MXPA06008414A - Dental-bleaching compositions and methods with reduced peroxide concentration - Google Patents

Abstract

A peroxide containing dual component dentifrice composition providing enhanced whitening efficacy and minimal gingival irritation and tooth sensitivity, the composition being comprised of a separately maintained first aqueous dentifrice component containing a peroxide compound and an abrasive system compatible with the peroxide and a second aqueous dentifrice component containing a desensitizing compound and an abrasive that is incompatible with peroxide compound whereby when the components are mixed and combined for the first time and exposed to the surface of teeth, an enhanced whitening effect is obtained with minimal tooth sensitivity and gum irritation.

Description

COMPOSITIONS OF DENTAL WHITENING AND METHODS WITH CONCENTRATION OF REDUCED PEROXIDE COUNTRYSIDE This application relates generally to compositions and methods for dental bleaching, and more particularly, to methods and compositions for dental bleaching based on peroxide compounds.

BACKGROUND The methods for bleaching teeth currently offered in dental practices often involve the use of bleaching kits that are carried to the home containing a paste or peroxide gel. In a type of case, the peroxide product is placed in a tray previously manufactured and used by the patient for one-two weeks in daily application for times ranging from 30 minutes to overnight. In an attempt to obtain faster bleaching, products containing high concentrations of up to 22% carbamide peroxide are now available. However, such products with high concentrations of peroxide can often cause great irritation of the teeth and gums. Therefore, there is still a continuing need for peroxide-based teeth bleaching products.

SYNTHESIS Therefore, the present inventors have succeeded in developing methods and compositions for improving teeth bleaching with peroxide compounds that accelerate the teeth whitening process, increase the bleaching activity of peroxide compounds and decrease oral irritation. . The methods and compositions are based on bleaching compositions of the teeth comprising a peroxide compound and one or more abrasive compounds, said composition having a pH of 9.0 or greater. Any one or more of an increased rate of bleaching of the teeth, of increased effectiveness of bleaching of the teeth and a decreased oral irritation are produced in comparison to those produced by a whitening composition of the teeth containing the same or a higher concentration of the teeth. compound of peroxide at a pH of 7.0 or less in the absence of 1 or more abrasive compounds. The methods may involve increasing the pH of the bleaching composition of the peroxide-containing teeth of a pH of 7.0 or less to a pH of 9.0 or more by combining, in a dual component system, a first component comprising the compound of peroxide in an aqueous vehicle at a pH of about 7 or less and adding a second component comprising an alkaline compound that produces a mixture having a pH of about 9 or greater. It is also possible to start the preparation of the composition containing both the peroxide compound and the alkaline compound so that the composition has a pH of about 9 or greater. The presence of one or more abrasive compounds further increases the effectiveness of the composition. As a result, the bleaching process is accelerated by bleaching at a lower concentration of the peroxide compound and with less oral irritation than that which is produced by a peroxide-containing composition having a pH of about 7 or less in the absence of one or more abrasive compounds.

Thus, in several embodiments, the present invention may involve a dentifrice system having a dual component comprising a first and a second component. The first component may comprise a peroxide compound and an abrasive compound compatible with peroxide. The second component may comprise an alkaline compound. The combination of the first and second components in a mixture produces a dentifrice composition having a pH of about 9 or more. By combining the first and second components it is desired that the first and second components be mixed in their entirety or that predetermined parts of the first and second components be mixed as such, for example, the first and second components can be combined in a 1: 1 ratio by either weight or volume. The pH of the first component can be in the range of from about 4 to about 7 and the pH of the second component can be in the pH range of from at least 9 to about 13. The peroxide compound in the The dentifrice composition may be at a peroxide-hydrogen equivalent concentration of not more than about 5% by weight or an equivalent peroxide-hydrogen concentration of no more than about 3.5% by weight.

In various embodiments, the present invention may also include dentifrice compositions comprising a peroxide compound and an abrasive compound compatible with peroxide. The pH of the composition may be 9.0 greater and the concentration of the peroxide compound may be at an equivalent concentration of peroxide-hydrogen of no more than about 5% by weight or an equivalent concentration of peroxide-hydrogen of no more than about of 3.5% by weight. The composition can produce a teeth whitening effect equal to or greater than that of a comparative teeth whitening composition having a hydrogen peroxide concentration of about 7% or greater by weight.

In various embodiments, the present invention may also include methods of bleaching a mammalian tooth. The methods may comprise contacting the tooth for a period of effective tooth bleaching with a tooth whitening composition. The bleaching composition of the tooth may comprise a peroxide compound and an abrasive compound compatible with the peroxide. The pH of the bleaching composition of the teeth may be at least about 9 and the peroxide compound may be at an equivalent concentration of hydrogen peroxide of not more than about 5% by weight or an equivalent concentration of peroxide of hydrogen of no more than about 3.5% by weight. In various aspects, the composition can be prepared from a dual component system comprising a first component comprising a peroxide compound and an abrasive compound compatible with peroxide and a second component comprising an alkaline compound. The contact is a period of time which is effective for whitening the tooth, for example an effective tooth whitening period, which is less than that required for a comparative composition comprising hydrogen peroxide at a concentration of about 7% by weight or greater and a pH of around 7.0 or less. Such effective tooth whitening period of the teeth whitening compositions of the present invention may not be more than about 15 minutes or not more than about 20 minutes and that of the comparative composition may be about 30 minutes. or older.

The present invention, in various embodiments, may also include methods for decreasing bleaching time, increasing the effectiveness of bleaching or decreasing oral irritation in a tooth bleaching process. The methods may comprise contacting a tooth for an effective tooth bleaching period with a teeth whitening composition comprising a peroxide compound and a peroxide compatible abrasive compound. The pH of the bleaching composition of the. teeth may be at least about 9 and the peroxide compound may be present at an equivalent concentration of hydrogen peroxide of no more than about 5% by weight or an equivalent concentration of hydrogen peroxide of no more than about 3.5% by weight. The whitening composition of the teeth produces a decrease in bleaching time, an increase in bleaching effectiveness or a decrease in oral irritation or any combination thereof as compared to a reference composition having a concentration of peroxide compound of about 7% by weight or greater and a pH of around 7.0 or less. In various aspects of incorporation, the contact may be an effective tooth bleaching period which is less than that required for a comparative composition comprising hydrogen peroxide at a concentration of about 7% by weight or more and at a pH of around 7.0 or less. For example, the effective tooth bleaching period of the teeth whitening composition may not be more than about 15 minutes or not more than about 20 minutes and that the comparative composition may be about 30 minutes or more. In several aspects of this invention, the bleaching composition of the teeth can be prepared from a dual component system comprising the first and second components in which the first component can comprise peroxide compound and a peroxide compatible abrasive compound and the second component can comprise an alkaline compound .

In several aspects of the embodiments of the present invention a dual component system is involved; the first and second components can be combined for no more than about 15 minutes, for no more than about 10 minutes, for no more than about 5 minutes or no more than about 2 minutes before the contact of a tooth with the composition to produce the bleaching of the tooth.

In several of the embodiments of the present invention, the peroxide compound can be a hydrogen peroxide, an organic peroxide compound, a compound that generates hydrogen peroxide or combinations thereof. Such an organic peroxide compound can be, for example, urea hydrogen peroxide, glyceryl peroxide, benzoyl peroxide, monoperoxy phthalate or combinations thereof. The compound that generates hydrogen peroxide can be, for example, sodium persulfate, sodium dipersulfate, sodium percarbonate, sodium perphosphate, sodium perborate, sodium persilicate, potassium persulfate, potassium dipersulfate, potassium percarbonate, perfosphate. of potassium, potassium perborate, potassium persilicate, calcium persulfate, calcium dipersulfate, calcium percarbonate, calcium phosphate, calcium perborate, calcium persilicate, sodium peroxide, potassium peroxide and calcium peroxide or combinations -, thereof.

In several of the embodiments of the present invention, the peroxide compatible abrasive comprises one or more calcium phosphate salts including, for example, calcium pyrophosphate. The peroxide compatible abrasive may be present in the teeth whitening composition or in the tooth composition at a concentration of at least about 10% by weight or at a concentration of at least about 20% by weight.

In various embodiments of the present invention, an alkaline compound may be present. Such an alkaline compound can be, for example, sodium hydroxide, potassium hydroxide, ammonium hydroxide, calcium hydroxide, magnesium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, calcium carbonate, magnesium carbonate, bicarbonate. sodium, potassium bicarbonate, baking soda, calcium bicarbonate, magnesium bicarbonate, urea, monoethanolamine, diethanolamine, triethanolamine ,. mono (iso) propanolamine, di (iso) propanolamine, tri (iso) :. propanolamine, 2-amino-2-methylpropanol, 2-amino-2-methyl-1, 3-propanediol, 2-amino-2-ethyl-l, 3-propanediol, tris (hydroxymethyl) aminomethane, N, N, N'N '-tetrakis (2-hydroxypropyl) ethylenediamine, di (2-ethylhexyl) amine, triamilamine, dodecylamine, morpholine or combinations thereof.

In several embodiments of the present invention involving a dual component system, the second component may also comprise an abrasive compound. The abrasive compound in the second component can be one or more peroxide incompatible abrasive compounds such as, for example, a silica compound or an alumina compound or one or more peroxide compatible abrasive compounds, such as, for example, one or more calcium phosphate salts including calcium pyrophosphate including calcium pyrophosphate as well as a combination of 1 or more peroxide compatible and / or incompatible peroxide-compatible abrasive compounds. The total concentration of abrasive compounds in tooth whitening compositions or dentifrice compositions may be at least 10% by weight or at least 20% by weight.

In several embodiments of the present invention involving a dual component system, the second component may also comprise a color indicator such as, for example, a group consisting of FD &C Red No. 3, FD &C Yellow No. 5, FD &C yellow No.6, FD &C green No. 3, FD &C blue No. 1 and combinations thereof. In addition, either or both of the first and second components may comprise a tooth desensitizing compound such as, for example, a potassium salt or a weak acid or a eugenol.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates the in vitro treatment of extracted human teeth for 28 for 28 treatment periods using the composition of Example 1 for 20 minute treatment periods; the comparative example Cl for 30 minute treatment periods; and comparative example C2 for 30 minute treatment.

Figure 2 illustrates the in vitro treatment of extracted human teeth for 14 or more treatments using the compositions of Example 1 for 20 minute treatment periods; the composition of Example 5 for 15 minute treatment periods; the comparative example Cl for 30 minute treatment periods; and comparative example C2 for 30 minute treatment periods.

DETAILED DESCRIPTION The present invention, in various embodiments, may involve methods and compositions for improving tooth bleaching with compositions containing 1 or more peroxide compounds and one or more abrasive compounds, wherein the compositions may have a pH of at least around 9.0. Such compositions can accelerate the whitening process of the teeth, increase the bleaching activity of the peroxide compounds and decrease oral irritation.

The reference given here to a "tooth" is intended to include the singular (tooth) and the plural (teeth). The whitening effect of the teeth of the composition is detectable by visual observation or by measurement using any of several instruments following a given application period or after successive application periods of the same duration.

The improved bleaching effect of the compositions of the present invention can be achieved at a reduced concentration of peroxide compounds compared to the concentrations normally used. The concentrations of peroxide compounds normally used may be, for example, 7.5% hydrogen peroxide by weight or 7.5% hydrogen peroxide by weight or an amount of peroxide compound other than hydrogen peroxide in which the compound of peroxide delivers a hydrogen peroxide ion or an organic peroxide ion in an amount equivalent to the hydrogen peroxide ion delivered by 7% by weight of hydrogen peroxide or 7.5% by weight of hydrogen peroxide under the same temperature conditions, exposure to light or other radiation, agitation and the like. Such equivalence is some, sometimes mentioned here as an equivalent concentration of hydrogen peroxide for a given peroxide compound. ., Thus, the concentrations of peroxide compounds as used herein refer to concentrations that deliver the amount of bleaching activity equal to that delivered by the hydrogen peroxide at the declared concentration. In the various additions, the compounds deliver an amount of peroxide ion equal to that delivered by the hydrogen peroxide at the declared concentration. For example, carbamide peroxide at a concentration of 10% by weight in an aqueous solution is generally considered to deliver the same amount of hydrogen peroxide ion as an aqueous solution of hydrogen peroxide at a concentration of about 3% by weight. weight. Thus, for the carbamide peroxide, an equivalent concentration of hydrogen peroxide of 3.5% by weight is intended to mean a concentration of carbamide peroxide of about 12 weight percent, an equivalent concentration of hydrogen peroxide of 5% by weight it is intended to mean, a carbamide peroxide concentration of about 17% by weight and an equivalent concentration of hydrogen peroxide of 7% by weight is intended to mean a carbamide peroxide concentration of about 22% by weight.

All amounts in the description and in the claims are by weight unless otherwise indicated. The reference here to the quantities by weight can also be expressed as (w / w) which is intended to mean the ratio of the number of grams of a particular component of a composition to the total number of grams of that composition.

The terms "comparative composition" and "reference composition" are used interchangeably here. The concentrations of the comparative or reference compositions as used herein are intended to mean the concentrations that deliver an amount of peroxide ion equal to that delivered by the hydrogen peroxide to the declared concentration. In several embodiments, the reference or comparative composition may be hydrogen peroxide. Other comparative compositions may, however, be used and in such cases, the concentrations of comparative compositions are intended to mean the equivalent concentrations of hydrogen peroxide of the comparative compositions. The comparative compositions may be at an equivalent concentration of hydrogen peroxide of about 3.5% by weight or greater, of about 5% by weight or greater, of about 7% by weight or greater, of about 7.5% by weight or greater, about 10% by weight or greater, or about 13% by weight or greater.

The equivalent concentrations of hydrogen peroxide of the peroxide compounds of the present invention, show an improved bleaching effect at equivalent concentrations of hydrogen peroxide of not more than 3% by weight, of not more than 3.5% by weight, of not more than 4% by weight, no more than 4.5% by weight, no more than 5% by weight, no more than 5.5% by weight, no more than 6% by weight, and no more than 6.5% by weight.

In the various embodiments of the present invention, the concentration of the peroxide compound can be seen as a reduced concentration compared to the reference composition, for example, the methods in certain embodiments, can involve a reduction in the concentration of the peroxide compound necessary to achieve the same bleaching effect in the duration of the bleaching period, effectiveness of bleaching and degree of absence of oral irritation.

The peroxide compound can be any of a variety of peroxide-based bleaching agents, which deliver a hydrogen peroxide ion or an organic peroxide ion. Such a compound includes, for example, hydrogen peroxide, organic peroxide compounds, hydrogen peroxide generating compounds, organic peroxide generating compounds and combinations thereof.

Organic peroxide compounds include, for example, hydrogen peroxide urea (carbamide peroxide), glyceryl hydrogen peroxide as well as groups of peroxides classified according to the number and class of organic functional groups attached to the oxygen atoms, such as for example , alkyl hydrogen peroxide (ROOH), dialkyl hydrogen peroxide (ROOR ') peroxyacids (RCO-0-0-H), peroxy esters (RCO-OOR'), and diacyl peroxides (R-CO-0-0) -CO-R '). Among such peroxides used in dental bleaching are diacyl peroxide, benzoyl peroxide and peroxy acid monoperoxy phthalate.

The hydrogen peroxide generating compound can be, for example, the alkali metal and alkaline earth metal persulfate, the dipersulfate, percarbonate, perphosphate, perborate and persilicate salts such as, for example, sodium persulfate, sodium dipersulfate, sodium percarbonate. , sodium perphosphate, sodium perborate, sodium persilicate, potassium persulfate, potassium dipersulfate, potassium percarbonate, potassium perphosphate, potassium perborate, potassium persilicate, calcium persulfate, calcium dipersulfate, calcium percarbonate, perphosphate of calcium, calcium perborate, calcium persilicate salts as well as sodium peroxide, potassium peroxide and calcium peroxide and combinations of all the above hydrogen peroxide generating compounds.

The improved bleaching effect is achieved at least in part due to the high pH of the bleaching composition of the teeth, which in turn is achieved by the presence of at least one alkaline compound in the composition. In dual component systems, the alkaline compound may be present in one component and the peroxide compound in the other component such that with the combination before use, the bleaching mixture of the teeth has a pH of at least around 9 or higher.

The alkaline compound may be, for example, an alkali metal, ammonium or alkaline earth metal compound such as, for example, sodium hydroxide, potassium hydroxide, ammonium hydroxide, calcium hydroxide, magnesium hydroxide, sodium carbonate. , potassium carbonate, ammonium carbonate, calcium carbonate, magnesium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, calcium bicarbonate, magnesium bicarbonate, urea, monoethanolamine, diethanolamine, triethanolamine, mono (iso) propanolamine , di (iso) propanolamine, tri (iso) ropanolamine, 2-amino-2-methylpropanol, 2-amino-2-methyl-1, 3-propanediol, 2-amino-2-ethyl-1,3-propanediol, tris (hydroxymethyl) ) aminomethane, N, N, N'N '-tetrakis (2-hydroxypropyl) ethylenediamine, di (2-ethylhexyl) amine, triamilamine, or dodecylamine, or amino ethers such as morpholine.

The alkaline compound can be at a concentration of from about 0.1% by weight to about 30% by weight, from about 0.2% by weight to about 10% by weight, from about 0.5% by weight to about of 2% by weight or from about 0.5% by weight to about 0.75% by weight.

One or more abrasive compounds may be included in the bleaching compositions of the teeth of the present invention. Such compounds impart cleaning and polishing functions to the composition. In addition to such actions, the abrasive compounds can improve the bleaching effect of the peroxide compounds.

The method for incorporating the abrasive compound into a teeth whitening composition may depend on the type of abrasive compound. For example, certain abrasive compounds can be considered incompatible with peroxide-based bleaching compounds because they tend to produce a decomposition of the peroxide compound. This can result not only in reduced efficiency, but also in a premature gas evolution resulting in swelling and / or explosion of the tubes containing the products made of a peroxide compound and an abrasive incompatible with peroxide.

Peroxide compatible abrasives, for example abrasive compounds not considered to cause substantial decomposition of the peroxide compounds, include calcium phosphate abrasive compounds (see for example, U.S. Patent No. 5,171,564, which is incorporated in its entirety by reference). Examples of such compatible peroxide abrasives include dicalcium phosphate dihydrate, anhydrous dicalcium phosphate, calcium pyrophosphate and mixtures thereof.

The abrasives incompatible with peroxide include silica compounds and alumina compounds. Such silica compounds include for example hydrated silica such as Sorbosil AC-35, marketed by INEOS Silicas, Limited (Warrington, United Kingdom, formally Crosfield Chemicals), or Zeodent 115 from Huber Company (Edison-, New Jersey). The alumina compounds may include, for example, alumina trihydrate, aluminum silicate, calcined alumina and mixtures thereof.

Other abrasives may be included in the compositions of the present invention such as, for example, hydroxyapatite, sodium metaphosphate, potassium metaphosphate, tricalcium phosphate, calcium carbonate, sodium bicarbonate, bentonite and mixtures thereof. the same.

The peroxide incompatible abrasives can be combined with the peroxide compounds immediately before use without producing a substantial composition of the peroxide compounds. Such mixtures can produce an improved bleaching activity of the peroxide compound (see, for example, U.S. Patent No. 5,766,574 which is incorporated in its entirety by reference).

Thus, in several embodiments, the bleaching compositions of the teeth of the present invention may be in the form of a dual component system. The first component may comprise the peroxide compound and the second component may comprise the alkaline compound. In certain additions, the second component may also comprise an abrasive compound incompatible with peroxide. An abrasive compound compatible with peroxide can be incorporated into either or both of the first and second components. In particular, the first component of the two component system of the present invention may comprise a peroxide compound and a calcium phosphate abrasive compound such as calcium pyrophosphate and the second component may comprise an alkaline compound. In several embodiments, the second component may also contain either or both of the abrasive compound incompatible with peroxide and the peroxide compatible abrasive compound.

The first and second components can, independently, be in the form of a liquid or a semi-solid liquid such as gel or paste.

The dual component system may be in the form of a case which includes the first and second components together with instructions for combining the first and second components and / or instructions as to the method of use of the first and second components and a mixture of them. Such instructions as those relating to the method of use may include the amount to be used, the period of time for the application of the compositions, the program for repeated and similar application.

Typically, equal amounts of the first component and the second component are combined in such a way as to effect mixing. Such mixing results in an increase in the pH of the mixture from about 9 or greater, to about 9.5 or greater or about 10 or greater, or to about 11 or greater, or to about 12 or greater or up to a pH of about of 13 or greater.

The period of time to apply the compositions of the present invention to achieve teeth whitening is sometimes mentioned herein as "a period of teeth whitening effective". This represents the period of time during which the compositions make contact with the teeth during a single application. An "effective teeth whitening period" can be about 10 minutes or less, about 15 minutes or less, about 20 minutes or less, about 25 minutes or less or about 30 minutes or less. more than about 30 minutes.

The composition for bleaching teeth can be applied in a single application or in a repeated application. Such repeated or successive application or applications may be carried out one or more times during the day such as, for example, once a day, twice a day or three times a day or less frequently, such as, for example, once every two days, once every three days, or once a week. The application period may continue, for example, for about 1 week, to about 2 weeks, to about 3 weeks, or about 4 weeks or more.

The compositions of the present invention including the bleaching compositions of the teeth and the compositions of a first and a second component of the two component systems may, in various embodiments, contain a thickening agent which imparts a high viscosity to the composition. Typically, the compositions have the viscosity of less than about 200 centipoise to about 10,000 or more, or from about 1,000 centipoise to about 9,000 centipoise or from about 4,000 to about 6,000 centipoise. In certain embodiments, the thickening agent may be a hydrophilic block copolymer of polyethylene oxide and polypropylene oxide such as a Pluronic® compound for example, Pluronic® F127 which is a trade name of BASF obtained therefrom (BASF Corporation , of Mount Olive, New Jersey). Pluronic® F127 has a molecular weight of about 4,000. This substance may be present in the compositions at a concentration of from about 5% by weight to about 10% by weight, to about 15% by weight, to about 20% by weight, to about 25% by weight, to about 30% by weight or more. In particular, the concentration of Pluronic®F127 in the first component containing the peroxide compound can be about 20% by weight, in the second component containing the alkaline compound, the concentration can be around 17% by weight and in The whitening mixture of the teeth of the two, the concentration can be around 18.5% by weight.

The high molecular weight polyethylene oxide can be used in the compositions of the present invention as thickeners. Such polyethylene oxide thickeners have a number average molecular weight, a viscosity average molecular weight, a weight average molecular weight or an average Z-molecular weight of about 50,000 to about 5,000,000. One or more of the high molecular weight polyethylene oxide may be present in a concentration range of from about 0% to about 30% by weight, from about 10% by weight to about 25% by weight or from from about 155 by weight to about 20% by weight.

One or more of glycerin, sorbitol and low molecular weight polyethylene glycol can also be included in the compositions as carrier materials which can also impart effects on viscosity. Polyethylene glycol is a nonionic polymer of ethylene oxide. The polyethylene glycol when present in the compositions of the present invention may have an average number, average weight or average molecular weight Z of from about 200 to about 1,000, from about 400 to about 800 or about 600. Glycerin, sorbitol and polyethylene glycol can each independently be present in amounts of from about 0% to about 30% by weight, from about 5% by weight to about 25% by weight, from about 10% by weight to about 20% by weight, or from about 15% by weight to about 20% by weight. Typically, glycerin and polyethylene glycol (600) are present in amounts of about 5% by weight and about 15% by weight, respectively in the first component composition, in amounts of about 5% by weight and about 10% by weight, respectively in the second component composition and in amounts of about 5% by weight and about 12.5% by weight, respectively in the teeth whitening composition.

The compositions of the present invention may also contain added water in an amount of from about 5% by weight to about 40% by weight, from about 10% by weight to about 30% by weight or from about 10% by weight. 5% by weight to around 20% by weight.

The surfactants may also be included in the compositions of the present invention as solubilizing, dispersing and / or emulsifying agents. Such surfactants may include nonionic surfactants, such as, for example, Tween 20 or anionic surfactants, such as, for example, sodium lauryl sulfate or dodecyl sodium sulfate.

The compositions of the present invention may also contain flavoring substances at a concentration of from about 0.05% by weight to about 5% by weight. Such flavor substances include, for example, an essential oil, an aldehyde extract or flavor, an ester or alcohol that imparts a peppermint, mint, pyrrhola, sassafras, clove, sage, eucalyptus, marjoram, cinnamon, lemon, lime flavor. , grapefruit, orange, apple, pear, peach, strawberry, cherry, apricot, watermelon, banana, coffee, cocoa, menthol, carbona, anethole or combinations thereof.

One or more sweetening agents may also be included in the compositions of the present invention. Such sweetening agents can include sodium saccharin, sodium cyclamate, xylitol, aspartame and the like in a concentration of from about 0.01% by weight to about 1.0% by weight.

The compositions of the present invention can also be formulated to contain one or more desensitizing agents to reduce tissue sensitivity and irritation with the application of teeth whitening compositions. Such sensitizers include, for example; the potassium salts of weak acids, such as potassium citrate, potassium chloride, potassium tertium, potassium bicarbonate, potassium oxalate, potassium nitrate as well as strontium salts and eugenol (4-allyl-2-methoxyphenol). One or more of the sensitizers may be present in the compositions of the present invention at a concentration of from about 0.05% by weight to about 0.5% by weight or from about 0.1% by weight to about 0.25% by weight for eugenol and from about 1% by weight to about 10% by weight or from about 3% by weight to about 6% by weight for potassium salts of. weak acids such as potassium nitrate.

One or more reduction and oxidation color indicators that are oxidized by hydrogen peroxide may be included in the second component of the dual component system. The color indicator may be a suitable dye to be used in a teeth whitening composition such as, for color food additives certified under the Food, Drug and Cosmetic Act to be used in food and ingested drugs, including dyes such as FD &; C red No. 3 (sodium salt of tetraiodofluorescein), FD &C yellow No. 5 (sodium salt of 4-p-sulfophenylazo-1-p-sulfophenyl-5-hydroxypyrazole-3 carboxylic acid), FD &C yellow No. 6 (sodium salt of p-sulfophenylazo-B-naphthol-6-monosulfonate), green FD &C No. 3 (disodium salt of 4- { [4- (N-ethyl-p-sulfobenzylamino) phenyl] - (4-hydroxy-2-sulfonophenyl) -methytylene.} - [l- (N-ethyl-Np-sulfobenzyl) -? - 3,5-cyclohexadienimine], FD &C Blue No. 1 (salt disodium of dibenzyldietyldiaminotriphenylcarbinol trisulfonic acid of indigotin.) The dyes change colors upon contact with the peroxide compound, thus signaling the user when the effective bleaching period is completed.The second component of the composition may contain one or more dyes at a concentration from about 0.005% by weight to about 0.5% by weight or from about 0.025% by weight to about 0.15% by weight.

Agents that remove metal ions may also be present in the compositions of the present invention. Such chelating agents include sodium acid pyrophosphate, tetraacetic acid, calcium disodium diamine, phosphoric acid, citric acid, sodium citrate, potassium citrate, sodium pyrophosphate, potassium pyrophosphate, disodium ethylenediamine tetraacetic acid and the like. The chelating agents can be incorporated into the compositions of the present invention in an amount of from about 0.1% by weight to about 8% by weight or from about 0.5% by weight to about 3.0% by weight.

Fluoride compounds having anticaries activity can also be incorporated into the compositions of the present invention. These substances release fluoride ions in an aqueous environment. Such fluoride compounds include salts such as, for example, sodium fluoride, potassium fluoride, cuprous fluoride, stannous fluoride, stannous chlorofluoride, sodium fluorosilicate, ammonium fluorosilicate, ammonium monofluorophosphate, sodium monofluorophosphate, alumina monofluorophosphate and difluorophosphate of alumina. The fluoride compounds when present may be at a sufficient concentration to release the fluoride ion in an amount of from about 15 to about 1500 ppm.

Anti-formation agents such as dimethicone may also be present in the compositions of the present invention at a concentration of from about 0% by weight to about 0.1% by weight.

The whiteness of the teeth can be observed or measured visually by any of several measuring instruments. One such instrument can be a colorimeter such as, for example, a Minolta portable Chroma meter such as CR-400 (Minolta Corporation of Ramsey, New Jersey). This colorimeter can be programmed to measure the Hunter lab values of "L", "a" and "b" in which the values "L" represent clarity and the values "a" and "b" represent coordinates of chromaticity. Lighting values "L" can represent a dark to light color in which a value of 0 represents black and a value of 100 represents white. Red to green can be expressed by the value "a", the more positive the value represented more red and the more negative the value represented more green (-80 represents green and 100 represents red). Blue to yellow can be expressed by the value "b", a more positive value represented by the yellow color in the sample (-80 represents blue and 70 represents yellow). Typically, the "L" values are used to measure the whiteness of the teeth.

The invention can also be understood with reference to the following examples.

EXAMPLE 1 This example illustrates a two-component teeth whitening system in which the concentration of the peroxide compound in the teeth whitening composition formed by combining the two components is about 3.5% by weight.

The composition of the first peroxide component and the second alkaline component is shown in Table 1.

Table 1. Teeth Whitening Composition having 3.5% H202.

A B Component Component of alkaline peroxide Ingredient Percent by weight Percent by weight Deionized water 14.3 31 Peroxide of 20 (35% of - hydrogen solution) Potassium nitrate - 6 Glycerin 5 5 Polyethylene glycol 15 10 600 Pluronic F-127 20 17 Saccharin 0.2 - Sodium hydroxide __ 0.5-0.75 FD + C yellow # 6 - 0.025-0.15 EUGENOL 0.25 - Pyrophosphate of 25 30 Calcium Sulfate of lauryl - 0.4 of sodium flavor 0.25 - Components A and B were prepared in a 'Ross mixer (from Charles Ross &Son Company of Hauppauge, - New York) as follow : Component A: Water, saccharin and 30% of the total volume of 35% hydrogen peroxide were stirred in a laboratory beaker until the saccharin dissolves. PEG 600 and glycerin were added and the mixture was placed in the Ross mixer with Pluronic F127 and stirred at high speed under vacuum until a clear gel formed (approximately 45 minutes). Calcium pyrophosphate was; added and the mixture was stirred at a medium speed by others. 10 minutes under vacuum. The remaining 70% of the peroxide volume was added and stirred for 10 minutes at an average speed; Then, the flavor was added and the mixture was stirred 5"minutes at a low speed, an extrudable paste having a pH of 6.0 was obtained.

Component B: Water, sodium hydroxide, potassium nitrate and green FD &C # 3 dye were mixed in a laboratory vessel until the potassium nitrate was dissolved. PEG 600 and glycerin were added to the aqueous phase and the mixture was placed in the Ross mixing pot together with Pluronic F127. The mixture was stirred at a higher speed under vacuum until a clear gel formed! (approximately 45 minutes). Calcium pyrophosphate, sodium lauryl sulfate, sodium bicarbonate and sodium hydroxide were added and the mixture was stirred to one. average speed for another 10 minutes under vacuum. An extrudable paste having a pH of 9.6 was obtained.

EXAMPLE 2.,! This example illustrates the bleaching effect in Vitro of example teeth whitening composition 1 which contains a peroxide compound at a concentration of 3.5% by weight and calcium pyrophosphate at a concentration of 27. 5%.

Three compositions were tested. The composition of Example 1 was prepared by mixing component A with component B in approximately equal proportions. The comparative composition designated "C" was a simple pluronic gel prepared at about the same; pH and the concentration of peroxide than the composition of example 1, but having water instead of calcium pyrophosphate. The comparative composition designated "Cl" was commercially available as a bleaching composition comprising a thickened Pluronic gel containing about 7% hydrogen peroxide at a pH of about 5.8 in addition to calcium pyrophosphate and dicalcium phosphate.

The naturally extracted stained human teeth were polished and the initial color was determined using a Minolta CR-241 chromanometer. Three teeth were submerged for 15 minutes at 37 ° C in each of the three bleaching compositions of the teeth. These 15-minute treatments were repeated 8 times for a total contact time of 2 hours. The tone of the tooth was measured in the middle and at the end of the total treatment period. The increase in whiteness of the teeth, represented as the values? E was calculated using the following formula ? E = [? L + (? A) 2 + (? B) 2 2] -11/2 Where "L", "a" and "b" are the Hunter laboratory values in which the "L" values represent clarity and the "a" and "b" values represent the chromaticity coordinates as described above. The higher values of? E indicate higher levels of whiteness of the teeth achieved. The results are shown in Table 2 given below Table 2. In Vitro Immersion Study As shown in the table, the bleaching effect of the teeth of the composition of Example 1 was greater than that of the comparative composition C at both measurement points. The comparative composition C contained 3.5% by weight of hydrogen peroxide as did the composition of example 1, however, the composition of example 1 also contained! calcium pyrophosphate at a concentration of 27.5%. This suggests that calcium pyrophosphate contributed to the bleaching effect of the teeth of the composition of Example 1. Since most of the extrinsic staining was removed from the sample teeth with pumice, the improved bleaching produced by calcium pyrophosphate is believed that results from the removal of the intrinsic tooth stain. Therefore, the data indicated above show that calcium pyrophosphate provided a beneficial bleaching benefit in addition to its effect on surface polishing and stain removal! extrinsic I This bleaching effect produced by the composition of Example 1 was greater than that produced by the comparative composition, Cl, which contained a hydrogen peroxide at a concentration of about 7% and at a pH of about 9.

EXAMPLE 3 This example illustrates the long-term in vitro effectiveness of the bleaching composition of the teeth of example 1 containing the example of peroxide at a concentration of 3.5% by weight and calcium pyrophosphate at a concentration of 27.5%.

Three compositions were tested. The composition of Example 1 was prepared by mixing component A with component B in approximately equal proportions. The designated comparative composition "Cl" was a commercially available bleaching composition composed of a thickened Pluronic gel containing about 7% hydrogen peroxide at a pH of about 5.8 in addition to calcium pyrophosphate and dicalcium phosphate. Comparative composition "C2" was a commercially available bleaching composition comprising a thickened Pluronic gel which contained about 7.5% hydrogen peroxide at a pH of about 9 and without added abrasive compounds.

Five human teeth extracted each were treated repeatedly with a comparative composition "Cl" for periods of 30 minutes per treatment; or a "C2" comparative composition for periods of 30 minutes per treatment.

Another five human extracted teeth were treated with the composition of Example 1 for periods of 20 minutes per treatment.

The study was carried out to 28 treatments, which is equivalent to 14 days of double daily treatments (a typical treatment regimen for home washing).

The shadow readings were taken at various intervals with the Minolta Stopwatch. The results are shown in Figure 1. As seen in Figure 1, the bleaching composition of the teeth of Example 1 achieved bleaching comparable to that of the comparative composition Cl at half the number of treatments compared to that of the Example 1. In addition, the composition of Example 1 achieved an example comparable to that of the comparative composition C2 which contained more than twice the level of hydrogen peroxide at a concentration of 7.5% compared to 3.5% for the composition of example 1. .

EXAMPLE 4 This example illustrates the in vivo test of the bleaching composition of the teeth of example 1 containing the peroxide compound at a concentration of 3. 5% by weight and calcium pyrophosphate at a concentration of 27.5%.

The bleaching efficacy of the composition of Example 1 was also compared to the comparative composition Cl in a two week clinical study. One cell used the comparative composition Cl for 30 minutes twice daily and the other cell used the composition of example 1 for 20 minutes once daily. The tone of the tooth was evaluated after 14 days using the shade guide Vita. The results are summarized in table 2.

Table 3: Clinical trial of composition of example 1 As shown in the table, there was no significant difference between tooth tone changes. Thus, the composition of Example 1 provides the same bleaching effect as Comparative Example Cl, but at half the level of peroxide and at one third of total use time. In addition, subjects using a comparative composition Cl reported more significant gum irritation (p = 0.038) than those using the composition of example 1.

EXAMPLE 5 This example illustrates a two-component tooth whitening system in which the concentration of the peroxide compound in the teeth whitening composition formed by the combination of the two components is about 5% by weight.

The composition of the first peroxide component and the second alkaline component is as shown in table 4.

Table 4. Whitening composition of the teeth having 5% H202.

A B Component Component of alkaline peroxide Ingredient Percent by weight Percent by weight Deionized water 24 30.2 Peroxide of 10 --hydrogen Potassium nitrate - 10 Polyox (PEG 2M) 5 - Glycerin 5 25 Polyethylene glycol 10 3 600 Xantane - 0.7 Carboxymethyl - 0.5 Cellulose Na Pluronic F-127 20 2 Saccharin sodium - 0.2 Titanium dioxide - 1 Sodium hydroxide - 1 (50%) Ti02 - 1 FD + C green # 3 - 0.025 Zeodent 115 (silica - 17.5 abrasive) Zeodent 165 __ 3 (silica thickener Baking soda - 5 sodium Pyrophosphate 25 - calcium lauryl sulfate - 0.4 sodium flavor 0.5 0.5 Components A and B were prepared as described above in example 1.

EXAMPLE 6 This example illustrates the in vitro bleaching effect of the bleaching composition of the teeth of Example 5 containing the peroxide compound at a concentration of: 5% by weight and calcium pyrophosphate at a concentration of 12.5%.

The in vitro evaluation of the stain removal by the bleaching composition of the teeth of example 5 was determined by an in vitro study method using; the human teeth extracted as described above 'in example 2. The teeth were polished with a profi paste to remove any surface stain. The root parts of 5 five teeth were placed in a row and submerged in a printing compound. To mimic live use, a tray of the sample teeth was prepared by placing a piece of tray material in a tray former and heating it until the material begins to soften. The softened tray material was then pulled down over the five teeth using a vacuum and allowed to harden to trap the teeth in the hardened tray material.

The Baseline Chromameter readings were taken from the teeth using a Minolta Chromameter CR-241. Then, small spots of the bleaching composition of the teeth of Example 5 composed of equal weight amounts of component A and B were placed, so that the peroxide content was 5% by weight, on each tooth in the tooth tray . The tray was weighed and then placed on the teeth so that a thin film of the composition of Example 5 covered each tooth. The teeth covered with tray were placed in an incubator at 37 ° C-for 15 minutes intervals and then removed, dried and measured with a Chromameter. This process was repeated for each time point. The values? E were determined for each time point as described above.

For comparison purposes, the single component peroxide paste - similar to component A alone but containing hydrogen peroxide at a concentration of 3.5% and designated "CIA" composition as described above, was evaluated for the bleaching efficiency of the teeth following the procedure of example 3 given above. The ΔE values of the teeth covered with tray were measured at 30 minute intervals for the CIA composition. For the purposes of further comparison, a professional, commercially available teeth whitening composition was also evaluated for teeth whitening efficacy with Chromameter measurements being carried out at 30 minute intervals. The commercial whitening composition as designated "C2" composition as described above was a thickened Pluronic gel which contained 7.5% peroxide to one around pH 9. No abrasives were present in the gel. The bleaching study was carried out outside of 14 treatments, which is equivalent to a typical household bleaching regimen of twice daily treatments over a period of one week. The results are shown in table 5.

Table 5: Bleaching efficiency of the teeth of the composition containing 5% H202 The results recorded in Table 5 indicate that even when the treatment time (15 minutes) using the composition of Example 5 was half the treatment time (30 minutes) of the comparative composition C2, the composition of Example 5 achieved a bleaching. faster maximum at half the number of treatments and half the application time despite the fact that the C2 composition containing 33% more peroxide bleaching agent than that of the composition of Example 5 (7.5% versus 5.0%) .

These results are further illustrated in Figure 2 which shows the comparisons above and in addition, the bleaching effects of the composition of Example 1.

Although no attempt is made to be bound by any theory, the unexpected improvement in bleaching efficiency produced by the compositions of Examples 1 and 5 compared to comparative composition C2 may be due to the presence in the composition of calcium pyrophosphate and of the silica abrasives which serve to assist in the removal of extrinsic stain and further to boost the effective peroxide concentration delivered inside the teeth by the increased density and solid content of the compositions of Examples 1 and 5 as compared with the comparative composition C2. Therefore, the higher amounts of peroxide are presumed to have been delivered by the compositions of Examples 1 and 5 to the teeth per unit weight of pulp. In addition, the peroxide ingredient in the compositions of Examples 1 and 2 is believed to have been concentrated in a water soluble part of the composition and it is believed that this concentrated part may have diffused into the teeth to remove the intrinsic stain. .

EXAMPLE 7 This example illustrates the in vivo evaluation of the bleaching efficacy of the composition of Example 5.

The composition of Example 5 was prepared by combining equal weight amounts of components A and B. The bleaching efficacy of the composition was also compared to that of comparative composition C2 in a two-week human clinical trial wherein one; Cell of 9 subjects used composition C2 thirty minutes twice daily according to the manufacturer's instructions. The other cell with 12 patients used the composition of Example 5 for 15 minutes only once daily. The tone of the teeth was evaluated after 0, 5, 7 and 14 days using a value-ordered Vita tone guide. The results are summarized in Table 6 Table 6. Effectiveness of in vivo bleaching of composition containing 5% H202 The results recorded in Table 6 indicate that the overall bleaching efficacy of the composition of Example 5 was directionally better than the comparative composition C2 and statistically better at 5 days (p = 0.025) showing a faster bleaching efficacy and • than both] application time and the number of treatments using the; The composition of Example 5 was a quarter of those of the comparative composition C2 (15 minutes once daily in., versus 30 minutes twice a day). > In addition to improving efficacy, patients in the teeth whitening study using the composition of Example 5 as described above, reported less gingival irritation and tooth sensitivity than patients using comparative composition C2. The patients involved in the study rated their sensitivity to them. teeth and gingival irritation on a scale of zero (none) to 5, the higher the number, the greater the sensitivity of the tooth and the gingival irritation experienced by the patient involved in the study. The patient rated his perception of tooth sensitivity and irritation of the gum using this scale before using the product (baseline) and after using the product for 7 days and 14 days. The patient rates gum irritation and tooth sensitivity minus the baseline ratings as recorded in Table 7 below.

Table 7. Irritation sensitivity study with the composition of example 5 * Change in the rubber irritation of the baseline. ** Close the sensitivity of the tooth from the baseline. The grades for gum irritation and the sensitivity of the teeth were lower for the composition of Example 5 compared to those of the comparative composition C2 at 7 and 14 days. The sensitivity levels of teeth reported for the composition of Examples 5 to 7 and 14 days were negative (lower than the reported baseline values), suggesting that the desensitizing agent present in the composition reduced the sensitivity of the tooth on the treatment period.

The pending application number 10 / 065,244 - filed on September 27, 2002 is incorporated in its entirety by reference.

The description of this invention is merely exemplary in nature and therefore variations that do not depart from the essence of the invention are intended to be within the scope of said invention. Such variations should not be seen as a departure from the spirit and scope of the invention.

Claims (93)

R E I V I N D I C A C I O N S

1. A dual-component toothpaste system comprising a first component comprising a peroxide compound and an abrasive compound compatible with the peroxide and a second component comprising an alkaline compound, wherein with the combination of the first and second components, is produced a dentifrice composition having a pH of about 9.0 or greater.

2. The system as claimed in clause 1, characterized in that the first component has a pH of from about 4 to about 7 and the second component has a pH of from about 9 to about 13.

3. The system as claimed in clause 1, characterized in that the peroxide compound is selected from the group consisting of hydrogen peroxide, an organic peroxide compound, a hydrogen peroxide generating compound and combinations thereof.

4. The system as claimed in clause 1, characterized in that the peroxide compound is an organic peroxide compound selected from the group consisting of hydrogen peroxide urea, glyceryl peroxide, benzoyl peroxide, monoperoxy phthalate and combinations thereof.

5. The system as claimed in clause 1, characterized in that the peroxide compound is a hydrogen peroxide that generates a compound selected from the group consisting of sodium persulfate, sodium dipersulfate, sodium percarbonate, sodium perphosphate, perborate sodium, sodium persilicate, potassium persulfate, potassium dipersulfate, potassium percarbonate, potassium perphosphate, potassium perborate, potassium persilicate, calcium persulfate, calcium dipersulfate, calcium percarbonate, calcium perphosphate, calcium perborate , calcium persilicate, sodium peroxide, potassium peroxide and calcium peroxide or combinations thereof.

6. The system as claimed in clause 1, characterized in that with the combination of the first and second components the peroxide compound is present in the dentifrice composition at an equivalent concentration of hydrogen peroxide of no more than about 5.0%.

7. The system as claimed in clause 6, characterized in that with the combination of the first and second components the peroxide compound is present in the dentifrice composition at an equivalent concentration of hydrogen peroxide of no more than about 3.5% by weight.

8. The system as claimed in clause 1, characterized in that the peroxide compatible abrasive comprises one or more calcium phosphate salts.

9. The system as claimed in clause 8, characterized in that the peroxide compatible abrasive comprises calcium pyrophosphate.

10. The system as claimed in clause 1, characterized in that by combining the first and second components, the peroxide compatible abrasive is present in the dentifrice composition at a concentration of at least about 10% by weight.

11. The system as claimed in clause 10, characterized in that combining the first and second components, the peroxide compatible abrasive is present in the dentifrice composition at a concentration of at least about 20% by weight.

12. The system as claimed in clause 1, characterized in that the alkaline compound is an alkali metal hydroxide or an alkali metal carbonate salt.

13. The system as claimed in clause 1, characterized in that the alkaline compound is selected from the group consisting of sodium hydroxide, potassium hydroxide, ammonium hydroxide, calcium hydroxide, magnesium hydroxide, sodium carbonate, carbonate of potassium, ammonium carbonate, calcium carbonate, magnesium carbonate, sodium bicarbonate, potassium bicarbonate, baking soda, calcium bicarbonate, magnesium bicarbonate, urea, monoethanolamine, diethanolamine, triethanolamine, mono (iso) propanolamine, di (iso) propanolamine, tri (iso) propanolamine, 2-amino-2-methylpropanol, 2-amino-2-methyl-1, 3-propanediol, 2-amino-2-ethyl-l, 3-propanediol, tris (hydroxymethyl) aminomethane , N, N, N'N '-tetrakis (2-hydroxypropyl) ethylenediamine, di (2-ethylhexyl) amine, triamilamine, dodecylamine, morpholine or combinations thereof.

14. The system as claimed in clause 1, characterized in that the second component also comprises a second abrasive compound.

15. The system as claimed in clause 14, characterized in that the second component comprises a peroxide-incompatible abrasive compound.

16. The system as claimed in clause 15, characterized in that the abrasive compound incompatible with peroxide is a silica compound or an alumina compound.

17. The system as claimed in clause 14, characterized in that the second abrasive compound comprises one or more calcium phosphate salts.

18. The system as claimed in clause 17, characterized in that the second abrasive compound comprises calcium pyrophosphate.

1 . The system as claimed in clause 14, characterized in that by combining the first and second components, the total concentration of abrasive compounds in the dentifrice composition is at least about 20% or greater.

20. The system as claimed in clause 1, characterized in that the second component also comprises a color indicator.

21. The system as claimed in clause 20, characterized in that the color indicator is selected from the group consisting of FD &C red No. 3, FD &C yellow No. 5, FD &C yellow No.6, FD &; C green No. 3, FD &C blue No. 1 and combinations thereof.

22. The system as claimed in clause 1, characterized in that either or both of the first and second components further comprise a tooth desensitizing compound.

23. The system as claimed in clause 22, characterized in that the tooth desensitizing compound is a potassium salt or a weak acid or a eugenol.

24. A dentifrice composition comprising a peroxide compound at an equivalent peroxide concentration of no more than about 5.0% by weight and a peroxide compatible abrasive compound, wherein the composition has a pH of about 9.0 or greater.

25. A composition as claimed in clause 24, characterized in that the peroxide compound is at an equivalent concentration of hydrogen peroxide of no more than about 3.5% by weight.

26. A composition as claimed in clause 24 or 25, characterized in that the composition produces a whitening effect of the teeth equal to or greater than that of the teeth whitening composition compared having a hydrogen peroxide concentration of 7% by weight or older.

27. A composition as claimed in clause 24 or 25, characterized in that the peroxide compound is selected from the group consisting of hydrogen peroxide, a hydrogen peroxide compound, a hydrogen peroxide generating compound and combinations thereof .

28. A composition as claimed in clause 27, characterized in that the peroxide compound is an organic peroxide compound selected from the group consisting of urea hydrogen peroxide, glyceryl peroxide, benzoyl peroxide, monoperoxy phthalate and combinations thereof .

29. A composition as claimed in clause 27, characterized in that the peroxide compound is a hydrogen peroxide generating compound selected from the group consisting of sodium persulfate, sodium dipersulfate, sodium percarbonate, sodium perphosphate, sodium perborate, sodium, sodium persilicate, potassium persulfate, potassium dipersulfate, potassium percarbonate, potassium perphosphate, potassium perborate, potassium persilicate, calcium persulfate, calcium dipersulfate, calcium percarbonate, calcium perphosphate, calcium perborate, calcium persilicate, sodium peroxide, potassium peroxide and calcium peroxide or combinations thereof.

30. A composition as claimed in clause 24 or 25, characterized in that the peroxide compatible abrasive comprises one or more of the calcium phosphate salts.

31. A composition as claimed in clause 30, characterized in that the peroxide compatible abrasive comprises calcium pyrophosphate.

32. A composition as claimed in clause 24 or 25, characterized in that the peroxide-compatible abrasive is present in the dentifrice composition at a concentration of at least about 10% by weight.

33. A composition as claimed in clause 32, characterized in that the peroxide compatible abrasive is present in the dentifrice composition at a concentration of at least about 20% by weight.

34. A composition as claimed in clause 24 or 25, characterized in that the composition comprises an alkaline compound which is an alkali metal hydroxide or an alkali metal carbonate salt.

35. A composition as claimed in clause 24 or 25, characterized in that the composition comprises an alkaline compound selected from the group consisting of sodium hydroxide, potassium hydroxide, ammonium hydroxide, calcium hydroxide, magnesium hydroxide, carbonate sodium, potassium carbonate, ammonium carbonate, calcium carbonate, magnesium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, calcium bicarbonate, magnesium bicarbonate, urea ,. monoethanolamine, diethanolamine, triethanolamine, mono (iso). propanolamine, di (iso) propanolamine, tri (iso) propanolamine, 2-amino-2-methylpropanol, 2-amino-2-methyl-1, 3-propanediol, 2-amino-2-ethyl-l, 3-propanediol, tris ( hydroxymethyl) aminomethane, N, N, N'N '-tetrakis (2-hydroxypropyl) ethylenediamine, di (2-ethylhexyl) amine, triamilamine, dodecylamine, morpholine or combinations thereof.

36. A composition as claimed in clause 24 or 25, characterized in that it comprises an abrasive which is a silica compound or an alumina compound.

37. A composition as claimed in clause 36, characterized in that the total concentration of abrasive compounds is at least about 20% by weight.

38. A composition as claimed in clause 24 or 25, characterized in that said composition is a whitening composition of the teeth which is prepared no more than 15 minutes before application to the teeth.

39. A composition as claimed in clause 38, characterized in that it comprises a color indicator.

40. A composition as claimed in clause 39, characterized in that the color indicator is selected from the group consisting of FD &C red No. 3, FD &C yellow No. 5, FD &C yellow No. 6, FD &; C green No. 3, FD &C blue No. 1 and combinations thereof.

41. A composition as claimed in clause 24 or 25, characterized in that it also comprises a tooth desensitizing compound.

42. A composition as claimed in clause 41, characterized in that the tooth desensitizing compound is a potassium salt of a weak acid or eugenol.

43. A method for whitening teeth in a mammal, the method comprises contacting the tooth for an effective tooth bleaching period with a teeth whitening composition comprising a peroxide compound at an equivalent concentration of hydrogen peroxide no greater than about 5% by weight and an abrasive compound compatible with peroxide, said composition! having a pH of at least about 6.

44. A method as claimed in clause 43, characterized in that the peroxide compound is at an equivalent concentration of hydrogen peroxide of no more than about 3.5% by weight.

45. A method as claimed in clause 43 or 44, characterized in that the composition is prepared from a dual component system comprising comprising a first component comprising a peroxide compound and an abrasive compound compatible with peroxide and a second component which comprises an alkaline compound.

46. A method as claimed in clause 45, characterized in that the composition is prepared no more than 15 minutes before said contact.

47. A method as claimed in clause 43 or 44, characterized in that the contact is for an effective teeth whitening period which is less than that required for a comparative composition comprising hydrogen peroxide at a concentration of 7% or greater by weight and at a pH of 7.0 or less.

48. A method as claimed in clause 47, characterized in that the effective teeth whitening period of the teeth whitening composition is not more than about 20 minutes and that of the comparative composition is about 30 minutes or higher.

49. A method as claimed in clause 43 or 44, characterized in that the peroxide compound is selected from the group consisting of hydrogen peroxide, an organic peroxide compound, a hydrogen peroxide generating compound and combinations thereof.

50. A method as claimed in clause 49, characterized in that the peroxide compound is an organic peroxide compound selected from the group consisting of urea hydrogen peroxide, glyceryl peroxide, benzoyl peroxide, monoperoxy phthalate and combinations thereof .

51. A method as claimed in clause 49, characterized in that the peroxide compound is a hydrogen peroxide generating compound selected from the group consisting of sodium persulfate, sodium dipersulfate, sodium percarbonate, sodium perphosphate, sodium perborate, sodium, sodium persilicate, potassium persulfate, potassium dipersulfate, potassium percarbonate, potassium perphosphate, potassium perborate, potassium persilicate, calcium persulfate, calcium dipersulfate, calcium percarbonate, calcium perphosphate, calcium perborate, calcium persilicate, sodium peroxide, potassium peroxide and calcium peroxide or combinations thereof.

52. A method as claimed in clause 43 or 44, characterized in that the peroxide compatible abrasive comprises one or more of the calcium phosphate salts.

53. A method as claimed in clause 52, characterized in that the peroxide compatible abrasive comprises calcium pyrophosphate.

54. A method as claimed in clause 43 or 44, characterized in that the peroxide-compatible abrasive is present in the dentifrice composition at a concentration of at least about 10% by weight.

55. A method as claimed in clause 54, characterized in that the peroxide-compatible abrasive is present in the dentifrice composition at a concentration of at least about 20% by weight.

56. A method as claimed in clause 45, characterized in that the alkaline compound is an alkali metal hydroxide or an alkali metal carbonate salt.

57. A method as claimed in clause 45, characterized in that the alkaline compound is selected from the group consisting of sodium hydroxide, potassium hydroxide, ammonium hydroxide, calcium hydroxide, magnesium hydroxide, sodium carbonate, carbonate potassium, ammonium carbonate, calcium carbonate, magnesium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, calcium bicarbonate, magnesium bicarbonate, urea, monoethanolamine, diethanolamine, triethanolamine, mono (iso) propanolamine, di ( iso) propanolamine, tri (iso) propanolamine, 2-amino-2-methylpropanol, 2-amino-2-methyl-1, 3-propanediol, 2-amino-2-ethyl-l, 3-propanediol, tris (hydroxymethyl) aminomethane, N, N, N'N '-tetrakis (2-hydroxypropyl) ethylenediamine, di (2-ethylhexyl) amine, triamilamin, dodecylamine, morpholine or combinations thereof.

58. A method as claimed in clause 45, characterized in that the second component of the two component system further comprises a second abrasive compound.

59. A method as claimed in clause 58, characterized in that the second abrasive compound is an abrasive compound incompatible with peroxide.

60. A method as claimed in clause 59, characterized in that the abrasive compound incompatible with peroxide comprises a silica compound or an alumina compound.

61. A method as claimed in clause 58, characterized in that the second abrasive compound comprises one or more calcium phosphate salts.

62. A method as claimed in clause 61, characterized in that the one or more calcium phosphate salts comprise calcium pyrophosphate.

63. A method as claimed in clause 58, characterized in that the whitening composition of the teeth has a total concentration of abrasive compounds in the dentifrice composition which is at least about 20% by weight.

64. A method as claimed in clause 45, characterized in that the second component further comprises a color indicator.

65. A method as claimed in clause 64, characterized in that the color indicator is selected from the group consisting of FD &C red No. 3, FD &C yellow No. 5, FD &C yellow No.6, FD &; C green No. 3, FD &C blue No. 1 and combinations thereof.

66. A method as claimed in clause 45, characterized in that either or both of the first and second components further comprises a tooth desensitizing compound.

67. A method as claimed in clause 66, characterized in that the tooth desensitizing compound is a potassium salt of a weak acid or of a eugenol.

68. A method for decreasing the whitening time, increasing the effectiveness of bleaching or decreasing oral irritation in a teeth whitening process, the method comprises contacting a tooth for an effective tooth bleaching period with a whitening composition of the teeth comprising a peroxide compound at an equivalent concentration of hydrogen peroxide of no more than about 5% by weight and a peroxide compatible abrasive compound, said bleaching composition of the teeth having a pH of at least about 9.0

69. A method as claimed in clause 68, characterized in that the bleaching composition of the teeth comprises the peroxide compound at a concentration of no more than about 3.5%.

70. A method as claimed in clause 68 or 69, characterized in that the whitening composition of the teeth produces a decrease in the whitening time, an increase in the effectiveness of bleaching or a decrease in the oral irritation or any combination of the same as compared to a reference composition having a peroxide compound concentration of about 7% by weight or more and a pH of 7.0 or less. •

71. A method as claimed in clause 68 or 69, characterized in that the whitening composition of the teeth is prepared from a dual component system comprising a first dual component comprising a first component comprising a peroxide compound and a compound abrasive compatible with peroxide and a second component comprising an alkaline compound.

72. A method as claimed in clause 71, characterized in that the whitening composition of the teeth is prepared no more than 15 minutes before contact.

73. A method as claimed in clause 68 or 69, characterized in that the contact is by effective tooth whitening period which is less than that required for a comparative composition comprising hydrogen peroxide at a concentration of 7% by weight. weight or greater and at a pH of 7.0 or less.

74. A method as claimed in clause 73, characterized in that the effective teeth whitening period of the teeth whitening composition is not more than about 20 minutes and that of a comparative composition is about 30 minutes or higher.

75. A method as claimed in clause 68 or 69, characterized in that the peroxide compound is selected from the group consisting of hydrogen peroxide, an organic peroxide compound, a hydrogen peroxide generating compound and combinations thereof.

76. A method as claimed in clause 75, characterized in that the peroxide compound is an organic peroxide compound selected from the group consisting of urea hydrogen peroxide, glyceryl peroxide, benzoyl peroxide, monoperoxy phthalate and combinations thereof .

77. A method as claimed in clause 75, characterized in that the peroxide compound is a hydrogen peroxide generating compound selected from the group consisting of sodium persulfate, sodium dipersulfate, sodium percarbonate, sodium perphosphate, sodium perborate, sodium, sodium persilicate, • potassium persulfate, potassium dipersulfate, potassium percarbonate, potassium perphosphate, potassium perborate, potassium persilicate, calcium persulfate, calcium dipersulfate, calcium percarbonate, calcium perphosphate, calcium perborate , calcium persilicate, sodium peroxide, potassium peroxide and calcium peroxide or combinations thereof.

78. A method as claimed in clause 68 or 69, characterized in that the peroxide compatible abrasive comprises one or more of the calcium phosphate salts.

79. A method as claimed in clause 78, characterized in that the one or more calcium phosphate salts comprise calcium pyrophosphate.

80. A method as claimed in clause 68 or '69, characterized in that the peroxide compatible abrasive is present in the bleaching composition of the teeth at a concentration of at least about 10% by weight.

81. A method as claimed in clause 80, characterized in that the peroxide compatible abrasive is present in the bleaching composition of the teeth at a concentration of at least about 20% by weight.

82. A method as claimed in clause 71, characterized in that the alkaline compound is an alkali metal hydroxide or an alkali metal carbonate salt.

83. A method as claimed in clause 71, characterized in that the alkaline compound is an alkaline compound selected from the group consisting of sodium hydroxide, potassium hydroxide, ammonium hydroxide, calcium hydroxide, magnesium hydroxide, sodium carbonate , potassium carbonate, ammonium carbonate, calcium carbonate, magnesium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, calcium bicarbonate, magnesium bicarbonate, urea, monoethanolamine, diethanolamine, triethanolamine, mono (iso) propanolamine , di (iso) propanolamine, tri (iso) propanolamine, 2-amino-2-methylpropanol, 2-amino-2-methyl-1,3-propanediol, 2-amino-2-ethyl-l, 3-propanediol, tris (hydroxymethyl) ) aminomethane, N, N, N'N '-tetrakis (2-hydroxypropyl) ethylenediamine, di (2-ethylhexyl) amine, triamilamine, dodecylamine, morpholine or combinations thereof.

84. A method as claimed in clause 71, characterized in that the second component of the two component system further comprises a second abrasive compound.

85. A method as claimed in clause 84, characterized in that the second abrasive compound comprises an abrasive compound incompatible with peroxide.

86. A method as claimed in clause 85, characterized in that the abrasive incompatible with peroxide comprises a silica compound or an alumina compound.

87. A method as claimed in clause 84, characterized in that the second abrasive compound comprises one or more calcium phosphate salts.

88. A method as claimed in clause 87, characterized in that the one or more calcium phosphate salts comprise calcium pyrophosphate.

89. A method as claimed in clause 84, characterized in that the whitening composition of the teeth has a total concentration of abrasive components in the dentifrice composition which is at least about 20% by weight.

90. A method as claimed in clause 71, characterized in that the second component further comprises a color indicator.

91. A method as claimed in clause 90, characterized in that the color indicator is selected from the group consisting of FD &C red No. 3, FD &C yellow No. 5, FD &C yellow No.6 , FD &C Green No. 3, FD &C Blue No. 1 and combinations thereof.

92. A method as claimed in clause 71, characterized in that either or both of the first or second components further comprise a tooth desensitizing compound.

93. A method as claimed in clause 92, characterized in that the tooth desensitizing compound is a potassium salt of a weak acid or a eugenol. SUMMARY A peroxide-containing dual component dentifrice composition provides improved bleaching efficacy and minimal gum irritation and sensitivity of the teeth, the composition being composed of a first component of separately maintained aqueous dentifrice containing a peroxide compound and a system abrasive compatible with peroxide 'and a second component of aqueous dentifrice containing a desensitizing compound and an abrasive that is incompatible with the peroxide compound so that when the components are mixed and combined for the first time and exposed to the surface of the teeth , an improved bleaching effect is obtained with minimal tooth sensitivity and gum irritation.