A narrow channel is provided in the abutment mating surface of a dental prosthesis undercase to allow excess dental cement to flow out of the interstitial space between the dental abutment and the overlying prosthesis. During the seating of the prosthesis the excess dental cement is channeled to and extruded from a preferred collection point for easy removal. Hydrostatic pressure and trapped gases that would tend to lift the prosthesis into a non-fitting position or form a weakened cemented bond of uneven thickness are prevented by this apparatus and method. A positive copy of the narrow channel is attached to the lingual aspect of the abutment analog of the model. A virtual hydrostatic groove and lingual shelf can be subtracted from a virtual model of undercase for manufacture using computer modeling.