This in vitro study was carried out to investigatethe impact of varying phosphate fractions on
pH changes of storage solutionof artificial saliva and weight changesforfour experimental
ionomer cements at specific time intervals.Three disc-form specimens for each composition
were prepared, weighed-out (initial weight = W0) and then immersed individually in 10 ml of
artificial saliva (initial pH = 6.5) for the experimental periods at 37oC. At 7, 14 and 28 days,
the final pH values of artificial saliva solutions were measured using a pH electrode meter.
The discs were immediately collected, dried and re-weighted (final weight = W1) to calculate
the weight changes by percentage.All tested cements were bringing the pH slightly down
towards the acidity level after 7 days, and then the values became relatively stable when the
time progressed further up to 28 days. As well, thedatashowed that the less phosphate was
added to the basic ionomer glasses, the lessinfluenceon pH rate was evaluated. A linear
relationship between the pH values as a function of phosphate content was obtained at all
time points. In terms of weight changes, there was a moderate increase in the mass during the
entire experimental period.The extent of the changes in pH values of artificial saliva and in
specimens weightsled to the conclusion that the ionomer glass components has a crucial role
in controlling the material behaviour. Further studies have to be done.
Keywords: Ionomer Cements; Phosphate; pH Changes; Weight Changes; Artificial Saliva

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