Dental acid etching agent, preparation method thereof and dentin surface treatment method

Abstract

The invention provides a dental acid etching agent, a preparation method thereof and a dentin surface treatment method. The dental acid etching agent comprises phosphoric acid and a functional resin monomer composition, on the basis of the dental acid etching agent, the functional resin monomer composition comprises 1-10 wt% of an acidic resin monomer and 1-5 wt% of an aldehyde group-containing resin monomer. The problem of nano leakage can be relieved, the durability and stability of bonding repair are improved, and the application prospect is wide.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dental materials, in particular to a dental etching agent, a preparation method thereof and a dentin surface treatment method. BACKGROUND

[0002] Resin-based materials have replaced traditional silver amalgam materials as the first choice for caries-related disease treatment due to their aesthetic and minimally invasive advantages. However, the long-term durability of resin-dentin bonding repair still faces severe challenges.

[0003] In clinical practice, regardless of the bonding strategy (full-etch system or self-etch system), etching leads to excessive exposure of collagen while providing the necessary structure for bonding, activating endogenous protease activity in dentin. However, resin materials cannot completely penetrate and encapsulate demineralized collagen, and the exposed collagen is gradually degraded by activated endogenous proteases, ultimately leading to the shedding of bonded restorations.

[0004] CN114010510B discloses a DMA-based dentin bonding pretreatment composition and its application. The dentin bonding pretreatment composition includes DMA, dimethyl sulfoxide, and a phosphoric acid solution. The above materials are mixed to obtain an etching agent. In the present application, DMA, as a bonding resin monomer, can penetrate synchronously with phosphoric acid in the etching agent, achieving integrated dentin etching demineralization and resin-based bonding medium penetration and filling. It can form polymerization with the bonding agent components through free radical polymerization, effectively improve the stability of dentin collagen structure, reduce the degradation risk caused by exogenous mechanical stress and biochemical factors of collagen, and reduce the enzymatic risk of the bonding interface. However, the phosphoric acid etching agent needs dimethyl sulfoxide to dissolve DMA, which is toxic.

[0005] CN118512333B discloses a mussel biomimetic monomer modified etching agent, its preparation method and application. The mussel biomimetic monomer modified etching agent provided in the present application can, on the basis of ensuring demineralization ability, well impart demineralized dentin with antibacterial activity, inhibit endogenous enzyme activity, and promote collagen crosslinking, achieving the purpose of improving the stability of the bonding interface and prolonging the service life of resin-dentin bonding, without the need for additional clinical operation steps. The main method in this method is to inhibit the degradation of dentin collagen by combining collagen fibers, without directly inhibiting enzyme activity.

[0006] Therefore, it is necessary to develop new dental etching agents to improve the immediate bonding strength and aged bonding strength after etching. SUMMARY

[0007] To solve the above technical problems, the present application provides a dental acid etching agent, a preparation method thereof and a dentin surface treatment method. By adding acid resin monomers and aldehyde group-containing resin monomers into the phosphoric acid etching agent, the collagen fibers are protected during the acid etching process, avoiding degradation by metalloproteinases, and enhancing the durability of adhesive repair. Meanwhile, the resin monomers can chemically react with the hydroxyapatite in the dentin to form stable phosphate ester bonds, improving the immediate bonding strength and the bonding strength after aging.

[0008] To achieve the above purpose, the present application adopts the following technical solutions:

[0009] In a first aspect, the present application provides a dental acid etching agent, which comprises phosphoric acid and a functional resin monomer composition; the functional resin monomer composition comprises 1-10 wt% of acid resin monomers and 1-5 wt% of aldehyde group-containing resin monomers, based on the dental acid etching agent.

[0010] The dental acid etching agent provided by the present application has the following special considerations:

[0011] Prevent collagen fiber degradation: by the binding ability of acid resin monomers to collagen fibers, the collagen fibers are protected during the acid etching process, avoiding degradation by metalloproteinases, and enhancing the durability of adhesive repair.

[0012] Inhibit metalloproteinase activity: the addition of aldehyde group-containing monomers such as formyl phenyl acrylate (FA) in the phosphoric acid etching system not only can covalently bind to collagen fibers, but also can bind to metalloproteinases (MMPs), further inhibiting the degradation of collagen fibers, effectively avoiding the nanoleakage problem caused by the degradation of collagen fibers, and further improving the durability and stability of adhesive repair.

[0013] In the present application, the acid resin monomers, aldehyde group-containing resin monomers and phosphoric acid synergistically cooperate with each other, which can further improve the immediate bonding strength after acid etching and the bonding strength after aging. In the present application, the phosphoric acid demineralizes the hydroxyapatite on the dentin surface, exposing the collagen fiber network, which provides the exposed amino group sites for the acid resin monomers and the aldehyde group-containing resin monomers; the acid resin monomers form hydrogen bonds and electrostatic attraction with the amino groups and hydroxyl groups of the collagen main chain, sealing the collagen fibers to avoid their degradation by metalloproteinases, enhancing the durability of adhesive repair, and at the same time, the acid resin monomers copolymerize with the resin matrix to improve the immediate bonding strength; the aldehyde group (-CHO of the aldehyde group-containing resin monomers binds to the Zn2 +The functional resin monomer composition can reversibly inhibit enzyme activity by coordinating or forming a Schiff base with lysine residues, block the collagen degradation pathway, improve the durability and stability of adhesive repair, and increase the immediate bonding strength by copolymerizing the aldehyde resin monomer with the resin matrix. If the acid resin monomer is the only component in the present application, it cannot inhibit the metalloproteinase pathway and reduce the risk of nanoleakage. If the aldehyde resin monomer is the only component in the present application, it cannot enhance the acid etching effect of dentin and further improve the durability and stability of adhesive repair.

[0014] Specifically, the functional resin monomer composition includes 1-10 wt% of acid resin monomer, which can be 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%, etc.

[0015] 1-5 wt% of aldehyde-containing resin monomer, which can be 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, or 5 wt%, etc.

[0016] When the proportion of acid resin monomer in the present application is less than 1 wt%, the dental acid etching agent cannot enhance the acid etching effect on dentin and inhibit collagen fiber degradation, thereby improving the bonding strength. When the proportion of acid resin monomer in the present application is greater than 10 wt%, it may cause excessive demineralization of dentin, excessive exposure of collagen fibers, and affect the bonding effect.

[0017] When the proportion of aldehyde resin monomer in the present application is less than 1 wt%, the dental acid etching agent cannot inhibit metalloproteinase activity and may still cause collagen degradation, affecting the stability of dentin bonding. When the proportion of aldehyde resin monomer in the present application is greater than 5 wt%, there may be certain toxicological risks, and it is not recommended for use.

[0018] Preferably, the mass percentage of phosphoric acid in the dental acid etching agent is 32-37 wt%, which can be 32 wt%, 32.6 wt%, 33.2 wt%, 33.7 wt%, 34.3 wt%, 34.8 wt%, 35.4 wt%, 35.9 wt%, 36.5 wt%, or 37 wt%, etc., but is not limited to the listed values. Other values not listed in this range are also applicable.

[0019] The preferred mass concentration of phosphoric acid in the present application is within the above range, which can improve the acid etching effect of teeth, achieve the required demineralization degree for bonding, improve the bonding effect, and alleviate the excessive acid etching of teeth, tooth sensitivity, and nanoleakage, etc.

[0020] Preferably, the mass concentration of the phosphoric acid is 34.3-35.4wt%, for example, it can be 34.3wt%, 34.5wt%, 34.6wt%, 34.8wt%, 34.9wt%, 35wt%, 35.1wt%, 35.2wt%, 35.3wt% or 35.4wt% and the like.

[0021] Preferably, the acidic resin monomer comprises any one of 10-methacryloyloxydecyl dihydrogen phosphate, 4-methacryloyloxyethyl trimethyl acid anhydride, pentaethyl phosphate, 2-acrylamido-2-methylpropane sulfonic acid, N-trimethylsiloxy-2-hydroxyethyl methacrylate, hexamethyl dihydrogen phosphate or ethyl acrylate phosphate or a combination of at least two thereof, wherein a typical but non-limiting combination is a combination of 10-methacryloyloxydecyl dihydrogen phosphate and 4-methacryloyloxyethyl trimethyl acid anhydride, a combination of pentaethyl phosphate and 4-methacryloyloxyethyl trimethyl acid anhydride, a combination of 10-methacryloyloxydecyl dihydrogen phosphate and pentaethyl phosphate, a combination of 2-acrylamido-2-methylpropane sulfonic acid and 4-methacryloyloxyethyl trimethyl acid anhydride, a combination of ethyl acrylate phosphate and N-trimethylsiloxy-2-hydroxyethyl methacrylate, preferably 10-methacryloyloxydecyl dihydrogen phosphate.

[0022] The present application preferably adopts 10-methacryloyloxydecyl dihydrogen phosphate, which has high stability, can chemically react with hydroxyapatite in dentin to form a stable phosphate ester bond, and in the presence of sufficient phosphate, this chemical reaction increases positively, further improving the acid etching effect on dentin, thereby improving the bonding strength. Compared with other monomers, it can more effectively seal collagen fibers and improve the bonding strength after aging.

[0023] Preferably, the aldehyde group-containing resin monomer comprises any one of formyl phenyl acrylate FA, vanillin methacrylate, acrylate-polyethylene glycol-aldehyde, 3-acryloyl-5-methyl vanillin, vanillin-based benzoxazine monomer, vinyl benzyl formamide or formamidyl acrylate monomer or a combination of at least two thereof, wherein a typical but non-limiting combination is a combination of formyl phenyl acrylate FA and vanillin methacrylate, a combination of acrylate-polyethylene glycol-aldehyde and vanillin methacrylate, a combination of formyl phenyl acrylate FA and 3-acryloyl-5-methyl vanillin, a combination of vanillin-based benzoxazine monomer and formamidyl acrylate monomer, a combination of formyl phenyl acrylate FA and vinyl benzyl formamide, preferably formyl phenyl acrylate FA.

[0024] The formyl phenyl acrylate FA is preferably adopted in the application, which can not only be covalently combined with collagen fibers, but also be combined with metalloproteinases (MMPs), further inhibiting the degradation of collagen fibers, effectively avoiding the problem of nano-leakage caused by the degradation of collagen fibers, and further improving the durability and stability of bonding repair. Compared with other monomers, the spatial structure and steric hindrance are more reasonable, and the binding capacity with MMPs is stronger. For example, the phenolic hydroxyl group of vanillin methacrylate and part of the aldehyde group form a six-membered intramolecular hydrogen bond, which is easy to cause the aldehyde group to be "locked" inside the molecule, increase the steric hindrance, weaken the binding capacity with MMPs, reduce the effect of inhibiting the degradation of collagen, and cause the effect of improving bonding durability to decrease.

[0025] Preferably, the dental etchant comprises a solvent.

[0026] Preferably, the solvent is water.

[0027] Preferably, the mass percentage content of the solvent is 38-65wt%, for example, it can be 38wt%, 41wt%, 44wt%, 47wt%, 50wt%, 53wt%, 56wt%, 59wt%, 62wt% or 65wt%, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0028] Preferably, the dental etchant further comprises an additive.

[0029] Preferably, the additive comprises a thickening agent and a pigment.

[0030] Preferably, the mass percentage content of the thickening agent is 1-10wt% based on the dental etchant, for example, it can be 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt% or 10wt%, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0031] Preferably, the mass percentage content of the pigment is 0.01-0.1wt% based on the dental etchant, for example, it can be 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.09wt% or 0.1wt%, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0032] Preferably, the thickening agent comprises any one or a combination of at least two of silica, xanthan gum, polyethylene glycol, glycerol, sodium carboxymethyl cellulose or carrageenan, wherein a typical but non-limiting combination is a combination of silica and xanthan gum, a combination of polyethylene glycol and xanthan gum, a combination of silica and polyethylene glycol, a combination of glycerol and xanthan gum, a combination of carrageenan and xanthan gum, a combination of carrageenan and sodium carboxymethyl cellulose.

[0033] Preferably, the pigment comprises any one or a combination of at least two of pigment brilliant blue, cobalt blue, indigo blue or methylene blue, wherein a typical but non-limiting combination is a combination of pigment brilliant blue and cobalt blue, a combination of indigo blue and cobalt blue, a combination of pigment brilliant blue and indigo blue, a combination of methylene blue and cobalt blue.

[0034] In a second aspect, the present application provides a method for preparing the dental etching agent of the first aspect, the method comprising: mixing raw materials of the dental etching agent, and subjecting to stirring and homogenization treatment to obtain the dental etching agent.

[0035] Preferably, the mixing of the raw materials of the dental etching agent comprises: sequentially adding a solvent, phosphoric acid, a functional resin monomer composition, a thickening agent after pretreatment and a pigment.

[0036] Preferably, the stirring speed is 300-700 rpm, for example, it can be 300 rpm, 345 rpm, 380 rpm, 430 rpm, 470 rpm, 520 rpm, 560 rpm, 610 rpm, 650 rpm or 700 rpm, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0037] Preferably, after adding each raw material, the stirring is stopped for 5-10 min to ensure that each raw material is fully dissolved before adding the next raw material.

[0038] Preferably, the stirring temperature is 20-30°C, for example, it can be 20°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C or 30°C, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0039] Preferably, the stirring time is 20-40 min, for example, it can be 20 min, 23 min, 25 min, 27 min, 29 min, 32 min, 34 min, 36 min, 38 min or 40 min, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0040] Preferably, the rotation speed of the homogenization treatment is 7000-9000 rpm, for example, it can be 7000 rpm, 7220 rpm, 7440 rpm, 7600 rpm, 7800 rpm, 8100 rpm, 8300 rpm, 8500 rpm, 8700 rpm, 9000 rpm, or the like, but is not limited to the listed values, and other values not listed in this range are also applicable.

[0041] Preferably, the time of the homogenization treatment is 15-25 min, for example, it can be 15 min, 17 min, 18 min, 19 min, 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, or the like, but is not limited to the listed values, and other values not listed in this range are also applicable.

[0042] Preferably, the pretreated thickening agent is a thickening agent after pretreatment.

[0043] Preferably, the pretreatment of the thickening agent comprises mixing water and the thickening agent, and performing a standing swelling treatment to obtain the pretreated thickening agent.

[0044] Preferably, the amount of water added in the pretreatment of the thickening agent is 10-20 wt% of the total amount of water in the dental etching agent, for example, it can be 10 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, or the like, but is not limited to the listed values, and other values not listed in this range are also applicable.

[0045] Preferably, the temperature of the standing swelling treatment is 35-45℃, for example, it can be 35℃, 37℃, 38℃, 39℃, 40℃, 41℃, 42℃, 43℃, 44℃, 45℃, or the like, but is not limited to the listed values, and other values not listed in this range are also applicable.

[0046] Preferably, the time of the standing swelling treatment is greater than 2 h, for example, it can be 2.1 h, 2.2 h, 2.3 h, 2.5 h, 2.8 h, 3.0 h, 3.2 h, 3.5 h, 3.8 h, 4.0 h, or the like, but is not limited to the listed values, and other values not listed in this range are also applicable.

[0047] Preferably, the phosphoric acid is a purified phosphoric acid.

[0048] Preferably, the purification treatment comprises removing impurities from the crude phosphoric acid by filtering through a microporous filter to obtain the purified phosphoric acid.

[0049] Preferably, the pore size of the microporous filter membrane is 0.2-0.3 μm, for example, it can be 0.2 μm, 0.22 μm, 0.23 μm, 0.24 μm, 0.25 μm, 0.26 μm, 0.27 μm, 0.28 μm, 0.29 μm or 0.3 μm, etc., but is not limited to the listed values, and other unlisted values within the range are also applicable.

[0050] In a third aspect, the present application provides a method for treating dentin surface, comprising the following steps: after the dentin is demineralized by a dental etching agent, an adhesive is applied. The dental etching agent comprises the dental etching agent of the first aspect and / or the dental etching agent prepared by the preparation method of the second aspect.

[0051] Compared with the prior art, the present application has at least the following beneficial effects:

[0052] (1) The dental etching agent provided by the present application can further enhance the etching effect on the basis of phosphoric acid etching, prevent collagen fiber degradation, inhibit metalloproteinase activity, and significantly improve the durability of resin-dentin bonding without the need for additional clinical operation steps;

[0053] (2) The dental etching agent provided by the present application has a bonding strength of ≥30 MPa immediately after treating dentin for 15 s, which is comparable to the effect of a commercial etching group; the aging bonding strength after treating dentin is significantly improved to ≥25 MPa;

[0054] (3) The dental etching agent provided by the present application has a bonding strength of dentin treated for 10 s, which is superior to the effect of 35% phosphoric acid etching for 15 s, including an immediate bonding strength of ≥30 MPa and an aging bonding strength of ≥20 MPa. DETAILED DESCRIPTION

[0055] In order to facilitate the understanding of the present application, the present application lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present application and should not be regarded as a specific limitation on the present application.

[0056] Nanoleakage problem exists in dental etching agent: collagen fibers are exposed after etching: after acid etching treatment, the collagen fibers in the dentin are exposed. Under the action of proteolytic enzymes (such as metalloproteinase MMPs), these exposed collagen fibers are prone to degradation, thereby producing nanoleakage. The direct cause comes from the acid etching treatment step: increasing the total acid etching treatment time will further increase the risk of nanoleakage. This is because the penetration depth of the adhesive usually cannot reach the depth of phosphoric acid demineralization, resulting in partial exposure of collagen fibers outside the bonding interface. In addition, the self-etching cement usually contains a large amount of hydrophilic monomers, which, after combining with water, are prone to form an environment that activates endogenous proteolytic enzymes, accelerates the hydrolysis of collagen fibers, and further leads to nanoleakage.

[0057] Some studies use metalloproteinase inhibitors (such as chlorhexidine, quaternary ammonium salt) or collagen cross-linking agents (such as glutaraldehyde) for irrigation to reduce the degradation of collagen fibers. However, these methods increase the complexity and steps of clinical operation, which is inconvenient for practical application. In addition, the study of adding enzyme inhibitor chlorhexidine to phosphoric acid for synchronous acid etching treatment shows that due to the presence of water in dentin, the enzyme inhibition effect of chlorhexidine will be weakened. In addition, chlorhexidine also has toxicity and drug resistance problems, which limits its wide application in clinic.

[0058] The present application solves the above technical problems by using an etching agent containing 1-10 wt% of acid resin monomer and 1-5 wt% of aldehyde group-containing resin monomer on the basis of phosphoric acid etching.

[0059] In the following examples and comparative examples, MDP: 10-methacryloyloxy decyl dihydrogen phosphate; 4-META: 4-methacryloyloxy ethyl trimethyl anhydride; FA: formyl phenyl acrylate; VMA: vanillyl methacrylate.

[0060] Example 1

[0061] The present example provides a dental etching agent, which comprises 35 wt% of phosphoric acid, 5 wt% of acid resin monomer (MDP), 3 wt% of aldehyde group-containing resin monomer (FA), 6 wt% of thickening agent (xanthan gum) and 0.05 wt% of pigment (brilliant blue), and the balance is water.

[0062] The present example also provides a preparation method of the dental etching agent, which comprises the following steps:

[0063] Purified phosphoric acid is obtained by filtering 85% food-grade phosphoric acid stock solution to remove impurities through a 0.22 μm microporous filter membrane;

[0064] The thickening agent is mixed with 15 wt% of purified water based on the total mass of water, and is subjected to swelling treatment at a temperature of 40°C for 2.5 h to obtain a pretreated thickening agent;

[0065] The phosphoric acid, MDP, FA, pretreated thickening agent and pigment are added to a reaction kettle in the following order: water→phosphoric acid→functional resin monomer combination (MDP)→pretreated thickening agent→pigment, with a stirring speed of 500 rpm, a temperature of 25°C and a total time of 30 min. Each addition of one material is followed by 6 min of stirring to ensure complete dissolution before adding the next material;

[0066] A high-shear homogenizer is used for homogenization treatment at 8000 rpm for 20 min to ensure complete dispersion, no clumping or uneven color, and to obtain a dental etching agent.

[0067] Example 2

[0068] The present embodiment provides a dental etching agent, which comprises 35 wt% of phosphoric acid, 6 wt% of acidic resin monomer (4-META), 2 wt% of aldehyde group-containing resin monomer (FA), 3 wt% of thickening agent (xanthan gum), and 0.05 wt% of pigment (brilliant blue), with the balance being water.

[0069] The present embodiment also provides a preparation method of the dental etching agent, which comprises the following steps:

[0070] Impurities are removed from the 85% food-grade phosphoric acid stock solution by filtering through a 0.22 μm microporous filter membrane to obtain purified phosphoric acid;

[0071] The thickening agent is mixed with 10 wt% of pure water based on the total mass of water, and is subjected to static swelling treatment at a temperature of 45°C for 2 h to obtain a pretreated thickening agent;

[0072] The phosphoric acid, MDP, FA, pretreated thickening agent, and pigment are added to a reaction kettle in the following order: water→phosphoric acid→functional resin monomer combination (MDP)→pretreated thickening agent→pigment, with a stirring speed of 700 rpm, a temperature of 20°C, and a total time of 20 min, and each addition of one material is followed by 5 min of stirring to ensure complete dissolution before adding the next material;

[0073] The high-shear homogenizer is used for homogenization treatment at 7000 rpm for 25 min to ensure complete dispersion without clumping or uneven color, thereby obtaining the dental etching agent.

[0074] Example 3

[0075] The present embodiment provides a dental etching agent, which comprises 35 wt% of phosphoric acid, 10 wt% of acidic resin monomer (MDP), 2 wt% of aldehyde group-containing resin monomer (VMA), 10 wt% of thickening agent (xanthan gum), and 0.05 wt% of pigment (brilliant blue), with the balance being water.

[0076] The present embodiment also provides a preparation method of the dental etching agent, which comprises the following steps:

[0077] Impurities are removed from the 85% food-grade phosphoric acid stock solution by filtering through a 0.22 μm microporous filter membrane to obtain purified phosphoric acid;

[0078] The thickening agent is mixed with 20 wt% of pure water based on the total mass of water, and is subjected to static swelling treatment at a temperature of 35°C for 2 h to obtain a pretreated thickening agent;

[0079] Phosphoric acid, MDP, FA, pretreated thickening agent, pigment are added into the reactor in the following order: water→ phosphoric acid→ functional resin monomer combination (MDP)→ pretreated thickening agent→ pigment, stirring speed 300 rpm, temperature 30℃, total time 40 min, interval stirring 5 min after adding each material to ensure complete dissolution before adding the next material;

[0080] High shear homogenizer is used for homogenization treatment at 9000 rpm for 15 min to ensure complete dispersion, no clumping or uneven color, to obtain the dental etching agent.

[0081] Example 4

[0082] The dental etching agent provided in this example comprises 35 wt% of phosphoric acid, 1 wt% of acidic resin monomer (MDP), 5 wt% of aldehyde group-containing resin monomer (FA), 1 wt% of thickening agent (xanthan gum), and 0.05 wt% of pigment (brilliant blue), with the balance being water.

[0083] The preparation method of the dental etching agent provided in this example comprises the following steps:

[0084] Purified phosphoric acid is obtained by filtering 85% food-grade phosphoric acid stock solution through a 0.22 μm microporous filter membrane to remove impurities;

[0085] The thickening agent is mixed with 15 wt% of purified water based on the total mass of water, and is subjected to static swelling treatment at a temperature of 40℃ for 3 h to obtain the pretreated thickening agent;

[0086] Phosphoric acid, MDP, FA, pretreated thickening agent, pigment are added into the reactor in the following order: water→ phosphoric acid→ functional resin monomer combination (MDP)→ pretreated thickening agent→ pigment, stirring speed 600 rpm, temperature 23℃, total time 35 min, interval stirring 8 min after adding each material to ensure complete dissolution before adding the next material;

[0087] High shear homogenizer is used for homogenization treatment at 7500 rpm for 20 min to ensure complete dispersion, no clumping or uneven color, to obtain the dental etching agent.

[0088] Example 5

[0089] The dental etching agent provided in this example comprises 35 wt% of phosphoric acid, 5 wt% of acidic resin monomer (MDP), 3 wt% of aldehyde group-containing resin monomer (FA), 3 wt% of thickening agent (silicon dioxide), and 0.05 wt% of pigment (brilliant blue), with the balance being water.

[0090] The preparation method of this example is the same as that of Example 1, which is not described again here.

[0091] Example 6

[0092] The present example provides a dental etching agent, which comprises 32wt% of phosphoric acid, 8wt% of acid resin monomer (MDP), 1wt% of aldehyde group containing resin monomer (FA), 5wt% of thickening agent (xanthan gum) and 0.1wt% of pigment (brilliant blue), with the balance being water.

[0093] The preparation method of the present example is the same as that of Example 1, which will not be repeated here.

[0094] Example 7

[0095] The present example provides a dental etching agent, which comprises 37wt% of phosphoric acid, 4wt% of acid resin monomer (MDP), 5wt% of aldehyde group containing resin monomer (FA), 2wt% of thickening agent (xanthan gum) and 0.03wt% of pigment (brilliant blue), with the balance being water.

[0096] The preparation method of the present example is the same as that of Example 1, which will not be repeated here.

[0097] Example 8

[0098] The present example provides a dental etching agent, which is the same as Example 1 except that MDP is replaced by pentaethyl phosphate, which will not be repeated here.

[0099] Example 9

[0100] The present example provides a dental etching agent, which is the same as Example 1 except that formyl phenyl acrylate FA is replaced by vanillin methacrylate, which will not be repeated here.

[0101] Example 10

[0102] The present example provides a dental etching agent, which is the same as Example 1 except that the concentration of phosphoric acid is 30wt%, which will not be repeated here.

[0103] Example 11

[0104] The present example provides a dental etching agent, which is the same as Example 1 except that the concentration of phosphoric acid is 40wt%, which will not be repeated here.

[0105] Comparative Example 1

[0106] The present comparative example provides a dental etching agent, which is the same as Example 1 except that MDP and FA are not added, which will not be repeated here.

[0107] Comparative Example 2

[0108] This comparative example provides a dental etching agent, which is the same as Example 1 except that the mass percentage content of MDP is only 0.5wt%, and details are not repeated here.

[0109] Comparative Example 3

[0110] This comparative example provides a dental etching agent, which is the same as Example 1 except that the mass percentage content of MDP is 11wt%, and details are not repeated here.

[0111] Comparative Example 4

[0112] This comparative example provides a dental etching agent, which is the same as Example 1 except that the mass percentage content of formyl phenyl acrylate FA is 0.5wt%, and details are not repeated here.

[0113] Comparative Example 5

[0114] This comparative example provides a dental etching agent, which is the same as Example 1 except that formyl phenyl acrylate FA is replaced by methyl methacrylate (MMA), and details are not repeated here.

[0115] Comparative Example 6

[0116] This comparative example provides a dental etching agent, which is the same as Example 1 except that MDP is replaced by urethane dimethacrylate (UDMA), and details are not repeated here.

[0117] Preparation of bonding test specimens: Select caries-free, crack-free extracted third molars, and grind the occlusal enamel perpendicular to the long axis of the tooth under water cooling with a low-speed diamond saw (Isomet type), exposing a flat dentin surface. Wet sandpaper with 600 mesh silicon carbide sandpaper for 1 minute, ultrasonic cleaning for 30 seconds to remove the smear layer, use each group of etching agent to demineralize the crown dentin, deionized water rinse for 30s, filter paper to absorb surface moisture, apply adhesive (3M Single Bond Universal) for 10s, blow for 5s, and cure for 20s. After preparation, the test specimens are immersed in 37℃ deionized water for 24h for the immediate group, and subjected to 10000 cycles of cold and hot cycles (5-55℃, temperature changed every 30s) for the simulated oral 1-year aging group.

[0118] Microtensile test: Then, the immediate group and the aging group samples were embedded in epoxy resin, and longitudinal sections were made along the bonding interface in the middle, distal and buccal-lingual directions of the specimens using a slow cutting machine to obtain (1x1x6mm) standard resin-dentin strip bonding test specimens with a cross-sectional area of 1mm 2The dentin strips were fixed on the microtensile test mold with cyanoacrylate glue, and the microtensile strength test was performed by applying tension at a tensile speed of 1 mm / min with a universal mechanical testing machine (n = 10, i.e. 10 samples per group). At the end of the test, the cross-sectional area at the fracture interface of the sample was measured and calculated with a digital micrometer, and the microtensile strength (MPa) was calculated according to the following formula: microtensile strength (MPa) = maximum load at fracture point (N) / cross-sectional area at fracture point (mm 2 ).

[0119] For comparative analysis, the above dental etching agents were used to etch dentin for 15 s, and immediate and aged bonding strength tests were performed. The test results of the above examples and comparative examples are shown in Table 1.

[0120] Table 1

[0121] Instantaneous bond strength / MPa Aged bond strength / MPa Example 1 32.37 27.46 Example 2 31.02 26.11 Example 3 31.67 26.57 Example 4 31.32 26.37 Example 5 31.92 26.71 Example 6 30.98 26.03 Example 7 31.06 26.16 Example 8 30.61 25.61 Example 9 30.77 25.59 Example 10 29.32 24.63 Example 11 29.78 24.90 Comparative Example 1 27.32 18.97 Comparative Example 2 28.61 20.36 Comparative Example 3 28.56 20.21 Comparative Example 4 28.62 20.27 Comparative Example 5 27.89 19.39 Comparative Example 6 27.78 19.61

[0122] From Table 1, it can be seen that:

[0123] (1) As can be seen from Examples 1-7, the dental etching agent provided by the present application has both immediate bonding strength and aged bonding strength after etching dentin for 15 s, wherein the immediate bonding strength is above 30.98 MPa, and the aged bonding strength is above 26.03 MPa.

[0124] (2) As can be seen from Comparative Example 1 and Examples 8-9, the present application preferably uses a combination of MDP and FA, which synergize with each other to better improve the immediate bonding strength and aged bonding strength after treatment; specifically, the chemical stability of pentaethyl phosphate is relatively weak compared to MDP, and its effect on long-term sealing of collagen fibers is weaker than that of MDP, resulting in a decrease in the effect of long-term inhibition of collagen degradation and a decrease in the effect of improving bonding durability; the phenolic hydroxyl group of vanillin methacrylate forms a six-membered intramolecular hydrogen bond with part of the aldehyde group, causing the aldehyde group to be "locked" inside the molecule, increasing steric hindrance and weakening the binding ability with MMPs, reducing the effect of inhibiting collagen degradation, and reducing the effect of improving bonding durability.

[0125] (3) As can be seen from Comparative Example 1 and Examples 10-11, the present application preferably controls the concentration of phosphoric acid within a reasonable range, which cooperates with the resin monomer to significantly improve the bonding performance and aged bonding strength.

[0126] (4)Comparative Examples 8-11 and Comparative Examples 1-6 can be seen that the instant bonding strength and aging bonding strength of Examples 8-11 are superior to the latter, the bonding performance is significantly improved, the dentin bonding instant bonding strength is ≥30MPa, the aging bonding strength is ≥25MPa; thus indicating that the combination of 1-10wt% of the acid resin monomer and 1-5wt% of the aldehyde group-containing resin monomer selected by the present application can significantly improve the bonding performance and the aging bonding performance.

[0127] In order to embody the acid etching time of the dental acid etching agent provided by the present application can be shortened, the dental acid etching agent of Example 1 and Example 2 is used to etch the dentin for 10s, and the instant bonding strength and aging bonding strength after acid etching are compared with the acid etching time of 15s in Comparative Example 1, and the results are shown in Table 2.

[0128] Table 2

[0129] Etching time Instantaneous bond strength / MPa Aged bond strength / MPa Comparative Example 1 15s 27.32 18.97 Example 1 10s 30.41 21.39 Example 2 10s 30.36 20.71

[0130] From Table 2, it can be seen that the acid etching time of the dental acid etching agent provided by the present application can be shortened by 1 / 3 compared with Comparative Example 1, and can have better technical effects than Comparative Example 1.

[0131] The present application is described by the above examples to illustrate the detailed features of the present application, but the present application is not limited to the above detailed features, that is, it does not mean that the present application must rely on the above detailed features to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of the technical features selected by the present application, addition of auxiliary technical features, selection of specific modes, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. A dental etching agent, characterized in that, The dental etching agent comprises a composition of phosphoric acid and functional resin monomers; Based on dental etching agents, the functional resin monomer composition comprises 1 to 10 wt% of acidic resin monomers and 1 to 5 wt% of aldehyde-containing resin monomers.

2. The dental etching agent according to claim 1, characterized in that, The phosphoric acid content, based on the dental etching agent, is 32-37 wt% by mass.

3. The dental etching agent according to claim 1 or 2, characterized in that, The acidic resin monomer includes any one or a combination of at least two of the following: 10-methacryloyloxydecyl dihydrophosphate, 4-methacryloyloxyethyltrimethyl anhydride, pentaethyl phosphate, 2-acrylamide-2-methylpropanesulfonic acid, N-trimethylsiloxy-2-hydroxyethyl methacrylate, hexamethyl dihydrophosphate, or ethyl acrylate phosphate, preferably 10-methacryloyloxydecyl dihydrophosphate.

4. The dental etching agent according to any one of claims 1 to 3, characterized in that, The aldehyde-containing resin monomer includes any one or a combination of at least two of the following: formyl phenyl acrylate FA, vanillin methacrylate, acrylate-polyethylene glycol-aldehyde, 3-acryloyl-5-methylvanillin, vanillin-benzoxazine monomer, vinyl benzylformamide, or formamidoacrylate monomer, preferably formyl phenyl acrylate FA.

5. The dental etching agent according to any one of claims 1 to 4, characterized in that, The dental etching agent includes a solvent; Preferably, the solvent is water; Preferably, the solvent has a mass percentage of 38-65 wt% based on the dental etching agent.

6. The dental etching agent according to any one of claims 1 to 5, characterized in that, The dental etching agent also includes additives; Preferably, the additives include thickeners and colorants; Preferably, the thickener has a mass percentage of 1 to 10 wt% based on the dental etching agent; Preferably, the pigment has a mass percentage content of 0.01 to 0.1 wt% based on the dental etching agent; Preferably, the thickener comprises any one or a combination of at least two of the following: silica, xanthan gum, polyethylene glycol, glycerol, sodium carboxymethyl cellulose, or carrageenan. Preferably, the pigment includes any one or a combination of at least two of the following: Brilliant Blue, Cobalt Blue, Indigo Blue, or Methylene Blue.

7. A method for preparing a dental etching agent according to any one of claims 1 to 6, characterized in that, The preparation method includes: The raw materials for the dental etching agent are mixed and then stirred and homogenized to obtain the dental etching agent.

8. The preparation method according to claim 7, characterized in that, The raw materials for the mixed dental etching agent include: solvent, phosphoric acid, functional resin monomer composition, pretreated thickener and pigment added in sequence; Preferably, the stirring speed is 300–700 rpm; Preferably, the stirring temperature is 20–30°C; Preferably, the stirring time is 20–40 min; Preferably, the rotation speed of the homogenization process is 7000-9000 rpm; Preferably, the homogenization process takes 15 to 25 minutes.

9. The preparation method according to claim 7 or 8, characterized in that, The pretreated thickener is a pretreated thickener; Preferably, the pretreatment of the thickener includes: mixing water and thickener, and performing a static swelling treatment to obtain a pretreated thickener; Preferably, the amount of water added during the pretreatment of the thickener is 10-20 wt% of the total water content in the dental etching agent; Preferably, the temperature of the static swelling treatment is 35–45°C; Preferably, the static swelling treatment time is greater than 2 hours; Preferably, the phosphoric acid is purified phosphoric acid; Preferably, the purification process includes: filtering crude phosphoric acid through a microporous membrane to remove impurities, thereby obtaining purified phosphoric acid; Preferably, the pore size of the microporous filter membrane is 0.2 to 0.3 μm.

10. A method for dentin surface treatment, characterized in that, Includes the following steps: After demineralizing dentin with a dental etching agent, an adhesive is applied; the dental etching agent includes the dental etching agent according to any one of claims 1 to 6 and / or the dental etching agent prepared by the preparation method of the dental etching agent according to any one of claims 7 to 9.