Drug – bio-affecting and body treating compositions – Dentifrices
Reexamination Certificate
2000-11-08
2002-09-10
Rose, Shep K. (Department: 1614)
Drug, bio-affecting and body treating compositions
Dentifrices
Reexamination Certificate
active
06447756
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a desensitizing dentifrice composition which eliminates or reduces the discomfort and pain associated with dentinal hypersensitivity and more particularly to a two-component desensitizing dental composition containing potassium salt desensitizing agents.
2. The Prior Art
Dentinal hypersensitivity is defined as acute, localized tooth pain in response to physical stimulation of the dentine surface as by thermal (hot or cold) osmotic, tactile combination of thermal, osmotic and tactile stimulation of the exposed dentin.
Exposure of the dentine, which is generally due to recession of the gums, or loss of enamel, frequently leads to hypersensitivity. The art has determined that dentine tubules open to the surface have a high correlation with dentine hypersensitivity, Abs, J. Clin. Periodontal. 14,280-4 (1987). Dentinal tubules lead from the pulp to the cementum. When the surface cementum of the tooth root is eroded, the dentinal tubules become exposed to the external environment. The exposed dentinal tubules provide a pathway for transmission of fluid flow to the pulpal nerves, the transmission induced by changes in temperature, pressure and ionic gradients.
It is known to the art that potassium ion releasable compounds are effective in the treatment of dentinal hypersensitivity. For example, U.S. Pat. No. 3,863,006 discloses that toothpastes containing potassium salts such as potassium nitrate desensitize the teeth after tooth brushing for several weeks. It is believed by those skilled in the art that an elevation in the extracellular potassium concentration in the vicinity of pulpal nerves underlying sensitive dentin is responsible for the therapeutic desensitizing effect of topically applied oral products which contain potassium nitrate. Due to passive diffusion of potassium ion into and out of the open dentine tubules, repeated application of the active ingredient is necessary to build up the necessary concentration in the vicinity of the pulpal nerves.
It is believed that the improved pain relief is obtained from the use of potassium salts in combination with gradual mineralization on the dentin surface which can either totally or partially occlude dentin tubules. Total occlusion will dramatically reduce fluid flow within the tubules which stimulates pain. Partial occlusion of the dentin tubules is believed to increase delivery of potassium ion inside the tooth because the inward diffusive flux is less dependent upon tubule radius than outward fluid flow (due to positive pulpal pressures) (See DH Pashley and WG Mathews, Archs. Oral Biol. (1993) 38, 577-582). Therefore, this enhanced delivery of potassium should enhance relief.
In copending application U.S. Ser. No. 09/234,829 filed Jan. 21, 1999 there is disclosed a dual component dentifrice comprised of separately housed dentifrice components of acidic and alkaline pH, at least one component containing a potassium salt, the components being combined during use, the combined composition exhibiting improved effectiveness, when applied to the teeth, in obturating dentinal tubules with concomitant desensitization of teeth as compared to single component compositions of neutral pH.
Although the dentifrice composition of U.S. Ser. No. 09/234,829 is highly effective in the treatment of dentine hypersensitivity, the art continuously seeks means to improve the efficacy of such treatment.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided a method for the treatment of dentinal hypersensitivity using a multicomponent dentifrice comprised of two separately housed, semi-solid aqueous components; the first component containing, in an orally acceptable vehicle having an alkaline pH of at least about 8.5, and preferably about 9.0 to about 10.5, and containing an alkali metal silicate salt and a potassium ion releasable compound, the second component having an acid pH from about 2 to about 6 and preferably about 3 to about 5, whereby upon mixing and combination of the components, upon repeated application of the mixture to the teeth increased relief from dentinal hypersensitivity is experienced by the user.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In use, the components of the two component dentifrice of the present invention comprises a first alkaline dentifrice component containing the potassium ion releasable salt and an alkali metal silicate salt, and a second acidic dentifrice component containing a polymeric polycarboxylate compound. Both components are preferably formulated to have similar rheological characteristics, so that the two components may be simultaneously coextruded in the desired predetermined amounts when separately housed in a multicompartmented tube or pump device.
To prepare the alkaline dentifrice component of the present invention, an alkaline agent is generally incorporated in the dentifrice component which normally includes a vehicle which contains water, humectant, surfactant and an abrasive. The pH of such dentifrice is in the alkaline range of about 8.5 to 10.5 and preferably about 9.0 to about 10.0. The acidic dentifrice component is prepared using a similar vehicle, the pH of such dentifrice being in the acid range of about 2 to about 6.0 and preferably about 3 to about 5.0.
The humectant used in the preparation of the dentifrice components is generally a mixture of humectants, such as glycerol, sorbitol and a polyethylene glycol of molecular weight in the range of 200 to 1000, but other mixtures of humectants and single humectants may also be employed. The humectant content is in the range about of 10% to about 80% by weight and preferably about 20 to about 50% by weight of the dentifrice component. The water content is in the range of about 10 to about 40% by weight and preferably about 20 to about 30% by weight.
Surfactants may be incorporated in the dentifrice components to provide foaming properties. The surface-active material is preferably anionic or nonionic in nature. Suitable examples of anionic surfactants are higher alkyl sulfates such as potassium or sodium lauryl sulfate which is preferred, higher fatty acid monoglyceride monosulfates, such as the salt of the monosulfated monoglyceride of hydrogenated coconut oil fatty acids, alkyl aryl sulfonates such as sodium dodecyl benzene sulfonate, higher fatty sulfoacetates, higher fatty acid esters of 1,2 dihydroxy propane sulfonate.
The surface active agent is generally present in the dentifrice component compositions of the present invention at a concentration of about 0.5 to about 10.0% by weight and preferably about 1.0 to about 5.0% by weight.
Abrasives may be incorporated in the dentifrice components of the present invention and preferred abrasives are siliceous materials, such as silica. A preferred silica is a precipitated amorphous hydrated silica, such as Sorbosil AC-35, marketed by Crosfield Chemicals, or Zeodent 115 from Huber Company but other abrasives may also be employed, including hydroxyapatite, sodium metaphosphate, potassium metaphosphate, tricalcium phosphate, calcium phosphate dihydrate, anhydrous dicalcium phosphate, calcium pyrophosphate, magnesium orthophosphate, trimagnesium phosphate, calcium carbonate, sodium bicarbonate, alumina trihydrate, aluminum silicate, calcined alumina and bentonite.
The concentration of abrasive in the dentifrice component compositions of the present invention will normally be in the range of 2 to about 40% by weight and preferably 5 to 25% by weight.
Inorganic and organic thickeners are also used in the preparation of the dentifrice components. Inorganic thickeners which may be included in the dentifrice components include amorphous silicas such as Zeodent 165 available from Huber Corporation, and Sylox 15 from W. R. Grace.
Organic thickeners of natural and synthetic gums and colloids may also be used to prepare the dentifrice components of the present invention. Examples of such thickeners are carrageenan (Irish moss), xanthan gum, sodium carboxymethyl cellulose, starch, polyvinylp
Dixit Nagaraj
Gambogi Robert J.
Pillay Kowsilla P.
Colgate - Palmolive Company
Rose Shep K.
Shapiro Paul
LandOfFree
Desensitizing dual component dentifrice does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Desensitizing dual component dentifrice, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Desensitizing dual component dentifrice will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2873911