Evaluation of the influence of bone cement based on calcium silicate, modified with different cations, on bone repair

Abstract

Currently there are two materials commonly used for bone repair, TCP (tricalcium phosphate) and bioglass. Although the bioglass has biological properties superior to the TCP, it is not possible to make a cement only with bioglass, so 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 the bioglass, being the wollastonite cement precursor due to its superior biocompatibility to that of the phosphate-based cements and its high reactivity with the activating solution. Based on this assumption, the objective in this project will be to evaluate the impact of different activating solutions on the ± and ² wollastonite phases for the formation of calcium silicate cement. Samples will be produced with different activating solutions, this activating solution is a buffer solution (pHH7) composed of phosphate and cations, and its composition can be varied. The change in composition allows to change the final composition of the cement and control its mechanical and biological characteristics. Subsequently, the different materials obtained, made of calcium silicate, will be analyzed by in vivo study on 12 Wistars rats that will be submitted to creation of a critical defect with 3,0mm measurement in the tibia and will randomly receive padding with three experimental materials, besides the control group (clot). After 4 weeks, all animals will be euthanized. The tibias will be conditioned in 10% formalin and submitted to histological and histomorphometric analysis for visualization and quantification of bone neoformation in the critical defects. The data will be statistically analyzed, initially by means of the normality test aiming the application of the appropriate statistical test. The level of significance adopted will be the conventional value of 5%.