Preparation method of model tooth composite ceramic material for teaching

Abstract

The invention relates to the technical field of model tooth materials, and particularly discloses a preparation method of a model tooth composite ceramic material for teaching, and the preparation method comprises the following steps: mixing pentaerythritol tetrakis (3-mercaptopropionate) and triallyl isocyanurate, and stirring in a water bath to obtain a mixture; adding zinc polyacrylate into a propylene glycol methyl ether acetate solvent, uniformly dispersing, mixing with the mixture, adding benzoin dimethyl ether, stirring, continuously adding the solvent until the solid content is 40%, stirring in a water bath for reaction, and carrying out vacuum defoaming to form matrix slurry; adding nano-hydroxyapatite and a photoinitiator into the matrix slurry subjected to vacuum defoaming to prepare inner-layer slurry, and adding nano-silica, the photoinitiator and a fluorescent whitening agent to prepare outer-layer slurry; solidifying the slurry layer by layer to construct a model; and curing at low temperature. The model tooth can be used for classroom teaching, and has the advantages of high hardness and good durability.

Description

Technical Field

[0001] This application relates to the field of dental model materials technology, and more specifically, it relates to a method for preparing a composite ceramic material for teaching dental models. Background Technology

[0002] In the practice of medical education and clinical oral teaching, model teeth, as a key teaching tool that simulates the structure and operating environment of real teeth, play a crucial role in many teaching aspects such as tooth morphology recognition, restoration fabrication, tooth preparation, and root canal treatment.

[0003] However, current teaching model teeth face many problems in practical applications that urgently need to be solved, which seriously restrict the improvement of teaching quality and the optimization of teaching costs.

[0004] From a materials performance perspective, the materials used in traditional teaching model teeth have significant defects. Some materials lack wear resistance and are prone to wear or debris during frequent drilling and cutting operations. This not only shortens the lifespan of the model teeth and increases teaching costs, but also affects students' accurate understanding of tooth structure due to changes in surface morphology. Other materials are brittle and lack toughness, making them prone to fracture under external impact, posing a safety hazard of flying fragments. This limits the use of some high-intensity procedures in teaching and hinders students' comprehensive mastery of clinical skills.

[0005] In terms of long-term performance, traditional model teeth are prone to mechanical property degradation during repeated use. Due to material aging or decreased interfacial bonding, model teeth may experience interlaminar cracking and decreased strength after repeated thermal cycles or humid and hot environments, rendering them unable to meet the needs of long-term teaching. This not only increases the waste of teaching resources but may also affect the teaching progress and quality due to the unstable performance of the model teeth.

[0006] In terms of expanding teaching functions, traditional model teeth have limited functionality and lack intelligent responsiveness. For example, they do not have self-healing capabilities; if damage occurs during operation, they cannot repair themselves and must be discarded and replaced, increasing teaching costs.

[0007] Therefore, we need to develop a new type of composite ceramic material for teaching model teeth. Summary of the Invention

[0008] To improve the wear resistance and durability of model teeth, this application provides a method for preparing a composite ceramic material for teaching model teeth.

[0009] This application provides a method for preparing a composite ceramic material for teaching model teeth, using the following technical solution: A method for preparing a composite ceramic material for teaching model teeth includes the following steps: (1) Preparation of matrix slurry: Pentaerythritol tetrakis(3-mercaptopropionic acid) and triallyl isocyanurate are mixed and stirred in a water bath at 200-300 rpm for 20-30 min at 55-65℃ to obtain a mixture; Zinc polyacrylate is added to propylene glycol methyl ether acetate solvent and stirred to disperse evenly, and then mixed with the mixture. Benzoin dimethyl ether is added and stirred evenly. Propylene glycol methyl ether acetate solvent is added to a solid content of 40%. The mixture is stirred in a water bath at 200-300 rpm for 2-3 hours at 55-65℃. After vacuum degassing, the matrix slurry is formed. (2) Layered slurry preparation: Inner layer slurry: Take the matrix slurry after vacuum degassing treatment, add nano hydroxyapatite and photoinitiator in sequence, mix and stir evenly to obtain the inner layer slurry; Outer layer slurry: After vacuum degassing, nano-silica, photoinitiator and fluorescent whitening agent are added to the matrix slurry in sequence and stirred evenly to obtain the outer layer slurry; (3) The model is constructed by layering photopolymerization 3D printing technology and solidifying the slurry layer by layer. (4) Low temperature curing: Curing under ultraviolet light at 50-70℃ for 2-3 hours.

[0010] By employing the above technical solution, the thiol group (-SH) in pentaerythritol tetrakis(3-mercaptopropionic acid) ester and the carbon-carbon double bond (C=C) in triallyl isocyanurate undergo a thiol-alkene click reaction under the action of the photoinitiator benzoin dimethyl ether, thereby forming a dynamic covalent bond network of thiol-alkene. This dynamic covalent bond has unique reversibility; under heat treatment conditions of 60℃, when the material is damaged, the thiol-alkene bonds can break and recombine, rapidly repairing microcracks in the material and achieving self-healing. Simultaneously, the zinc ion coordination network also plays a role, Zn... 2+ They migrate to the damage site and re-coordinate with carboxyl / phosphate groups, enhancing the material's toughness recovery.

[0011] Optionally, the matrix slurry includes the following raw materials in parts by weight: 40-60 parts of pentaerythritol tetrakis(3-mercaptopropionic acid), 20-30 parts of triallyl isocyanurate, 0.2-0.5 parts of dimethyl benzoate, and 15-25 parts of zinc polyacrylate.

[0012] By adopting the above technical solution, the matrix slurry prepared by the reasonable proportion of raw materials through a specific process lays the foundation for the subsequent formation of a gradient structure and improvement of wear resistance, effectively solving the problems of easy damage and difficult maintenance of teaching models.

[0013] Optionally, the inner layer slurry includes the following raw materials in parts by weight: 90-110 parts of matrix slurry, 55-65 parts of nano hydroxyapatite, and 1-2 parts of photoinitiator; The outer layer slurry comprises the following raw materials in parts by weight: 90-110 parts of matrix slurry, 35-45 parts of nano-silica, 0.4-0.6 parts of photoinitiator, and 0.1-0.3 parts of fluorescent whitening agent.

[0014] By adopting the above technical solution, in the inner layer slurry, based on a specific weight proportion of the matrix slurry, nano-hydroxyapatite and a photoinitiator are added. The photoinitiator facilitates subsequent light curing, while the nano-hydroxyapatite interacts with the components in the matrix slurry and can exchange ions with Zn²⁺ in the matrix, enhancing the bond with the matrix and forming a dentin-like structure, thus giving the material good biocompatibility and mechanical properties. In the outer layer slurry, also based on the matrix slurry, nano-silica and a fluorescent whitening agent are added. Nano-silica increases the hardness of the outer layer, forming a hard surface similar to tooth enamel, while the fluorescent whitening agent makes the model tooth's appearance closer to the color of real teeth. This slurry formulation with different components in the inner and outer layers, after layered light curing, constructs a biomimetic tooth gradient structure, giving the model tooth both the flexibility of the inner layer and the hardness of the outer layer, improving overall wear resistance and strength, and providing a realistic appearance, better meeting teaching needs and solving the problems of poor performance and appearance of traditional teaching model teeth.

[0015] Optionally, the nano-hydroxyapatite undergoes a pretreatment operation before being added, specifically as follows: the nano-hydroxyapatite is ultrasonically treated in a 5 wt% γ-(methacryloyloxy)propyltrimethoxysilane ethanol solution for 30 min. The nano-silica undergoes a pretreatment process before being added, specifically as follows: nano-silica and isopropyltris(dioctylpyrophosphoryloxy)titanate are mixed at a mass ratio of 96-98:2 and ball-milled for 10-15 minutes.

[0016] By employing the above technical solution, nano-hydroxyapatite is ultrasonically treated with a 5wt% γ-(methacryloyloxy)propyltrimethoxysilane ethanol solution for 30 min. The siloxane groups at one end of the silane coupling agent undergo a hydrolytic condensation reaction with the hydroxyl groups on the surface of the nano-hydroxyapatite, forming chemical bonds. Meanwhile, the methacryloyloxy groups at the other end can undergo a cross-linking reaction with the photocurable resin system in the matrix slurry, enhancing the interfacial bonding between the nano-hydroxyapatite and the matrix, making the inner structure more stable, improving the mechanical properties of the material, and simultaneously promoting the reaction of Zn²⁺ with Ca in the nano-hydroxyapatite. Ion exchange of ²⁺ optimizes the performance of the inner layer; nano-silica and isopropyltris(dioctylpyrophosphoryloxy)titanate are mixed at a mass ratio of 96-98:2 and ball-milled for 10-15 minutes. The long-chain alkyl groups in the titanate coupling agent molecules physically adsorb onto the surface of nano-silica, and their polar groups can interact with the components in the matrix slurry, improving the dispersion of nano-silica in the matrix, reducing agglomeration, making the outer layer structure more uniform and dense, improving the hardness and wear resistance of the outer layer, and thus enhancing the performance of the entire model tooth composite ceramic material, making it more suitable for teaching needs.

[0017] Optionally, after low-temperature curing, a nano-silica sol-polyurethane composite coating is sprayed onto the surface, the coating comprising the following raw materials in parts by weight: 40-60 parts of nano-silica sol, 30-50 parts of polyurethane acrylate, and 1-5 parts of photoinitiator.

[0018] Optionally, the preparation of the nano-silica sol-polyurethane composite coating includes the following steps: The nano-silica sol is mixed with polyurethane acrylate, a photoinitiator is added, and the mixture is stirred at 500-800 rpm for 30-60 minutes in a water bath at 40-50℃ until fully mixed.

[0019] By employing the above technical solution, the nano-sized silica particles in the nano-silica sol have a large number of hydroxyl groups on their surface, and the polyurethane acrylate contains polymerizable carbon-carbon double bonds. Under the action of a photoinitiator, the polyurethane acrylate undergoes a photopolymerization reaction to form a polymer network structure. Simultaneously, the silica particles in the nano-silica sol are embedded into this network structure through physical adsorption and chemical bonding, forming a tightly bonded composite coating. The beneficial effects of this composite coating are that the addition of nano-silica sol improves the coating's hardness and wear resistance, enabling it to better resist external forces such as drilling and grinding; the polyurethane acrylate imparts good flexibility and adhesion to the coating, ensuring that the coating is tightly bonded to the model tooth matrix and is not easily detached; the synergistic effect of the two greatly improves the wear resistance of the model tooth, and the coating also has a certain antibacterial effect, while improving the appearance and feel of the model tooth, extending the service life of the teaching model, and reducing teaching costs.

[0020] Optionally, the composite coating is applied to the surface of the model tooth at a rate of 5 mg / cm². 2 .

[0021] By adopting the above technical solution, controlling the spraying amount ensures that the composite coating formed by nano-silica sol and polyurethane acrylate uniformly covers the surface of the model tooth. During drilling and grinding operations, the coating is neither too thick, leading to easy peeling, nor too thin, failing to effectively resist wear, thus effectively improving the wear resistance of the model tooth and greatly extending its service life. Regarding adhesion, this spraying amount allows for a good bonding interface between the coating and the model tooth substrate, fully utilizing the flexibility and adhesion properties of polyurethane acrylate, ensuring a tight fit and preventing detachment due to external forces. In terms of antibacterial properties, an appropriate coating amount evenly distributes antibacterial components, and with the synergistic effect of nano-silica and other components, achieves a high antibacterial rate, effectively inhibiting bacterial growth and ensuring hygiene and safety for teaching use. Simultaneously, a suitable spraying amount also ensures good appearance and feel of the model tooth, more closely resembling real teeth, meeting teaching needs, and reasonably controlling costs while ensuring performance, thus reducing teaching expenses.

[0022] Optionally, 0.5-1.5 parts of yttrium fluoride are also added to the outer slurry.

[0023] By adopting the above technical solution, the addition of yttrium fluoride can further improve the hardness and wear resistance of the outer layer material of the model tooth, making it closer to the characteristics of natural tooth enamel, thereby improving the overall performance of the model tooth.

[0024] In summary, this application has the following beneficial effects: 1. This application utilizes a layered slurry design with an inner layer of nano-hydroxyapatite and an outer layer of nano-silica, combined with photopolymerization 3D printing technology, to construct a biomimetic tooth gradient structure. The inner layer simulates the flexibility and biocompatibility of dentin, while the outer layer simulates the hardness and wear resistance of enamel, giving the model tooth both high strength and high toughness, significantly improving wear resistance and meeting teaching needs.

[0025] 2. This application utilizes the mercapto-olefin click reaction between pentaerythritol tetrakis(3-mercaptopropionic acid) and triallyl isocyanurate to form a dynamic covalent network, which, combined with a zinc ion coordination network, enables the material to achieve self-healing capabilities under 60°C heat treatment. The dynamic covalent bonds reversibly fracture and recombine to rapidly repair surface cracks, while zinc ions migrate to the damaged sites to enhance toughness recovery. After teaching, the material can be placed in an insulated chamber for maintenance to repair microcracks caused during use, thereby extending the lifespan of the model tooth and reducing teaching costs.

[0026] 3. This application significantly improves the wear resistance, antibacterial properties, and appearance and feel of model teeth by spraying a 5 mg / cm² nano-silica sol-polyurethane composite coating, combined with the rheological regulation effect of yttrium fluoride. In the composite coating, nano-silica enhances hardness, polyurethane acrylate provides flexibility and adhesion, and yttrium fluoride optimizes the gradient layer structure. The synergistic effect of these three components makes the model teeth more closely resemble real teeth, ensuring teaching hygiene and safety, while also reasonably controlling costs. Detailed Implementation

[0027] The following detailed description of this application is provided in conjunction with the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments are all from commercially available sources.

[0028] Polyurethane acrylate was purchased from Yinhuang (Shanghai) Industrial Co., Ltd., model EB8413; zinc polyacrylate, CAS No.: 25916-47-6; nano silica sol was purchased from Hangzhou Jiuli Biomaterials Co., Ltd., model JL-SO1, with a particle size of 10nm; polyurethane acrylate was purchased from Yinhuang (Shanghai) Industrial Co., Ltd., item number EB4491, model EBECREL 4491.

[0029] Preparation examples of raw materials and / or intermediates Example of preparation of nano-silica sol-polyurethane composite coating

[0030] Preparation Example 1 The preparation of the nano-silica sol-polyurethane composite coating includes the following steps: 50 kg of nano silica sol was added to 40 kg of polyurethane acrylate while stirring. After the addition was complete, the mixture was stirred at 500 rpm for 10 min. Then, 2 kg of 2-hydroxy-2-methyl-1-phenylpropanone (photoinitiator) was added and mixed thoroughly. The mixture was then stirred at 655 rpm for 40 min in a 40°C water bath until it was fully mixed.

[0031] Preparation Example 2 The preparation of the nano-silica sol-polyurethane composite coating includes the following steps: 40 kg of nano silica sol was added to 50 kg of polyurethane acrylate while stirring. After the addition was complete, the mixture was stirred at 500 rpm for 10 min. Then, 4 kg of 2-hydroxy-2-methyl-1-phenylpropanone (photoinitiator) was added and mixed thoroughly. The mixture was then stirred at 500 rpm for 60 min in a 45°C water bath until it was fully mixed.

[0032] Preparation Example 3 The preparation of the nano-silica sol-polyurethane composite coating includes the following steps: 60 kg of nano silica sol was added to 30 kg of polyurethane acrylate while stirring. After the addition was complete, the mixture was stirred at 500 rpm for 10 min. Then, 1 kg of 2-hydroxy-2-methyl-1-phenylpropanone (photoinitiator) was added and mixed thoroughly. The mixture was then stirred at 800 rpm for 30 min in a 50°C water bath until it was fully mixed.

[0033] Example

[0034] Example 1

[0035] A composite ceramic material for teaching model teeth is prepared by the following steps: (1) Preparation of matrix slurry: Mix 50 kg of pentaerythritol tetrakis(3-mercaptopropionic acid) with 25 kg of triallyl isocyanurate, stir at 300 rpm for 25 min in a 60°C water bath, keeping the reaction vessel sealed during stirring to obtain a mixture; Take 20 kg of zinc polyacrylate and stir it into propylene glycol methyl ether acetate solvent pre-cooled to 10°C. Shear at 8000 rpm for 15 min, then mix with the mixture cooled to 30°C. Stir at 300 rpm for 60 min, add 0.35 kg of benzoin dimethyl ether, and add propylene glycol methyl ether acetate to a solid content of 40%. Stir at 300 rpm for 10 min, then vacuum degas at 0.1 MPa for 15-20 min until the slurry viscosity is 1200 mPa·s to form the matrix slurry. (2) Layered slurry preparation: Inner layer slurry: Take 10 kg of the matrix slurry after vacuum degassing treatment, add 6 kg of nano hydroxyapatite and 0.15 kg of phosphoric acid esterified diphenylphosphine oxide (photoinitiator) in sequence, mix and stir evenly to obtain the inner layer slurry; Outer layer slurry: After vacuum degassing, 10 kg of matrix slurry was sequentially mixed with 4 kg of nano silica, 0.05 kg of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (photoinitiator), and 0.02 kg of fluorescent whitening agent CBS-X to obtain the outer layer slurry. (3) Layer-by-layer photopolymerization molding is adopted using photopolymerization 3D printing technology. The inner and outer layers of slurry are loaded into the corresponding material tanks of the 3D printer. According to the three-dimensional design data of the model tooth, the slurry is printed and cured layer by layer to construct the model tooth structure. During the printing process, the printing layer thickness is controlled to be 0.2 mm, the curing energy density of the inner layer is 40 mJ / cm², and the curing energy density of the outer layer is 22 mJ / cm². (4) Low-temperature curing: The printed model teeth were placed in an ultraviolet curing chamber and cured at 55°C for 2.5 hours. During the curing process, the curing degree of the model teeth was checked regularly to ensure that they were completely cured. The nano-silica sol-polyurethane composite coating prepared in Example 1 was sprayed onto its surface at a coating amount of 5 mg / cm³.2 The nano-hydroxyapatite has a particle size of 50-70 nm, and the silica has a particle size of 15-25 nm.

[0036] Example 2

[0037] A composite ceramic material for teaching model teeth is prepared by the following steps: (1) Preparation of matrix slurry: 40 kg of pentaerythritol tetrakis(3-mercaptopropionic acid) ester and 30 kg of triallyl isocyanurate were mixed and stirred at 200 rpm for 30 min in a 55°C water bath. During the stirring process, the reaction vessel was kept sealed to obtain the mixture. Take 15 kg of zinc polyacrylate and stir it into propylene glycol methyl ether acetate solvent pre-cooled to 10°C. Shear at 8000 rpm for 15 min, then mix with the mixture cooled to 30°C. Stir at 300 rpm for 60 min, add 0.2 kg of benzoin dimethyl ether, and add propylene glycol methyl ether acetate to a solid content of 40%. Stir at 300 rpm for 10 min, then vacuum degas at 0.1 MPa for 20 min until the slurry viscosity is 1200 Pa·s to form the matrix slurry. (2) Layered slurry preparation: Inner layer slurry: Take 9 kg of the matrix slurry after vacuum degassing treatment, add 6.5 kg of nano hydroxyapatite and 0.1 kg of phosphoric acid esterified diphenylphosphine oxide (photoinitiator) in sequence, mix and stir evenly to obtain the inner layer slurry; Outer layer slurry: After vacuum degassing, 11 kg of matrix slurry was sequentially mixed with 4.5 kg of nano silica, 0.04 kg of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (photoinitiator), and 0.01 kg of fluorescent whitening agent CBS-X to obtain the outer layer slurry. (3) Layer-by-layer photopolymerization molding is adopted using photopolymerization 3D printing technology. The inner and outer layers of slurry are loaded into the corresponding material tanks of the 3D printer. According to the three-dimensional design data of the model tooth, the slurry is printed and cured layer by layer to construct the model tooth structure. During the printing process, the printing layer thickness is controlled to be 0.2 mm, the curing energy density of the inner layer is 40 mJ / cm², and the curing energy density of the outer layer is 22 mJ / cm². (4) Low-temperature curing: The printed model teeth were placed in an ultraviolet curing chamber and cured at 60°C for 2 hours. During the curing process, the curing degree of the model teeth was checked regularly to ensure that they were completely cured. The nano-silica sol-polyurethane composite coating prepared in Example 2 was sprayed onto its surface at a coating amount of 5 mg / cm³. 2 The nano-hydroxyapatite has a particle size of 50-70 nm, and the silica has a particle size of 15-25 nm.

[0038] Example 3

[0039] A composite ceramic material for teaching model teeth is prepared by the following steps: (1) Preparation of matrix slurry: 60 kg of pentaerythritol tetrakis(3-mercaptopropionic acid) ester and 20 kg of triallyl isocyanurate were mixed and stirred at 250 rpm for 20 min in a water bath at 65 °C. During the stirring process, the reaction vessel was kept sealed to obtain the mixture. Take 25 kg of zinc polyacrylate and stir it into propylene glycol methyl ether acetate solvent pre-cooled to 10°C. Shear at 8000 rpm for 15 min, then mix with the mixture cooled to 30°C. Stir at 300 rpm for 60 min, add 0.5 kg of benzoin dimethyl ether, and add propylene glycol methyl ether acetate to a solid content of 40%. Stir at 300 rpm for 10 min, then vacuum degas at 0.1 MPa for 20 min until the slurry viscosity is 1200 mPa·s to form the matrix slurry. (2) Layered slurry preparation: Inner layer slurry: Take 11 kg of the matrix slurry after vacuum degassing treatment, add 5.5 kg of nano hydroxyapatite and 0.2 kg of phosphoric acid esterified diphenylphosphine oxide (photoinitiator) in sequence, mix and stir evenly to obtain the inner layer slurry; Outer layer slurry: After vacuum degassing, 9 kg of matrix slurry was sequentially mixed with 3.5 kg of nano silica, 0.06 kg of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (photoinitiator), and 0.03 kg of fluorescent whitening agent CBS-X to obtain the outer layer slurry. (3) Layer-by-layer photopolymerization molding is adopted using photopolymerization 3D printing technology. The inner and outer layers of slurry are loaded into the corresponding material tanks of the 3D printer. According to the three-dimensional design data of the model tooth, the slurry is printed and cured layer by layer to construct the model tooth structure. During the printing process, the printing layer thickness is controlled to be 0.2 mm, the curing energy density of the inner layer is 40 mJ / cm², and the curing energy density of the outer layer is 22 mJ / cm². (4) Low-temperature curing: The printed model teeth were placed in an ultraviolet curing chamber and cured at 50°C for 3 hours. During the curing process, the curing degree of the model teeth was checked regularly to ensure that they were completely cured. The nano-silica sol-polyurethane composite coating prepared in Example 3 was sprayed onto its surface at a coating amount of 5 mg / cm³. 2 The nano-hydroxyapatite has a particle size of 50-70 nm, and the silica has a particle size of 15-25 nm.

[0040] Example 4

[0041] A composite ceramic material for teaching model teeth, differing from Example 1 in that the nano-hydroxyapatite and nano-silica added in this example have undergone pretreatment: 7 kg of nano-hydroxyapatite was added to 20 kg of 5 wt% γ-(methacryloyloxy)propyltrimethoxysilane ethanol solution, ultrasonicated at 300 W for 30 min, filtered, and dried at 60 °C for 5 h to obtain pretreated nano-hydroxyapatite. 9.8 kg of nano-silica and 0.2 kg of isopropyltris(dioctylpyrophosphoryloxy)titanate were added to a ball mill jar, with an appropriate amount of zirconia grinding balls pre-placed in the jar, the mass ratio of the balls to the powder being 4:1; the mixture was ball-milled at 300 rpm for 10 min to obtain pretreated nano-silica; the remaining steps were the same as in Example 1.

[0042] Example 5

[0043] A composite ceramic material for teaching model teeth, which differs from Example 1 in that 1 kg of yttrium fluoride is added to the outer slurry of this example: Outer layer slurry: After vacuum degassing, 10 kg of matrix slurry was sequentially mixed with 4 kg of nano silica, 1 kg of yttrium fluoride, 0.05 kg of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (photoinitiator), and 0.02 kg of fluorescent whitening agent CBS-X to obtain the outer layer slurry; the remaining steps were the same as in Example 1.

[0044] Example 6

[0045] A composite ceramic material for teaching model teeth differs from Example 5 in that 0.5 kg of yttrium fluoride is added to the outer slurry of this example.

[0046] Example 7

[0047] A composite ceramic material for teaching model teeth differs from Example 5 in that 1.5 kg of yttrium fluoride is added to the outer slurry of this example.

[0048] Example 8

[0049] A composite ceramic material for teaching model teeth differs from Example 1 in that the surface of the model teeth in this example is not coated with a nano-silica sol-polyurethane composite coating.

[0050] Example 9

[0051] A composite ceramic material for teaching model teeth differs from Example 1 in that the amount of nano-silica sol-polyurethane composite coating sprayed onto the surface of the model teeth in this example is 6 mg / cm³. 2 .

[0052] Example 10

[0053] A composite ceramic material for teaching model teeth differs from Example 1 in that the amount of nano-silica sol-polyurethane composite coating sprayed onto the surface of the model teeth in this example is 4 mg / cm³. 2 .

[0054] Comparative Example

[0055] Comparative Example 1 A composite ceramic material for teaching model teeth, differing from Example 1 in that a single-layer homogeneous slurry is used in this comparative example, and its preparation includes the following steps: (1) Preparation of matrix slurry: Mix 50 kg of pentaerythritol tetrakis(3-mercaptopropionic acid) with 25 kg of triallyl isocyanurate, stir at 300 rpm for 25 min in a 60°C water bath, keeping the reaction vessel sealed during stirring to obtain a mixture; Take 20 kg of zinc polyacrylate and stir it into propylene glycol methyl ether acetate solvent pre-cooled to 10°C. Shear at 8000 rpm for 15 min, then mix with the mixture cooled to 30°C. Stir at 300 rpm for 60 min, add 0.35 kg of benzoin dimethyl ether, and add propylene glycol methyl ether acetate to a solid content of 40%. Stir at 300 rpm for 10 min, then vacuum degas at 0.1 MPa for 15-20 min until the slurry viscosity is 1200 mPa·s to form the matrix slurry. (2) Slurry preparation: Take 20 kg of the matrix slurry after vacuum degassing treatment and add 6 kg of nano hydroxyapatite, 4 kg of nano silica, 0.02 kg of fluorescent whitening agent CBS-X and 0.15 kg of phosphoric acid esterified diphenylphosphine oxide (photoinitiator) in sequence and mix them evenly to obtain the slurry; (3) Layered photopolymerization molding is performed using photopolymerization 3D printing technology. The slurry is loaded into the corresponding material tank of the 3D printer. Based on the three-dimensional design data of the model tooth, the slurry is printed and cured to construct the model tooth structure. During the printing process, the curing energy density is 40mJ / cm². (4) Low temperature curing: Place the printed model teeth in an ultraviolet curing chamber and cure for 2.5 hours under thermal synergy conditions at 55℃. During the curing process, check the curing degree of the model teeth regularly to ensure that they are completely cured.

[0056] Comparative Example 2 A composite ceramic material for teaching model teeth differs from Example 1 in that a modified epoxy acrylic resin is used as the matrix resin in this comparative example, as detailed below: (1) Preparation of matrix slurry: Take 20 kg of zinc polyacrylate and stir it into propylene glycol methyl ether acetate solvent pre-cooled to 10℃. Shear at 8000 rpm for 15 min, then mix with 75 kg of modified epoxy acrylic resin. Stir at 300 rpm for 60 min, add 0.35 kg of benzoin dimethyl ether, add propylene glycol methyl ether acetate to the solid content of 40%, stir at 300 rpm for 10 min, and then vacuum degas at 0.1 MPa for 15-20 min until the slurry viscosity is 1200 mPa·s to form matrix slurry; The remaining steps are the same as in Example 1.

[0057] Comparative Example 3 A composite ceramic material for teaching model teeth, which differs from Example 1 in that in step (4) of this comparative example, the printed model teeth are placed in an ultraviolet curing chamber and cured at 80°C for 2.5 hours.

[0058] Performance testing

[0059] Wear resistance: After being drilled 50 times with a dental teaching tungsten carbide bur (1.6 mm in diameter) at a pressure of 3 N and a speed of 20,000 rpm, the Vickers hardness retention rate of the surface was tested. Color fastness: Disinfect by immersion in 1% sodium hypochlorite solution 100 times (10 minutes each time), and measure the color difference using a spectrophotometer; Self-healing: A Vickers indenter was used on the surface of the model tooth to simulate a local impact with a load of 100g and a holding time of 15s, forming a scratch with a length of 10mm and a depth of 20±2μm. After standing in a 60℃ oven for 2 hours, the scratch repair rate was tested. Bending strength: The bending strength of the model teeth was tested using the three-point bending method.

[0060] Table 1 Test Data

[0061] Combining Examples 1-3 and Comparative Example 1 with the data in Table 1, it can be seen that the experimental data of Examples 1-3 are all better than those of Comparative Example 1. This indicates that the use of a layered slurry design, with the inner layer simulating the flexibility and biocompatibility of dentin and the outer layer simulating the hardness and wear resistance of enamel, creates a biomimetic tooth gradient structure, giving the model tooth both high strength and high toughness. In contrast, Comparative Example 1 uses a single-layer homogeneous slurry, which cannot form such a gradient structure, resulting in poor performance of the model tooth in terms of wear resistance, color fastness, and self-healing properties.

[0062] Combining Examples 1-3 and Comparative Example 2 with the data in Table 1, it can be seen that the experimental data of Examples 1-3 are all better than those of Comparative Example 2. This indicates that the matrix system formed by pentaerythritol tetrakis(3-mercaptopropionic acid) and triallyl isocyanurate in this application has advantages in terms of wear resistance and self-healing. Applying it to the preparation of model teeth can yield model teeth with good wear resistance and high self-healing ability.

[0063] Combining Examples 1-3 and Comparative Example 3 with the data in Table 1, it can be seen that the experimental data of Examples 1-3 are better than those of Comparative Example 3. This indicates that the appropriate curing temperature also affects the performance of the model tooth. Maintaining the curing temperature at 50-70℃ is conducive to the formation of covalent bond network and zinc ion coordination bond network, as well as the stable construction of gradient structure, thereby improving the various properties of the model tooth.

[0064] Combining Examples 1 and 4 with the data in Table 1, it can be seen that the experimental data of Example 4 are all better than those of Example 1. This indicates that further processing of nano-hydroxyapatite and nano-silica can enhance their bonding with the matrix and improve their dispersibility, thereby improving the wear resistance, color fastness and self-healing properties of the model teeth.

[0065] Combining Examples 1 and 5-7 with the data in Table 1, it can be seen that the experimental data of Examples 5-7 are all better than those of Example 1, indicating that the addition of yttrium fluoride has a positive effect on the various properties of the model teeth.

[0066] Combining Examples 1 and 8 with the data in Table 1, it can be seen that all experimental data in Example 1 are better than those in Example 8, indicating that the coating of the nano-silica sol-polyurethane composite coating can further form a protective film on the surface of the model tooth, thereby improving the hardness and wear resistance of the model tooth.

[0067] Combining Examples 1 and 9-10 with the data in Table 1, it can be seen that the experimental data of Example 1 are all superior to those of Examples 9-10, indicating that the spraying amount of the nano-silica sol-polyurethane composite coating is within 5 mg / cm³. 2 The optimal time is when the bonding interface is formed, which can not only form a good bonding interface, but also further enhance and improve the various properties of the model teeth.

[0068] The model teeth prepared by this application reduce the frequency of replacement from once per semester to once every two academic years, greatly reducing teaching costs.

[0069] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing a composite ceramic material for teaching model teeth, characterized in that, Includes the following steps: (1) Preparation of matrix slurry: Pentaerythritol tetrakis(3-mercaptopropionic acid) and triallyl isocyanurate are mixed and stirred in a water bath at 200-300 rpm for 20-30 min at 55-65℃ to obtain a mixture; Zinc polyacrylate is added to propylene glycol methyl ether acetate solvent and stirred to disperse evenly, and then mixed with the mixture. Benzoin dimethyl ether is added and stirred evenly. Propylene glycol methyl ether acetate solvent is added to a solid content of 40%. The mixture is stirred in a water bath at 200-300 rpm for 2-3 hours at 55-65℃. After vacuum degassing, the matrix slurry is formed. (2) Layered slurry preparation: Inner layer slurry: Take the matrix slurry after vacuum degassing treatment, add nano hydroxyapatite and photoinitiator in sequence, mix and stir evenly to obtain the inner layer slurry; Outer layer slurry: After vacuum degassing, nano-silica, photoinitiator and fluorescent whitening agent are added to the matrix slurry in sequence and stirred evenly to obtain the outer layer slurry; (3) The model is constructed by layering photopolymerization 3D printing technology and solidifying the slurry layer by layer. (4) Low temperature curing: Curing under ultraviolet light at 50-70℃ for 2-3 hours.

2. The method for preparing a composite ceramic material for teaching model teeth according to claim 1, characterized in that: The matrix slurry comprises the following raw materials in parts by weight: 40-60 parts of pentaerythritol tetrakis(3-mercaptopropionic acid), 20-30 parts of triallyl isocyanurate, 0.2-0.5 parts of dimethyl benzoate, and 15-25 parts of zinc polyacrylate.

3. The method for preparing a composite ceramic material for teaching model teeth according to claim 1, characterized in that: The inner layer slurry comprises the following raw materials in parts by weight: 90-110 parts of matrix slurry, 55-65 parts of nano-hydroxyapatite, and 1-2 parts of photoinitiator; The outer layer slurry comprises the following raw materials in parts by weight: 90-110 parts of matrix slurry, 35-45 parts of nano-silica, 0.4-0.6 parts of photoinitiator, and 0.1-0.3 parts of fluorescent whitening agent.

4. The method for preparing a composite ceramic material for teaching model teeth according to claim 1, characterized in that: The nano-hydroxyapatite undergoes a pretreatment process before being added, specifically as follows: the nano-hydroxyapatite is ultrasonically treated in a 5wt% γ-(methacryloyloxy)propyltrimethoxysilane ethanol solution for 20-30 minutes, then removed and dried to obtain pretreated nano-hydroxyapatite. The nano-silica undergoes a pretreatment process before being added, specifically as follows: nano-silica and isopropyltris(dioctylpyrophosphoryloxy)titanate are mixed at a mass ratio of 96-98:2 and ball-milled for 10-15 minutes to obtain pretreated nano-silica.

5. The method for preparing a composite ceramic material for teaching model teeth according to claim 1, characterized in that: After low-temperature curing, a nano-silica sol-polyurethane composite coating is sprayed onto the surface. The coating includes the following raw materials in parts by weight: 40-60 parts of nano-silica sol, 30-50 parts of polyurethane acrylate, and 1-4 parts of photoinitiator.

6. The method for preparing a composite ceramic material for teaching model teeth according to claim 5, characterized in that: The preparation of the nano-silica sol-polyurethane composite coating includes the following steps: The nano-silica sol is mixed with polyurethane acrylate, a photoinitiator is added, and the mixture is stirred at 500-800 rpm for 30-60 minutes in a water bath at 40-50℃ until fully mixed.

7. The method for preparing a composite ceramic material for teaching model teeth according to claim 5, characterized in that: The composite coating was applied to the surface of the model tooth at a rate of 5 mg / cm². 2 .

8. The method for preparing a composite ceramic material for teaching model teeth according to claim 1, characterized in that: The outer slurry also contains 0.5-1.5 parts of yttrium fluoride.

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