Reinforcement of a wollastonite cement (CaSiO3) by carbon nanotubes for biomedical or dental applications

Abstract

In the last decades, the life expectancy of the population has been increasing and with it some age-related evils such as Osteoporosis and Osteoarthritis. In orthopedic surgeries, for example, there may be a need to fill defects with materials compatible with the patient's bone system. Thus, there is a need to develop materials to repair and interact with biological systems, also known with biomaterials. Calcium silicate-based bioceramics, such as wollastonite (CaSiO3), have great potential because of their similarity to the bone structure of the human body, low toxicity, bioactivity, and biocompatibility. The main feature, however, is the formation of a layer of hydroxyapatite on its surface. Thus, the use of wollastonite to make cements for the dental and orthopedic application is quite feasible and has great potential, since it presents biocompatibility similar to that of the bioglass and superior to the phosphate based cements. Several methods can be used to produce wollastonite, such as precipitation and reaction in the solid state. The sol-gel method presents an advantage in relation to the others to produce silicates with high homogeneity. This characteristic is indispensable for biological applications.However, the low mechanical resistance to fracture is often a limitation for the use of wollastonite in different applications. An interesting approach is to reinforce the cement with carbon nanotubes. Thus, in addition to biocompatibility, this cement would have mechanical resistance comparable to phosphate based cements. Previous studies on polymer matrices and on certain bioceramics have already proved the efficiency of nanotubes in increasing the final mechanical properties of these materials. Although recent studies have shown this potential, few studies have dealt with nanotube reinforced wollastonite, and still less has a comprehensive study on the characterization of the mechanical properties of these reinforced cements. In this way, this work would present an unpublished study for the formation of a wollastonite based cement that would have a good biocompatibility while presenting adequate mechanical properties. The main objective of this work is to incorporate the functionalized carbon nanotubes in a wollastonite based cement, in order to modify the final mechanical properties of this cement, without losing the biocompatibility. In addition, it is intended to make a more extensive study regarding the characterization of the mechanical properties of these cements reinforced with carbon nanotubes. Therfore, a wollastonite with better mechanical properties can be applied in dental and orthopedic procedures more comprehensively, reducing the risk of fracture. In addition, the study of wollastonite (CaSiO3) may help to better understand the kinetic and chemical mechanisms of other calcium silicates. (AU)