The composition, leachable products, and physical properties of toothcoloured restorative materials have been determined. The composition was often found to be more complex than described in the MSDS of the materials. The most frequently used monomers such as TEGDMA, Bis-GMA, Bis-EMA, UDMA, and 2-HEMA were detected, as well as several other monomers and different additives (initiators, activators, and stabilizers). The initiator camphoroquinone was found in all the investigated materials. B