Preparation method of high-strength fluoride salt with fluoride ion releasing ability and its application in 3D printing orthodontic appliances

Abstract

The present invention discloses a preparation method of a high-strength fluoride salt with fluoride ion-releasing ability and its application in 3D-printed orthodontic appliances. The high-strength fluoride salt has four benzyl groups and at least one polymerizable reactive group, and contains a tetrafluoroboric acid structure. The tetrabenzyl structure provides extremely high strength for the 3D-printed appliance, the acrylate structure provides good long-term stability for the 3D-printed appliance, and the tetrafluoroboric acid structure provides excellent fluoride ion-releasing ability for the 3D-printed appliance. It can also avoid dissolution during the treatment cycle that affects the product surface, and can improve the surface smoothness, thereby having significant application prospects.

Description

Technical Field

[0001] The present invention relates to the field of 3D printing technology, and more specifically, to a method for preparing a high-strength fluoride salt with fluoride ion-releasing ability and its application in 3D printing of orthodontic appliances. Background Art

[0002] In recent years, 3D printing technology has achieved rapid development, especially in the field of orthodontics. The emergence of 3D printing technology has solved the problems of long preparation cycle, low efficiency and high cost of traditional orthodontic dental molds, and promoted the rapid growth of the orthodontic industry market. Although 3D printing orthodontic dental molds is currently the mainstream technology, as an intermediate model material for the molding of customized braces, some problems are inevitable, especially the deformation of the dental mold during the molding process, the high failure rate during the tedious process of printing, cleaning and curing, and the troublesome process of demolding the braces. Compared with the complex operation of 3D printing dental molds and then using diaphragms for molding to obtain braces, directly 3D printing braces is undoubtedly one of the efficient and simple technical solutions, and it is also one of the hot research and development directions of the current technology.

[0003] Traditional braces are derived from orthodontic diaphragms, which are typically made of common plastic materials such as thermoplastic polyurethane (TPU), alcohol-modified polyethylene terephthalate (PETG), typically polyethylene terephthalate (PET), polypropylene (PP), and polycarbonate (PC). Wearing braces alters the relationship between teeth, and the braces block toothbrush bristles, making cleaning more difficult. This leads to accumulation of food debris and an imbalance in the oral flora. The closed environment created by braces reduces saliva production around the teeth, hindering their self-cleaning properties. It also reduces calcium and phosphate ion levels, weakening remineralization efficiency and causing orthodontic white spots. White spot lesions (WSLs) are white spots that appear on the tooth surface and are a sign of decalcification or demineralization of tooth enamel. Caries produced after orthodontic treatment not only affects the appearance, but may also develop into severe caries, leading to the destruction of multiple tooth tissues and affecting the efficiency of tooth movement. It is a post-orthodontic complication worthy of attention.

[0004] Currently, there is little concern about orthodontic white spots when it comes to 3D printed braces materials. Fluoride can reduce the solubility of tooth enamel and promote enamel remineralization. At the same acidity, if fluoride is present, the solubility of teeth is reduced, making caries less likely to occur. After minor caries occur, exposure to fluoride can reverse the caries to a certain extent. Fluoride can inhibit the growth of cariogenic bacteria in the mouth and inhibit bacterial acid production. Cariogenic bacteria decompose food residues to produce acid, which dissolves minerals in the teeth to form caries. Fluoride has an inhibitory effect on this process. Conventional diaphragms and braces have been improved through coatings and fluorides. However, since the fluoride additive is non-reactive, it will dissolve during the treatment cycle, causing surface defects. As a result, some tiny residues will remain in the defects, which will increase the risk of uneven tooth color and tooth decay. Therefore, the fluoride-containing composition should have good reactivity with 3D printing materials to increase the good chemical bonding force with the 3D printed braces, ensuring that it does not dissolve during the treatment process, which has a positive effect on biological rejection and treatment effect.

[0005] In orthodontic treatment, due to the long treatment cycle, the dimensional stability of the appliance during the treatment cycle is crucial to the final treatment effect. Therefore, the requirement for 3D printed appliance materials to not deform is relatively strict. Therefore, maintaining high printing strength during the printing process and the treatment process is a problem that needs to be solved. In summary, adding a composition that can effectively improve the occurrence of orthodontic white spots to the 3D printed appliance material is of great significance for the treatment effect of orthodontic treatment. It should have the following three characteristics:

[0006] 1. High strength, maintaining a basically unchanged shape retention rate during use.

[0007] 2. Highly efficient fluoride ion release ability. Effectively improve orthodontic white spots caused by tooth demineralization.

[0008] 3. It has reactive groups that react with 3D printing materials, maintains a good bonding force with the 3D printing materials, and does not dissolve during the treatment cycle, thereby affecting the surface of the orthodontic appliance. Summary of the Invention

[0009] In view of this, the present invention provides a method for preparing a high-strength fluoride salt with fluoride ion release ability to meet high-strength and high-efficiency fluoride ion release performance, so as to be used for preparing 3D printed orthodontic appliance materials to meet the therapeutic effect.

[0010] The technical solutions of the present invention are as follows:

[0011] The first aspect of the present invention is to provide a high-strength fluoride salt with fluoride ion release capability, having the structural formula shown in Formula I:

[0012]

[0013] Where R is C n H 2n , 1≤n≤3.

[0014] The second aspect of the present invention is to provide a method for preparing the high-strength fluoride salt described in the first aspect, comprising the following steps:

[0015] S1. reacting tribenzylamine with a halide to obtain intermediate 1;

[0016] S2. The obtained intermediate is reacted with an acrylic resin monomer under the action of an inhibitor to obtain an intermediate II;

[0017] S3. The intermediate 2 is reacted with tetrafluoroboric acid at reflux temperature of 50-150°C for 4-24 hours to obtain a high-strength fluoride salt having the ability to release fluoride ions;

[0018] The halide has a structure shown in Formula II:

[0019]

[0020] Where R is C n H 2n , 1≤n≤3; X is a halogen.

[0021] Furthermore, in step S1, the halide is selected from one of 2-(2-(chloromethyl)phenyl)oxirane, 2-(3-(chloromethyl)phenyl)oxirane, 2-(4-(chloromethyl)phenyl)oxirane, 2-(4-(bromomethyl)phenyl)oxirane, 2-(3-(bromomethyl)benzyl)oxirane, 2-(4-(bromomethyl)benzyl)oxirane, and 2-(2-(chloromethyl)phenethyl)oxirane.

[0022] Furthermore, the molar ratio of tribenzylamine to halide is 1:(1-3); preferably 1:(1-1.5).

[0023] Furthermore, the solvent used in steps S1 to S3 is selected from one or more of hot ethanol, ether, chloroform, benzene, toluene, xylene, ether, dichloromethane, chloroform, acetate, 1,2-dichloroethane, 1,4-dioxane, tetrahydrofuran, acetone, butanone, cyclohexanone or N,N-dimethylformamide.

[0024] Furthermore, in step S2, the polymerization inhibitor is selected from one or more of hydroquinone and its derivatives (2,5-di-tert-butylhydroquinone, 2-tert-butylhydroquinone), p-benzoquinone, methylhydroquinone, and p-hydroxyanisole;

[0025] And / or, the molar ratio of the intermediate 1 to the acrylic resin is 1:(1-3); preferably 1:(1-1.25).

[0026] Furthermore, in step S3, the molar ratio of the intermediate II to tetrafluoroboric acid is 1:(1-2.5).

[0027] The third aspect of the present invention is to propose the use of the high-strength fluoride salt described in the first aspect or the high-strength fluoride salt obtained by the preparation method described in the second aspect in the preparation of 3D printed orthodontic appliances.

[0028] Furthermore, the mass fraction of the high-strength fluoride salt added to the 3D printing material is 0.1-20%.

[0029] The fourth aspect of the present invention is to propose a 3D printing resin composition, which includes, by weight percentage: 0.1-20% of a monomer having a fluorine-releasing function, 80-99% of a photocurable monomer, and 1-3% of a photoinitiator; the monomer having a fluorine-releasing function is the high-strength fluoride salt described in the first aspect or the high-strength fluoride salt obtained by the preparation method described in the second aspect.

[0030] The fifth aspect of the present invention is to provide a 3D printed orthodontic appliance, which is obtained by 3D printing and curing the 3D printing resin composition described in the fourth aspect.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The high-strength fluoride salt of the present invention has four benzyl groups and at least one polymerizable reactive group, as well as a tetrafluoroboric acid structure. The tetrabenzyl structure provides extremely high strength for the 3D printed appliance, the acrylate structure provides good long-term stability for the 3D printed appliance, and the tetrafluoroboric acid structure provides the 3D printed appliance with excellent fluoride ion release ability, which can effectively improve orthodontic white spots caused by tooth demineralization.

[0033] The high-strength fluoride salt described in this invention maintains excellent bonding strength when used in 3D printing materials. It can also be used in orthodontic appliances to prevent dissolution during the treatment cycle, which could affect the product surface. While releasing fluoride ions, it can also improve surface smoothness, demonstrating significant application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of a dental mold sample of an orthodontic appliance obtained by 3D printing in one embodiment of the present invention. DETAILED DESCRIPTION

[0035] The following are specific implementation examples of the present invention, which are preferred and detailed descriptions of the present invention. It should be understood that the specific implementation methods described in this specification are only for explaining the present invention and are not intended to limit the present invention.

[0036] In one embodiment, a method for preparing a high-strength fluoride salt having the ability to release fluoride ions is provided, wherein the fluoride salt has the structural formula shown in Formula I:

[0037]

[0038] Where R is C n H 2n , n is a natural number and 1≤n≤3.

[0039] Contains four benzyl groups and at least one polymerizable reactive group, and contains a tetrafluoroboric acid structure. Specifically, the preparation method of the high-strength fluoride salt with fluoride ion release ability is as follows:

[0040] 1. Use tribenzylamine to react with halide, the general chemical formula of halide is C 9+a H 9+2a XO (a is 0-2), the halide is characterized by containing an epoxy group, a benzene ring structure and a halogen substituent. The molar ratio of tribenzylamine to the halide is 1:3, wherein the preferred ratio is 1:1-1:1.15 to ensure the purity of the product.

[0041] Wherein X is a halogen selected from I, Br or Cl; preferably Br or Cl. Preferred halides include 2-(2-(chloromethyl)phenyl)oxirane, 2-(3-(chloromethyl)phenyl)oxirane, 2-(4-(chloromethyl)phenyl)oxirane, 2-(4-(bromomethyl)phenyl)oxirane, 2-(3-(bromomethyl)benzyl)oxirane, 2-(4-(bromomethyl)benzyl)oxirane, and 2-(2-(chloromethyl)phenethyl)oxirane.

[0042] Tribenzylamine was dissolved in a solvent (1 mol of tribenzylamine per 1 kg of solvent). The reactants were stirred and refluxed at 80-180°C for 6-48 hours. After washing twice with solvent, excess reactants were removed using a rotary evaporator at 200 rpm in an 80°C water bath to obtain intermediate product N1.

[0043] 2. The above-mentioned N1 is dissolved in a solvent containing 1% polymerization inhibitor (1 kg of solvent dissolves 1 mol of N1 substance), and an acrylic resin monomer is added. The oxygen-containing heterocyclic ring opens and reacts with acrylic acid to form a reactive acrylate. The monomer containing an acrylic acid structure can be acrylic acid or methacrylic acid. After the reaction is stirred and refluxed, the excess solvent is removed by rotary evaporation to obtain product N2. The molar ratio of N1 to (meth)acrylic resin is 1:1-1:3. To ensure product purity, the preferred molar ratio is 1:1-1:1.25. The polymerization inhibitor is a mixture of one or more of hydroquinone and its derivatives (2,5-di-tert-butylhydroquinone, 2-tert-butylhydroquinone), p-benzoquinone, methylhydroquinone, and p-hydroxyanisole.

[0044] 3. Dissolve the nitrogen in a solvent (1 kg of solvent dissolves 1 mol of nitrogen) and add tetrafluoroboric acid. Stir and reflux at 50°C-150°C for 4-24 hours, then remove excess solvent by rotary evaporation. The final product is obtained in a molar ratio of nitrogen to tetrafluoroboric acid of 1:1-1:2.5.

[0045] The solvent may be one or more mixtures of hot ethanol, ether, chloroform, benzene, toluene, xylene, ether, dichloromethane, chloroform, acetate, 1,2-dichloroethane, 1,4-dioxane, tetrahydrofuran, acetone, butanone, cyclohexanone or N,N-dimethylformamide.

[0046] In the above embodiments, the tetrabenzyl structure contained in the high-strength fluoride salt with fluoride ion releasing ability provides extremely high strength for the 3D printed appliance, the acrylate structure provides good long-term stability for the 3D printed appliance, and the tetrafluoroboric acid structure provides excellent fluoride ion releasing ability for the 3D printed appliance.

[0047] In the above embodiment, taking the reaction of 2-[4-(chloromethyl)phenyl]oxirane and tribenzylamine as an example, the specific synthesis route is as follows:

[0048]

[0049] In another embodiment, the high-strength fluoride salt with fluoride ion-releasing ability described in the above embodiment is used in the field of 3D-printed orthodontic appliances, specifically by preparing a 3D printing composition, then 3D printing and light-curing the composition. Specifically, the content of each component of the 3D printing composition is within the following range:

[0050] (a) 0.1-20% by weight of high-strength fluoride salt

[0051] (b) 80-99% by weight of photocurable monomer

[0052] (c) 1-3% by weight of photoinitiator

[0053] Since the prepared material is a universal functional material for 3D printing orthodontic appliances, aliphatic acrylate and 4-acryloylmorpholine are used as typical monomer pairs to evaluate the material performance. Other available monomers are not limited. The specific examples are evaluated using the following ratios:

[0054] (a) 0.1%-20% by weight of high-strength fluoride salt

[0055] (b) 80-99% by weight of aliphatic polyurethane acrylate 50%, 4-acryloylmorpholine 40%

[0056] (c) 1-3% by weight of initiator

[0057] It is understood that the addition amount of the high-strength fluoride salt required for preparing 3D-printed orthodontic appliances in the aforementioned 3D printing composition can be selected within a range of 0.1%-20%, depending on the desired material properties. A higher addition amount improves both fluoride ion release and 3D print strength. Therefore, considering fluoride ion release and 3D print strength, a range of 2-20% can be selected, preferably 5-20%, and more preferably 5-15%.

[0058] In the above examples, the aliphatic polyurethane acrylate can be obtained from manufacturers such as Sartomer and Changxing. In this experiment, Sartomer CN8000 was used, and 4-acryloylmorpholine was purchased from Merck Chemicals.

[0059] The polymerization inhibitor used is one or more mixtures of hydroquinone and its derivatives (2,5-di-tert-butylhydroquinone, 2-tert-butylhydroquinone), p-benzoquinone, methylhydroquinone and p-hydroxyanisole.

[0060] In the above embodiment, the photoinitiator used in the photosensitive resin is one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide or a mixture thereof; the above inhibitors and photoinitiators are common raw materials and are purchased from McLean.

[0061] Specifically, in a preferred embodiment, the 3D printing process involves pouring the photosensitive resin composition into the resin tank of a 3D printing DLP device and performing printing with printing parameters of 300mW and a single-layer curing time of 2.1s. A 100mm*12mm*2mm mechanical test strip (universal mechanical testing machine) and a 10mm diameter, 1mm thick disc were printed to test fluorine release, and a 50mm diameter, 10mm thick disc was printed to test surface roughness.

[0062] In one embodiment, the above-mentioned photosensitive resin composition is 3D printed into a brace sample such as Figure 1 shown.

[0063] The following are preferred implementation examples. Where the manufacturer of the reagents or instruments is not indicated in the examples, conventional products can be purchased from the market. Where specific conditions are not indicated, conventional conditions or conditions recommended by the manufacturer can be followed.

[0064] Example 1

[0065] 1. Add 28.7g (0.1mol) of tribenzylamine to a stirring reflux flask and dissolve it in 100g of methyl ether, then add 16.8g (0.1mol) of 2-(2-(chloromethyl)phenyl)ethylene oxide, set the temperature to 80°C, and after 6h, pour the product into a rotary evaporation flask to remove excess reactants, then add xylene, wash twice, and continue to use rotary evaporation to remove excess solvent to obtain 37.4g of white crystalline product.

[0066] 2. Take 22.8g (0.05mol) of the above white crystals and dissolve them in 50g of acetone (containing 1% hydroquinone) in a reflux stirring device under 80℃ water bath conditions. Slowly add 3.6g (0.05mol) of acrylic acid dropwise. Sampling and testing are carried out until the epoxy group reaches 1120cm -1 The infrared peak of the band disappeared. The excess acrylic acid and solvent were removed by rotary evaporation to obtain 25.8 g of white crystals.

[0067] 3. Dissolve 20.6 g (0.04 mol) of the above product in 40 g of 1,2-dichloroethane, add 3.5 g (0.04 mol) of tetrafluoroboric acid, and react at 70°C in a stirring reflux flask for 4 h. Transfer to a rotary evaporator to remove excess solvent to obtain the final product.

[0068] 4. Prepare a 3D printing resin composition according to the following proportions: 5% (10 g) of the above product, 50% (100 g) of aliphatic acrylate, 42% (84 g) of 4-acryloylmorpholine, and 3% (6 g) of initiator, and stir at 2000 rpm in a high-speed disperser for 2 min.

[0069] Example 2

[0070] 1. Add 28.7g (0.1mol) of tribenzylamine to a stirring reflux flask and dissolve it in 100g of methyl ether, then add 23.6g (0.14mol) of 2-(3-(chloromethyl)phenyl)ethylene oxide, set the temperature to 180°C, and after 48h, pour the product into a rotary evaporation flask to remove excess reactants, then add solvent, wash twice, and continue to use rotary evaporation to remove excess solvent to obtain 45.2g of white crystalline product.

[0071] 2. Take 22.8g (0.05mol) of the above white crystals and dissolve them in 50g of cyclohexanone (containing 1% hydroquinone) in a reflux stirring device under 80°C water bath conditions. Slowly add 5.4g (0.0625mol) of methacrylic acid dropwise. Sampling and testing are carried out until the epoxy group reaches 1120cm -1 The infrared peak of the band disappeared. The excess methacrylic acid and solvent were removed by rotary evaporation to obtain 25.1 g of white crystals.

[0072] 3. 21.7 g (0.04 mol) of the above product was dissolved in 40 g of tetrahydrofuran, and 3.5 g (0.04 mol) of tetrafluoroboric acid was added. The mixture was stirred at 150°C in a reflux flask for 24 h. The mixture was transferred to a rotary evaporator to remove excess solvent to obtain the final product.

[0073] 4. Prepare a 3D printing resin composition according to the following proportions: 5% (10 g) of the above product, 50% (100 g) of aliphatic acrylate, 42% (84 g) of 4-acryloylmorpholine, and 3% (6 g) of initiator, and stir at 2000 rpm in a high-speed disperser for 2 min.

[0074] Example 3

[0075] 1. Add 57.4g (0.2mol) of tribenzylamine to the stirring reflux flask and dissolve it in 100g of chloroform, then add 100.8g of 2-(4-(chloromethyl)phenyl)ethylene oxide, set the temperature to 120°C, after 12h, set the speed to 200r / min, pour the product into a rotary evaporation flask, remove excess reactants, then add solvent, wash twice, continue to use rotary evaporation to remove excess solvent, and obtain 80.4g of white crystalline product.

[0076] 2. Take 45.6g (0.1mol) of the above white crystals and dissolve them in 100g of N,N-dimethylformamide (containing 1% hydroquinone) in a reflux stirring device under 80℃ water bath conditions. Slowly add 7.2g (0.1mol) of acrylic acid dropwise and take samples for testing until the epoxy group reaches 1120cm -1 The infrared peak disappeared, and the excess methacrylic acid and solvent were removed by rotary evaporation to obtain 48.4 g of white crystals.

[0077] 3. 43.4 g (0.08 mol) of the above product was dissolved in 80 g of ethanol, and 7 g (0.08 mol) of tetrafluoroboric acid was added. The mixture was stirred at 90°C in a reflux flask for 12 h, and then transferred to a rotary evaporator to remove excess solvent to obtain the final product.

[0078] 4. Prepare a 3D printing resin composition according to the following proportions: 20% (40 g) of the above product, 35% (70 g) of aliphatic acrylate, 42% (84 g) of 4-acryloylmorpholine, and 3% (6 g) of initiator, and stir at 2000 rpm in a high-speed disperser for 2 minutes.

[0079] Example 4

[0080] 1. Add 28.7g (0.1mol) of tribenzylamine to a stirring reflux flask and dissolve it in 100g of butanone, then add 33.3g (0.1mol) of 2-(4-(bromomethyl)phenyl)ethylene oxide. Set the temperature to 120°C. After 12h, pour the product into a rotary evaporation flask to remove excess reactants, then add solvent, wash twice, and continue to use rotary evaporation to remove excess solvent to obtain 50.9g of white crystalline product.

[0081] 2. Take 25g (0.05mol) of the above white crystals and dissolve them in 50g of acetone (containing 1% hydroquinone) in a reflux stirring device under 80℃ water bath conditions. Slowly add 10.8g (0.15mol) of acrylic acid dropwise. Sampling and testing are carried out until the epoxy group reaches 1120cm -1 The infrared peak disappeared, and the excess methacrylic acid and solvent were removed by rotary evaporation to obtain 27.8 g of white crystals.

[0082] 3. 22.3 g (0.04 mol) of the above product was dissolved in 40 g of ethyl acetate, and 4.4 g (0.05 mol) of tetrafluoroboric acid was added. The mixture was stirred at 50°C in a reflux flask for 4 h, and then transferred to a rotary evaporator to remove excess solvent to obtain the final product.

[0083] 4. Prepare a 3D printing resin composition according to the following proportions: 2% (4 g) of the above product, 53% (106 g) of aliphatic acrylate, 42% (84 g) of 4-acryloylmorpholine, and 3% (6 g) of initiator, and stir at 2000 rpm in a high-speed disperser for 2 min.

[0084] Example 5

[0085] 1. Add 57.4g (0.2mol) of tribenzylamine to a stirring reflux flask and dissolve it in 200g of butanone, then add 42g (0.23mol) of 2-(2-(chloromethyl)phenethyl)ethylene oxide. Set the temperature to 100°C. After 6h, pour the product into a rotary evaporation flask to remove excess reactants, then add solvent, wash twice, and continue to use rotary evaporation to remove excess solvent to obtain 77g of white crystalline product.

[0086] 2. Take 47g (0.1mol) of the above white crystals and dissolve them in 100g of toluene (containing 1% hydroquinone) in a reflux stirring device under 80℃ water bath conditions. Slowly add 9.6g (0.125mol) of acrylic acid and sample and test until the epoxy group is 1120cm -1 The infrared peak of the band disappeared. The excess acrylic acid and solvent were removed by rotary evaporation to obtain 54.2 g of white crystals.

[0087] 3. 42.2 g (0.08 mol) of the above product was dissolved in 80 g of ethanol, and 8 g (0.09 mol) of tetrafluoroboric acid was added. The mixture was stirred at 70°C in a reflux flask for 4 h, and then transferred to a rotary evaporator to remove excess solvent to obtain the final product.

[0088] 4. Prepare a 3D printing resin composition according to the following proportions: 15% (30 g) of the above product, 40% (80 g) of aliphatic acrylate, 42% (84 g) of 4-acryloylmorpholine, and 3% (6 g) of initiator, and stir at 2000 rpm in a high-speed disperser for 2 min.

[0089] Comparative Example 1

[0090] 1. Add 10.1g (0.1mol) of triethylamine to a stirring reflux flask and dissolve it in 100g of dimethyl ether, then add 16.8g (0.1mol) of 2-(2-(chloromethyl)phenyl)ethylene oxide, set the temperature to 120°C, and after 12h, pour the product into a rotary evaporation flask to remove excess reactants, then add solvent, wash twice, and continue to use rotary evaporation to remove excess solvent to obtain 22.6g of white crystalline product.

[0091] 2. 13.5 g (0.05 mol) of the above product was dissolved in 40 g of ethanol, and 4.4 g (0.05 mol) of tetrafluoroboric acid was added. The mixture was stirred at 70°C in a reflux flask for 4 h, and then transferred to a rotary evaporator to remove excess solvent to obtain the final product.

[0092] 3. Prepare a 3D printing resin composition according to the following proportions: 5% (10 g) of the above product, 50% (100 g) of aliphatic acrylate, 42% (84 g) of 4-acryloylmorpholine, and 3% (6 g) of initiator, and stir at 2000 rpm in a high-speed disperser for 2 min.

[0093] Comparative Example 2

[0094] A 3D printing resin composition was prepared according to the following proportions: 5% (10 g) of sodium fluoride, 50% (100 g) of aliphatic acrylate, 42% (84 g) of 4-acryloylmorpholine, and 3% (6 g) of initiator, and stirred at 2000 rpm for 2 min using a high-speed disperser.

[0095] Comparative Example 3

[0096] 1. Add 10.1g (0.1mol) of triethylamine to a stirring reflux flask and dissolve it in 100g of dimethyl ether, then add 16.8g (0.1mol) of 2-(2-(chloromethyl)phenyl)ethylene oxide, set the temperature to 120°C, and after 12h, pour the product into a rotary evaporation flask to remove excess reactants, then add solvent, wash twice, and continue to use rotary evaporation to remove excess solvent to obtain 22.6g of white crystalline product.

[0097] 2. Take 13.5g (0.05mol) of the above white crystals and dissolve them in 50g of acetone (containing 1% hydroquinone) in a reflux stirring device under 80℃ water bath conditions. Slowly add 3.6g (0.05mol) of acrylic acid dropwise. Sampling and testing are carried out until the epoxy group reaches 1120cm -1 The infrared peak of the band disappeared. The excess acrylic acid and solvent were removed by rotary evaporation to obtain 15.3 g of white crystals.

[0098] 3. 13.1 g (0.04 mol) of the above product was dissolved in 40 g of ethanol, and 3.5 g (0.04 mol) of tetrafluoroboric acid was added. The mixture was stirred at 150°C in a reflux flask for 24 h, and then transferred to a rotary evaporator to remove excess solvent to obtain the final product.

[0099] 4. Prepare a 3D printing resin composition according to the following proportions: 5% (10 g) of the above product, 50% (100 g) of aliphatic acrylate, 42% (84 g) of 4-acryloylmorpholine, and 3% (6 g) of initiator, and stir at 2000 rpm in a high-speed disperser for 2 minutes.

[0100] Experimental example

[0101] The photosensitive resin compositions obtained in the above Examples 1-5 and Comparative Examples 1-3 were poured into the resin tank of the 3D printing equipment and printed. The printing parameters were 300mw and the single layer curing time was 2.1s. A mechanical strip of 100mm*12mm*2mm (universal mechanical testing machine) and a disc of 10mm diameter and 1mm thickness were printed to test the fluorine release. A disc of 50mm diameter and 10mm thickness was printed to test the surface roughness. The printing strength (Mpa), the maximum fluorine release (ng·mm -2 ·d -1 ), 30-day cumulative fluoride release (ng·mm -2 ) and surface roughness (Ra).

[0102] Fluoride release test method:

[0103] Each sample was immersed in 5g of deionized water. The fluoride ion content of the leachate was measured using a fluoride ion-selective electrode. Measurements were taken daily from 1 to 30 days of immersion. The maximum fluoride release within 30 days was calculated, as was the cumulative fluoride release. The fluoride release test was conducted in accordance with GB 7484-87, "Water Quality—Determination of Fluoride—Ion-Selective Electrode Method," using a Shanghai Leici PXSJ-216F ion meter.

[0104] Surface roughness test:

[0105] The surface of the test disc was polished to Ra = 0.1, and then soaked in 100 g of deionized water. After 30 days, the sample was taken out, the test surface was wiped dry, and the roughness was tested using a surface roughness meter.

[0106] The test results are shown in Table 1.

[0107] Table 1:

[0108] test Print intensity Maximum fluoride release Cumulative fluoride release in 30 days surface roughness unit Mpa <![CDATA[ng·mm -2 ·d -1 ]]> <![CDATA[ng·mm -2 ]]> Ra Example 1 45.3 25.3 351.4 0.1 Example 2 44.5 21.4 320.8 0.1 Example 3 52.1 67.1 987.1 0.1 Example 4 40.1 12.4 225.1 0.1 Example 5 48.7 51.0 725.8 0.1 Comparative Example 1 30.1 45.1 509.1 3.5 Comparative Example 2 31.4 78.1 875.3 4.0 Comparative Example 3 34.1 34.4 401.1 0.1

[0109] It is not difficult to see from Table 1 that Examples 1-5 have obvious advantages in printing strength, fluoride ion release and surface smoothness by adding materials with high-strength fluoride salts having fluoride ion release ability.

[0110] Compared with Examples 1-3, the surfaces of the synthesized fluorides in Comparative Examples 1 and 2 became rougher after 30 days of soaking in water than those without reactive groups, indicating that high-strength fluoride salts can not only release fluorine but also ensure surface smoothness.

[0111] Compared with Example 1, the synthesized fluoride in Comparative Example 3 does not contain a tetrabenzyl group, and its strength in the 3D printing composition is significantly reduced. This indicates that the synthesized high-strength fluoride salt has enhanced the strength of the material due to its tetrabenzyl structure.

[0112] Examples 3, 4, and 5 show that the synthesized high-strength fluoride salt has good fluorine release capacity and has good fluorine release capacity at different addition amounts, and can be added in proportion according to actual fluorine release requirements.

[0113] Finally, a few points should be explained. Although the present invention has been described in detail above using general descriptions and specific embodiments, on the basis of the present invention, the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solution to deviate from the scope of the technical solution of the embodiments of the present invention.

Claims

1. A high-strength fluoride salt having the ability to release fluoride ions, characterized in that: It has the structural formula shown in Formula I: ； Where R is C n H 2n , 1≤n≤3.

2. The method for preparing the high-strength fluoride salt according to claim 1, characterized in that the steps include: S1. reacting tribenzylamine with a halide to obtain intermediate 1; S2. Intermediate 1 reacts with acrylic acid monomer in the presence of a polymerization inhibitor to obtain intermediate 2; S3. The intermediate 2 is reacted with tetrafluoroboric acid at reflux temperature of 50-150°C for 4-24 hours to obtain a high-strength fluoride salt having the ability to release fluoride ions; The halide is selected from 2-(4-(chloromethyl)phenyl)oxirane or 2-(4-(bromomethyl)phenyl)oxirane.

3. The preparation method according to claim 2, characterized in that The molar ratio of the tribenzylamine to the halide is 1:(1-3).

4. The preparation method according to claim 2, characterized in that The solvent used in steps S1 to S3 is selected from one or more of hot ethanol, ether, chloroform, benzene, toluene, xylene, ether, dichloromethane, chloroform, acetate, 1,2-dichloroethane, 1,4-dioxane, tetrahydrofuran, acetone, butanone, cyclohexanone or N,N-dimethylformamide.

5. The preparation method according to claim 2, characterized in that In step S2, the polymerization inhibitor is selected from one or more of hydroquinone, 2,5-di-tert-butylhydroquinone, 2-tert-butylhydroquinone, p-benzoquinone, methylhydroquinone and p-hydroxyanisole; And / or, the molar ratio of the intermediate 1 to the acrylic acid monomer is 1:(1-3).

6. The preparation method according to claim 5, characterized in that The molar ratio of the intermediate 1 to the acrylic acid monomer is 1:(1-1.25).

7. The preparation method according to claim 2, characterized in that In step S3, the molar ratio of the intermediate II to tetrafluoroboric acid is 1:(1-2.5).

8. Use of the high-strength fluoride salt according to claim 1 or the high-strength fluoride salt obtained by the preparation method according to any one of claims 2 to 7 in the preparation of 3D-printed orthodontic appliances.

9. A 3D printing resin composition, characterized in that The components include, by weight percentage: 0.1-20% of a monomer having a fluorine-releasing function, 80-99% of a photocurable monomer, and 1-3% of a photoinitiator; The monomer having the fluorine-releasing function is the high-strength fluoride salt according to claim 1 or the high-strength fluoride salt obtained by the preparation method according to any one of claims 2 to 7. 10.3D printed orthodontic appliance, characterized in that: The 3D printing resin composition according to claim 9 is 3D printed and cured.

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