Abstract: A mould for an injection moulding apparatus, the mould including at least two mould parts which mate to form the mould cavity and which separate to permit removal of the moulded article, each mould part including a relatively rigid body having an abutment face which abuts with an abutment face of the other mould part when said parts mate, the body of at least one mould part including a recess in its abutment face which is filled with a resilient material defining a portion of said mould cavity.

Abstract: A method for forming a part inserted in the auditory canal of a hearing impaired person, said part being either an otoplastic or a carrier part of the hearing aid insertable into the auditory canal or an ear adaptor member for a hearing aid to be worn behind-the-ear, characterized by providing an expandable elastic member, coating said elastic member with a hardenable material, inserting the coated member into an ear of the person who is hearing impaired, allowing the hardenable material to harden to retain the outside contour of the part. The elastic expandable member may be either a porous member which is partially saturated on the outer surfaces or may be a smooth member which is coated with the hardenable material. If desired, a physiologically compatible coating may be applied onto the hardened surface layer subsequent to the hardening process.

Abstract: An apparatus for manufacturing an otoplastic. An otoplastic is manufactured directly in the ear of a hearing-impaired person in that a deformable envelope is pulled over a die or over a shell or over an overlayed over-shell. This apparatus is then supplied with flowing otoplastic material between the die and the envelope, being supplied therewith in the ear. The envelope expands and assumes the shape of the auditory canal. After hardening or curing of the otoplastic material in the ear of the hearing-impaired person, the envelope and the die are removed and a module of either an in-the-ear or of a behind-the-ear hearing aid is integrated therewith.

Abstract: A system is provided for generating prescription wheelchair seats or specialized seating or body supports. The system includes a deformable seat portion which is formed to specialized dimensions of a seated patient. A planar, linear, array of linear transducers is stepped across the form in one dimension forming a series of signals representative of generally planar cross sections of the form. This series of cross-sectional signals is provided as an input to a numerically controlled cutting device which cuts a series of sheet stock foam in accordance with each cross-sectional area measured. These cross-sectional pieces are then assembled into the prescription seat.

Abstract: A method is disclosed for making a facial and/or body prosthesis or appliance by means of molding and forming techniques. The material formed into the final prosthesis is a specific material uniquely adapted for the purpose. The material is a closed-cell, cross-linked, polyethylene and is in sheet form having a thickness in the range of from 1/64 inch to 1/4 inch and a density of between 11/2 and 9 pounds per cubic foot. The disclosure also includes the prosthesis per se as well as the method of making up a human face or body with the use of the prosthesis.

Abstract: The grip is comprised of a deformable cover formed of a thermoplastic material which is stable and semi-rigid at normal ambient temperatures and is soft and deformable when heated in boiling water. The cover is attached to an implement handle heated and deformed to the shape required by a specific implement user. The method of forming the grip includes the steps of coating the implement handle with a cover material, heating the implement handle until the material has become softened, and grasping an implement handle while the cover is soft and deformable, thereby causing the cover to be molded to a user's specific shape. The high coefficient of friction and the moldability of the material results in a superior grip.

Abstract: A method is disclosed for constructing a glass mould, and particularly the primary glass mould member, for use in casting multifocal, ophthalmic lenses from organic polymers. The method comprises pressing a glass segment with a cavity, removing the base portion of the segment to form a perforation, mounting the perforated segment on a second glass body, and fusing the assembly to form a blank for finishing. For trifocal lenses, a composite, perforated segment is formed and sealed in a depression on a major element to form a blank.

Abstract: A method to obtain corrected impressions of the foot so as to produce corrective soles including two or three superimposed rigid frames connected to a supporting structure secured by arms of different length joined to the supporting structure. Each frame is equipped with two flexible walls which, along with the frame, delimit a sealed enclosure filled with a granular material, the enclosure communicating with a suction device.

Abstract: A customized spinal orthotic device is provided to enhance spinal adjustment and manipulative procedures. The embodiment of the orthotic device shown and described is a plastic head and cervical basin which is enclosed in a plastic bag. The patient is placed in a supine position with the head and cervical spine portion received within the plastic basin but exterior of the bag. Commercial flexible polyurethane foam A and B components are mixed and placed in the bag-enclosed basin. The A and B components react exothermically to expand and to apply pressure to the cervical spine portion contained within the basin. In about fifteen minutes the polyurethane hardens to form a foam mold for the posterior apophyseal joints of the cervical spine and in the process urges the joints of the spine into their normally aligned positions. The mold may then be used by the patient on a daily basis within the purview of a clinical care program to enhance the effect of the spinal adjustment and/or manipulative procedure.

Abstract: To adjust eye-glasses to the special shape of the nose of the person wearing the eye-glasses, a faithful molding of the back of the nose is formed. To this effect, once the spectacles are put on, the space remaining between the spectacle arch (4) and the back of the nose is filled with a plastic and hardenable molding material. The spectacle arch (4) is embedded into the hardened molding material to form a plaster model (6). After having removed the molding material, the cavity separating the spectacle arch (4) from the model (6) is filled with a hardenable plastic material which sets on the spectacle material. Said plastic material forms after hardening on the spectacle arch (4) an additional layer (5) adapted to the back of the nose of the person wearing the spectacles.

Abstract: A seat for a vehicle, aircraft or the like includes a seat part and a backrest whereby the backrest is provided with an integrated headrest. In order that, on the one hand, the area of the cervical spinal column-lordosis of the respective seat user is effectively supported during the driving operation and, on the other, injuries of the cervical spinal column are at least reduced in case of an impact, a continuously changeable vacuum cushion is arranged at the backrest within the area of the headrest which is adapted to be individually matched to the cervical vertebrae column-lordosis of the respective seat user by means of an extraction pump and at least one valve.

Abstract: A system for generating a prescription wheelchair or other seating or body support arrangement includes a deformable seat portion. A patient to be fitted with the wheelchair is placed upon the seat deforming a surface thereof. A signal representative of force distribution resultant from the patient along the seat is generated. In accordance with this signal, the seat surface may be selectively varied by a plurality of pneumatic actuators. An updated force distribution signal is generated. In this fashion, a means and method is provided for arriving at preselected force distribution of the patient on the wheelchair seat. This data is made available for transmission to a fabrication unit from which a permanent seat cushion with the desired characteristics may be fabricated.

Abstract: A method and apparatus for manufacturing an otoplastic. An otoplastic is manufactured directly in the ear of a hearing-impaired person in that a deformable envelope is pulled over a die or over a shell or over an overlayed over-shell. This apparatus is then supplied with flowing otoplastic material between the die and the envelope, being supplied therewith in the ear. The envelope expands and assumes the shape of the auditory canal. After hardening or curing of the otoplastic material in the ear of the hearing-impaired person, the envelope and the die are removed and a module of either an in-the-ear or of a behind-the-ear hearing aid is integrated therewith.

Abstract: An ionogenic compound, soluble or dispersible in aziridine compounds is utilized for delaying the polymerization of aziridine compounds initiated by a sulfonium salt. Said ionogenic compounds contain an anion which is more nucleophilic than the anion present in the sulfonium salt employed. Moreover, a preparation for dental purposes is described which contains these components.

Abstract: A dental impression composition comprising alginate material and biocidal component.A method for reducing microorganism contamination in alginate dental impressions comprising preparing a mixture comprising alginate, water and biocide.

Abstract: On the basis of a hollow die including over-shell and a cap drawn onto a proximal connector of the die, an ear impression is produced directly in the auditory canal that is filled with ear impression material. Displaced ear impression material thereby flows through a channel in the cap into the hollow interior of the die. A negative is produced from the ear impression together with a screwed-on fixing star, this negative containing impressions of the points of the fixing star. After injection of otoplastic material and repositioning of a fixing star with a die, over-shell and cap into the fixing depressions, a finished otoplastic shell can then be produced from the negative.

Abstract: The combination of a die simulating the outside contour of an in-the-ear hearing aid module with an over-shell end cap which is seated on a die connector or neck projecting through a proximal hole of the over-shell is immersed into fluid otoplastic shell material which is situated in the negative of an ear impression. The hardened blank is proximally and distally freed of otoplastic shell material and is also proximally freed from the cap such that the die or a remaining part of the die can be easily and unproblematically removed in distal direction, so that the over-shell with the otoplastic shell material seated thereon remains as a finished otoplastic shell.

Abstract: An orthotic support system is embodied as cooperating seat and back cushion elements for assembly into a wheelchair frame. These cushion elements are custom-fitted to the individual patient by injecting an incipiently reacting and foaming, fluorocarbon-blown polyurethane chemical system into the space between a rigid mold box and an elastic membrane which is fitted over the open face of the mold box and which is deformably engaged by the appropriate portions of the patient's torso. The foaming mixture is injected in predetermined excess volume and expands against the physical resistance of the patient's body where contact is made with the corresponding regions of the elastic membrane; and this forcible engagement produces selective densification of the foam where a high degree of body support is required. Elsewhere, the foam expands more freely and stretchably inflates the membrane to generate graduatedly less dense regions matably contoured to fit or partially embrace the patient.

Abstract: The invention relates to a process for manufacturing an in-the-ear-canal hearing aid with microphone, amplifier, volume control, battery compartment with battery, and earphone, together with an individually matched ear-piece by making an impression of the ear canal for producing a casting mold and filling the casting mold with a polymerizable plastic.The new process involves pulling at least one prefabricated plastic hollow body, matched to the dimensions of the earphone and the other components, into the casting mold, filling the cavity between the hollow body and casting mold with polymeriable plastic, polymerizing the plastic and completing the hearing aid by inserting the earphone and the other components into the completed ear-piece, including securing a cover plate to the ear-piece, after stripping and removal of all parts not required.

Abstract: Hand grips for applying to motorcycles, bicycles, tools, golf clubs, fishing rods, guns, crutches and the like can be custom molded to fit exactly to the contours of the user's hand. The grip is put in place and then heated with a hair dryer. The user grasps the hot grip and then releases it. The hot grip conforms or molds to the shape of the user's hand and retains that conformation upon cooling. The grip may incorporate special surface properties for comfort and adhesive and resilient inner layers for enhanced function.

Abstract: An inner conical recess fitting (1) which is connectable to the prosthesis and is intended for receiving a stump (17) of an amputated extremity can be fitted directly to the stump (17) without the aid of modeling in the following procedural steps: to mold the inner conical recess, a plastic which is shrinkable through the action of external influences, such as heat, is selected; a tube (14) which is made of this plastic and is open at at least one end and has a smaller diameter and a smaller length than the inner conical recess fitting (1) to be manufactured is extended and stretched, so that it has in every direction a greater dimension than the inner conical recess fitting (1) to be manufactured; and the widened and stretched molded piece (10) is placed on the stump (17) and is made to shrink through, e.g., application of heat at selected locations, until the fitting bears everywhere securely against the stump.

Abstract: This invention relates to an article of manufacture and a method for making same, such as an artificial bird body used in taxidermy and essentially made to represent a plucked bird body using a polyurethane foam casting of the plucked carcass. The final foam casting is made in a two (2) step process. The first step consists of plucking the feathers from a bird so that the skin, muscles, connecting tissue and bones are intact in the bird body. Next, a casting is made using a specific procedure so that the bird is cast in the final pose desired. Special slots are made to insert the tibia and the tail portions of the bird. An additional provision is made for the insertion of a heavy wire for giving structural strength to the bird body and for mounting the neck and/or head of the bird. A second casting is then made of the reconfigured first casting and the second casting used for the final product.

Abstract: A process for making a moldable article for individualizing the operative surfaces of implements such as the hand grip of tennis racquets or hand tools. The moldable article is a sheet of polymeric material, including a polyurethane or thermoplastic-rubber copolymer component blended with volatile solvents and fillers to form a moldable mass that after receiving an individual's hand impression, for example, cures by solvent evaporation at ambient temperatures to a solid non-tacky hand grip. The moldable article is made by mixing the components together and forming a sheet which is sandwiched between semipermeable films that permit partial evaporation of the solvents. The sheet is then packaged between non-permeable films which prevent further evaporation until impressed by the consumer and exposed to air drying.

Abstract: Accurate heads are prepared by molding processes for the use by taxidermists in preparing fish for permanent display. The heads are removed from the silicone rubber mold just after the molding composition has achieved its peak exotherm and becomes very firm.

Abstract: A hearing aid including a plug that is tailored to snugly fit into the auditory canal of the user's ear, and that has a preshaped component assembly embedded therein, the component assembly comprising shell-like members that are interconnected to each other and that have the electrical components of the hearing aid mounted therein, the members being prearranged to achieve a configuration generally similar to the shape of the plug and being secured in end-to-end position for mounting interiorly in a negative impression in a mold as formed from the user's auditory canal, the assembled members being embedded in the negative impression in the mold upon pouring of a quick setting plastic material into the negative impression, thereby permanently fixing the preshaped assembly in the plug that is formed as the quick setting plastic material hardens around the assembled preshaped members.

Abstract: A taxidermic specimen and a method of formation thereof is disclosed. A preliminary negative mold (28) is formed by applying an alginate material to the jaw structure of the animal carcass. Fibers (50) are disposed within the depressions (30, 32 and 34) to provide tooth stains. Tooth-colored acrylic material is alternately poured in layers into the teeth depressions (30, 32 and 34) of the preliminary mold (28). The hardened acrylic teeth (44, 46, 48) are removed and chamfered around the gingival line (40). The teeth are reinserted into the preliminary mold (28) and covered by palate and gum forming fiberglass. Natural appearing colorations are provided comprising selected colored threads (52) near the surface of the gum structure. The composite tooth, gum and palate structure forms the master mold (54). From the master mold (54) a final rubber production mold is formed which is used to construct additional production taxidermic specimens in the same manner in which the master mold (54) was formed.

Abstract: Disclosed is a method of fabricating a prosthetic member (112) having personalized features of the patient, and being formed to provide an individualized fit to the patient's extremity (18). A rigid jacket (30, 32) is first formed around the uninsured foot (10) and the amputated extremity (18). The limb characteristics are impressed into an alginate (44) lining within the jackets (30, 32). A stone material poured into the alginate lining (44) forms stone models (48, 50) of the patient's limbs. A wax preliminary model (64) is scuplted in the likeness of the stone foot model (48) and used to form final stone mold halves (100, 102). The contour of the stone extremity model (50) is adjusted according to the tissue texture of the patient to provide an individualized fit. A gelatinous silicone is injected inside the final mold (100, 102) and allowed to form around the extremity model (50) to thereby provide the body of the prosthetic member (112) and the conformal sleeve (132 ).

Abstract: An apparatus for obtaining a pressure tight seal around the ostium of a blood vessel branch by clamping to the parent blood vessel or duct wall without deforming the branch. The apparatus may then be used for the injection of a hardenable material such as a polymerizable liquid plastic or a hardenable radiopaque liquid. When the blood vessel or duct is completely filled and the injected material has hardened, the original blood vessel or duct tissue can be removed by corrosion. An accurate replica of the blood vessel or duct is then obtained. The replica may be studied as part of a postmortem examination or used for instruction. If the radiopaque liquid has been used, the replica may be studied by the use of x-rays.

Abstract: An implement handle is made for use by a crippled person, utilizing a cap adapted to receive an end of the implement and an initially flexible bag attached to the cap. Material in the plastic state is inserted into the bag, the material becoming rigid with the passage of time, and the bag is placed into the hand of the crippled person while the material is becoming rigid. The crippled person maintain a substantially constant grip on the bag during this process, whereupon the rigidified handle conforms itself to his particular grip.

Abstract: The process for fabricating a reusable artifical fingernail which enjoys a tight tolerance complimental fit with the natural nail substrate as a result of the method of fabrication. The process may involve the use of, (A) the natural nail [Direct Technique], of (B) a model of the natural [Indirect Technique] as a substrate in conjunction in each case with a secondary substrate forming an extension of the nail, and digit to accept in a continuous fashion a release agent and a coating of a curable material forming an artifical nail curing the acrylic material, preferrably by blue light source in the visible spectrum. The preferable material is an acrylic and removing the artifical nail so created, trimming flash and shaping it to the desired final configuration and reapplying with a non-permanent adhesive material.

Abstract: A hearing aid device for processing sound, which comprises a device for transducing sound to an electrical signal, a device for processing the electrical signal, a device for powering and regulating the processing device, and a device for transducing the processed electrical signal into sound, all these devices being enclosed in a case adapted for being inserted in an ear canal, an elastic layer defining a chamber on the outside of the case, the chamber containing a cold-curing composition consisting of at least two components, at least one partitioning wall within the chamber for separating the components from one another, the partitioning wall being adapted to be ruptured by being subjected to a pressure effect, the components being adapted, when being combined upon rupture of said wall, to provide a composition which expands during an initial curing period, and then sets rigidly with a substantial form stability.

Abstract: A cranium is firstly produced form an epoxy resin, whose thickness is adapted so that the compressive strength at a given point is the same as at the corresponding point of a real cranium. This is followed by the fitting of the soft parts, i.e. the brain, eyeballs, flats of the ear and nasal pyramid. These members are made from a silicone to which a variable quantity of oil has been added to ensure that their hardness is the same as that of the corresponding real organs. The cranium is then placed on a support permitting the correct orientation thereof in the mould where the skin is cast.

Abstract: A prosthesis adapted to be formed and reformed to a model made of a person's body part, and comprised of a blank member of cured vinyl plastic or the like prepared for formation and reformation and to be softened to a plastic condition at raised temperature substantially below its previous curing temperature and brought into conformity with the model countours and permitted to return to room temperature for hardening, and thereafter stripped from the model for use.

Abstract: Sport fishing rods such as whip rods, cast rods having a good grip adapted to each user for more efficiency and improved comfort. The process of the "do it yourself" type is comprised of a set of 5 components which are differentiated by separate bags, and which amalgamate according to a predetermined method of using and being adjusted by moulding prints on the original handle. The process may also be applied to other instruments such as shooting guns, bows, handles for ski sticks, and all personal objects requiring a cold moulding.

Abstract: In a method of manufacturing a prosthesis cuff to receive an amputation stump, particularly for a lower-leg prosthesis, a positive cast of the stump is positioned in an expanded and heat shrinkable rough cuff of a plastics material, whereupon the rough cuff is caused by heating and vacuum-forming to adjust to the surface contour of the stump. The positive cast is subsequently removed. A connecting element for the prosthesis is provided on the rough cuff, for example having formation embedded in the plastics material.

Abstract: The thermoformable element comprises a strip (1) formed from two layers of foam (2, 3) of a thermoplastic polymer. The layers are welded to one another along their longitudinal edges so as to form a space between them in the shape of a channel (4). The inlet for the channel can be controlled by a non-return valve (6) whereas the exit can comprise a plug (7). The element is thermoformed by circulating a fluid heated to 130.degree. to 140.degree. C. through the channel until the foam becomes soft.

Abstract: An acoustic monitoring device for sound sensing in the recording, reproduction, broadcasting, or transmission of sounds, and a process for forming the device. The acoustic monitoring device is shaped like a human head equipped with anatomical features which accurately reproduce the shape of the auricles, the auditory meatus, the Eustachian tubes, and the nasal and oral cavities. Membranes responsive to sound pressures are located at the positions of the ear drums or other auditory organs. The device is produced by a process that includes forming a first mold on a human head, forming a casting from that mold, forming a second mold on the casting, and painting the second mold with a liquid silicone rubber which is allowed to dry to form resilient casting segments simulating the human head. Anatomical features simulating the brain and internal members defining the Eustachian tubes and the nasal and oral cavities are provided within a skull model.

Abstract: A stimulator for penile erection comprises a body member which may be inserted into the rectum of a user, the body member being so shaped as to closely conform to the topological configuration of the rectum from the anal area to a site adjacent to the prostate gland. Within the body member is electrical circuitry for generating a neutrally stimulating electrical signal. Electrodes, placed at particular locations on the surface of the body member, apply the signal to the user. At least one of the electrodes closely contacts the prostate gland when the body member is operatively disposed, at a region or spot on the prostate gland previously determined to be sensitive to electrical stimulation.

Abstract: Prosthetic devices of utilitarian, yet natural and unprecedented life-like appearance, are formed of durable elastomers. A seamless flexible negative mold of a biological body member selected to form the basic model is made by painting on to it nylon mesh-reinforced silicone with direct monitoring and correction of the positioning of the parts. A positive wax model is cast in the mold and subsequently modified by sculpturing to the requirements of the individual for whom the prosthesis is being developed. From the master wax model a negative metal mold is made by electroplating. New and unique provisions for ventilation to effectively remove from the molds solvents of the elastomer dispersions greatly improve the quality and rapidity of production. Invented methods of creating ventilation ports without damage to the critical interior surface of the molds and of degassing the dispersions to eliminate bubble defects are employed.

Abstract: A hollow shell-type hearing aid is prepared from an impression of the ear. A mold is formed from the impression. An opening is cut in the mold and the mold is filled through the opening with hardenable material. The hardenable material is allowed to cure until a hard shell of the material forms on the surface of the mold. The remaining hardenable material is poured out of the mold through the opening and the shell is then removed.

Abstract: Apparatus for fabricating a compensating filter for use in radiation therapy includes a stylus for tracing the profile of a surface portion of a patient and a cutter for cutting a form. The stylus and cutter are positioned on first and second guides which are connected by a tie bar. A plurality of linkages translate movement of the stylus along its guide to the cutter along its guide. A mold is cut in the form which is filled with compensating material for forming the filter. The ratio of movement of the stylus to the cutter is established by the linkages in accordance with the ratio of radiation absorption of the compensating material to the radiation absorption of human tissue.

Abstract: The base (11) of a template forming device (10) has a planar, upper surface (12) onto which a plurality of orthogonal grooves (14 and 15) are recessed. A foam mixture is introduced into a container means (20) received on the base (11), and a plurality of restraining means in the form of slats (18) are insertably received within selected grooves (14 and 15) to confine the foaming action within the container means (20) and to direct it against a selected portion of the anatomy so that when the foam is fully risen and cured a template (40) is provided which can be repeatedly used accurately to reposition and support that portion of the patient's anatomy.

Abstract: A mold for stereotaxic injections into mouse striatum is disclosed which includes upper and lower mold halves defining therebetween a shaped interior cavity closely conforming to shape of the mouse head. Indentations are provided in the shaped cavity of the lower mold half to receive and retain therein the mouse upper incisors to longitudinally establish and set the position of the mouse head in the mold. A plurality of dowel pins project upwardly from the lower mold half and insert respectively into vertically registered, parallel, pin receiving openings provided in the upper mold half. One or more needle guide cannulae are secured in the upper mold half in precise alignment with a preselected nucleus area to receive and guide therethrough a skull piercing needle and secondly the needle of a micro-liter syringe.

Abstract: A hearing aid including a plug that is tailored to snugly fit into the auditory canal of the user's ear, and that has a preshaped component assembly embedded therein, the component assembly comprising shell-like members that are interconnected to each other and that have the electrical components of the hearing aid mounted therein, the members being prearranged to achieve a configuration generally similar to the shape of the plug and being secured in end-to-end position for mounting interiorly in a negative impression in a mold as formed from the user's auditory canal, the assembled members being embedded in the negative impression in the mold upon pouring of a quick setting plastic material into the negative impression, thereby permanently fixing the preshaped assembly in the plug that is formed as the quick setting plastic material hardens around the assembled preshaped members.

Abstract: An improved method for making custom molded seat cushions wherein a bead-filled latex bag is used as a trail buttocks supporting cushion and likewise another bead-filled latex bag is used as back-supporting cushion in a frame which is similar in function to the seat frame of the chair. An impression of a desired portion of a user's body is formed on each of the bags and air is removed from the bags thereafter to fix the impression. A positive mold of the individual's respective backside and buttocks impression are made. Corrective changes may be made either to the latex bag impression as it is being formed or the positive mold impression. The positive mold impression is then utilized along with a mold frame to mold a custom fitted seat cushion for the individual who will utilize the wheelchair.

Abstract: A method for producing an external breast prosthesis or support by forming a mold directly from the subject for whom the prosthesis is being prepared. After a molding material is applied to the subject's breast, the breast is immersed in an isodensity liquid to present the breast to a zero-gravity condition while the molding material cures.

Abstract: An impact dissipator for the protection of bones and organs of the human body from impacts or falls. The dissipator is bell-shaped and has an outer layer which consists of an elastic rubber substance. Within the shell-like outer layer a viscous fluid layer is located, which is bonded thereto, with the fluid layer forming a skin-friendly adhesive layer adapted to contact and conform to the area being protected.

Abstract: An improved process for making a vent for an "in the ear" hearing aid. A cavity is formed which corresponds to the structure of the ear canal and outer ear of the hearing aid user. A molding liquid, such as acrylic, is poured into the cavity. The liquid is allowed to partially cure and form a thin-walled shell inside the cavity. An elongated mandrel is then placed along the inside of the thin-walled shell, and additional liquid molding material is poured into the thin-walled shell around the elongated mandrel. The wall of the shell accordingly becomes thicker, enveloping the mandrel. The mandrel may then be removed, leaving the vent in the wall of the shell.

Abstract: A method of making a dental prosthesis includes providing an upper or a lower impression of the oral cavity of a patient; and filling such impression with a castable mixture comprising (1) a ceramic composition containing a major proportion of magnesia and a significant minor proportion of alumina and (2) an aqueous composition containing silica as the essential ingredient, the ratio of the aqueous silica composition to the ceramic composition being such as to render the latter flowable. The mixture is then permitted to harden in the impression, and the resulting hardened model is removed from the impression. Thereafter, a liquefied metal composition is spray-coated on to a selected portion of the model to form a metallic prosthetic base, which is separated from the selected portion of the model and provided with a porcelain coating on its exterior surface.

Abstract: A hearing aid including a plug that is tailored to snugly fit into the auditory canal of the user's ear, and that has a preshaped component assembly embedded therein, the component assembly comprising shell-like members that are interconnected to each other and that have the electrical components of the hearing aid mounted therein, the members being prearranged to achieve a configuration generally similar to the shape of the plug and being secured in end-to-end position for mounting interiorly in a negative impression in a mold as formed from the user's auditory canal, the assembled members being embedded in the negative impression in the mold upon pouring of a quick setting plastic material into the negative impression, thereby permanently fixing the preshaped assembly in the plug that is formed as the quick setting plastic material hardens around the assembled preshaped members.