A mixture containing at least one first component A and at least one second component B, characterized in that said at least one first component A comprises a methyl methacrylate, a copolymer of methyl methacrylate dissolved in excess methyl methacrylate, optionally comprising, additionally dissolved therein, at least one polyfunctional (meth)acrylate, especially ethylene glycol dimethacrylate, butanediol dimethacrylate, hexanediol dimethacrylate, triethylene glycol dimethacrylate (TEGDMA), tetraethylene glycol dimethacrylate, diurethane dimeth-acrylate, bis(hydroxymethacryloyloxypropoxy)phenylpropane (bis-GMA), polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, ditrimethylol-propane tetraacrylateand a peroxide-based free-radical initiator, wherein said copolymer of methyl methacrylate is present in an amount of 30-50 parts by weight dissolved in a solution of 65-85 parts by weight of monomeric methyl methacrylate and 3-15 parts by weight of the polyfunctional (meth)acrylate, especially the triethylene glycol dimethacrylate (TEGDMA), mixed with a solution of 0.5 to 3 parts by weight of said peroxide-based free-radical initiator, especially dibenzoyl peroxide, in 70-90 parts by weight of monomeric methyl methacrylate, and said at least one second component B comprises methyl methacrylate and a tertiary amine.