Patents by Inventor Thomas C. Chadwick

Thomas C. Chadwick 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).

  • Publication number: 20100119431
    Abstract: The present invention relates generally dental ceramics. In particular, invention relates to a high strength, high reliability, dental glass-ceramic that contains uniform, ellipsoidal reinforcing leucite crystals.
    Type: Application
    Filed: November 7, 2008
    Publication date: May 13, 2010
    Applicant: Den-Mat Holdings LLC
    Inventors: Robert Ibsen, Xiaohui Chen, Michael J. Cattell, Jacques V. Riddell, Thomas C. Chadwick
  • Publication number: 20090081104
    Abstract: The present invention provides for the production of a single frit, dental porcelain, glass-ceramic containing small, uniformly dispersed, single leucite crystals of ellipsoidal habit and very uniform size.
    Type: Application
    Filed: September 21, 2007
    Publication date: March 26, 2009
    Applicant: Den-Mat Holdings LLC
    Inventors: Robert Ibsen, Xiaohui Chen, Michael J. Cattell, Jacques V. Riodel, Thomas C. Chadwick
  • Patent number: 7175700
    Abstract: A family of radiopaque glasses comprising silicon dioxide (15–30%), ytterbium oxide (5–35%), barium oxide (30–50%) and fluoride (5–20%), all by weight. The family of glasses all exhibit high radiopacity with refractive indices varying from 1.508–1.592 and translucency ranging from clear to moderately opaque. These glasses can be incorporated into dental composites to provide radiopaque dental restoratives with a desired translucence and appearance.
    Type: Grant
    Filed: July 2, 2004
    Date of Patent: February 13, 2007
    Assignee: Den-Mat Corporation
    Inventors: Thomas C. Chadwick, Rebecca K. Santiago
  • Patent number: 6824704
    Abstract: An aqueous gel useful for bleaching teeth comprising: (i) water; (ii) polyacrylic acid thickening agent; (iii) hydrogen peroxide bleaching agent; and (iv) aminocarboxylic acid/salt stabilizing agent. Preferably the polyacrylic acid is an easy to disperse carbomer and the gels contain high concentrations (20 to 40% by weight) of hydrogen peroxide. The gels exhibit room temperature stability, both with respect to gel stability and hydrogen peroxide decomposition, sufficient to eliminate the need for constant refrigeration. A method for using the gels to bleach teeth is also disclosed.
    Type: Grant
    Filed: October 15, 2003
    Date of Patent: November 30, 2004
    Assignee: The Gillette Company
    Inventors: Thomas C. Chadwick, Heather L. Hunt
  • Patent number: 6779590
    Abstract: Methods for making molding casts by a process typically referred to as “investment casting” using a novel composition is described. The composition is a phosphate bonded material that contains mono-ammonium phosphate (MAP), magnesium oxide and silica filler (quartz, cristobalite, or a mixture thereof). It has been discovered that controlling the amount and ratio of these components has a significant impact on gas permeability (porosity), set time, cast smoothness and cast softness. The most outstanding feature of the new investments is the short mold fabrication and processing time that they allow due to their high gas permeability. The investments can be placed in a burn out furnace while still wet and can be heated rapidly to the firing temperature. The casts can be broken by sandblasting the casts with glass beads. Molds made from the casts have smooth surfaces indicating that the casts are free of visible inclusions and other defects.
    Type: Grant
    Filed: March 10, 2003
    Date of Patent: August 24, 2004
    Assignee: Den-Mat Corporation
    Inventors: Rachel R. Pineda, Thomas C. Chadwick
  • Publication number: 20040079920
    Abstract: An aqueous gel useful for bleaching teeth comprising: (i) water; (ii) polyacrylic acid thickening agent; (iii) hydrogen peroxide bleaching agent; and (iv) aminocarboxylic acid/salt stabilizing agent. Preferably the polyacrylic acid is an easy to disperse carbomer and the gels contain high concentrations (20 to 40% by weight) of hydrogen peroxide. The gels exhibit room temperature stability, both with respect to gel stability and hydrogen peroxide decomposition, sufficient to eliminate the need for constant refrigeration. A method for using the gels to bleach teeth is also disclosed.
    Type: Application
    Filed: October 15, 2003
    Publication date: April 29, 2004
    Inventors: Thomas C. Chadwick, Heather L. Hunt
  • Publication number: 20030170592
    Abstract: An aqueous gel useful for bleaching teeth comprising: (i) water; (ii) polyacrylic acid thickening agent; (iii) hydrogen peroxide bleaching agent; and (iv) aminocarboxylic acid/salt stabilizing agent. Preferably the polyacrylic acid is an easy to disperse carbomer and the gels contain high concentrations (20 to 40% by weight) of hydrogen peroxide. The gels exhibit room temperature stability, both with respect to gel stability and hydrogen peroxide decomposition, sufficient to eliminate the need for constant refrigeration. A method for using the gels to bleach teeth is also disclosed.
    Type: Application
    Filed: March 13, 2003
    Publication date: September 11, 2003
    Inventors: Thomas C. Chadwick, Heather L. Hunt
  • Publication number: 20030164230
    Abstract: Methods for making molding casts by a process typically referred to as “investment casting” using a novel composition is described. The composition is a phosphate bonded material that contains mono-ammonium phosphate (MAP), magnesium oxide and silica filler (quartz, cristobalite, or a mixture thereof). It has been discovered that controlling the amount and ratio of these components has a significant impact on gas permeability (porosity), set time, cast smoothness and cast softness. The most outstanding feature of the new investments is the short mold fabrication and processing time that they allow due to their high gas permeability. The investments can be placed in a burn out furnace while still wet and can be heated rapidly to the firing temperature. The casts can be broken by sandblasting the casts with glass beads. Molds made from the casts have smooth surfaces indicating that the casts are free of visible inclusions and other defects.
    Type: Application
    Filed: March 10, 2003
    Publication date: September 4, 2003
    Inventors: Rachel R. Pineda, Thomas C. Chadwick
  • Patent number: 6555020
    Abstract: An aqueous gel useful for bleaching teeth comprising: (i) water; (ii) polyacrylic acid thickening agent; (iii) hydrogen peroxide bleaching agent; and (iv) aminocarboxylic acid/salt stabilizing agent. Preferably the polyacrylic acid is an easy to disperse carbomer and the gels contain high concentrations (20 to 40% by weight) of hydrogen peroxide. The gels exhibit room temperature stability, both with respect to gel stability and hydrogen peroxide decomposition, sufficient to eliminate the need for constant refrigeration. A method for using the gels to bleach teeth is also disclosed.
    Type: Grant
    Filed: October 28, 1999
    Date of Patent: April 29, 2003
    Assignee: Den-Mat Corporation
    Inventors: Thomas C. Chadwick, Heather L. Hunt
  • Patent number: 6551396
    Abstract: An investment composition is described for use in investment casting (also called lost wax casting). The composition is a phosphate bonded material that contains mono-ammonium phosphate (MAP), magnesium oxide and silica filler (quartz, cristobalite, or a mixture thereof). It has been discovered that controlling the amount and ratio of these components has a significant impact on gas permeability (porosity), set time, cast smoothness and cast softness. The most outstanding feature of the new investments is the short mold fabrication and processing time that they allow due to their high gas permeability. The investments can be placed in a bum out furnace while still wet and can be heated rapidly to the firing temperature. The casts can be broken by sandblasting the casts with glass beads. Molds made from the casts have smooth surfaces indicating that the casts are free of visible inclusions and other defects.
    Type: Grant
    Filed: June 27, 2001
    Date of Patent: April 22, 2003
    Assignee: Den-Mat Corporation
    Inventors: Rachel R. Pineda, Thomas C. Chadwick
  • Patent number: 6511654
    Abstract: The instant invention relates to an anhydrous dentifrice (toothpaste, brushing gel, etc . . . ) The dentifrice is a homogeneous mixture of the following compounds: (1) organic polyols, such as glycerin; (2) cooked starch gelling agents; (3) mildly abrasive fillers such as silica, alumina and dicalcium phosphate; and, optionally, (4) compounds selected from the group consisting of anti-caries agents, anti-plaque agents, anti-calculus agents, bleaching agents, peroxide stabilizers, desensitizing agents, whiteners, anti-stain agents, breath fresheners, flavorants, sweeteners, colorants, buffers, surfactants, and anti-bacterial agents, with the proviso that if bleaching agents are employed then peroxide stabilizers must also be employed. Preferably, the dentifrice does not contain any gelling agent other than the cooked starch particles.
    Type: Grant
    Filed: December 21, 2000
    Date of Patent: January 28, 2003
    Assignee: Den-Mat Corporation
    Inventors: Robert Ibsen, Rachel R. Pineda, Thomas C. Chadwick, Alan Matthews
  • Patent number: 6458340
    Abstract: A substantially anhydrous gel useful for bleaching teeth comprising: (i) at least 25% by weight of organic polyol; (ii) less than 3% by weight polyacrylic acid thickening agent; (iii) at least 10% by weight carbamide peroxide (or a chemically equivalent amount of another bleaching agent, such as 3% by weight hydrogen peroxide); (iv) neutralizing agent; (v) chelating agents; (vi) desensitizing agent; and (vii) miscellaneous ingredients such as Cirtoxain® and flavorants. The organic polyol is preferably glycerin. The polyacrylic acid thickening agent is preferably a carbomer. The desensitizing agent is preferably potassium nitrate, strontium chloride, potassium citrate, strontium nitrate, or a similarly effective alkali or alkaline earth metal salt of an organic or inorganic acid.
    Type: Grant
    Filed: November 12, 1999
    Date of Patent: October 1, 2002
    Assignee: Den-Mat Corporation
    Inventors: Robert L. Ibsen, Alan Mathews, Thomas C. Chadwick, Xinyi Yu
  • Publication number: 20020006386
    Abstract: The instant invention relates to an anhydrous dentifrice (toothpaste, brushing gel, etc . . . ) The dentifrice is a homogeneous mixture of the following compounds: (1) organic polyols, such as glycerin; (2) cooked starch gelling agents; (3) mildly abrasive fillers such as silica, alumina and dicalcium phosphate; and, optionally, (4) compounds selected from the group consisting of anti-caries agents, anti-plaque agents, anti-calculus agents, bleaching agents, peroxide stabilizers, desensitizing agents, whiteners, anti-stain agents, breath fresheners, flavorants, sweeteners, colorants, buffers, surfactants, and anti-bacterial agents, with the proviso that if bleaching agents are employed then peroxide stabilizers must also be employed. Preferably, the dentifrice does not contain any gelling agent other than the cooked starch particles.
    Type: Application
    Filed: December 21, 2000
    Publication date: January 17, 2002
    Inventors: Robert Ibsen, Rachel R. Pineda, Thomas C. Chadwick, Alan Matthews
  • Patent number: 5375187
    Abstract: A method and apparatus for heat-curing light-cured resins by means of placing the resin in an oven attachment coupled to a high intensity light source, such that heat generated by the light source raises the temperature within the oven attachment to at least 140.degree. C., and maintains the temperature above 140.degree. C. for at least 10 minutes. The oven attachment has a body fabricated from a rigid material having a relatively low thermal conductivity. The oven attachment is fashioned to fit over the light outlet of a conventional light source. The oven attachment is preferably held in place by the same mechanism that holds a light-curing "wand" to the light source. The light source is turned on for a heating period of approximately 15 minutes, causing the temperature within an oven chamber within the oven attachment to rise. Upon completion of the heating period, the light source is turned off and the heat-cured restoration may be removed.
    Type: Grant
    Filed: February 12, 1993
    Date of Patent: December 20, 1994
    Assignee: Den-Mat Corporation
    Inventors: Robert L. Ibsen, Thomas C. Chadwick, David F. Ouellet
  • Patent number: 5360770
    Abstract: A glass composition, containing barium oxide, which provides a source of leachable fluoride and which can be incorporated into a dental cement composition which, when cured, is radiopaque and translucent.
    Type: Grant
    Filed: January 7, 1992
    Date of Patent: November 1, 1994
    Assignee: Den-Mat Corporation
    Inventor: Thomas C. Chadwick
  • Patent number: 5009709
    Abstract: A dental porcelain having the following composition:______________________________________ Ingredient Weight by Percent ______________________________________ SiO.sub.2 52.7%-64.6% Al.sub.2 O.sub.3 6.3%-16.4% Li.sub.2 O 0%-0.5% Na.sub.2 O 3.9%-14.2% K.sub.2 O 4.5%-11.7% MgO 0%-.3% CaO 1.6%-3.3% Sro 0.9%-2.3% BaO 0.3%-8.1% TiO.sub.2 0.1%-3.6% B.sub.2 O.sub.3 0.2%-5.0% ______________________________________made by blending powdered first-fire frit with pacifiers, heating this first-fire frit to 2000.degree. F., and rapidly cooling the charge.
    Type: Grant
    Filed: July 3, 1990
    Date of Patent: April 23, 1991
    Assignee: Den-Mat Corporation
    Inventors: Robert L. Ibsen, Thomas C. Chadwick, Sally A. Pritchard
  • Patent number: 4150233
    Abstract: This invention relates to a new water-soluble, tetraphenyl substituted pyridinium salt compound and to a novel process of producing it. This compound finds use as a selective analytical reagent for certain large anions of low charge density.
    Type: Grant
    Filed: May 16, 1977
    Date of Patent: April 17, 1979
    Inventor: Thomas C. Chadwick