Dimensional behaviour of dental composites due to polymerization shrinkage and water sorption

The dimensional changes with respect to time of five typical dental restorative composites due to polymerization shrinkage and water sorption were investigated for a period from 90 seconds up to half a year after starting the polymerization process. The aim was to examine the contention that the swelling by water sorption compensates for the shrinkage. It was shown that in no case could this assumption be confirmed, but reduction of the shrinkage by water sorption amounts to one third at maximum.