New method for monitoring the reaction of glass-ionomer cements: a spectroscopic study of the effects of polyacid structure on the decomposition of calcium aluminosilicate glasses

A method has been developed that permits monitoring of the reaction of basic glass powders with various polyacids during the formation of glass-ionomer dental cements. Decomposition of the calcium aluminosilicate glass is followed via laser-induced emission signals from trace elements introduced into the powder with the aluminum oxide component or from imperfections in the glass matrix. The method that is reported is significantly easier than previously reported methods and does not require the reaction to be quenched. The change in the intensity of the emission bands was correlated with the extent of branching in the side chains of seven polyacids, indicating that the structure of the polyacid affects the rate of decomposition of the glass powders. The polyacids with longer side chains and more branching extract metal ions from the glass powder more efficiently than the conventional polyacids that have reactive carboxylic groups attached uniformly and directly on the polymer backbone.