CHEMICAL PREPARATIONS FOR INDUSTRIAL USES-NAMELY, PLASTICS IN THE FORM OF PASTE OR POWDER 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 MODELING MATERIAL FOR DENTAL USES, TOOTH FILLERS, TOOTH LACQUERS, INSULATING AGENTS FOR DENTAL PURPOSES-NAMELY, SUCH FOR GYPSUM MODELS FOR USE IN THE MANUFACTURE OF PLASTIC PROSTHESES AND INJECTIONS FOR DENTAL USES