Buffering polyacid-modified composite resins

Ion-release and buffering by polyacid-modified composite resins... 

The release of ions other than fluoride and the ability to buffer organic acids by shifting pH towards neutral is a property of glass-ionomer cements that has been known for some years [43]. Similar properties have been observed in polyacid-modified composite resins. 

Storage under both neutral and acidic conditions causes ions such as Ca +, Al +, Na+ and to be released into solution [36,40]. Like fluoride, greater amounts of all of these species are released under acidic conditions [40]. For polyacid-modified composite resins, too, storage in acidic solutions, such as lactic acid, is associated with substantial shifts in pH towards neutral [43], showing that the capability of buffering storage media is conferred by the acid-base component of the polyacid-modified composite resin. 

This ability to buffer external solutions in contact with the polyacid-modified composite resin may be a useful one under clinical conditions. The potential reduction in acidity of caries-generating acids, the main one being lactic acid, would be expected to reduce the rate of caries development in patients [44], and this would give them a useful clinical advantage over conventional composite resins. 

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