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The core aim of this study was to investigate zinc (Zn)and zinc and strontium (ZnSr)-containing brushite-forming β-tricalcium phosphate (TCP) cements for their effects on proliferation and differentiation of osteoblastic-like cells (MC3T3-E1 cell line) as well as for their in vivo behaviour in trabecular bone cylindrical defects in a pilot study. In vitro proliferation and maturation responses of MC3T3-E1 osteoblastic-like cells to bone cements were studied at the cellular and molecular levels. The Zn-and Sr-containing brushite cements were found to stimulate pre-osteoblastic proliferation and osteoblastic maturation. Indeed, MC3T3-E1 cells exposed to the powdered cements had increased proliferative rates and higher adhesiveness capacity, in comparison to control cells. Furthermore, they exhibited higher alkaline phosphatase (ALP) activity and increased Type-I collagen secretion and fibre deposition into the extracellular matrix. Proliferative and collagen deposition properties were more evident for cells grown in cements doped with Sr. The in vivo osteoconductive properties of the ZnCPC and ZnSrCPC cements were also pursued. Histological and histomorphometric analyses were performed at 1 and 2 months after implantation, using carbonated apatite cement (Norian SRS ® ) as control. There was no evidence of cement-induced adverse foreign body reactions, and furthermore ZnCPC and ZnSrCPC cements revealed better in vivo performance in comparison to the control apatite cement. Additionally, the presence of both zinc and strontium resulted in the highest rate of new bone formation. These novel results indicate that the investigated ZnCPC and ZnSrCPC cements are both biocompatible and osteoconductive, being good candidate materials to use as bone substitutes. a Both authors contributed equally to this work 163 www.ecmjournal.org S Pina et al. Brushite-forming bone cements

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This paper reports on the synthesis of magnesium aluminate spinel (MAS) powders and consolidation of MAS ceramics by hydrolysis-induced aqueous gelcasting (GCHAS). The MAS powders surface passivated against hydrolysis were dispersed in an aqueous-organic premix solution using suitable dispersants. The consolidation of green bodies occurred under ambient conditions by adding a polymerization initiator, a catalyst, and AlN (0-4.06 wt%) as a cosetting agent. Green samples with exceptionally high green strength (B21 MPa) were obtained in the presence of 4.06 wt% AlN. Sintered (16501C, 1 h) MAS ceramics consolidated by GCHAS exhibited mechanical properties that are comparable to those consolidated by dry pressing.