A dental composite resin with high mechanical strength and low shrinkage stress, its preparation and application

Abstract

This invention discloses a dental composite resin with high mechanical strength and low shrinkage stress, its preparation, and its application. The composite resin, by mass percentage, consists of 50-80% inorganic powder and 20-50% resin system. The resin system comprises 2.5-43.2% high-viscosity monomers containing rigid segments, 5-48.6% low-viscosity prepolymer, 20-45% low-viscosity monomers, 9.8-49.8% mercapto-acetylene resin system, and 0.4-2% photoinitiator system. The high mechanical strength and low shrinkage stress composite resin of this invention exhibits low shrinkage stress and superior mechanical strength, showing promising application prospects in dental materials.

Description

Technical Field

[0001] This invention belongs to the field of dental restorative materials, specifically relating to a dental composite resin with high mechanical strength and low shrinkage stress, and its preparation and application. Background Technology

[0002] Dental caries, commonly known as tooth decay, is one of the most common chronic diseases in the world. Statistics show that about half of the population in China suffers from dental caries, affecting all age groups. Currently, the most effective treatment for tooth decay is the removal and filling of the damaged tooth structure.

[0003] With increasing demands for aesthetic performance and biocompatibility of materials, light-cured composite resin filling materials have gradually replaced amalgam as the preferred choice for posterior tooth fillings. Dental resin-based composite materials—composite resins—have become the preferred choice for dental restorations due to their excellent mechanical properties, enamel-like appearance, and ease of clinical manipulation. Composite resins mainly consist of two components: a resin matrix (containing monomers, photopolymerization initiators, accelerators, inhibitors, and coloring compounds); and inorganic filler particles, which impart most of the mechanical properties and the required optical and radiopaque properties to the final composite resin. The most commonly used monomers in composite resins are mainly composed of dimethacrylate monomer mixtures, including bisphenol A glycidyl methacrylate (Bis-GMA), urethane dimethacrylate (UDMA), and triethylene glycol dimethacrylate (TEGDMA). Although dimethacrylate-based composite resins have many superior properties, methacrylate-based restorative resins still have some drawbacks during photochemical polymerization, including low conversion rates, polymerization shrinkage, and oxygen inhibition.

[0004] Polymerization shrinkage is the result of the conversion of intermolecular van der Waals distances between resin monomers into covalent bond lengths during light curing, mainly manifested as volume shrinkage and shrinkage stress. The polymerization of composite resins can be divided into pre-gel and post-gel stages. In the pre-gel stage, the reactive monomers exhibit sufficient mobility to rearrange and compensate for volume shrinkage without generating significant internal and interfacial stresses. After gelation, the formation of a semi-rigid polymer network hinders plastic deformation, and shrinkage stress continuously accumulates. When the composite resin restoration bonds to the cavity wall with sufficient interfacial adhesion, such as in the case of chemical bonding, shrinkage occurs under constrained conditions, and stress is transmitted to the cavity wall. If the stress level exceeds the adhesive or cohesive strength of any component of the system, it can lead to microscopic or macroscopic defects, including deformation of the restoration and tooth structure, formation of shrinkage gaps and microleakage, cusp deflection, tooth cracking, and adhesive failure. Shrinkage stress is generally considered the most important problem with current composite resin restorations and a major cause of premature restoration failure; therefore, it is necessary to develop a low-shrinkage-stress dental composite resin. Most progress in reducing the shrinkage stress of composite resins has focused on modifying the polymer network. The glass transition in the free radical polymerization of dimethacrylate significantly limits the migration rate of reactive groups at high conversion rates, leading to undesirable low conversion rates and high shrinkage stress. Compared to the chain-growth crosslinking polymerization of dimethacrylate, the stepwise growth mechanism of mercapto-ene / acetylene polymerization delays the gelation of the mercapto-ene / acetylene system, contributing to high conversion rates, less post-gel shrinkage, and lower final shrinkage stress. It also further addresses the inhibition of polymerization by oxygen, forming a low-stress homogeneous polymer network. However, due to the relatively long bond length of the final carbon-sulfur bonds, the polymer products of the mercapto-ene / acetylene system are highly flexible. When added to the methacrylate system at high concentrations, this may impair mechanical properties.

[0005] Studies have found that common causes of light-cured composite resin restoration failure in clinical practice include secondary caries and filling fracture. Meta-analysis of composite resin restorations indicates that at least 5% of these restorations are expected to fracture within 10 years, and 12% will show significant wear. Therefore, higher strength requirements are placed on dental composite resins in clinical use. Factors such as the mechanical strength of composite resins determine their durability in the oral cavity; enhancing the mechanical strength of composite resins can effectively extend the lifespan of restorations in the oral cavity.

[0006] To address the aforementioned challenges, this invention introduces a novel resin containing rigid segments and alkyne functional groups, which is then mixed with a mercapto-containing resin containing isoreactive functional groups to prepare a mercapto-alkyne resin system. When the mercapto-alkyne resin is added to dimethacrylate resin, the resulting dental composite resin can significantly reduce shrinkage stress while maintaining sufficiently high mechanical strength. Summary of the Invention

[0007] In view of the problem of high polymerization shrinkage stress in current dimethacrylate-based dental composite resins, the primary objective of this invention is to provide a dental composite resin with high mechanical strength and low shrinkage stress.

[0008] Another object of the present invention is to provide a method for preparing the above-mentioned dental composite resin with high mechanical strength and low shrinkage stress.

[0009] Another object of the present invention is to provide the application of the above-mentioned high mechanical strength and low shrinkage stress dental composite resin in dental materials.

[0010] To achieve this objective, the present invention employs the following technical solution:

[0011] In a first aspect, the present invention provides a dental composite resin with high mechanical strength and low shrinkage stress, comprising, by weight percentage, 50-80% inorganic powder and 20-50% resin system;

[0012] The resin system comprises, by weight percentage, 2.5–43.2% high-viscosity monomers containing rigid segments, 5–48.6% low-viscosity prepolymers, 20–45% low-viscosity monomers, 9.8–49.8% mercapto-acetylene resin system, and 0.4–2% photoinitiator system;

[0013] The mercapto-acetylene resin system is obtained by mixing mercapto-containing resin monomers and acetylene-containing resin monomers in a molar ratio of mercapto to acetylene of (0.9-1.1):(0.9-1.1);

[0014] The high-viscosity monomer containing rigid segments, the low-viscosity prepolymer, and the low-viscosity monomer constitute a dimethacrylate resin system, and the mass ratio of the dimethacrylate resin system to the mercapto-acetylene resin system is 90:10 to 60:40.

[0015] Preferably, the dental composite resin with high mechanical strength and low shrinkage stress comprises, by weight percentage, 50-80% inorganic powder and 20-50% resin system.

[0016] The resin system comprises, by weight percentage, 14.2–21.3% high-viscosity monomers containing rigid segments, 21.3–31.95% low-viscosity prepolymers, 23.66–35.49% low-viscosity monomers, 9.86–39.44% mercapto-acetylene resin system, and 0.4–2% photoinitiator system;

[0017] The mercapto-acetylene resin system is obtained by mixing mercapto-containing resin monomers and acetylene-containing resin monomers in a molar ratio of mercapto to acetylene of (0.9-1.1):(0.9-1.1);

[0018] The high-viscosity monomer containing rigid segments, the low-viscosity prepolymer, and the low-viscosity monomer constitute a dimethacrylate resin system, and the mass ratio of the dimethacrylate resin system to the mercapto-acetylene resin system is 90:10 to 60:40.

[0019] Preferably, the thiol-acetylene resin is a mixture of thiol-containing resin monomers and acetylene-containing resin monomers in an equimolar ratio of thiol and acetylene groups.

[0020] Preferably, the structure of the high-viscosity monomer containing rigid segments is as follows:

[0021]

[0022] R1 is independently selected from any of the following rigid link structures:

[0023] .

[0024] Preferably, the low-viscosity prepolymer is urethane dimethacrylate; more preferably, it is... .

[0025] Preferably, the low-viscosity monomer is at least one of ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, isobornyl acrylate, and tricyclo[5.2.1.02,6]decanedimethyl acrylate.

[0026] In a specific embodiment, the structures of each monomer in the dimethacrylic acid resin system are as follows:

[0027] Monomer 1: Bis-EFMA, a high-viscosity monomer containing rigid chain segments.

[0028]

[0029] Monomer 2: Low viscosity prepolymer urethane dimethacrylate (UDMA):

[0030]

[0031] Monomer 3: Low-viscosity monomer triethylene dimethacrylate (TEGDMA):

[0032]

[0033] Preferably, the structure of the acetylene-containing resin monomer is at least one of the following:

[0034]

[0035] R2 is independently selected from any of the following structures:

[0036] .

[0037] Preferably, the mercapto-containing monomer is at least one selected from ethylene glycol di(3-mercaptopropionate), 1,4-butanediol di(3-mercaptopropionate), trimethylolpropane tri(3-mercaptopropionate), and pentaerythritol tetrakis(3-mercaptopropionic acid) ester.

[0038] In a specific embodiment, the structures of each monomer in the mercapto-acetylene resin system are as follows:

[0039] Monomer 4: Propylene carbamate monomer (BYC):

[0040]

[0041] According to the present invention, the BYC synthesis route is as follows:

[0042]

[0043] Monomer 5: Propylene carbamate monomer containing allyl ether (BYCAE):

[0044]

[0045] According to the present invention, the BYCAE synthesis route is as follows:

[0046]

[0047] Monomer 6: Pentaerythritol tetrakis(3-mercaptopropionic acid) ester (PETMP) containing the thiol monomer:

[0048]

[0049] In the specific comparative example, the structures of each monomer in the mercapto-olefin resin system are as follows:

[0050] Monomer 7: Allyl ether carbamate monomer 4AEC:

[0051]

[0052] Monomer 8: Allyl ether carbamate monomer 5AEC:

[0053] .

[0054] Preferably, the photoinitiator system is at least one of a hydrogen-abstraction photoinitiator system and a cleavage photoinitiator system; the hydrogen-abstraction photoinitiator system comprises at least one photoinitiator and at least one reducing agent; the cleavage photoinitiator system comprises at least one unimolecular cleavage photoinitiator; and the photoinitiator system is sensitive to light with a wavelength of 400–500 nm.

[0055] More preferably, the hydrogen-abstracting photoinitiator system includes at least one photoinitiator selected from camphorquinone, benzophenone, and 1-phenyl-1,2-propanedione, and at least one reducing agent selected from ethyl dimethylaminobenzoate, N,N-dimethylaminoethyl ester, and dimethylaminoethyl methacrylate.

[0056] More preferably, the single-molecule cleavage photoinitiator is at least one of monoacylphosphine oxide and diacylphosphine oxide.

[0057] In a specific embodiment, the preferred hydrogen-abstracting photoinitiator is camphorquinone (CQ), and the preferred reducing agent is dimethylaminoethyl methacrylate (DMAEMA).

[0058] Preferably, the inorganic powder is silicate glass powder; the silicate glass powder contains at least one of barium, zirconium, and strontium.

[0059] Preferably, a dental composite resin with high mechanical strength and low shrinkage stress is composed of 76% inorganic powder and 24% resin system by weight percentage.

[0060] The resin system, by mass percentage, comprises 14.2–21.4% high-viscosity monomers containing rigid segments, 21.3–32.1% low-viscosity prepolymers, 23.7–35.6% low-viscosity monomers, 9.8–39.6% mercapto-acetylene resin (a mixture of mercapto resin monomers and acetylene resin monomers with equimolar reactive functional groups), 0.5–0.7% hydrogen-abstracting photoinitiator, and 0.5–0.7% reducing agent.

[0061] Secondly, the present invention provides a method for preparing the above-mentioned dental composite resin with high mechanical strength and low shrinkage stress, comprising the following steps:

[0062] (1) A resin system is prepared by mixing and stirring a high-viscosity monomer containing rigid segments, a low-viscosity prepolymer, a low-viscosity monomer, a mercapto-acetylene resin and a photoinitiator system in a certain proportion;

[0063] (2) The resin system and inorganic powder are mixed evenly in proportion to obtain a dental composite resin with high mechanical strength and low shrinkage stress.

[0064] Preferably, the mixing in steps (1) to (2) is carried out under non-light conditions, that is, under light-avoiding or lightless conditions.

[0065] Thirdly, the present invention provides the application of the above-mentioned high mechanical strength and low shrinkage stress dental composite resin in dental materials.

[0066] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0067] The composite resin described in this invention employs various resins containing rigid segments and introduces mercapto-alkyne for stepwise polymerization to delay the gel point, thereby reducing the shrinkage stress of the composite resin and improving its double bond conversion rate while ensuring sufficiently high mechanical strength. Attached Figure Description

[0068] Figure 1 H is the H of propargyl carbamate monomer (BYC, monomer 4) 1 NMR characterization results.

[0069] Figure 2 The results are FTIR characterization of propargyl carbamate monomer (BYC, monomer 4).

[0070] Figure 3 H is a propargyl carbamate monomer containing allyl ether (BYCAE, monomer 5). 1 NMR characterization results.

[0071] Figure 4 The results are FTIR characterizations of the allyl ether-containing propargyl carbamate monomer (BYCAE, monomer 5). Detailed Implementation

[0072] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto.

[0073] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0074] The propargyl carbamate monomer (BYC, monomer 4) used in the examples was prepared according to the following method:

[0075] Weigh 0.1 mol of isophorone diisocyanate (IPDI), 0.2 mol of 3-butyn-1-ol, 3 drops of dibutyltin dilaurate (DBTDL), and 40 mL of ultra-dry acetone (AC) into a 250 mL round-bottom flask. Place the flask in a 40°C magnetically stirred oil bath and heat to react. When the reaction system reaches 2267 cm⁻¹... -1 The reaction ended when the infrared absorption peak of the isocyanate group no longer appeared. Subsequently, the solvent in the reaction system was removed using a rotary evaporator to obtain a transparent viscous liquid, which was named propargyl carbamate monomer (BYC).

[0076] Characterization results of the synthesized product:

[0077] (1) H 1 NMR characterization results:

[0078] 1 ¹H NMR (600 MHz, CDCl₃-d, δ): 4.83–4.41 (m, 2H; NH), 4.09 (dt, J = 12.7, 6.7 Hz, 4H; CH₂), 3.81–3.57 (m, 1H; CH), 3.31–2.78 (m, 2H; CH₂), 2.57–2.31 (m, 4H; CH₂), 2.02–1.87 (m, 2H; CH, alkynyl), 1.36–0.69 (m, 15H; CH₂, CH₃). Results are as follows: Figure 1 As shown.

[0079] (2) FTIR characterization results:

[0080] IR(KBr):ν(cm) -1 =3301(s;ν(CH, ynyl)), 3336(s;ν(NH)), 3066(w;ν(NH)), 1531, 1236(w, δ(NH)); 2954, 2846(s;ν(CH3)), 2912(s;ν(CH2)), 1462(w; δ(CH2)), 2120(m, ν(ynyl)); 1705(s, ν(carbonyl)), the results are as follows Figure 2 As shown.

[0081] The allyl ether-containing propargyl carbamate monomer (BYCAE, monomer 5) used in the examples was prepared according to the following method:

[0082] 0.1 mol of isophorone diisocyanate (IPDI) was weighed into a 250 mL three-necked flask, and 3 drops of dibutyltin dilaurate (DBTDL) were added as a catalyst. An appropriate amount of ultra-dry acetone (AC) was added, and the flask was placed in a magnetically stirred oil bath and stirred thoroughly. Then, an acetone solution containing 0.05 mL of trimethylolpropane allyl ether was slowly added dropwise through a constant-pressure dropping funnel. The reaction was carried out at 40 °C. When the isocyanate group content was determined by titration to be half of the initial content, 0.1 mL of trimethylolpropane diallyl ether (TMPDE) was added to the three-necked flask to continue the reaction. When the reaction system reached 2267 cm⁻¹... -1 The reaction ended when the infrared absorption peak of the isocyanate group no longer appeared. Subsequently, the solvent in the reaction system was removed using a rotary evaporator to obtain a transparent viscous liquid, which was named allyl ether-containing propargyl carbamate monomer (BYCAE).

[0083] Characterization results of the synthesized product:

[0084] (1) H 1 NMR characterization results:

[0085] 1 ¹H NMR (600 MHz, CDCl₃-d, δ): 5.82–5.75 (ddt, J = 16.0, 10.5, 5.4 Hz, 1H: CH, alkenyl), 5.19–5.07 (dd, J = 56.2, 13.9 Hz, 2H: CH₂, alkenyl), 4.83 (m, 2H; NH), 4.61–4.38 (m, 2H; NH), 4.11–4.08 (t, J = 6.7 Hz, 4H; CH₂), 4.01–3.81 (m, 6H; CH₂), 3.70–3.67 (t, J = 6.3 Hz). Hz, 3H; CH, CH2), 3.29–2.77 (m, 4H; CH2), 2.62–2.30 (m, 4H; CH2), 1.97–1.94 (dt, J = 19.4, 2.8 Hz, 2H; CH, alkynyl), 1.84–0.63 (m, 35H; CH2, CH3), results as follows Figure 3 As shown.

[0086] (2) FTIR characterization results:

[0087] IR(KBr):ν(cm) -1=3303(s;ν(CH, ynyl)), 3334(s;ν(NH)), 3066(w;ν(NH),ν(CH, vinyl)), 1527, 1238(w, δ(NH)); 2962, 2852(s;ν(CH3)); 2921(s;ν(CH2)), 1462(w; δ(CH2)); 2121(m, ν(ynyl)); 1714(s, ν(carbonyl)); 1647(m; ν(alkenyl)), the results are as follows Figure 4 As shown.

[0088] Compare with Example 1

[0089] 23.66% Bis-EFMA (monomer 1, a high-viscosity monomer Bis-EFMA containing rigid segments), 35.50% urethane dimethacrylate (low-viscosity prepolymer, UDMA), 39.44% triethylene glycol methacrylate (low-viscosity monomer, TEGDMA), 0.7% camphorquinone (CQ), and 0.7% dimethylaminoethyl methacrylate (DMAEMA). The components were weighed according to their mass percentages and mixed uniformly in the dark to obtain the resin system of Comparative Example 1. This resin system was then mixed uniformly with barium glass powder (GM27884, SCHOTT AG) at a mass ratio of 24:76 using high-speed mixing to obtain Comparative Example 1.

[0090] Example 1

[0091] The total resin system comprises: 21.30% Bis-EFMA (monomer 1, a high-viscosity monomer Bis-EFMA containing rigid segments), 31.95% urethane dimethacrylate (low-viscosity prepolymer, UDMA), 35.49% triethylene glycol dimethacrylate (low-viscosity monomer, TEGDMA), 4.20% propargyl urethane monomer BYC (monomer 4), 5.66% pentaerythritol tetrakis(3-mercaptopropionic acid) ester (PETMP), and 1.4% photoinitiator system (the photoinitiator system consists of 50% camphorquinone (CQ) and 50% dimethylaminoethyl methacrylate (DMAEMA)). The mass ratio of the dimethacrylate resin system composed of Bis-EFMA, UDMA, and TEGDMA to the mercapto-alkynyl resin system composed of monomer 4 and PETMP is 90:10. The components were weighed according to their mass percentages and then mixed uniformly in the dark to obtain the resin system of Example 1. Example 1 was prepared by mixing the resin system with barium glass powder (GM27884, SCHOTTAG) at a mass ratio of 24:76 using high speed.

[0092] Example 2

[0093] The total resin system consisted of: 18.93% Bis-EFMA (monomer 1, a high-viscosity monomer containing rigid segments, Bis-EFMA), 28.40% urethane dimethacrylate (low-viscosity prepolymer, UDMA), 31.55% triethylene glycol dimethacrylate (low-viscosity monomer, TEGDMA), 8.40% propargyl urethane monomer BYC (monomer 4), 11.32% pentaerythritol tetrakis(3-mercaptopropionic acid) ester (PETMP), and 1.4% photoinitiator system (the photoinitiator system consisted of 50% camphorquinone (CQ) and 50% dimethylaminoethyl methacrylate (DMAEMA)). The mass ratio of the dimethacrylate resin system composed of Bis-EFMA, UDMA, and TEGDMA to the mercapto-acetylene resin system composed of monomer 4 and PETMP was 80:20. The components were weighed according to their mass percentages and then mixed uniformly in the dark to obtain the resin system of Example 2. Example 2 was prepared by mixing the resin system with barium glass powder (GM27884, SCHOTTAG) at a mass ratio of 24:76 using high speed.

[0094] Example 3

[0095] The total resin system consisted of: 16.56% Bis-EFMA (monomer 1, a high-viscosity monomer containing rigid segments, Bis-EFMA), 24.85% urethane dimethacrylate (low-viscosity prepolymer, UDMA), 27.61% triethylene glycol dimethacrylate (low-viscosity monomer, TEGDMA), 12.60% propargyl urethane monomer BYC (monomer 4), 16.98% pentaerythritol tetrakis(3-mercaptopropionic acid) ester (PETMP), and 1.4% photoinitiator system (the photoinitiator system consisted of 50% camphorquinone (CQ) and 50% dimethylaminoethyl methacrylate (DMAEMA)). The mass ratio of the dimethacrylate resin system composed of Bis-EFMA, UDMA, and TEGDMA to the mercapto-alkynyl resin system composed of monomer 4 and PETMP was 70:30. The components were weighed according to their mass percentages and then mixed uniformly in the dark to obtain the resin system of Example 3. Example 3 was prepared by mixing the resin system with barium glass powder (GM27884, SCHOTT AG) at a mass ratio of 24:76 using high speed.

[0096] Example 4

[0097] The total resin system consisted of: 14.20% Bis-EFMA (monomer 1, a high-viscosity monomer containing rigid segments, Bis-EFMA), 21.30% urethane dimethacrylate (low-viscosity prepolymer, UDMA), 23.66% triethylene glycol dimethacrylate (low-viscosity monomer, TEGDMA), 16.79% propargyl urethane monomer BYC (monomer 4), 22.65% pentaerythritol tetrakis(3-mercaptopropionic acid) ester (PETMP), and 1.4% photoinitiator system (the photoinitiator system consisted of 50% camphorquinone (CQ) and 50% dimethylaminoethyl methacrylate (DMAEMA)). The mass ratio of the dimethacrylate resin system composed of Bis-EFMA, UDMA, and TEGDMA to the mercapto-alkynyl resin system composed of monomer 4 and PETMP was 60:40. The components were weighed according to their mass percentages and then mixed uniformly in the dark to obtain the resin system of Example 4. Example 4 was prepared by mixing the resin system with barium glass powder (GM27884, SCHOTT AG) at a mass ratio of 24:76 at high speed.

[0098] Comparative Example 2

[0099] Same as Example 4, except that its propargyl carbamate monomer BYC (monomer 4) is replaced with allyl ether carbamate monomer 4AEC (monomer 7).

[0100] Polymer volume shrinkage, shrinkage stress, flexural strength and compressive strength were tested for Comparative Example 1 and Examples 1-4, and the results are shown in Table 1.

[0101] Table 1. Performance of Comparative Example 1 and Examples 1-4

[0102]

[0103] Example 6

[0104] The total resin system comprises: 21.30% Bis-EFMA (monomer 1, a high-viscosity monomer containing rigid segments, Bis-EFMA), 31.95% urethane dimethacrylate (low-viscosity prepolymer, UDMA), 35.49% triethylene glycol dimethacrylate (low-viscosity monomer, TEGDMA), 5.46% propargyl urethane monomer containing allyl ether, BYCAE (monomer 5), 4.40% pentaerythritol tetrakis(3-mercaptopropionic acid) ester (PETMP), and 1.4% photoinitiator system (the photoinitiator system comprises 50% camphorquinone (CQ) and 50% dimethylaminoethyl methacrylate (DMAEMA)). The mass ratio of the dimethacrylate resin system composed of Bis-EFMA, UDMA, and TEGDMA to the mercapto-acetylene resin system composed of monomer 5 and PETMP is 90:10. The components were weighed according to their mass percentages and then mixed uniformly in the dark to obtain the resin system of Example 6. Example 6 was prepared by mixing the resin system with barium glass powder (GM27884, SCHOTT AG) at a mass ratio of 24:76 at high speed.

[0105] Example 7

[0106] The total resin system comprises: 18.93% Bis-EFMA (monomer 1, a high-viscosity monomer containing rigid segments, Bis-EFMA), 28.40% urethane dimethacrylate (low-viscosity prepolymer, UDMA), 31.55% triethylene glycol dimethacrylate (low-viscosity monomer, TEGDMA), 10.92% propargyl urethane monomer containing allyl ether, BYCAE (monomer 5), 8.80% pentaerythritol tetrakis(3-mercaptopropionic acid) ester (PETMP), and 1.4% photoinitiator system (the photoinitiator system comprises 50% camphorquinone (CQ) and 50% dimethylaminoethyl methacrylate (DMAEMA)). The mass ratio of the dimethacrylate resin system composed of Bis-EFMA, UDMA, and TEGDMA to the mercapto-acetylene resin system composed of monomer 5 and PETMP is 80:20. The components were weighed according to their mass percentages and then mixed uniformly in the dark to obtain the resin system of Example 7. Example 7 was prepared by mixing the resin system with barium glass powder (GM27884, SCHOTT AG) at a mass ratio of 24:76 at high speed.

[0107] Example 8

[0108] The total resin system consisted of: 16.56% Bis-EFMA (monomer 1, a high-viscosity monomer containing rigid segments, Bis-EFMA), 24.85% urethane dimethacrylate (low-viscosity prepolymer, UDMA), 27.61% triethylene glycol dimethacrylate (low-viscosity monomer, TEGDMA), 16.39% allyl ether-containing propargyl urethane monomer BYCAE (monomer 5), 13.19% pentaerythritol tetrakis(3-mercaptopropionic acid) ester (PETMP), and 1.4% photoinitiator system (the photoinitiator system consisted of 50% camphorquinone (CQ) and 50% dimethylaminoethyl methacrylate (DMAEMA)). The mass ratio of the dimethacrylate resin system composed of Bis-EFMA, UDMA, and TEGDMA to the mercapto-acetylene resin system composed of monomer 5 and PETMP was 70:30. The components were weighed according to their mass percentages and then mixed uniformly in the dark to obtain the resin system of Example 8. Example 8 was prepared by mixing the resin system with barium glass powder (GM27884, SCHOTT AG) at a mass ratio of 24:76 at high speed.

[0109] Example 9

[0110] The total resin system comprises: 14.20% Bis-EFMA (monomer 1, a high-viscosity monomer containing rigid segments, Bis-EFMA), 21.30% urethane dimethacrylate (low-viscosity prepolymer, UDMA), 23.66% triethylene glycol dimethacrylate (low-viscosity monomer, TEGDMA), 21.85% propargyl urethane monomer containing allyl ether, BYCAE (monomer 5), 17.59% pentaerythritol tetrakis(3-mercaptopropionic acid) ester (PETMP), and 1.4% photoinitiator system (the photoinitiator system consists of 50% camphorquinone (CQ) and 50% dimethylaminoethyl methacrylate (DMAEMA)). The mass ratio of the dimethacrylate resin system composed of Bis-EFMA, UDMA, and TEGDMA to the mercapto-acetylene resin system composed of monomer 5 and PETMP is 60:40. The components were weighed according to their mass percentages and then mixed uniformly in the dark to obtain the resin system of Example 9. Example 9 was prepared by mixing the resin system with barium glass powder (GM27884, SCHOTT AG) at a mass ratio of 24:76 using high speed.

[0111] Comparative Example 3

[0112] Same as Example 9, except that its allyl ether-containing propargyl carbamate monomer BYCAE (monomer 5) is replaced with an allyl ether-containing carbamate monomer 5AEC (monomer 8).

[0113] Polymerization volume shrinkage rate, shrinkage stress, flexural strength and compressive strength were tested for Comparative Example 1 and Examples 6-9. The results are shown in Table 2.

[0114] Table 2. Performance of Comparative Example 1 and Examples 6-9

[0115]

[0116] As shown in Tables 1 and 2, when using pure dimethicone resin alone, the flexural strength of the dental composite resin reaches 122 MPa, meeting the minimum requirement of greater than 80 MPa for dental materials in ISO 4049:2019. However, the shrinkage stress of the dental composite resin is 2.9 MPa, which negatively impacts the clinical filling treatment effect. When a mercapto-acetylene resin system is prepared by introducing propargyl urethane monomer BYC (monomer 4) and pentaerythritol tetrakis(3-mercaptopropionic acid) (PETMP), the shrinkage stress decreases significantly with increasing BYC / PETMP content, reaching a minimum of 0.7 MPa, a decrease of 76%, while exhibiting superior mechanical strength. When a mercapto-alkynyl resin system was prepared by introducing allyl ether-containing propargyl carbamate monomer BYCAE (monomer 5) and pentaerythritol tetrakis(3-mercaptopropionic acid) (PETMP), the shrinkage stress also achieved a significant decrease with the increase of BYCAE / PETMP content, and the minimum shrinkage stress reached 0.7 MPa, a decrease of 76%, which also showed better mechanical strength compared to control group 1.

[0117] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A dental composite resin with high mechanical strength and low shrinkage stress, characterized in that, By weight percentage, it comprises 50–80% inorganic powder and 20–50% resin system; The resin system comprises, by weight percentage, 2.5–43.2% high-viscosity monomers containing rigid segments, 5–48.6% low-viscosity prepolymers, 20–45% low-viscosity monomers, 9.8–49.8% mercapto-acetylene resin system, and 0.4–2% photoinitiator system; The mercapto-acetylene resin system is obtained by mixing mercapto-containing resin monomers and acetylene-containing resin monomers in a molar ratio of mercapto to acetylene of (0.9-1.1):(0.9-1.1); The high-viscosity monomer containing rigid segments, the low-viscosity prepolymer, and the low-viscosity monomer constitute a dimethacrylate resin system, and the mass ratio of the dimethacrylate resin system to the mercapto-acetylene resin system is 90:10 to 60:

40.

2. The dental composite resin according to claim 1, characterized in that, By weight percentage, it comprises 50–80% inorganic powder and 20–50% resin system; The resin system comprises, by weight percentage, 14.2–21.3% high-viscosity monomers containing rigid segments, 21.3–31.95% low-viscosity prepolymers, 23.66–35.49% low-viscosity monomers, 9.86–39.44% mercapto-acetylene resin system, and 0.4–2% photoinitiator system; The mercapto-acetylene resin system is obtained by mixing mercapto-containing resin monomers and acetylene-containing resin monomers in a molar ratio of mercapto to acetylene of (0.9-1.1):(0.9-1.1); The high-viscosity monomer containing rigid segments, the low-viscosity prepolymer, and the low-viscosity monomer constitute a dimethacrylate resin system, and the mass ratio of the dimethacrylate resin system to the mercapto-acetylene resin system is 90:10 to 60:

40.

3. The dental composite resin according to claim 1, characterized in that, The structure of the acetylene-containing resin monomer is at least one of the following: ， R2 is independently selected from any of the following structures: ； And / or, the mercapto-containing monomer is at least one selected from ethylene glycol di(3-mercaptopropionate), 1,4-butanediol di(3-mercaptopropionate), trimethylolpropane tri(3-mercaptopropionate), and pentaerythritol tetrakis(3-mercaptopropionic acid) ester.

4. The dental composite resin according to claim 1, 2, or 3, characterized in that, The thiol-acetylene resin is made by mixing thiol-containing resin monomers and acetylene-containing resin monomers in an equimolar ratio of thiol and acetylene groups.

5. The dental composite resin according to claim 1, 2, or 3, characterized in that, The structure of the high-viscosity monomer containing rigid segments is shown below: ， R1 is independently selected from any of the following rigid link structures: ； And / or, the low-viscosity prepolymer is urethane dimethacrylate; more preferably, it is... ; And / or, the low viscosity monomer is at least one of ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, isobornyl acrylate (meth)acrylate, and tricyclo[5.2.1.02,6]decanedimethyl acrylate; And / or, the photoinitiator system is sensitive to light with a wavelength of 400–500 nm.

6. The dental composite resin according to claim 1, 2, or 3, characterized in that, The photoinitiator system is at least one of a hydrogen-abstracting photoinitiator system and a pyrolysis photoinitiator system; The hydrogen-abstracting photoinitiator system comprises at least one photoinitiator and at least one reducing agent; The cleavage photoinitiator system contains at least one monomolecule cleavage photoinitiator.

7. The dental composite resin according to claim 6, characterized in that, The hydrogen-abstracting photoinitiator system includes at least one photoinitiator selected from camphorquinone, benzophenone and 1-phenyl-1,2-propanedione, and at least one reducing agent selected from ethyl dimethylaminobenzoate, N,N-dimethylaminoethyl ester and dimethylaminoethyl methacrylate. And / or, the single-molecule cleavage photoinitiator is at least one of monoacylphosphine oxide and diacylphosphine oxide.

8. The dental composite resin according to claim 1, 2, or 3, characterized in that, The inorganic powder is silicate glass powder; the silicate glass powder contains at least one of barium, zirconium and strontium.

9. A method for preparing a dental composite resin with high mechanical strength and low shrinkage stress according to any one of claims 1 to 8, characterized in that, Includes the following steps: (1) A resin system is prepared by mixing and stirring a high-viscosity monomer containing rigid segments, a low-viscosity prepolymer, a low-viscosity monomer, a mercapto-acetylene resin and a photoinitiator system in a certain proportion; (2) The resin system and inorganic powder are mixed evenly in proportion to obtain a dental composite resin with high mechanical strength and low shrinkage stress.

10. The application of the dental composite resin with high mechanical strength and low shrinkage stress as described in any one of claims 1 to 8 in dental materials.

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