Effect of silane treatment and different resin compositions on biological properties of bioactive bone cement containing apatite-wollastonite glass ceramic powder

In methylmethacrylate (MMA)-based cements containing bioactive particles, polymethylmetacrylate (PMMA) is known to suppress the bioactivity of Bioglass(R) and apatite-wollastonite glass ceramic (AW-GC). Little is known about the effect of different silane treatment methods on the bioactivity of AW-GC. MMA-based cement plates containing dry silanated AW-GC particles and PMMA particles of different molecular weights (12,000-900,000) were immersed in simulated body fluid (SBF). Cements containing PMMA particles of high molecular weight formed an apatite layer on the surface after 24 h. Using PMMA particles with a molecular weight of 60,000 and AW-GC particles silanated with different methods (dry method vs. slurry method), cement plates were made and immersed in SBF. Only cement plates containing dry silanated AW-GC particles showed apatite formation in SBF after 3 days. In vivo implantation in rat tibias of MMA-based cement containing dry silanated AW-GC particles and PMMA particles (molecular weight 900,000) demonstrated an affinity index of 32.1 +/- 15.8% after 8 weeks of implantation compared to 89.4 +/- 10.7% achieved by bisphenol-A-glycidyl methacrylate based cement containing the same bioactive powder. By using a dry method of silane treatment and high molecular weight PMMA particles, the bioactivity of cement based on MMA monomer was achieved; but further effort is needed to improve the mechanical properties of the composite.