There are currently two materials commonly used for bone repair, TCP (tricalcium phosphate) and bioglass. Although bioglass has biological properties superior to TCP, it is not possible to make a cement using only bioglass, therefore TCP is still the most used material for this purpose. An alternative to TCP is calcium silicate cement (CaSiO3), since it manages to combine the ability of TCP to form cement with the bioactivity of bioglass, wollastonite being the precursor of cement due to its biocompatibility, which is superior to that of base cements. Phosphate and its high reactivity with the activator solution. In order to improve properties, different reinforcement methods have been studied and there is a great emphasis on the use of carbon nanotubes (CNT), due to their excellent mechanical, thermal, structural and electrical properties. Based on this assumption, the objective of this study will be to evaluate the cytotoxicity and the biological properties of bone cement based on calcium silicate incorporated with CNT, in bone regeneration in critical defects in rat tibias. Samples will be produced using CaSiO3 cement with the buffer activating solution (pHH7) composed of ammonia and cations. Initially, the groups a) SiCa; b) SiCa + 0.2% CNT; c) SiCa + 0.5% CNT will be evaluated for cytotoxicity after 3 and 10 days using the MTT test. Twenty-four adult male rats will be used in this study. Initially, 3 mm diameter perforations will be made in the right and left tibia using serial drills and abundant irrigation. The animals will be divided into 3 groups according to the filling of the bone defect: a) SiCa; b) SiCa + 0.2% CNT; c) SiCa + 0.5% CNT, and the clot group will be the control group. Both critical defects will be filled with the same material, and after 3 weeks of surgery the animals will be euthanized. The right tibia will be submitted to a three-point flexion test and the left tibia will be histologically and histomorphometrically analyzed to check the resistance and the best way of developing bone regeneration from the influence of the biomaterial. The data will be statistically analyzed, initially through the normality test in order to apply the appropriate statistical test. The level of significance adopted will be the conventional value of 5%.
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