dissolution of the inter-dendritic matrix into the SBF lead to the formation of an interconnected porous structureat the surface of the samples. Subsequently, the -C3Pss primary dendrites were pseu-domorphically converted into (Ca10−yMgy)(PO4)6−z(SiO4)z(OH)2−z(Mg and Si co-substitutedhydroxyapatite, HAp). The cavities left by the dissolved matrix were then filled with HAp,and a layer of this phase was formed on the surface of the material. The rate of dissolutionof the material’s matrix into the SBF, the rate of precipitation of HAp from the solution, thecomposition of the precipitated HAp, and pH and ionic composition of the SBF during thetests, were all affected by the cooling rate used to synthesize the materials.

Artículo-CMLB 1 2020