الفهرس 
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Abstract
Purpose of the research : Presented work aims to investigate the role of different Strontium oxide concentrations as additive to modified Silicate glass. Materials and methods used: The investigated materials are samples of silicate glass with the main composition 24.5CaO •24.5Na2O •6P2O5 •(45-x) SiO2 •xSrO, mol%, which were prepared by the melt-derived technique. Investigations of the structures and their properties were executed by NMR and XRD techniques. Summary and Conclusions: In this study, glass oxides containing different concentrations of strontium oxide (SrO) were prepared for the purpose of using these materials in medical applications. The effect of substituting strontium oxide with silicon oxide in phosphosilicate glasses modified with sodium and calcium oxides was studied. The structural changes resulting from the addition of strontium oxide were studied based on the results obtained from X-ray spectra, infrared spectra and nuclear magnetic resonance spectra of silicon, phosphorus and sodium nuclei. In addition to studying the effect of chemical composition, the structural composition of these materials was also examined under the influence of heat treatments, which play an effective role in converting ordinary glass to bioceramic glass. The X-ray spectra showed that the strontium oxide-free glass contains randomly distributed compositional groups. On the other hand, the results showed that all samples containing strontium oxide contain synthetic units also distributed randomly in the glass structure, but with the heat treatment of samples containing different concentrations of strontium oxide, The results showed that all samples containing strontium oxide after heat treatment at crystallization temperature (Tc) contain structural units arranged in a regular manner in the glass structure. The phases of these synthetic units were determined, which were classified as polycrystalline units. The most important crystalline phases, which are identical to the biological phases in the bones of the organism, and which play the main role in making these materials important for application in the medical field, were identified, as it could be used as a major part in the preparation of glass cement, from this, it was possible to determine the effective role of strontium oxide, which was confirmed to play an important role in increasing the hardness of the glass to specifically face the overloading of the studied materials. For example, the resonance of phosphorous cores (31P NMR) and the results of Hardness Measurements for different concentrations of strontium oxide and the rest of the other results, it was found that it improves the hardness of the main materials constituting teeth and bon. It was found that strontium oxide plays a major role as a preserver of the crystallization process and the glass transformation process from glass to ceramic and glass ionomer cement, which has an effective role because it contains active substances similar to the phases that form bones and teeth .The biological phases that contain biological phases (Apatite and Wollastonite) were confirmed, in addition to the important phase resulting from adding strontium oxide with heat treatment at crystallization temperature (Tc), which improved the hardness of glass cement and glass ceramic, which is (Calcium Strontium Phosphate- CaSr2(PO4)2).