Analysis of mechanical and biological properties of fast setting time nanostructured biphasic calcium phosphate bone cement

ABSTRACT

Over the past two decades, the development of new therapies for applications in degenerative bone tissue diseases has intensified, as well as less invasive forms of road accident trauma treatment. In this scenario, fast setting time calcium phosphate bone cement (CFCs) for injectable and/or moldable applications allows for use through minimally invasive surgical techniques. CFC arrays have attracted great interest for use in orthopedics and dentistry as substitutes for damaged parts of the osteochondral system, allowing their use in bone repair or filling. In this work, CFCs consisting of two different biphasic calcium phosphates (BCP) were processed, one with micrometric distribution and the other with nanometric distribution, sodium phosphate and carboxymethylcellulose, aiming at the use of this material in surgical procedures. The raw materials were physically and chemically characterized by X-ray diffraction, scanning electron microscopy coupled with X-ray dispersive energy spectroscopy. The setting time of the material was evaluated by Vicat tests and the mechanical strength of the CFC was evaluated through the flexural tests (tensile strength), ultramicrohardness (modulus of elasticity). Biological properties were evaluated by in vitro Tris-HCL degradation assay, cytotoxicity assay by bacterial culture and in vivo assay by the HET-CAM method. The results showed a better performance of the nanometer CFC, having a low final setting time, 22 minutes, and mechanical strength of 4 MPa, compatible with the expected expectation for cancellous bone. Biological assays confirmed the satisfactory biological response of these nanocomposites. This demonstrates that the material has potential for clinical application in place of the widely used acrylic cement.

Keywords
Bone cement; Biphasic calcium phosphate; Setting time; Mechanical strength