الفهرس 
PublicationsOnly 14 pages are availabe for public view
 |  | from | 235 |  |  |
| | | from | 235 | | |
Abstract
In this study, new glasses in tellurate and tellurosilicate systems have been synthesized and characterized with an aim to explore their biological activity. Structural properties and biological activity of the resulting glasses were evaluated by mean of both in vitro and in vivo tests. It was concluded that as-prepared tellurate glass, thermal treated silicate and some of mixed former tellerosilicate glasses are promising bioactive materials that can be considered as bioactive implants used for bone repair. Structural techniques have been used to investigate the microstructure of the glasses before and after in vitro test.The effect of thermal heat treatment and mixing two different glass formers on the properties of crystallized biophases including solubility, crystallinity, chemical composition and crystal morphologies have been studied. The correlation between the properties of the biophases and spectral changes of the material tested has been interpreted in terms of bioactivity.Both the type and concentration of the network former (TeO2, or SiO2 or both) was found to have an effective influence on the crystallization of the biophases. The degree of crystallinity of all of the bioactive phases was found to increase with increasing TeO2 content at expense of SiO2 concentration. It is worthy that the morphology form of the crystals well affect the bioactivity. The most appropriate morphology of the apatite crystals is the needle –like that is the most dominant in the studied tellurate and tellerosilicate glasses. This may because needle–like structure morphology may resemble the crystal morphology of tissues of human bone, thus making it much more biocompatible and bioactive. In fact, the properties of apatite, including bioactivity, biocompatibility, and solubility can be tolerated by modifying its structural nature through heat treatment process. In this respect, as-prepared silicate glass was found to consist of amorphous calcium silicate (wollastonite, W) and phosphate phases. Assessments of bioactivity through the in vitro test lend support that the studied bioglasses can be recommended as biomaterials valuable in branches of biomedical applications such as bone repair or bone substitution. This was supported by in vivo tests which carried out on samples implanted in trabecular bone of rabbits. The in vivo results in this work also verify that the implanted bioglass containing apatite of needle like structure have a good bioactivity. The in vivo test of the studied biomaterials ensured their biocompatibility and bioactivity with animal’s tissues, since the osteocytes (bone forming cells) were grew on material – tissues interface. Moreover, the interface of bonding with bone after implantation for 4 weeks is narrow and zigzag-like, showing an intense bonding with bone and rapid ingrowths of bone tissue.