Characterisation of the ultrastructure of glass-ionomer (poly-alkenoate) cement.

Set glass-ionomer cements were sectioned with a diamond knife and examined in the transmission electron microscope. Their appearance was in accordance with the theoretical structure of these materials, close examination revealing glass particles surrounded by a siliceous layer set in a hydrogel matrix. The elemental composition of each region was determined by X-ray microanalysis (energy dispersive). The results of microanalysis supported the ultrastructural observations, with ions that originated from the glass particles being detected throughout the matrix of the set cement. It was suggested that the mobility of these ions in the matrix phase was important in determining the biocompatibility and adhesive properties of glass-ionomer cements.