Characterisation of modified glass-ionomer cements for medical applications

Medical-grade glass ionomer cements (GICs) are commercially available for surgical implantation in otology. GICs have advantageous properties as a bone replacement material, including the ability to bond to mineralised tissue such as bone and a good biocompatibility in vivo. However, cement compositions are largely based on the GIC dental cement compositions they were derived from and are not optimised for use in medical applications. The specific objective of this project was to produce improved GICs for surgical application in otology, based upon a commercially available bone cement and tailor the properties to the specific needs of the surgeon while preserving the beneficial properties of the original composition.

Novel GICs based on the substitution of calcium with either strontium, barium or a mixture of species in the ionomer glass component were fabricated and characterisation of the glass and cements undertaken in addition to NMR (nuclear magnetic resonance) analysis of the effect of additives in GICs setting reactions.

The substitution of strontium and barium ions produced cements with improved properties that compared favourably with the commercial material (SerenoCem®) used as a control in this study. Radiopacity and biocompatibility were enhanced without a significant negative effect on the cement properties. XRD (X-Ray Diffraction) of the heat-treated glasses identified Sr/Ba analogous phases present to those reported previously in the literature.

It was concluded that modified ionomer glasses based on the SerenoCem® medical cement composition, tailored for improved properties, will allow the material to accommodate the specific needs of the surgeon and therefore increase clinical viability in bone replacement surgery.