REACTIVITY OF FLUORIDE-CONTAINING CALCIUM ALUMINOSILICATE GLASSES USED IN DENTAL GLASS-IONOMER CEMENTS

The glass component critically determines the properties of glass-iono mer cements (GIC). However, the exact relationship between the composi tion of the glass and these properties is not yet fully understood. To investigate this relationship, we studied the reactivity of glasses u sed in commercial GIC in acetic acid solutions, using a pH-stat method . Qualitative differences in the leaching behavior of these glasses ca n be explained by different pre-treatments. Acid-washing and silanizat ion modify the surfaces of the glass particles, thus inducing a delay of the leaching process, whereas untreated glasses exhibit a fast init ial leaching, but their acid reactivity slows very soon. Quantitative differences in acid reactivity can be correlated with the mean chemica l composition of the glasses. In this respect, the leaching tends to i ncrease with an increasing ratio of network-dwelling cations to Al3+ i ons. These results provide a fundamental basis for the explanation, pr ediction, and control of cement properties as a function of glass char acteristics.