Dimensional changes occurring in a glass-ionomer cement.

The dimensional changes occurring when glass ionomer cements are exposed both to desiccating and moist conditions were investigated. All work was done at 23 degrees C. The effect of time allowed for cements to mature before exposure to the test conditions was studied as was the effect of adding cellulose ethers. The contraction of glass ionomer cements under desiccating conditions was far greater than the expansion by water absorption. Increase of the time allowed for the cements to mature reduced the extent of this effect markedly. The addition of cellulose ethers to cement mixes was only moderately effective in reducing dimensional change.