Abstract: Micaceous glass-ceramics are useful in the fabrication of single and multi-unit dental restorations including but not limited to orthodontic appliances, bridges, space maintainers, tooth replacement appliances, splints, crowns, partial crowns, dentures, posts, teeth, jackets, inlays, onlays, facing, veneers, facets, implants, abutments, cylinders, and connectors by machining the glass-ceramic using CAM/CAM devices. The micaceous glass-ceramics are provided in a plurality of shades and colors to adequately match the colors and shades of teeth found in 95% or more of the human population.

Abstract: Refractory investment material and method for forming a positive replication of a tooth structure on which a high-alumina based porcelain tooth restoration is to be formed, the material being formed from a refractory powder which includes calcined alumina mixed with a liquid carrier comprising an aqueous colloidal dispersion of silicon dioxide. The method comprises the steps of: preparing a negative impression of the tooth structure on which a tooth restoration is to be placed; forming a positive replication of the tooth structure by pouring the mixture of refractory powder and aqueous dispersion into the negative impression; allowing the positive replication to harden; removing the positive replication from the negative impression for degassing and cooling; and coating the positive replication with a mixture of high-alumina porcelain in an aqueous carrier to form a core layer of porcelain on which subsequent layers of high-alumina porcelain may be applied.

Abstract: Solid free form fabrication techniques such as fused deposition modeling and three-dimensional printing are used to create a dental restoration. Three-dimensional printing comprises inkjet printing a binder into selected areas of sequentially deposited layers of powder. Each layer is created by spreading a thin layer of powder over the surface of a powder bed. Instructions for each layer may be derived directly from a CAD representation of the restoration. The area to be printed is obtained by computing the area of intersection between the desired plane and the CAD representation of the object. All the layers required for an aesthetically sound restoration can be deposited concurrently slice after slice and sintered/cured simultaneously. The amount of green body oversize is equivalent to the amount of shrinkage which occurs during sintering or curing.

Abstract: A method for manufacturing a metallic dental crown comprising making a model base out of a base formed on a tooth root in an oral cavity; capping only a top portion of the model base with a mold material for forming a dental crown occlusal portion which is made of plastic film and which has a shallow royal crown configuration; coating that area of an outer peripheral surface of the model base, which is not capped with the mold material for forming the dental crown occlusal portion, with wax to form a composite mold material for forming the dental crown integral with the mold material for forming the dental crown occlusal portion; and substitution molding the composite mold material for forming the dental crown with a metal material. A mold material for forming a dental crown occlusal portion used for manufacturing a metallic dental crown is also disclosed.

Abstract: A prosthodontic assembly comprises a restoration having a cavity defined by a first surface and an abutment positioned within the cavity. The assembly further comprises a plurality of standoffs positioned in between the first surface and the abutment to provide a gap. Methods for forming the restoration are also disclosed.

Abstract: A process for manufacturing an apatite ceramic, especially for biological use involves the preparation of a homogeneous mixture of powders to form a hydroxyapatite of formula Ca10(PO4)6(OH)2, stoichiometric or non-stoichiometric, possibly containing other additives or flaws, compacting the mixture under a pressure of 100 to 500 Mpa at room temperature, and subjecting it to hydrothermal treatment at low temperature (100 to 500° C.) in the presence of water and in a sealed chamber.

Abstract: The invention provides a curable system and method of making a dental prosthesis. The method of making a dental prosthesis includes providing a one component denture base resin composition which is polymerizable by microwave energy. The one component denture base resin composition is injected into a mold enclosed by a flask having a body wall which is substantially transparent to the microwave energy. The curable system includes microwave energy sensitive initiators and polymerizables (meth)acrylate Monomers having molecular weights preferably between 400 and 20,000. The initiators are adapted to initiate polymerization of the polymerizable Monomers by application of microwave energy to the flask. The initiators are adapted to remain stable and not initiate polymerization of the Monomers for at least one year at 23° C. in the absence of microwave energy.

Abstract: A container for cross-linking composite materials on dental bridges and arches and on individual teeth, comprising: a plurality of plate-like elements which can be stacked and clamped together, at least one of the plate-like elements, which is internal to the plurality of plate-like elements, being constituted by a plurality of blocks which can be removed independently of each other to form an area which is suitable to constitute a mold into which it is possible to place a metallic structure on which the elements of a dental prosthesis are to be formed, the at least one of the plate-like elements and a plate-like element that is adjacent thereto in an upward region and constitutes the top plate-like element of the container being both made of a material which is transparent to light.

Abstract: Solid free form fabrication techniques such as fused deposition modeling and three-dimensional printing are used to create a dental restoration. Three-dimensional printing includes ink-jet printing a binder into selected areas of sequentially deposited layers of powder. Each layer is created by spreading a thin layer of powder over the surface of a powder bed. Instructions for each layer may be derived directly from a CAD representation of the restoration. The area to be printed is obtained by computing the area of intersection between the desired plane and the CAD representation of the object. All the layers required for an aesthetically sound restoration can be deposited concurrently slice after slice and sintered/cured simultaneously. The amount of green body oversize is equivalent to the amount of shrinkage which occurs during sintering or curing.

Abstract: A method of controlling an oven for producing tooth replacement components. An electric motor moves a piston that acts upon a moldable restoration material. The restoration material is introduced into a muffle oven having an oven hood that can be removed from the muffle. The compactibility curve is established as a function of the type of dental material utilized. Immediately after conclusion of the mold time, the motor is turned off and the oven hood is removed.

Abstract: A method for manufacturing a fiber rein-forced composite dental restoration comprising the steps of (i) preparing a mould; (ii) filling the cavity of the mould with a fiber-reinforced polymerizable material comprising an organic matrix and a fiber component embedded within the matrix; (iii) applying pressure to the fiber-reinforced polymerizable material; and (iv) curing the fiber-reinforced polymerizable material. The method is characterized in that the mould is designed in a way which allows excess organic matrix material to escape form the cavity during pressing.

Abstract: The invention relates to a method for manufacturing a fiber reinforced composite comprising the steps of (i) preparing a mould; (ii) filling the cavity of the mould with a fiber-reinforced polymerizable material comprising an organic matrix and a fiber component embedded within the matrix; (iii) applying pressure to the fiber-reinforced polymerizable material; and (iv) curing the fiber-reinforced polymerizable material. The method is characterized in that the mould is designed in a way which allows excess organic matrix material to escape form the cavity during pressing.

Abstract: The invention proposes a supporting device for the manufacture of dental prosthetic components in the field of dental implants and, more specifically, of connecting elements, which provide a faster, cheaper and dependable technique, and which helps the dentist in his task with the objective of eliminating addition or subtraction operations when using said connection elements. This objective is attained, in accordance with the invention, for the supporting device includes a support component (10) having an orifice (80) with an internal thread and a screw element with an external thread, which mutually engage to constitute a safe support for a machined odontological block to be formatted.

Abstract: A pressure molding apparatus comprises a furnace defining a heating space for accommodating a mold assembly including a mold body charged with a raw material to be molded, and a pressure piston for pressurizing the raw material; heating means for heating the heating space; and load imposing means for imposing a load on the pressure piston to mold the raw material. The load imposing means includes at least one weight means and weight supporting means. The weight supporting means is selectively set in a load-free state in which the weight supporting means supports the weight means so that the weight of the weight means is not imposed on the pressure piston, and a load imposed state in which the weight supporting means releases the support of the weight means so that the weight of the weight means is imposed on the pressure piston.

Abstract: The invention includes a system and method for making injection molded dental appliance apparatuses having an injector module removably attached to a dental flask, a press and a controlled compression apparatus, wherein the press and compression apparatus introduce pressure into the dental flask and the injector module, which pressure may or may not be maintained during curing of the appliance. The invention also includes a system for dispensing dental appliance chemicals having at least one chemical dispensing apparatus and a mixing container; whereby a separate dispensing apparatus is used for each chemical and the chemicals are dispensed and mixed in the same container.

Abstract: A process for producing a ceramic network material including the steps of: introducing a ceramic powder into a mold to form a molded material; firing the molded material to form a ceramic, open pore network; infusing the ceramic network with a silane solution; infusing a monomer to at least a portion of the ceramic network; and forming an interpenetrating network. The ceramic network materials may be used as restorative materials and in various devices such as posts, implant abutments, orthodontic brackets and blocks.

Abstract: A retroreflective article has first and second segments each comprising a binder layer and a multitude of microspheres partially embedded in the front surface of the binder layer. The first segment also has an opaque reflective metal layer disposed on the embedded portions of the microspheres; whereas, the second segment lacks such an opaque reflective metal layer and thereby allows the color of the underlying binder layer to be seen from the front side of the retroreflective article. The first and second segments display noticeably different colors under daytime lighting conditions, and each possesses a distinctly different retroreflective efficiency when viewed under retroreflective lighting conditions. The first and second segments therefore stand out in contrast to each other to enhance the conspicuity of the retroreflective article.

Abstract: In a method of producing a lightguide plate for surface light source according to the present invention, a plate-shaped metal mold for defining the shape of a part of a cavity of a molding die and particularly, the shape of a light emitting surface of the lightguide plate for surface light source (a concavo-convex shape, a lenticular lens shape, etc.) is provided so as to be replaceable, to form a cavity having a desired shape by the replacement of the plate-shaped metal mold. Resin liquid is injected into the cavity, its resin liquid is solidified, and the resin is then released from the cavity. Consequently, a lightguide plate for surface light source having a desired shape and particularly, having its light emitting surface in a desired shape is produced.

Abstract: A shaped, high-strength dental ceramic prothesis is made by pressing a molding composition comprising about 1-50 wt % glass particles and about 50-99 wt % ceramic particles to form a ceramic frame, veneering the frame and firing the coated frame.

Abstract: Laminae suitable for use in a mold suitable for use in forming retroreflective sheeting and methods of making such laminae are disclosed. A representative lamina includes a single row of optically opposing cube corner elements disposed on its working surface. The working surface of a lamina is provided with a plurality of cube corner elements formed by the optical surfaces defined by three groove sets. Corresponding surfaces of opposing groove sets intersect substantially orthogonally along a reference edge to define first and second optical surfaces of the respective cube corner elements. The third optical surface of each respective cube corner element is defined by one surface of the third groove set.

Abstract: A microprism master mold is formed from a plurality of flat sheets having two mutually parallel major surfaces. On one edge thereof, there is provided a series of V-shaped grooves having a bottom angle of about 90.degree. and roof-shaped projections having a vertical angle of about 90.degree., successively formed at a fixed repeating pitch and in a direction perpendicular to the major surfaces. The flat sheets are stacked so that the vertices of the roof-shaped projections formed on each flat sheet meet the bottoms of the V-shaped grooves formed on an adjacent flat sheet. The microprism master mold includes two or more different types of roof-shaped projections and the thickness of each flat sheet is equal to 0.6-2.0 times the length of the shorter oblique sides of the roof-shaped projections. The master mold is useful for production of cube-corner type retroreflectors characterized by microprism having high brightness and excellent wide-angle properties.

Abstract: A continuous process for producing printed patterns on retroreflective material is disclosed, wherein a partially cured pattern is printed on a roll of film and partially cured cube-corner prisms are bonded to the film over the printed matter thereby encapsulating the printed matter to protect the printed matter from the environment.

Abstract: A continuous process for producing printed patterns on retroreflective material is disclosed, wherein a partially cured pattern is printed on a roll of film and partially cured cube-corner prisms are bonded to the film over the printed matter thereby encapsulating the printed matter to protect the printed matter from the environment.

Abstract: A durable colored article having fluorescent properties comprises a substantially solventless polyvinyl chloride matrix, a thioxanthene fluorescent dye, and a secondary or tertiary hindered amine light stabilizer having a molecular weight less than about 1000 grams/mole. The invention has the advantage in that it provides a flexible polyvinyl chloride film that exhibits durable fluorescent colors.

Abstract: A method for producing a dental prosthesis to be fitted to a fitting member including the steps of: determining the three-dimensional contours of the fitting member; producing a three-dimensional form of the dental prosthesis; producing a working stump and/or a working pack; placing the working stump in the form and/or packing the working pack around the outside of the form to completely cover the form; sintering the form with the working stump and/or the working pack; and separating the working stump and/or the working pack from the dental prosthesis after sintering. The working stump and working pack are produced such that they are enlarged by a predetermined enlargement factor.

Abstract: A method of machining a substrate to produce a cube corner element optical array. The method includes steps of directly machining a plurality of groove sets into a directly machinable substrate to form an array having a plurality of geometric structures including cube corner elements, and machining at least two of the groove sets along the same path in the substrate but at different depths of groove to produce a geometric structure side surface having both an optical portion and a non-optical portion.

Abstract: Shaped article replicas which are proportionately accurate replicas of a shaped article and which are equal, greater or smaller in size than said shaped article are made by preparing a swellable polymer replica of said shaped article; immersing said swellable polymer replica in a swelling agent system under conditions which will enlarge said polymer replica to a predetermined extent; forming a casting mold of such enlarged polymer replica; making a powder compact in said casting mold and heating said powder compact to produced a proportionately accurate solid replica of a predetermined size.

Abstract: A method and apparatus for producing a lenticular plastic sheet from a plastic sheet having a first surface and an opposite second surface employs a first chill roller having an outer surface, a patterned chill roller having an outer surface defining a first lenticular pattern thereon, disposed adjacent and parallel to the first chill roller so as to define a first nip therebetween and a second chill roller, having an outer surface and being spaced apart from the first chill roller and disposed adjacent and parallel to the patterned chill roller so as to form a second nip therebetween. A plastic sheet is extruded into the first nip so that the plastic sheet is molten as it passes into the first nip and so that the first surface of the plastic sheet is in contact with the first lenticular pattern, thereby facilitating the formation of a second lenticular pattern on the first surface. The second lenticular pattern is complimentary in shape to the first lenticular pattern.

Abstract: A method for infrared bonding a transparent plastic article having a first surface and a transparent bonding surface to an opaque plastic article having an opaque bonding surface. The method includes the following steps: The transparent article is aligned with the opaque article. The transparent bonding surface is juxtaposed the opaque bonding surface. An infrared beam is directed through the transparent article. The infrared beam is focused on the opaque bonding surface and causes the opaque bonding surface to heat and soften. The transparent article is contacted with the opaque article. The transparent and opaque bonding surfaces are urged together. The transparent and opaque bonding surfaces are fuse together.

Abstract: An optical memory device and a method for manufacturing thereof. An optical memory device has at least one data layer formed on a substrate. An upper surface of the substrate is formed with a pattern comprising a plurality of regions which are capable of obtaining, when covered by a recording medium, desired optical properties different from those of the substrate. The patterned surface of the substrate is coated with the recording medium. The recording medium is removed from the patterned surface after the recording regions have obtained the desired optical properties.

Abstract: A reflection screen includes a light-reflecting substrate laminated with a light-transmitting polymer layer having light absorptive crazes of regular directionality. The reflection screen is formed by coating or laminating the light-reflecting layer on the substrate, drawing over a blade in a direction perpendicular to the blade to form the crazes and inserting a light-absorbing material into the crazes. Images projected on the reflection screen have high contrast and can be observed as sharp images even in a lighted area such as in a room lighted by fluorescent lighting.

Abstract: A solar insolation concentrator fabricated from a rigid lightweight (slab-like substrate and a plurality of reflectors. Inclined surfaces are formed in the face surface of the substrate, such as by impressing a heated plate portion of a fabrication tool into the substrate material. The fabrication tool is then used to position the reflectors as they are adhered to the inclined surfaces to assure that the reflectors are aligned with respect to a common focal point. An embodiment of the solar insolation concentrator comprising a plurality of identical square flat back-silvered glass mirrors mounted within recesses within a block of high density cellular polystyrene and a tool and process used to fabricate this concentrator are disclosed. The solar insolation concentrator is also suited for use as a reflector of electromagnetic radiation having wavelengths outside the solar energy spectrum.

Abstract: Self-metallizing, flexible polyimide films with highly reflective surfaces are prepared by an in situ self-metallization procedure involving thermally initiated reduction of polymer-soluble silver(I) complexes. Polyamic acid solutions are doped with silver(I) acetate and solubilizing agents. Thermally curing the silver(I)-doped resins leads to flexible, metallized films which have reflectivities as high as 100%, abrasion-resistant surfaces, thermal stability and, in some cases, electrical conductivity, rendering them useful for space applications.

Abstract: A laminate structure of a retroreflective film includes one layer of a prismatic plastic film laminated to a heat sealable, white polyester film having a pattern of aluminum deposited such that the resulting laminate is very cost effective to produce and has superior whiteness properties when compared to conventional films.

Abstract: This invention relates to a method of making a microprism master mold which is suitable for use in the production of cube-corner retroreflectors, especially in the form of thin retroreflective sheeting, and permits the formation of hexagonal prism type microprisms having both high reflectivity and excellent angularity. This method is characterized in that, in making a cube-corner microprism master mold by stacking a plurality of flat sheets having two mutually parallel major surfaces, cutting V-shaped grooves on one lateral surface of the resulting flat sheet stack in a direction perpendicular to the major surfaces and at a fixed pitch to form a series of successive roof-shaped projections having a vertical angle of about 90.degree., and then shifting the flat sheets so that the vertices of the roof-shaped projections formed on each flat sheet meet the bottoms of the V-shaped grooves formed on an adjacent flat sheet. The flat sheets having a thickness of 50 to 500 .mu.

Abstract: A back lighting device includes a light waveguide having generally planar upper and lower surfaces, a light module having a lamp member encapsulated between the upper and lower surfaces, a specular reflective material applied about the waveguide lower surface, and a light extracting material applied about the waveguide upper surface. The waveguide can be mounted in a user specific frame to allow high volume usage of a common waveguide element.

Abstract: An artificial tooth of plastic or ceramic material. The artificial tooth has a tooth body comprising an internal solid core (1) and at least one external layer (2) formed by injection molding and enveloping the solid core (1) at least in part.

Abstract: A retroreflective article 10 has a body portion 14 and a multitude of cube-corner elements 12 that project from a rear side 20 of the body portion 14. The body portion 14 includes a body layer 18 that contains a light-transmissible polymeric material having an elastic modulus less than 7.times.10.sup.8 pascals. The cube-corner elements 12 contain a light transmissible polymeric material having an elastic modulus greater than 16.times.10.sup.8 pascals. A retroreflective article of this construction can be highly flexed while maintaining good retroreflective performance.

Abstract: Laminae suitable for use in a mold suitable for use in forming retroreflective sheeting and methods of making such laminae are disclosed. A representative lamina includes a single row of optically opposing cube corner elements disposed on its working surface. The working surface of a lamina is provided with a plurality of cube corner elements formed by the optical surfaces defined by three groove sets. Corresponding surfaces of opposing groove sets intersect substantially orthogonally along a reference edge to define first and second optical surfaces of the respective cube corner elements. The third optical surface of each respective cube corner element is defined by one surface of the third groove set.

Abstract: A method for making multilayer optical films is provided in which the degradation of the optical extinction of the thinnest optical layers is avoided by casting these layers close to the casting wheel.

Abstract: A retroreflective article (10) has retroreflective elements (12) partially embedded in a binder layer (14) that contains a solid polyurethane. The polyurethane includes soft segments, hard segments, silicon moieties, and urethane moieties. The specific chemical identities and relative amounts of the segments and moieties are sufficient to impart desired high elongation and low modulus to the polymer. The inventive retroreflective article is capable of demonstrating extraordinary laundering durability under industrial wash conditions and tumble and tunnel drying.

Abstract: A ceramic powder having a uniform particle diameter of 50 .mu.m or smaller is used as a dental ceramic powder to produce a high-precision and compact artificial tooth. The ceramic powder fired assures a non-porous and compact structure of the artificial tooth. In a manufacturing method for the artificial tooth, the cream of ceramic powder is poured into a core, the core with the ceramic cream loaded is frozen to shape, thawed, dried and then fired in a furnace. To assure even more compact structure, the cream is compacted and hardened prior to freezing. Pressure is efficiently applied in the compaction and hardening process.

Abstract: A process is described for forming a lighting louver that includes a plurality of louver members. The process includes the steps of providing a sheet of thermoformable material and heating the sheet to a pliable state. A further step includes providing a forming mandrel having a series of mandrel partitions arranged with spaces between the partitions. The heated sheet is positioned over the forming mandrel, and is forced against the forming mandrel to form the heated sheet over the mandrel partitions and thereby produce a formed louver blank including formed louver segments that conform to the mandrel partitions and webbing segments that span the spaces between the partitions on the forming mandrel. In one preferred form the webbing segments are removed. In another preferred form, transparent webbing segments are formed that do not require removal and will transmit light. The webbing segments in the first form are removed from the louver blank to form light transmissive openings through the louver blank.

Abstract: Provided is a method for manufacturing a thermoplastic resin sheet bearing an embossed pattern, which employs a manufacturing apparatus having a first roll having an elastic material coated surface, a mirror-faced metal, endless belt, which is wound around the first roll and a second roll, and a third roll so provided that the metal, endless belt is wrapped partially around the third roll, which contacts the first roll via the metal, endless belt and which has an embossed pattern formed on one surface. According to this method, the thermoplastic resin sheet, partially melted, is fed between the metal, endless belt, which contacts the first roll, and the third roll. The elastic member is elastically deformed by application of a pressing force between the first and the third roll, while face pressure welding the thermoplastic sheet by using the first and the third rolls to transfer the embossed pattern and to cool the thermoplastic resin sheet. A surface temperature for the third roll of from 0.degree. C.

Abstract: This invention provides a method for continuously forming an array of optical elements which includes feeding synthetic resin sheeting having a temperature in the flow temperature region of the synthetic resin directly to a thermoforming zone of embossing means; continuously pressing the sheeting against a mold provided on the embossing means and having a pattern for defining an array of optical elements while maintaining the sheeting at that flow temperature, to bring the sheeting into intimate contact with the mold and thereby form an array of optical elements on one surface of the sheeting; laminating a surfacing film to the side of the sheeting opposite to the mold as required; feeding a carrier film to the side of the resulting laminate opposite to the mold and bringing the carrier film into close contact therewith; and cooling the sheeting to a temperature lower than the glass transition temperature of the synthetic resin, as well as apparatus therefor.

Abstract: A process for the production of coaxial and confocal mirrors having grazing incidence consists essentially of a support element or a carrier made of ceramic material, a layer reflecting X-rays and intermediate layer which is a buffer and which avoids the transfer of the rough surface of the carrier or support element to the reflecting layer. The support element or carrier is prepared by deposition involving the spraying of the ceramic material in the form of plasma (plasma spray deposition).

Abstract: A blank for preparing artificial tooth parts, such as inlays, overlays or partial and complete crowns and bridges comprises a body of laminate material. The body has at least one layer of high abrasive resistance, at least one layer of high breaking strength, and at least one layer of lower hardness and breaking strength. For forming the tooth part, material is removed from the blank in such a way that the layer having high fracture strength forms a reinforcing structure. In a single working step, a tooth part of high strength can be machined.

Abstract: A flexible, durable, cube-cornered retroreflective article capable of accommodating the expansion and contraction of the underlying polymeric substrate where such article has a pillowed or curved microstructured member bonded in a regular pattern to a sealing member. The retroreflective article has normal and stressed states. In the normal state, the microstructured member is substantially parallel with the sealing member. In the stressed state, the microstructured member is either compressed or elongated and the sealing member is substantially flat. The retroreflective article may be attached to traffic control devices, such as polymeric barrels, cones, or tubes to direct and guide motorists through road construction areas.

Abstract: Cellular retroreflective sheeting comprises a first film of thermoplastic material which has been formed to define arrays of minute cube-corner reflective elements on one face thereof. The reflective elements are covered with a second thin thermoplastic film and the two films together pass over a patterned roller where a series of sonic welding heads rapidly bond the films together forming small cells of retroreflective cube-corner elements in the pattern of the roller. Because the heat generated in the welding process is localized to the pattern of the roller, cell walls may be formed having narrow thickness yet good bonding of the films is achieved. Further, residual heat does not appreciably transfer to adjacent retroreflective elements, therefore, distortion of adjacent elements is minimized and a sheeting construction is achieved having superior brilliance and durability as well as maximum retroreflective capability over a wide angular range of incident light.

Abstract: A polymerization apparatus includes a support plate for supporting a workpiece to be polymerized and a hood comprising a light source for guiding light to the workpiece such that the light impinges on at least two sides of the workpiece. The hood is liftable relative to the support plate so as to allow access to the workpiece when in a lifted position. A heat source for heating the workpiece is provided. A control device controls the function of the polymerization apparatus. A method for operating the polymerization apparatus includes the steps of heating the workpiece to a desired temperature after switching on the light source, maintaining the desired temperature for a desired polymerization cycle time period, and subsequently shutting down the light source and the heat source for a final polymerization cycle time period.