Dental composite resin and method for preparing the same

Abstract

The application provides a preparation method of a dental composite resin, comprising the following steps: (1) mixing spherical silica fillers with an aqueous hydrofluoric acid solution to obtain a mixed solution, continuously stirring the mixed solution and then standing and precipitating, washing and drying the obtained precipitate to obtain etched silica fillers; (2) treating the etched silica fillers with a silane coupling agent to obtain modified silica fillers; and (3) adding the modified silica fillers into a resin matrix to obtain the dental composite resin. The spherical silica fillers are modified by using a surface etching technology, so that the smooth spherical silica fillers form uneven surfaces, form firm micro-mechanical inlaying between the silica fillers and the resin matrix, increase the surface free energy, improve the silane coupling agent grafting rate of the silica surface, improve the combination of the fillers and the resin matrix by promoting physical inlaying and chemical crosslinking, and increase the maximum addition amount of the silica.

Description

Technical Field

[0001] This invention relates to the field of surface treatment technology for dental composite resin fillers, and in particular to a novel method for surface treatment of spherical silica fillers to improve the mechanical properties of composite resins. Background Technology

[0002] Dental caries is one of the three major diseases prioritized for prevention and control by the World Health Organization. Clinically, fillings are the preferred treatment for dental caries, and composite resin, as one of the most common dental filling materials, is widely used in clinical practice due to its ease of application and aesthetic appeal. During chewing, the filling material bears the brunt of wear from food and opposing teeth under the combined force, requiring sufficient strength and wear resistance in its mechanical properties to withstand the complex oral environment for a long time. Although there are many composite resin products on the market, their flexural strength, compressive strength, and wear resistance are still insufficient, especially in posterior tooth fillings. According to recent clinical observations of composite resin fillings, insufficient mechanical properties of composite resin materials remain one of the main factors leading to clinical failure.

[0003] The basic components of composite resins mainly include resin matrix, inorganic fillers, initiation system, and pigments. Among them, inorganic fillers, as the dispersed phase and reinforcement of other components, play a decisive role in the mechanical properties of composite resins.

[0004] After more than 50 years of development, current composite resin fillers exhibit multi-scale characteristics: the coexistence of micron, submicron, and nano-scale sizes allows for a continuous increase in the filler's mass fraction in composite resins, providing higher flexural strength and abrasion resistance. Because composite resins must meet mechanical performance requirements while also considering transparency and color, the most common filler composition used in current market composite resin products is granular silica-based filler as the main component.

[0005] Silica fillers, as inorganic compounds, cannot directly form chemical bonds with resin matrices. Surface treatment with coupling agents is necessary to achieve a tight bond between the filler and the resin matrix. This is particularly important in multi-component filler compositions with tiered structures, where the presence of numerous nanoparticles increases the interfacial area between the organic and inorganic phases. In this case, enhancing the bonding between the inorganic filler and the organic resin matrix becomes crucial. Studies have found that adding more than 10 wt% nano-sized silica fillers to composite resins leads to nanoclusters, preventing the filler from being uniformly dispersed in the resin matrix and forming a good bond. This not only fails to provide reinforcement but can even reduce flexural strength. Furthermore, due to the small particle size and high surface energy of nanofillers, the resin matrix is ​​difficult to wet and disperse, significantly limiting their addition amount in composite resins. Summary of the Invention

[0006] To address the issues of dispersion and bonding of spherical silica fillers, especially nano-sized fillers, in dental composite resins, and to explore how to increase the amount of spherical silica particles added, this invention provides a dental composite resin and its preparation method.

[0007] This invention is achieved through the following technical solution:

[0008] A method for preparing a dental composite resin includes the following steps:

[0009] (1) Mix spherical silica filler with hydrofluoric acid aqueous solution to obtain a mixture. After stirring the mixture continuously, let it stand to precipitate. Wash and dry the precipitate to obtain etched silica filler.

[0010] (2) The etched silica filler was treated with a silane coupling agent to obtain a modified silica filler;

[0011] (3) Modified silica filler is added to the resin matrix to obtain dental composite resin.

[0012] Preferably, in step (1), the spherical silica filler has a size of one or more of the following: nanoscale, submicron scale, and micron scale.

[0013] Furthermore, in step (1), the spherical silica filler is mixed with the hydrofluoric acid aqueous solution. Specifically, micron-sized or submicron-sized spherical silica filler is added to the hydrofluoric acid aqueous solution, or hydrofluoric acid aqueous solution is added dropwise to an aqueous suspension or ethanol suspension containing nano-sized spherical silica filler.

[0014] Preferably, in step (1), the concentration of hydrofluoric acid in the mixture is 1%-5%, and the stirring time is 1-3h.

[0015] Preferably, in step (2), the silane coupling agent is γ-methacryloxypropyltrimethoxysilane.

[0016] Further, step (2) specifically involves: adding n-propylamine, silane coupling agent and etched silica filler to cyclohexane, stirring at room temperature, and then heating and stirring to react; or, adding silane coupling agent and etched silica filler to an ethanol aqueous solution with a pH of 3-4, and stirring at room temperature.

[0017] Preferably, in step (3), the amount of modified silica filler added is 40%-75% based on the total mass of the dental composite resin.

[0018] Preferably, step (3) specifically involves mixing the resin matrix, diluent, photoinitiator, photosensitizing promoter, polymerization inhibitor, and modified silica filler uniformly under light-protected conditions by mechanical mixing or reduced-pressure solvent evaporation.

[0019] Preferably, in step (3), the resin matrix is ​​bisphenol A glycerol dimethacrylate, ethoxybisphenol A dimethacrylate, or urethane dimethacrylate.

[0020] The dental composite resin obtained by the preparation method described above.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This invention employs a surface etching technique to modify spherical silica fillers. Through chemical etching, an uneven structure is formed on the smooth surface of the spherical silica filler, enabling a strong micromechanical intercalation between the filler and the resin matrix and increasing surface free energy. Simultaneously, the hydrofluoric acid surface etching technique increases the silanol content on the silica surface, which facilitates the grafting rate of silane coupling agents on the filler surface. Adding silanized, surface-etched spherical silica fillers to dental resin matrices enhances the bonding between the filler and the resin matrix by promoting both physical intercalation and chemical cross-linking of the silanized silica / resin matrix. Furthermore, the increased grafting rate of silane coupling agents on the filler surface further increases the miscibility of silica and resin, improves silica dispersion, and increases the maximum silica addition amount. This, in turn, improves the mechanical properties of the composite resin, such as flexural strength, elastic modulus, and hardness, while reducing polymerization shrinkage. This invention fills a gap in surface treatment technology for spherical silica fillers, significantly improves the mechanical properties of composite resins, and has promising clinical application prospects.

[0023] Furthermore, for micron- and submicron-sized spherical silica fillers, surface etching can be achieved by adding them to an aqueous hydrofluoric acid solution and stirring the reaction. For nano-sized fillers, they are first dispersed in an aqueous or ethanol solution by ultrasonic dispersion or ball milling before being added to an aqueous hydrofluoric acid solution for etching to avoid nano-clusters and achieve uniform etching.

[0024] Furthermore, since γ-methacryloxypropyltrimethoxysilane hydrolyzes very slowly in water, acid activation, n-propylamine catalysis, or heat treatment are required to accelerate the silanization of silica. Both currently available silanization methods can achieve the purpose of silanizing fillers; however, for nanoscale fillers, n-propylamine catalysis can achieve better silanization results. Attached Figure Description

[0025] Figure 1 SEM images of micron-sized spherical silica particles before (A) and after (B) hydrofluoric acid etching;

[0026] Figure 2SEM images of submicron-sized spherical silica particles before (A) and after (B) hydrofluoric acid etching;

[0027] Figure 3 SEM images of nanoscale spherical silica particles before (A) and after (B) hydrofluoric acid etching;

[0028] Figure 4 Infrared spectra of untreated nanoscale silica filler and hydrofluoric acid-etched nanoscale silica filler.

[0029] Figure 5 Infrared spectra of untreated micron-sized silica filler and hydrofluoric acid-etched micron-sized silica filler (a) and infrared spectra of untreated micron-sized silica filler and hydrofluoric acid-etched micron-sized silica filler before and after silanization (b).

[0030] Figure 6 The three-point bending strength of micron-sized spherical silica-based composite resin. Detailed Implementation

[0031] To further understand the present invention, the present invention will be described below with reference to embodiments. These descriptions are only for further explaining the features and advantages of the present invention and are not intended to limit the claims of the present invention.

[0032] The method for preparing the dental composite resin of the present invention includes the following steps:

[0033] (1) Chemical etching method to etch the surface of nano-, submicron or micron-sized spherical silica fillers

[0034] Nanoscale, submicron-scale, or micron-scale spherical silica fillers, or their aqueous or ethanol suspensions, are mixed with an aqueous solution of hydrofluoric acid of a certain concentration to obtain a mixture. After continuous stirring, the mixture is allowed to settle and precipitate. The precipitate is washed with distilled water, and the resulting powder is dried in air to constant weight and then ground to obtain hydrofluoric acid-etched silica filler. The concentration of hydrofluoric acid in the mixture is 1%-5%, and the stirring time is 1-3 hours.

[0035] (2) Treating the silica filler etched by hydrofluoric acid with a silane coupling agent

[0036] Prepare an acidic ethanol / aqueous solution (pH 3-4) or an alkaline cyclohexane solution of the silane coupling agent at a certain concentration. Immerse the above-mentioned hydrofluoric acid-etched silica filler at room temperature for a certain period of time, or heat to accelerate the polymerization reaction, followed by ultrasonic cleaning with ethanol, centrifugation, and drying. Repeat this cleaning process to remove unreacted silane coupling agent monomers, thereby obtaining the modified silica filler. The preferred silane coupling agent is KH570 (γ-methacryloyloxypropyltrimethoxysilane).

[0037] (3) Addition of modified silica filler to dental composite resin

[0038] In a resin system containing a resin matrix, modified silica filler is added via mechanical mixing or vacuum solvent evaporation to prepare various types of dental composite resins with enhanced mechanical properties. The resin system comprises a resin matrix, diluent, photoinitiator, photosensitizer, and polymerization inhibitor. Based on the total mass of the dental composite resin, the content of each substance is as follows: 40%–75% modified silica filler, 24–59% resin matrix, 0.05%–3% photoinitiator, 0.05%–3% photosensitizer, and 0.001%–0.05% polymerization inhibitor. The resin matrix is ​​bisphenol A glycerol dimethacrylate (Bis-GMA), ethoxybisphenol A dimethacrylate (Bis-EMA), or urethane dimethacrylate (UDMA).

[0039] This invention describes the chemical characterization and morphological observation of nanoscale, submicron, or micron-scale spherical silica fillers treated by chemical etching, verifying changes in surface morphology and the resulting alterations in silanol groups. The spherical silica fillers were surface-activated using a KH570-containing treatment agent, and the changes in silanol groups, Si-O-Si bonds, C=O bonds, and C=C bonds after treatment were detected through chemical characterization. Nanoscale, submicron, or micron-scale spherical silica fillers, or multi-scale fillers, treated with KH570 and etched by hydrofluoric acid, were added to a resin matrix to synthesize a reinforced composite resin. The effect of chemical etching on the mechanical properties of the composite resin was evaluated using the corresponding unetched filler group as a control.

[0040] The specific implementation method is as follows.

[0041] Example 1:

[0042] Micron-sized spherical silica fillers (particle size 3-12 μm, average particle size 8 μm) were added to a 5% hydrofluoric acid aqueous solution. After stirring continuously at room temperature for 2 hours, the mixture was allowed to stand and precipitate. The precipitate was washed with distilled water, and the resulting powder was dried in air to constant weight. The powder was then ground to obtain micron-sized spherical silica fillers etched by hydrofluoric acid.

[0043] Example 2:

[0044] A 5% hydrofluoric acid aqueous solution was added dropwise to an aqueous suspension containing micron-sized spherical silica filler (particle size 3-12 μm, average particle size 8 μm) to make the hydrofluoric acid content in the water 1%. The mixture was stirred continuously at room temperature for 3 hours and then allowed to stand to precipitate. The precipitate was washed with distilled water, and the resulting powder was dried in air to constant weight and ground to obtain micron-sized spherical silica filler etched by hydrofluoric acid.

[0045] Comparative Example 1:

[0046] Micron-sized spherical silica fillers (particle size 3-12 μm, average particle size 8 μm) were added to a 10% (w / w) hydrofluoric acid aqueous solution. After stirring continuously at room temperature for 2 hours, the mixture was allowed to settle and precipitate. The precipitate was washed with distilled water, and the resulting powder was air-dried to constant weight and then ground. SEM observation revealed that the internal structure of many spherical fillers was damaged, and the surface was severely etched. This indicates that excessively high hydrofluoric acid concentrations can destroy the micron-sized spherical silica structure, making it impossible to obtain solid silica with micro-etched surfaces.

[0047] Comparative Example 2:

[0048] A 5% (w / w) aqueous solution of hydrofluoric acid was added dropwise to an aqueous suspension containing micron-sized spherical silica fillers (average particle size 3-12 μm), bringing the hydrofluoric acid concentration in the water to 1%. The mixture was stirred continuously at room temperature for 12 hours, then allowed to settle. The precipitate was washed with distilled water, and the resulting powder was air-dried to constant weight and then ground. SEM observation revealed a significant reduction in the particle size of the spherical fillers and a smooth surface. This indicates that prolonged etching with low-concentration hydrofluoric acid reduces the surface roughness and particle size of the micron-sized spherical silica, resulting in a smooth surface.

[0049] Example 3:

[0050] Submicron-sized spherical silica filler (average particle size 400 nm) was added to a 5% hydrofluoric acid aqueous solution. After stirring continuously at room temperature for 1 hour, the mixture was allowed to stand and precipitate. The precipitate was washed with distilled water, and the resulting powder was dried in air to constant weight. The powder was then ground to obtain hydrofluoric acid-etched submicron-sized spherical silica filler.

[0051] Comparative Example 3:

[0052] Submicron-sized spherical silica fillers (average particle size 400 nm) were added to a 5% (w / w) hydrofluoric acid aqueous solution. After stirring continuously at room temperature for 3 hours, the mixture was allowed to settle and precipitate. The precipitate was washed with distilled water, and the resulting powder was air-dried to constant weight and then ground. SEM observation revealed severe surface etching on many of the spherical fillers. This indicates that prolonged hydrofluoric acid etching destroys the spherical silica structure, making it impossible to obtain solid silica with micro-etched surfaces.

[0053] Example 4:

[0054] Submicron-sized spherical silica filler (average particle size 400 nm) was added to a 2.5% hydrofluoric acid aqueous solution. After stirring continuously at room temperature for 2 hours, the mixture was allowed to stand and precipitate. The precipitate was washed with distilled water, and the resulting powder was dried in air to constant weight. The powder was then ground to obtain hydrofluoric acid-etched submicron-sized spherical silica filler.

[0055] Example 5:

[0056] Nanoscale spherical silica filler (average particle size 30 nm) was added to a 5% (w / w) hydrofluoric acid aqueous solution. After stirring continuously at room temperature for 1 hour, the mixture was allowed to settle and precipitate. The precipitate was washed with distilled water, and the resulting powder was air-dried to constant weight and then ground to obtain hydrofluoric acid-etched nanoscale spherical silica filler. Unetched nanoscale spherical silica was used as a control group. The effect of hydrofluoric acid treatment on nanoscale silica was detected by infrared spectroscopy. The results are as follows: Figure 4 As shown, the 3438 cm³ of nano-sized silica filler treated with hydrofluoric acid... -1 The -OH peak at that location increases.

[0057] The surface morphology of the micron, submicron, and nano-sized spherical silica particles etched with 5% hydrofluoric acid in Examples 1, 3, and 5 was observed by SEM, and the results are as follows: Figure 1-3 As shown. Figure 1 Medium-micron silica particles (A) are spherical with a smooth, non-porous surface and a small amount of impurities. After being etched with hydrofluoric acid (B), the surface becomes rough, forming a dense, uneven structure. Figure 2 Before etching, the surface of medium-micron silica (A) is smooth, while after etching (B) the surface is rough, forming an uneven surface structure. Figure 3 Before etching of medium- and nano-sized silica, (A) the nanoparticles showed severe clustering. After etching, (B) the nanoparticles melted and formed a grape branch-like structure, reducing the clustering phenomenon.

[0058] Example 6:

[0059] The micron-sized spherical silica particles etched by hydrofluoric acid in Example 1 were subjected to silanization treatment. Propylamine, KH570, and spherical silica were added to cyclohexane at a mass ratio of 1:5:50, stirred at room temperature for 30 minutes, then stirred at 65°C for 30 minutes, ultrasonically cleaned, centrifuged, and dried. Unetched silica and silanized unetched silica were used as control groups. The effect of hydrofluoric acid treatment on the silanization of silica was detected by infrared spectroscopy. The results are as follows: Figure 5 As shown, the 1112 cm³ micron-sized silica filler after hydrofluoric acid treatment -1 The stretching vibration peaks of the Si-O-Si bonds at this location are sharper. The etch group after silanization is located at 1720 cm⁻¹. -1 and 1637cm -1 The vibrational peaks of nearby C=O and C=C bonds are stronger than those of the silanized unetched group, since they all originate from the carbonyl and vinyl groups of KH570, indicating that hydrofluoric acid etching can increase the coupling between KH570 and spherical silica.

[0060] Example 7:

[0061] The micron-sized spherical silica particles etched by hydrofluoric acid in Example 1 were subjected to silanization treatment. KH570 was added to an aqueous solution of 70 wt% ethanol and 30 wt% distilled water (pH 3–4) for pre-hydrolysis for 1 hour. The spherical silica particles were then added to the KH570 treatment agent at a mass ratio of 10:1 to KH570. The mixture was stirred at room temperature for 1 hour, ultrasonically cleaned, centrifuged, and dried.

[0062] Example 8:

[0063] The submicron-sized spherical silica particles etched by hydrofluoric acid in Example 3 were subjected to silanization treatment. Propylamine, KH570, and spherical silica were added to cyclohexane at a mass ratio of 1:5:50, stirred at room temperature for 30 minutes, then stirred at 65°C for 30 minutes, ultrasonically cleaned, centrifuged, and dried.

[0064] Example 9:

[0065] The nanoscale spherical silica particles etched by hydrofluoric acid in Example 5 were subjected to silanization treatment. Propylamine, KH570, and spherical silica were added to cyclohexane at a mass ratio of 1:5:50, stirred at room temperature for 30 minutes, then stirred at 65°C for 30 minutes, ultrasonically cleaned, centrifuged, and dried.

[0066] Example 10:

[0067] The resin matrix Bis-GMA (bisphenol A glycerol dimethacrylate) and diluent TEGDMA (triethylene glycol dimethacrylate) were mixed evenly at a mass ratio of 7:3. Then, 0.5 wt% of photoinitiator CQ (camphorquinone), 0.5 wt% of photosensitizer EDMAB (ethyl 4-dimethylaminobenzoate), and 0.05% of polymerization inhibitor p-methoxyphenol were added. The mixture was kept in the dark and thoroughly stirred. Then, the micron-sized spherical silica filler treated with KH570 and etched by hydrofluoric acid (as described in Example 6) was added and mechanically stirred until homogeneous (total filler mass fractions were 40%, 50%, 60%, and 70%, respectively). The mixture was stored in the dark. A composite resin with the same formulation containing KH570-treated, un-etched silica filler was used as a control. The three-point bending strength test results are as follows: Figure 6 As shown, the filler group with added hydrofluoric acid etching exhibits higher flexural strength.

[0068] Example 11:

[0069] The resin matrix Bis-GMA (bisphenol A glycerol dimethacrylate) and the diluent TEGDMA (triethylene glycol dimethacrylate) were mixed evenly at a mass ratio of 7:3. Then, 0.5 wt% of photoinitiator CQ (camphorquinone), 0.5 wt% of photosensitizer EDMAB (ethyl 4-dimethylaminobenzoate), and 0.05% of polymerization inhibitor p-methoxyphenol were added. The mixture was kept in the dark and thoroughly stirred. Then, the micron-sized spherical silica filler etched with hydrofluoric acid after KH570 treatment in Example 6 was added and mechanically stirred until evenly mixed (total filler mass fraction: 75%). The mixture was then stored in the dark.

[0070] Example 12:

[0071] The resin matrix Bis-EMA (ethoxybisphenol A dimethacrylate) and the diluent TEGDMA (triethylene glycol dimethacrylate) were mixed evenly at a mass ratio of 7:3. Then, 0.5 wt% of photoinitiator CQ (camphorquinone), 0.5 wt% of photosensitizer EDMAB (ethyl 4-dimethylaminobenzoate), and 0.05% of polymerization inhibitor p-methoxyphenol were added. The mixture was kept in the dark and thoroughly stirred. Then, the micron-sized spherical silica filler etched with hydrofluoric acid after KH570 treatment in Example 6 was added and mechanically stirred until evenly mixed (total filler mass fraction was 70%). The mixture was then stored in the dark.

[0072] Example 13:

[0073] The resin matrix UDMA (urethane dimethacrylate) and diluent TEGDMA (triethylene glycol dimethacrylate) were mixed evenly at a mass ratio of 7:3. Then, 0.5 wt% of photoinitiator CQ (camphorquinone), 0.5 wt% of photosensitizer EDMAB (ethyl 4-dimethylaminobenzoate), and 0.05% of polymerization inhibitor p-methoxyphenol were added. The mixture was kept in the dark and thoroughly stirred. Then, the micron-sized spherical silica filler etched with hydrofluoric acid after KH570 treatment in Example 6 was added and mechanically stirred until evenly mixed (total filler mass fraction: 70%). The mixture was then stored in the dark.

[0074] Example 14:

[0075] The resin matrix Bis-GMA and diluent TEGDMA were mixed evenly at a mass ratio of 7:3. Then, 0.5 wt% photoinitiator CQ, 0.5 wt% photosensitizer EDMAB, and 0.05% polymerization inhibitor p-methoxyphenol were added. The mixture was kept in the dark and thoroughly stirred. Then, the submicron-sized spherical silica filler treated with KH570 and etched by hydrofluoric acid (as in Example 8) was added and mechanically stirred until homogeneous. The filler addition was maximized without affecting the clinical operability of the resin, and the mixture was stored in the dark. A control group consisting of un-etched submicron-sized silica filler treated with KH570 and having the highest addition amount was used. The results showed that the filler addition amount in the etched group was 73.5%, while the maximum addition amount in the control group was 62.5%.

[0076] Example 15:

[0077] The resin matrix Bis-GMA and diluent TEGDMA were mixed evenly at a mass ratio of 7:3. 0.5 wt% photoinitiator CQ, 0.5 wt% photosensitizing promoter EDMAB, and 0.05% polymerization inhibitor p-methoxyphenol were added. After thorough mixing in the dark, the nanoscale spherical silica filler etched by hydrofluoric acid after KH570 treatment in Example 9 was added and mixed evenly by vacuum solvent evaporation. The mixture was then stored in the dark.

[0078] Example 16:

[0079] The resin matrix Bis-GMA and diluent TEGDMA were mixed evenly at a mass ratio of 7:3. Then, 0.5 wt% of photoinitiator CQ, 0.5 wt% of photosensitizing promoter EDMAB, and 0.05% of polymerization inhibitor p-methoxyphenol were added. The mixture was kept in the dark and stirred thoroughly. Then, 60 wt% of the micron-sized spherical silica filler from Example 6 and 10 wt% of the nano-sized spherical silica filler from Example 9 were added. The mixture was then mixed evenly by vacuum solvent evaporation and stored in the dark.

[0080] The above description is a further detailed explanation of the present invention in conjunction with specific preferred embodiments. It should not be considered that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the patent protection scope defined by the claims submitted by the present invention.

Claims

1. A method for preparing a dental composite resin, characterized in that, Includes the following steps: (1) A spherical silica filler is mixed with an aqueous hydrofluoric acid solution to obtain a mixture. The mixture is stirred continuously and then allowed to stand to precipitate. The precipitate is washed and dried to obtain an etched silica filler. The mass concentration of hydrofluoric acid in the mixture is 1%-5%, and the stirring time is 1-2 hours. The size of the spherical silica filler is one or more of the following: nanoscale, submicron scale, and micron scale. (2) The etched silica filler was treated with a silane coupling agent to obtain a modified silica filler; (3) The resin matrix, diluent, photoinitiator, photosensitizer, polymerization inhibitor and modified silica filler are mixed evenly under light-protected conditions by mechanical mixing or reduced pressure solvent evaporation to obtain dental composite resin. In step (1), the spherical silica filler is mixed with hydrofluoric acid aqueous solution. Specifically, micron-sized or submicron-sized spherical silica filler is added to hydrofluoric acid aqueous solution, or hydrofluoric acid aqueous solution is added dropwise to an aqueous suspension or ethanol suspension containing nano-sized spherical silica filler.

2. The method for preparing dental composite resin according to claim 1, characterized in that, In step (2), the silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane.

3. The method for preparing dental composite resin according to claim 2, characterized in that, Step (2) specifically involves adding n-propylamine, silane coupling agent, and etched silica filler to cyclohexane, stirring at room temperature, and then heating and stirring to react; or adding silane coupling agent and etched silica filler to an ethanol aqueous solution with a pH of 3-4, and stirring at room temperature.

4. The method for preparing dental composite resin according to claim 1, characterized in that, In step (3), the amount of modified silica filler added is 40%-75% based on the total mass of dental composite resin.

5. The method for preparing dental composite resin according to claim 1, characterized in that, In step (3), the resin matrix is ​​bisphenol A glycerol dimethacrylate, ethoxybisphenol A dimethacrylate or urethane dimethacrylate.

6. The dental composite resin obtained by the preparation method according to any one of claims 1-5.

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