Dental remineralization composition containing acid hydrolyzed tea leaf extract and method of making same

Abstract

This invention discloses a tooth remineralization composition containing acid-hydrolyzed tea extract and its preparation method, belonging to the field of oral care technology. The composition comprises: 30%–70% tea extract, 1%–8% thickener, 5%–20% glycerin, 0.1%–1% flavoring, and the balance being drinking purified water. The tea extract is rich in lanthanum and cerium light rare earth elements, obtained from oolong tea through carbonization, calcination at 550℃, acid hydrolysis with dilute nitric acid, neutralization, and volume adjustment. The total rare earth element content is 2.22 × 10³ mg / kg. After remineralization with this composition, the surface microhardness of tooth enamel demineralized by bleaching with 30% hydrogen peroxide is restored by an average of 5.6%–8.0%. The raw materials of this invention are green and safe, exhibiting a significant tooth remineralization effect and effectively repairing demineralized enamel damage.

Description

Technical Field

[0001] This invention relates to the field of oral care technology, and in particular to a tooth remineralization composition containing acid-hydrolyzed tea extract and its preparation method, which is suitable for remineralization repair of demineralized tooth enamel. Background Technology

[0002] Enamel demineralization is commonly seen in teeth whitening treatments. Teeth whitening is currently the most widely used non-invasive teeth whitening method in the field of oral aesthetic restoration. Mainstream clinical and home whitening programs use peroxides such as hydrogen peroxide and urea peroxide as core active ingredients. They achieve teeth whitening by oxidizing and decomposing pigment groups on the tooth surface and deep layers. They have the advantages of being convenient, non-invasive, and fast-acting, and are widely used in the whitening treatment of extrinsically stained teeth. However, peroxide bleaching is a strong oxidative erosion process that can cause varying degrees of demineralization damage to the hard tissues of the tooth, which has become a pain point in the current teeth whitening technology industry that urgently needs to be addressed.

[0003] During teeth bleaching, highly reactive oxygen free radicals continuously damage the hydroxyapatite crystal structure of the enamel surface and subsurface, leading to enamel demineralization, lattice loosening, and postoperative complications such as enamel demineralization, decreased tooth luster, and reduced microhardness of the tooth surface. Furthermore, the loosened tooth structure after bleaching significantly reduces its resistance to the acidic oral environment and cariogenic bacteria. Without timely professional repair, teeth are highly susceptible to re-staining, secondary demineralization, and even early caries, severely impacting the durability of the bleaching treatment and overall oral health.

[0004] Currently, the conventional method for tooth remineralization is to use ordinary fluoride toothpaste. However, ordinary fluoride products have obvious technical defects: traditional fluoride repair products can only form a thin layer of fluorapatite, and the remineralization repair effect is limited. Moreover, according to the "GB / T 8372-2017 Toothpaste" standard, the fluoride ion content usually cannot exceed 0.15%, and the repair effect of low fluoride formulas is negligible.

[0005] Based on this, developing a specialized tooth remineralization repair composition that can repair enamel demineralization damage has significant clinical application value and market promotion significance.

[0006] Light rare earth ions such as Due to ionic radius and Similarly, lanthanum-doped hydroxyapatite can be incorporated into hydroxyapatite crystals, replacing calcium in the hydroxyapatite (HAp) within the tooth structure in situ, forming a denser and more acid-resistant rare-earth-doped hydroxyapatite structure. This structure has been used in oral mineralization research in recent years. Existing studies have confirmed that lanthanum-doped hydroxyapatite possesses advantages such as long-lasting antibacterial activity, enhanced acid resistance of the mineralized layer, and deep sealing of dentinal tubules. Lanthanum ions can disrupt the cell membranes of cariogenic bacteria, inhibit biofilm formation, and simultaneously regulate the orderly growth of mineralized crystals, significantly improving enamel hardness. Summary of the Invention

[0007] Based on the above description, the purpose of this invention is to provide a tooth remineralization composition containing acid-hydrolyzed tea extract and its preparation method. By utilizing the light rare earth elements contained in the tea extract, a tooth remineralization composition can be prepared, which can effectively repair demineralization damage to tooth enamel.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a tooth remineralization composition containing acid-hydrolyzed tea extract, comprising the following components by mass percentage: 30-70% tea extract, 1%-8% thickener, 5%-20% glycerin, 0.1-1% flavoring, and the balance being drinking purified water; the tea extract is an extract containing light rare earth elements, primarily lanthanum and cerium. The thickener is one of acrylic polymers, poloxamer, cellulose ethers, polyvinylpyrrolidone, or natural thickeners. The acrylic polymer is a copolymer of hydroxyethyl acrylate / sodium acryloyl dimethyl taurate or carbomer; the cellulose ether is methylcellulose, carboxymethyl cellulose, ethyl cellulose, or hydroxypropyl methylcellulose, etc.; the natural thickener is derived from natural plants, animals, or microorganisms, such as guar gum, carrageenan, gum arabic, xanthan gum, gelatin, etc. Preferably, the preparation steps of the tea extract are as follows: 1) Crushing: Crush the tea leaves, sieve them to obtain tea powder; 2) Carbonization: Place the tea powder on an electric ceramic furnace for carbonization until the tea leaves turn completely black; 3) Calcination: Preheat the muffle furnace, place the carbonized tea powder into the furnace chamber for calcination until ashing; turn off the muffle furnace, allow it to cool naturally to room temperature, and then remove it to obtain tea ash; 4) Acid hydrolysis: Slowly add dilute nitric acid to the tea ash obtained in step 3), stir to completely wet the ash; then stir for a certain time under a constant temperature water bath, and filter the acid hydrolysate; 5) Concentration, neutralization, and volume adjustment: Evaporate and concentrate the acid hydrolysate obtained in step 4) under ventilated conditions, then adjust the pH to 4.5-5.0 with potassium hydroxide solution, and finally make up the volume with drinking purified water to obtain the tea extract; the total rare earth element content in the tea extract is 2.10×10⁻⁶. 3 -2.30×10 3 mg / kg.

[0009] In the calcination process, the muffle furnace is preheated to 530-570℃, and the carbonized tea powder is placed in the furnace chamber and calcined at 530-570℃ until it becomes ashed.

[0010] In the acid hydrolysis step, the mass concentration of dilute nitric acid is 10%, and the acid hydrolysis conditions are stirring at 200-300 rpm for 20-40 minutes in a water bath at 50-70℃.

[0011] The tea used in this invention is oolong tea with stems and leaves, especially oolong tea with stems and leaves produced from mature branches and leaves in the high mountains of Anxi, Fujian.

[0012] The method for preparing a tooth remineralization composition containing acid-hydrolyzed tea extract is as follows: S1: Dissolve tea extract, purified drinking water, and glycerin by stirring to obtain a primary solution; S2: Add flavoring and thickener to the primary solution, and stir at a high speed of 1000~2000 rpm for 5-15 minutes to obtain a gel-like substance; S3: The gel obtained in S2 is degassed under vacuum to obtain a tooth remineralization composition containing acid-hydrolyzed tea extract.

[0013] The composition of this invention is a gel formulation and can be applied directly to the tooth surface after teeth whitening, 1-2 times daily. In this invention, the tea extract contains... , Light rare earth ions, due to their ionic radius and Similarly, it is possible to dope into the hydroxyapatite lattice in the demineralized region of tooth enamel, replacing calcium ions in situ to form a denser and more acid-resistant rare earth-doped hydroxyapatite structure, thereby achieving remineralization repair.

[0014] Compared with the prior art, the present invention has the following beneficial effects: (1) Significant remineralization effect: This invention utilizes the naturally enriched light rare earth elements (mainly lanthanum and cerium) in tea leaves to effectively remineralize demineralized tooth enamel. Experimental results show that after treatment with the composition of this invention, the microhardness of the demineralized tooth enamel surface after oxide bleaching can be restored by an average of 5.6%-8.0%, which is significantly better than the traditional fluoride-containing formula (only 0.9% recovery rate). Moreover, the remineralization effect increases in a dose-dependent manner with the increase of tea extract content.

[0015] (2) Natural and safe source: The rare earth elements used in this invention are derived from the natural enrichment of tea leaves, avoiding the harmful impurities that may be introduced by chemical synthesis of rare earth reagents. It is a green, natural, edible source with high biological safety.

[0016] (3) Raw materials are cheap and readily available, and resources are recycled: The raw materials are oolong tea with stems and leaves produced from mature old branches and leaves in Anxi, Fujian. It is an agricultural by-product, cheap and readily available, suitable for large-scale application, and realizes the high-value utilization of agricultural by-products.

[0017] (4) Synergistic desensitization effect: In addition to rare earth elements, tea extract also contains potassium nitrate (a well-known desensitizing component for teeth), which can exert a desensitizing effect while remineralizing, effectively relieving dentin hypersensitivity symptoms that may occur after teeth whitening.

[0018] (5) Stable formulation and controllable process: The composition of the present invention has a simple formulation, a simple and controllable preparation process, stable product quality, is suitable for industrial production, and has broad market application prospects. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to specific embodiments and comparative examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. In the following embodiments, the percentages of each substance are mass percentages. In order to achieve consistency with the substances in the comparative examples, the thickener selected in the examples and comparative examples is a hydroxyethyl acrylate / sodium acryloyldimethyl taurate copolymer.

[0020] Example 1, a tooth remineralization composition containing acid-hydrolyzed tea extract, comprising the following components by weight percentage: 30% tea extract, 4% hydroxyethyl acrylate / sodium acryloyl dimethyl taurate copolymer, 10% glycerin, 0.3% fragrance, and the balance being drinking purified water; the tea extract is an extract containing light rare earth elements, mainly lanthanum and cerium.

[0021] Example 2, a tooth remineralization composition containing acid-hydrolyzed tea extract, comprising the following components by weight percentage: 50% tea extract, 4% hydroxyethyl acrylate / sodium acryloyl dimethyl taurate copolymer, 10% glycerin, 0.3% fragrance, and the balance being drinking purified water; the tea extract is an extract containing light rare earth elements, mainly lanthanum and cerium.

[0022] Example 3, a tooth remineralization composition containing acid-hydrolyzed tea extract, comprising the following components by weight percentage: 70% tea extract, 4% hydroxyethyl acrylate / sodium acryloyl dimethyl taurate copolymer, 10% glycerin, 0.3% fragrance, and the balance being drinking purified water; the tea extract is an extract containing light rare earth elements, mainly lanthanum and cerium.

[0023] The preparation methods for the tea extracts in Examples 1, 2, and 3 are the same, and the preparation steps are as follows: 1) Pulverization: Pulverize the tea leaves and pass them through a 40-mesh sieve to obtain tea powder; the tea used is oolong tea with stems and leaves produced from mature branches and leaves in the high mountains of Anxi, Fujian; 2) Carbonization: Place 2.5 kg of tea powder in a clean glass container, and slowly and continuously heat an appropriate amount of tea powder on an electric ceramic stove each time to carbonize it until the tea leaves turn completely black and there is no crackling or splashing sound; 3) Calcination: Preheat the muffle furnace to 550°C, put the carbonized tea powder into the furnace chamber of the muffle furnace for calcination until it becomes ash; turn off the muffle furnace, let it cool naturally to room temperature, and then take it out to obtain tea ash. 4) Acid hydrolysis: Slowly add 200-300g of 10% dilute nitric acid to the tea ash obtained in step 3), and gently stir with a glass rod to completely wet the ash; then stir at 200-300rpm for 30 minutes in a constant temperature 60℃ water bath, and filter the acid hydrolysate; 5) Concentration, neutralization, and volume adjustment: Under ventilation conditions, evaporate and concentrate the acid hydrolysate obtained in step 4) to about 25g, while most of the excess nitric acid volatilizes in the process; then adjust the pH to 4.5-5.0 with potassium hydroxide solution, and finally adjust the volume to 50ml with drinking purified water to obtain the tea extract; the total rare earth element content in the tea extract is 2.22×10 3 mg / kg; 30% of the tea extract in Example 1, i.e., the total rare earth elements in the composition of Example 1 are 0.666 × 10 mg / kg. 3 mg / kg; 50% of the tea extract in Example 2, i.e., the composition of Example 2 contains 1.11 × 10 mg / kg of total rare earth elements. 3 mg / kg; 70% of the tea extract in Example 3, i.e., the composition of Example 3 contains 1.554 × 10 mg / kg of total rare earth elements. 3 mg / kg. The detection results of the tea extracts in Examples 1, 2, and 3 are shown in Table 1. Table 1: Physicochemical Test Results of Tea Extract:

[0024] ND indicates not detected.

[0025] The tea ash obtained from the high-temperature calcination of carbonized tea powder, after acid hydrolysis and filtration with dilute nitric acid, showed virtually no organic residue. The filter cake was an inorganic, insoluble residue, and the filtrate contained only trace amounts of inorganic soluble salts. The final tea extract had a total rare earth element content of 2.22 × 10⁻⁶. 3 mg / kg, the remaining components of this extract are mostly water, and a small amount of potassium nitrate formed after the residual dilute nitric acid is neutralized by potassium hydroxide.

[0026] The tooth remineralization compositions containing acid-hydrolyzed tea extract in Examples 1, 2, and 3 were prepared using the same method, as follows: S1: Dissolve tea extract, purified drinking water, and glycerin by stirring to obtain a primary solution; S2: Add flavoring and thickener to the primary solution, and stir at a high speed of 1000~2000 rpm for 10 minutes to obtain a gel-like substance; S3: The gel obtained in S2 is degassed under vacuum to obtain a tooth remineralization composition containing acid-hydrolyzed tea extract.

[0027] Comparative Example 1: A tooth remineralization composition comprising the following components by weight percentage: 0.33% sodium fluoride, 4% hydroxyethyl acrylate / sodium acryloyl dimethyl taurate copolymer, 10% glycerin, 0.3% fragrance, and the balance being drinking purified water.

[0028] The preparation method of the tooth remineralization composition in Comparative Example 1 is the same as that of the tooth remineralization compositions containing acid-hydrolyzed tea extract in each example, except that the tea extract is replaced with sodium fluoride.

[0029] In accordance with the requirements of the "GB / T 8372-2017 Toothpaste" standard, 0.33% sodium fluoride was added in the comparative proportion, which is equivalent to 0.15% fluoride ions.

[0030] 1. Experimental Design and Results 1) Preparation of dental specimens Referring to the standard "YY / T 0825 Dental Science External Bleaching Products for Teeth", select bovine teeth with at least 1 mm thick enamel tissue, remove residual soft tissue, store the teeth in a neutral solution that is sterilized but does not change the physical properties of the sample, grind the two sides of the crown with a file to make them parallel, number each sample, and make 10 samples per group. Prevent dehydration during the sample preparation process.

[0031] 2) Measurement of the microhardness of tooth enamel surface before tooth bleaching treatment After cleaning and drying the sample, fix the outer surface of the enamel horizontally on the fixture with the outer surface facing upward. Apply a load of 0.49N (equivalent to 50g load) to the enamel surface with the Vickers microhardness tester indenter and hold for 15s. Measure the microhardness value of the enamel. Perform three indentation tests on each sample and take the average value.

[0032] 3) Teeth whitening treatment Referring to the conventional teeth whitening procedure, a teeth whitening agent containing 30% hydrogen peroxide is used. An appropriate amount of the teeth whitening agent is applied to the entire surface of the sample tooth, with a thickness of about 1 mm.

[0033] After turning on the teeth whitening device, adjust the light source angle to be perpendicular to the sample surface at 90°, and continuously irradiate for 3 sessions of 10 minutes. After each 10-minute interval, clean the tooth surface and apply new teeth whitening agent. After the irradiation is complete, rinse the sample with water and blow it dry.

[0034] 4) Measurement of the microhardness of tooth enamel surface after tooth bleaching treatment After the tooth samples were dried after bleaching, the microhardness value of the enamel surface was measured using a Vickers microhardness tester. Each sample was subjected to three indentation tests, and the average value was taken.

[0035] 5) Remineralization of bleached tooth samples Apply an appropriate amount of remineralizing gel to the bleached tooth surface of the sample, leave for 30 minutes, then rinse and dry. Apply fresh remineralizing gel and leave for another 30 minutes. Afterward, rinse the sample with water and let it sit overnight, avoiding dehydration during the process.

[0036] 6) Microhardness measurement of remineralized enamel surface After the remineralized teeth were dried, the microhardness value of the enamel surface was measured using a Vickers microhardness tester. Each sample was subjected to three indentation tests, and the average value was taken.

[0037] 7) Calculate the rate of decrease in microhardness of tooth enamel surface after bleaching treatment. In the formula: --The rate of decrease in enamel hardness after bleaching treatment; --Average hardness of tooth enamel before bleaching; --The average hardness of tooth enamel after bleaching.

[0038] 8) Calculate the rate of increase in microhardness of the enamel surface after remineralization treatment. In the formula: --The rate of increase in enamel hardness after remineralization treatment; --Average hardness of tooth enamel before remineralization (i.e. after bleaching). --The average hardness of tooth enamel after bleaching.

[0039] Experimental results Table 2 shows the experimental results of the tooth remineralization composition containing acid-hydrolyzed tea extract in Example 1; Table 3 shows the experimental results of the tooth remineralization composition containing acid-hydrolyzed tea extract in Example 2; and Table 4 shows the experimental results of the tooth remineralization composition containing acid-hydrolyzed tea extract in Example 3.

[0040] Table 2: Experimental Results of the Tooth Remineralization Composition Containing Acid-hydrolyzed Tea Extract in Example 1

[0041] Table 3. Experimental results of the tooth remineralization composition containing acid-hydrolyzed tea extract in Example 2.

[0042] Table 4. Experimental results of the tooth remineralization composition containing acid-hydrolyzed tea extract in Example 3.

[0043] Table 5: Experimental Results of the Tooth Remineralization Composition in Comparative Example 1

[0044] The above experiments show that in Examples 1, 2, 3 and Comparative Example 1, the bleached tooth samples all underwent demineralization, with the average decrease in microhardness of the tooth surface being 8.8%, 8.4%, 8.9%, and 8.5%, respectively. The examples containing acid-hydrolyzed tea extract effectively remineralized the bleached teeth. After remineralization, the hardness of Examples 1, 2, and 3 increased by an average of 5.6%, 7.0%, and 8.0%, respectively, and the hardness values ​​of each sample basically recovered to near their values ​​before bleaching. As mentioned above, the acid-hydrolyzed tea extract contains a small amount of light rare earth elements, mainly lanthanum and cerium. The remaining components of the extract are mostly drinking purified water, and a small amount of potassium nitrate formed by the neutralization of residual dilute nitric acid with potassium hydroxide. Potassium nitrate is a known desensitizing agent for teeth, which can prevent repolarization after the initial depolarization of the dental nerve and reduce the activity of sensory nerves in the dental pulp or dentin, but it has no remineralization effect. Therefore, the remineralization effect of each example mainly benefits from the rare earth elements in the acid-hydrolyzed tea extract.

[0045] Comparative Example 1, containing 0.33% sodium fluoride (equivalent to 0.15% fluoride ions), showed only a slight remineralization effect, with the hardness increasing by an average of only 0.9% after remineralization. This demonstrates that the remineralization repair effect of the traditional low-fluoride formula is much worse.

Claims

1. A tooth remineralization composition containing acid-hydrolyzed tea extract, characterized in that, It includes the following components by weight percentage: 30-70% tea extract, 1%-8% thickener, 5%-20% glycerin, 0.1-1% flavoring, and the balance being purified drinking water; the tea extract is an extract containing light rare earth elements, mainly lanthanum and cerium.

2. The tooth remineralization composition containing acid-hydrolyzed tea extract according to claim 1, characterized in that, The thickener is one of acrylic polymers, poloxamer, cellulose ethers, polyvinylpyrrolidone, or natural thickeners.

3. The tooth remineralization composition containing acid-hydrolyzed tea extract according to claim 1, characterized in that, The preparation steps of the tea extract are as follows: 1) Grinding: Grind the tea leaves into powder, sift them, and obtain tea powder; 2) Carbonization: Place the tea powder on an electric ceramic stove for carbonization until the tea leaves turn completely black; 3) Calcination: The muffle furnace is preheated, and the carbonized tea powder is placed into the furnace chamber for calcination until it becomes ashed; the muffle furnace is turned off, and the tea powder is taken out after cooling naturally to room temperature to obtain tea ash. 4) Acid hydrolysis: Slowly add dilute nitric acid to the tea ash obtained in step 3) and stir to completely wet the ash; then stir for a certain time in a constant temperature water bath and filter the acid hydrolysis solution. 5) Concentration, neutralization and volume adjustment: Under ventilation conditions, evaporate and concentrate the acid hydrolysate obtained in step 4), then adjust the pH to 4.5-5.0 with potassium hydroxide solution, and finally adjust the volume with drinking purified water to obtain tea extract; The total rare earth element content in the tea extract was 2.10 × 10⁻⁶. 3 -2.30×10 3 mg / kg.

4. The tooth remineralization composition containing acid-hydrolyzed tea extract according to claim 3, characterized in that, In the calcination process described in 3), the muffle furnace is preheated to 530-570℃, and the carbonized tea powder is placed in the furnace chamber of the muffle furnace and calcined at 530-570℃ until it is ashed.

5. The tooth remineralization composition containing acid-hydrolyzed tea extract according to claim 3, characterized in that, In step 4) of acid hydrolysis, the mass concentration of dilute nitric acid is 10%, and the acid hydrolysis conditions are stirring at 200-300 rpm for 20-40 minutes in a water bath at 50-70℃.

6. The tooth remineralization composition containing acid-hydrolyzed tea extract according to claim 3, characterized in that, The tea mentioned in step 1) is oolong tea with stems and leaves.

7. A method for preparing a tooth remineralization composition containing acid-hydrolyzed tea extract, comprising the tooth remineralization composition containing acid-hydrolyzed tea extract as described in any one of claims 1-6, characterized in that, The preparation method is as follows: S1: Dissolve tea extract, purified drinking water, and glycerin by stirring to obtain a primary solution; S2: Add flavoring and thickener to the primary solution, and stir at a high speed of 1000~2000 rpm for 5-15 minutes to obtain a gel-like substance; S3: The gel obtained in S2 is degassed under vacuum to obtain a tooth remineralization composition containing acid-hydrolyzed tea extract.

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