composition

Abstract

A film forming oral care composition used to treat the surface of at least one tooth wherein the composition comprises; a tubule blocking agent comprising a bioactive glass, wherein the tubule blocking agent has a particle size less than 10 µm, and wherein the composition is a leave on composition, and wherein the composition is free of one or more of, an abrasive, an opacifier, a fluoride, and / or surfactant.

Description

[0001] 70230W001

[0002] COMPOSITION

[0003] BACKGROUND

[0004] The present invention relates to a composition and a method of using a composition for tooth remineralisation and / or desensitization. More particularly, the present invention relates to a composition comprising a bioactive glass and a water soluble polymer and a method of using such a composition for tooth remineralisation and / or desensitization.

[0005] BACKGROUND OF THE INVENTION

[0006] It is well known that tooth structure comprises an inner dentine layer and an outer hard enamel layer that serves to protect the tooth. The enamel layer is composed of dense calcium hydroxyapatite mineral crystals; in the form of large "prismatic enamel" crystals surrounded by smaller crystals that fill in the "inter-prismatic" spaces.

[0007] The formula of calcium hydroxy apatite is nominally Cas(PO4)3OH. The dentine however is composed of both hydroxy apatite, as well as structural proteins that result in a much softer and less dense structure than enamel and which is much easier to damage. The dentine structure also consists of pores or "tubules" which create openings from the tooth surface that run down into the pulp cavity of the tooth where the tooth nerve is located.

[0008] Normally this softer porous dentine structure is covered by the denser enamel layer, or by the soft gingival tissue, which protects the nerve from outside stimuli. Tooth hypersensitivity is associated with the exposure of these tubules, through loss of the protective enamel layer or recession of the gums, that tends to increase with age.

[0009] The recession of the gums can also be caused by overbrushing, as well as periodontal disease. The loss of enamel can occur as a result of acid erosion from acidic foods or cariogenic bacteria and abrasion from over brushing or other mechanical effects. Orthodontic brace wearers are also especially susceptible to loss of tooth enamel, leading to white spot lesions. 70230W001

[0010] Demineralisation of tooth enamel tends to reveal tubules. Dentinal tubules are naturally present in the enamel and they provide for an osmotic flow of liquid between the inner pulp region of the tooth and the outer root surfaces. However, when demineralisation of the enamel layer occurs, these tubules tend to become exposed. When heat, cold, or pressure are applied, fluids tend to gain direct access to the tooth nerve causing pain. It is possible to alleviate this condition by coating the teeth with varnishes, lacquers etc., but this tends to be a short term remedy, since the lacquers become quickly worn away.

[0011] Bioactive glasses, alone or incorporated into oral care compositions, are known to remineralise teeth. When applied to the teeth they have the effect of rebuilding the hydroxy apatite structure. For example, US Patents 6,338,751 and 6,086,374, relate to oral care products which comprise remineralisation compositions (typically comprising calcium, phosphorous, silica and sodium ions in the form of a bioactive glass). The bioactive glass incorporated into these products releases remineralising ions onto the tooth’s surface and helps occlude the open tubules, reducing tooth sensitivity, and rebuilding the enamel layer. However, a disadvantage of these compositions is that the contact time for toothpastes or dentifrices is limited to the time of brushing and so may only be a minute or two.

[0012] Accordingly, there is a desire for oral care compositions, that are alleviating dentinal (hyper) sensitivity for a user.

[0013] STATEMENT OF INVENTION

[0014] According to the invention there is provided a film forming oral care composition used to treat the surface of at least one tooth wherein the composition comprises; a tubule blocking agent comprising a bioactive glass, wherein the tubule blocking agent has a particle size less than 10 pm and wherein the composition is a leave on composition, and wherein the composition is free of one or more of:- abrasive, opacifier, 70230W001 fluoride, and I or surfactant.

[0015] The invention may also comprise the use of the composition to clean teeth. Ideally the composition is applied manually (i.e. not with a toothbrush). Preferred forms of manual application include manual application using a finger or thumb to rub the composition onto a tooth or gum surface. Once applicated in this way further spreading may be aided by lingual movement and I or movement of saliva within the mouth.

[0016] Preferably, however, the composition is a “leave-on” composition. As such it is intended for being left on teeth for (as an example) at least 4 hours. Ideally it is intended to be left on teeth overnight.

[0017] By this it is intended that a user applies the composition to a tooth surface at, or just before, the user retires to sleep. Sleep is understood to usually occur (for the longest period) at night; although it is appreciated that this is not always the case. Here of course it is realised that there is no fixed time in which users retire to sleep and that this is influenced by a number of factors including age and responsibilities (such as employment). However, it is understood that retirement to sleep will generally be understood to comprise a period of approximately about 4 hours to about 10 hours; and may be longer or shorter depending on an individual user’s circumstances. In this way the composition is able to act on the tooth surface whilst the user sleeps.

[0018] Accordingly, according to a further aspect of the invention, there is provided a composition according to the invention for use in the treatment of dentine hypersensitivity, and / or for use in occluding dentine tubules.

[0019] According to a further aspect of the invention, there is provided a method of treating dentine hypersensitivity or a method of occluding dentine tubules, wherein the method comprises applying a composition according to the invention to the teeth of a subject.

[0020] Preferably, the use or method comprises applying the composition to a surface of the teeth of a subject and leaving the composition in contact with the surface for at least 4 70230W001 hours; preferably at least 6 hours; more preferably, at least 8 hours; and most preferably, over night.

[0021] The composition may then be (at least partially) actively or passively removed when the user awakens. This removal may be in a teeth cleaning operation. Alternatively I additionally, the removal may occur by eating and I or drinking, such as at breakfast.

[0022] Without wishing to be bound by theory it is postulated that the composition of the present invention is capable of forming a (thin) film round a surface (such as a dental surface) to which it is applied. As such, generally speaking, the present invention may reside in the provision of a remineralisation composition comprising a bioactive glass in the form of a thin film, which may be adhered to at least one tooth, and provides a convenient and unobtrusive method of generating a high and sustained local concentration of remineralising and / or desensitizing components on a tooth surface.

[0023] The composition is free of at least one or more of abrasives, opacifiers, fluoride and surfactants.

[0024] Preferably the composition is free of abrasive. Preferably the composition is free of opacifier. Preferably the composition is free of fluoride. Preferably the composition is free of surfactant.

[0025] Most preferably the composition is free of abrasive, opacifier, fluoride, and surfactant.

[0026] As used herein the term “free of” means less than 0.1 % by weight, and preferably less than 0.05% by weight of the component.

[0027] As used herein the term "oral care composition" includes any composition for treating all, or a portion of, the oral cavity of an individual.

[0028] The present inventors have discovered that the composition of the invention provides excellent sensitivity protection; allowing users to whiten teeth / dentures with confidence. 70230W001

[0029] In more detail it has been found that the composition of the invention, by reducing the particle size of the tubule blocking agent increased the reactivity of same. This is associated with greater reactivity and faster apatite formation (in, for example, the first 24 hours).

[0030] It had no significant effect on the mechanical or crystallographic properties of the HA- like surface layer formed by the dentifrice (even after, for example, 5 days of development). This has been found to be associated with no change in hardness or reduced modulus and no change in crystallite size.

[0031] It has been found to result in greater tubule occlusion and greater penetration of material deeper into the tubules (even after, for example, only 24 and 48 hours).

[0032] DETAILED DESCRIPTION OF THE INVENTION

[0033] Tubule Blocking Agent Particle Size

[0034] The tubule blocking agent preferably has a particle size of less than about 10 pm.

[0035] Preferably the tubule blocking agent has a particle size less than about 9 pm, more preferably less than about 8 pm, more preferably less than about than 7 pm, more preferably less than about 6 pm, more preferably less than about 5 pm, more preferably less than about 4 pm, more preferably less than about 3 pm, more preferably less than about 2.5 pm, more preferably less than about 2.25 pm, more preferably less than about 2.1 pm, more preferably less than about 2 pm.

[0036] Alternatively and I or additionally the tubule blocking agent preferably has an average particle size in the range of about 0.01 to about 10 pm, more preferably in the range of about 0.01 to about 9 pm, more preferably in the range of about 0.01 to about 8 pm, more preferably in the range of about 0.01 to about 7 pm, more preferably in the range of about 0.01 to about 6 pm, more preferably in the range of about 0.01 to about 5 pm, more preferably in the range of about 0.01 to about 4 pm, more preferably in the range of about 0.01 to about 3 pm, more preferably in the range of about 0.01 to about 2.5 70230W001 pm, more preferably in the range of about 0.01 to about 2.25 pm, more preferably in the range of about 0.01 to about 2.1 pm, more preferably in the range of about 0.01 to about 2 pm. In each of these ranges the lower amount (about 0.01 pm) may be replaced by about 0.1 pm, about 0.2 pm, about 0.3 pm, about 0.4 pm, about 0.5 pm, about 0.6 pm, about 0.7 pm, about 0.8 pm, about 0.9 pm, about 1.0 pm, 1.1 pm, about 1 .2 pm, about 1 .3 pm, about 1 .4 pm, about 1 .5 pm, about 1 .6 pm, about 1 .7 pm, about 1.8 pm, or about 1.9 pm (wherein the tubule blocking agent has a particle size less than 10 pm).

[0037] Alternatively and I or additionally the tubule blocking agent preferably has a particle size in the range of about 0.01 to about 10 pm, more preferably in the range of about 0.01 to about 9 pm, more preferably in the range of about 0.01 to about 8 pm, more preferably in the range of about 0.01 to about 7 pm, more preferably in the range of about 0.01 to about 6 pm, more preferably in the range of about 0.01 to about 5 pm, more preferably in the range of about 0.01 to about 4 pm, more preferably in the range of about 0.01 to about 3 pm, more preferably in the range of about 0.01 to about 2.5 pm, more preferably in the range of about 0.01 to about 2.25 pm, more preferably in the range of about 0.01 to about 2.1 pm, more preferably in the range of about 0.01 to about 2 pm. In each of these ranges the lower amount (about 0.01 pm) may be replaced by about 0.1 pm, about 0.2 pm, about 0.3 pm, about 0.4 pm, about 0.5 pm, about 0.6 pm, about 0.7 pm, about 0.8 pm, about 0.9 pm, about 1.0 pm, 1.1 pm, about 1 .2 pm, about 1 .3 pm, about 1 .4 pm, about 1 .5 pm, about 1 .6 pm, about 1 .7 pm, about 1 .8 pm, or about 1 .9 pm.

[0038] It has surprisingly been found that where the bioactive glass has an average particle size of less than 4 pm, improved treatment of dentine hypersensitivity and occlusion of tubules is observed when compared to compositions comprising larger particle size bioactive glass. This is even more the case with even smaller average particle sizes such as those in the range of less than 3 pm. 70230W001

[0039] Accordingly, preferably, the tubule blocking agent comprises a bioactive glass with an average particle size in the range of from 0.5 pm to 4 pm; more preferably from 0.5 pm to 3 pm; and most preferably from 1 pm to 2.5 pm.

[0040] Particle size measurements are carried out by laser diffraction according to standard techniques.

[0041] Preferably, the average particle sizes are determined as a D50 value according to ISO 13320:2020. D50 is the median particle diameter corresponding to the 50thpercentile of the cumulative undersize distribution by volume.

[0042] Amount of Tubule Blocking Agent

[0043] Preferably the tubule blocking agent is present in an amount of 0.1 to 20 percent by weight of the composition. The tubule blocking agent may be present in an amount of 1 to 19 percent, 2 to 18 percent, 3 to 17 percent, 4 to 16 percent, about 5 to about 15 percent, by weight of the composition.

[0044] Nature of Tubule Blocking Agent

[0045] The tubule blocking agent includes a bioactive glass.

[0046] Typically, the bioactive glass has a composition comprising; from 40% to 96% by weight of SiC>2, from 0% to 35% by weight of sodium oxide Na2O, from 4% to 46% by weight of calcium oxide CaO, and from 1 % to 15% by weight of P2O5. Preferably, the bioactive glass has a composition comprising; from 40% to 60% by weight of SiC>2, from 5% to 30% by weight of sodium oxide Na2O, from 10% to 35% by weight of calcium oxide CaO, and from 1 % to 12% by weight of P2O5.

[0047] A suitable example of a bioactive glass consists of 45 percent by weight silicon dioxide, 24.5 percent by weight sodium oxide, 6 percent by weight phosphorus oxide, and 24.5 percent by weight calcium oxide. (45 wt% SiO2, 24.5 wt% CaO, 24.5 wt% Na2O, and 6.0 wt% P2O5) This bioactive glass is available commercially under the trade name, NOVAMIN, also known as 45S5 BIOGLASS. 70230W001

[0048] Another alternate tubule blocking agent may be present in addition to the bioactive glass.

[0049] The alternate tubule blocking agent is preferably selected from the list comprising silica, colloidal silica, nano zinc oxide, sub-micron alumina and sub-micron polymer beads, or mixtures thereof.

[0050] Where present the alternate tubule blocking agent preferably has a similar size to the bioactive glass.

[0051] Anti-sensitivity

[0052] An additional desensitizing agent, including a tubule blocking agent or a nerve desensitizing agent and mixtures thereof, for example as described in WO 02 / 15809 (Block) is included in a composition according to the invention.

[0053] Preferably the additional desensitizing agent is present in an amount of 0.1 and 5 percent by weight of the composition.

[0054] The desensitizing agent may comprise a strontium salt such as strontium chloride, strontium acetate or strontium nitrate or a potassium salt such as potassium citrate, potassium chloride, potassium bicarbonate, potassium gluconate and especially potassium nitrate.

[0055] Diluent

[0056] Preferably, the composition comprises less than 5% by weight of water; and more preferably less than 2% by weight of water. Most preferably, the composition is an anhydrous composition. It is highly preferred that the composition is free of water since water can react with and degrade the bioactive glass present in the formulation. Whilst it is known that water and bioactive glasses negatively interact, it has been found by the present inventors that this is a particular problem in the compositions of the invention due to the small size of the bioactive glasses present therein. The small 70230W001 particle size increases the reactivity of the bioactive glasses meaning that it is even more important that the dentifrices have a low water content to avoid the undesirable reaction of the water and bioactive glass.

[0057] Preferably the dentifrice comprises a single phase non-aqueous composition comprising at least one solvent or diluent.

[0058] Preferably, the dentifrice comprises one or more diluents in a total amount of at least 50% by weight of the composition; preferably at least 60% by weight of the composition; and more preferably at least 75% by weight of the composition.

[0059] The diluent preferably provides a film-forming ability (see above).

[0060] Preferably, the one or more diluents comprise one or more polyols, one or more polyalkylene glycols, or a combination thereof. More preferably, the one or more diluents comprise glycerol, polyethylene glycol, or a combination thereof. Most preferably, the one or more diluents comprise glycerol and polyethylene glycol.

[0061] It has been found by the present inventors that it is particularly difficult to provide adequate thickness to compositions of the invention. This is due to the low water contents of the compositions. Typically, aqueous compositions are thickened by interaction of water with one or more polymers that thicken aqueous systems such as xanthan gum. With very low water contents, it has been found hard by the inventors to provide a dentifrice formulation with adequate thickness. Without being limited by theory, it has been found by the present invention that having compositions of a suitable thickness is advantageous for achieving the benefits underlying the present invention including achieving effective dentine tubule occlusion with the bioactive glass particles. Without being limited by theory, thickened compositions may be applied more easily to the teeth and have greater film forming ability. They may also stay in place for longer periods of time thus providing time for the bioactive glass to effectively block dentine tubules. This is harder to achieve with less viscous / less thick compositions.

[0062] It has been found by the present inventors that compositions of the invention can be suitably thickened by the inclusion of one or more polyalkylene glycol diluents in the formulation. Accordingly, preferably, the one or more polyalkylene glycols are present 70230W001 in an amount of at least 10% by weight of the composition and more preferably at least 15% by weight. Most preferably, the compositions of the invention comprise one or more polyalkylene glycols in an amount of from 15% to 30% by weight such as from 15% to 25% by weight or from 18% to 25% by weight of the composition. Accordingly, the compositions of the invention preferably comprise polyethylene glycol in an amount of at least 10% by weight and more preferably at least 15% by weight of the composition. Most preferably, the compositions of the invention comprise polyethylene glycol in an amount of from 15% to 30% by weight such as from 15% to 25% by weight or from 18% to 25% by weight of the composition.

[0063] The compositions of the invention typically comprises glycerine. Glycerine is also known as glycerol and glycerin. The terms may be used interchangeably in this specification.

[0064] It is well known that commercially available glycerine may contain between 0.1 -2.0 percent by weight of water which is in association with the glycerine. Typically, this amount is < 0.5 percent and for example between 0.1 - 0.5 percent by weight of the glycerine. This small amount of water is bound to the glycerine and is therefore not available to the other ingredients. The skilled person would still consider a composition containing glycerine as being non-aqueous.

[0065] Preferably the at least one solvent or diluent comprises up to 95 percent by weight of the final composition. Preferably the amount of glycerol is up to 80 percent by weight of the final composition; most preferably about 75 percent by weight. Preferably the amount of polyethylene glycol (PEG) is up to 25 percent by weight of the final composition; most preferably about 20 percent by weight.

[0066] Gel

[0067] The non-aqueous dentifrice composition according to the invention comprise a supporting (or gelling) polymer to solidify the solvent and actives. This is particularly preferred in order to provide a dentifrice with a desirably thick viscosity as discussed above. 70230W001

[0068] Thus, typically, the compositions of the invention comprise one or more thickening polymers. Preferably, the one or more thickening polymers are present in a total amount of at least 0.5% by weight of the composition; and more preferably, a total amount of from 0.5% to 3% by weight of the composition.

[0069] The skilled person will be aware of many different types of supporting polymer for dentifrice use. Two non-limiting examples include a copolymer of a methyl vinyl ether and a maleic anhydride, such as Gantrez(R), and polyacrylic acid homopolymers, often referred to as Carbomers. Hydroxyethyl cellulose is another alternative.

[0070] Accordingly, preferably, the one or more thickening polymers comprise carbomer, hydroxyethylcellulose, a copolymer of a methyl vinyl ether and maleic anhydride, a copolymer of a methyl vinyl ether and maleic acid, or a combination thereof.

[0071] More preferably, the one or more thickening polymers comprise a carboxyvinyl polymer such as a carbomer. It has been found by the present inventors that carbomers are particularly good at providing dentifrice compositions with a desirable thickness which as discussed above is believed important for achieving the advantages of the present invention.

[0072] A carbomer comprises synthetic high molecular-weight cross-linked polymers of acrylic acid. The polymer chains formed of repeating units of acrylic acid may be cross-linked with, for example: allyl sucrose to provide a carbomer available commercially in one form as Carbopol™ 934; ethers of pentaerythritol to provide a carbomer available commercially in one form as Carbopol™ 974; or with divinyl glycol, available commercially in one form as Noveon™ AA-1. Carbopol™ polymers are manufactured by B.F. Goodrich Company.

[0073] In one embodiment the carboxyvinyl polymer comprises Carbopol™ 974.

[0074] The carboxyvinyl polymer may be present in the range of from about 0.1 to about 7.5 percent by weight of the non-aqueous composition. In one embodiment the carboxyvinyl polymer is present in an amount from about 0.2 to about 1.0 percent by weight of the composition. 70230W001

[0075] Abrasive

[0076] The compositions of the present invention are preferably free of abrasive.

[0077] Compositions of the present invention are preferably not used to clean teeth and therefore would not need an abrasive component.

[0078] However, an abrasive can be added if required. Any abrasive known for use in oral care compositions may be used in conjunction with the composition of the present invention.

[0079] Abrasives are common ingredients in regular toothpastes. An abrasive is usually required to aid the removal of detritus from the teeth, dentures and I or remainder of the oral cavity being cleaned. Clearly it will be appreciated that a degree of abrasiveness is required I advantageous in the removal of said detritus., However, it will also be appreciated that excessive abrasiveness can be equally detrimental: excessive wear on dental materials can be problematic. As such it will be appreciated that the use of an abrasive is a compromise of achieving adequate detritus removal without causing excessive / undesired wear on dental materials.

[0080] Suitable abrasives for use in compositions include, for example, amorphous, gelled, precipitated or fumed silica, zinc orthophosphate, sodium bicarbonate (baking soda), plastic particles, alumina, hydrated alumina, calcium carbonate, calcium pyrophosphate, insoluble metaphosphates or mixtures thereof.

[0081] The silica abrasive may be a natural amorphous silica, for instance diatomaceous earth; or a synthetic amorphous silica such as a precipitated silica. By way of example, silica abrasives include those marketed under the following trade names Zeodent, Sident, Sorbosil or Tixosil by Huber, Degussa, Ineos and Rhodia respectively.

[0082] The silica abrasive may be a spherical, anhydrous, amorphous, silica gel particles having a pore volume of less than 0.1 ml / g (as described in co-pending European Application Number 18782931.2). This abrasive preferably comprises non-fused 70230W001 spherical, anhydrous, amorphous, silica gel particles obtainable by a process that involves precipitation followed by calcination to remove water to produce a dense particulate silica material, and wherein said silica gel particles comprise: a. a pore volume from 0.03 ml / g to less than 0.1 ml / g; b. a mean particle size from 1 micro to 10 micro; c. a BET surface area of 50 m2 / g or less; d. an oil absorption capacity of 20 to 50 m 1 / 100 g; and e. a water content of less than 0.2 weight percent.

[0083] Such silica gel particles have been found to effectively clean, polish and remove stains from the surface of teeth or dentures without a high degree of abrasion thereby reducing scratching and damage to the tooth or denture surface. Such compositions thereby provide superior cleaning, polishing, gentle stain removal and whitening of tooth surfaces or dentures.

[0084] Silica gel particles for use in the invention are available commercially from Asahi Glass Si-Tech. Co., Ltd., 13-1 , Kitaminatomachi„Wakamatsu-ku, Fukuoka, 808-0027, Japan, and are sold under the brand name Sunspherc(a), for example Sunsphere NP-30 and Sunsphcrc NP-100. A CAS1for some types of silica gel particles of use in the invention is 7631 -86-9.

[0085] Sunsphere(a) silica gel particles are derived from sodium silicate and contain no crystalline silica. They consist of spherical particles of almost identical size which do not cohere, and which provide a smooth texture.

[0086] Similar silica gel particles are available from Madhu Silica PVT. LTD under the brand name ( as an example) of MFIL-GS.

[0087] Suitably an abrasive is present in an amount up to 5 percent by weight of the total composition, for example from 0.1 to 4 percent by weight, for example from 0.1 to 3 percent, for example from 0.1 to 2 percent, for example from 0.1 to 1.5 percent, for example from 0.2 to 1 percent, for example from 0.25 to 1 percent by weight of the total composition. 70230W001

[0088] Generally, an amount of abrasive suitable for use in dentifrice composition of the present invention will be empirically determined to provide an acceptable level of cleaning and polishing, in accordance with the techniques well known in the art.

[0089] Fluoride

[0090] The dentifrice compositions of the present invention are preferably free of fluoride.

[0091] By this it is meant that the compositions comprise less than 0.05 wt% of a fluoride source.

[0092] Thickening agent

[0093] The compositions of the present invention may comprise a thickening agent to achieve a desirable viscosity. Any thickening agent known in the art for oral care compositions may be used.

[0094] A non-limiting example is thickening silica. This has little or no abrasive characteristics.

[0095] Suitable examples of a thickening silica are available commercially for example as Sident 22S or Syloid 244FP.

[0096] In one embodiment the thickening silica is present in the range of from about 0 to about 5.0 % by weight of the non-aqueous composition.

[0097] Surfactant

[0098] The dentifrice compositions of the present invention are preferably free of surfactant.

[0099] By this it is meant that the compositions comprise less than 0.05 wt% of a surfactant source.

[0100] Other 70230W001

[0101] Compositions of the present invention may contain additional formulating agents such as flavouring agents, sweetening agents, opacifying or colouring agents and preservatives, selected from those conventionally used in an oral hygiene composition art for such purposes.

[0102] In general, the optional agents may be used in a minor amount or proportion of the overall formulation. By way of example, such components are usually present in from about 0.001 to about 5 percent by weight of the non-aqueous composition. In total such components may range from 0.1 to 25 percent by weight of the composition.

[0103] The composition typically has a viscosity suitable for application to the oral cavity. The viscosity will vary depending on the type of composition made and the ultimate use thereof. One of skill in the art can readily prepare compositions with suitable viscosities for use in the oral cavity from the teachings provided herein.

[0104] The compositions according to the present invention may be prepared by admixing the ingredients in the appropriate relative amounts in any order that is convenient.

[0105] A composition according to the present invention may be mildly acidic, neutral or mildly alkaline i.e. has a slurry pH in the range from 6.0 to 7.5, for example from pH 6.1 to 7.4, 6.2 to 7.3, or 6.2 to 7.2. In one embodiment the composition has a pH of about 6.2. In a further embodiment the composition has a pH of about 7.0. The pH referred to is that measured when the composition is slurried with water in a 1 :3 weight ratio of the composition to water. Suitably the slurry is prepared by slurring the composition with water in a weight ratio of one part composition and three parts distilled water. The pH is determined using a standard pH meter. 70230W001

[0106] Examples

[0107] The following formulae representing the invention were prepared:-

[0108] Results

[0109] All of the formulas above demonstrated successful tubule occlusion when applied to teeth in in vitro testing.

Claims

70230W001CLAIMS1 . Afilm forming oral care composition suitable to treat the surface of at least one tooth, wherein the composition comprises; a tubule blocking agent comprising a bioactive glass, wherein the tubule blocking agent has a particle size less than 10 pm and wherein the composition is a leave on composition. and wherein the composition is free of one or more of:- an abrasive, an opacifier, a fluoride, and I or a surfactant.

2. The composition according to claim 1 , wherein the tubule blocking agent has a particle size less than about 9 pm, more preferably less than about 8 pm, more preferably less than about than 7 pm, more preferably less than about 6 pm, more preferably less than about 5 pm, more preferably less than about 4 pm, more preferably less than about 3 pm, more preferably less than about 2.5 pm, more preferably less than about 2.25 pm, more preferably less than about 2.1 pm, more preferably less than about 2 pm.

3. The composition according to claim 1 , wherein the tubule blocking agent has a particle size in the range of about 0.01 to about 10 pm, more preferably in the range of about 0.01 to about 9 pm, more preferably in the range of about 0.01 to about 8 pm, more preferably in the range of about 0.01 to about 7 pm, more preferably in the range of about 0.01 to about 6 pm, more preferably in the range of about 0.01 to about 5 pm, more preferably in the range of about 0.01 to about 4 pm, more preferably in the range of about 0.01 to about 3 pm, more preferably in the range of about 0.01 to about 2.5 pm, more preferably in the range of about 0.01 to about 2.25 pm. more preferably in the range of about 0.01 to about 2.1 pm, more preferably in the range of about 0.01 to about 2 pm.70230W0014. The composition according to claim 3, wherein in each of these ranges the lower amount (about 0.01 pm) may be replaced by about 0.1 pm, about 0.2 pm, about 0.3 pm, about 0.4 pm, about 0.5 pm, about 0.6 pm, about 0.7 pm, about 0.8 pm, about 0.9 pm, about 1.0 pm, 1.1 pm, about 1.2 pm, about 1.3 pm, about 1.4 pm, about 1.5 pm, about 1 .6 pm, about 1.7 pm, about 1 .8 pm, or about 1 .9 pm.

5. A composition according to any preceding claim, wherein the tubule blocking agent comprises a bioactive glass with an average particle size in the range of from 0.5 pm to 4 pm; preferably from 0.5 pm to 3 pm; and more preferably from 1 pm to 2.5 pm.

6. The composition according to any of the preceding claims, wherein the tubule blocking agent is present in an amount of 0.1 to 20 percent by weight of the composition.

7. A composition according to any preceding claim, wherein the bioactive glass has a composition comprising; from 40% to 96% by weight of SiC>2, from 0% to 35% by weight of sodium oxide Na2O, from 4% to 46% by weight of calcium oxide CaO, and from 1 % to 15% by weight of P2O5, preferably, from 40% to 60% by weight of SiC>2, from 5% to 30% by weight of sodium oxide Na2O, from 10% to 35% by weight of calcium oxide CaO, and from 1 % to 12% by weight of P2O5.

8. A composition according to any preceding claim, wherein the composition comprises one or more solvents or one or more diluents; preferably, wherein the one or more diluents or one or more solvents are present in a total amount of at least 50% by weight of the composition; preferably at least 60% by weight of the composition; and more preferably at least 75% by weight of the composition.

9. A composition according to any preceding claim, wherein the one or more diluents comprise one or more polyols, one or more polyalkylene glycols, or a combination thereof; preferably, wherein the one or more diluents comprise glycerol, polyethylene glycol, or a combination thereof; more preferably wherein the one or more diluents comprise glycerol and polyethylene glycol.70230W00110. A composition according to any preceding claim, wherein the composition comprises one or more polyalkylene glycols in a total amount of at least 15% by weight of the composition; preferably, wherein the composition comprises polyethylene glycol in an amount of at least 15% by weight of the composition.

11. A composition according to any preceding claim, wherein the dentifrice comprises one or more thickening polymers; preferably, wherein the one or more thickening polymers are present in a total amount of at least 0.5% by weight of the composition; more preferably, wherein the one or more thickening polymers are present in a total amount of from 0.5% to 3% by weight of the composition.

12. A composition according to Claim 11 , wherein the one or more thickening polymers comprise carbomer, hydroxyethylcellulose, or a combination thereof.

13. A composition according to any preceding claim, wherein the composition comprises less than 5% by weight of water; preferably less than 2% by weight of water; more preferably wherein the composition is an anhydrous composition.

14. The composition according to any of the preceding claims, wherein the composition comprises a single phase non-aqueous composition comprising at least one solvent.

15. The composition according to claim 14, wherein the at least one solvent comprises up to 85 percent by weight of the final composition.

16. The composition according to any of the preceding claims, wherein the composition is free of abrasive.

17. The composition according to any of the preceding claims, wherein the composition is free of opacifier.

18. The composition according to any of the preceding claims, wherein the composition is free of fluoride.70230W00119. The composition according to any of the preceding claims, wherein the composition is free of surfactant.

20. A composition according to any preceding claim, for use in the treatment of dentine hypersensitivity, and / or for use in occluding dentine tubules.21 . A method of treating dentine hypersensitivity or a method of occluding dentine tubules, wherein the method comprises applying a composition according to any one or more of Claims 1 to 19 to the teeth of a subject.

22. A composition for use according to Claim 20, or a method according to Claim 21 , wherein the use or method comprises applying the composition to a surface of the teeth of a subject and leaving the composition in contact with the surface for at least 4 hours; preferably at least 6 hours; more preferably, at least 8 hours; and most preferably, over night.

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