Abstract: Prosthetic dental appliances of stable color and good mechanical properties can be produced by photopolymerization of one-component preparations which are stable during the storage, on the basis of ethylenically unsaturated monomers as well as fillers and dyes when using bicyclo-[2.2.1]-heptane-dione-2,3 compounds, if necessary together with amines, as photoinitiators for achieving sufficient penetration of the polymerization and whose inherent yellow color after short primary irradiation with visible light is bleached out for fixation permanently by intensive postirradiation with visible light.