Setting Shrinkage and Hygroscopic Expansion of Resin-modified Glass-ionomer in Experimental Cylindrical Cavities

Abstract

The effects of the C-value (bonded surface area/unbonded surface area) and the volume of the cavity on the volumetric dimensional changes [volumetric setting shrinkage (VSS) and volumetric hygroscopic expansion (VHE)] of a resin-modified glass-ionomer (RMGI) filled in experimental cylindrical cavities were evaluated. The VSS and the VHE rate decreased with increasing C-value. There was a high inverse regression between the cavity C-value and volumetric dimensional changes, but a low regression between cavity volume and volumetric dimensional changes. Therefore, it was thought that greater contraction stress would remain in high C-value cavities than low C-value cavities during the setting process. It was also confirmed that the volumetric dimensional changes of RMGI in cavity were influenced primarily by the cavity C-value.