Tooth wear evaluation model for evaluating safety of oral product as well as preparation method and application of tooth wear evaluation model

Abstract

The invention discloses a tooth wear evaluation model for evaluating the safety of oral products and a preparation method and application thereof. The tooth wear evaluation model is at least obtained by grinding and polishing the surface of a tooth model, and the tooth model comprises at least one of an animal enamel block model, an animal dentin block model, a tooth-like material dental film model, a full-mouth animal enamel model and a tooth-like material full-mouth tooth model. According to the tooth wear evaluation model, the wear performance of the oral product can be conveniently tested in vitro.

Description

Technical Field

[0001] The present application relates to the field of oral cleaning technology, and in particular to a tooth wear assessment model for evaluating the safety of oral products, and a preparation method and application thereof. Background Art

[0002] Teeth are essential organs of mastication, constantly subjected to cyclical chewing loads throughout a person's life. Therefore, friction and wear of teeth are an inevitable process in the oral cavity, primarily occurring on the tooth's outer protective layer—the enamel surface. Excessive tooth wear can not only lead to poor tooth appearance, dentin hypersensitivity, chewing dysfunction, and even temporomandibular joint disorders, but the resulting cracks may also extend into the dentin, leading to severe pulpitis.

[0003] Oral products such as toothbrushes, electric toothbrushes, and toothpaste are among the most widely used products for daily oral care and the treatment of various oral diseases. The physical friction generated by toothbrushes and toothpaste can also cause wear and tear on the hard tissues of the teeth. Long-term improper use of oral products, such as brushing method, strength, brushing time, brushing frequency, brush head type, bristle hardness, and different toothpastes, may cause irreparable wear and tear on teeth.

[0004] Therefore, there is an urgent need for a product or method that can be used to evaluate the abrasive effect of different oral products or different usage methods of oral products (brushing force, brushing speed, brushing time, etc.) on teeth. Summary of the Invention

[0005] The purpose of this application is to provide a tooth wear assessment model for evaluating the safety of oral products, as well as its preparation method and application.

[0006] This application adopts the following technical solutions:

[0007] The first aspect of the present application discloses a tooth wear assessment model for evaluating the safety of oral products, wherein the tooth wear assessment model is obtained by at least grinding and polishing the surface of a tooth model, wherein the tooth model includes at least one of an animal enamel block model, an animal dentin block model, a tooth slice model made of a tooth-like material, a full-mouth animal enamel model, and a full-mouth tooth model made of a tooth-like material. It should be noted that in the present application, by grinding and polishing the tooth model, the surface flatness of each tooth model can be increased, which can reduce the difference between samples when performing wear testing on oral products in vitro. In addition, the high surface flatness of the tooth model can facilitate the characterization of the wear condition.

[0008] In one implementation of the present application, the tooth model includes at least one of an animal enamel block model, an animal dentin block model, and a tooth-like material tooth film model. It should be noted that the animal enamel block can refer to an enamel block sample made from the teeth of humans or other animals, which can be used to evaluate the abrasive effects of oral products on enamel; the animal dentin block can refer to a dentin block sample made from the teeth of humans or other animals. At present, the effects of external wear such as brushing on dentin erosion have not been fully elucidated. Therefore, a model made from a dentin block can be used to evaluate the abrasive effects of oral products on dentin; and the tooth-like material tooth film can refer to a tooth film model made from a tooth-like material (such as hydroxyapatite). The composition and physical and chemical properties of hydroxyapatite and teeth are very similar. First, the chemical composition of hydroxyapatite is very similar to calcium phosphate, the main component of tooth tissue. Calcium phosphate in teeth mainly exists in the form of hydroxyapatite. Second, hydroxyapatite and teeth are both porous materials containing a large number of micropores and microstructures, which can promote healing and tissue regeneration in organisms.

[0009] It should also be noted that when using human or other animal tooth samples, the morphology, size, and structure of enamel blocks from different people or populations vary, resulting in a lack of consistency when used to make models for testing. This makes it difficult to replicate or compare test results across batches, which can significantly impact the assessment of the wear process. Using tooth-like materials to prepare tooth models facilitates mass production. For example, hydroxyapatite sheets can be mass-produced in industrial production, are relatively simple to operate, and are readily available in large quantities, making them suitable for promotion in multiple application scenarios. The resulting tooth models are stable, reproducible, and less susceptible to human and other environmental factors, making the statistical differences in the results more pronounced. Therefore, the assessment of the wear and remineralization process is more easily correlated with core technical parameters, enabling optimization of technical parameters during the R&D process. It is also more suitable for cross-product comparisons, thereby establishing a clear baseline for wear assessment. It should also be noted that using enamel blocks, dentin blocks, or tooth-like material sheets for wear assessment can simplify teeth into flat enamel blocks, simulating internal or external wear on the surface of the enamel blocks to assess wear. This method has the advantages of simplicity and efficiency.

[0010] In one implementation of the present application, the tooth model includes at least one of a full-mouth animal enamel model and a full-mouth tooth model made of tooth-like materials. It should be noted that the full-mouth animal enamel model may refer to the collected teeth of humans or other animals (which may include incisors, canines, and molars), which are cleaned, ground, and polished, and then inlaid on a false gum material (which can be made by 3D printing, and the material is resin) according to the real tooth distribution to simulate the real tooth distribution and obtain a full-mouth tooth model. The full-mouth tooth model made of tooth-like materials may refer to teeth made of tooth-like materials (such as hydroxyapatite) through tooth molds (which can be downloaded from a tooth model database to simulate the real tooth arrangement). The gum material can be made by 3D printing using resin to obtain a full-mouth tooth model made of tooth-like materials that simulates the real tooth distribution. It should also be noted that the use of a full-mouth animal enamel model or a full-mouth tooth model made of tooth-like materials for wear testing can take into account the wear effects of the actual arrangement of teeth, the gaps between teeth, the depth of the gingival margin, the curvature and grooves of the teeth themselves, etc., and can simulate the wear of full-mouth teeth under real conditions; in addition, the use of a full-mouth tooth model for wear testing can also simulate the wear of teeth caused by different brushing methods (including but not limited to the Bass brushing method, the Roche brushing method, the circular brushing method, and the horizontal vibrating brushing method); in addition, different full-mouth tooth models can be customized according to different populations (such as children, teenagers, adults, the elderly, etc.) to test the tooth wear of different populations.

[0011] In one implementation of the present application, the height deviation of each position on the surface of the tooth wear assessment model is less than or equal to 0.02 mm. It should be noted that after fine processing of grinding and polishing the tooth model, the undulation difference at any position (i.e., the height difference between two adjacent points) does not exceed 0.2 mm. In other words, if two adjacent points are arbitrarily selected on the surface of the model for measurement, the absolute value of the vertical height difference between them will not exceed 0.2 mm. In this case, the surfaces of each tooth wear assessment model are relatively uniform and have a high degree of flatness, which can be beneficial to improving the uniformity of the test.

[0012] In one implementation of the present application, the oral product includes an oral care product and an oral fixture, wherein the oral care product includes at least one of toothpaste, mouthwash, tooth powder, a toothbrush, an electric toothbrush, an oral irrigator and dental floss, and the oral fixture includes sandblasting.

[0013] In one implementation of the present application, the tooth wear assessment model is also obtained by subjecting the tooth model to acid etching, wherein the acid etching comprises: contacting the tooth model with an acidic solution for a predetermined time. It should be noted that, under physiological conditions, due to the effects of endogenous acids or bacteria during the intake of acidic foods and beverages and the reflux process, the teeth are in an acidic environment, and the teeth may be demineralized to varying degrees, and the inorganic hydroxyapatite crystals, organic proteins and lipids in the enamel are dissolved, resulting in enamel corrosion and softening. The tooth wear assessment model of the present application is subjected to acid etching treatment, and the acid etching treatment can simulate the acid production in the mouth under endogenous or exogenous conditions. The tooth wear assessment model after acid etching is used to perform in vitro testing on oral products, which can further simulate the overall alternating evolution law of the actual oral environment, fully consider the dynamic law of enamel corrosion demineralization and remineralization repair, and study and evaluate the enamel damage caused by external physical factors in the context of physiological function, which can help improve the scientificity and accuracy of the method.

[0014] In one implementation of the present application, the surface of the tooth model is first ground and polished, and then acid-etched.

[0015] In one implementation of the present application, the tooth model can be completely immersed in the acidic solution.

[0016] In one implementation of the present application, during the acid etching treatment, the pH of the acidic solution is 1 to 6. It should be noted that, for example, the pH of the acidic solution can be 1, 2, 3, 4, 5, or 6, thereby simulating the local microenvironment of consuming acidic substances, acid regurgitation, or bacterial acid production during eating, thereby obtaining a tooth model after acid etching.

[0017] In one implementation of the present application, the acidic solution is at least one of a lactic acid solution, an acetic acid solution, and a citric acid solution.

[0018] In one implementation of the present application, the acid etching treatment lasts for 10 to 120 minutes.

[0019] The second aspect of the present application discloses a method for preparing a tooth wear assessment model for evaluating the safety of oral products, which is characterized in that it includes: grinding and polishing the surface of the tooth model to obtain the tooth wear assessment model, wherein the tooth model includes at least one of an animal enamel block model, an animal dentin block model, a tooth-like material tooth film model, a full-mouth animal enamel model, and a full-mouth tooth model of tooth-like material.

[0020] In one implementation of the present application, the tooth model includes at least one of an animal enamel block model, an animal dentin block model, and a tooth film model made of a tooth-like material.

[0021] In one implementation of the present application, the tooth model includes at least one of a full-mouth animal enamel model and a full-mouth tooth model made of tooth-like materials.

[0022] In one implementation of the present application, the grinding and polishing include: wet grinding using #400 to #5000 grit sandpaper and / or 400 to 5000 grit silicon carbide paper; or also include polishing using a polishing liquid with a cerium oxide concentration of 80 g / L.

[0023] In one implementation of the present application, the preparation method includes: grinding and polishing the surface of the tooth model, and then performing acid etching on the tooth model to obtain the tooth wear assessment model; wherein, the acid etching treatment includes: contacting the tooth model with an acidic solution for a predetermined time.

[0024] In one implementation of the present application, the tooth model can be completely immersed in the acidic solution.

[0025] In one implementation of the present application, during the acid etching treatment, the pH of the acidic solution is 1 to 6.

[0026] In one implementation of the present application, the acidic solution is at least one of a lactic acid solution, an acetic acid solution, and a citric acid solution.

[0027] In one implementation of the present application, the acid etching treatment lasts for 10 to 120 minutes.

[0028] The third aspect of the present application discloses an application of the tooth wear assessment model as mentioned in the first aspect of the present application in assessing the safety of oral products.

[0029] One implementation of the present application includes performing a wear test using the tooth wear assessment model; the wear test includes: subjecting the oral product to contact friction treatment on the tooth wear assessment model, and recording the wear condition of the surface of the tooth wear assessment model before and after the contact friction treatment.

[0030] In one implementation of the present application, after the oral product performs contact friction treatment on the tooth wear assessment model, the surface of the tooth wear assessment model is wiped with anhydrous ethanol. This can help reduce the interference of debris dropped during brushing on the wear condition of the tooth wear assessment model surface.

[0031] In one implementation of the present application, the oral product is a toothbrush or an electric toothbrush, and the wear test includes: fixing the tooth wear assessment model to a test bench, and using a three-dimensionally movable robotic arm to control the oral product to perform contact friction on the tooth wear assessment model. It should be noted that using a robotic arm to control the oral product can help improve test consistency and facilitate comparison of wear conditions under different conditions.

[0032] In one implementation of the present application, a robotic arm control system stores or inputs different brushing parameters. The robotic arm control system controls the robotic arm to grip the oral product and cause the oral product to perform contact friction processing on the tooth wear assessment model according to the preset brushing parameters. It should be noted that in this case, automated testing can be performed, improving test efficiency and consistency.

[0033] In one implementation of the present application, the brushing parameters include at least one of a movement path, a brushing angle, a brushing force, a brushing speed, and a brushing time. It should be noted that in this case, different brushing methods (e.g., the Bass method, the Roche method, the circular brushing method, the horizontal vibration brushing method) or the brushing habits of different groups of people can be set as different brushing parameters to test the effects of different brushing methods or brushing patterns on teeth, thereby evaluating the wear of the tooth wear assessment model under different brushing conditions.

[0034] In one implementation of the present application, the brushing angle is selected in the range of 0° to 90°. Preferably, the brushing angle is selected in the range of 20° to 90°. It should be noted that the brushing angle refers to the angle between the toothbrush bristles and the tooth surface. It is currently believed that the ideal brushing angle is 45°, which can help clean the tooth surface and the gaps between the teeth and gums at the same time. In the present application, different brushing angles can be selected to evaluate the wear of different parts of the teeth caused by different brushing angles.

[0035] In one implementation of the present application, the brushing force is selected in a range of 0g to 100g. It should be noted that brushing force refers to the pressure of the toothbrush bristles against the teeth. By selecting different brushing pressures, the wear of the teeth caused by different brushing pressures can be tested.

[0036] In one implementation of the present application, the brushing speed is selected in a range of 0 mm / s to 50 mm / s. It should be noted that the brushing speed refers to the speed at which the toothbrush moves.

[0037] In one implementation of the present application, the oral product is an electric toothbrush, and the electric toothbrush is used to perform contact friction treatment on the tooth wear assessment model, with a brushing pressure of 100g to 400g, a brushing speed of 2mm / s to 30mm / s, and a brushing time of 30 hours to 300 hours. It should be noted that the brushing time of 30 hours to 300 hours is equivalent to a person actually brushing their teeth for 4 to 50 years. By conducting an accelerated aging experiment on the tooth model, the wear of the oral product under long-term use can be tested. The brushing pressure is 100g to 400g, and the brushing speed is 2mm / s to 30mm / s, which are similar to the actual brushing force and speed of humans. By simulating the actual brushing situation of humans and conducting accelerated aging experiments, it is beneficial to evaluate the wear performance of oral products under the real brushing method of humans.

[0038] In one implementation of the present application, the vibration frequency of the electric toothbrush is 50 Hz to 500 Hz, and the rotation speed is 4000 rpm to 60000 rpm. Thus, the wear condition under different vibration frequencies or different rotation speeds can be tested.

[0039] In one implementation of the present application, in the wear test, the brushing speed, brushing rate, and brushing time of the electric toothbrush are all the same, but the vibration frequency or rotation speed is different, so as to evaluate the tooth wear effect of electric toothbrushes with different frequencies or rotation speeds. In this way, by controlling the variables, the tooth wear effect of electric toothbrushes with different frequencies or rotation speeds can be evaluated.

[0040] In one implementation of the present application, when the tooth wear assessment model is subjected to contact friction treatment using the oral product, the tooth wear assessment model is immersed in a liquid medium, and the liquid medium is circulated. It should be noted that the liquid medium can be water, or a toothpaste suspension, mouthwash, etc., which can be determined according to experimental requirements. The circulated supply can help prevent the volatilization of the liquid medium, so that the tooth wear assessment model is always immersed in the liquid medium during the test.

[0041] In one implementation of the present application, after the wear test, a remineralization and repair test is also included; the remineralization and repair test includes: exposing the tooth wear assessment model to artificial saliva for remineralization and repair treatment, and recording the wear conditions on the surface of the tooth wear assessment model before and after the remineralization and repair treatment. It should be noted that tooth enamel is a hard, acellular, avascular tissue composed of 96% to 97% inorganic minerals, 3% water, and 1% organic matrix, and has no regenerative ability. The inorganic mineral component of mature tooth enamel is a mixture of various compounds, mainly hydroxyapatite (HA). Therefore, biological remineralization of the enamel surface is crucial for teeth. Early enamel demineralization can be reversed by calcium and phosphate in saliva, that is, biological remineralization of enamel. Calcium and phosphate ions passively enter the demineralized tooth enamel from saliva, and the affected tooth enamel begins to remineralize. Under physiological conditions, tooth enamel also undergoes a remineralization and repair process after experiencing mechanical wear. The application of the tooth wear assessment model of the present application in evaluating the safety of oral products takes into account the overall alternating evolution law of the actual oral environment, simulates the wear part, and takes into account the remineralization situation, which is highly consistent with the actual situation in the oral cavity. Therefore, it can help improve the scientificity and accuracy of the method.

[0042] In one implementation of the present application, the remineralization and repair treatment lasts for 7 to 30 days, thereby fully considering the overall alternating evolution of the actual oral environment and improving the scientificity and accuracy of the method.

[0043] In one implementation of the present application, the pH of the artificial saliva is 5.6 to 7.6.

[0044] In one implementation of the present application, the artificial saliva contains 0.55 mmol / L to 2.825 mmol / L of calcium. It should be noted that the calcium in the artificial saliva may refer to free Ca 2+ , inorganic complexes such as calcium phosphates, and calcium forms bound to organic matter (such as proteins, carbohydrates, etc.).

[0045] In one implementation of the present application, the artificial saliva contains phosphate. The phosphate may be at least one of dibasic calcium phosphate, octacalcium phosphate, calcium phosphate, and hydroxyapatite. It should be noted that these calcium phosphates can promote remineralization of tooth surfaces. The concentration of phosphate in the artificial saliva is 0.5 to 1.5 mmol / L.

[0046] In one implementation of the present application, the temperature during the remineralization and repair treatment is 36 to 38° C. Preferably, the temperature during the remineralization and repair treatment is 37° C. Thus, the remineralization process at the actual oral temperature of the human body can be simulated.

[0047] In one implementation of the present application, the wear condition of the surface of the tooth wear assessment model includes at least one of the wear volume loss, surface defect height, surface roughness and nano-microhardness of the surface of the tooth wear assessment model.

[0048] In one implementation of the present application, the wear condition of the surface of the tooth wear evaluation model is measured using at least one of a white light interferometer, a scanning electron microscope, a nanoindenter, a three-dimensional surface topography instrument, an atomic force microscope, an X-ray diffractometer, and a scratch tester. It should be noted that in the wear test, a white light interferometer (Up series, Rtecinstruments Inc, USA) can be used to scan the trajectory before and after wear, and the wear volume loss can be measured using corresponding software. Qualitative and quantitative characterization results such as a three-dimensional topography image, surface defect height, defect size distribution, and surface roughness can be obtained to achieve the measurement of the three-dimensional surface morphology of the tooth model evaluation model before and after wear. After the wear test, the trajectory changes of each sample before and after wear can be preliminarily observed by a stereo microscope. A representative sample of each group is pasted on a conductive adhesive, the sample is sputter-plated with gold, and a scanning electron microscope (SEM, Inspect F50, FEI, Hillsboro, OR, USA) is observed at a relatively low speed under a high vacuum of 20kV to achieve the measurement of the surface morphology of the tooth model evaluation model before and after wear. Nanoindentation measurements can be performed using a nanoindenter from Anton Paar Italia srl ​​Rivoli 10098, Italy. This indenter features a UNHT head with a diamond Berkovich tip. It can be set to a maximum load of 5 mN, an up / down rate of 10 mN / min, and a maximum load dwell time of 10 s. This allows for the measurement of nanohardness of tooth models before and after wear. It should also be noted that during remineralization testing, the worn area can be re-scanned using a 3D surface topography analyzer or atomic force microscope. A constant reference point is selected to measure the amount of enamel surface crystals and surface roughness within the target area. Data from each observation point is combined to form a curve of the amount of repair, which can be used to evaluate the ability of saliva to repair enamel damage. Scanning electron microscopy can be used to observe the enamel surface repair morphology. XRD can be used to analyze the type and size of the deposited crystals. EDX can be used to analyze the elemental composition of the crystals. Scratch testing can be used to verify the bonding of the deposited crystals. The nanoindenter can also be used to determine the hardness and modulus of the enamel repair layer.

[0049] In one implementation of the present application, the wear rate of the oral product on the tooth wear assessment model is calculated based on the wear condition of the tooth wear assessment model surface to assess the safety of the oral product. Thus, the wear performance of different oral products or different usage methods of oral products can be assessed based on the wear rate caused by different oral products or different usage methods on the tooth wear assessment model.

[0050] In one implementation of the present application, when the wear rate or damage amount caused by external wear is less than the remineralization rate or the growth amount of remineralized crystals, it is considered that this external action mode will not cause adverse effects on personal oral health problems; when the wear rate or damage amount caused by external mechanical factors is greater than the remineralization rate or the growth amount of remineralized crystals, it is considered that this external action mode will cause irreversible damage to personal oral health and a warning should be given.

[0051] In one implementation of the present application, for the tooth wear assessment model, if the difference in surface defects before wear and after remineralization and restoration is greater than 10 μm, and the difference in defect size distribution before wear and after remineralization and restoration is greater than or equal to 5 μm, and the difference in surface roughness before wear and after remineralization and restoration is greater than or equal to 1 μm, then the oral product has caused serious irreversible damage to the tooth model.

[0052] In one implementation of the present application, for the tooth wear assessment model, if the difference in surface defects before wear and after remineralization and restoration is 5 μm to 10 μm, and the difference in defect size distribution before wear and after remineralization and restoration is 1 μm to 5 μm, and the difference in surface roughness before wear and after remineralization and restoration is less than 1 μm, then the oral product has a risk of irreversible damage to the tooth model, and if wear continues, serious irreversible damage may be caused.

[0053] In one implementation of the present application, for the tooth wear assessment model, if the difference in surface defects before wear and after remineralization and restoration is 1 μm to 5 μm, and the difference in defect size distribution before wear and after remineralization and restoration is 1 μm to 5 μm, and the difference in surface roughness before wear and after remineralization and restoration is less than 1 μm, then the oral product poses a risk of damage to the tooth model, and if wear continues, irreversible damage may be caused.

[0054] In one implementation of the present application, for the tooth wear assessment model, if the difference in surface defect height before wear and after remineralization and restoration is less than 1 μm, and the difference in defect size distribution before wear and after remineralization and restoration is less than 1 μm, and the difference in surface roughness before wear and after remineralization and restoration is less than 1 μm, then the oral product poses no health risk to the tooth model.

[0055] The beneficial effects of this application are:

[0056] The tooth wear assessment model for evaluating the safety of oral products disclosed in the present application, as well as its preparation method and application, can facilitate in vitro testing of the wear performance of oral products. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 These are stereo microscope surface photographs of the tooth model before and after being worn using sample No. 1 according to Example 4 of the present application.

[0058] Figure 2 These are stereo microscope surface photographs of the tooth model before and after being worn using sample No. 5 involved in Example 4 of the present application.

[0059] Figure 3 These are stereo microscope surface photographs of the tooth model before and after being worn using sample No. 10 involved in Example 4 of the present application.

[0060] Figure 4 These are stereo microscope surface photographs of the tooth model before and after abrasion using sample No. 15 involved in Example 4 of the present application.

[0061] Figure 5 These are stereo microscope surface photographs of the tooth model before and after being worn using sample No. 20 involved in Example 4 of the present application.

[0062] Figure 6 This is a scanning electron microscope image of the tooth model before and after being worn using sample No. 1 involved in Example 4 of the present application.

[0063] Figure 7 This is a scanning electron microscope image of the tooth model before and after being worn using sample No. 5 involved in Example 4 of the present application.

[0064] Figure 8 This is a scanning electron microscope image of the tooth model before and after being worn using sample No. 10 involved in Example 4 of the present application.

[0065] Figure 9 This is a scanning electron microscope image of the tooth model before and after being worn using sample No. 15 involved in Example 4 of the present application.

[0066] Figure 10 This is a scanning electron microscope image of the tooth model before and after being worn using sample No. 20 involved in Example 4 of the present application.

[0067] Figure 11This is an analysis diagram of the three-dimensional morphology, surface defect height, defect size distribution and surface roughness of the tooth model before and after wear using sample No. 1 involved in Example 4 of the present application.

[0068] Figure 12 This is an analysis diagram of the three-dimensional morphology, surface defect height, defect size distribution and surface roughness of the tooth model before and after wear using sample No. 5 involved in Example 4 of the present application.

[0069] Figure 13 This is an analysis diagram of the three-dimensional morphology, surface defect height, defect size distribution and surface roughness of the tooth model before and after wear using sample No. 10 involved in Example 4 of the present application.

[0070] Figure 14 This is an analysis diagram of the three-dimensional morphology, surface defect height, defect size distribution and surface roughness of the tooth model before and after wear using sample No. 15 involved in Example 4 of the present application.

[0071] Figure 15 This is an analysis diagram of the three-dimensional morphology, surface defect height, defect size distribution and surface roughness of the tooth model before and after wear using sample No. 20 involved in Example 4 of the present application. DETAILED DESCRIPTION

[0072] The present invention is further described in detail below by specific embodiments in conjunction with the accompanying drawings. In the following embodiments, many detailed descriptions are intended to enable the present application to be better understood. However, those skilled in the art can readily appreciate that some of the features may be omitted in different circumstances, or may be replaced by other materials or methods. In some cases, some operations related to the present application are not shown or described in the specification. This is to avoid the core of the present application being overwhelmed by excessive descriptions, and for those skilled in the art, it is not necessary to describe these related operations in detail. They can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0073] In addition, the features, operations, or characteristics described in the specification may be combined in any appropriate manner to form various embodiments. Furthermore, the steps or actions in the method description may be reordered or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various sequences in the specification and drawings are provided solely for the purpose of clearly describing a particular embodiment and are not intended to be mandatory, unless otherwise specified.

[0074] In response to the problem that there is currently no method for evaluating the tooth wear effect of oral products in the prior art, this application creatively proposes a tooth wear assessment model for evaluating the safety of oral products, as well as its preparation method and application. This application has the following advantages:

[0075] Tooth enamel damage testing cannot be performed on humans and can only be achieved through in vitro simulation. In this application, by grinding and polishing the tooth model to make the surface of the tooth model more flat, the resulting tooth wear assessment model can be used to perform wear testing on oral products in vitro.

[0076] Tooth models can include at least one of animal enamel block models, animal dentin block models, and tooth-like material film models, enabling testing of enamel and dentin wear. Animal tooth models are more similar to actual human teeth, while tooth-like material film models are easier to mass-produce.

[0077] The tooth model may include at least one of a full-mouth animal enamel model and a full-mouth tooth model made of tooth-like materials, and can test the wear condition of the full-mouth teeth.

[0078] In this application, the overall alternating evolution law of the actual oral environment is taken into account, which not only simulates the wear part, but also takes into account the acid erosion and the remineralization and repair of saliva, which is highly consistent with what actually happens in the oral cavity. Under this condition, the evaluation is sufficiently objective and fair.

[0079] According to this application, it can be helpful to standardize the oral industry and clearly define the safe use limits of oral care (toothbrush, toothpaste, water flosser) products or medical products (sandblasting); doctors can only give suggestions on the correct brushing method and speed, such as not brushing too fast or too hard, but cannot give standard values. This model can be used to verify whether the brushing method is correct, which will help us to standardize and accurately design product functions in the next step.

[0080] According to this application, it is helpful to evaluate the tooth wear effect of different oral products or different ways of using oral products, which can be used to guide product research and development and measure the actual effect of products.

[0081] The evaluation of this application is comprehensive enough. Wear may occur in different parts of the teeth, such as the tooth surface and the tooth neck. The dental conditions of different people (those with caries, acid reflux, and severe bacterial erosion) are different. By performing wear tests (as well as acid etching treatment and / or remineralization repair tests) on different parts of the tooth wear assessment model, it can be used to describe the wear conditions of specific populations.

[0082] The present invention is further described in detail below by means of specific examples. The following examples are only provided to further illustrate the present invention and should not be construed as limiting the present invention. In the present examples, unless otherwise specified, the reagents and instruments used are all commercially available, and the experimental procedures are all carried out in accordance with the product specifications and conventional experimental specifications.

[0083] Example 1: Preparation of tooth wear assessment model

[0084] Preparation of Human Enamel Models: Freshly extracted human premolars or third molars were collected, disinfected, and thoroughly cleaned. The roots were fixed and embedded in a wax block (2 cm × 2 cm × 2 cm), exposing the crown above the cementoenamel junction. The tooth was then mounted on a cutting machine stage. Under cooling liquid, the crown was removed at the cementoenamel junction, separating the crown and root, while retaining the crown. The buccal and lingual surfaces of the crown were polished with #2000 grit sandpaper under running water to create a smooth enamel surface. The tooth was then embedded in epoxy resin and removed after complete curing. The exposed enamel surface was polished sequentially with #3000 and then #5000 grit sandpaper under cooling water. The enamel surface was observed under an optical microscope to ensure uniform scratch direction. Finally, a cerium oxide polishing solution was prepared at a concentration of 80 g / L. The enamel surface was polished on a red gold velvet cloth while the solution was cooled until no scratches were visible under a light microscope. Use #400 grit sandpaper under water cooling to smooth the epoxy resin base. During the polishing process, use a vernier caliper to test the specimen flatness, ensuring that the height deviation at all locations on the specimen is within 0.02 mm. After ultrasonic cleaning for 10 minutes, place the specimen in distilled water and store it at room temperature until further testing.

[0085] Preparation of human enamel acid erosion model: The prepared human enamel model was immersed in an acidic environment (lactic acid solution, pH = 2) for demineralization for 30 minutes to simulate the local microenvironment of eating acidic substances, acid reflux or bacterial acid production. After demineralization, the surface was rinsed with ultrapure water three times to remove the residual acidic solution, and the sample was placed in a vacuum drying oven to dry overnight.

[0086] Preparation of Human Dentin Models: Intact, non-caries human third molars were collected and extracted and stored in a 0.9% (w / v) NaCl solution containing 0.02% sodium azide at 4°C. All extracted teeth were used within one month. The occlusal third of each crown was removed using a slow-speed Isomet saw (Buehler Ltd, Lake Bluff, IL) to expose the mid-coronal dentin. The specimens were then polished with 600-grit silicon carbide paper and rinsed with water for 1 minute to create a flat, standardized dentin surface. The specimens were then embedded in epoxy resin and removed after complete curing. The exposed dentin surface was polished sequentially using #3000 and #5000 grit sandpaper under water cooling. The enamel surface was observed under an optical microscope to ensure uniform scratch direction. The specimens were then inspected to ensure that the height deviation of each location was within 0.02 mm. The specimens were ultrasonically cleaned for 10 minutes and stored in distilled water at room temperature until further experiments.

[0087] Preparation of human dentin acid erosion model: The prepared human dentin model was immersed in an acidic environment (lactic acid solution, pH = 2) for demineralization for 30 minutes to simulate the local microenvironment of eating acidic substances, acid regurgitation or bacterial acid production. After demineralization, the surface was rinsed with ultrapure water three times to remove the residual acidic solution, and the sample was placed in a vacuum drying oven to dry overnight.

[0088] Preparation of the Bovine Enamel Model: Bovine teeth were obtained from animals euthanized at industrial slaughterhouses. After removing the roots, the collected anterior calf teeth were sterilized in a 10% formalin solution for 7 days. The teeth were then rinsed with ultrapure water and stored in a refrigerated (4°C) phosphate-buffered saline solution to minimize desalination, supplemented with thymol crystals to prevent bacterial growth. Only teeth that were free of enamel caries, hypoplasia, cracks, or other defects during the isolation process were selected for testing. The teeth were kept for a period of 3 months. Each tooth was cut into cubic specimens (approximately 7 mm × 7 mm × 2 mm), and the enamel surface was flattened and polished using wet silicon carbide abrasive paper with grits of 400, 800, 1500, 2000, 4000, and 5000. A water-cooled saw was then used to cut the specimens into flat enamel surfaces. Prior to sample processing, the sections were washed in running deionized water for 10 minutes and dried with compressed air for 5 seconds. The enamel sections were then embedded in epoxy resin, measuring approximately 10 mm × 10 mm × 7 mm. After solidification, the samples were polished using 800-grit sandpaper in a grinding and polishing unit to reveal completely flat enamel areas. The samples were then placed in specially machined stainless steel molds of the same size as the specimens, and the surface profile of the teeth was measured using a three-dimensional surface topography instrument. Only samples with a completely flat average surface profile were accepted.

[0089] Preparation of bovine enamel acid etching model: The prepared bovine enamel model was immersed in an acidic environment (lactic acid solution, pH = 2) for demineralization for 30 minutes to simulate the local microenvironment of eating acidic substances, acid reflux or bacterial acid production. After demineralization, the surface was rinsed with ultrapure water three times to remove the residual acidic solution, and the sample was placed in a vacuum drying oven to dry overnight.

[0090] Preparation of the Bovine Dentin Model: Bovine teeth were obtained from animals euthanized at an industrial slaughterhouse. All teeth were cleaned to remove any blood and stored in distilled water that was changed daily to prevent deterioration. The teeth were sectioned and the dentin isolated. Each tooth was cut into cubic specimens (approximately 7 mm × 7 mm × 2 mm), and the dentin surface was flattened and polished using wet silicon carbide abrasive paper with grits of 400, 800, 1500, 2000, 4000, and 5000. A water-cooled saw was then used to cut a flat dentin surface onto the specimen surface. Prior to sample processing, the sections were washed in running deionized water for 10 minutes and dried with compressed air for 5 seconds. The dentin sections were then embedded in epoxy resin with an overall size of approximately 10 mm × 10 mm × 7 mm. After solidification, the specimens were polished using 800-grit sandpaper in a grinding and polishing unit to reveal a completely flat dentin area. The sample is then placed in a specially machined stainless steel mold of the same size as the specimen, and the tooth's surface profile is measured using a 3D surface topography instrument. Only samples with a completely flat average surface profile are accepted.

[0091] Preparation of bovine dentin acid etching model: The prepared bovine dentin model was immersed in an acidic environment (lactic acid solution, pH = 2) for demineralization for 30 minutes to simulate the local microenvironment of eating acidic substances, acid regurgitation or bacterial acid production. After demineralization, the surface was rinsed with ultrapure water three times to remove the residual acidic solution, and the sample was placed in a vacuum drying oven to dry overnight.

[0092] Preparation of tooth-like material dental models: Hydroxyapatite powder is added to the grooves of a tooth mold, filling them as completely as possible without leaving any gaps. The powder-filled mold is then pressed together using a powder press and carefully demolded. A batch of demolded, pressed hydroxyapatite tablets are neatly arranged and placed in a high-temperature sintering furnace for 1100°C to convert the material into a ceramic. After cooling, the models are removed from the furnace and their dimensions are measured, selecting those with a diameter of 12 mm and a thickness of 2 mm. The surface profile of the hydroxyapatite tablets is measured using a 3D surface topography instrument. Only dense tablets with a completely flat average surface profile are accepted. The samples are ultrasonically cleaned with deionized water and dried for subsequent testing.

[0093] Preparation of tooth-like material tooth slice acid etching model: The prepared tooth-like material tooth slice model was immersed in an acidic environment (lactic acid solution, pH = 2) for demineralization for 30 minutes to simulate the local microenvironment of eating acidic substances, acid reflux or bacterial acid production. After demineralization, the surface was rinsed with ultrapure water 3 times to remove the residual acidic solution, and the sample was placed in a vacuum drying oven to dry overnight.

[0094] Preparation of a full-mouth enamel model: Human incisors, canines, and molars were collected, leaving the root and crown areas intact before cutting. Healthy teeth without cracks or caries were selected and disinfected and thoroughly cleaned. The exposed enamel surface was polished using #3000, #5000, and #400 grit sandpaper, sequentially, under water cooling. The enamel surface was observed under an optical microscope to ensure uniform scratch orientation. Finally, a cerium oxide polishing solution at a concentration of 80 g / L was prepared. The enamel surface was polished on a red velvet cloth under cooling conditions until no scratches were visible under an optical microscope. Finally, the enamel surface was smoothed using #400 grit sandpaper under water cooling. During polishing, the specimen was tested for flatness using a vernier caliper at five randomly selected 0.1 x 0.1 mm areas. The height deviation within each 0.1 x 0.1 mm area was ensured to be within 0.005 mm. After ultrasonic cleaning for 10 minutes, the samples were placed in distilled water and stored at room temperature until further testing. The collected teeth were then mounted on a denture (prepared using a 3D printer, using a resin with a viscosity of 500 mPa·s (25°C), an elongation at break of 362%, and a tensile strength of 3.2 MPa) according to their placement, simulating a real tooth model.

[0095] Preparation of full-mouth enamel acid-etched model: The prepared full-mouth enamel model was immersed in an acidic environment (lactic acid solution, pH = 2) for demineralization for 30 minutes to simulate the local microenvironment of eating, consuming acidic substances, acid reflux or bacterial acid production. After demineralization, the surface was rinsed with ultrapure water three times to remove the residual acidic solution, and the sample was placed in a vacuum drying oven to dry overnight.

[0096] Preparation of a full-mouth tooth model using tooth-like materials: Custom tooth molds were created based on the upper and lower half-mouth models. Hydroxyapatite powder was weighed and added to the mold troughs, filling them as completely as possible without leaving any gaps. The powdered molds were then pressed together using a powder tablet press. After reaching a certain pressure, the molds were released and carefully demolded. A batch of hydroxyapatite tablets, after demolding, were neatly arranged and placed in a high-temperature sintering furnace for 1100°C to convert the material into a ceramic. After cooling, the molds were removed from the furnace, ultrasonically cleaned with deionized water, and dried. The hydroxyapatite surfaces were then polished using #3000, #5000, and #400 grit sandpaper in sequence under water cooling. The enamel surface was observed under an optical microscope to ensure uniform scratch direction. Finally, a cerium oxide polishing solution was prepared at a concentration of 80 g / L. The hydroxyapatite surface was polished on a red gold velvet cloth while the solution cooled until no scratches were visible under an optical microscope. Finally, #400 grit sandpaper was used to polish the surface of the hydroxyapatite under water cooling conditions to make it flat. During the polishing process, a vernier caliper was used to randomly select 5 0.1*0.1mm areas on the surface of the sample to test the flatness of the specimen, and finally ensured that the height deviation of the specimen at each position within the 0.1*0.1mm area was within 0.005mm. After ultrasonic cleaning for 10 minutes, the sample was placed in distilled water and stored at room temperature for subsequent experiments. The teeth made of hydroxyapatite material were inlaid on the artificial gum material (prepared by 3D printer, the material was resin, with a viscosity of 500mPa·s (25℃), elongation at break of 362%, and tensile strength of 3.2MPa) to simulate the real tooth model.

[0097] Preparation of a full-mouth tooth acid-etched model made of tooth-like materials: The prepared full-mouth tooth model made of tooth-like materials was immersed in an acidic environment (lactic acid solution, pH = 2) for demineralization for 30 minutes to simulate the local microenvironment of eating, consuming acidic substances, acid reflux or bacterial acid production. After demineralization, the surface was rinsed with ultrapure water three times to remove the residual acidic solution, and the sample was placed in a vacuum drying oven to dry overnight.

[0098] Example 2: Wear testing of tooth wear assessment model

[0099] Three tooth wear assessment models (to avoid accidental errors, three parallel samples are usually set) are fixed in a straight line inside the groove of the 3D print, and samples prepared in the same batch are retained for comparison before and after brushing; according to the test group, each group of test sample electric toothbrushes are fixed on the manual brushing simulation device to ensure that the toothbrush does not move in the horizontal and vertical directions when it is turned on and off, and the brush head is always placed in the middle position of the tooth wear assessment model during the linear motion. When the toothbrush is not turned on, the contact surface between the tooth wear assessment model and the electric toothbrush is adjusted to stabilize the pressure. After confirming the brushing pressure (300g), brushing speed (28-30mm / s) and brushing time (30h), the device is turned on for brushing in accelerated aging mode. After brushing, the entire surface of the tooth wear assessment model is gently wiped with anhydrous ethanol to prevent debris falling during brushing from interfering with the subsequent characterization process.

[0100] The wear and tear of the enamel surface in both the worn and unworn areas of the wear specimens were quantitatively tracked using white light interferometry, scanning electron microscopy, and microhardness analysis. Wear curves were then drawn to identify characteristic wear stages, such as the running-in period and the stable wear period. The wear rate was also calculated, and a trend curve was obtained.

[0101] Measurement of the three-dimensional surface morphology of human enamel block specimens before and after wear: A white light interferometer (Up series, Rtecinstruments Inc., USA) was used to scan the trajectory before and after wear, and the wear volume loss was measured using corresponding software. Qualitative and quantitative characterization results such as three-dimensional morphology, surface defect height, defect size distribution, and surface roughness were obtained.

[0102] Measurement of surface morphology of human enamel block specimens before and after wear: After wear testing, the trajectory changes of each specimen before and after wear were initially observed using a stereomicroscope. Representative specimens from each group were affixed to conductive adhesive, sputter-coated with gold, and observed using a scanning electron microscope (SEM, Inspect F50, FEI, Hillsboro, OR, USA) at a relatively low speed under high vacuum at 20 kV.

[0103] Nanohardness measurements of human enamel block specimens before and after wear: Nanoindentation measurements were performed using a nanoindenter (Anton Paar Italia srl ​​Rivoli 10098 Italy) with a UNHT head equipped with a diamond Berkovich tip. The maximum load was 5 mN, the up-download rate was 10 mN / min, and the dwell time at the maximum load was 10 s. At least five measurements were performed for each sample, and the results are expressed as the mean ± SD.

[0104] Statistical analysis was performed using commercially available software (SPSS 18.0, IBM, Armonk, NY, USA). One-way analysis of variance and Dunnett's T3 test were performed to compare the wear volume loss of the tooth wear assessment model between different groups. The t-test was performed to evaluate the variability of different samples tested on the same specimen. A p-value of less than 0.05 was considered statistically significant.

[0105] Example 3: Remineralization Test of Tooth Wear Assessment Model

[0106] The tooth wear assessment model that had undergone wear testing was immersed in artificial saliva (1.45mmol / L calcium hydrogen phosphate, pH 6.8) at a constant temperature of 37°C to simulate the physiological remineralization process in the mouth. Samples were taken at different time points for tissue structure analysis to obtain the dynamic process of remineralization repair after the sample was damaged. The growth of remineralized crystals in the enamel surface damage was quantitatively analyzed, and the cumulative trend of surface deposited crystals with mineralization time was explored. The changes in the enamel surface morphology and roughness during the mineralization process were observed, the physical and chemical properties of the deposited crystals were characterized, and comprehensive information on the remineralization repair of the sample surface damage was obtained. The worn area was scanned again using a three-dimensional surface topography instrument and atomic force microscope. A constant reference point was selected to measure the amount of enamel surface crystals gained and the surface roughness in the target area. The data from each observation point were combined to form a curve of the change in repair amount, which was used to evaluate the repair ability of saliva for enamel damage. Scanning electron microscopy was used to observe the enamel surface repair morphology; XRD was used to analyze the type, size and other parameters of the deposited crystals; EDX was used to analyze the composition of the crystal elements; a scratch test was used to examine the degree of bonding of the deposited crystals; and a nanoindenter was used to obtain the hardness and modulus of the enamel repair layer.

[0107] Safety performance assessment: When the enamel wear rate or damage amount caused by external mechanical factors is lower than the remineralization rate or the growth amount of remineralized crystals under normal oral conditions, it is considered that this external action mode will not cause adverse effects on personal oral health problems; when the enamel wear rate or damage amount caused by external mechanical factors is higher than the remineralization rate or the growth amount of remineralized crystals under normal oral conditions, it is considered that this external action mode will cause irreversible damage to personal oral health and a warning should be given.

[0108] Example 4: Evaluating Oral Products Using Tooth-like Material Dental Film Models

[0109] This embodiment uses a tooth-like material tooth slice model (i.e., hydroxyapatite slice) to evaluate the oral hard tissue safety of electric toothbrush motor parameters (vibration intensity). The hydroxyapatite slice is used as a research tool to perform aging-accelerated brushing treatment on the sample surface (simulating the brushing process of human hands on the enamel surface). During the test, the brushing time, brushing force, brushing direction, and brushing speed are fixed. The surface of the sample before and after brushing is qualitatively and quantitatively analyzed to detect the degree of damage to the hydroxyapatite surface caused by the sample to be tested. Afterwards, the brushed sample is immersed in artificial saliva for remineralization treatment (simulating the remineralization process of enamel in the human oral environment). The remineralization process after brushing the sample is qualitatively and quantitatively analyzed to detect the degree of repair of the hydroxyapatite slice surface by artificial saliva. Finally, according to the wear condition, a hydroxyapatite slice model oral hard tissue safety assessment system is established. The details are as follows:

[0110] Three hydroxyapatite sheets (HAP), also known as tooth-like material tooth sheet models (to avoid accidental errors, three parallel samples are usually set up) are fixed in a straight line inside the groove of the 3D printed part. A fixed cover is used to cover half of the hydroxyapatite sheet and not perform the subsequent brushing process, which is used as a sample control before and after brushing; the other half that is not covered is used as the brushing area for brushing treatment; according to the test group, each group of test sample electric toothbrushes are fixed on the human hand brushing simulation device to ensure that the toothbrush is not turned on and on. In this state, there is no displacement in the horizontal and vertical directions, and the brush head is always placed in the middle of the hydroxyapatite sheet during linear motion. When the toothbrush is not turned on, adjust the contact surface between the hydroxyapatite sheet and the electric toothbrush to stabilize the pressure. After confirming the brushing pressure (350g), brushing speed (28-30mm / s) and brushing time (30h), turn on the device and perform brushing in accelerated aging mode. After brushing, use anhydrous ethanol to gently wipe the entire surface of the hydroxyapatite sheet to prevent debris dropped during brushing from interfering with the subsequent characterization process. The following table shows the parameters of different test groups:

[0111] Test brush sample number Vibration frequency (Hz) Speed ​​(r / min) No. 1 250 30000 No. 5 208.33 25000 No. 10 291.67 35000 No. 15 333.34 40000 No. 20 450 54000

[0112] The hydroxyapatite sheets before and after wear were photographed using a stereo microscope. Figure 1 This is a stereo microscope surface photograph of the tooth model before and after abrasion using sample No. 1 involved in Example 4 of the present application. Figure 2 This is a stereomicroscope surface photograph of the tooth model before and after abrasion using sample No. 5 involved in Example 4 of the present application. Figure 3 This is a stereo microscope photograph of the tooth model before and after abrasion using sample No. 10 involved in Example 4 of the present application. Figure 4This is a stereomicroscope surface photograph of the tooth model before and after abrasion using sample No. 15 involved in Example 4 of the present application. Figure 5 This is a stereo microscope surface photograph of the tooth model before and after the wear of the sample No. 20 involved in Example 4 of this application. Figures 1 to 5 As shown, after brushing samples No. 1, 5 and 10, a small amount of friction marks can be observed under the microscope, but the signs of friction are not particularly obvious; after brushing samples No. 15 and 20, obvious wear marks can be observed under the microscope, and after brushing sample No. 20, the wear marks are the most obvious.

[0113] Scanning electron microscopy (SEM, Inspect F50, FEI, Hillsboro, OR, USA) was used to observe and photograph the wear of the hydroxyapatite sheet before and after wear at a relatively low speed under high vacuum at 20 kV. Figure 6 This is a scanning electron microscope image of the tooth model before and after abrasion using sample No. 1 involved in Example 4 of the present application. Figure 7 This is a scanning electron microscope image of the tooth model before and after being worn using sample No. 5 involved in Example 4 of the present application. Figure 8 This is a scanning electron microscope image of the tooth model before and after abrasion using sample No. 10 involved in Example 4 of the present application. Figure 9 This is a scanning electron microscope image of the tooth model before and after abrasion using sample No. 15 involved in Example 4 of the present application. Figure 10 This is a scanning electron microscope image of the tooth model before and after the wear of the sample No. 20 involved in Example 4 of the present application. Figures 6 to 10 As shown in the figure, after brushing, samples No. 1, 5 and 10 were observed under an electron microscope. It can be seen that the process of brushing wear polishes the originally uneven material surface into a relatively smooth surface, and no obvious signs of brushing wear appear. After brushing, samples No. 15 and 20 have a large range of vertical stripes on the surface, which are consistent with the direction of the brushing movement. These are probably irreversible signs caused by brushing wear, which is consistent with the phenomenon observed under a stereo microscope.

[0114] A white-light interferometer (Up series, Rtec Instruments Inc., USA) was used to scan the hydroxyapatite disc before and after wear. Three-dimensional topography, surface defect height, defect size distribution, and surface roughness were analyzed. Statistical analysis was performed using commercially available software (SPSS 18.0, IBM, Armonk, NY, USA). One-way analysis of variance and Dunnett's T3 test were performed to compare wear volume loss between groups. Student's t-test was performed to assess variability between different samples tested on the same specimen. A p-value of less than 0.05 was considered statistically significant. Figure 11This is an analysis diagram of the three-dimensional morphology, surface defect height, defect size distribution, and surface roughness of the tooth model before and after wear using sample No. 1 involved in Example 4 of the present application. Figure 12 This is an analysis diagram of the three-dimensional morphology, surface defect height, defect size distribution, and surface roughness of the tooth model before and after wear using sample No. 5 involved in Example 4 of the present application. Figure 13 This is an analysis diagram of the three-dimensional morphology, surface defect height, defect size distribution, and surface roughness of the tooth model before and after wear using sample No. 10 involved in Example 4 of the present application. Figure 14 This is an analysis diagram of the three-dimensional morphology, surface defect height, defect size distribution, and surface roughness of the tooth model before and after wear using sample No. 15 involved in Example 4 of the present application. Figure 15 This is an analysis diagram of the three-dimensional morphology, surface defect height, defect size distribution and surface roughness of the tooth model before and after wear using sample No. 20 involved in Example 4 of this application. Figures 11 to 15As shown, the surface defect height difference of sample No. 1 before and after brushing is less than 10μm, and the defect size is concentrated around 4-8μm. The surface roughness before and after brushing is similar. Overall, the surface damage caused by wear of sample No. 1 before and after brushing is not obvious. The surface defect height difference of sample No. 5 before and after brushing is less than 10μm, and the defect size is concentrated around 4μm. The surface roughness before and after brushing is similar. Overall, the surface damage caused by wear of sample No. 5 before and after brushing is not obvious. The surface defect height difference of sample No. 10 before brushing is less than 10μm, and the surface defect height difference after brushing is greater than 10μm. The defect size before brushing is concentrated around 4μm, and the defect size after brushing is concentrated around 7.6μm. The surface roughness before and after brushing is similar. Overall, the wear scar depth caused by wear of sample No. 10 after brushing is shallow. The distribution of overall surface defects tends to deepen with the wear, but the surface roughness does not change significantly. The surface defect height of sample No. 15 before brushing is less than 10μm, and the surface defect height after brushing is about 15 to 20μm. The defect size before brushing is concentrated around 8μm, and the defect size after brushing is concentrated around 12.8μm. The surface roughness before and after brushing is similar. Overall, after brushing, the wear of sample No. 15 causes a wear scar with a depth of about 5 to 10μm. The distribution of the overall surface defects also deepens with wear, but the surface roughness does not change significantly. The surface defect height of sample No. 20 before brushing is less than 10μm, and the surface defect height after brushing is about 20μm. The defect size before brushing is concentrated around 8μm, and the defect size after brushing is concentrated around 14.4μm. The surface roughness is significantly improved after brushing. Overall, after brushing, the wear height of sample No. 20 increases due to wear, forming a wear scar of about 10μm. The distribution of the overall surface defects also deepens with wear, and the surface roughness is significantly improved. In summary, analysis of the 3D topography and quantitative test results indicates that brushes No. 1 and No. 5 exert negligible friction on the hydroxyapatite surface before and after brushing, with a slight decrease in roughness after brushing, demonstrating that the friction process primarily smoothes the previously uneven surface. Brush No. 10 exhibits an increase in surface defect distribution from 4 microns to 7.6 microns, causing slight wear, but overall surface roughness decreases. This suggests that the friction process still involves smoothing the previously uneven surface, representing the critical point of wear. Brushes No. 15 and No. 20 produce wear marks larger than 5 microns on the aligned surface after brushing, and these marks deepen with increasing vibration frequency or rotational speed. Therefore, the wear process of brushes with different vibration intensities can be divided into a polishing phase and a damage phase, each with distinct wear characteristics. When brushing with moderate force, correct technique, and moderate frequency, the wear process manifests as a polished, flattened surface.Improper brushing technique, excessive force, or excessive motor vibration intensity are the main causes of early enamel loss, leading to higher wear rates and significant enamel loss. HAP wear increases with increasing speed or frequency. When speeds exceed 40,000 r / min or frequencies exceed 330 Hz, prolonged brushing can cause significant damage to the HAP surface. These results are consistent with surface photographs observed under a stereomicroscope and surface topography images obtained under an electron microscope.

[0115] The hydroxyapatite sheets, which had undergone wear testing, were placed in artificial saliva (1.45 mmol / L calcium hydrogen phosphate, pH 6.8) at a constant temperature of 37°C to simulate the physiological remineralization process in the mouth. After seven days of in vitro remineralization in the artificial saliva medium, three-dimensional morphology and quantitative characterization revealed that the surface defect height and defect size distribution in the worn area were repaired to a value of 1 micron.

[0116] Based on the wear test and remineralization test results of samples No. 1, 5, 10, 15 and 20 on hydroxyapatite sheets, a hydroxyapatite sheet electric toothbrush vibration frequency safety assessment system was established as shown in the following table:

[0117]

[0118] As shown in the table above, based on scientific quantitative indicators, the safety level is divided into four levels: severe injury, injury, injury risk warning, and safety. Among them, the safety level corresponding to sample No. 20 is severe injury, the safety level corresponding to sample No. 15 is injury, the safety level corresponding to sample No. 10 is injury risk warning, and the safety level corresponding to samples No. 1 and No. 5 is safe.

[0119] This embodiment establishes a process and a safety assessment system for testing the safety of electric toothbrushes with different vibration frequencies or rotational speeds. According to this embodiment, the safety of electric toothbrushes with different vibration frequencies or rotational speeds can be scientifically and effectively assessed.

[0120] Example 5: Evaluation of oral products using a human enamel acid erosion model

[0121] This embodiment uses a human enamel acid-etched model to evaluate the safety of electric toothbrush motor parameters (vibration intensity) in oral hard tissues. The human enamel model after acid etching is used as a research tool, and the surface of the sample is subjected to accelerated aging brushing treatment (simulating the brushing process of human hands on the enamel surface). During the test, a certain brushing time, brushing force, brushing direction and brushing speed are fixed. By qualitatively and quantitatively analyzing the surface of the sample before and after brushing, the degree of damage to the enamel surface after acid etching by the sample to be tested is detected; then, the brushed sample is immersed in artificial saliva for remineralization treatment (simulating the remineralization process of enamel in the human oral environment), and the degree of repair of the enamel surface by artificial saliva is detected by qualitatively and quantitatively analyzing the remineralization process after brushing the sample. Finally, according to the wear condition, a human enamel acid-etched model oral hard tissue safety assessment system is established. The details are as follows:

[0122] Three acid-etched human enamel models, also known as human enamel acid-etched models (to avoid accidental errors, three parallel samples are usually set up) are fixed in a straight line inside the groove of the 3D print, and samples prepared in the same batch are retained for comparison before and after brushing; according to the test group, each group of test sample electric toothbrushes are fixed on a human hand brushing simulation device to ensure that the toothbrush does not move in the horizontal and vertical directions when it is not turned on and when it is turned on, and the brush head is always placed in the middle of the human enamel block during the linear motion. When the toothbrush is not turned on, the contact surface between the human enamel model and the electric toothbrush is adjusted to stabilize the pressure. After confirming the brushing pressure (300g), brushing speed (28-30mm / s) and brushing time (30h), the device is turned on for brushing in accelerated aging mode. After brushing, the entire surface of the human enamel model is gently wiped with anhydrous ethanol to prevent debris falling during the brushing process from interfering with the subsequent characterization process. The following table shows the parameters of different test groups:

[0123] Test brush sample number Vibration frequency (Hz) Speed ​​(r / min) No. 1 250 30000 No. 10 291.67 35000 No. 15 333.34 40000 No. 20 450 54000

[0124] The wear of the human enamel model before and after acid etching was characterized, as well as the wear of the human enamel acid-etched model before and after abrasion using different electric toothbrush samples. The specific operating steps were the same as those in Example 4. The characterization results are shown in the following table:

[0125]

[0126] The human enamel model that had undergone wear was placed in artificial saliva at a constant temperature of 37°C to simulate the physiological remineralization process in the mouth. Samples were taken at different time points for tissue structure analysis to obtain the dynamic process of remineralization and repair of the damaged human enamel model. After 7 days of in vitro remineralization treatment in artificial saliva medium, a layer of mineralized crystals with similar composition to the original human enamel but different growth direction was generated on the enamel surface. This layer of crystals had no obvious growth orientation along the C axis. The results of three-dimensional morphological quantitative characterization showed that the surface roughness repair amount of the worn area was 1 micron, and the surface defect height and defect size distribution repair amount was 3 to 5 microns.

[0127] Based on the wear test and remineralization test results of samples No. 1, 10, 15, and 20 on the human enamel acid erosion model, a safety assessment system for electric toothbrush vibration frequency using the human enamel acid erosion model was established as shown in the following table:

[0128]

[0129] By qualitatively and quantitatively analyzing the wear of the surface of the human enamel acid-etched model under the condition of microscopic three-dimensional surface morphology characterization, it can be seen that number 1 corresponds to the low-frequency mode (speed below 35,000 r / min), which does not cause any damage to the teeth; numbers 15 and 20 correspond to high-frequency modes (speed above 40,000 r / min), which can cause damage to the teeth. The degree of damage caused under these conditions far exceeds the mineralization rate of saliva on the teeth, which may lead to an increased risk of oral diseases; number 10 corresponds to a speed between 35,000 and 40,000 r / min, which is the safety boundary. If the brushing method is incorrect, the force is too strong, or the horizontal brushing is too fast, it is very easy to cause irreversible damage to the teeth. Based on this data, the tolerance and response of the enamel surface to the vibration and friction of the electric toothbrush can be clarified, thereby determining the parameter design and usage limits of the electric toothbrush, avoiding enamel wear, tooth decay, or other oral problems caused by high-speed brushing.

[0130] The above content is a further detailed description of the present application in conjunction with specific implementation methods, and the specific implementation of the present application cannot be considered to be limited to these descriptions. For ordinary technicians in the technical field to which the present application belongs, several simple deductions or substitutions can be made without departing from the concept of the present application.

Claims

1. A tooth wear assessment model for evaluating the safety of oral products, characterized in that: The tooth wear assessment model is obtained by at least grinding and polishing the surface of a tooth model, wherein the tooth model includes at least one of an animal enamel block model, an animal dentin block model, a tooth film model of a tooth-like material, a full-mouth animal enamel model, and a full-mouth tooth model of a tooth-like material.

2. The tooth wear assessment model according to claim 1, characterized in that The tooth model includes at least one of an animal enamel block model, an animal dentin block model, and a tooth film model made of a tooth-like material.

3. The tooth wear assessment model according to claim 1, wherein: The height deviation of each position on the surface of the tooth wear assessment model is less than or equal to 0.02 mm.

4. The tooth wear assessment model according to claim 1, wherein: The oral products include oral care products and oral appliances, wherein the oral care products include at least one of toothpaste, mouthwash, tooth powder, toothbrush, electric toothbrush, oral irrigator and dental floss, and the oral appliances include sandblasting.

5. The tooth wear assessment model according to any one of claims 1 to 4, characterized in that: The tooth wear assessment model is also obtained by performing an acid etching treatment on the tooth model, wherein the acid etching treatment includes: contacting the tooth model with an acid solution for a predetermined time.

6. The tooth wear assessment model according to claim 5, characterized in that: The pH value of the acidic solution is 1 to 6.

7. A method for preparing a tooth wear assessment model according to any one of claims 1 to 6, characterized in that: include: The surface of the tooth model is ground and polished to obtain the tooth wear assessment model.

8. The preparation method according to claim 7, characterized in that The grinding and polishing include: wet grinding with #400 to #5000 grit sandpaper and / or 400 to 5000 grit silicon carbide paper; or polishing with a polishing liquid with a cerium oxide concentration of 80 g / L.

9. Use of the tooth wear assessment model according to any one of claims 1 to 6 in evaluating the safety of oral products.

10. The use according to claim 9, characterized in that The method comprises performing a wear test using the tooth wear assessment model; the wear test comprises: subjecting the oral product to a contact friction treatment on the tooth wear assessment model, and recording the wear condition of the surface of the tooth wear assessment model before and after the contact friction treatment.

11. The use according to claim 10, characterized in that The oral product is a toothbrush or an electric toothbrush, and the wear test includes: fixing the tooth wear evaluation model on a test bench, and using a three-dimensionally movable robotic arm to control the oral product to perform contact friction processing on the tooth wear evaluation model.

12. The use according to claim 11, characterized in that The robotic arm control system stores or inputs different brushing parameters, and the robotic arm control system controls the robotic arm to clamp the oral product and causes the oral product to perform contact friction processing on the tooth wear assessment model according to the preset brushing parameters; wherein the brushing parameters include at least one of the moving path, brushing angle, brushing force, brushing speed and brushing time.

13. The use according to claim 12, characterized in that The selection range of the brushing angle is 0° to 90°, the selection range of the brushing force is 0g to 100g, and the selection range of the brushing speed is 0mm / s to 50mm / s.

14. The use according to claim 10, characterized in that When the tooth wear assessment model is subjected to contact friction treatment using the oral product, the tooth wear assessment model is immersed in a liquid medium, and the liquid medium is circulated.

15. The use according to any one of claims 9 to 14, characterized in that: The wear condition of the surface of the tooth wear assessment model includes at least one of the wear volume loss, surface defect height, surface roughness and nano-microhardness of the surface of the tooth wear assessment model. The safety of the oral product is evaluated based on the wear condition of the surface of the tooth wear assessment model.

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