In vivo Bioactivity of a Mineral Based Orthopaedic Biocement

Due to the shortcomings of the PMMA and calcium phosphate cements in many orthopedic applications there is a constant development of new cement formulations. This article describes an injectable chemically bonded ceramic based on the Mayernite-Marokite-Grossite mineral system. This article focuses on the chemical interactions between material and bone tissue. The interface between bone and the bioceramic material was studied using electron microscopy after 6 weeks of implantation in a model involving injection of the non-cured paste into drilled cavities in the tibia condyle of rabbits. After termination the implants were fixated, cut and embedded in resin. The embedded implants were polished and subsequently studied by electron microscopy. To give a general overview of the interface, SEM combined with EDS was used. More in-depth studies were done using TEM combined with EDS and electron diffraction. To prepare the TEM samples, focused ion beam (FIB) technique was used, facilitating a very precise control of the sample site. As reference, PMMA cement was also studied. The studies reveal the biocement to be bioactive, i.e. to form chemical and biological bonding between the biocement and bone tissue. No sharp interface could be found even at very high magnification in TEM indicating cellular interaction. techniques and the areas of research have also been emphasized.