The role of Sr2+ on the structure and reactivity of SrO–CaO–ZnO–SiO2 ionomer glasses

• Published in: Journal of materials science. Materials in medicine Vol. 19; no. 2; pp. 953 - 957
• Main Authors: Boyd, Daniel, Towler, Mark R., Watts, Sally, Hill, Robert G., Wren, Anthony W., Clarkin, Owen M.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.02.2008; Springer Nature B.V
• Subjects: Biochemistry; Biocompatible Materials; Biomaterials; Biomedical Engineering and Bioengineering; Biomedical materials; Calcium Compounds - chemistry; Cement; Ceramics; Chemistry and Materials Science; Composites; Dental Cements; Glass; Glass - chemistry; Magnetic Resonance Spectroscopy; Materials Science; Natural Materials; Oxides - chemistry; Polymer Sciences; Regenerative Medicine/Tissue Engineering; Silicon Dioxide - chemistry; Strontium - chemistry; Studies; Surfaces and Interfaces; Thin Films; X-Ray Diffraction; Zinc Oxide - chemistry; Polyacrylic Acid; Glass Network; Glass Powder; Strontium Ranelate; Glass Structure
• ISSN: 0957-4530; 1573-4838
• DOI: 10.1007/s10856-006-0060-7

The suitability of Glass Polyalkenoate Cements (GPCs) for use in orthopaedics is retarded by the presence in the glass phase of aluminium, a neurotoxin. Unfortunately, the aluminium ion plays an integral role in the setting process of GPCs and its absence is likely to hinder cement formation. However, the authors have previously shown that aluminium free GPCs may be formulated based on calcium zinc silicate glasses and these novel materials exhibit significant potential as hard tissue biomaterials. To further improve their potential, and given that Strontium (Sr) based drugs have had success in the treatment of osteoporosis, the authors have substituted Calcium (Ca) with Sr in the glass phase of a series of aluminium free GPCs. However to date little data exists on the effect SrO has on the structure and reactivity of SrO–CaO–ZnO–SiO 2 glasses. The objective of this work was to characterise the effect of the Ca/Sr substitution on the structure of such glasses, and evaluate the subsequent reactivity of these glasses with an aqueous solution of Polyacrylic acid (PAA). To this end 29 Si MAS-NMR, differential scanning calorimetry (DSC), X-ray diffraction, and network connectivity calculations, were used to characterize the structure of four strontium calcium zinc silicate glasses. Following glass characterization, GPCs were produced from each glass using a 40 wt% solution of PAA (powder:liquid = 2:1.5). The working times and setting times of the GPCs were recorded as per International standard ISO9917. The results acquired as part of this research indicate that the substitution of Ca for Sr in the glasses examined did not appear to significantly affect the structure of the glasses investigated. However it was noted that increasing the amount of Ca substituted for Sr did result in a concomitant increase in setting times, a feature that may be attributable to the higher basicity of SrO over CaO.