Patents by Inventor Paul D. Hammesfahr
Paul D. Hammesfahr 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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Publication number: 20020198285Abstract: A dental adhesive composition has an adhesive component and an activator component. The adhesive composition has a volatile organic solvent component, one or more polymerizable (meth)acrylate compounds optionally containing fillers, and a polymerization photoinitiator. The adhesive component may also be a substantially homogeneous mixture of one or more polymerizable (meth)acrylate compounds and an effective amount of a photoinitiator, without a solvent. The activator component includes an aromatic sulfinate salt and an activator component solvent. A method for adhering a restorative to a dental surface includes preparing the surface for restoration; applying a mixture of an adhesive component and an activator component to the prepared cavity, thereby forming a coated cavity surface; and, applying a direct or indirect dental restorative to the coated cavity surface.Type: ApplicationFiled: April 5, 2002Publication date: December 26, 2002Applicant: DENTSPLY Research & Development Corp.Inventors: Junjie Sang, Paul D. Hammesfahr
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Publication number: 20020160333Abstract: A multi-component, mixing, storage and dispensing package (10) has a housing 11, a displaceable cavity block (20) having at least one cavity (21) therein. A vent spike block (40) having at least one spike (42) held in an opposing relation to at least one cavity (21) is provided within the housing (11). When cavity block (21) is caused to move toward the vent spike block (40) spike (42) is caused to enter a cavity (21). A vent (43) is in fluid communication through the spike (42) with a mix channel (51) and a mixing and dispensing tip (50).Type: ApplicationFiled: April 11, 2002Publication date: October 31, 2002Applicant: DENTSPLY Research & Development Corp.Inventors: Paul R. Pierson, Paul D. Hammesfahr
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Patent number: 6391940Abstract: A preferred embodiment of the invention provides a composition and method of treating dental metal. The composition includes a polymerizable aryl compound having at least one carboxylic acid group and at least one polymerizable group, and a polymerizable compound having at least one polymerizable group and at least one phosphorous containing group. A preferred composition includes at least 50 percent by weight of a volatile organic solvent, at least 15 percent by weight of one or more polymerizable acrylate compounds and an effective amount of a photoinitiator. At least a portion of the polymerizable compounds are multifunctional polymerizable compounds having at least three acrylate moieties. The polymerizable compounds are substantially soluble in the solvent. The composition is adapted to form a polymeric material which is adapted to adhere to metal and ceramics and to dentin. Compositions of the invention have superior adhesion to dental metals and tooth without separately acid etching dentin or enamel.Type: GrantFiled: June 29, 1999Date of Patent: May 21, 2002Assignee: Dentsply Research & Development Corp.Inventors: Gordon Brian Blackwell, Kewang Lu, Chin-Teh Huang, Mingxin Fan, Paul D. Hammesfahr, Xiuling Wang, Junjie Sang
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Patent number: 6387980Abstract: The invention provides dental composition system having curable liquid which is useful alone as a light curable composition and which is useful by mixing with a powder in preselected proportions to form dual cure compositions. The composition system is useful as bonding agent, cement, liner, base, restorative, pit and fissure sealants, and/or core build-up material, having improved adhesion to dentin. After storing the powder and the liquid in separate containers for at least two weeks and then mixing a portion of the powder and a portion of the liquid to form a mixture, the polymerizable compound polymerizes within 20 minutes of the mixing to form a first polymeric material having a flexural strength of at least 50 MPa, and an expansion in water at 37° C. after 90 days of less than 1 percent by volume.Type: GrantFiled: November 29, 2000Date of Patent: May 14, 2002Assignee: Dentsply Research & Development Corp.Inventors: Kewang Lu, Paul D. Hammesfahr
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Patent number: 6353040Abstract: A dental composite material includes a hardenable resin matrix and a filler component. The filler component includes (a) a first plurality of preferably glass particles having an average particle size of from about 1 to about 10 micrometers; (b) a second plurality of preferably glass particles having an average particle size of from about 0.1 to about 1 micrometers; and, (c) a plurality of filler particles having an average particle size of from about 0.01 to about 0.04 micrometers. A method according to the invention includes compacting a dental composite material into a prepared tooth cavity, wherein the material has a packability index above about 300 g/mm2.Type: GrantFiled: July 6, 1998Date of Patent: March 5, 2002Assignee: Dentsply Research & Development Corp.Inventors: John C. Subelka, Steven R. Jefferies, Donald A. Kapperman, Paul D. Hammesfahr, Paul A. Silver
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Publication number: 20020016378Abstract: A photopolymerizable material is exposed to light to effect curing. A portion of the material is exposed to light in a conventional manner, while at least one other portion of the material is masked from direct exposure to the light by use of a mask (10) having at least one mask segment (11) which either completely or at least partially blocks the light. In this manner, the polymerization stress associated with the cured materials is limited or minimized due to extended molecular relaxation promoted by this controlled or hybrid curing technique. Also according to the invention, different segments (30, 31) of a material to be cured (22) are exposed to different wavelengths of light energy (21) or one such segment (30, 31) is exposed to light energy while another such segment is not.Type: ApplicationFiled: March 15, 2001Publication date: February 7, 2002Inventors: Xiaoming Jin, Paul D. Hammesfahr
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Publication number: 20010051671Abstract: The invention provides dental composition system having curable liquid which is useful alone as a light curable composition and which is useful by mixing with a powder in preselected proportions to form dual cure compositions. The composition system is useful as bonding agent, cement, liner, base, restorative, pit and fissure sealants, and/or core build-up material, having improved adhesion to dentin. After storing the powder and the liquid in separate containers for at least two weeks and then mixing a portion of the powder and a portion of the liquid to form a mixture, the polymerizable compound polymerizes within 20 minutes of the mixing to form a first polymeric material having a flexural strength of at least 50 MPa, and an expansion in water at 37° C. after 90 days of less than 1 percent by volume.Type: ApplicationFiled: November 29, 2000Publication date: December 13, 2001Inventors: Kewang Lu, Paul D. Hammesfahr
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Patent number: 6262142Abstract: A method and material for forming translucent wear resistant dental enamel and the dental enamel material formed which has an opacity less than 50 percent and a localized wear volume loss of less than 0.025 mm3. The dental enamel material is formed from a polymerizable matrix and a filler. The material for forming translucent wear resistant dental enamel having an opacity less than 50 percent, a localized wear volume loss of less than 0.025 mm3 and a localized extended wear volume loss of less than 0.04 mm3, comprises a polymerizable matrix forming liquid and inorganic filler particles. The liquid comprises polymerizable material having a first refractive index. The filler comprising a first plurality of particles having a second refractive index. The first plurality of particles being formed from a low and a high median particle size plurality of particles. The low median particle size plurality of particles having a median particle size between 0.1 and 1.0 micrometers.Type: GrantFiled: July 12, 1999Date of Patent: July 17, 2001Assignee: DENTSPLY Research & DevelopmentInventors: Xiuling Wang, John C. Subelka, Steven R. Jefferies, Paul D. Hammesfahr, Paul A. Silver
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Patent number: 6211264Abstract: The invention provides dental composition system having curable liquid which is useful alone as a light curable composition and which is useful by mixing with a powder in preselected proportions to form dual cure compositions. The composition system is useful as bonding agent, cement, liner, base, restorative, pit and fissure sealants, and/or core build-up material, having improved adhesion to dentin. After storing the powder and the liquid in separate containers for at least two weeks and then mixing a portion of the powder and a portion of the liquid to form a mixture, the polymerizable compound polymerizes within 20 minutes of the mixing to form a first polymeric material having a flexural strength of at least 50 MPa, and an expansion in water at 37° C. after 90 days of less than 1 percent by volume.Type: GrantFiled: July 12, 1999Date of Patent: April 3, 2001Assignee: Dentsply Research & Development Corp.Inventors: Kewang Lu, Paul D. Hammesfahr
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Patent number: 6191190Abstract: A composition and method of treating a dental tooth. The composition includes a polymerizable aryl compound having at least one carboxylic acid group and at least one polymerizable group, and a polymerizable compound having at least one polymerizable group and at least one phosphorous containing group. A preferred composition includes at least 50 percent by weight of a volatile organic solvent, at least 15 percent by weight of one or more polymerizable acrylate compounds and an effective amount of a photoinitiator. At least a portion of the polymerizable compounds are multifunctional polymerizable compounds having at least three acrylate moieties. The polymerizable compounds are substantially soluble in the solvent. The composition is adapted to form a polymeric material which is adapted to adhere to dentin. Compositions of the invention have superior adhesion to tooth without separately acid etching dentin or enamel.Type: GrantFiled: May 18, 1998Date of Patent: February 20, 2001Assignee: Dentsply Research & Development Corp.Inventors: Gordon Brian Blackwell, Kewang Lu, Chin-Teh Huang, Mingxin Fan, Paul D. Hammesfahr
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Patent number: 5981620Abstract: The invention provides polymerizable dental, compounds, compositions, including the compounds and products for mixing the compositions and methods of using the compositions. Aryl acid compounds are provided in accordance with the invention. The compositions include at least one polymerizable aryl acid compound, an effective amount of a polymerization initiator, and at least 10 percent by weight of ceramic, metal and/or metal oxide filler particles having a particle size less than 500 microns. The dental products of the invention include a polymerizable composition in an enclosure having at least two chambers separated by a wall adapted to be ruptured prior to or during mixing of the composition. Compositions of the invention are preferred for use in these enclosures. Core build up material including a polymerizable acid containing compound is used to support dental crowns and adhere them to teeth in accordance with the invention.Type: GrantFiled: October 17, 1997Date of Patent: November 9, 1999Assignee: Dentsply Research & Development Corp.Inventors: Paul D. Hammesfahr, Kewang Lu, Paul A. Silver
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Patent number: 5973022Abstract: The invention provides dental composition system having curable liquid which is useful alone as a light curable composition and which is useful by mixing with a powder in preselected proportions to form dual cure compositions. The composition system is useful as bonding agent, cement, liner, base, restorative, pit and fissure sealants, and/or core build-up material, having improved adhesion to dentin. After storing the powder and the liquid in separate containers for at least two weeks and then mixing a portion of the powder and a portion of the liquid to form a mixture, the polymerizable compound polymerizes within 20 minutes of the mixing to form a first polymeric material having a flexural strength of at least 50 MPa, and an expansion in water at 37.degree. C. after 90 days of less than 1 percent by volume.Type: GrantFiled: November 1, 1996Date of Patent: October 26, 1999Assignee: DENTSPLY Research & Development Corp.Inventors: Kewang Lu, Paul D. Hammesfahr
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Patent number: 5906490Abstract: The invention provides a kit and method for the preparation of dental products. First, second and third materials are provided in labeled containers. Preferably the first, second and third materials are pastes or powders. The first material has a lightness value (L.sub.1) when formed into a least opaque layer. The second material has a lightness value (L.sub.2) when formed into a less opaque layer. The third material has a lightness value (L.sub.3) when formed into a most opaque layer. The third lightness value is greater than the second lightness value, which is greater than the first lightness value. The lightness value differences between the third lightness value (L.sub.3) and the first lightness value (L.sub.1) are less than 10 CIE L*a*b units.Type: GrantFiled: October 6, 1997Date of Patent: May 25, 1999Assignee: Ceramco Inc.Inventors: Carolyn M. Kramer Primus, Paul D. Hammesfahr
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Patent number: 5710194Abstract: The invention provides polymerizable dental, compounds, compositions, including the compounds and products for mixing the compositions and methods of using the compositions. Aryl acid compounds are provided in accordance with the invention. The compositions include at least one polymerizable aryl acid compound, an effective amount of a polymerization initiator, and at least 10 percent by weight of ceramic, metal and/or metal oxide filler particles having a particle size less than 500 microns. The dental products of the invention include a polymerizable composition in an enclosure having at least two chambers separated by a wall adapted to be ruptured prior to or during mixing of the composition. Compositions of the invention are preferred for use in these enclosures. Core build up material including a polymerizable acid containing compound is used to support dental crowns and adhere them to teeth in accordance with the invention.Type: GrantFiled: February 15, 1996Date of Patent: January 20, 1998Assignee: Dentsply Research & Development Corp.Inventors: Paul D. Hammesfahr, Kewang Lu, Paul A. Silver
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Patent number: 5554028Abstract: A method of preparing an impression of dentition in the oral cavity is provided that overcomes a problem of transfer of inhibitors left by latex gloves that interfere with platinum catalyzed hydrosilation reactions. The method involves applying a surfactant, preferably with peroxide, to the area that is to have its impression taken substantially immediately before applying the impression taking material, rinsing the composition from the area and proceeding with the taking of the dental impression. Preferably the decontaminating composition consists essentially of surfactant, especially polyoxyethylene surfactants, hydrogen peroxide and water.Type: GrantFiled: March 24, 1994Date of Patent: September 10, 1996Assignee: Dentsply Research & Development Corp.Inventors: Robert V. Hare, Paul D. Hammesfahr
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Patent number: 5367002Abstract: The invention provides dental composite compositions formed by mixing a curable liquid composition with a powder in preselected proportions. The composite compositions formed are useful as cement, liner, base, restorative, pit and fissure sealants, and/or core build-up material, etc. having improved adhesion to dentin. These composite compositions include polyalkenoic acid, filler which provides elutable cations which are reactive with the polyalkenoic acid and fluoride ion, water to provide for elution of cations reactive with polyalkenoic acid, polymerizable monomer and/or prepolymer composition, unsaturated organic acid having 1 or more polymerizable groups and a catalyst system for polymerization. Optionally the composites include inert reinforcing filler for strength, aesthetics, and radiopacity.Type: GrantFiled: February 6, 1992Date of Patent: November 22, 1994Assignee: Dentsply Research & Development Corp.Inventors: Chin-Teh Huang, Paul D. Hammesfahr, Steven R. Jefferies
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Patent number: 5304586Abstract: One component, visible light-cured dental restorative compositions having fluoride release properties for the purpose of reducing the chances of secondary caries are provided. The compositions include inorganic particulate fluoride leachable glass.Type: GrantFiled: August 2, 1991Date of Patent: April 19, 1994Assignee: Dentsply Research & Development Corp.Inventors: Paul D. Hammesfahr, Paul S. Danielson, Robert C. Campbell
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Patent number: 5177120Abstract: Disclosed is a new urethane polyacrylate having at least one terminal isocyanato acrylic pendent radical. Preferably the molecular chain within the acrylate caps has been extended with a polyhydroxy compound just before final end capping with isocyanato acrylic. The isocyanato acrylic is preferably isocyanato ethyl methacrylate and the urethane is diisocyanate capped polyether and the polyether radical is oxyalkylene. The method for producing the urethane polyacrylate involves end capping a polyol with diisocyanate yielding a reaction product with two reactive equivalents of isocyanate and then capping less than all of the isocyanate with a hydroxyacrylate, after which the remaining isocyanate is reacted with polyol to provide chain extension. The chain extending polyol is then capped with a isocyanato acrylic.Type: GrantFiled: November 13, 1987Date of Patent: January 5, 1993Assignee: Dentsply Research & Development Corp.Inventors: Pamela H. Hare, Paul D. Hammesfahr
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Patent number: 4867682Abstract: A dental impression tray and method of using it to form in a light-polymerizable impression material an impression of a portion of dental anatomy in an oral cavity, the tray being formed of transparent material, preferably clear plastic, and molded into a channel-like shape defined by walls capable of having visible actinic light applied to the walls transmitted both through and within the walls. At least some of the outer edge portions of the tray are beveled, guiding light that has entered the walls of the tray against exiting loss that would not be effective in initiating polymerization of the impression material.Type: GrantFiled: November 13, 1987Date of Patent: September 19, 1989Assignee: Dentsply Research & Development Corp.Inventors: Paul D. Hammesfahr, Steven R. Jefferies, Ronald L. Sitzema, Jr.
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Patent number: 4867680Abstract: A dental impression package pre-loaded with dental impression material adapted for taking accurate impressions of a patient's teeth and/or gums by professional personnel is provided. The impression material used is flowable to a desired degree and has a viscosity of substantially one million centipoises. Packaging a pre-loaded dental impression tray is accomplished by first quickly immersing the loaded tray in a solution of natural latex for a few seconds and then quickly removing the coated product followed by quickly immersing it in a coagulating solution of acetic acid for a few seconds to stabilize the latex coating; withdrawing the stabilized coated product; drying it; and suitably packaging the product for storage and sale. If the impression material is of a light-curable nature, the packaging is of light-opaque nature.Type: GrantFiled: March 31, 1987Date of Patent: September 19, 1989Assignee: Dentsply Research & Development Corp.Inventors: Pamela H. Hare, Robert V. Hare, Paul D. Hammesfahr