Pore characterisation and interconnectivity studies on bioactive 58 S sol-gel glass

The interconnecting pore network of bioactive 58S sol-gel glass is a vital structural characteristic requiring investigation, as in vivo this will provide the route of tissue fluid ingress and ultimately, the sites for early cell proliferation and osteogenesis. To characterise and visualise micropore (< 20 Angstrom) to macropore (> 500 Angstrom) dimension ranges, five complementary analytical methods were applied to 58S sol-gel monoliths, each resolving different characteristics of the pore network. Nitrogen porosimetry best resolved micro and smaller mesopores (20-500 Angstrom), supplemented by helium ultra-pycnometry data. Mercury intrusion porosimetry was employed to characterise the meso and small macropores. SEM and confocal microscope imaging of the residual mercury within the matrix, provided the first visual evidence of pores within the gel-glass interstices. The network's patency was clearly demonstrated by imaging fluorochrome-labelled command-set dental dentine bonding monomers, traversing the matrix.