Oral composition

Abstract

To provide an oral composition having excellent acid resistance improving action, lasting suppressive effect on hypersensitivity-like symptoms, and excellent usability.SOLUTION: An oral composition comprises: component (A) sodium fluoride; component (B) a water-soluble calcium salt; component (C) at least one selected from the group consisting of pyrophosphoric acid and alkali metal salts thereof; and component (D) at least one selected from the group consisting of water-soluble aluminum salts and water-soluble potassium salts (excluding pyrophosphate salts).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an oral composition.

Background Art

[0002] The dentin of the root surface exposed due to gingival recession has lower acid resistance than enamel and tends to have a faster progression of dental caries. In addition, in teeth with an exposed root surface, it is not uncommon for hypersensitivity-like symptoms to occur.

[0003] Conventionally, as an active ingredient for preventing dental caries, fluorides such as sodium fluoride have been widely used. In addition, Patent Document 1 has proposed a dentifrice composition containing one or more selected from tripolyphosphate and pyrophosphate, a water-soluble calcium salt, sodium fluoride, and cationized cellulose.

[0004] On the other hand, water-soluble aluminum salts and water-soluble potassium salts have been used for hypersensitivity-like symptoms. In addition, Patent Document 2 has proposed an oral composition containing potassium nitrate, a linear water-soluble polyphosphate, and a polyhydric alcohol.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the conventional technology, the effect of improving the acid resistance of dentin is not sufficient. In recent years, with the aging of the population and the increase in the number of remaining teeth in the elderly, the number of root surface caries occurring on the gingivally recessed root surface has increased, and further improvement in the acid resistance improvement effect is required. Regarding hypersensitivity-like symptoms, the prior art has insufficient persistence of the inhibitory effect on hypersensitivity-like symptoms. Furthermore, there are also problems in terms of usability, such as experiencing an unpleasant taste or irritation after using the oral composition and insufficient fragrance intensity of the fragrance.

[0007] An object of the present invention is to provide an oral composition excellent in acid resistance improvement effect, persistence of inhibitory effect on hypersensitivity-like symptoms, and usability.

Means for Solving the Problems

[0008] As a result of intensive studies, the present inventors have found that by combining sodium fluoride, a water-soluble calcium salt, pyrophosphoric acid or its alkali metal salt, and a water-soluble aluminum salt or a water-soluble potassium salt (excluding pyrophosphates), the acid resistance improvement effect is synergistically enhanced, and it is also excellent in the persistence of the inhibitory effect on hypersensitivity-like symptoms and usability. The present invention is based on the above findings and has the following aspects.

[0009] <1> (A) component: sodium fluoride and, (B) component: a water-soluble calcium salt, and, (C) component: at least one selected from the group consisting of pyrophosphoric acid and its alkali metal salts, and, (D) component: at least one selected from the group consisting of a water-soluble aluminum salt and a water-soluble potassium salt (excluding pyrophosphates), and, An oral composition containing. <2> The oral composition according to <1>, wherein the (B) component is at least one selected from the group consisting of calcium chloride, calcium glycerophosphate, calcium gluconate, calcium lactate, and calcium pantothenate. <3> The oral composition according to <1> or <2>, wherein the (C) component is at least one selected from the group consisting of pyrophosphoric acid, sodium pyrophosphate, and potassium pyrophosphate. <4> The oral composition according to any one of <1> to <3>, wherein the component (D) is at least one selected from the group consisting of aluminum lactate and potassium nitrate. <5> The oral composition according to any one of <1> to <4>, wherein the molar ratio of the component (B) to the component (D) is 0.001 to 15.0. <6> The oral composition according to any one of <1> to <5>, wherein the total amount of aluminum ions and potassium ions in the oral composition is 0.01 to 5% by mass based on the total mass of the oral composition. <7> The oral composition according to any one of <1> to <6>, which is a dentifrice abrasive.

Advantages of the Invention

[0010] According to the present invention, it is possible to provide an oral composition having an excellent acid resistance improvement effect, a persistent effect of suppressing hypersensitivity-like symptoms, and a good usability.

Modes for Carrying Out the Invention

[0011] In this specification, the “oral composition” means a composition mainly intended for use in the oral cavity. “Water-soluble” means that the solubility in water at 20°C is 1 g / 100 g or more. “~” indicating a numerical range means that the numerical values described before and after it are included as the lower limit value and the upper limit value.

[0012] 〔Oral Composition〕 The oral composition of the present invention contains a component (A), a component (B), a component (C), and a component (D).

[0013] <(Component A)> (Component A) is sodium fluoride (NaF). By containing the component (A) in the oral composition, fluoride ions are supplied into the oral cavity, and the acid resistance improvement effect of the dentin of the tooth root surface is exhibited. (Component A) can be a commercially available product.

[0014] <Component (B)> Component (B) is a water-soluble calcium salt. When the oral composition contains Component (B), calcium ions are supplied into the oral cavity, enhancing the effect of improving the acid resistance of dentin. Also, the feel of use becomes good.

[0015] Examples of Component (B) include calcium chloride, calcium nitrate, calcium acetate, calcium citrate, calcium glycerophosphate, calcium gluconate, calcium benzoate, calcium formate, calcium fumarate, calcium lactate, calcium butyrate, calcium isobutyrate, calcium malate, calcium maleate, calcium propionate, calcium valerate, calcium pantothenate, and the like. As Component (B), at least one selected from the group consisting of calcium chloride, calcium glycerophosphate, calcium gluconate, calcium lactate, and calcium pantothenate is preferable, and at least one selected from the group consisting of calcium chloride, calcium glycerophosphate, and calcium lactate is particularly preferable. Component (B) may be used alone or in combination of two or more. Commercially available products can be used as Component (B).

[0016] <Component (C)> Component (C) is at least one selected from the group consisting of pyrophosphoric acid and its alkali metal salts. When the oral composition contains Component (C), the effect of improving the acid resistance of dentin and the persistence of the effect of suppressing hypersensitivity-like symptoms are enhanced.

[0017] Examples of the alkali metal salt include sodium salt, potassium salt, and the like. As Component (C), from the viewpoint of acid resistance, at least one selected from the group consisting of pyrophosphoric acid, sodium pyrophosphate, and potassium pyrophosphate is preferable, and at least one selected from the group consisting of potassium pyrophosphate and sodium pyrophosphate is particularly preferable. (C) component may be used alone or in combination of two or more. (C) component may be a commercially available product.

[0018] <(D) component> (D) component is at least one selected from the group consisting of water-soluble aluminum salts and water-soluble potassium salts (however, pyrophosphates are excluded). When the oral composition contains (D) component, aluminum ions and / or potassium ions are supplied into the oral cavity, and the inhibitory effect on hypersensitivity-like symptoms is exhibited. In addition, the effect of improving the acid resistance of dentin is enhanced.

[0019] Examples of the water-soluble aluminum salts include inorganic aluminum salts such as aluminum chloride, aluminum sulfate, potassium aluminum sulfate; organic aluminum salts such as aluminum lactate, aluminum tartrate, aluminum citrate, aluminum gluconate, aluminum glycolate, aluminum malonate, aluminum glutarate, aluminum malate. Among these, aluminum lactate is preferred.

[0020] Examples of the water-soluble potassium salts include inorganic potassium salts such as potassium nitrate, potassium chloride, monopotassium phosphate, dipotassium phosphate, potassium hydroxide, potassium carbonate, potassium hydrogen carbonate, potassium aluminum sulfate, potassium sulfate; organic potassium salts such as potassium lactate, potassium sorbate, potassium citrate (monopotassium citrate, tripotassium citrate, etc.), potassium oxalate, potassium hydrogen tartrate, potassium sodium tartrate, potassium gluconate, potassium glutamate, potassium succinate, potassium malate, acesulfame potassium. Among these, potassium nitrate, potassium chloride, potassium hydroxide, potassium sulfate, potassium citrate are preferred.

[0021] (D) component is preferably at least one selected from the group consisting of aluminum lactate, potassium nitrate, potassium chloride, potassium hydroxide, potassium sulfate, and potassium citrate, and particularly preferably at least one selected from the group consisting of aluminum lactate and potassium nitrate. (D) component may be used alone or in combination of two or more. (D) component can use commercially available products.

[0022] <Content of each component> (A) The content of the component is preferably 0.09 to 1.3% by mass, more preferably 0.10 to 1.1% by mass, based on the total mass of the oral composition. When the content of the (A) component is at least the above lower limit, the acid resistance improvement effect is more excellent. When the content of the (A) component is at most the above upper limit, the feeling in use is more excellent.

[0023] (B) The content of the component is preferably 0.02 to 5.0% by mass, more preferably 0.03 to 3.0% by mass, based on the total mass of the oral composition. When the content of the (B) component is at least the above lower limit, the acid resistance improvement effect and the feeling in use are more excellent. When the content of the (B) component is at most the above upper limit, the persistence of the tooth hypersensitivity suppression effect is more excellent.

[0024] (C) The content of the component is preferably 0.02 to 3.0% by mass, more preferably 0.03 to 1.3% by mass, based on the total mass of the oral composition. When the content of the (C) component is at least the above lower limit, the acid resistance improvement effect and the persistence of the tooth hypersensitivity suppression effect are more excellent. When the content of the (C) component is at most the above upper limit, the feeling in use is more excellent.

[0025] When the (D) component contains a water-soluble aluminum salt, the content of the water-soluble aluminum salt is preferably 0.01 to 1% by mass, more preferably 0.05 to 0.5% by mass in terms of aluminum ions, based on the total mass of the oral composition. When the (D) component contains a water-soluble potassium salt, the content of the water-soluble potassium salt is preferably 0.05 to 4% by mass, more preferably 0.5 to 3% by mass in terms of potassium ions, based on the total mass of the oral composition. The content of component (D), that is, the total content of the water-soluble aluminum salt and the water-soluble potassium salt, is preferably such that the total amount of aluminum ions and potassium ions in the oral composition is within the preferable range described below.

[0026] The total amount of aluminum ions and potassium ions in the oral composition is preferably 0.01 to 5% by mass, more preferably 0.05 to 4% by mass, based on the total mass of the oral composition. When the total amount of aluminum ions and potassium ions is at least the above lower limit value, the acid resistance improvement effect and the persistence of the effect of suppressing hypersensitivity-like symptoms are more excellent. When the total amount of aluminum ions and potassium ions is at most the above upper limit value, the feeling of use is more excellent. Note that the total amount of aluminum ions and potassium ions in the oral composition may include those not derived from component (D). For example, when component (C) contains potassium pyrophosphate, the potassium ions derived from potassium pyrophosphate are also included in the above total amount.

[0027] The molar ratio of component (B) to component (C) (hereinafter also referred to as "(B) / (C)") is preferably, for example, 0.07 to 150, more preferably 0.1 to 85. When (B) / (C) is at least the above lower limit value, the feeling of use is more excellent. When (B) / (C) is at most the above upper limit value, the persistence of the effect of suppressing hypersensitivity-like symptoms is more excellent.

[0028] The molar ratio of component (B) to component (D) (hereinafter also referred to as "(B) / (D)") is preferably, for example, 0.001 to 15.0, more preferably 0.005 to 2.0. When (B) / (D) is at least the above lower limit value, the acid resistance improvement effect and the feeling of use are more excellent. When (B) / (D) is at most the above upper limit value, the acid resistance improvement effect and the persistence of the effect of suppressing hypersensitivity-like symptoms are more excellent.

[0029] <Other components> The oral composition of the present invention may further contain other components other than component (A), component (B), component (C), and component (D) as necessary, as long as the effects of the present invention are not impaired. Other components can be appropriately selected from known components in consideration of the dosage form, method of use, etc. of the oral composition. Examples of other components include water, abrasive agents, binders, thickeners, surfactants, coloring agents, sweeteners, preservatives, flavors, active ingredients, and pH adjusters.

[0030] Examples of abrasive agents include silica-based abrasive agents such as anhydrous silicic acid, precipitated silica, silica gel, aluminosilicate, and zirconosilicate; dicalcium phosphate dihydrate and anhydride, monocalcium phosphate, tricalcium phosphate, tetracalcium phosphate, calcium carbonate, calcium hydroxide, aluminum hydroxide, insoluble sodium metaphosphate, magnesium phosphate tribasic, and magnesium carbonate. In particular, silica-based abrasive agents are preferred in terms of the expression of the effects of the present invention. The content of the abrasive agent is preferably 0 to 60% by mass, more preferably 0 to 30% by mass, and may be 25% by mass or less with respect to the total mass of the oral composition. The content of the abrasive agent being 0% by mass indicates that the abrasive agent is not contained.

[0031] Examples of binders include organic binders selected from water-soluble polymer substances such as cellulose derivatives such as sodium carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, and hydroxyethyl cellulose; gums such as xanthan gum, tragacanth gum, karaya gum, and gum arabic; and polyacrylates such as sodium polyacrylate; and inorganic binders such as thickening silica, thickening aluminum silicate, veegum, and laponite. The content of the binder is preferably 0.05 to 13.0% by mass with respect to the total mass of the oral composition. When the binder contains an organic binder, the blending amount of the organic binder is more preferably 0.1 to 3% by mass, and even more preferably 0.5 to 2.5% by mass with respect to the total mass of the oral composition. When the binder contains an inorganic binder, the content of the inorganic binder is more preferably 0 to 10.0% by mass, and even more preferably 0 to 8.0% by mass with respect to the total mass of the oral composition in terms of the adsorptivity of fluoride ions to the tooth surface.

[0032] Examples of the thickening agent include sugar alcohols such as sorbitol, xylitol, erythritol, and maltitol; polyhydric alcohols such as glycerin, propylene glycol, and polyethylene glycol with an average molecular weight of 160 to 400 (average molecular weight described in the 2006 Pharmaceutical Excipients Standard). The content of the thickening agent is preferably 20 to 70% by mass, more preferably 25 to 65% by mass, based on the total mass of the oral composition.

[0033] Examples of the surfactant include nonionic surfactants, anionic surfactants, and amphoteric surfactants. Examples of the nonionic surfactant include glycerin fatty acid esters such as decaglycerin laurate; polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monostearate (average number of moles of ethylene oxide added (hereinafter abbreviated as "E.O.") 20); alkyl glycosides with 12 to 16 carbon atoms in the alkyl group; sorbitan fatty acid esters such as sorbitan tristearate; sucrose fatty acid esters such as sucrose laurate; and polyoxyethylene alkyl ethers such as polyoxyethylene stearyl ether (E.O. 6). Examples of the anionic surfactant include alkyl sulfates such as sodium lauryl sulfate and sodium myristyl sulfate; acyl sarcosinates such as sodium lauroyl sarcosinate; acyl amino acid salts such as sodium acyl glutamate; sodium acyl taurine, sodium dodecylbenzenesulfonate, sodium lauryl sulfoacetate, and sodium α-olefin sulfonate. Examples of the amphoteric surfactant include coconut oil fatty acid amidopropyl betaine, lauryldimethylaminoacetic acid betaine, and N-coconut oil fatty acid acyl-N-carboxymethyl-N-hydroxyethyl ethylenediamine. The content of the surfactant is preferably 0.05 to 10.0% by mass, more preferably 0.1 to 8.0% by mass, based on the total mass of the oral composition.

[0034] Examples of the colorant include Red No. 2, Red No. 3, Red No. 225, Red No. 226, Yellow No. 4, Yellow No. 5, Yellow No. 205, Blue No. 1, Blue No. 2, Blue No. 201, Blue No. 204, Green No. 3, mica titanium, and titanium oxide. Examples of the sweetener include sodium saccharin, aspartame, stevioside, stevia extract, paramethoxycinnamic aldehyde, neohesperidin dihydrochalcone, and perillartine. Examples of the preservative include paraoxybenzoic acid esters such as methyl paraben, ethyl paraben, and butyl paraben, and benzoic acid or its salts such as sodium benzoate.

[0035] Examples of the fragrance include natural fragrances such as peppermint oil, spearmint oil, anise oil, eucalyptus oil, wintergreen oil, cassia oil, clove oil, thyme oil, sage oil, lemon oil, orange oil, perilla oil, cardamom oil, coriander oil, mandarin oil, lime oil, lavender oil, rosemary oil, laurel oil, chamomile oil, caraway oil, marjoram oil, bay oil, lemongrass oil, oregano oil, pine needle oil, neroli oil, rose oil, jasmine oil, grapefruit oil, sweety oil, pomelo oil, iris concrete, absolute peppermint, absolute rose, orange flower, etc., and fragrances obtained by processing these natural fragrances (such as pre-cut, post-cut, fractional distillation, liquid-liquid extraction, essence formation, powder fragrance formation, etc.), menthol, carvone, anethole, cineole, methyl salicylate, cinnamic aldehyde, eugenol, 3-l-menthoxypropane-1,2-diol, thymol, linalool, linalyl acetate, limonene, menthone, menthyl acetate, N-substituted-p-menthane-3-carboxamide, pinene, octyl aldehyde, citral, pregeone, carvyl acetate, anisaldehyde, ethyl acetate, ethyl butyrate, allyl cyclohexanepropionate, methyl anthranilate, ethyl methylphenylglycidate, vanillin, undecalactone, hexanal, butanol, isoamyl alcohol, hexenol, dimethyl sulfide, cyclotene, furfural, trimethylpyrazine, ethyl lactate, ethyl thioacetate, etc., and compounded fragrances such as strawberry flavor, apple flavor, banana flavor, pineapple flavor, grape flavor, mango flavor, butter flavor, milk flavor, fruit mix flavor, tropical fruit flavor, etc. Known fragrance materials for oral compositions can be combined and used. The content of the fragrance is not particularly limited, but the content of the above fragrance materials is preferably 0.000001 to 1% by mass based on the total mass of the oral composition. The content of the flavoring fragrance using the above fragrance materials is preferably 0.05 to 2% by mass based on the total mass of the oral composition.

[0036] Examples of the active ingredient include bactericides such as isopropylmethylphenol and cetylpyridinium chloride; water-soluble phosphate compounds such as potassium salts and sodium salts of orthophosphoric acid (excluding component (C)); enzymes such as dextranase, mutanase, amylase, and protease; tranexamic acid, epsilon-aminocaproic acid, triclosan, lysozyme chloride, aluminum chlorhydroxyallantoin, hinokitiol, ascorbic acid, tocopherol acetate, dihydrocholesterol, α-bisabolol, chlorhexidine salts, azulene, water-soluble copper compounds such as copper chlorophyllin sodium, chlorophyll, and copper gluconate; strontium chloride, berberine, hydroxamic acid or its derivatives, glutyl lithic acid or its salts, glycyrrhetinic acid or its derivatives, and anti-calculus agents. The above active ingredients can be blended in an effective amount as long as the effects of the present invention are not impaired.

[0037] Examples of the pH adjuster include citric acid, tartaric acid, malic acid, and salts such as sodium salts thereof, and sodium hydroxide.

[0038] <Form, dosage form> The oral composition can be prepared in various forms such as liquid, paste, and solid. The dosage form of the oral composition is not particularly limited. The dosage form of the oral composition is typically an oral preparation that is discharged from the oral cavity after use. Examples of the oral preparation include dentifrices (liquid dentifrices, liquid dentifrices, paste dentifrices, lubricating dentifrices, powder dentifrices, etc.), mouthwashes, gargles, coating agents, mouth sprays, patches, sheet agents, sustained-release agents in the oral cavity, chewing agents, orally dissolving agents, orally disintegrating agents, tongue care agents, oral cooling agents, and denture care agents. Among the above, the oral composition of the present invention is suitable as a dentifrice, and particularly suitable as a paste dentifrice.

[0039] The oral composition of the present invention can be prepared by a known method. For example, it can be prepared by mixing component (A), component (B), component (C), and component (D), and other components as necessary, in a usual manner.

[0040] In an oral composition, it is preferable that fluoride ions, calcium ions, and phosphate ions form a complex. When the complex is formed, the retention of fluoride ions in the oral cavity is improved, and thereby, the adsorptivity of fluoride ions to the tooth surface is further improved.

[0041] The formation of the above complex can be confirmed by observing the crystallite size by X-ray crystal structure analysis and the exothermic peak when the crystal water in the vicinity of the phosphate group around 450 °C desorbs by calorimetry (TG-DTA measurement). That is, when the complex is formed, the crystallite size determined from the diffraction peak attributed to CaF 2 becomes less than 10 nm due to complexation with the phosphate group. Further, the occurrence of the crystal water peak indicates that CaF 2 observed by X-ray crystal structure analysis is not a crystal composed only of calcium and fluoride ions, but forms a complex in which phosphate groups interact. Specifically, the formation of the complex is confirmed by the crystallite size being less than 10 nm by the following method (1) and the presence of an exothermic peak at 450 °C being recognized by the following method (2). (1) Crystallite size The sample was measured with an X-ray structure diffractometer (light source Cu:Kα, 40 kV, 20 mA, divergence slit 1 / 2 deg, scattering slit 1 / 2 deg, receiving slit 0.15 mm, scan speed 4.000 ° / min, 2θ = 2.000 to 80.000 °), and the crystallite size was calculated by the following formula (Scherrer's formula) to evaluate the presence or absence of complex formation. L = Kλ / (βcosθ) L: Crystallite size, K: Coefficient 0.9, β: Half-width, λ: 1.54056 Å, θ: Diffraction angle (2) TG-DTA measurement (exothermic peak) Temperature increase rate: 5 °C / min, measurement range: 25 °C to 600 °C

[0042] The method for forming the above complex is not particularly limited. However, when preparing the oral composition, for example, it is preferable to adopt either the step of adding component (B) after adding components (A) and (C), or the step of adding component (A) after adding components (B) and (C). When components (A) and (B) are added simultaneously, a part of calcium fluoride may be generated, and the formation efficiency of the complex may be poor.

[0043] Since the oral composition described above contains component (A), component (B), component (C), and component (D), it is excellent in the effect of improving acid resistance, the persistence of the effect of suppressing dentine hypersensitivity-like symptoms, and the feeling in use.

Examples

[0044] Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following description. In the following examples, “%” indicates “% by mass” unless otherwise specified.

[0045] <Raw materials used> Sodium fluoride: manufactured by Stella Chemifa Co., Ltd. Hereinafter, it is also referred to as “NaF”. Calcium chloride: manufactured by Tomita Pharmaceutical Co., Ltd. Hereinafter, it is also referred to as “calcium chloride”. Calcium gluconate: manufactured by Fuso Chemical Industry Co., Ltd. Hereinafter, it is also referred to as “calcium gluconate”. Calcium lactate hydrate: manufactured by Taihei Chemical Industry Co., Ltd., trade name “calcium lactate”. Hereinafter, it is also referred to as “calcium lactate”. Calcium glycerophosphate: manufactured by Iwaki Pharmaceutical Co., Ltd. Hereinafter, it is also referred to as “calcium glycerophosphate”. Calcium pantothenate: manufactured by BASF. Hereinafter, it is also referred to as “calcium pantothenate”. Potassium pyrophosphate: manufactured by Taihei Chemical Industry Co., Ltd. Hereinafter, it is also referred to as “pyrophosphate K”. Sodium pyrophosphate: manufactured by Taihei Chemical Industry Co., Ltd., trade name “sodium pyrophosphate (anhydrous)”. Hereinafter, it is also referred to as “sodium pyrophosphate”. Sodium tripolyphosphate: manufactured by Taihei Chemical Industry Co., Ltd. Hereinafter, it is also referred to as “sodium tripolyphosphate”. Potassium nitrate: manufactured by Otsuka Chemical Co., Ltd. Aluminum lactate: manufactured by Fujifilm Wako Pure Chemical Corporation. Hereinafter also referred to as "lactic acid Al". Water: purified water.

[0046] <Examples 1 to 31, Comparative Examples 1 to 5> Toothpaste compositions (gel toothpastes) having the compositions shown in Tables 1 to 4 were prepared by a conventional method. An empty cell in the table indicates that the component is not blended. "Remainder" of water indicates the amount that makes the total amount of the toothpaste composition 100%. The following evaluations were performed on the obtained toothpaste compositions. The results are also shown in Tables 1 to 4.

[0047] (Evaluation of acid resistance of dentin) The toothpaste composition was diluted 4-fold with artificial saliva to prepare a treatment solution. Dentin blocks with a 3 mm × 3 mm window on the surface were prepared from bovine tooth roots. The dentin blocks were immersed in the treatment solution at room temperature for 3 minutes. Then, the dentin blocks were taken out of the treatment solution, gently rinsed with purified water to remove the treatment solution, and then immersed in a demineralization solution containing CaCl 2 : 2.2 mM, KH 2 PO 4 : 2.2 mM, acetic acid: 100 mM at pH 4.5 at 37 °C for 6 hours. Then, the dentin blocks were taken out of the demineralization solution, immersed in the treatment solution again at room temperature for 3 minutes. Then, the dentin blocks were taken out of the treatment solution, gently rinsed with purified water to remove the treatment solution, and then immersed in the centrifuged supernatant of human saliva at 37 °C for 18 hours. These series of treatments were repeated once a day for a total of 5 days. After the treatment, the dentin blocks were thoroughly rinsed with purified water and immersed in the demineralization solution at 37 °C for 6 hours. The amount of eluted calcium ions at this time was measured with an atomic absorption spectrometer. A series of experimental operations were performed with N = 3 for each example and comparative example, the average value was calculated, and the evaluation was performed according to the following evaluation criteria. [Evaluation criteria] ◎: The amount of eluted calcium ions is less than 5 μg. ○: The amount of eluted calcium ions is less than 8 μg and 5 μg or more. △: The amount of dissolved calcium ions is less than 13 μg and 8 μg or more. ×: The amount of dissolved calcium ions is 13 μg or more.

[0048] (Evaluation of the time for suppressing hypersensitivity-like symptoms) The dentifrice composition was used in the usual manner, and the inhibitory effect on hypersensitivity-like symptoms after use in the oral cavity was evaluated. Specifically, five subjects with hypersensitivity-like symptoms used the dentifrice composition twice a day for one week by the following method, and the absence of hypersensitivity-like symptoms when drinking water at 10 °C was evaluated according to the following four-level scoring criteria after a predetermined time (60 minutes, 120 minutes, 180 minutes) had elapsed since the last toothbrushing. The average score of the five subjects was calculated and judged as ◎, ○, △, or × according to the following evaluation criteria. [Method of using the dentifrice] 1 g of the dentifrice composition was placed on a toothbrush, brushed for 2 minutes, spit out, and then the mouth was rinsed with 50 mL of water. [Scoring criteria] 4 points: There are no hypersensitivity-like symptoms until 180 minutes later. 3 points: There are no hypersensitivity-like symptoms until 120 minutes later. 2 points: There are no hypersensitivity-like symptoms until 60 minutes later. 1 point: Hypersensitivity-like symptoms are felt 60 minutes later. [Evaluation criteria] ◎: The average score is 3.5 points or more. ○: The average score is 3.0 points or more and less than 3.5 points. △: The average score is 2.0 points or more and less than 3.0 points. ×: The average score is less than 2.0 points.

[0049] (Evaluation of the feeling of use) The dentifrice composition was used in the usual manner, and the absence of abnormal taste and irritation after use in the oral cavity was evaluated. Specifically, ten subjects used the dentifrice composition by the following method, and the absence of abnormal taste (fishy smell, bitterness) and irritation in the oral cavity was evaluated according to the following five-level scoring criteria after 10 minutes had elapsed. The average score of the ten subjects was calculated and judged as ◎, ○, △, or × according to the following evaluation criteria. [Method of using the dentifrice] 1 g of the dentifrice composition was placed on a toothbrush, brushed for 2 minutes, spit out, and then the mouth was rinsed with 50 mL of water. [Evaluation Criteria] 5 points: No strange smell or irritation at all. 4 points: Almost no strange smell or irritation. 3 points: Slightly feel strange smell or irritation. 2 points: Feel strange smell or irritation. 1 point: Strongly feel strange smell or irritation. [Evaluation Standards] ◎: Average score is 4.5 points or more. ○: Average score is 4.0 points or more and less than 4.5 points. △: Average score is 3.0 points or more and less than 4.0 points. ×: Average score is 1.0 points or more and less than 3.0 points.

[0050] [Table 1]

[0051] [Table 2]

[0052] [Table 3]

[0053] [Table 4]

[0054] As shown in the above results, the dentifrice compositions of Examples 1 to 31 were excellent in acid resistance of dentin, suppression time of dentin hypersensitivity-like symptoms, and feeling in use. On the other hand, all of the dentifrice compositions of Comparative Examples 1 to 5 that did not contain any of the components (A), (B), (C), and (D) were inferior in acid resistance of dentin. Comparative Example 2 that did not contain the component (B) was also inferior in feeling in use. Comparative Example 3 that did not contain the component (C) and Comparative Example 4 that did not contain the component (D) were also inferior in suppression time of dentin hypersensitivity-like symptoms.

[0055] When comparing Example 17 with Comparative Example 3 and Comparative Example 5, in Comparative Example 3 which does not contain component (C) and Comparative Example 5 which has tripolyphosphate instead of component (C), the acid resistance of dentin was △, while in Example 17 it was ◎. From this result, the remarkable effect of component (C) in improving acid resistance was confirmed.

[0056] Next, formulation examples are shown. When a dentifrice composition (gel dentifrice) having the following composition was prepared and evaluated in the same manner as in the above examples, in any of the formulation examples, it was excellent in the acid resistance of dentin, the suppression time of dentinal hypersensitivity-like symptoms, and the feel of use.

[0057] <Formulation Example 1 Dentifrice> Sodium fluoride 0.32% Calcium lactate hydrate 0.2% Sodium pyrophosphate 0.1% Potassium chloride (Yoneyama Chemical Industry Co., Ltd.) 7.5% Silicic anhydride 10% Sorbit solution (70%) 40% Propylene glycol 3% Xanthan gum 0.5% Sodium polyacrylate 0.5% Sodium lauryl sulfate 0.5% Sodium saccharin 0.2% Flavor 1% Purified water balance

[0058] <Formulation Example 2 Dentifrice> Sodium fluoride 0.32% Calcium lactate hydrate 0.2% Sodium pyrophosphate 0.1% Potassium citrate (Fuso Chemical Co., Ltd.) 10% Silicic anhydride 10% Sorbit solution (70%) 40% Propylene glycol 3% Xanthan gum 0.5% Sodium polyacrylate 0.5% Sodium lauryl sulfate 0.5% Sodium saccharin 0.2% Fragrance 1% Purified water the rest

[0059] <Formulation Example 3 Toothpaste> Sodium fluoride 0.32% Calcium lactate hydrate 0.2% Sodium pyrophosphate 0.1% Potassium sulfate (Yoneyama Chemical Industry Co., Ltd.) 5% Silicic anhydride 10% Sorbitol solution (70%) 40% Propylene glycol 3% Xanthan gum 0.5% Sodium polyacrylate 0.5% Sodium lauryl sulfate 0.5% Sodium saccharin 0.2% Fragrance 1% Purified water the rest

[0060] <Formulation Example 4 Toothpaste> Sodium fluoride 0.32% Calcium lactate hydrate 0.2% Sodium pyrophosphate 0.1% Potassium hydroxide (Kanto Chemical Co., Inc.) 10% Silicic anhydride 10% Sorbitol solution (70%) 40% Propylene glycol 3% Xanthan gum 0.5% Sodium polyacrylate 0.5% Sodium lauryl sulfate 0.5% Sodium saccharin 0.2% Fragrance 1% Purified water the rest

Claims

1. Component (A): Sodium fluoride and, Component (B): A water-soluble calcium salt, and Component (C): At least one selected from the group consisting of pyrophosphoric acid and its alkali metal salts, and Component (D): At least one selected from the group consisting of a water-soluble aluminum salt and a water-soluble potassium salt (excluding pyrophosphates), and An oral composition containing the same.

2. The oral composition according to claim 1, wherein the component (B) is at least one selected from the group consisting of calcium chloride, calcium glycerophosphate, calcium gluconate, calcium lactate, and calcium pantothenate.

3. The oral composition according to claim 1, wherein the component (C) is at least one selected from the group consisting of pyrophosphoric acid, sodium pyrophosphate, and potassium pyrophosphate.

4. The oral composition according to claim 1, wherein the component (D) is at least one selected from the group consisting of aluminum lactate and potassium nitrate.

5. The oral composition according to claim 1, wherein the molar ratio of the component (B) to the component (D) is 0.001 to 15.

0.

6. The oral composition according to claim 1, wherein the total amount of aluminum ions and potassium ions in the oral composition is 0.01 to 5% by mass based on the total mass of the oral composition.

7. The oral composition according to any one of claims 1 to 6, which is a dentifrice.

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