EVALUATION OF CALCIUM ALUMINATE CEMENT BASED COMPOSITIONS FOR BONE REPAIR VIA EX VIVO TESTS.

Reference	Presenter	Authors (Institution)	Abstract
02-008	Julia Marinzeck de Alcântara Abdala	Abdala, J.M.(Universidade do Vale do Paraíba); Vasconcellos, L.M.(Universidade Estadual Paulista); Pandolfelli, V.C.(Universidade Federal de São Carlos); Oliveira, I.R.(Universidade do Vale do Paraíba);	The need to treat osseous defects is increasing dramatically as the population grows old. Some studies have reported calcium aluminate cement (CAC) applications for repairing bone defects, based on the fact that its chemical composition and thermal expansion coefficient are similar to human bones. CAC has also the potential to be used in orthopedics, as it can avoid some problems of commercial products (PMMA, polymethyl methacrylate) regarding its handling behavior (too low consistency and strong odor) and exothermic reactions (local heat increase which can damage the surrounding tissue). Besides that, CAC can be molded in situ to provide intimate fitting to the defect rims. In this work, compositions based on CAC containing 4 wt% of additives (alumina, zirconia, hydroxyapatite or tricalcium phosphate) or 1 wt% of (chitosan) were evaluated. The injectability of cements is an important issue when minimally invasive surgical techniques are used and for applications with limited accessibility and narrow cavities. The compositions were prepared with different solid content and evaluated by manual injectability using capillary tips (diameter 1.1 mm) or hypodermic (diameter 1.6 mm) needles. The best injectability conditions were used for the ex vivo tests. In the latter, the compositions and PMMA were injected to repair 3 mm defects of mouse femurs cut into pieces of 10 mm. After setting of materials for 24 h at 37oC in body fluid solution (SBF) the pieces were submitted to uniaxial cold crushing strength tests. The pieces filled with chitosan and plain CAC showed the highest compressive strength compared to other compositions. Besides that, injectable pastes based in CAC were developed with mechanical properties comparable to PMMA.
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