Anti-sensitive toothpaste bioactive filler and preparation method thereof

Abstract

The invention provides an anti-sensitive toothpaste bioactive filler and a preparation method thereof. The bioactive filler comprises micron-sized triclinite (the particle size is 0.1-10 microns) and nano fluorine-silicon doped hydroxyapatite (the particle size is 70-120 nm). The mass concentration of a fluorine element and a silicon element in the nano fluorine-silicon doped hydroxyapatite in the bioactive filler is not greater than 2.0 wt%, and the mass ratio of the nano fluorine-silicon doped hydroxyapatite to the triclinite is (0-20): (80-100). When the anti-sensitive toothpaste bioactive filler is used, demineralized enamel and a demineralized dentin sheet can be helped to be biomineralized, the enamel surface is repaired, the pore diameter of a dentinal tubule is reduced, even the dentinal tubule is blocked, and mineralization deposition on the surface of dentin is promoted. According to the invention, the repairing function of the toothpaste on enamel and dentin is obviously improved.

Description

Technical Field

[0001] The present invention relates to the technical field of biomaterials, and particularly to a bioactive filler for anti-sensitivity toothpaste and a preparation method thereof. Background Art

[0002] Dentin hypersensitivity (DH) is a common clinical problem caused by the exposure of dentinal tubules. Stimuli such as cold, heat, and chemicals often increase the fluid flow in the dentinal tubules, stimulating the mechanoreceptor nerves in the tubules and causing short-term severe pain. Currently, using desensitizers to block the exposed dentinal tubules is considered an effective method to prevent irritation. Generally speaking, an ideal desensitizer should be able to produce long-term stable minerals, effectively fill the inside of the dentinal tubules, and form a mineralized layer on its surface. However, the existing desensitizers, such as fluoride salts and oxalates, do not have satisfactory effects. Their efficiency in blocking dentinal tubules is limited, and the minerals produced are easily destroyed and dissolved in dietary acids. The diameter of the dentinal tubules hinders the filling of various current desensitizers, while calcium ions and phosphate ions are easy to penetrate into the dentinal tubules, so they have great prospects in the treatment of DH.

[0003] Currently, there are mainly two types of anti-sensitivity toothpastes that produce calcium ions and phosphate ions on the market, and their active ingredients are bioactive glass and nano-hydroxyapatite. For example, a patent with the publication number CN115463041A provides an anti-sensitivity toothpaste with cold light whitening effect and a preparation method thereof. The bioactive glass material added to the formula can deposit osteoid-like apatite on the tooth surface, having the effect of promoting the remineralization of the tooth surface, but this process takes a long time and often requires more than two weeks in clinical trials. The patent with the publication number CN112891234A provides a biphasic calcium phosphate material, including brushite and hydroxyapatite, which realizes the tooth structure repair effect by forming a hydroxyapatite protection layer. Toothpaste containing ordinary hydroxyapatite has a certain filling effect on dentinal tubules, but its low solubility limits its effect.

[0004] Compared with the above two desensitizers, it will be a better choice to use a fast-mineralizing desensitizer containing calcium and phosphorus with high solubility in combination with hydroxyapatite to treat dentin hypersensitivity. Because tricalcium phosphate is the precursor of hydroxyapatite and can be converted into hydroxyapatite in a short time, the addition of tricalcium phosphate can further strengthen the filling of dentinal tubules. The addition of nano-fluorosilicon-doped hydroxyapatite is more likely to enter the dentinal tubules and further strengthen the above mineralization process.

[0005] In view of this, it is necessary to design an improved preparation method of the bioactive filler for anti-sensitivity toothpaste to solve the above problems. Summary of the Invention

[0006] In view of the above problems, the object of the present invention is to provide a bioactive filler for anti-sensitivity toothpaste and a preparation method thereof. A novel mixed material of triclinic calcium phosphate and nano-fluorosilicon-doped hydroxyapatite is developed by homogeneous precipitation method for the care of dentin hypersensitivity. By adding triclinic calcium phosphate, the remineralization ability of the anti-sensitivity component is obtained; by adding nano-fluorosilicon-doped hydroxyapatite, the chance of the anti-sensitivity component entering the dentinal tubules during the brushing friction process is increased, which is more conducive to the mineralization and sealing of the exposed dentinal tubules. The added nano-fluorosilicon-doped hydroxyapatite mimics the mineralized components of fluoride on the enamel surface.

[0007] The preparation method of a bioactive filler for anti-sensitivity toothpaste provided by the present invention specifically includes the following steps:

[0008] S1. Prepare triclinic calcium phosphate for later use;

[0009] S2. Prepare nano-fluorosilicon-doped hydroxyapatite for later use;

[0010] S3. Mix the triclinic calcium phosphate prepared in step S1 and the nano-fluorosilicon-doped hydroxyapatite prepared in step S2 according to a preset mass ratio, and fully stir to obtain a mixed powder, which is the bioactive filler for anti-sensitivity toothpaste.

[0011] The preparation method of the triclinic calcium phosphate includes the following steps:

[0012] S11. Prepare a calcium acetate solution for later use;

[0013] S12. Prepare a dilute phosphoric acid solution according to a preset mass ratio of calcium acetate to phosphoric acid for later use;

[0014] S13. Stir and heat the calcium acetate solution prepared in step S11, and then add acetic acid, and fully stir to obtain a mixed solution;

[0015] S14. Add the dilute phosphoric acid solution prepared in step S12 to the mixed solution in step S13 for reaction. After the reaction is completed, filter, wash, and spray dry to obtain triclinic calcium phosphate powder.

[0016] The preparation method of the nano-fluorosilicon-doped hydroxyapatite includes the following steps:

[0017] S21. Prepare a calcium nitrate tetrahydrate solution for later use;

[0018] S22. Prepare a tetraethoxysilane solution for later use;

[0019] S23. Prepare a mixed solution of diammonium hydrogen phosphate and ammonium fluoride for later use;

[0020] S24. Add the tetraethoxysilane solution prepared in step S22 to the reaction kettle, heat and stir; then add the calcium nitrate tetrahydrate solution prepared in step S21 to the reaction kettle, add ammonia water, and stir for 3 h;

[0021] S25. After the stirring is completed, add dropwise the mixed solution of diammonium hydrogen phosphate and ammonium fluoride prepared in step S23 to the reaction kettle, and at the same time add dropwise ammonia water, and the addition of ammonia water ends before the addition of the mixed solution of diammonium hydrogen phosphate and ammonium fluoride in step S23 is completed; continue to stir for 3 h, and after aging, wash and remove the supernatant, and collect the precipitate to obtain nano-fluorosilicon-doped hydroxyapatite powder.

[0022] As a further improvement of the present invention, the preset mass ratio of nano-fluorosilicon-doped hydroxyapatite and tricalcium phosphate in the bioactive filler of the anti-sensitivity toothpaste is (0-20):(80-100).

[0023] In step S12, the mass ratio of calcium acetate to phosphoric acid is (1-2):1.

[0024] In step S13, the heating temperature is 60-70 °C, and the addition amount of acetic acid is 0-20 g.

[0025] In step S14, the reaction temperature is 60-70 °C, and the reaction time is 2-4 h.

[0026] In step S24, the heating temperature is 80-90 °C.

[0027] In step S25, the aging time is at least 12 h.

[0028] In the preparation method of nano-fluorosilicon-doped hydroxyapatite, the mass ratio of calcium nitrate tetrahydrate, tetraethoxysilane, diammonium hydrogen phosphate, and ammonium fluoride is (38-42):(0.8-1.2):(12-14):(0.03-0.05).

[0029] To achieve the above object, the present invention also provides a bioactive filler for anti-sensitivity toothpaste, and the bioactive filler for anti-sensitivity toothpaste is prepared according to the above technical solution.

[0030] The beneficial effects of the present invention are:

[0031] (1) The present invention provides a bioactive filler for teeth remineralization toothpaste with brushite and nano-fluorosilicon-doped hydroxyapatite as raw material components. The raw materials are safe and effective. When using the toothpaste containing this bioactive filler, nano-fluorosilicon-doped hydroxyapatite is more likely to enter and fill the dentinal tubules. Brushite can undergo a mineralization reaction after contacting the dentinal tubules, blocking the exposed dentinal tubules, promoting the deposition of minerals on the tooth surface, inducing the remineralization of dental caries, and repairing the enamel structure. The bioactive filler for anti-allergic and teeth remineralization toothpaste of the present invention has the functions of both sealing the dentinal tubules and inducing the remineralization of enamel, and has the advantages of effectively improving dental caries and fundamentally eliminating dentin hypersensitivity symptoms.

[0032] (2) The ratio of brushite and nano-fluorosilicon-doped hydroxyapatite of the present invention can be artificially controlled and is applicable to different scenarios.

[0033] (3) The preparation method of the bioactive filler for toothpaste provided by the present invention has a simple process, the materials are uniform and stable, the yield is high, the cost is low, and it is easy to be industrially produced. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is the electron microscope morphology diagram of the brushite prepared in Example 1.

[0035] Figure 2 It is the electron microscope morphology diagram of the nano-fluorosilicon-doped hydroxyapatite prepared in Example 2.

[0036] Figure 3 It is the XRD and infrared diagrams of the anti-sensitivity bioactive filler for toothpaste prepared in Example 4.

[0037] Figure 4 It is the electron microscope morphology diagram of the toothpaste samples provided in Examples 5 - 6 and Comparative Examples 2 - 4 for blocking dentinal tubules.

[0038] Figure 5 It is the filling rate of the toothpaste samples provided in Examples 5 - 6 and Comparative Examples 2 - 4 for blocking dentinal tubules. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail below with reference to the drawings and specific embodiments.

[0040] Here, it also needs to be noted that in order to avoid obscuring the present invention due to unnecessary details, only the structures and / or processing steps closely related to the solution of the present invention are shown in the drawings, and other details less related to the present invention are omitted.

[0041] In addition, it should be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device.

[0042] The present invention provides a method for preparing a bioactive filler for anti-sensitivity toothpaste, comprising the following steps:

[0043] S1. Prepare tricalcium phosphate for standby.

[0044] Specifically, it includes the following steps:

[0045] S11. Prepare a calcium acetate solution for standby;

[0046] S12. Prepare a dilute phosphoric acid solution for standby according to a preset mass ratio of calcium acetate to phosphoric acid of (1-2):1;

[0047] S13. Stir and heat the calcium acetate solution prepared in step S11 to 60-70 °C, then add 0-20 g of acetic acid, and obtain a mixed solution after sufficient stirring;

[0048] S14. Add the dilute phosphoric acid solution prepared in step S12 to the mixed solution in step S13 for reaction, the reaction temperature is 60-70 °C, the reaction time is 2-4 h, after the reaction is completed, filter and wash, and spray dry to obtain tricalcium phosphate powder.

[0049] S2. Prepare nano-fluorosilicon-doped hydroxyapatite for standby.

[0050] Specifically, it includes the following steps:

[0051] S21. Prepare a calcium nitrate tetrahydrate solution for standby;

[0052] S22. Prepare a tetraethoxysilane solution for standby;

[0053] S23. Prepare a mixed solution of diammonium hydrogen phosphate and ammonium fluoride for standby;

[0054] S24. Add the tetraethoxysilane solution prepared in step S22 to the reaction kettle, heat to 80-90 °C and stir; then add the calcium nitrate tetrahydrate solution prepared in step S21 to the reaction kettle, add ammonia water, and stir for 3 h;

[0055] S25. After stirring is completed, the mixed solution of diammonium hydrogen phosphate and ammonium fluoride prepared in step S23 is added dropwise to the reaction kettle, and at the same time, ammonia water is added dropwise. The addition of ammonia water ends before the addition of the mixed solution of diammonium hydrogen phosphate and ammonium fluoride in step S23 is completed; stirring is continued for 3 h, and after aging for at least 12 h, the supernatant is removed by washing, and the precipitate is collected to obtain nano-fluorosilicon-doped hydroxyapatite powder.

[0056] The mass ratio of calcium nitrate tetrahydrate, tetraethoxysilane, diammonium hydrogen phosphate, and ammonium fluoride is (38 - 42):(0.8 - 1.2):(12 - 14):(0.03 - 0.05).

[0057] S3. The tricalcium phosphate in step S1 and the nano-fluorosilicon-doped hydroxyapatite in step S2 are mixed according to a preset mass ratio of (0 - 20):(80 - 100), and after sufficient stirring, a mixed powder is obtained, which is the bioactive filler for anti-sensitivity toothpaste.

[0058] The following specifically describes the bioactive filler for anti-sensitivity toothpaste provided by the present invention and its preparation method in conjunction with specific embodiments.

[0059] Example 1

[0060] This example provides a preparation method of tricalcium phosphate, including the following steps:

[0061] S1. Weigh 60 g of calcium acetate, measure 600 mL of pure water, and add calcium acetate and pure water to the flask.

[0062] S2. Weigh 60 g of phosphoric acid according to the mass ratio of calcium acetate to phosphoric acid of 1:1, and make up the volume to 100 mL with water.

[0063] S3. Stir and heat the calcium acetate solution prepared in step S1 to 60 °C, then add 10 g of acetic acid, and stir well to obtain a mixed solution.

[0064] S4. Add dropwise the dilute phosphoric acid solution prepared in step S2 to the mixed solution in step S3 for mixing, and stir and react in a water bath at 65 °C for 3 h. After the reaction is completed, filter and wash, and spray dry to obtain tricalcium phosphate powder.

[0065] Example 2

[0066] This example provides a preparation method of nano-fluorosilicon-doped hydroxyapatite, including the following steps:

[0067] S1. Weigh 2125.35 g of calcium nitrate tetrahydrate and dissolve it in 3 L of pure water.

[0068] S2. Weigh 53.33 g of tetraethoxysilane and add it to the reaction kettle. Rinse the beaker 3 times with a total of 5 L of pure water, and add the rinsing solution to the reaction kettle.

[0069] S3. Weigh 679.32 g of diammonium hydrogen phosphate and 2.22 g of ammonium fluoride, dissolve the above materials in 15 L of pure water to obtain a mixed solution.

[0070] The mass ratio of calcium nitrate tetrahydrate, tetraethoxysilane, diammonium hydrogen phosphate, and ammonium fluoride is 39.9:1:12.7:0.04.

[0071] S4. Heat the solution in the reaction kettle in step S2 to 88 °C and stir for 2 h; then add the calcium nitrate tetrahydrate solution prepared in step S1 to the reaction kettle, supplement pure water until the liquid level in the reaction kettle reaches 20 L, add 3500 mL of ammonia water, and continue to stir for 3 h.

[0072] S5. After stirring is completed, add dropwise the mixed solution prepared in step S3 to the reaction kettle, and at the same time add dropwise 1500 mL of ammonia water, and the ammonia water ends dropping before the mixed solution prepared in step S3 is completely added dropwise; continue to stir for 3 h, age for 12 h, then wash and discard the supernatant, and collect the precipitate to obtain nano-fluorosilicon-doped hydroxyapatite powder.

[0073] Example 3

[0074] This example provides a preparation method for a bioactive filler for anti-sensitivity toothpaste, including the following steps:

[0075] S1. Prepare triclinic calcium phosphate for standby. The preparation method of triclinic calcium phosphate is as shown in Example 1 and will not be elaborated here.

[0076] S2. Prepare nano-fluorosilicon-doped hydroxyapatite for standby. The preparation method of nano-fluorosilicon-doped hydroxyapatite is as shown in Example 2 and will not be elaborated here.

[0077] S3. Mix the nano-fluorosilicon-doped hydroxyapatite prepared in step S2 and the triclinic calcium phosphate prepared in step S1 according to a mass ratio of 20:80, and fully stir to obtain a mixed powder, which is the bioactive filler for anti-sensitivity toothpaste.

[0078] Example 4 and Comparative Example 1

[0079] Example 4 and Comparative Example 1 respectively provide a preparation method for a bioactive filler for anti-sensitivity toothpaste. Compared with Example 3, the only difference is that the mass ratio of nano-fluorosilicon-doped hydroxyapatite and triclinic calcium phosphate in step S3 is changed, and other experimental steps and parameters are the same and will not be elaborated here. The mass ratios of the corresponding nano-fluorosilicon-doped hydroxyapatite and triclinic calcium phosphate in Examples 1 to 4 and Comparative Example 1 are shown in Table 1.

[0080] Table 1 Mass ratios of the corresponding nano-fluorosilicon-doped hydroxyapatite and triclinic calcium phosphate in Examples 1 to 4 and Comparative Example 1

[0081] Number Mass ratio of nano-fluorosilicon-doped hydroxyapatite and tricalcium phosphate Example 1 0:100 Example 2 100:0 Example 3 20:80 Example 4 10:90 Comparative Example 1 30:70

[0082] Examples 5 - 6 and Comparative Examples 2 - 4

[0083] Examples 5 - 6 and Comparative Examples 2 - 4 respectively provide a method for treating dentin samples with toothpaste samples. In Examples 5 - 6 and Comparative Example 2, the toothpaste samples are prepared by mixing the bioactive fillers of the anti - sensitive toothpaste prepared in Examples 3 - 4 and Comparative Example 1 with a certain commercially available ordinary toothpaste without anti - sensitive effect in a ratio of 5:95. In Comparative Examples 3 - 4, the toothpaste samples are respectively bioactive fillers prepared by mixing commercially available nano - hydroxyapatite with tricalcium phosphate or brushite in a mass ratio of 20:80, and mixing with the above - mentioned ordinary toothpaste without anti - sensitive effect in a ratio of 5:95, as shown in Table 2.

[0084] Table 2 Toothpaste sample categories corresponding to Examples 5 - 6 and Comparative Examples 2 - 4

[0085] Number Toothpaste sample category Example 5 Nano-fluorosilicon-doped hydroxyapatite / tricalcium phosphate (20:80) + ordinary toothpaste Example 6 Nano-fluorosilicon-doped hydroxyapatite / tricalcium phosphate (10:90) + ordinary toothpaste Comparative Example 2 Nano-fluorosilicon-doped hydroxyapatite / tricalcium phosphate (30:70) + ordinary toothpaste Comparative Example 3 Nano-hydroxyapatite / tricalcium phosphate (20:80) + ordinary toothpaste Comparative Example 4 Nano-hydroxyapatite / brushite (20:80) + ordinary toothpaste

[0086] The specific operation is as follows: The bovine teeth are thoroughly cleaned and placed in a 0.5 wt% thymol aqueous solution. Use a low - speed diamond cutter (SYJ - 160 low - speed diamond cutter) to prepare dentin slices with a thickness of 2 mm, and then polish them with silicon carbide water sandpapers of 200, 400, 1000, 2000, and 4000 meshes until the surface is bright and flat; finally, polish the dentin slices smooth with 3M polishing paper (3 microns), and ultrasonically clean them in deionized water for 3 min for standby. Before use, place the dentin slices in a 36 wt% phosphoric acid aqueous solution for demineralization treatment for 2 min, then rinse them with deionized water for 3 min, take out 3 dentin slices as samples before toothpaste treatment for characterization analysis, and randomly divide the remaining ones into 5 groups, with 6 slices in each group. The dentin slices are fixed in the oral elastomer material with the dentin surface facing up.

[0087] The specific steps for treating dentin samples with toothpaste samples are as follows: Prepare a slurry according to toothpaste sample: water = 1:2; place the dentin slices in the slurry and brush them with an electric toothbrush for 20 s, then rinse them with 20 mL of deionized water for 10 s and soak them in 20 ml of simulated oral saliva; then place the container containing the simulated oral saliva and the dentin slices in a constant - temperature oscillator at 37 °C with a constant rate of 150 rpm for 4 h. Treat the dentin samples 2 times a day, and after the second treatment, leave them overnight in the 37 °C simulated oral saliva. When the number of treated samples is 6 times, take out the dentin samples, dry them and store them for scanning electron microscope observation.

[0088] After conducting experiments according to the preparation methods provided in each example and comparative example, it can be found that the change in the mass ratio of nano-fluorosilicon-doped hydroxyapatite to tricalcium phosphate has a greater impact on the performance of the bioactive filler of the anti-sensitivity toothpaste. The electron microscope morphology of the tricalcium phosphate obtained in Example 1 was characterized, and the results are as Figure 1 shown. From Figure 1 it can be seen that the morphology of tricalcium phosphate is a lamellar structure with a thickness at the nanometer level, and the lamellar structure is about a dozen micrometers. The microstructure of tricalcium phosphate powder is a lamellar crystal with a width of 0.5 - 1.5 μm and a length of 2 - 5 μm. The diameter of the dentinal tubules we know is about a dozen micrometers, and a part of the pure tricalcium phosphate with a lamellar structure has a certain probability of blocking the dentinal tubules. The electron microscope morphology of the nano-fluorosilicon-doped hydroxyapatite obtained in Example 2 was characterized, and the results are as Figure 2 shown. From Figure 2 it can be seen that the nano-fluorosilicon-doped hydroxyapatite is at the nanometer level with a particle size of 70 - 120 nm. The nano-scale fluorosilicon-doped hydroxyapatite is more conducive to filling the dentinal tubules. The microstructure of the bioactive filler of the anti-sensitivity toothpaste with a mass ratio of nano-fluorosilicon-doped hydroxyapatite to tricalcium phosphate of 10:90 obtained in Example 4 was characterized, and the results are as Figure 3 shown. The XRD results were compared with the standard card (calcium hydrogen phosphate, triclinic system), and obvious characteristic peaks of tricalcium hydrogen phosphate (tricalcium phosphate) were shown, indicating that the main component of each sample is tricalcium phosphate. As shown by the infrared spectrum, there are absorption peaks at 3426 cm -1 , 1363 cm -1 , 1130 cm -1 , 1067 cm -1 , 1004 cm -1 , 906 cm -1 , 579 cm -1 . Comparing with the standard spectrum of calcium hydrogen phosphate, it shows that the three batches of samples all have obvious calcium hydrogen phosphate characteristics and no other impurity peaks, indicating that the main component of each sample is calcium hydrogen phosphate (tricalcium phosphate).

[0089] The electron microscope morphology diagrams of the toothpaste samples provided in Examples 5 - 6 and Comparative Examples 2 - 4 for blocking dentinal tubules were characterized, and the results are as Figure 4 shown. From Figure 4 it can be seen that the toothpaste samples containing nano-fluorosilicon-doped hydroxyapatite (F / Si-HA) and tricalcium phosphate have the best effect on blocking dentinal tubules. In particular, the effects of Examples 5 and 6 are the most obvious, indicating that the mass ratio of nano-fluorosilicon-doped hydroxyapatite to tricalcium phosphate in the range of (0 - 20):(80 - 100) has the best effect. The filling rates of the toothpaste samples provided in Examples 5 - 6 and Comparative Examples 2 - 4 for blocking dentinal tubules were characterized, and the results are as Figure 5 shown. FromFigure 5 It can be seen that the filling rates of the toothpaste samples in Examples 5 and 6 are close to 100%, showing a significant increase compared to the toothpaste samples containing nano-hydroxyapatite / tri-calcium phosphate and nano-hydroxyapatite / brushite.

[0090] In summary, the anti-sensitivity toothpaste bioactive filler and its preparation method provided by the present invention have the advantages of effectively improving dental caries and fundamentally eliminating dentin hypersensitivity symptoms, and can be used for the care of dentin hypersensitivity.

[0091] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. Preparation method of bioactive filler for anti - sensitivity toothpaste It is characterized in that it includes the following steps: S1. Prepare tricalcium phosphate for standby; S2. Prepare nano - fluorosilicon - doped hydroxyapatite for standby; S3. Mix the tricalcium phosphate prepared in step S1 and the nano - fluorosilicon - doped hydroxyapatite prepared in step S2 according to a preset mass ratio, and obtain a mixed powder after sufficient stirring, which is the bioactive filler for anti - sensitivity toothpaste.

2. The preparation method of the bioactive filler for anti - sensitivity toothpaste according to claim 1, it is characterized in that in step S1, the preparation method of the tricalcium phosphate includes the following steps: S11. Prepare a calcium acetate solution for standby; S12. Prepare a dilute phosphoric acid solution according to a preset mass ratio of calcium acetate to phosphoric acid for standby; S13. Stir and heat the calcium acetate solution prepared in step S11, and then add acetic acid, and obtain a mixed solution after sufficient stirring; S14. Add the dilute phosphoric acid solution prepared in step S12 to the mixed solution in step S13 for reaction, filter and wash after the reaction is completed, and spray - dry to obtain tricalcium phosphate powder.

3. The preparation method of the bioactive filler for anti - sensitivity toothpaste according to claim 1, it is characterized in that in step S2, the preparation method of the nano - fluorosilicon - doped hydroxyapatite includes the following steps: S21. Prepare a calcium nitrate tetrahydrate solution for standby; S22. Prepare a tetraethoxysilane solution for standby; S23. Prepare a mixed solution of diammonium hydrogen phosphate and ammonium fluoride for standby; S24. Add the tetraethoxysilane solution prepared in step S22 to the reaction kettle, heat and stir; then add the calcium nitrate tetrahydrate solution prepared in step S21 to the reaction kettle, add ammonia water, and stir for 3 h; S25. After the stirring is completed, dropwise add the mixed solution of diammonium hydrogen phosphate and ammonium fluoride prepared in step S23 to the reaction kettle, and at the same time dropwise add ammonia water, and the ammonia water ends dropping before the mixed solution of diammonium hydrogen phosphate and ammonium fluoride prepared in step S23 is completely dropped; continue to stir for 3 h, age, wash and remove the supernatant, and collect the precipitate to obtain nano - fluorosilicon - doped hydroxyapatite powder.

4. The preparation method of the bioactive filler for anti - sensitivity toothpaste according to claim 1, it is characterized in that in step S3, the preset mass ratio of nano - fluorosilicon - doped hydroxyapatite to tricalcium phosphate is (0 - 20):(80 - 100).

5. The preparation method of the bioactive filler for anti - sensitivity toothpaste according to claim 2, it is characterized in that in step S12, the mass ratio of calcium acetate to phosphoric acid is (1 - 2):

1.

6. The preparation method of the bioactive filler for anti - sensitivity toothpaste according to claim 2, it is characterized in that in step S13, the heating temperature is 60 - 70 °C, and the addition amount of acetic acid is 0 - 20 g.

7. The preparation method of the bioactive filler for anti - sensitivity toothpaste according to claim 2, it is characterized in that in step S14, the reaction temperature is 60 - 70 °C, and the reaction time is 2 - 4 h.

8. The preparation method of the bioactive filler for anti - sensitivity toothpaste according to claim 3, it is characterized in that In step S24, the heating temperature is 80 to 90 °C; in step S25, the aging time is at least 12 h.

9. The method for preparing the bioactive filler for anti-sensitivity toothpaste according to claim 3, characterized in that in the method for preparing nano-fluorosilicon-doped hydroxyapatite, the mass ratio of calcium nitrate tetrahydrate, tetraethoxysilane, diammonium hydrogen phosphate, and ammonium fluoride is (38 to 42):(0.8 to 1.2):(12 to 14):(0.03 to 0.05).

10. A bioactive filler for anti-sensitivity toothpaste, characterized in that the bioactive filler for anti-sensitivity toothpaste is prepared by the method for preparing the bioactive filler for anti-sensitivity toothpaste according to any one of claims 1 to 9.

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