Avaliação do comportamento biológico e das modificações composicionais de vitrocerâmicas à base de wollastonita e de fosfato tricálcico para regeneração óssea

Abstract

Introduction: Wollastonite (W) and tricalcium phosphate (TCP) minerals have recognized biocompatibility and different behaviors in biological fluids. Glass-ceramics were developed in the form of granules, with different W and TCP weight percentages in order to obtain different solubility, bioactivity and biodegradability behaviors during bone repair in a critical bone defect. Objective: To evaluate vibrational and structural properties, as well as in vivo biological behavior and compositional modifications of glass-ceramics in the form of granules with different W and TCP weight percentages . Materials and methods: 76 male Wistar rats were used, which were divided into four experimental groups according to each glass-ceramic type - W20/TCP80, W40/TCP60, W60/TCP40 and W80/TCP20 -, plus a positive control group and a negative control group with untreated bone defect. Samples were macroscopically evaluated and by digital radiography over seven days after implantation, and by Raman spectroscopy at the following biological points: 07, 15, 45 and 120 days. Results: Before implantation, Raman spectroscopy identified different predominance of α-W, β-TCP and α-TCP polymorphs in glass-ceramics. W40/TCP60, W60/TCP40 and W80/TCP20 showed better agglutination after hydration. In all biological points, no signs of rejection were observed. Along seven days, tissue formation was macroscopically observed, involving implanted granules in all study groups. Over the analyzed periods, Raman bands showed formation of components associated with organic matrix and presence of inorganic components, with greater spectral similarity of bone tissue to the W60/TCP40 glass-ceramic. Conclusion: Glass-ceramicsshowed in vivo tolerance, and W60/TCP40 and W80/TCP20 showed gradual compositional changes, which indicate adequate performance for application as bone substitute, with better evidence for the W60/TCP40 glass-ceramic. W20/TCP80 glass-ceramic did not show noticeable in vivo compositional changes, showing potential for using as filling material.