The effect of heat treating the glass component of a novel glass-ionomer (polyalkenoate) cement on cement properties has been determined, with specific reference to the reactivity of the glass, and the mechanical properties of the resultant cement. It has been shown that heat treatment is a suitable method of decreasing the glass reactivity and improving the handling characteristics of the mixed cement. Under some conditions, an increase in compressive strength was found, although the effect on tensile properties was not significant.