Some aspects of solubility of silicate and glass Ionomer cements a Laboratory Study

Abstract

Three aspects of the in-vitro solubility of silicate and glassionomer dental cements were studied. a) The solubility of silicate cements was studied using the "weight of evapourated eluate method. It was shown that the dissolution of these cements depends on the volume of solution in which they are immersed and also the frequency in which this was changed. It was seen that these cement~ were capable of taking up fluoride ions from concentrated solutions while releasing the same ions in more dilute solutions. Studies with samples of varying surface area:volume ratios confirm that dissolution is not only dependent on the surface area but that matter is also lost from the bulk of the specimen. b) The release of organic materials from glass ionomer cements immersed in water or phosphate solution was studied using a total organic content (T.O.C) analyser. It was seen that upto 0.l0mg of organics could be detected in such solutions. The concentration of detected organic species rises with increasing time, then falls off again. This is explained in terms of re-adsorption of the organic species by the cement. c) Thermogravimetric analysis studies glass ionomer cement samples " with various histories were made. Weight loss (presumably of water) was shown to be related to the history of the samples as well as to the thermogravimetric conditions. The thermogravimetric conditions used in this study were air and Nitrogen atmospheres. The results are used to assess the merits of the

sample-weight loss" method for investigating solubility. This method, in view of the simultaneous water loss or uptake by the sample, is not recommended.