The purpose of this study was to evaluate leakage over time of elements from GIC in solutions with pH ranking from 2,3 to 7,3.

The samples were made with a diameter at 6,9 mm and height 2,1 mm. The cement was immediately light-cured for 20 seconds.

The samples were stored for 24 h in 100 % humidity and then placed in glass tubes (Pyrex) containing lactic acid (C3H6O3) or Tris-buffered solutions at different pH for 1, 4, and 7 days at 37 °C.

Samples exposed for 7 days were investigated using a tabletop scanning electron microscope with EDS.

Marked changes were observed in the surface of the samples stored at different pH. Quantitative energy dispersive x-ray analyses indicated predominant amounts of the elements Sr, Al and Si on the surface of the sample.

The leakage of elements increased at low pH and with longer exposure time to the solutions. For specimens kept at pH 2,3, 2,7 and 4,2 the total release of elements exceeded the limit given in ISO 22674 (200 µg/cm2). The most prominent elements released were Sr, Al and Si.


Element release from a light cured glass-ionomer at different pH
Morten Syverud, Nils Roar Gjerdet, Else Morisbak, Jan Tore Samuelsen