Dentures and process for making the same

The process for making a denture comprising teeth imbedded in a hard non-hydrophilic polyurethane elastomer tooth-holding portion integrally chemically bonded to a soft non-hydrophilic polyurethane mouth-engaging portion into a unitary mass from a model assembly comprising a mouth model having mounted thereon a wax replicate denture, which comprises coating the mouth model and wax replicate denture portions of the model assembly with a release material except for the ends of the teeth, and imbedding it in investment material to form a mold having a cavity corresponding to the wax replicate denture, allowing or causing the investment material to set up, removing the mouth model and the wax of the wax replicate denture therefrom, leaving the teeth positioned in the bottom of the cavity of the female mold, applying a wax shim to the portion of the mouth model previously occupied by the wax replicate denture, assembling the mouth model and female mold to form a denture mold, filling the thus formed denture mold with hard non-hydrophilic polyurethane elastomer-forming material and allowing or causing it to set up to form hard non-hydrophilic polyurethane elastomer, removing the wax shim from the denture, filling the space vacated by the removal of the wax shim with soft non-hydrophilic polyurethane-forming material and allowing or causing the same to set up therein to form soft non-hydrophilic polyurethane elastomer and to integrally chemically unite with the portions of the hard non-hydrophilic polyurethane elastomer teeth with which it is in contact to form a unitary mass, removing the cast denture from the mold and finishing them as needed.