Polymerizable isocyanurate monomers and dental compositions are described. A hardenable dental composition is described comprising at least one isocyanurate monomer that is a stable liquid at about 25° C. The isocyanurate monomer comprises at least one divalent linking group bonded to a nitrogen atom of a trivalent isocyanuric acid ring, wherein the divalent linking group comprises a moiety selected from ester, thioester, ether, or thioether, and combinations of such moieties and a terminal ethylenically unsaturated polymerizable group.