Abstract The aim of this study was to investigate the influence of size and shape of ceramic filler in dental composites on polymerization shrinkage. Moreover, the influence of resin shrinkage itself on the whole composite shrinkage was investigated. In 3D linear elastic finite element analyses, the process of shrinkage of dental resin/ceramic composites during polymerization was simulated using the ANSYS software. Composites were modelled with volumetric content of ceramics ranging from 0 up to 45%. Aggregates with different shape and size were analysed. Quantitative estimates have been obtained of the reduction in composite shrinkage with increasing content of ceramic aggregate or decreasing shrinkage of the resin. It has been found that by adjusting aggregate size and resin shrinkage a lower shrinkage of the dental composite may be obtained.