A tooth enamel veneer repair material and preparation method thereof

Abstract

This invention provides a dental enamel veneer restorative material and its preparation method, belonging to the technical field of ceramic molding products. To further improve the adhesion of dental veneer materials, reduce the amount of tooth structure removed, and decrease the risk of chipping and detachment, this invention uses zirconium oxide, alumina, hydroxyapatite, dimethylsilylated silica, silicon dioxide, fluorapatite, magnesium oxide, thermosetting acrylic resin, aluminum hydroxide gel, silane coupling agent, polyvinyl alcohol, and sodium inositol hexaphosphate as raw materials. These components are combined in specific proportions, and a special process is used to prepare the dental veneers. While ensuring good biocompatibility, high hardness, and wear resistance, this invention further improves adhesion, reduces the amount of tooth structure removed, decreases the risk of chipping and detachment, extends service life, and provides a better user experience.

Description

Technical Field

[0001] This invention belongs to the field of ceramic molding technology, specifically relating to a dental enamel veneer restorative material and its preparation method. Background Art

[0002] In daily life, poor oral hygiene habits, dietary habits, and accidental injuries can all lead to various dental problems. For example, long-term consumption of colored beverages such as coffee and tea, or bad habits like smoking, can easily stain the surface of teeth, affecting their appearance. Furthermore, cavities, tooth wear, and trauma can also damage the shape and structure of teeth. Tooth defects and discoloration are becoming increasingly common. While traditional restorative methods such as fillings can solve some problems, they are often unsatisfactory in terms of aesthetics and durability.

[0003] Having straight, white teeth not only contributes to oral health but also enhances personal image and self-confidence. In social and professional settings, aesthetically pleasing teeth are becoming an increasingly important requirement. As people pay more attention to oral health and aesthetics, the demands on dental restoration techniques are also rising. With the continuous development of dental restoration technology, enamel veneers (i.e., dental veneers) have emerged and play a vital role in the field of oral medicine. Enamel veneers can significantly improve the appearance of teeth without damaging excessive tooth structure, satisfying people's pursuit of beauty. For example, patent CN208031312U discloses a dental veneer that wraps around the tooth surface, protecting the teeth while improving aesthetics.

[0004] The main types of dental veneers currently available include resin veneers, porcelain veneers, and hard resin veneers. Resin veneers are inexpensive, but suffer from poor durability, are prone to aging and discoloration, are easily worn down, and are difficult to clean. Porcelain veneers are highly wear-resistant, less likely to cause allergies, and have a stable and aesthetically pleasing color. However, they require a relatively large amount of tooth structure to be removed, which can cause tooth sensitivity. Ceramic veneers may chip when subjected to significant impact or biting hard objects, leading to high replacement costs. While hard resin veneers offer better wear resistance than resin veneers, they are still slightly inferior to porcelain veneers in terms of aesthetics and durability. They still require the removal of a significant amount of tooth structure, which can cause tooth sensitivity.

[0005] Therefore, it is necessary to develop new dental veneer materials that, while ensuring good biocompatibility, high hardness, and wear resistance, further improve adhesion, reduce the amount of tooth structure removed, reduce the risk of chipping and falling off, and provide a better user experience. Summary of the Invention

[0006] To further improve the adhesion of dental veneer materials, reduce the amount of tooth structure removed, and decrease the risk of chipping and detachment, thus providing a better user experience, this invention provides a dental enamel veneer restorative material and its preparation method. The material uses zirconium oxide, alumina, hydroxyapatite, dimethyl silyl silica, silica, fluorapatite, magnesium oxide, thermosetting acrylic resin, aluminum hydroxide gel, silane coupling agent, polyvinyl alcohol, and sodium inositol hexaphosphate as raw materials. These components are blended in specific proportions, and a special process is used to prepare the dental veneers. While ensuring good biocompatibility, high hardness, and wear resistance, this method further improves adhesion, reduces the amount of tooth structure removed, decreases the risk of chipping and detachment, extends service life, and provides a better user experience. The specific technical solution is as follows:

[0007] A dental enamel veneer restorative material comprises the following raw materials in parts by weight: 60-70 parts zirconium oxide, 15-20 parts alumina, 8-12 parts hydroxyapatite, 5-8 parts dimethylsilylated silica, 3-6 parts silica, 0.1-0.5 parts fluorapatite, 0.3-0.5 parts magnesium oxide, 3-6 parts thermosetting acrylic resin, 3-5 parts aluminum hydroxide gel, 1.5-3 parts silane coupling agent, 0.5-1.5 parts polyvinyl alcohol, and 0.5-1.5 parts sodium inositol hexaphosphate.

[0008] In the above technical solution, the particle size of zirconium oxide, aluminum oxide, hydroxyapatite, silicon dioxide, fluorapatite and magnesium oxide are all in the nanoscale.

[0009] In the above technical solution, the particle size range of the dimethylsilylated silica is 0.3μm to 2μm.

[0010] In the above technical solution, the thermosetting acrylic resin is liquid and its model number is HK87010.

[0011] In the above technical solution, the silane coupling agent is of type KH-560, and the particle size of both polyvinyl alcohol and sodium inositol hexaphosphate is nanoscale.

[0012] The preparation method of the above-mentioned enamel veneer restorative material includes the following steps:

[0013] S1: Zirconium oxide, aluminum oxide, hydroxyapatite, silicon dioxide, fluorapatite and magnesium oxide were premixed uniformly according to the mass fractions to obtain mixture A; polyvinyl alcohol and sodium inositol hexaphosphate were premixed uniformly to obtain mixture B; dimethyl silyl alkyl silicate was uniformly dispersed in thermosetting acrylic resin and vacuumed to obtain modified product C.

[0014] S2: Mix mixture A and mixture B evenly, then add aluminum hydroxide gel and silane coupling agent, mix evenly, then add modifier C, mix evenly to obtain the base material;

[0015] S3: The base material is molded and then subjected to cold pressing, isostatic pressing, medium-temperature heat treatment, and high-temperature heat treatment in sequence to obtain the formed dental veneer, i.e., enamel veneer restoration material.

[0016] In step S3 of the above preparation method, the cold pressing pressure is 8MPa to 15MPa, the cold pressing time is 8s to 15s, and the cold pressing temperature is 80℃ to 90℃.

[0017] In step S3 of the above preparation method, the isostatic pressure is 260MPa to 280MPa, the isostatic pressing time is 50s to 80s, and the isostatic pressing temperature is 120℃ to 150℃.

[0018] In step S3 of the above preparation method, the temperature of the medium-temperature heat treatment is 600℃~800℃, and the time of the medium-temperature heat treatment is 30min~60min.

[0019] In step S3 of the above preparation method, the temperature of the high-temperature heat treatment is 1200℃~1400℃, and the time of the high-temperature heat treatment is 60min~90min.

[0020] The enamel veneer restorative material and its preparation method provided by this invention have the following advantages compared with the prior art:

[0021] I. The enamel veneer restoration material of this invention uses zirconium oxide, alumina, hydroxyapatite, dimethylsilyl alkyl silicate, silica, fluorapatite, magnesium oxide, thermosetting acrylic resin, aluminum hydroxide gel, silane coupling agent, polyvinyl alcohol, sodium inositol hexaphosphate, etc. as raw materials. Various components are combined in a certain proportion to prepare dental veneers. While ensuring good biocompatibility, high hardness, and wear resistance, it can further improve adhesion, reduce the amount of tooth structure removed, reduce the risk of porcelain chipping and falling off, extend service life, and provide a better user experience.

[0022] II. The addition of alumina to zirconia ceramics can enhance the overall strength and hardness of the composite material to a certain extent, making dental veneers more wear-resistant and impact-resistant in daily use, thus extending their service life. The addition of alumina can improve the microstructure of zirconia ceramics, inhibit crack propagation, thereby increasing the material's toughness and reducing the risk of dental veneers breaking under biting forces. Alumina can act as a flux, lowering the sintering temperature of zirconia ceramics to a certain extent and accelerating the sintering time of the ceramic material. This helps reduce energy consumption and production costs, while also alleviating the high-temperature requirements on equipment and reducing the structural impact of high temperatures on other composite components. Appropriate amounts of alumina can improve the fluidity and formability of zirconia ceramic slurry, making it easier to achieve uniform shape and size during the manufacturing process, improving product quality and precision. By adjusting the alumina content and the ratio of other additives, the color and transparency of the dental veneers can be fine-tuned to better match the appearance of natural teeth, achieving a more natural and aesthetically pleasing restorative effect. The presence of aluminum oxide makes the surface of dental veneers smoother and more delicate, reducing the occurrence of surface defects such as pores and cracks, and improving the appearance quality and aesthetic performance of the veneers.

[0023] Third, hydroxyapatite has excellent biocompatibility with human tissues and will not cause allergic or rejection reactions. Adding it to zirconia ceramic dental veneers can improve overall biocompatibility, reduce irritation to oral tissues, and decrease the risk of adverse reactions. Hydroxyapatite is a major inorganic component of teeth. For demineralized areas of the tooth surface caused by cavities, the addition of hydroxyapatite provides calcium and phosphorus ions in the oral environment, which helps the remineralization process of the tooth surface, allowing damaged enamel to be repaired and strengthened to a certain extent, improving the tooth's resistance to cavities. Hydroxyapatite can improve the microstructure of zirconia ceramics, inhibit crack propagation, thereby improving the material's toughness and reducing the risk of dental veneers breaking under biting forces. The color of hydroxyapatite is similar to the natural color of teeth; adding it to zirconia ceramics makes the color of dental veneers more natural and realistic, blending better with the surrounding natural teeth and improving the aesthetic effect after restoration.

[0024] IV. Dimethyl silyl silica increases the silicon content on the surface of zirconia ceramics, making it easier for them to react chemically with adhesives and form strong chemical bonds. This improves the bonding strength between the veneer and the tooth surface, reduces the risk of veneer detachment, and effectively reduces the amount of tooth tissue removed. Appropriate amounts and particle sizes of dimethyl silyl silica help improve the wettability of the zirconia ceramic surface, allowing the adhesive to spread and penetrate better, further enhancing the bonding effect. Appropriate addition of dimethyl silyl silica can effectively reduce the coefficient of thermal expansion of ceramic dental veneers. When used in combination with other ingredients, it can improve the anti-aging properties of ceramic dental veneers; it also helps with the color stability of dental veneers, reducing fading or discoloration caused by various factors in the oral environment (such as food, beverages, and oral secretions).

[0025] Fifth, silica can act as a dispersion reinforcement in the zirconia ceramic matrix, inhibiting crack propagation, improving the strength and toughness of dental veneers, making them better able to withstand chewing pressure, and reducing the risk of breakage or damage. Adding an appropriate amount of silica can increase the material's hardness, making it more wear-resistant, and can also adjust the elastic modulus, making the dental veneers more mechanically compatible with natural teeth, providing a more comfortable user experience.

[0026] The silanol groups (-Si-OH) formed on the veneer surface react chemically with the active ingredients in the adhesive to form chemical bonds, thereby increasing the adhesion strength between the veneer and the tooth surface and reducing the possibility of veneer detachment. Silica can also adjust the transparency and color of the veneer, making it better mimic the appearance of natural teeth.

[0027] VI. Fluoroapatite, structurally similar to hydroxyapatite, a natural component of human teeth, exhibits excellent biocompatibility. Adding it to zirconia ceramic dental veneers allows them to integrate more harmoniously with oral tissues, reducing irritation and adverse reactions to the oral mucosa and other tissues. In the oral environment, fluoride ions are released from fluoroapatite and combine with minerals such as calcium and phosphorus on the tooth surface, promoting remineralization of the tooth's hard tissues, enhancing the tooth's resistance to caries, and helping to prevent caries lesions in the surrounding tooth tissues. Fluoroapatite acts as a diffuse reinforcing agent within the zirconia ceramic matrix, inhibiting crack propagation, improving the strength and toughness of the dental veneers, making them more able to withstand chewing pressure, and reducing the risk of breakage or damage. The refractive index and other optical properties of fluoroapatite, combined with zirconia ceramics, allow for better light transmission and scattering, making the color and transparency of the dental veneers closer to natural teeth.

[0028] VII. Magnesium oxide acts as a stabilizer. When incorporated into zirconia crystals, it transforms the crystal structure of zirconia from the monoclinic phase (m) to the tetragonal phase (t), ensuring crystal stability at different temperatures, especially during high-temperature cycling. This improves the stability and anti-aging properties of dental veneers. Simultaneously, it inhibits grain growth, increasing the density of the veneers, making them more compact and thus enhancing strength and toughness, better withstanding chewing pressure. Magnesium oxide also exhibits good biocompatibility with human tissues. Adding it to zirconia ceramic dental veneers allows them to integrate more harmoniously with oral tissues, reducing irritation and adverse reactions to the oral mucosa and other tissues.

[0029] 8. Adding thermosetting acrylic resin to zirconia ceramic dental veneers has the following main effects: Thermosetting acrylic resin has excellent bonding properties, which can increase the compaction density of the base material, ensuring a tight bond between the various components. It can also fill the pores on the particle surface and between particles, eliminating air bubbles and improving the performance of the dental veneers. After short-time sintering, thermosetting acrylic resin exhibits good bonding with other components, increasing the toughness of the zirconia ceramic dental veneers, making them more able to withstand various mechanical forces in the oral cavity, reducing the risk of veneer breakage or damage, and enhancing resistance to microcracks and durability. After heat treatment, volatile substances in the thermosetting acrylic resin are released, making it safe and non-irritating, and it does not affect the color and aesthetics.

[0030] 9. Aluminum hydroxide gel can increase the compaction density of materials, fill the pores on the particle surface and between particles, eliminate air bubbles, improve the compaction quality of the base material, participate in the reaction during heat treatment sintering, help improve the sintering density of ceramic dental veneers, improve flexural strength, Vickers hardness, fracture toughness, and reduce the coefficient of thermal expansion.

[0031] Aluminum hydroxide gel helps disperse and alleviate stress concentration within zirconia ceramics, reducing the generation and propagation of cracks caused by stress concentration, and improving the overall strength and durability of dental veneers. The components retained after heat treatment of the aluminum hydroxide gel allow it to interact more harmoniously with human oral tissues, reducing irritation and adverse reactions to the oral mucosa and other tissues, and lowering the risk of allergies.

[0032] 10. Some functional groups (such as alkoxy groups) in the silane coupling agent molecule can undergo hydrolysis with the hydroxyl groups on the surface of zirconia ceramics to form chemical bonds, making them tightly bonded; the other organic functional group can react with the adhesive resin, thus building a "bridge" between the zirconia ceramic and the adhesive, firmly connecting the two materials with different properties, greatly improving the bonding strength and preventing the dental veneers from falling off in the oral cavity. Silane coupling agents can reduce the surface tension between zirconia ceramics and the adhesive, allowing the adhesive to better wet the zirconia ceramic surface, increasing the contact area, and further improving the bonding effect. They can, to a certain extent, prevent moisture from penetrating to the bonding interface, reducing problems such as adhesive aging and degradation caused by moisture, thereby improving the durability of dental veneer restorations and extending their service life. The oral environment is complex, containing saliva, food debris, bacteria, etc. Silane coupling agents can enhance the stability of the adhesive and zirconia ceramic in the oral environment, allowing them to better withstand the effects of chewing forces, temperature changes, and other factors, maintaining long-term bonding performance.

[0033] XI. In the fabrication of dental veneers, polyvinyl alcohol (PVA) serves as an auxiliary material, aiding in the better molding of zirconia ceramics and improving production efficiency and product quality. PVA improves the surface compatibility of particulate materials. During mixing and pressurization, PVA facilitates the combination of particulate materials with thermosetting acrylic resins and silane coupling agents, enhancing molding quality. PVA interacts with components in thermosetting acrylic resins and silane coupling agents, regulating properties such as viscosity and flowability. This allows for easier expulsion of gas and excess liquid from the base material under pressure, ensuring thorough and uniform liquid filling and improving the uniformity of cold pressing and isostatic pressing molding. Furthermore, PVA regulates the drying speed of the material, preventing cracking caused by excessively rapid drying and ensuring greater stability of the dental veneers during heat treatment drying.

[0034] 12. Sodium inositol hexaphosphate can reduce the adhesion of oral bacteria to the surface of dental veneers, lowering the risk of oral diseases such as tooth decay and periodontitis. By interacting with ions or proteins on the bacterial surface, it alters the surface properties of the bacteria, making it difficult for them to adhere to the veneers, thus inhibiting the formation of tartar. As an antioxidant, sodium inositol hexaphosphate can protect zirconia ceramics and tooth tissue from oxidative stress damage, maintaining the stability and color durability of dental veneers. The sintering reaction of sodium inositol hexaphosphate significantly improves the anti-aging properties of ceramic dental veneers.

[0035] Thirteen, in the preparation method of this invention, dimethylsilylated silica is first uniformly dispersed in thermosetting acrylic resin, and vacuum is applied to obtain modified material C; the thermosetting acrylic resin pre-modifies the surface of dimethylsilylated silica, the gas is expelled, and a layer of thermosetting acrylic resin adheres to the surface, which can improve the surface adhesion of dimethylsilylated silica and the bonding between the two, better exert the superimposed effect of dimethylsilylated silica and thermosetting acrylic resin, and make the quality and stress of the dental veneer more uniform after final mixing, thereby further improving the performance of the dental veneer.

[0036] Fourteen, the temperature design of cold pressing and isostatic pressing in this invention can improve the compaction and bonding of the base material, the uniformity and smoothness of liquid drainage, and the compaction homogeneity, thereby improving the quality of medium-temperature heat treatment and high-temperature heat treatment, and thus enhancing the performance of dental veneers. Detailed Implementation

[0037] The present invention will be further described below with reference to specific implementation examples, but the present invention is not limited to these embodiments.

[0038] Example 1

[0039] A dental enamel veneer restorative material comprises the following raw materials in parts by weight: 65 parts zirconium oxide, 18 parts aluminum oxide, 10 parts hydroxyapatite, 6.5 parts dimethylsilylated silica, 5 parts silica, 0.3 parts fluorapatite, 0.4 parts magnesium oxide, 4.5 parts thermosetting acrylic resin, 4 parts aluminum hydroxide gel, 2.5 parts silane coupling agent, 1 part polyvinyl alcohol, and 1 part sodium inositol hexaphosphate.

[0040] The preparation method of the above-mentioned enamel veneer restorative material includes the following steps:

[0041] S1: Zirconium oxide, aluminum oxide, hydroxyapatite, silicon dioxide, fluorapatite and magnesium oxide were premixed uniformly according to the mass fractions to obtain mixture A; polyvinyl alcohol and sodium inositol hexaphosphate were premixed uniformly to obtain mixture B; dimethyl silyl alkyl silicate was uniformly dispersed in thermosetting acrylic resin and vacuumed to obtain modified product C.

[0042] S2: Mix mixture A and mixture B evenly, then add aluminum hydroxide gel and silane coupling agent, mix evenly, then add modifier C, mix evenly to obtain the base material;

[0043] S3: The base material is molded and cold-pressed at a pressure of 12 MPa for 10 seconds at a temperature of 85°C. Then, isostatic pressing is performed at a pressure of 270 MPa for 60 seconds at a temperature of 130°C. After that, it is subjected to medium-temperature heat treatment at 700°C for 45 minutes, followed by high-temperature heat treatment at 1300°C for 75 minutes. After cooling, trimming, polishing, and cleaning, the formed dental veneer, i.e., enamel veneer restoration material, is obtained.

[0044] Example 2

[0045] A dental enamel veneer restorative material comprises the following raw materials in parts by weight: 60 parts zirconium oxide, 15 parts aluminum oxide, 8 parts hydroxyapatite, 5 parts dimethylsilylated silica, 3 parts silica, 0.1 parts fluorapatite, 0.3 parts magnesium oxide, 3 parts thermosetting acrylic resin, 3 parts aluminum hydroxide gel, 1.5 parts silane coupling agent, 0.5 parts polyvinyl alcohol, and 0.5 parts sodium inositol hexaphosphate.

[0046] The preparation method of the above-mentioned enamel veneer restorative material includes the following steps:

[0047] S1: Zirconium oxide, aluminum oxide, hydroxyapatite, silicon dioxide, fluorapatite and magnesium oxide were premixed uniformly according to the mass fractions to obtain mixture A; polyvinyl alcohol and sodium inositol hexaphosphate were premixed uniformly to obtain mixture B; dimethyl silyl alkyl silicate was uniformly dispersed in thermosetting acrylic resin and vacuumed to obtain modified product C.

[0048] S2: Mix mixture A and mixture B evenly, then add aluminum hydroxide gel and silane coupling agent, mix evenly, then add modifier C, mix evenly to obtain the base material;

[0049] S3: The base material is molded and cold-pressed at a pressure of 8 MPa for 8 seconds at a temperature of 82°C. Then, isostatic pressing is performed at a pressure of 260 MPa for 50 seconds at a temperature of 120°C. After that, it is subjected to medium-temperature heat treatment at 600°C for 30 minutes, followed by high-temperature heat treatment at 1200°C for 60 minutes. After cooling, trimming, polishing, and cleaning, the formed dental veneer, i.e., enamel veneer restoration material, is obtained.

[0050] Example 3

[0051] A dental enamel veneer restorative material comprises the following raw materials in parts by weight: 62 parts zirconium oxide, 16 parts aluminum oxide, 9 parts hydroxyapatite, 6 parts dimethylsilylated silica, 4 parts silica, 0.2 parts fluorapatite, 0.35 parts magnesium oxide, 3.5 parts thermosetting acrylic resin, 3.5 parts aluminum hydroxide gel, 1.8 parts silane coupling agent, 0.8 parts polyvinyl alcohol, and 0.6 parts sodium inositol hexaphosphate.

[0052] The preparation method of the above-mentioned enamel veneer restorative material includes the following steps:

[0053] S1: Zirconium oxide, aluminum oxide, hydroxyapatite, silicon dioxide, fluorapatite and magnesium oxide were premixed uniformly according to the mass fractions to obtain mixture A; polyvinyl alcohol and sodium inositol hexaphosphate were premixed uniformly to obtain mixture B; dimethyl silyl alkyl silicate was uniformly dispersed in thermosetting acrylic resin and vacuumed to obtain modified product C.

[0054] S2: Mix mixture A and mixture B evenly, then add aluminum hydroxide gel and silane coupling agent, mix evenly, then add modifier C, mix evenly to obtain the base material;

[0055] S3: The base material is molded and cold-pressed at a pressure of 9 MPa for 9 seconds at a temperature of 84°C. Then, isostatic pressing is performed at a pressure of 265 MPa for 60 seconds at a temperature of 125°C. After that, it is subjected to medium-temperature heat treatment at 650°C for 40 minutes, followed by high-temperature heat treatment at 1250°C for 70 minutes. After cooling, trimming, polishing, and cleaning, the formed dental veneer, i.e., enamel veneer restoration material, is obtained.

[0056] Example 4

[0057] A dental enamel veneer restorative material comprises the following raw materials in parts by weight: 68 parts zirconium oxide, 19 parts alumina, 11 parts hydroxyapatite, 7 parts dimethylsilylated silica, 5 parts silica, 0.4 parts fluorapatite, 0.45 parts magnesium oxide, 5.5 parts thermosetting acrylic resin, 4.5 parts aluminum hydroxide gel, 2.5 parts silane coupling agent, 1.2 parts polyvinyl alcohol, and 1.4 parts sodium inositol hexaphosphate.

[0058] The preparation method of the above-mentioned enamel veneer restorative material includes the following steps:

[0059] S1: Zirconium oxide, aluminum oxide, hydroxyapatite, silicon dioxide, fluorapatite and magnesium oxide were premixed uniformly according to the mass fractions to obtain mixture A; polyvinyl alcohol and sodium inositol hexaphosphate were premixed uniformly to obtain mixture B; dimethyl silyl alkyl silicate was uniformly dispersed in thermosetting acrylic resin and vacuumed to obtain modified product C.

[0060] S2: Mix mixture A and mixture B evenly, then add aluminum hydroxide gel and silane coupling agent, mix evenly, then add modifier C, mix evenly to obtain the base material;

[0061] S3: The base material is molded and cold-pressed at a pressure of 14 MPa for 12 seconds at a temperature of 88°C. Then, isostatic pressing is performed at a pressure of 275 MPa for 70 seconds at a temperature of 140°C. After that, it is subjected to medium-temperature heat treatment at 750°C for 50 minutes, followed by high-temperature heat treatment at 1350°C for 80 minutes. After cooling, trimming, polishing, and cleaning, the formed dental veneer, i.e., enamel veneer restoration material, is obtained.

[0062] Example 5

[0063] A dental enamel veneer restorative material comprises the following raw materials in parts by weight: 70 parts zirconium oxide, 20 parts aluminum oxide, 12 parts hydroxyapatite, 8 parts dimethylsilylated silica, 6 parts silica, 0.5 parts fluorapatite, 0.5 parts magnesium oxide, 6 parts thermosetting acrylic resin, 5 parts aluminum hydroxide gel, 3 parts silane coupling agent, 1.5 parts polyvinyl alcohol, and 1.5 parts sodium inositol hexaphosphate.

[0064] The preparation method of the above-mentioned enamel veneer restorative material includes the following steps:

[0065] S1: Zirconium oxide, aluminum oxide, hydroxyapatite, silicon dioxide, fluorapatite and magnesium oxide were premixed uniformly according to the mass fractions to obtain mixture A; polyvinyl alcohol and sodium inositol hexaphosphate were premixed uniformly to obtain mixture B; dimethyl silyl alkyl silicate was uniformly dispersed in thermosetting acrylic resin and vacuumed to obtain modified product C.

[0066] S2: Mix mixture A and mixture B evenly, then add aluminum hydroxide gel and silane coupling agent, mix evenly, then add modifier C, mix evenly to obtain the base material;

[0067] S3: The base material is molded and cold-pressed at a pressure of 15 MPa for 15 seconds at a temperature of 90°C. Then, isostatic pressing is performed at a pressure of 280 MPa for 80 seconds at a temperature of 150°C. After that, it is subjected to medium-temperature heat treatment at 800°C for 60 minutes, followed by high-temperature heat treatment at 1400°C for 90 minutes. After cooling, trimming, polishing, and cleaning, the formed dental veneer, i.e., enamel veneer restoration material, is obtained.

[0068] In the above embodiments, the zirconium oxide, aluminum oxide, hydroxyapatite, silica, fluorapatite, and magnesium oxide all have nano-sized particles. The dimethyl silyl alkyl silica has a particle size range of 0.3 μm to 2 μm. The thermosetting acrylic resin is liquid, model HK87010, from Shanghai Kaiyin Chemical Co., Ltd. The aluminum hydroxide gel is a white viscous substance from Inner Mongolia Xinhong Biotechnology Co., Ltd. The silane coupling agent is model KH-560 from Dongguan Dinghai Plastics & Chemical Co., Ltd. The polyvinyl alcohol has a nano-sized particle size, model BP-26, from Changchun Chemical (Jiangsu) Co., Ltd. The sodium inositol hexaphosphate has a nano-sized particle size from Shandong Liyuan Biotechnology Co., Ltd.

[0069] Comparative Example 1

[0070] The raw materials contain 5 parts of hydroxyapatite and 70 parts of zirconium oxide; other methods and parameters are the same as in Example 1.

[0071] Comparative Example 2

[0072] In this case, no dimethylsilyl silica was added; the content of dimethylsilyl silica was replaced by zirconium oxide. Other methods and parameters were the same as in Example 1.

[0073] Comparative Example 3

[0074] In the raw materials, the amount of dimethylsilyl alkyl silica added is 2.5 parts, and the amount of zirconium oxide added is 69 parts; other methods and parameters are the same as in Example 1.

[0075] Comparative Example 4

[0076] In the raw materials, the amount of thermosetting acrylic resin added is 1.5 parts, and the amount of zirconium oxide added is 68 parts; other methods and parameters are the same as in Example 1.

[0077] Comparative Example 5

[0078] In the raw materials, the amount of dimethylsilyl alkyl silica added is 2.5 parts, the amount of thermosetting acrylic resin added is 1.5 parts, and the amount of zirconium oxide added is 72 parts; other methods and parameters are the same as in Example 1.

[0079] Comparative Example 6

[0080] The particle size range of the dimethylsilyl alkyl silica in the raw materials is 0.05 μm to 0.5 μm; other methods and parameters are the same as in Example 1.

[0081] Comparative Example 7

[0082] In this case, aluminum hydroxide gel was not added; the aluminum hydroxide gel content was replaced by zirconium oxide. Other methods and parameters were the same as in Example 1.

[0083] Comparative Example 8

[0084] Sodium inositol hexaphosphate was not added to the raw materials; its content was replaced by zirconium oxide. Other methods and parameters were the same as in Example 1.

[0085] Comparative Example 9

[0086] In the preparation method, dimethylsilylated silica is involved in the preparation of mixture A, that is, dimethylsilylated silica is not mixed with thermosetting acrylic resin for modification. In S2, the modified product C is directly made of thermosetting acrylic resin; other methods and parameters are the same as in Example 1.

[0087] Comparative Example 10

[0088] In the preparation method, the cold pressing temperature is 25℃ (room temperature), and the isostatic pressing temperature is 25℃ (room temperature); other methods and parameters are the same as in Example 1.

[0089] The performance of the dental veneers (enamel veneer restoration materials) prepared in the above embodiments and comparative examples was tested.

[0090] I. Performance Testing

[0091] Flexural strength was tested according to GB30367 method; Vickers hardness was tested using a Vickers hardness tester according to GB / T4340 method; fracture toughness was tested using the single-sided V-groove beam method; the coefficient of thermal expansion was measured using a thermal expansion meter at a simulated human body temperature of 37℃; aging performance was tested under the condition of aging at 135℃ for 5 hours, and the monoclinic phase content was measured using XRD. The test results are shown in Table 1 below.

[0092] Table 1 Performance Test Results

[0093]

[0094]

[0095] The results above show that the ceramic dental veneers of Examples 1 to 5 exhibit good performance, maintaining high flexural strength, Vickers hardness, and fracture toughness, with a reduced coefficient of thermal expansion and good anti-aging properties. Comparative Example 1 shows that adding an appropriate amount of hydroxyapatite in combination with other components can improve the toughness of the ceramic dental veneers, while reducing the hydroxyapatite content significantly reduces fracture toughness. Comparative Examples 2 and 3 show that appropriately adding dimethylsilyl silica can effectively reduce the coefficient of thermal expansion of the ceramic dental veneers, and in combination with other components, it can improve the anti-aging properties of the ceramic dental veneers. Comparative Example 4 shows that adding an appropriate amount of thermosetting acrylic resin can enhance the bonding tightness of the components, increase density, thereby improving flexural strength, Vickers hardness, fracture toughness, reducing the coefficient of thermal expansion, and further enhancing anti-aging properties. The results of Comparative Example 5 show that the combined use of appropriate amounts of dimethyl silyl silica and thermosetting acrylic resin can significantly reduce the coefficient of thermal expansion and anti-aging properties of ceramic dental veneers. Furthermore, the interaction between dimethyl silyl silica and thermosetting acrylic resin can regulate and balance the flexural strength, Vickers hardness, and fracture toughness of the ceramic dental veneers. Reducing the amount of both dimethyl silyl silica and thermosetting acrylic resin does not achieve good anti-aging and expansion reduction effects. The results of Comparative Example 6 show that reducing the particle size of dimethyl silyl silica has little impact on physical properties. The results of Comparative Example 7 show that aluminum hydroxide gel can increase the compaction density of the material, participates in the reaction during sintering, and thus helps to increase the sintering density of the ceramic dental veneers, improve flexural strength, Vickers hardness, and fracture toughness, and reduce the coefficient of thermal expansion. The results of Comparative Example 8 show that sodium inositol hexaphosphate, after sintering, can significantly improve the anti-aging properties of ceramic dental veneers. The results of Comparative Example 9 show that not mixing dimethylsilylated silica with thermosetting acrylic resin will affect the performance of dimethylsilylated silica, resulting in a decrease in flexural strength, Vickers hardness, and fracture toughness, as well as an increase in the coefficient of thermal expansion and poor aging resistance. The results of Comparative Example 10 show that lowering the temperature of cold pressing and isostatic pressing will affect the compaction and bonding of the base material, as well as the quality of medium-temperature and high-temperature heat treatments, thus leading to a decline in performance.

[0096] II. In vitro adhesion test

[0097] The thickness of the dental veneer sample was 0.10 mm. The tooth model used was a discarded human tooth removed from the body in a hospital. The veneer was applied using conventional methods: the discarded tooth was ground and acid-etched to remove part of the enamel, reducing the thickness to 0.14 mm. The veneer was then bonded to the treated tooth using light-cured resin. Testing was conducted 24 hours after bonding: the tooth was hammered until it was pulverized, the veneer was removed, cleaned of dust, rinsed with water, and dried. The adhesion between the veneer and the tooth components was observed. A commercially available ceramic veneer (alumina ceramic dental veneer) was used as a comparative experiment. Three parallel samples were prepared for each method, and the average value was taken. The test results are shown in Table 2 below.

[0098] Table 2 Adhesion test results

[0099] Sample Adhesion rating Sample Adhesion rating Example 1 1 Comparative Example 1 2 Example 2 1 Comparative Example 2 4 Example 3 1 Comparative Example 3 3 Example 4 1 Comparative Example 4 2 Example 5 1 Comparative Example 5 4 Commercially available ceramic tiles 4 Comparative Example 6 2 Comparative Example 7 1 Comparative Example 8 1 Comparative Example 9 2 Comparative Example 10 1

[0100] Evaluation Grades: 1 - The area of ​​the veneer bonded to the tooth surface is greater than 90% and less than or equal to 100%; 2 - The area of ​​the veneer bonded to the tooth surface is greater than 80% and less than or equal to 90%; 3 - The area of ​​the veneer bonded to the tooth surface is greater than 70% and less than or equal to 80%; 4 - The area of ​​the veneer bonded to the tooth surface is greater than 60% and less than or equal to 70%; 5 - The area of ​​the veneer bonded to the tooth surface is greater than 50% and less than or equal to 60%; 6 - The area of ​​the veneer bonded to the tooth surface is greater than 40% and less than or equal to 50%.

[0101] The results above show that the dental veneers prepared in Examples 1 to 5 have excellent biocompatibility and adhesion, effectively reducing the risk of chipping and detachment. They also reduce the thickness removed during tooth grinding, achieving good adhesion even with a thickness of only 0.14 mm. The comparative results show that hydroxyapatite, dimethylsilylated silica, and thermosetting acrylic resin all significantly improve the adhesion of ceramic dental veneers. The particle size of dimethylsilylated silica also affects adhesion; a particle size range of 0.3 μm to 2 μm improves adhesion. Mixing and modifying dimethylsilylated silica with thermosetting acrylic resin, followed by surface modification and degassing, further enhances adhesion.

[0102] III. Human Trial Evaluation

[0103] Forty-three subjects with dental injuries in the anterior region were selected. A total of 150 teeth in the anterior region of these 43 subjects required veneers. Ninety teeth were divided into 15 groups of 10 teeth each. Each group was fitted with a veneer prepared according to the specific embodiment and comparative example. The thickness and shape of the veneer were determined based on the specific tooth shape. After the veneers were applied, the subjects continued their normal lives, and the usage data was collected. The usage evaluation results are shown in Table 3 below.

[0104] Table 3 Trial Evaluation Results

[0105]

[0106] The results above show that the ceramic dental veneers prepared in Examples 1 to 5 have good biocompatibility, good adhesion, and are not prone to chipping or falling off, effectively improving the user experience of ceramic dental veneers and extending their service life.

Claims

1. A dental enamel veneer restorative material, characterized in that, The enamel veneer restorative material comprises the following raw materials in parts by weight: 60-70 parts zirconium oxide, 15-20 parts alumina, 8-12 parts hydroxyapatite, 5-8 parts dimethyl silylated silica, 3-6 parts silica, 0.1-0.5 parts fluorapatite, 0.3-0.5 parts magnesium oxide, 3-6 parts thermosetting acrylic resin, 3-5 parts aluminum hydroxide gel, 1.5-3 parts silane coupling agent, 0.5-1.5 parts polyvinyl alcohol, and 0.5-1.5 parts sodium inositol hexaphosphate; The particle size range of the dimethylsilyl alkyl silica is 0.3 μm to 2 μm; Zirconia, alumina, hydroxyapatite, silica, fluorapatite, and magnesium oxide are premixed uniformly to obtain mixture A; polyvinyl alcohol and sodium inositol hexaphosphate are premixed uniformly to obtain mixture B; dimethyl silyl alkyl silicate is uniformly dispersed in thermosetting acrylic resin, and vacuum degassing is performed to obtain modified material C; mixture A and mixture B are mixed uniformly, then aluminum hydroxide gel and silane coupling agent are added and mixed uniformly, then modified material C is added and mixed uniformly to obtain a base material; the base material is molded and subjected to cold pressing at 80℃~90℃, isostatic pressing at 120℃~150℃, medium-temperature heat treatment, and high-temperature heat treatment in sequence to obtain a shaped enamel veneer restoration material.

2. The enamel veneer restorative material according to claim 1, characterized in that, The zirconium oxide, aluminum oxide, hydroxyapatite, silicon dioxide, fluorapatite, and magnesium oxide are all nanoscale in size.

3. The enamel veneer restorative material according to claim 1, characterized in that, The thermosetting acrylic resin is liquid and is designated HK87010; the silane coupling agent is designated KH-560; and the polyvinyl alcohol and sodium inositol hexaphosphate are both nano-sized.

4. A method for preparing a dental enamel veneer restorative material, used to prepare the dental enamel veneer restorative material according to claim 1, characterized in that, The preparation method includes the following steps: S1: Zirconium oxide, aluminum oxide, hydroxyapatite, silicon dioxide, fluorapatite and magnesium oxide were premixed uniformly according to the mass fractions to obtain mixture A; polyvinyl alcohol and sodium inositol hexaphosphate were premixed uniformly to obtain mixture B; dimethyl silyl alkyl silicate was uniformly dispersed in thermosetting acrylic resin and vacuumed to obtain modified product C. S2: Mix mixture A and mixture B evenly, then add aluminum hydroxide gel and silane coupling agent, mix evenly, then add modifier C, mix evenly to obtain the base material; S3: The base material is molded and then subjected to cold pressing, isostatic pressing, medium-temperature heat treatment, and high-temperature heat treatment in sequence to obtain the formed dental veneer, i.e., enamel veneer restoration material.

5. The method for preparing a dental enamel veneer restorative material according to claim 4, characterized in that, In S3, the cold pressing pressure is 8MPa to 15MPa, the cold pressing time is 8s to 15s, and the cold pressing temperature is 80℃ to 90℃.

6. The method for preparing a dental enamel veneer restorative material according to claim 4, characterized in that, In S3, the isostatic pressure is 260MPa~280MPa, the isostatic pressure time is 50s~80s, and the isostatic pressure temperature is 120℃~150℃.

7. The method for preparing a dental enamel veneer restorative material according to claim 4, characterized in that, In S3, the temperature of the medium-temperature heat treatment is 600℃~800℃, and the time of the medium-temperature heat treatment is 30min~60min.

8. The method for preparing a dental enamel veneer restorative material according to claim 4, characterized in that, In S3, the temperature of the high-temperature heat treatment is 1200℃~1400℃, and the time of the high-temperature heat treatment is 60min~90min.

Images