Dentin protectant and oral composition

Abstract

To provide a dentin protectant and an oral composition that effectively protect dentin.SOLUTION: A dentin protectant comprises at least one of an organic sulfate ester salt having a hydrocarbon group with 10 to 14 carbon atoms, a pyridinium salt having a hydrocarbon group with 12 to 18 carbon atoms, benzalkonium chloride, polyglyceryl monolaurate, and sodium tetradecenesulfonate.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a dentin protective agent and an oral composition. [Background technology]

[0002] Generally, dental caries occurs when microorganisms in dental plaque on the tooth surface metabolize sugars in food and drink to produce acid, which demineralizes hydroxyapatite crystals in the enamel and dentin. The erosion of dentin is largely related to the demineralization of hydroxyapatite crystals in dentin by acid and the breakdown of collagen contained as organic matter. In order to prevent caries from occurring in dentin, it is necessary to suppress the breakdown of collagen in dentin, and further to suppress the elution of minerals (demineralization) and promote the resorption of the minerals (remineralization). It is known that collagenases such as collagenase-type matrix metalloproteinases (MMPs) are involved in the breakdown of collagen in dentin.

[0003] Conventionally, MMP inhibitors have been known, for example as disclosed in Patent Document 1. The MMP inhibitor discloses a component consisting of gold nanoparticles having a protective agent on the surface thereof, the protective agent including a functional group capable of forming a coordinate bond with a zinc ion at an enzyme active site. The MMP inhibitor exerts an MMP activity inhibitory effect by interacting with MMP. Therefore, in order to exert the MMP inhibitory effect, it was necessary for the MMP inhibitor to coexist with MMP. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-138091 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, it is known that excessive production of collagenase leads to the degradation of collagen contained in dentin, which may facilitate the progression of caries in the dentin. Therefore, there has been a demand for a dentin protective agent that can adequately protect dentin even after mouthrinsing. [Means for solving the problem]

[0006] As a result of research conducted by the inventors to solve the above problems, they have newly discovered that certain components, such as organic sulfate ester salts having a hydrocarbon group having 10 to 14 carbon atoms, exhibit excellent dentin protection effects.

[0007] Various aspects for solving the above problems will be described below. The dentin protective agent of aspect 1 is characterized by containing at least one of an organic sulfate ester salt having a hydrocarbon group having 10 to 14 carbon atoms, a pyridinium salt having a hydrocarbon group having 12 to 18 carbon atoms, benzalkonium chloride, polyglyceryl monolaurate, and sodium tetradecene sulfonate.

[0008] Aspect 2 is the dentin protective agent described in Aspect 1, wherein the organic sulfate ester salt having a hydrocarbon group having 10 to 14 carbon atoms is at least one of sodium lauryl sulfate and sodium tetradecyl sulfate, and the pyridinium salt having a hydrocarbon group having 12 to 18 carbon atoms is at least one of cetylpyridinium chloride and dodecylpyridinium chloride.

[0009] In a third aspect, the dentin protective agent according to the first or second aspect protects collagen contained in tooth dentin. The oral composition of aspect 4 is characterized in that it contains at least one of an organic sulfate ester salt having a hydrocarbon group having from 10 to 14 carbon atoms, a pyridinium salt having a hydrocarbon group having from 12 to 18 carbon atoms, benzalkonium chloride, polyglyceryl monolaurate, and sodium tetradecene sulfonate, and is intended for protecting dentin.

[0010] Aspect 5 is the oral composition according to Aspect 4, wherein the organic sulfate ester salt having a hydrocarbon group having 10 to 14 carbon atoms is at least one of sodium lauryl sulfate and sodium tetradecyl sulfate, and the pyridinium salt having a hydrocarbon group having 12 to 18 carbon atoms is at least one of cetylpyridinium chloride and dodecylpyridinium chloride. Effect of the Invention

[0011] The dentin protective agent and oral composition of the present invention can exert an excellent dentin protective effect. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A dentin protective agent and an oral composition according to the present invention will now be described with reference to specific embodiments. Since the dentin protective agent and the oral composition contain similar components, the following description will focus on the dentin protective agent.

[0013] In the present invention, the oral composition means a composition intended to be used mainly in the oral cavity. It includes not only oral preparations that are discharged from the oral cavity after use, but also ingestible foods and beverages. The dentin protective agent is not limited to those intended to be used in the oral cavity.

[0014] The dentin protective agent contains at least one of an organic sulfate ester salt having a hydrocarbon group having 10 to 14 carbon atoms, a pyridinium salt having a hydrocarbon group having 12 to 18 carbon atoms, benzalkonium chloride, polyglyceryl monolaurate, and sodium tetradecene sulfonate.

[0015] Each component constituting the dentin protective agent will be described below. <Ingredients> Benzalkonium chloride is a type of cationic surfactant.

[0016] An organic sulfate salt having a hydrocarbon group having 10 to 14 carbon atoms is a type of anionic surfactant of organic sulfate ester type. The hydrocarbon group having 10 to 14 carbon atoms may be linear or may have a branched chain structure. Specific examples of organic sulfate salts having a hydrocarbon group having 10 to 14 carbon atoms include sodium decyl sulfate, sodium lauryl sulfate, sodium tetradecyl sulfate, etc. Among these, sodium lauryl sulfate and sodium tetradecyl sulfate are preferred from the viewpoint of excellent dentin protection effect, and sodium lauryl sulfate is more preferred.

[0017] Pyridinium salts having a hydrocarbon group with 12 to 18 carbon atoms are quaternary ammonium compounds having a pyridine ring. The hydrocarbon group with 12 to 18 carbon atoms may be linear or branched. Specific examples of pyridinium salts having a hydrocarbon group with 12 to 18 carbon atoms include cetylpyridinium chloride, dodecylpyridinium chloride, tetradecylpyridinium chloride, and octadecylpyridinium chloride. Among these, cetylpyridinium chloride and dodecylpyridinium chloride are preferred from the viewpoint of excellent dentin protection, and cetylpyridinium chloride is more preferred.

[0018] Polyglyceryl monolaurate is a type of ester-type nonionic surfactant. Sodium tetradecene sulfonate is a type of sulfonic acid type anionic surfactant.

[0019] The dentin protective agent may contain only one of the above-mentioned organic sulfate ester salts having a hydrocarbon group with 10 to 14 carbon atoms, pyridinium salts having a hydrocarbon group with 12 to 18 carbon atoms, benzalkonium chloride, polyglyceryl monolaurate, and sodium tetradecene sulfonate, or may contain an appropriate combination of two or more of them.

[0020] The content of each of the above components in the dentin protective agent is not particularly limited. The content of the organic sulfate ester salt having a hydrocarbon group with 10 to 14 carbon atoms, polyglyceryl monolaurate, and sodium tetradecene sulfonate is, for example, 0.1% by mass to 5% by mass. Hereinafter, the content of the above components in the dentin protective agent will be expressed by abbreviating "%" to "%" instead of "% by mass." The upper limit of the content of each component is preferably 4%, more preferably 2%. The lower limit of the content of each component is preferably 0.5%, more preferably 1%. The upper or lower limit of the range may be, for example, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, or 4.5%.

[0021] The content of benzalkonium chloride and pyridinium salt having a hydrocarbon group with 12 to 18 carbon atoms is, for example, 0.005% to 1%. The upper limit of the content of each component is preferably 0.75%, more preferably 0.5%. The lower limit of the content of each component is preferably 0.01%, more preferably 0.02%. The upper limit or lower limit of the range may be, for example, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, or 1.0%.

[0022] In addition, when the dentin protective agent contains two or more of an organic sulfate ester salt having a hydrocarbon group having 10 to 14 carbon atoms, a pyridinium salt having a hydrocarbon group having 12 to 18 carbon atoms, benzalkonium chloride, polyglyceryl monolaurate, and sodium tetradecene sulfonate, it is preferable that the total content is within the above numerical range.

[0023] <Other ingredients> The dentin protective agent may contain other components other than those described above, such as medicinal components, surfactants, abrasives, humectants, thickeners, stabilizers, preservatives, sweeteners, pH adjusters, antioxidants, flavorings, colorants, etc., depending on the application purpose, form, use, etc. Each of these components may be any known component that is contained in a dentin protective agent. Each of these components may be used alone or in combination of two or more.

[0024] Examples of the medicinal components include bactericides, blood circulation promoters, anti-inflammatory agents, bleeding improving agents, tissue repair agents, remineralizing agents, and hypersensitivity suppressants. Specific examples of medicinal ingredients include bactericides such as cationic bactericides such as benzethonium chloride, chlorhexidine gluconate, and chlorhexidine hydrochloride, amphoteric bactericides such as dodecyldiaminoethylglycine, halogenated diphenyl ethers such as triclosan (2',4,4'-trichloro-2-hydroxy-diphenyl ether), phenolic bactericides such as isopropylmethylphenol, and hinokitiol.

[0025] Examples of blood circulation promoters include vitamin E derivatives such as dl-α-tocopherol acetate, tocopherol succinate, and tocopherol nicotinate, and enzymes such as dextranase, amylase, protease, mutanase, lysozyme, and lytic enzyme (retic enzyme).

[0026] Anti-inflammatory agents include epsilon aminocaproic acid, dipotassium glycyrrhizinate, and the like. Examples of bleeding improving agents include tranexamic acid and ascorbic acid.

[0027] Examples of tissue repair agents include allantoin. Remineralizing agents include fluorine compounds such as sodium fluoride. Examples of anti-dentin hypersensitivity agents include nitrates (potassium nitrate), aluminum lactate, hydroxyapatite, stannous fluoride, and arginine.

[0028] Other examples include plant extracts extracted with water-soluble solvents, chlorophyll, sodium chloride, zinc chloride, potassium nitrate, etc. Specific examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants.

[0029] (Nonionic surfactant) Specific examples of nonionic surfactants include sugar fatty acid esters such as sucrose fatty acid esters and maltose fatty acid esters, sugar alcohol fatty acid esters such as maltitol fatty acid esters, sorbitan fatty acid esters such as sorbitan stearate and sorbitan monolaurate, polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan laurate (also called polysorbate 20), polyoxyethylene sorbitan stearate (also called polysorbate 60), and polyoxyethylene sorbitan oleate (also called polysorbate 80), fatty acid alkanolamides such as lauric acid diethanolamide, polyoxyethylene sorbitan fatty acid esters such as sorbitan stea ... fatty acid esters such as sorbitan stearate (also called polysorbate 60), and polyoxyethylene sorbitan fatty acid esters such as sorbitan stearate (also called polysorbate 60), and polyoxyethylene sorbitan fatty acid esters such as sorbitan stearate (also called polysorbate 60), and polyoxyethylene sorbitan fatty Examples of the polyoxyethylene alkyl ethers include polyoxyethylene stearyl ether and polyoxyethylene oleyl ether, polyethylene glycol fatty acid esters such as polyethylene glycol monooleate and polyethylene glycol monolaurate, alkyl glycosides such as lauryl glycoside and decyl glycoside, polyglycerin fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyoxyethylene fatty acid esters, alkyl glucosides, polyoxyethylene hydrogenated castor oil (those with an average number of moles of ethylene oxide added of 10, 20, 40, or 60), glycerin fatty acid esters, and polyoxyethylene propylene block copolymers.

[0030] (anionic surfactant) Specific examples of anionic surfactants include sulfate salts such as sodium polyoxyethylene lauryl ether sulfate, sulfosuccinates such as sodium lauryl sulfosuccinate and sodium polyoxyethylene lauryl ether sulfosuccinate, acylamino acid salts such as sodium cocoyl sarcosine and sodium lauroyl methyl alanine, and sodium cocoyl methyl taurate.

[0031] (Cationic Surfactant) Specific examples of cationic surfactants include quaternary alkyl ammonium salts such as cocoyl arginine ethyl PCA, cetyltrimethylammonium chloride, distearyldimethylammonium chloride, stearyldimethylbenzylammonium chloride, and stearyltrimethylammonium chloride, and chlorhexidine gluconate.

[0032] (Amphoteric surfactant) Specific examples of amphoteric surfactants include amino acid type amphoteric surfactants such as N-lauryldiaminoethylglycine and N-myristyldiethylglycine, betaine type amphoteric surfactants such as alkyldimethylaminoacetic acid betaine, N-alkyl-N'-carboxymethyl-N'-hydroxyethylethylenediamine salt, and 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine.

[0033] Specific examples of abrasives include calcium carbonate, calcium phosphate, dibasic calcium phosphate, calcium pyrophosphate, insoluble sodium metaphosphate, titanium oxide, amorphous silica, crystalline silica, abrasive silica, thickening silica, aluminosilicate, aluminum oxide, titanium oxide, aluminum hydroxide, resin, etc. The above-mentioned silica is also called silicic anhydride.

[0034] Specific examples of the humectant include propylene glycol, glycerin, sorbitol, polyethylene glycol, 1,3-butylene glycol, water, and alcohol.

[0035] Specific examples of thickeners include sodium polyacrylate, carrageenan, sodium carboxymethylcellulose, sodium alginate, xanthan gum, hydroxyethyl cellulose, crystalline cellulose, hydroxypropylmethylcellulose, methylcellulose, propylene glycol alginate, etc. Thickeners are also called binders.

[0036] Specific examples of the stabilizer include sodium edetate, sodium thiosulfate, sodium sulfite, calcium lactate, lanolin, triacetin, castor oil, magnesium sulfate, and the like.

[0037] Specific examples of preservatives include 1,2-dibromo-2,4-dicyanobutane, photosensitizers, isothiazolone derivatives, hydantoin derivatives, parabens, sodium benzoate, and phenol.

[0038] Specific examples of sweeteners include saccharin, saccharin sodium, acesulfame potassium, stevia extract, palatinose, palatinit, erythritol, maltitol, xylitol, and lactitol.

[0039] Specific examples of pH adjusters include citric acid, phosphoric acid, malic acid, pyrophosphoric acid, lactic acid, tartaric acid, glycerophosphoric acid, acetic acid, nitric acid, or chemically acceptable salts thereof, sodium hydroxide, and the like.

[0040] Specific examples of the antioxidant include tocopherols, dibutylhydroxytoluene, butylhydroxyanisole, and gallic acid esters. The flavoring may be a natural flavoring or a synthetic flavoring, and may be a single flavoring or a blend of flavorings.

[0041] Specific examples of fragrances include l-menthol, d-carvone, anethole, eugenol, methyl salicylate, limonene, ocimene, n-decyl alcohol, citronellol, α-terpineol, methyl acetate, citronellyl acetate, methyl eugenol, cineole, linalool, ethyl linalool, thymol, spearmint oil, peppermint oil, lemon oil, orange oil, sage oil, rosemary oil, perilla oil, wintergreen oil, clove oil, eucalyptus oil, pimento oil, d-camphor, d-borneol, fennel oil, cinnamon oil, cinnamaldehyde, peppermint oil, and vanillin.

[0042] Specific examples of colorants include legal dyes such as Green No. 1, Green No. 3, Blue No. 1, Yellow No. 4, Yellow No. 5, Red No. 102, and Red No. 3, sodium copper chlorophyll, and titanium oxide.

[0043] <Application form, dosage form, and uses of dentin protection agents> The application form of the dentin protective agent is not particularly limited, and it can be used, for example, as a medicine, a quasi-drug, or a cosmetic.

[0044] The formulation of the dentin protective agent is not particularly limited, and can be applied as an ointment, paste, spray, gel, liquid, suspension, gum, etc., by containing a solvent such as water or alcohol.

[0045] The type of water used as a solvent is not particularly limited, and for example, distilled water, pure water, ultrapure water, purified water, tap water, etc. can be used. The type of alcohol used as a solvent is not particularly limited, and for example, ethanol can be used. A mixture of water and alcohol can also be used.

[0046] The application form of the dentin protective agent and the oral composition is not particularly limited, and can be used as, for example, medicines, quasi-drugs, cosmetics, etc. The use of the dentin protective agent and the oral composition can be appropriately adopted from known uses. Specific examples include chewing agents, oral dissolving agents, oral disintegrating agents, tongue care agents, oral fresheners, toothpastes, mouthwashes, gargles, liquid dentifrices, biofilm dispersants, oral halitosis preventive agents, dentin hypersensitivity suppressants, gum massage agents, oral moisturizing agents, tongue coating removers, oral application agents, oral germicides, throat germicides, oral throat agents, periodontal disease treatment agents, denture mounting agents, denture coating agents, denture stabilizers, denture preservatives, denture cleaners, implant care agents, etc.

[0047] <effect> The dentin protective agent and oral composition exhibit excellent dentin protective action due to the above-mentioned components. The dentin protective agent or oral composition is applied to the oral cavity, and can suitably protect dentin for a long period of time, especially after mouthwashing. Specifically, it inhibits collagen contained in tooth dentin from being decomposed by collagenase. It is considered that the dentin protective action of the dentin protective agent or oral composition is brought about by the interaction between the compounded components and dentin, that is, the compounded components coat the dentin or are adsorbed to the dentin. It is considered that the compounded components coat the organic matter and collagen in the dentin, or are adsorbed to the organic matter and collagen in the dentin.

[0048] Due to the above-mentioned effects, the dentin protective agent and oral composition of the present embodiment can be used for protecting dentin collagen, particularly after mouthrinsing. The effects of the dentin protective agent of this embodiment will be described.

[0049] (1) The dentin protective agent of this embodiment is configured to contain at least one of an organic sulfate ester salt having a hydrocarbon group with 10 to 14 carbon atoms, a pyridinium salt having a hydrocarbon group with 12 to 18 carbon atoms, benzalkonium chloride, polyglyceryl monolaurate, and sodium tetradecene sulfonate. Therefore, it is possible to protect dentin. In particular, it is possible to suitably inhibit the progress of dentin caries by suitably inhibiting the decomposition of collagen, which is an organic substance in dentin.

[0050] The above embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs. May also be applied to pets, livestock and other captive animals other than humans. EXAMPLES

[0051] In the following, examples will be given in order to more specifically explain the configuration and effects of the present invention, but the present invention is not limited to these examples. (Test Example 1) The dentin protective agents of Examples 1 to 6 and Comparative Examples 1 to 15 shown in Table 1 were produced according to a conventional method. Specifically, the components shown in Table 1 were dissolved in water so that the concentration was 1% by mass to prepare an aqueous solution of the dentin protective agent. As a control, water alone was used.

[0052] (Evaluation test) The dentin protective agents of Examples 1 to 6 and Comparative Examples 1 to 15 were evaluated for their dentin protective effect by measuring their ability to inhibit collagen decomposition in dentin by the method described below. The evaluation method and evaluation results are shown below.

[0053] (Method for evaluating collagen degradation inhibitory activity) The dentin blocks were prepared and a collagen degradation test was carried out according to the following procedure. (Preparation of dentin blocks) First, extracted teeth from cows were prepared. A microcutter was used to cut out rectangular tooth pieces measuring approximately 5 mm x 5 mm and approximately 6 mm thick from the dentin of the extracted teeth.

[0054] This tooth fragment was embedded in polymethyl methacrylate resin (hereinafter also referred to as PMMA). The surface of the dentin block was polished using waterproof abrasive paper to expose the dentin portion. Specifically, the surface was exposed so that the above-mentioned rectangular portion of about 5 mm x about 5 mm was exposed. By the above procedure, a dentin block with the tooth fragment embedded in PMMA was produced.

[0055] (Collagen Decomposition Test) Approximately half of the surface of the exposed dentin portion (hereinafter also referred to as the reference surface) was coated with commercially available nail polish to cover the reference surface.

[0056] Next, the dentin block was immersed in 25 mL of 0.87 M citric acid solution at room temperature for 5 hours to perform demineralization. By performing demineralization, mineral components contained in the dentin were removed from the surface of the dentin that was not covered with nail polish (hereinafter, also referred to as the treated surface). By removing the mineral components, collagen contained in the dentin was exposed.

[0057] Next, the dentin protective agent of each Example and Comparative Example and artificial saliva were mixed in a volume ratio of 1:1 to prepare a test solution. When the pH of the prepared test solution was acidic, the pH of the test solution was adjusted to about 7 using 1M sodium hydroxide aqueous solution. The composition of the artificial saliva was calcium chloride (CaCl2): 1.5 mM, potassium hydrogen phosphate (KH2PO4): 0.9 mM, potassium chloride (KCl): 130 nM, and HEPES: 20 mM, and the pH was adjusted to 7.0.

[0058] The dentin block was immersed in 2 mL of each test solution while maintaining the temperature of the test solution at 37° C. The immersion was continued for 8 hours. After immersion, each dentin block was rinsed with water. Next, we prepared a commercially available collagenase, Collagenase, Type 1 (derived from Clostridium histolyticum), and artificial saliva. Collagenase was dissolved in the artificial saliva to prepare a collagenase solution with a collagenase concentration of approximately 200 U / mL.

[0059] The dentin blocks were immersed in 2 mL of each collagenase solution while maintaining the temperature at 37°C for 24 hours. After immersion, the nail polish covering the reference surface of the dentin portion was removed using acetone.

[0060] The treated surface of the dentin portion is susceptible to collagen degradation by collagenase. When collagen is decomposed, the thickness of the dentin portion on the treated surface becomes smaller than the thickness of the dentin portion on the reference surface. A known laser microscope was used to measure the height change between the reference surface and the treated surface, and this height change was taken as the decomposition depth. The decomposition depth was evaluated according to the following criteria. The smaller the value of the decomposition depth, the more the decomposition of collagen in the dentin is suppressed by the dentin protective agent, and the better the dentin protective effect.

[0061] -Decomposition depth evaluation criteria ○(Good): When the resolution is 100μm or less △ (OK): When the resolution is greater than 100μm and less than 200μm × (Not acceptable): When the resolution exceeds 200 μm

[0062] [Table 1] (Evaluation Results) From Table 1, the decomposition depth of each of the comparative examples exceeded 200 μm. In contrast, the decomposition depth of each of the examples was 200 μm or less. In particular, it was confirmed that benzalkonium chloride, sodium lauryl sulfate, and cetylpyridinium chloride have excellent dentin protection effects. In addition, each of the examples and comparative examples was tested multiple times and confirmed to fall within the same evaluation criteria.

[0063] (Test Example 2) The dentin protective agents of Example 7 and Comparative Examples 16 to 21 shown in Table 2 were produced according to a conventional method. Specifically, the components shown in Table 2 were dissolved in water so that the concentration was 1% by mass to prepare an aqueous solution of the dentin protective agent. As a control, water alone was used.

[0064] (Evaluation test) The dentin protective effect of the dentin protective agents of Example 7 and Comparative Examples 16 to 21 was evaluated by measuring the ability to inhibit collagen decomposition in dentin. The evaluation method was the same as that in Test Example 1. The evaluation results are shown in Table 2 below.

[0065] [Table 2] (Evaluation Results) From Table 2, the decomposition depth exceeded 200 μm in each of the comparative examples. In contrast, the decomposition depth was 200 μm or less in Example 7. Note that each of the examples and comparative examples was tested multiple times and confirmed to be within the same evaluation criteria.

Claims

1. A dentin protective agent characterized by containing at least one of an organic sulfate ester salt having a hydrocarbon group having 10 to 14 carbon atoms, a pyridinium salt having a hydrocarbon group having 12 to 18 carbon atoms, benzalkonium chloride, polyglyceryl monolaurate, and sodium tetradecene sulfonate.

2. the organic sulfate salt having a hydrocarbon group having 10 to 14 carbon atoms is at least one of sodium lauryl sulfate and sodium tetradecyl sulfate, The dentin protecting agent according to claim 1, wherein the pyridinium salt having a hydrocarbon group having 12 to 18 carbon atoms is at least one of cetylpyridinium chloride and dodecylpyridinium chloride.

3. The dentin protecting agent according to claim 1 or 2, which protects collagen contained in tooth dentin.

4. An oral composition characterized by comprising at least one of an organic sulfate ester salt having a hydrocarbon group having 10 to 14 carbon atoms, a pyridinium salt having a hydrocarbon group having 12 to 18 carbon atoms, benzalkonium chloride, polyglyceryl monolaurate, and sodium tetradecene sulfonate, and being used for protecting dentin.

5. the organic sulfate salt having a hydrocarbon group having 10 to 14 carbon atoms is at least one of sodium lauryl sulfate and sodium tetradecyl sulfate, 5. The oral composition according to claim 4, wherein the pyridinium salt having a hydrocarbon group having 12 to 18 carbon atoms is at least one of cetylpyridinium chloride and dodecylpyridinium chloride.

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