Patents by Inventor Arun Prasad
Arun Prasad has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 6345984Abstract: Ready-to-use preshaped, prefabricated cured structural components are prepared in a variety of shapes and sizes to be used in the fabrication of dental appliances. Preferably the structural components are fabricated of a fiber-reinforced composite material or a particulate-filled composite material comprising fibers or particulate filler impregnated with a polymeric matrix. The polymeric matrix is partially or fully cured to the point of sufficient hardness to provide a ready-to-use structural component for use in the fabrication of dental appliances such as orthodontic retainers, bridges, space maintainers, tooth replacement appliances, splints, crowns, partial crowns, dentures, posts, teeth, jackets, inlays, onlays, facings, veneers, facets, implants, abutments, cylinders, and connectors.Type: GrantFiled: June 25, 1999Date of Patent: February 12, 2002Assignee: Jeneric/Pentron, Inc.Inventors: Ajit Karmaker, Martin L. Schulman, Arun Prasad
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Publication number: 20020009380Abstract: Dental restorations are fabricated using metal powder. Preferably, the metal powder is a high fusing metal and preferably, the metal powder comprises a non-oxidizing metal. The metal powder is applied to a die and is covered with a covering material such as a refractory die material preferably in the form of a flowable paste. A second covering material may be sprinkled or dusted onto the paste. The model is then dried prior to firing. After drying, the model is sintered to provide a high strength metal restoration. After sintering, the outer shell can be broken off easily with one's hand to expose the sintered coping.Type: ApplicationFiled: January 10, 2001Publication date: January 24, 2002Inventors: Gregg Daskalon, Arun Prasad, Denise L. North, Elie Zammarieh
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Publication number: 20020004018Abstract: Dental alloys are provided having a coefficient of thermal expansion in the range from about 8 to about 18×10 −6/° C. in the temperature range of 25-500° C. and melting temperatures above about 800° C. but below about 1500° C. The alloys contain gold in combination with a small amount of chromium and/or tantalum. Other elements may also be included with the gold and chromium and/or tantalum to provide the necessary forming, melting, and mechanical properties required to manufacture the desired dental restoration.Type: ApplicationFiled: January 26, 2001Publication date: January 10, 2002Inventors: Arun Prasad, Martin L. Schulman, Grant P. Day
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Patent number: 6325839Abstract: Metal materials are sintered using microwave energy to provide high strength dental restorations. The metal materials used to manufacture the dental restorations herein are sintered to high density to provide high strength products that have a density close to the density achieved when the same materials are cast. A dense solid having a fine microstructure is achieved using microwave heating. Through the process described herein, higher heating rates may be achieved, reducing the time necessary for sintering the materials. The process is faster than conventional processes used in the manufacture of dental restorations, eliminates time-consuming steps typically involved in the lost wax process and provides materials with better grain-size control and properties. It is possible to produce high strength dental restorations at lower temperatures having high hardness and density and small grain size.Type: GrantFiled: July 20, 2000Date of Patent: December 4, 2001Assignee: Jeneric/Pentron, Inc.Inventors: Arun Prasad, Gordon S. Cohen
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Publication number: 20010036617Abstract: Ready-to-use preshaped, prefabricated cured structural components are prepared in a variety of shapes and sizes to be used in the fabrication of dental appliances. Preferably the structural components are fabricated of a fiber-reinforced composite material or a particulate-filled composite material comprising fibers or particulate filler impregnated with a polymeric matrix. The polymeric matrix is partially or fully cured to the point of sufficient hardness to provide a ready-to-use structural component for use in the fabrication of dental appliances such as orthodontic retainers, bridges, space maintainers, tooth replacement appliances, splints, crowns, partial crowns, dentures, posts, teeth, jackets, inlays, onlays, facings, veneers, facets, implants, abutments, cylinders, and connectors.Type: ApplicationFiled: June 25, 1999Publication date: November 1, 2001Applicant: ANN M. KNABInventors: AJIT KARMAKER, MARTIN L. SCHULMAN, ARUN PRASAD
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Patent number: 6200136Abstract: The present invention relates to unique dental structures such as bridges and crowns. The bridge comprises a structural component such as a fiber reinforced polymeric base material impregnated bar disposed within interproximal cavities located in the distal occlusal surface of the mesial abutment tooth and the mesial occlusal surface of the distal abutment tooth, and a support element of woven fibers and polymeric base material. The support element can span the endentulous area, wrap around the structural component, and provide support for the veneer on the pontic.Type: GrantFiled: August 7, 1998Date of Patent: March 13, 2001Assignee: Jeneric/Pentron IncorporatedInventors: Arun Prasad, Ajit Karmaker, Elie Zammarieh
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Patent number: 6186791Abstract: A dental post comprising a rod fabricated of fiber-reinforced composite material. The rod comprises a plurality of frustoconical sections arranged coaxially along the longitudinal axis of the rod. Preferably the rod has consistent width along the longitudinal axis wherein the frustoconical sections each have the same tapered width and same length. The number of frustoconical units per rod can vary. The frustoconical sections may vary in shape. Moreover, the rod may include a channel therein extending along the longitudinal axis thereof. The rod may also include one or more grooves extending along the surface thereof.Type: GrantFiled: March 29, 1999Date of Patent: February 13, 2001Assignee: Jeneric/Pentron IncorporatedInventors: Ajit Karmaker, Arun Prasad
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Patent number: 6186790Abstract: Ready-to-use preshaped, prefabricated cured structural components are prepared in a variety of shapes and sizes to be used in the fabrication of dental appliances. Preferably the structural components are fabricated of a fiber-reinforced composite material comprising fibers impregnated with a polymeric matrix. The polymeric matrix is partially or fully cured to the point of sufficient hardness to provide a ready-to-use structural component for use in the fabrication of dental appliances such as orthodontic retainers, bridges, space maintainers, tooth replacement appliances, splints, crowns, partial crowns, dentures, posts, teeth, jackets, inlays, onlays, facings, veneers, facets, implants, abutments, cylinders, and connectors.Type: GrantFiled: November 12, 1998Date of Patent: February 13, 2001Assignee: Jeneric/Pentron IncorporatedInventors: Ajit Karmaker, Martin L. Schulman, Arun Prasad
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Patent number: 6132215Abstract: A hybrid fiber-reinforced structural component for dental restorations, wherein the hybrid reinforcing fibers comprise a core having a composite sheath bonded thereto. Preferably, the core comprises a material having a high modulus, such as tungsten, tantalum, niobium, boron or carbon. The composite sheath comprises fibers disposed within a polymeric matrix material, preferably the fibers glass or polyethylene fibers. The hybrid fiber-reinforced composite is particularly useful as a structural component for bridges or for reinforcement of a tooth restoration after endodontic treatment.Type: GrantFiled: April 15, 1998Date of Patent: October 17, 2000Assignee: Jeneric/Pentron IncorporatedInventors: Arun Prasad, Ajit Karmaker
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Patent number: 6103383Abstract: A new nickel-chromium alloy having high rigidity, castability, corrosion and oxidation resistance and easy workability is disclosed. The alloy comprises from about 45 to 81% nickel by weight, from about 13 to 25% chromium by weight, from about 3 to 15% tungsten by weight, and silicon and aluminum in the range from about 1 to about 6% by weight each. The new alloy has a high concentration of tungsten.Type: GrantFiled: January 27, 1998Date of Patent: August 15, 2000Assignee: Jeneric/Pentron IncorporatedInventor: Arun Prasad
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Patent number: 6039569Abstract: The present invention relates to unique dental structures such as bridges and crowns. The bridge comprises a structural component such as a fiber reinforced polymeric matrix bar disposed within interproximal cavities located in the distal occlusal surface of the mesial abutment tooth and the mesial occlusal surface of the distal abutment tooth. A structural wrap and/or occlusal strip comprising fibers embedded within a polymeric matrix can also be employed where the wrap is attached to one or both abutment teeth and one or both sides of the structural component. The occlusal strip is attached to the occlusal surface of both of the abutment teeth, spans the edentulous area, and is attached to the top surface of the structural component. Meanwhile, the crown comprises a wrap disposed around and adhered to a damaged natural tooth and may have an occlusal strip adhered to the occlusal surface of the natural tooth where the wrap is disposed around the edge of the occlusal strip.Type: GrantFiled: August 7, 1998Date of Patent: March 21, 2000Assignee: Jeneric/Pentron IncorporatedInventors: Arun Prasad, Ajit Karmaker, Elie Zammarieh, Grant P. Day
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Patent number: 6030220Abstract: A fiber-reinforced composite material for use in dental restorations such as dental bridges, splints, veneers, and laminates, wherein the composite material comprises a glass fiber material which has been heat treated at a temperature less than or equal to the annealing temperature of the glass for a length of time effective to prevent separation and fraying of the edges of the material upon cutting. The heat treatment therefore greatly enhances the ease of preparation of the dental restorations.Type: GrantFiled: September 24, 1997Date of Patent: February 29, 2000Assignee: Jeneric/Pentron IncorporatedInventors: Ajit Karmaker, Arun Prasad
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Patent number: 6013694Abstract: A composite for a dental restoration is presented comprising ground, densified, embrittled glass fibers together with fillers and a polymeric matrix precursor composition. The ground, densified, embrittled glass fibers are obtained by grinding glass fibers which have been densified and embrittled by heating glass fibers at a temperature substantially below the softening point of the glass fibers, without significant fusion or melting together of the fibers. The composite is particularly useful as a direct filling material, in that it has the feel and workability of an amalgam.Type: GrantFiled: October 16, 1997Date of Patent: January 11, 2000Assignee: Jeneric/Pentron IncorporatedInventors: Weitao Jia, Martin L. Schulman, Arun Prasad, Bruce Alpert
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Patent number: 5921778Abstract: A reinforced composite material for use in dental restorations such as dental bridges, splints, veneers, and laminate comprising a hybrid woven material formed of glass yarns and synthetic yarns. Suitable synthetic yarns comprise polyethylene, polypropylene, polyester, acrylic fibers, or a combination thereof. The hybrid woven material of the present invention does not fray upon cutting, which greatly enhances ease of preparation of the fiber-reinforced dental restorations.Type: GrantFiled: March 19, 1998Date of Patent: July 13, 1999Assignee: Jeneric/Pentron IncorporatedInventors: Ajit Karmaker, Arun Prasad
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Patent number: 5684103Abstract: In a polymerizable dental restorative resin composition useful as a dental composite resin and/or a denture/denture base material comprising at least one binder resin, a diluent monomer, at least one filler, optionally, a photopolymerization system comprising an initiator for initiating polymerization of the composite resin upon exposure to visible light and an accelerator, and an initiator for initiating polymerization of the composite resin upon application of heat, the improvement imparting shelf stability and substantially eliminating discoloration is provided comprising the initiator for initiating polymerization upon application of heat having the general formula:R--N.dbd.N--R'wherein R and R' can be the same or different, and are selected from the group consisting of oxygen-free aliphatic, cycloaliphatic, aromatic, and heterocyclic moieties.Type: GrantFiled: March 31, 1997Date of Patent: November 4, 1997Assignee: Jeneric/Pentron IncorporatedInventors: Weitao Jia, Arun Prasad
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Patent number: 5599406Abstract: A copper-aluminum-indium alloy approaches gold in spectral appearance, tarnish resistance and mechanical durability, by virtue of a specific formulation and microstructure. The formulation consists of the following essential ingredients by total weight, in a copper matrix: from 7 to 12% of aluminum, from 5 to 11% of indium, and no more than 3% of a essentially non-ferromagnetic remainder. The required microstructure is in the form an essentially ternary alloy having a quenched single phase, an average grain size of no more than 100 .mu.m in diameter. Preferably, the above specified 3% remainder includes: a modifier selected from the class consisting of boron, silicon, lithium, magnesium, zinc and phosphorous; a strengthener selected from the class consisting of silver, gold, palladium, platinum, iridium, ruthenium and rhodium; and a system stabilizer, preferably selected from the class consisting of yttrium, cerium, lanthanum, hafnium, zirconium, chromium, titanium, nickel, iron and manganese.Type: GrantFiled: January 4, 1993Date of Patent: February 4, 1997Assignee: Gemetals CorporationInventors: Arun Prasad, Michael Weston, Grant Bauer
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Patent number: 5462437Abstract: A dental alloy is provided which is compatible with a wide variety of composites and porcelain compositions. The alloy has a melting range of between about 870.degree. C. and 1230.degree. C. and a coefficient of thermal expansion of between 15.5.times.10.sup.-6 and 17.5.times.10.sup.-6 in/in/.degree. C. when heated from room temperature to 500.degree. C. The alloy contains between one and 85 percent by weight gold, between two and 65 percent by weight of a thermal expansion adjuster, between 0.25 and 34 percent by weight of a strengthener and oxide former, up to about one percent by weight grain refiner, and up to about 0.25 percent by weight deoxidizer.Type: GrantFiled: November 10, 1993Date of Patent: October 31, 1995Assignee: Jeneric/Pentron IncorporatedInventors: Arun Prasad, Martin Schulman
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Patent number: 5423680Abstract: A dental alloy is provided which is free of palladium, gallium and copper and which is compatible with a wide variety of composites and porcelain compositions. The alloy has a melting range of between about 870.degree. C. and 1230.degree. C. and a coefficient of thermal expansion of between 15.5.times.10.sup.-6 and 17.5.times.10.sup.-6 in/in/.degree. C. when heated from room temperature to 500.degree. C. The alloy contains between about 40 and 80 percent by weight gold, between 5 and 50 percent by weight of thermal expansion adjuster, between two and 15 percent by weight strengthener and oxide former, up to about 1.5 percent by weight grain refiner, and up to about 0.25 percent by weight deoxidizer.Type: GrantFiled: November 10, 1993Date of Patent: June 13, 1995Assignee: Jeneric/Pentron, IncorporatedInventor: Arun Prasad
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Patent number: 5348475Abstract: A trimodal method of curing dental composite restorative materials involves the use of visible light illumination for the initial curing of the composite resin and a combination of dry heat and vacuum for the complete cure of the composite restorative materials. More specifically, the method for preparing dental restorative materials includes the steps of forming a dental restoration from a composite resin of a type conventionally employed in the dental profession, in which the composite resin includes a photosensitizing system for initiating polymerization of the composite resin upon exposure to visible light, an initiator for initiating polymerization upon application of heat and at least one filler; exposing the thus prepared restoration to a source of visible light to at least partially cure said composite resin and then subjecting the thus prepared restoration to a combination of heat and vacuum to complete polymerization of said complete resin.Type: GrantFiled: April 22, 1993Date of Patent: September 20, 1994Assignee: Jeneric/Pentron Inc.Inventors: Samuel Waknine, Arun Prasad, Weitao Jia
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Patent number: D421121Type: GrantFiled: October 27, 1998Date of Patent: February 22, 2000Assignee: Jeneric/Pentron IncorporatedInventors: Arun Prasad, Peter C. Gable, Jr.