This work reports on the effect of the amount (0, 10, and 30 wt %) and type of HA powder incorporated into an acrylic bone cement on the tensile properties, compression properties, and fracture toughness. The three different types of HA powders used were synthesized in the laboratory and coated with a silane agent prior to incorporation into the cement powder, and differed in particle size, water content, surface area, and crystallinity. It was found that the inclusion of any type of HA powder led to an increase in the tensile modulus (ET), but all the other mechanical properties of the cement decreased (relative to the values of the unfilled cement). The increase in ET is attributed to the good adhesion between the filler and the cement matrix, which is due to the silane coating agent. The decrease in the other mechanical properties may be a consequence of HA powder agglomeration and porosity. Hydroxyapatite morphology and crack-growth mechanisms were analyzed by scanning electronic microscopy (SEM).

The effect of type and amount of hydroxyapatite on the setting kinetics of an experimental bone cement based on poly(methyl methacrylate-co-styrene) was studied. The average molecular weights of the polymeric beads synthesized were determined by SEC and the average particle size was determined by Optical Microscopy. Three types of hydroxyapatites were synthesized in the laboratory and then characterized by ICP, FTIR and X-ray diffraction. To obtain more compatible fillers, the hydroxyapatites were treated with 3-trimethoxysilylpropylmethacrylate. Bone cements formulations filled with 0, 10, 30, and 50 weight % of hydroxyapatite powders were prepared and the kinetics of setting was followed by Differential Scanning Calorimetry. The presence of hydroxyapatite decreased the reaction rate and increased the degree of conversion, which could be beneficial for the long time stability of the implant.

Ceramic materials mimic the mineral composition of native bone and feature osteoconductive properties; they are therefore used to regenerate bone tissue. Much research focuses on increasing the porosity and pore interconnectivity of ceramic scaffolds to increase osteoconductivity, cell migration and cell-cell interaction. We aimed to fabricate biocompatible 3D-scaffolds featuring macro- and microporous calcium phosphates with high pore interconnection. Nanoparticles of hydroxyapatite (HA) and calcium deficient hydroxyapatite (CDHA) were synthesized by wet chemical precipitation. Scaffolds were produced from them by the replication polymeric foam technique. Solid content and sintering temperature were varied. Nanoparticles and scaffolds were characterized regarding morphology, chemical and mineral composition, porosity and mechanical properties. Biocompatibility, cell attachment and distribution were evaluated in vitro with human adipose mesenchymal stem cells. Scaffolds with total porosity of 71%–87%, pores in the range of 280–550 µm and connectivity density up to 43 mm−3 were obtained. Smaller pore sizes were obtained at higher sintering temperature. High solid content resulted in a decrease of total porosity but increased interconnectivity. Scaffolds 50HA/50β-TCP featured superior interconnectivity and mechanical properties. They were bioactive and biocompatible. High HA solid content (40 wt.%) in the HA pure scaffolds was negative for cell viability and proliferation, while in the 50HA/50β-TCP composite scaffolds it resulted more biocompatible.

Biocompatibility, injectability and in situ self-setting are characteristics of calcium phosphate cements which make them promising materials for a wide range of clinical applications in traumatology and maxillo-facial surgery. One of the main disadvantages is their relatively low strength which restricts their use to nonload-bearing applications. α-Tricalcium phosphate (α-C3P) cement sets into calcium-deficient hydroxyapatite (CDHA), which is biocompatible and plays an essential role in the formation, growth and maintenance of tissue-biomaterial interface. β-Dicalcium silicate (β-C2S) and tricalcium aluminate (C3A) are Portland cement components, these compounds react with water to form hydrated phases that enhance mechanical strength of the end products. In this study, setting time, compressive strength (CS) and in vitro bioactivity and biocompatibility were evaluated to determine the influence of addition of β-C2S and C3A to α-C3P-based cement. X-ray diffraction and scanning electron microscopy were used to investigate phase composition and morphological changes in cement samples. Addition of C3A resulted in cements having suitable setting times, but low CS, only partial conversion into CDHA and cytotoxicity. However, addition of β-C2S delayed the setting times but promoted total conversion into CDHA by soaking in simulated body fluid and strengthened the set cement over the limit strength of cancellous bone. The best properties were obtained for cement added with 10 wt % of β-C2S, which showed in vitro bioactivity and cytocompatibility, making it a suitable candidate as bone substitute.

Bioactive glasses (BGs) are attractive materials for bone tissue engineering because of their bioactivity and osteoinductivity. In this study, we report the synthesis of a novel phosphorous pentoxide-free, silicate-based bioactive...