Abstract: A device for receiving dental investment solution to create an investment mold, has an oval casing which fictionally engages an oval base. Anti-rotation tabs of the base extend into anti-rotation slots in the casing, with both casing and base made of flexible plastic material.

Abstract: The subject matter of the invention is a casting ring former for forming molds for dental prosthesis products, such as artificial teeth, dental bridges, etc. The casting ring former according to the invention, which represents an improvement with regard to the casting cuvettes known so far is characterized in that they are removed from the mold prior to heat treatment, solves the given technical problem through the use of a specially formed base which may be provided with two nipple-shaped protuberances and two oppositely lying bulges according to a first variant, or up to three pairs of nipple-shaped protuberances and oppositely lying bulges according to a second variant, where in the base thus formed an undulate tape is placed and removed after the mold has cooled and the mold is taken off the base.

Abstract: In a dental prosthetic casting-on process, in which a secondary part made of metal is cast-on to a primary part made of metal, a primary part made from an oxide-forming metal alloy may be used if the latter's casting-on surface is alloyed, prior to casting-on, with a reducing metalloid. In this regard, boron, silicon or phosphorus, for example, can be made to diffuse into the surface lattice of the primary part. A primary part made from an oxide-forming dental alloy and suitable for such a casting-on process exhibits in its casting-on surface an enhanced boron or silicon or phosphorus content.

Abstract: A method of making a dental prosthesis by forming a model of a tooth stump, coating with a layer of electrically conductive material, galvanically plating over the conductive material with a layer of copper, exposing occlusal surfaces of the model, coating the exposed occlusal surfaces of the model with an electrically conductive material followed by a galvanic plating on the model occlusal surfaces, and separating the copper layers form each other at about the tooth equator into an occlusal mold/electrode and a stump mold/electrode. The electrodes are used in a spark erosion process to form a dental prosthesis from a solid matrix body.

Abstract: The production of high precision molds and castings for dental prosthesis and the like is enhanced with a casting ring and sprue former base constructed of a clear expandable thermoplastic. The ring and base are telescopically interlockable with each other to define a vessel containing a mold form strategically disposed therein so that as investment solution poured throughout is able to cure without detracting from the precise measurements of the mold form to provide a true mold from which precisely dimensioned castings are formed.

Abstract: A casting mold for the production of muffles which serve for the conversion of wax models to metal, with the casting mold having a funnel shaper (1) which consists of a disk-shaped base plate (4), at the circumference of which a side wall (5) which stands vertical to the base plate (4) runs, and a cone (6) arranged in the center of the base plate (4), pipe-shaped, muffle ring (2) partially inserted into the funnel shaper (1), with the outside wall of the muffle ring (2) resting against the inside circumference of the side wall (1) of the funnel shaper (1), a cylindrical ring (7) which is inserted on the side of the muffle ring (2) which faces the funnel shaper (1) and the central opening (8) of which surrounds the cone (6), and a blind funnel (3) provided on the side of the muffle ring (2) opposite the funnel shaper (3), whose funnel tip faces towards the cone (6 ) of the funnel shaper (1).

Abstract: A dental investement composition in the low-dusting powdery form contains (a) a mixture of a soluble phosphate with magnesium oxide or hemihydrate gypsum as a binder, (b) quartz and/or christobalite as a refractory material, (c) one or more wetting agents selected from the group consisting of hydrophobic liquid hydrocarbons, liquid hydrophobic fatty acid esters and liquid hydrophobic fatty acids showing a vapor pressure of 3.15 mmHg or below 20.degree. C., and (d) one or more anionic surface active agents selected from the group consisting of alkylbenzene sulfonates and alkyl sulfates.

Abstract: A cushioning sheet made of a flammable material for use, e.g. in denture casting. It is inserted into a casting frame and adapted to burn out when heated to leave a space between a casting frame and a casting mold in the frame. The space serves to absorb the difference in the thermal expansion between the frame and the mold, thus preventing the casting mold from cracking or breaking. The cushioning sheet is formed with apertures. The casting material penetrates through the apertures, abutting against the casting frame to support the casting mold upon the frame even after the cushioning sheet has burnt out.

Abstract: A denture base of pressure-formed, superplastic alloy plate, and a method of making a metal denture base, includes providing a superplastic alloy plate and a female die having a finishing surface, and pressure-forming the alloy plate on the finishing surface of the female die at a temperature where the alloy exhibits superplasticity.

Abstract: Gate is a wax structure for forming part of a wax master in investment casting of a dental prosthesis. The gate has a square feeder with a circular disc on each end. The square feeder reduces the cracking stresses between adjacent feeders to reduce unwanted fins, and the square shape aids in final cutoff of the cast prosthetic. In the wax master, one of the discs is secured to the prosthetic form and the other disc to the conventional reservoir bar. The disc shape aids in filleting to the form and bar.

Abstract: The wax master sprue and runner or gate form used in the investment casting process of dental prostheses has a web between the runners or gates so that the runners or gates are secured together to prevent shifting of the runners or gates during the molding of the casting material around the wax master.

Abstract: A spruing assembly for receiving investment material in the production of an investment mold for castings by the "lost wax" process which includes a hollow chamber to receive the investment material formed by a base member and an engaging tapered ring. A horizontal feeder bar is contained within the chamber and is supported by hollow sprue means. The feeder bar is open at its top and has a narrow channel for conducting molten wax into the hollow sprue support. The base member includes a centralized sprue base former and support means associated with the former to provide support for the hollow sprue means supporting the feeder bar.

Abstract: A pad eliminatable by heat prior to casting has a patterned surface and a non-porous backing. The pad is sized and shaped into at least part of the appliance and the patterned surface is conformed to the desired bonding surface contour. The patterned surface yields irregularities in the cast bonding surface which increases bondability.

Abstract: A metallic base dental prosthesis having an improved fit resulting from the cavity and rim portions of the prosthesis being finish machined by electric discharge machining (EDM).

Abstract: A method of making a form of a desired shape, for use in an investment casting technique which comprises forming a first sheet of formable material to a shape which approximates to the desired shape of the form, disposing the formed shape around a layer of deformable hardenable material, applying a compressive force to the formed shape to deform the underlying hardenable material to a desired shape, hardening the hardenable material to produce a form precursor, removing the formed shape from the hardened form precursor and utilizing the hardened form precursor to form a second sheet of formable material into the form of the desired shape. The invention also includes a method of making crowns by an investment casting technique utilizing the form produced by this method.

Abstract: A precision investment casting assembly has a model support consisting of a central upstanding sprue former and outwardly extending tubes to support wax models. The sprue former is held at one end by a resilient base. A somewhat key-hole shaped recess in the base receives a split flask which encircles the support. An elongated pin engages the free edges of the split flask to close it while embedment material is poured around the support. The pin is removed to release the flask from the embedment material after casting. Proper orientation of the support elements is aided by a plurality of keys and keyways.

Abstract: A synthetic sprue forming assembly comprises a base or preform adapted for engagement with a crucible former, a plurality of sprue formers, and one or more conduit forming shafts extending between the base and sprue formers. Each sprue former consists of a first portion connected to a shaft, a gate portion, and an enlarged reservoir portion therebetween. In one embodiment, there are a pluality of integral sprue pins seated in recesses in the base and each comprising a shaft portion and a sprue former portion extending at an angle to the longitudinal axis of the shaft. In another embodiment, there is one large shaft integral with the base, and the reservoir and gate portions are integrally formed and rotatably and detachably mounted to a conduit portion on the large shaft. In the method of making an investment mold, the base and sprue formers are assembled on a crucible former in an investment mold container.

Abstract: An improved investment casting process for producing dental restorations, particularly a dental crown, comprising the steps of fixing a wax pattern onto a truncated cone in a metallic ring having a lining of a cushioning material, pouring an investment material into the space around the wax pattern in the metallic ring, drying the resultant product, melting out the invested wax pattern, curing the resultant product at a temperature of 700.degree. to 950.degree. C for 20 to 150 minutes to give a mold, fixing the mold thus obtained to a centrifugal casting machine and casting a molten chromium-cobalt and/or nickel alloy in the mold maintained at a temperature of 100.degree. to 500.degree. C.

Abstract: A pattern set-up especially useful for making prosthetic dental appliances is assembled by attaching a plurality of refractory casts to a support member so that adjacent casts along the length of the support member are circumferentially offset with respect to one another. The casts carry expendable patterns that are connected to the support member by gating systems laid down on faces of the casts. The support member has outward protrusions supporting the weight of the casts and may be formed by a plurality of segments fitted together in end-to-end relation.

Abstract: A casting machine including a control circuit which automatically controls ts operation. The casting machine includes a casting chamber which supports an alloy filled open-ended container whose open end faces the sprue hole of an investment casting ring. The control circuit couples a vacuum to the casting chamber while maintaining the casting chamber in its initial upright position. After a first timing interval, the chamber is inverted and the vacuum is decoupled from the casting chamber, and compressed air is applied to the casting chamber. After a second subsequent time interval the casting chamber is automatically returned to its initial upright position, the action of which causes the casting chamber to be automatically vented to the atmosphere.

Abstract: Precision investment casting of small parts with fine detail and free of air inclusions is achieved by the use of flat sided blocks of a relatively high melting point plastic material received upon elongated tubes or rods of the same or similar material. The shape and size of the blocks permit a large number of small parts to be cast at the same time and provide reservoirs for the molten casting metal close adjacent the casting cavity.

Abstract: In the manufacture of a mould by the so-called lost wax method, the position and space occupied by a set of blank-carrying elongate members of fusible or calcinable material supported on an ogival head or cone are controlled by a gauge including a ring slidably mounted along a vertical rod. The gauge is then replaced by a cylinder forming a receptacle which receives a hardenable refractory material embedding said set. After hardening, the cone is removed and the fusible or calcinable material removed by heating to provide mould cavities.