Abstract: The physical properties, especially resistance to abrasion, to bending and to pressure, of plaster models for use in dentistry are improved in that a plaster model obtained in a manner known in the art is impregnated with (a) at least one photopolymerizable ester of acrylic and/or methacrylic acid, (b) at least one photopolymerization initiator, and (c) optionally at least one photopolymerization activator--(a), (b) and (c) being present in liquid or dissolved state--and the impregnated plaster model is irradiated with light suitable to initiate photopolymerization by the photoinitiator.