Paste resin, preparation method and application thereof

Abstract

The present invention provides a paste resin, which is prepared from the following raw materials: 10-30wt% of a resin matrix composition, 0.5-5wt% of porous spherical silica gel, 60-85wt% of a modified inorganic filler, 0.1-5.0wt% of a chain transfer agent, and the remainder of additives; the resin matrix composition includes a polymerized resin monomer, an active diluent, a photoinitiator, and a photoinitiator accelerator. The cream resin provided by the present application reduces the adhesion of the paste resin to dental resin filling devices by adding porous spherical silica gel, improves the convenience of clinical operation, and introduces a CTA chain transfer agent to reduce polymerization shrinkage and reduce the occurrence of secondary caries.

Description

Technical Field

[0001] The present invention relates to the technical field of medical materials, and in particular to a paste resin, a preparation method thereof and an application thereof. Background Art

[0002] Light-curing composite resins for dental restorations are mainly composed of a polymerizable resin matrix, inorganic fillers, a photoinitiator system and other additives. Due to their aesthetics, ease of operation and good biocompatibility, they meet the needs of clinicians and patients for cosmetic dental restorations and have become the most widely used restorative material for the treatment of tooth defects. However, the polymerization shrinkage that occurs during the curing of light-curing composite resin materials seriously affects the service life of the restoration.

[0003] The volume shrinkage rate of conventional dental composite resins after polymerization is large, and its volume shrinkage rate generally exceeds 2%, thereby destroying the marginal sealing of the restoration, causing enamel fracture, tooth cusp fracture, post-filling sensitivity, microleakage and secondary caries, etc., which seriously affects the long-term use of the restoration. Therefore, controlling the polymerization shrinkage of light-cured composite resins through various means is a hot issue in the research of dental resin materials; for example, polymerization shrinkage has been reduced by adding hyperbranched monomers, nanogels or nanotubes and low shrinkage additives or expandable fillers. Specifically, the Chinese patent with publication number CN111228124A discloses that by adding an allyl sulfone or vinyl sulfone ester with a special structure as a transfer agent, they cause crosslinking of the material, wherein the crosslinking is unstable and can be cleaved and reformed during polymerization, which can reduce the polymerization shrinkage rate. WO2015 / 057413A1 discloses an addition-fragmentation oligomer containing a disulfide group at the allyl position, which is added to a free radical polymerizable material, wherein the unstable bond can be cleaved and reformed during polymerization, which can reduce the polymerization shrinkage rate.

[0004] However, the mechanical strength of the composite material with low shrinkage stress in the above patent is significantly reduced after curing (flexural strength <110Mpa), and the effect of reducing polymerization shrinkage is insufficient (polymerization shrinkage is greater than 1.5%). In addition, the existing paste resin for dental restoration generally has the problem of sticking to instruments. The greater the deformation of the resin caused by the instrument during the operation, the worse the operation convenience, which is not conducive to the doctor's carving of the resin shape. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a paste resin which, as a material for dental restoration, can reduce adhesion to instruments, reduce shrinkage stress and reduce polymerization shrinkage rate.

[0006] In view of this, the present application provides a paste resin prepared from the following raw materials:

[0007]

[0008] Additive residue;

[0009] The resin matrix composition includes polymerized resin monomers, reactive diluents, photoinitiators and photoinitiator accelerators;

[0010] The chain transfer agent has a structure shown in formula (I);

[0011]

[0012] Wherein, R is selected from S, carbonyl or phenyl.

[0013] Preferably, the preparation method of the porous spherical silica gel is specifically as follows:

[0014] The aqueous silica sol is mixed with urea and formaldehyde, and copolymerized under acidic conditions to obtain a composite sphere;

[0015] The composite sphere is ashed at high temperature and then sintered at high temperature to obtain porous spherical silica gel.

[0016] Preferably, the preparation method of the modified inorganic filler is specifically as follows:

[0017] mixing the filler with the organic solvent to obtain a filler slurry;

[0018] The silane coupling agent is pre-hydrolyzed and then mixed with the filler slurry, and dried after the reaction.

[0019] Preferably, the modified inorganic filler consists of an inorganic particle filler and an inorganic ultrafine particle in a mass ratio of (2 to 20): 1; the inorganic particle filler is selected from one or more of glass powder, strontium glass powder, silica, composite oxide particles, ceramics, zirconium oxide and ytterbium fluoride, and its average particle size is 0.5-1.0 μm; the inorganic ultrafine particle is selected from one or more of silica, alumina, zirconium oxide, hydroxyapatite, zinc oxide, calcium phosphate, composite oxide particles and ytterbium fluoride, and its average particle size is 0.05 to 0.2 μm.

[0020] Preferably, the polymer resin monomer is selected from one or more of bisphenol A-dimethacrylate glycidyl ester, ethoxylated bisphenol A dimethacrylate, dimethacrylate urethane and aromatic dimethacrylate diisocyanate; the reactive diluent is selected from one or more of triethylene glycol dimethacrylate, 1,12-dodecanediol dimethacrylate and 1,6-hexanediol diacrylate; the photoinitiator is selected from camphorquinone, and the photoinitiator accelerator is selected from ethyl p-N,N-dimethylaminobenzoate.

[0021] Preferably, the porous spherical silica gel has an average particle size of 0.2 to 5 μm and a specific surface area of ​​1000 to 1500 m 2 / g.

[0022] Preferably, the resin matrix composition further comprises a polymerization inhibitor and an anti-aging agent, wherein the polymerization inhibitor is selected from 4-methoxyphenol, and the anti-aging agent is selected from 2-hydroxy-4-methoxybenzophenone.

[0023] Preferably, the additive comprises titanium dioxide treated with a silane coupling agent, and the average particle size of the titanium dioxide is 50 to 80 nm.

[0024] The present application also provides a method for preparing the paste resin, comprising the following steps:

[0025] Mixing a polymer resin monomer, a reactive diluent, a photoinitiator and a photoinitiator accelerator to obtain a resin matrix composition;

[0026] The resin matrix composition, porous spherical silica gel, modified inorganic filler, chain transfer agent and additives are mixed to obtain a paste resin.

[0027] The present application also provides a material for dental restoration, including a paste resin, wherein the paste resin is the paste resin described above or a paste resin prepared by the preparation method described above.

[0028] The present application provides a paste resin, which is prepared from a specific content of a resin matrix composition, porous spherical silica gel, a modified inorganic filler, a chain transfer agent and an additive; the paste resin provided by the present application introduces porous spherical silica gel, which has an adsorption effect on the resin matrix in the resin, combines with the free resin matrix to reduce the adhesion to the dental resin filling device, and is beneficial to improving the convenience of clinical operation; at the same time, the introduction of a special chain transfer agent, during the monomer polymerization process, the free radical charge is temporarily transferred from the macromolecular free radical to the chain transfer agent, and the chain transfer agent restarts a new polymer chain by reacting with the monomer or other polymers, thereby achieving the purpose of reducing shrinkage stress and reducing polymerization shrinkage rate through continuous breaking and recombination of molecular chains. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the deformation height test of the sample of the present invention. DETAILED DESCRIPTION

[0030] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0031] In view of the fact that the paste resin for dental restoration in the prior art is insufficient in reducing the polymerization shrinkage rate and has the problem of sticking to the device, the present application provides a paste resin, which avoids the adhesion to the dental resin filling device by introducing porous spherical silica gel and chain transfer agent, and also reduces the shrinkage stress and the polymerization shrinkage rate. Specifically, the embodiment of the present invention discloses a paste resin prepared from the following raw materials:

[0032]

[0033] Additive residue;

[0034] The resin matrix composition includes polymerized resin monomers, reactive diluents, photoinitiators and photoinitiator accelerators;

[0035] The chain transfer agent has a structure shown in formula (I);

[0036]

[0037] Wherein, R is selected from S, carbonyl or phenyl.

[0038] In the paste resin provided in the present application, the resin matrix composition includes a polymerized resin monomer, a reactive diluent, a photoinitiator and a photoinitiator accelerator; wherein the polymerized resin monomer is selected from one or more of bisphenol A-dimethacrylate glycidyl ester, ethoxylated bisphenol A dimethacrylate, dimethacrylate urethane formate and aromatic dimethacrylate diisocyanate; the reactive diluent is selected from one or more of triethylene glycol dimethacrylate, 1,12-dodecanediol dimethacrylate and 1,6-hexanediol diacrylate; the photoinitiator is selected from camphorquinone, and the photoinitiator accelerator is selected from ethyl para-N,N-dimethylaminobenzoate. Further, the resin-based composition also includes an inhibitor and an anti-aging agent, wherein the inhibitor is selected from 4-methoxyphenol, and the anti-aging agent is selected from 2-hydroxy-4-methoxybenzophenone. Specifically, based on the total amount of the resin matrix composition, the content of the polymerized resin monomer is 40-70wt%, the content of the reactive diluent is 20-50wt%, the content of the photoinitiator is 1-5wt%, the content of the photoinitiator accelerator is 1-5wt%, the content of the inhibitor is 0.3-1.0wt%, and the content of the antioxidant is 0.3-1.0wt%. Based on the total amount of the paste resin, the content of the resin matrix composition is 10-30wt%, specifically, 12-28wt% of the resin matrix composition, and more specifically, the content of the resin matrix composition is 18-22wt%.

[0039] The porous spherical silica gel described in the present application has an average particle size of 0.2 to 5 μm and a specific surface area of ​​1000 to 1500 m2 / g. The preparation method of the porous spherical silica gel described in the present application is specifically as follows:

[0040] The aqueous silica sol is mixed with urea and formaldehyde, and copolymerized under acidic conditions to obtain a composite sphere;

[0041] The composite sphere is ashed at high temperature and then sintered at high temperature to obtain porous spherical silica gel.

[0042] In the above preparation process, the aqueous silica sol is obtained by dispersing nano-silicon dioxide in an aqueous solution; the ashing is performed to remove organic matter therein to form porous silica gel, and the ashing temperature is 400-600°C for 3-8 hours; the high-temperature sintering temperature is 800-1200°C for 2-5 hours; the high-temperature sintering further improves the mechanical strength of the porous silica gel.

[0043] The porous spherical silica gel of the present application has an adsorption effect on the resin matrix in the resin, and can combine with the free resin matrix, thereby reducing the adhesion of the paste resin to the dental resin filling device.

[0044] The modified inorganic filler is an inorganic filler modified by a silane coupling agent, and the specific process is as follows:

[0045] mixing the filler with the organic solvent to obtain a filler slurry;

[0046] The silane coupling agent is pre-hydrolyzed and then mixed with the filler slurry, and dried after the reaction.

[0047] The silane coupling agent is specifically selected from KH570 silane coupling agent, and the pre-hydrolysis is to prepare an alcohol aqueous solution with anhydrous ethanol and water, and then add glacial acetic acid to adjust the pH to 3-4, and stir at 100-200° C. for 30-60 minutes. The KH silane coupling agent is 2-10wt% of the filler.

[0048] The modified inorganic filler described in the present application is composed of an inorganic particle filler modified by a silane coupling agent and an inorganic ultrafine particle modified by a silane coupling agent, and the mass ratio of the two is (2-20):1. Specifically, the mass ratio of the modified inorganic particle filler to the modified inorganic ultrafine particle is (5-15):1. The inorganic particle filler is selected from one or more of glass powder, barium aluminum strontium glass powder, silicon dioxide, composite oxide particles, ceramics, zirconium oxide and ytterbium fluoride, and its average particle size is 0.5-1.0 μm; the inorganic ultrafine particle is selected from one or more of silicon dioxide, aluminum oxide, zirconium oxide, hydroxyapatite, zinc oxide, calcium phosphate, composite oxide particles and ytterbium fluoride, and its average particle size is 0.05-0.2 μm. After modification, the inorganic filler has lipophilicity and good compatibility with the resin matrix composition, thereby improving the dispersibility of the inorganic filler in the resin matrix. The content of the modified inorganic filler is 60 to 85 wt %. Specifically, the content of the modified inorganic filler is 65 to 80 wt %. More specifically, the content of the modified inorganic filler is 67 to 78 wt %.

[0049] The chain transfer agent described in the present application is specifically selected from the structure shown in formula (I);

[0050]

[0051] Wherein, R is selected from S, carbonyl or phenyl.

[0052] In the process of monomer polymerization, the chain transfer agent of the present application temporarily transfers the free radical charge from the macromolecular free radical to the chain transfer agent, which restarts the new polymer chain by reacting with the monomer or other polymer, thereby achieving the purpose of reducing shrinkage stress and polymerization shrinkage rate through continuous breaking and reorganization of the molecular chain. The content of the chain transfer agent is 0.1-5.0wt%, specifically, the content of the chain transfer agent is 0.5-3.5wt%.

[0053] According to the present invention, the additive may specifically include titanium dioxide modified by a silane coupling agent, and the average particle size of the titanium dioxide is 50 to 80 nm.

[0054] The present application also provides a method for preparing a paste resin, comprising the following steps:

[0055] Mixing a polymer resin monomer, a reactive diluent, a photoinitiator and a photoinitiator accelerator to obtain a resin matrix composition;

[0056] The resin matrix composition, porous spherical silica gel, modified inorganic filler, chain transfer agent and additives are mixed to obtain a paste resin.

[0057] Furthermore, the present application also provides a material for dental restoration, which includes a paste resin, and the paste resin is specifically the paste resin described in the above scheme.

[0058] The present invention provides a paste resin, which is added with porous spherical silica gel to dental composite resin. Since the porous spherical silica gel powder has an adsorption effect on the resin matrix, it is beneficial to combine with the free resin matrix to reduce the adhesion to the dental resin filling device, thereby improving the convenience of clinical operation; on the other hand, a chain transfer agent is introduced. During the monomer polymerization process, the free radical charge is temporarily transferred from the macromolecular free radical to the CTA chain transfer agent. The CTA chain transfer agent restarts the new polymer chain by reacting with the monomer or other polymers, thereby achieving the purpose of reducing shrinkage stress and reducing polymerization shrinkage through the continuous breaking and recombination of the molecular chain. Therefore, the paste resin provided by the present invention has good clinical operability and extremely low polymerization shrinkage rate in clinical practice.

[0059] In order to further understand the present invention, the paste resin provided by the present invention, its preparation method and application are described in detail below in conjunction with embodiments. The protection scope of the present invention is not limited by the following embodiments.

[0060] A) Preparation of spherical porous silica powder:

[0061] Prepare aqueous silica sol (30nm silica dispersed in aqueous solution with a mass content of 20%); then mix the aqueous silica sol with urea and formaldehyde, and copolymerize under acidic conditions to form composite microspheres; in a muffle furnace, remove organic matter through high-temperature ashing at 500°C for 5h to form porous silica gel, and then raise the temperature to 1000°C for sintering to further improve the mechanical strength of the porous silica gel, thereby obtaining spherical porous silica gel powder.

[0062] B) Preparation of modified inorganic filler:

[0063] (1) Weigh a certain amount of filler and add it to an anhydrous ethanol solution to prepare a filler slurry, and then ultrasonically treat it for 30 minutes;

[0064] (2) preparing an alcohol-water solution by mixing anhydrous ethanol and water in a certain proportion, and adding glacial acetic acid to adjust the pH value of the solution to 3.0, and then adding KH570 silane coupling agent, the mass ratio of ethanol, water and silane coupling agent is 5:3:2, and performing a pre-hydrolysis reaction under heating at 120° C. with magnetic stirring for 60 min until the silane coupling agent is completely hydrolyzed, wherein the amount of KH570 silane coupling agent is 3% of the mass content of the filler;

[0065] (3) The hydrolyzed silane solution is added dropwise to the filler slurry under stirring, and the heating temperature is increased to 150° C., magnetic stirring is performed for 2 h, and then vacuum drying is performed at 100° C. for 10 h to obtain a modified inorganic filler.

[0066] C) The spherical porous silica gel powder and modified inorganic filler used in the following examples are prepared according to the above method, and the abbreviations of the materials used in the following examples are shown in Table 1:

[0067] Table 1 Statistical table of the abbreviations of materials involved in the examples

[0068]

[0069] D) The performance test of the paste resin of this embodiment is carried out by the following method:

[0070] Flexural strength and elastic modulus test: According to the ISO 4049:2009 test standard, the sample was injected into a 2mm×2mm×25mm metal mold to make a test piece. The surface and bottom of the test piece were covered with polyester film to prevent the matrix from flowing out and the existence of an anaerobic layer. The test piece was cured by a visible light curing lamp, and 5 points were overlapped from left to right, and each point was illuminated for 20 seconds to ensure sufficient curing. The test piece was then stored in 37℃ distilled water and kept away from light for 24 hours. A universal testing machine was used to test the three-point bending strength and elastic modulus of the test piece. The sample was loaded at a loading speed of 0.75mm / min until the sample broke, and the maximum load and slope applied when the sample reached the breaking point were recorded. Finally, the flexural strength and elastic modulus were calculated according to the ISO 4049:2009 test standard formula.

[0071] Volume shrinkage test: According to GB / T 9937 standard, the volume shrinkage of dental composite resin samples was analyzed using the American Proto-tech oral material polymerization stress measuring instrument.

[0072] Deformation height test: inject the sample into a metal mold with an outer diameter of 15mm, an inner diameter of 10mm, and a height of 10mm, and then use a resin filler to flatten the sample surface. The metal mold is fixed and stabilized with a clamp, such as Figure 1 As shown, a 304 stainless steel metal rod with a diameter of 2mm and a height of 50mm is clamped by a universal tensile testing machine. The sample is loaded at a tensile speed of 1mm / min at 25°C. When the stainless steel metal rod and the sample are completely separated, the tensile force of the universal tensile testing machine returns to zero, and the deformation displacement at this time is recorded as the deformation height. Repeat the test for five samples, and the average value is the sample deformation height.

[0073] E) Dental restoration paste resin was prepared as follows:

[0074] According to the composition ratio of Table 2, one or more polymerizable resin monomers are mixed with each other to prepare a resin matrix, and then under light-proof conditions, a certain ratio of photoinitiator, anti-aging agent, polymerization inhibitor, photoinitiator accelerator, etc. are added in sequence, heated to 60° C. and stirred to obtain a resin matrix composition; then, inorganic fillers, spherical porous silica powder, chain transfer agent and additives are dispersed in the resin matrix composition and stirred and mixed sufficiently, and finally grinded and dispersed by a three-roll grinder to obtain a paste resin for dental restoration. The component content of the paste resin is shown in Table 3, and the properties of the paste resin are tested, and the test results are shown in Table 4;

[0075] Table 2 Resin matrix composition data sheet

[0076]

[0077]

[0078] Table 3 Data table of the content of each component in the paste resin prepared in Example

[0079]

[0080] The test results of all embodiments are shown in Table 4;

[0081] Table 4 Performance data of the paste resin prepared in Example

[0082]

[0083] By comparing Example 1, Example 3 with Example 2, Example 4, it is shown that the addition of CTA chain transfer agent is beneficial to reducing the polymerization shrinkage rate of the paste resin, reducing the occurrence of secondary caries, and has no obvious effect on the mechanical properties of the resin; by comparing Example 1, Example 2 with Example 3, Example 4, it is shown that the addition of spherical porous silica gel powder can effectively reduce the viscosity of the paste resin to the instrument, and its deformation height is relatively low, which is beneficial to improving the clinical operation feel of the resin.

[0084] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0085] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A paste resin is prepared from the following raw materials: Additive residue; The resin matrix composition comprises a polymerized resin monomer, a reactive diluent, a photoinitiator, a photoinitiator accelerator, an inhibitor and an antioxidant. Based on the total amount of the resin matrix composition, the content of the polymerized resin monomer is 40-70wt%, the content of the reactive diluent is 20-50wt%, the content of the photoinitiator is 1-5wt%, the content of the photoinitiator accelerator is 1-5wt%, the content of the inhibitor is 0.3-1.0wt%, and the content of the antioxidant is 0.3-1.0wt%; The modified inorganic filler is composed of an inorganic particle filler modified by a silane coupling agent and an inorganic ultrafine particle modified by a silane coupling agent, and the mass ratio of the two is (2-20):1; The polymer resin monomer is selected from one or more of bisphenol A-dimethacrylate glycidyl, ethoxylated bisphenol A dimethacrylate, dimethacrylate urethane and aromatic dimethacrylate diisocyanate; the reactive diluent is selected from one or more of triethylene glycol dimethacrylate, 1,12-dodecanediol dimethacrylate and 1,6-hexanediol diacrylate; the photoinitiator is selected from camphorquinone, and the photoinitiator accelerator is selected from ethyl p-N,N-dimethylaminobenzoate; The additive includes titanium dioxide treated with a silane coupling agent, and the average particle size of the titanium dioxide is 50 to 80 nm; The chain transfer agent has a structure shown in formula (I); in, R is selected from S, carbonyl or phenyl; The preparation method of the porous spherical silica gel is specifically as follows: The aqueous silica sol is mixed with urea and formaldehyde, and copolymerized under acidic conditions to obtain a composite sphere; ashing the composite sphere at high temperature and then sintering at high temperature to obtain porous spherical silica gel; The inorganic particle filler is selected from one or more of glass powder, silicon dioxide, composite oxide particles, ceramics and zirconium oxide; The inorganic ultrafine particles are selected from one or more of aluminum oxide, zirconium oxide, hydroxyapatite, zinc oxide, calcium phosphate and ytterbium fluoride.

2. The paste resin according to claim 1, characterized in that The average particle size of the inorganic particle filler is 0.5-1.0 μm; the average particle size of the inorganic ultrafine particles is 0.05-0.2 μm.

3. The paste resin according to claim 1, characterized in that The porous spherical silica gel has an average particle size of 0.2 to 5 μm and a specific surface area of ​​1000 to 1500 m 2 / g.

4. The method for preparing the paste resin according to claim 1, comprising the following steps: Mixing polymer resin monomers, reactive diluents, photoinitiators, anti-aging agents, polymerization inhibitors and photoinitiator accelerators to obtain a resin matrix composition; The resin matrix composition, porous spherical silica gel, modified inorganic filler, chain transfer agent and additives are mixed to obtain a paste resin.

5. A dental restoration material, comprising a paste resin, wherein the paste resin is the paste resin according to any one of claims 1 to 3 or the paste resin prepared by the preparation method according to claim 4.

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