A denture made by moulding a mixture of liquid monomer and p  solid polymer is provided with a sheet of soft resilient plastic which forms that surface of the denture that is in permanent contact with the tissues of the mouth, the sheet being put in the mould with the mixture and moulded therewith.  The sheet adheres strongly to the polymerized moulded mixture.  The sheet may be made from co-polymers of lower methacrylic acid esters (e.g. methacrylic acid methyl, ethyl or iso-pentyl ester) with one or more other vinyl compounds which when polymerized by themselves yield soft plastics (e.g. acrylic acid butyl, hexyl or octyl ester or methacrylic acid octyl or n-lauryl ester).  The polymerization of these co-polymers may be carried out in the presence of polyfunctional vinyl compounds, e.g. divinyl benzene, glycol dimethacrylate or diacrylate, or butanediol or hexanediol dimethacrylate, whereby cross-linked polymers are obtained. Thus, a sheet or foil may be made by pearl polymerizing at 80 DEG C. in the presence of benzyol peroxide either a 35:65 mixture of methacrylic acid methyl ester and acrylic acid ester or a 35:64:1 mixture of methacrylic acid methyl ester, acrylic acid butyl ester and glycol dimethacrylate, and moulding at 150 DEG C.  The second mixture gives cross-linking.  In one example a dental mould is packed with a plastic mixture containing monomeric and polymeric methacrylic acid methyl ester as in Specification 484,343, closed and opened. Excess mixture is removed, a cut piece of 0.3 mm. thick foil of the 35:65 co-polymer described above is placed over the mixture to cover it completely, the whole is moulded and the mould is immersed in boiling water.  A two-layer denture is thus produced.  The soft co-polymer lining may be trimmed.  In another example a foil 1 mm. thick is used.  In a further example the monomer/polymer mixture comprises a powder consisting of 2 parts by weight of after-chlorinated and densified polyvinyl chloride, 1 part of methacrylic acid methyl ester pearl polymer, 0.15 per cent. cadmium red, 0.15 per cent. titanium dioxide and 0.5 per cent. benzoyl peroxide, the powder being kneaded with liquid monomeric methacrylic acid methyl ester in a proportion of 3 parts of powder to one part of liquid.  Specification 701,122 also is referred to.ALSO:A denture made by moulding a mixture of liquid monomer and solid polymer is provided with a sheet of soft resilient plastic which forms that surface of the denture that is in permanent contact with the tissues of the mouth, the sheet being put in the mould with the mixture and moulded therewith.  The sheet adheres strongly to the polymerised moulded mixture.  The sheet may be made from co-polymers of lower methacrylic acid esters (e.g. methacrylic acid methyl, ethyl or iso-pentyl ester) with one or more other vinyl compounds which when polymerized by themselves yield soft plastics (e.g. acrylic acid butyl, hexyl or octyl ester or methacrylic acid octyl or n-lauryl ester).  The polymerization of these co-polymers may be carried out in the presence of polyfunctional vinyl compounds, e.g. divinyl benzene, glycol dimethacrylate or diacrylate, or butanediol or hexanediol, dimethacrylate, whereby cross-linked polymers are obtained.  Thus, a sheet or foil may be made by pearl polymerizing at 80 DEG C. in the presence of benzoyl peroxide either a 35:65 mixture of methacrylic acid methyl ester and acrylic acid ester or a 35:64:1 mixture of methacrylic acid methyl ester, acrylic acid butyl ester and glycol dimethacrylate, and moulding at 150 DEG C.  The second mixture gives cross-linking.  In one example a dental mould is packed with a plastic mixture containing monomeric and polymeric methacrylic acid methyl ester as in Specification 484,343, [Group IV], closed and opened.  Excess mixture is removed, a cut piece of 0.3 mm. thick foil of the 35:65 copolymer described above is placed over the mixture to cover it completely, the whole is moulded and the mould is immersed in boiling water.  A two-layer denture is thus produced.  The soft co-polymer may be trimmed.  In another example a foil 1 mm. thick is used.  In a further example the monomer/polymer mixture comprises a powder consisting of 2 parts by weight of after-chlorinated and densified polyvinyl chloride, 1 part of methacrylic acid methyl ester pearl polymer, 0.15 per cent. cadmium red, 0.15 per cent. titanium dioxide and 0.5 per cent. benzoyl peroxide, the powder being kneaded with liquid monomeric methacrylic acid methyl ester in a proportion of 3 parts of powder to one part of liquid.  Specification 701,122, [Group IV (a)], also is referred to.ALSO:A denture, made by moulding a mixture of liquid monomer and solid polymer is provided with a sheet of soft resilient plastic which forms that surface of the denture that is in permanent contact with the tissues of the mouth, the sheet being put in the mould with the mixture and moulded therewith.  The sheet adheres strongly to the polymerized moulded mixture.  The sheet may be made from co-polymers of lower methacrylic acid esters (e.g. methacrylic acid methyl, ethyl or iso-pentyl ester) with one or more other vinyl compounds which when polymerized by themselves yield soft plastics (e.g. acrylic acid butyl, hexyl or octyl ester or methacrylic acid octyl or n-lauryl ester).  The polymerization of these co-polymers may be carried out in the presence of polyfunctional vinyl compounds, e.g. divinyl benzene, glycol dimethacrylate or diacrylate, or butanediol or hexanediol, dimethacrylate, whereby cross - linked polymers are obtained. Thus, a sheet or foil may be made by pearl polymerizing at 80 DEG C in the presence of benzoyl peroxide, either a 35 : 65 mixture of methacrylic acid methyl ester and acrylic acid ester or a 35 : 65 mixture of metacrylic acid methyl ester and acrylic acid ester or a 35 : 64 : 1 mixture of methacrylic acid methyl ester, acrylic acid butyl ester and glycol dimethacrylate, and moulding at 150 DEG C.  The second mixture gives cross-linking.  In one example a dental mould is packed with a plastic mixture containing monomeric and polymeric methacrylic acid methyl ester as in Specification 484,343, [Group IV], closed and opened.  Excess mixture is removed, a cut piece of 0.3 mm. thick foil of the 35 : 65 co-polymer described above is placed over the mixture to cover it completely, the whole is moulded and the mould is immersed in boiling water.  A two-layer denture is thus produced. The soft co-polymer lining may be trimmed.  In another example a foil 1 mm. thick is used.  In a further example the monomer/polymer mixture comprises a powder consisting of 2 parts by weight of after-chlorinated and densified polyvinyl chloride, 1 part of methacrylic acid methyl ester pearl polymer, 0.15 per cent cadmium red, 0.15 per cent titanium dioxide and 0.5 per cent benzoyl peroxide, the powder being kneaded with liquid monomeric methacrylic acid methyl ester in a proportion of 3 parts of powder to one part of liquid.  Specification 701,122, [Group IV(a)], also is referred to.