The Effect of Bioactive Glass Synthesis Method on the Flowability and Structural Stability of the Injectable Pastes Prepared from It

The present project primarily aims to investigate the effect of synthesis method of the bioactive glass powder on the flowability and structural stability of the pastes from it. In this study, 45S5 bioactive glass was synthesized by melting and sol-gel methods. The rheological properties, injectability, washout resistance, and behavior of calcium phosphate deposition formation in the simulated body solution after 21 days were investigated using UV-visible spectroscopy, inductively coupled plasma atomic emission spectroscopy, and scanning electron microscopy. Finally, the cytotoxicity test was carried out, and its dependence on the concentration of the ions released from different pastes was evaluated. The bioactive glass powder prepared through the melting method was non-porous with a specific surface area of about 3 m2g-1 while the powder prepared by the sol-gel method was porous with a specific surface area of about 12 m2g-1. The values of the yield stress, viscosity, and thixotropy in the paste prepared by the sol-gel glass were higher than those of the sample prepared by melting method, and the injection force increased by about five times. Use of sol-gel glass led to the formation of pastes with lower washing resistance and for this reason, the dissolution and release rate of the ions from the paste containing sol-gel glass was higher than those of the same sample with molten glass. Increasing the specific surface area of the powder led to faster formation of the apatite layer on the surface of the samples; however, the rate of cell proliferation decreased due to the high concentration of ions in the environment.