Abstract: Apparatus useful in forming a mold from a wax pattern in an investment casting process, the invention provides a loop element having arm elements which spiral downwardly from and inwardly of the loop element to a base element. Sprue pins mount wax patterns to the loop element in a casting process known as the "lost wax" technique, the apparatus of the invention being particularly useful in the environment of a dental laboratory for formation of crowns and the like of high density. The loop element and arm elements of the apparatus leave channels in the investment material on "burn out" which quickly accelerate a casting material, such as a metal alloy, into the formed mold or molds with a reduction of turbulence which results in fewer defective castings. The channel geometry provided by the apparatus provides benefits due to a lack of right angles or sharp corners which restrict the flow of casting material into the mold or molds.

Abstract: Methods for performing operations on a die or dental model including the filling in or "basing up" of voids, deep areas and undercuts; the indexing and investment soldering of dental crowns from a die model; and aid in the fabrication of porcelain jacket crowns and the like; the invention particularly contemplates the use of a cyanoacrylate compound to effect said methods. According to the present methods, a high viscosity cyanoacrylate base material, typically the methyl or ethyl ester of the cyanoacrylate is deposited on the die model in the areas which are to be based up, blocked out or the like, an activator or accelerator compound such as an aromatic amine or the like being then sprayed, preferably in an atomized mist form, onto the deposited base material.