Surface-reacted calcium carbonate for desensitizing teeth

Abstract

The present invention relates to surface-reacted calcium carbonate, wherein the surface-reacted calcium carbonate is a reaction product of natural or synthetic calcium carbonate with carbon dioxide and at least one acid. Said calcium carbonate 5 and oral compositions containing the same can be used as a medicament, and especially in treating dentine hypersensitivity.

What is claimed is: 
     
         1 . An oral care composition comprising:
 a surface-reacted calcium carbonate that is a reaction product of natural or synthetic calcium carbonate with carbon dioxide and at least one acid and that is in the form of particles having a volume median grain diameter (d 50 ) of equal to or less than 3 μm and a volume determined top cut particle size (d 98 ) of equal to or less than 6 μm;   wherein the at least one acid is chosen from hydrochloric acid, sulphuric acid, sulphurous acid, phosphoric acid, citric acid, oxalic acid, acetic acid formic acid, and mixtures thereof.   
     
     
         2 . The oral care composition of  claim 1 , wherein contacting of teeth with the oral care composition is effective to treat dentine hypersensitivity. 
     
     
         3 . The oral care composition of  claim 1 , wherein the oral care composition comprises from 1 to 20 wt.-% of the surface-reacted calcium carbonate, based on the total weight of the composition. 
     
     
         4 . The oral care composition of  claim 1 , wherein the oral care composition is a toothpaste, a toothpowder, or a mouthwash. 
     
     
         5 . The oral care composition of  claim 1 , wherein the oral care comprises at least one active agent associated with the surface-reacted calcium carbonate. 
     
     
         6 . The oral care composition of  claim 1 , wherein the oral care composition comprises at least one additional desensitizing agent chosen from potassium nitrate, glutaraldehyde, silver nitrate, zinc chloride, strontium chloride hexahydrate, sodium fluoride, stannous fluoride, strontium chloride, strontium acetate, arginine, hydroxyapatite, calcium sodium phosphosilicate, potassium oxalate, calcium phosphate, calcium carbonate, bioactive glass, and mixtures thereof. 
     
     
         7 . The oral care composition of  claim 1 , wherein the oral care composition comprises a bioadhesive polymer chosen from hydroxyethyl methacrylate, PEG/PPG copolymers, polyvinylmethylether/maleic anhydride copolymers, polyvinylpyrrolidone (PVP), cross-linked PVP, shellac, polyethylene oxide, methacrylates, acrylate copolymers, methacrylic copolymers, vinylpyrrolidone/vinyl acetate copolymers, polyvinyl caprolactam, polylactides, silicone resins, silicone adhesives, chitosan, milk proteins (casein), amelogenin, ester gum, and combinations thereof. 
     
     
         8 . The oral care composition of  claim 1 , wherein the surface-reacted calcium carbonate has a radioactive dentine abrasion (RDA) value of less than 70. 
     
     
         9 . The oral care composition of  claim 1 , wherein the surface-reacted calcium carbonate has a radioactive dentine abrasion (RDA) value of less than 50. 
     
     
         10 . The oral care composition of  claim 1 , wherein the oral care composition has a pH between 7.5 and 10. 
     
     
         11 . The oral care composition of  claim 1 , wherein the at least one acid is phosphoric acid. 
     
     
         12 . The oral care composition of  claim 1 , wherein the surface-reacted calcium carbonate particles have a volume median grain diameter (d 50 ) of from 1.5 to 2.9 μm and/or a volume determined top cut particle size (d 98 ) of from 3.5 to 5.5 μm. 
     
     
         13 . The oral care composition of  claim 1 , wherein the surface-reacted calcium carbonate particles have a volume median grain diameter (d 50 ) of from 2.2 to 2.6 μm and/or a volume determined top cut particle size (d 98 ) of from 4.5 to 5 μm. 
     
     
         14 . The oral care composition of  claim 1 , wherein the surface-reacted calcium carbonate particles have a specific surface area of from 5 m 2 /g to 200 m 2 /g, measured using nitrogen and the BET method of ISO 9277. 
     
     
         15 . The oral care composition of  claim 1 , wherein the surface-reacted calcium carbonate particles have a specific surface area of from 30 m 2 /g to 60 m 2 /g, measured using nitrogen and the BET method of ISO 9277. 
     
     
         16 . The oral care composition of  claim 1 , wherein the carbon dioxide is formed in situ by the treatment with the at least one acid and/or is supplied from an external source. 
     
     
         17 . The oral care composition of  claim 1 , wherein the carbon dioxide is formed in situ by the treatment with the at least one acid. 
     
     
         18 . The oral care composition of  claim 1 , wherein the molar ratio of the at least one acid to the natural or synthetic calcium carbonate is from 0.5 to 4. 
     
     
         19 . The oral care composition of  claim 1 , wherein the surface-reacted calcium carbonate is a reaction product of the natural calcium carbonate with the carbon dioxide and the at least one acid in an aqueous suspension. 
     
     
         20 . An oral care composition comprising:
 a surface-reacted calcium carbonate that is a reaction product of natural calcium carbonate with carbon dioxide and phosphoric acid, wherein the molar ratio of the phosphoric acid to the natural calcium carbonate is from 0.5 to 4, and that is in the form of particles having a volume median grain diameter (d 50 ) of from 1.5 to 2.9 μm and a volume determined top cut particle size (d 98 ) of from 3.5 to 5.5 μm;   wherein the carbon dioxide is formed in situ by the phosphoric acid treatment, and contacting of teeth with the oral care composition is effective to treat dentine hypersensitivity.