Abstract: An apparatus for producing dentures having a synthetic resin base comprises a flask tank provided with a tank closure which is opened when a flask is brought into and out of the tank and when resin is to be injected into the flask and which is closed when wax is to be removed. The flask tank has a wax pattern heater and is formed with fluid channels adapted to communicate with a resin injecting gate of the flask for successively supplying cleaning hot water, drying air and separating agent to the interior of the flask therethrough.

Abstract: A mold assembly and sprue configuration for dental investment casting includes a ring shaped casing, a base and a cover all made of resilient plastic material and fictionally engaged with each other. The base includes a raised neck having a top surface with a sighting bead for use in mounting wax forms on the sprue, positioned within the casing. The sprue includes a post for engaging a blind bore in a hub of the base. The cover includes a downwardly extending plug which extends into the body of the casing, and a curved lip with recess for facilitating the pouring of investment solution into the mold. The sprue has three spokes and a ring which are all triangular in cross-section to reduce the amount of metal needed in the precision casting to be made with the invention and also to provide a convenient flat upper surface for mounting wax forms to the sprue.

Abstract: A mold assembly and sprue configuration for dental investment casting includes a ring shaped casing, a base and a cover all made of resilient plastic material and fictionally engaged with each other. The base includes a raised neck having a top surface with a sighting bead for use in mounting wax forms on the sprue, positioned within the casing. The sprue includes a post for engaging a blind bore in a hub of the base. The cover includes a downwardly extending plug which extends into the body of the casing, and a curved lip with recess for facilitating the pouring of investment solution into the mold. The sprue has three spokes and a ring which are all triangular in cross-section to reduce the amount of metal needed in the precision casting to be made with the invention and also to provide a convenient flat upper surface for mounting wax forms to the sprue.

Abstract: A molding flask structure for molding close tolerance articles, such as prosthetic dental devices. The flask structure includes upper and lower flask members that each include cup-recesses adapted to face each other to define therebetween a mold cavity when the flask members are connected together. Assembly of the flask members is effected by a plurality of connecting bolts to securely hold the flask members together. Vent passageways are provided in the flask members to extend from the mold cavity to permit excessive internal pressures to be relieved to the exterior of the flask member. A sprue opening defined by semi-cylindrical recesses in contacting faces of each of the flask members extends from the mold cavity to the exterior to permit the introduction of molding material into the mold cavity. The sprue opening is partially threaded and partially unthreaded.

Abstract: An improved resin denture base molding apparatus for molding denture bases by injecting fused resin R into a denture base plaster mold formed in a flask F, wherein the improvement includes a table 2 provided in a manner capable of elevating up and down along a plurality of vertical guide rods 1, an elevation driving mechanism 3 for elevating the table 2, an upper support member 6 provided horizontally across each upper end of the guide rods 1 and having a through hole 4, a spring storing section 7 provided at the location of the through hole 4 on the upper surface of the upper support member 6, a push spring 8 stored in the spring storing section 7, a piston rod 10 inserted in the through hole 4 and urged downwardly by the push spring 8 and having a resin pressurizing piston 9 at the lower end thereof, a flask F placed on the table 2 and having a resin filling hole 11 at the top thereof, a cylinder 13 having a resin passage 12 that communicates with the resin filling hole 11 at the bottom wall thereof and is

Abstract: A vessel for duplicating dental models has at least two mold halves which can be clamped together. The mold halves have elements for mutually centering and for securing the model to be duplicated, for example, a tooth stump or the like. The vessel further includes an intake funnel each for pouring in liquid silicone and refractory casting material. A foil insert is provided in the plane of separation of the two mold halves when the vessel is closed. The foil insert has a thickness which corresponds in size to the setting expansion of the refractory casting material. The model to be duplicated is located in the center axis of the vessel and extends approximately by half its length through the foil insert and is held in position by the foil insert.

Abstract: A mold for manufacturing a skin covered foamed plastic article in which the middle mold is to be attached to the upper mold so as to eliminate the attaching and removing of the middle mold for every manufacturing cycle, without creating a danger of damaging the manufactured skin covered foamed plastic article in taking it out of the mold. The mold includes a middle mold to be attached to the upper mold such that when the upper mold is lifted upwards in order to be disassembled from the lower mold, the middle mold also moves upwards and the skin covered foamed plastic article is taken out from the lower mold by the upper mold and the middle mold; and a protrusion for making a hole in the skin covered foamed plastic article to be manufactured, to be attached to the molding surface of the lower mold, which is freely detachable from the lower mold such that when the upper mold is disassembled from the lower mold, the protrusion is taken off the lower mold along with the skin covered foamed plastic article.

Abstract: A method of producing resin articles by use of a plaster mold in which the resin injection pressure in the plaster mold is sensed by a pressure sensing means to control the injection conditions for a molding machine in accordance with the desired injection speed, injection pressure, and holding time, as determined by the size and shape of the article being molded and the diameters of a sprue runner and an air vent. Heating and cooling pipes may optionally be embedded in the plaster to accelerate the setting of the resin in any thick portions while maintaining the resin in the sprue runner position of the mold sufficiently fluid so that additional resin may still be injected into the mold to compensate for any shrinkage. The molded products may be dental prosthetic goods of intricate shape and having increased strength and improved dimensional accuracy compared to those fabricated by previous methods.

Abstract: A system and method is disclosed for obtaining precisely registered, articulated castings of upper and lower dental impressions. The dental impressions are obtained through use of a dental tray having a non-porous, bite-deformable central septum. The impression material for the upper dental impression is contained in the upper portion of the tray. The impression material for the lower dental impression is contained in the lower portion of the tray and is supported by a bottom cover which is removed subsequent to placement of the tray in the mouth. As the patient bites, the impression material in the upper and lower portions of the dental tray is molded to the contour of the teeth and gums in their proper relationship with the teeth closed. After the material has set, the tray containing registered upper and lower impressions is removed from the mouth and placed into a mold.