IMPRESSION MATERIAL FOR DENTAL USES [ -NAMELY, PLASTICS IN PASTE OR POWDER FORM AND MATERIAL MAINLY CONSISTING OF PLASTICS IN PASTE OR POWDER FORM FOR THE MANUFACTURE OF TOOTH CROWNS, TOOTH BRIDGES, ARTIFICIAL TEETH AND PLASTIC PROSTHESES; PLASTICS AS MODELLING MATERIAL FOR DENTAL USES, IMPRESSION MATERIAL FOR DENTAL USES, TOOTH FILLERS, TOOTH LACQUERS; INSULATING MATERIALS FOR DENTAL-TECHNICAL PURPOSES-NAMELY, GYPSUM MODELS FOR USE IN THE MANUFACTURE OF DENTAL PROSTHESES MADE OF PLASTICS ]