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).
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Publication number: 20100119431Abstract: 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: ApplicationFiled: November 7, 2008Publication date: May 13, 2010Applicant: Den-Mat Holdings LLCInventors: Robert Ibsen, Xiaohui Chen, Michael J. Cattell, Jacques V. Riddell, Thomas C. Chadwick
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Publication number: 20090081104Abstract: 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: ApplicationFiled: September 21, 2007Publication date: March 26, 2009Applicant: Den-Mat Holdings LLCInventors: Robert Ibsen, Xiaohui Chen, Michael J. Cattell, Jacques V. Riodel, Thomas C. Chadwick
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Patent number: 7175700Abstract: 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: GrantFiled: July 2, 2004Date of Patent: February 13, 2007Assignee: Den-Mat CorporationInventors: Thomas C. Chadwick, Rebecca K. Santiago
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Patent number: 6824704Abstract: 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: GrantFiled: October 15, 2003Date of Patent: November 30, 2004Assignee: The Gillette CompanyInventors: Thomas C. Chadwick, Heather L. Hunt
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Patent number: 6779590Abstract: 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: GrantFiled: March 10, 2003Date of Patent: August 24, 2004Assignee: Den-Mat CorporationInventors: Rachel R. Pineda, Thomas C. Chadwick
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Publication number: 20040079920Abstract: 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: ApplicationFiled: October 15, 2003Publication date: April 29, 2004Inventors: Thomas C. Chadwick, Heather L. Hunt
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Publication number: 20030170592Abstract: 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: ApplicationFiled: March 13, 2003Publication date: September 11, 2003Inventors: Thomas C. Chadwick, Heather L. Hunt
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Publication number: 20030164230Abstract: 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: ApplicationFiled: March 10, 2003Publication date: September 4, 2003Inventors: Rachel R. Pineda, Thomas C. Chadwick
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Patent number: 6555020Abstract: 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: GrantFiled: October 28, 1999Date of Patent: April 29, 2003Assignee: Den-Mat CorporationInventors: Thomas C. Chadwick, Heather L. Hunt
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Patent number: 6551396Abstract: 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: GrantFiled: June 27, 2001Date of Patent: April 22, 2003Assignee: Den-Mat CorporationInventors: Rachel R. Pineda, Thomas C. Chadwick
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Patent number: 6511654Abstract: 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: GrantFiled: December 21, 2000Date of Patent: January 28, 2003Assignee: Den-Mat CorporationInventors: Robert Ibsen, Rachel R. Pineda, Thomas C. Chadwick, Alan Matthews
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Patent number: 6458340Abstract: 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: GrantFiled: November 12, 1999Date of Patent: October 1, 2002Assignee: Den-Mat CorporationInventors: Robert L. Ibsen, Alan Mathews, Thomas C. Chadwick, Xinyi Yu
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Publication number: 20020006386Abstract: 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: ApplicationFiled: December 21, 2000Publication date: January 17, 2002Inventors: Robert Ibsen, Rachel R. Pineda, Thomas C. Chadwick, Alan Matthews
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Patent number: 5375187Abstract: 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: GrantFiled: February 12, 1993Date of Patent: December 20, 1994Assignee: Den-Mat CorporationInventors: Robert L. Ibsen, Thomas C. Chadwick, David F. Ouellet
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Patent number: 5360770Abstract: 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: GrantFiled: January 7, 1992Date of Patent: November 1, 1994Assignee: Den-Mat CorporationInventor: Thomas C. Chadwick
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Patent number: 5009709Abstract: 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: GrantFiled: July 3, 1990Date of Patent: April 23, 1991Assignee: Den-Mat CorporationInventors: Robert L. Ibsen, Thomas C. Chadwick, Sally A. Pritchard
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Patent number: 4150233Abstract: 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: GrantFiled: May 16, 1977Date of Patent: April 17, 1979Inventor: Thomas C. Chadwick