Direct surface pH determinations of setting cements.

Surface pH measurements were made over a 24-hour period for several luting cements and glass-ionomer lining and restorative materials. Of the luting cements, the water-mixed glass-ionomer cement, Ketac-Cem, had the lowest initial pH and the polycarboxylate, Durelon, had the highest. Three glass-ionomer lining materials showed differences in pH that increased over the entire test period. Two of the three visible-light-cured glass-ionomer liners evaluated showed similar pH values, while the third exhibited a considerably lower pH. The lower pH values found with the water-mixed glass-ionomer luting agent suggest that acidity may contribute to the posttreatment sensitivity associated with this material.