چكيده به لاتين
Calcium phosphate cement, as common injectable bone cement, has been considered as a candidate in minimally invasive surgical methods. Nevertheless, some drawbacks such as non-degradability in apatite type and severe variation in pH and temperature during the setting process in brushite type limited its application. As an alternative, magnesium phosphate cement, that can cover the drawbacks, has been evaluated by researchers. In this research, adding calcium, carboxylated single carbon nanotube and gelatin to magnesium phosphate cement was assessed to more control cementation and also enhance mechanical and biological properties. First, Mg21Ca4Na4(PO4)18 powders, as cement precursor powders, were produced by emulsion precipitation method and calcined at 950 C. The dissolution rate of the precursor powders compared to Mg3(PO4)2, produced with the same conditions, were decreased due to adding calcium. Hence, the event enabled applying a higher amount of powder to liquid ratio about 2 g/ml and reaching to 21 MPa compressive strength. Adding carbon nanotube, due to its twofold role, delaying at the first and accelerating at the later, did not make a significant variation in setting time, however, decrease the cement paste viscosity at first. The compressive strength of the cement was improved to 28 MPa because of the role of carbon nanotubes as a preferred site for precipitation in the liquid part of the paste. Although setting time and compressive strength of the cement were decreased by adding gelatin, proliferation and differentiation of mouse bone marrow mesenchymal stem cells were improved. In other words, the composite cement compared to simple magnesium phosphate cement obtained higher compressive strength and indicated osteoinductivity in addition to osteoconduction ability.
