In an exemplary embodiment, a method of creating an impression of structures of the human oral cavity comprises: preparing impression trays creating a first, or base, impression grinding out portions of the base impression and using the void(s) in the ground out base impression to take a second, or wash, impression. The base impression is taken with an excess of a high-density impression material which is positioned to extend beyond the structures of interest (of which the impression is being taken). The base impression is removed and all fine structure surrounding the structure(s) of interest is ground out. A wash impression is then taken using a low-density impression material. The base impression creates a seal around the structure(s) of interest (a closed system), thereby producing omnidirectional hydraulic pressure on the low-density material. Such omnidirectional hydraulic pressure produces a highly detailed final impression from which a high-quality model (e.g., cast) can be made.
