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.