UK India Education and Research Initiative

Biocompatibility of Ionomer Glasses and Glass Ceramics

Summary

Indo-UK project entitled “Effect of cation substitution on the structure and biocompatibility of ionomer glasses and glass ceramics”, was funded by UK-India Educational Research Initiative (UKIERI) in January, 2009 for the period of three years with Dr. Bikramjit Basu as Indian Key Leader (Principal Investigator) and Dr. Artemis Stamboulis as UK Principal Investigator. Osteoporosis is one of the most common health risk faced by vast majority of the ageing population across the globe, especially by post-menopausal women. The occurrence of this systemic skeletal disease will eventually make the bone weak, porous and fragile. The survival of implants in such patients is very low, as osteoporosis affects the process of osseointegration and such patients otherwise have to undergo revision surgery. Considering the growing need to develop bone substitute materials that can improve bone formation as well as reduce bone resorption, a joint venture was initiated between Dr. Bikramjit Basu (Indian principal investigator) and Dr. Artemis Stomboulis (UK principal investigator) to fabricate ionomer substituted glass- ceramic based implant to enhance faster bone healing. One of the most groundbreaking research outcomes of this UKIERI collaboration was the study on the in vivo biocompatibility and osseointegration of strontium containing glass ceramic implants in rabbit model, which was later published in the most prestigious journal, Biomaterials. The uniqueness of this work was the comprehensive integration of Materials Science and Biological Scienceconcepts towards the development of novel glass ceramic implants for hard tissue replacement. In vivo short term implantation experiments were carried out with Strontium-substituted glass ceramics with a nominal composition of 4.5SiO2-3Al2O3- 1.5P2O5-3SrO-2SrF2 of up to 12 weeks in rabbit animal model. The neobone formation at the interface of Sr- containing biomaterials was qualitatively and quantitatively assessed over various time points using micro- computed tomography, fluorescence microscopy and histomorphometric analysis. Such a detailed and systematic study established the short term implant stability of Sr-substituted glass ceramics, enabling dynamic healing along with bony reconstruction in rabbit, as confirmed by the polychrome sequence labeling of fluorochromes. Overall, the results suggested implant stability, homogeneous bone formation around the test implants as well as excellent osteoconductive property comparable to that of a commercially available bioactive implant, i.e. HA-based bioglass. In summary, the recenbtly concluded UKIERI project led to the creation and evaluation of novel glass ceramic implants that was found to be biocompatible in vivo, with regard to the local effects after implantation.