Development of β‐tricalcium phosphate/sol‐gel derived bioactive glass composites: Physical, mechanical, and in vitro biological evaluations

In this study, composites of β‐tricalcium phosphate (β‐TCP) and sol gel derived bioactive glass (10, 25, and 40 wt %) based on the SiO 2 ‐CaO‐MgO‐P 2 O 5 system were prepared and sintered at 1000–1200°C. The mechanical properties were investigated by measuring bending strength, Vickers hardness and fracture toughness. Structural properties were evaluated by XRD and SEM analysis, and the biological properties were studied by soaking the samples in simulated body fluid (SBF) and in contact with osteoblastic cell for viability assay. When the samples were sintered at 1200°C, the mechanical strength increased, up to 34%, by increasing the amount of bioactive glass phase. In contrast, it decreased when the samples were sintered at 1000 and 1100°C. The results showed that the strength could be improved up to 56% when more firing period was used. Incorporation of the bioactive glass phase into β‐TCP increased the microhardness but did not significantly change the fracture toughness. Phase analysis revealed that β‐TCP or magnesium‐substituted β‐TCP was the main crystalline phase of the composites beside some calcium silicate crystallized in the bioactive glass phase. Plenty precipitation of calcium phosphate layer onto the surfaces of the β‐TCP/bioactive glass composites soaked in SBF indicated superior bioactivity of these materials compared to pure β‐TCP without any precipitation. The ability of β‐TCP/bioactive glass composites to support the growth of human osteoblastic cells was considerably better than that of pure β‐TCP. These results may be used to indicate which compositions and processing conditions can provide appropriate materials for hard tissue regeneration. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009