Polyurethane matrix hot-pressed film material with antibacterial activity and capable of being used for invisible orthodontic correction and preparation method of polyurethane matrix hot-pressed film material

Abstract

The invention relates to the technical field of clinical medicine and biological science, and discloses a polyurethane matrix hot-pressed film material which has antibacterial activity and can be used for invisible orthodontic correction and a preparation method of the polyurethane matrix hot-pressed film material, and the invisible tooth socket film material with antibacterial activity is prepared from TPU resin and modified mesoporous silica nanoparticles in a mass ratio of (200-100): 1. The preparation method comprises the following steps: fully mixing self-made modified mesoporous silica nanoparticles with TPU (Thermoplastic Polyurethane) granules to prepare blended granules, and tabletting. The antibacterial TPU carrier material has the beneficial effects that the component nano-particles with antibacterial activity are directly added into the TPU carrier material by adopting a physical blending method, and the material has a relatively strong antibacterial effect and has the greatest advantages that the processing is simple and convenient, and the antibacterial durability of the material can be ensured. The antibacterial material disclosed by the invention is also applied to dental diaphragms and invisible correctors.

Description

Technical Field

[0001] This invention belongs to the fields of clinical medicine and bioscience technology. Specifically, it relates to a polyurethane-based hot-press film material with antibacterial activity that can be used for invisible orthodontic correction and its preparation method. Background Technology

[0002] Malocclusion refers to various deformities caused by mismatches in the relationship between teeth, occlusion, and craniofacial structures. It not only leads to poor function and aesthetics of the maxillofacial region but also affects the patient's mental health and social life. With socioeconomic development and improved living standards, more and more patients are seeking orthodontic treatment to improve their dentofacial aesthetics. At the same time, orthodontic patients are paying more attention to comfort and aesthetics during treatment. In recent years, dental materials have been continuously improved, and computer-aided design / computer-aided manufacturing (CAD / CAM) technology has developed rapidly, giving rise to clear aligner technology. This technology, through the application of CAD / CAM and rapid prototyping technologies, allows for the design of tooth movement in a three-dimensional, visualized state. By processing and manufacturing a series of high-polymer transparent clear aligner elastic plastic aligners, the magnitude and direction of the orthodontic force can be controlled, thereby achieving realistic and visualized orthodontic treatment goals. Compared to traditional fixed orthodontic appliances, clear aligners are aesthetically pleasing, comfortable, easy to put on and take off, and require fewer follow-up appointments. In recent years, they have attracted the attention of many orthodontists and patients, leading to the widespread application of clear aligner technology in the field of orthodontic treatment.

[0003] Traditional fixed orthodontic appliances such as brackets, bands, and archwires create numerous hard-to-clean areas and irregular surfaces, easily leading to food debris retention, plaque buildup, and severely hindering oral hygiene. While clear aligners are convenient to wear and remove, facilitating oral hygiene management, they require patients to wear them for at least 22 hours daily. Furthermore, the aligners cover the entire tooth surface and part of the keratinized gingiva, impeding the teeth's self-cleaning process. Frequent removal and replacement can cause the aligner material to become rough and age, making it easier for plaque to accumulate. Additionally, the rough edges of the aligners may cause damage to the periodontal tissue and oral mucosa. Therefore, modifying the materials of clear aligners for antibacterial properties is of significant clinical importance and has been a major research focus for scholars in recent years.

[0004] Thermoplastic film materials are a class of thermoplastic polymers. Due to their excellent formability, aesthetics, and shape memory, they have been widely used in clinical dentistry. They are used not only to manufacture thermoplastic retainers, occlusal plates, temporomandibular joint plates, anti-snoring devices, and bleaching devices, but also, thanks to the continuous development of CAD / CAM technology, for the fabrication of a series of invisible aligners. Thermoplastic film materials used in orthodontics are polymers with different properties, mainly including polyethylene terephthalate (PET), polyethylene terephthalate-glycol (PETG), thermoplastic polyurethane (TPU), polycarbonate (PC), polypropylene (PP), and ethylene vinyl acetate (EVA), etc. Among them, polyurethane (TPU, Thermoplastic polyurethane) is the most commonly used thermoplastic material in clear aligners. Currently, Invisalign's Ex30, Ex40, and SmartTrack models all use TPU as the matrix material. These materials have high elasticity and are considered suitable for meeting the need for gentle yet continuous orthodontic forces during treatment. TPU possesses both the mechanical properties of vulcanized rubber and the processing properties of thermoplastic polymers. Because it lacks the chemical network structure found in ordinary rubber, it can be repeatedly melted and processed. TPU boasts numerous advantages, including high tensile strength, high tear strength, high abrasion resistance, and good biocompatibility, thus it is widely used in the research of orthodontic thermoforming materials.

[0005] Arginine is a basic amino acid and the sole substrate for the synthesis of NO in the body, possessing a variety of unique physiological and pharmacological functions. Arginine plays a crucial role in the growth, metabolism, and biofilm formation of oral pathogenic microorganisms. Its metabolism can produce ammonia-based bases through the arginine deiminase pathway, maintaining pH balance within the plaque biofilm, inhibiting acid-producing cariogenic bacteria from becoming the dominant flora, and thus regulating the oral microecology. Simultaneously, arginine can upregulate the expression of endothelial nitric oxide synthase (eNOS), promoting eNOS's participation in periodontal tissue remodeling during the periodontal disease process. In summary, arginine can effectively prevent and treat dental and periodontal diseases, making it a promising bioactive substance in the field of oral medicine.

[0006] Mesoporous silica nanoparticles (MSNs) are bioactive nanomaterials with an ordered porous structure. They are simple to synthesize, highly stable, and exhibit low cytotoxicity. They can efficiently load drugs and other active substances. Their large internal surface area and pore volume enable highly precise release of loaded drugs, preventing premature release of the loaded components. Their rigid framework structure also ensures uniform dispersion. Based on these characteristics and advantages, MSNs have been widely used in the modification research of dental materials.

[0007] Currently, domestic research on antibacterial TPU materials mainly focuses on combining antibacterial agents with the material to impart antibacterial activity. Based on the different ways the antibacterial agent is combined with the material, it is specifically divided into two modification methods: physical modification and chemical modification. Chemical modification involves chemically bonding the antibacterial agent to the TPU substrate (such as grafting or block polymerization). Antibacterial TPU materials prepared using this method have long-lasting antibacterial properties and are easy to store, but the modification process is complex. Physical modification methods are simpler and more direct; the selection and dosage of the antibacterial agent can be accurately controlled. Generally, it involves blending or surface coating to obtain antibacterial materials. The antibacterial effect is exerted through the migration of the antibacterial active components in the antibacterial agent. TPU surface modification methods are diverse and relatively stable. For example, coating the surface of TPU materials with nano-TiO2 composite coatings has a good killing effect on Staphylococcus aureus. However, this type of coating modification only coats the outer layer of the material, and with the passage of time and friction, the coating is prone to peeling and becoming mottled, gradually losing its antibacterial effect. Incorporating antibacterial components into TPU matrix through physical blending, thereby endowing the TPU material with certain antibacterial activity, has become a research hotspot in recent years. Traditional organic antibacterial agents suffer from drawbacks such as poor performance, volatility, difficulty in processing, and poor chemical stability. Therefore, mesoporous nanoparticles (MSNs), which can efficiently load active pharmaceutical ingredients, can overcome these shortcomings. MSNs can load active pharmaceutical ingredients into their mesopores, achieving high loading efficiency and preventing premature drug release. This sustained release of active pharmaceutical ingredients can maintain a long-lasting antibacterial effect.

[0008] Therefore, in general, although there are many types of antibacterial TPU hot-press film materials currently being researched, there are still problems such as unsatisfactory bonding between antibacterial active ingredients and matrix materials, cumbersome preparation processes, and difficulty in large-scale industrial production.

[0009] In view of this, the present invention is proposed. Summary of the Invention

[0010] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows:

[0011] A polyurethane-based hot-press film material with antibacterial activity for use in invisible orthodontic correction, comprising TPU resin and modified mesoporous silica nanoparticles.

[0012] The polyurethane-based hot-press film material is made from the following weight components: the mass ratio of medical polyurethane material and modified mesoporous silica nanoparticles is 200-100:1.

[0013] As a preferred embodiment of the present invention, the modified mesoporous silica nanoparticles have an average particle size of approximately 183.6 nm and a specific surface area of ​​525.2 m². 2 / g.

[0014] As a preferred embodiment of the present invention, the modified mesoporous silica nanoparticles are self-made, and the preparation method is as follows:

[0015] S1: Preparation of mesoporous silica nanoparticles: Mesoporous silica nanoparticles were prepared using the sol-gel method with hexadecyltrimethylammonium bromide as the surfactant. First, 7 mL of 2 M NaOH solution was added to 1 L of distilled water at 60℃ and mixed thoroughly. Then, 2 g of CTAB was added and the mixture was stirred at high speed in a water bath at 60℃ for 0.5 h. Subsequently, 10 mL of tetraethyl orthosilicate was slowly added dropwise, and the mixture was stirred at high speed in a water bath at 60℃ for 2 h. After the reaction was completed, the mixture was washed with anhydrous ethanol and filtered to obtain a white solid. The white solid was then transferred to a three-necked flask, and 200 mL of methanol solution containing 1.25 wt% NaCl was added. The mixture was heated to reflux at 40℃ for 2 h to remove the surfactant CTAB. After filtration and washing, the mixture was dried under vacuum to obtain mesoporous silica nanoparticles.

[0016] S2: Loading arginine onto mesoporous silica nanoparticles: Silane coupling agent was added to anhydrous ethanol and ultrasonically dispersed to obtain solution a; the mesoporous silica nanoparticles prepared in step S1 were added to anhydrous ethanol and ultrasonically dispersed evenly, then solution a was added, and after rapid stirring and reaction, centrifuged, washed and dried with ethanol, and lyophilized to obtain the product denoted as NH2-MSNs; N-acylsuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide coupling agent were dispersed evenly at a mass ratio of 1:2, then NH2-MSNs were added and ultrasonically dispersed evenly, then Boc-arginine was added, and after rapid stirring and reaction, centrifuged and washed, and the obtained product was lyophilized to obtain arginine-loaded mesoporous silica nanoparticles.

[0017] As a preferred embodiment of the present invention, the dropping rate of the tetraethyl orthosilicate is 0.25 mL / min.

[0018] As a preferred embodiment of the present invention, a method for preparing a polyurethane-based hot-press film material with antibacterial activity for use in invisible orthodontic correction is also disclosed, comprising the following steps:

[0019] Step S1: Weigh the TPU substrate and add it to an oven. Dry it at 100°C for 5 hours to obtain dried TPU resin.

[0020] Step S2: Place the dried TPU resin in a mixer, add the modified mesoporous silica nanoparticles as described in requirement 3, mix and stir at 40-50°C until uniform, and then discharge the material.

[0021] Step S3: Add the uniformly mixed granules from step S2 into a twin-screw extruder and extrude them along the barrel axis at a speed of 35-45 rpm. The extrusion is carried out at multiple temperature stages: 80-120℃ for the feed temperature, 130-150℃ for the plasticizing and melting section, and 150-180℃ for the discharge section.

[0022] Step S4: The blended granules obtained in step S3 are dried in a vacuum oven at 100°C for 5 hours. Then, the mold is preheated to 180°C and pressured at 9-12 MPa using a flat vulcanizing apparatus and held for 12 minutes. After cooling, the antibacterial hot-pressed film material is obtained.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] The method for preparing the antibacterial TPU matrix hot-press film material for invisible orthodontic correction in this invention involves directly adding arginine-loaded mesoporous silica particles to a carrier material using a blending method. This gives the material strong and long-lasting antibacterial activity. The greatest advantage of this invention is its simple processing method. Secondly, the addition of arginine-loaded mesoporous silica nanoparticles ensures the durability of the material's antibacterial efficacy. Even if the material surface is worn, new antibacterial active substances in the inner layer can be exposed. Furthermore, the mesoporous silica has a large internal surface area and pore volume, serving as an effective carrier for arginine while preventing premature release, thus playing a "slow-release" role.

[0025] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0026] In the attached diagram:

[0027] Figure 1 This is a flowchart illustrating a method for preparing a polyurethane-based hot-press film material with antibacterial activity for use in invisible orthodontic correction. Detailed Implementation

[0028] This invention provides a TPU-based thermoforming film material with antibacterial activity suitable for invisible orthodontic treatment. It is composed of the following components by weight: medical-grade polyurethane material and modified mesoporous silica nanoparticles in a mass ratio of 200–100:1. The arginine-loaded mesoporous silica nanoparticles are prepared using a sol-gel method, with an average particle size of approximately 138 nm and a specific surface area of ​​approximately 525.2 m². 2 / g.

[0029] The present invention provides a method for preparing a TPU matrix hot-press film material with antibacterial activity for invisible orthodontic correction, comprising the following steps: (1) using cetyltrimethylammonium bromide (CTAB) as a surfactant, mesoporous silica nanoparticles are prepared by sol-gel method: first, 7 mL of 2 M NaOH solution is added to 1 L of distilled water at 60℃, and after thorough mixing, 2 g of CTAB is added, and the mixture is stirred at high speed at 60℃ for 0.5 h in a water bath. Then, 10 mL of TEOS is slowly added dropwise (0.25 mL / min), and the mixture is stirred at high speed in a constant temperature water bath at 60℃ for 2 h. After the reaction is completed, the mixture is washed and filtered with anhydrous ethanol to obtain a white solid. The white solid is then transferred to a three-necked flask, and 200 mL of methanol solution containing 1.25 wt% NaCl is added. The mixture is heated and refluxed at 40℃ for 2 h to remove the surfactant CTAB. After filtration and washing, the mixture is dried under vacuum to obtain mesoporous silica nanoparticles. (2) Add the silane coupling agent APTES to anhydrous ethanol and disperse it by ultrasonication to obtain solution a; (3) Add the mesoporous silica nanoparticles prepared in step (1) to anhydrous ethanol, disperse them evenly by ultrasonication, add solution a, stir rapidly until the reaction is complete, centrifuge, wash and dry with ethanol, freeze dry to obtain the product denoted as NH2-MSNs; (4) Disperse the coupling agents N-acylsuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide evenly, add NH2-MSNs and disperse them evenly by ultrasonication, then add Boc-arginine, stir rapidly until the reaction is complete, centrifuge and wash, freeze dry the obtained product, which is Arg@MSNs; (5) Mix the dried medical TPU substrate with the prepared arginine-loaded mesoporous silica nanoparticles in proportion, mix them evenly at a temperature of 40~50℃, and then extrude the mixed TPU substrate mixture in a twin-screw extruder at 35~45℃. The material is melt-extruded at a rotational speed of rpm along the axial direction of the barrel, with a feed temperature of 80-120℃, a plasticizing and melting section temperature of 130-150℃, and a discharge section temperature of 150-180℃. The resulting blended granules are dried in a vacuum oven at 80℃ for 5 hours for later use. Finally, the mold is preheated to 180℃ using a flat vulcanizing apparatus, and the blended granules obtained in the previous step are then pressed into sheets.

[0030] Example 1

[0031] A TPU-based hot-press film material with long-lasting and stable antibacterial activity for use in bracketless invisible orthodontics includes TPU resin and modified mesoporous silica nanoparticles; wherein the ratio of TPU resin to modified mesoporous silica nanoparticles is 100:1.

[0032] Example 2

[0033] A TPU-based hot-press film material with long-lasting and stable antibacterial activity for use in bracketless invisible orthodontics includes TPU resin and modified mesoporous silica nanoparticles; wherein the ratio of TPU resin to modified mesoporous silica nanoparticles is 200:1.

[0034] Comparative Example 1

[0035] A TPU-based hot-press film material for bracketless invisible orthodontics, composed of TPU resin.

[0036] The preparation method of the TPU matrix hot-press film material is as follows:

[0037] Weigh TPU resin into an oven and dry it at 110-130℃ for 2-5 hours to obtain dried TPU resin.

[0038] The dried TPU resin is added to a twin-screw extruder and melt-extruded into granules.

[0039] Finally, the mold is preheated to 180°C and pressured at 9-12 MPa using a flat vulcanizing apparatus, held for 12 minutes, and then cooled to obtain the TPU matrix hot-pressed film material.

[0040] To more clearly illustrate the present invention, the antibacterial materials prepared in Examples 1-2 and Comparative Example 1 were compared in terms of performance, and the results are shown in Table 1.

[0041] First, bacterial culture (Streptococcus mutans and Lactobacillus) was performed using the method specified in the national standard GB / T 31402-2015.

[0042] Take antibacterial material samples prepared in Examples 1-2 and Comparative Example 1 of the present invention, each with a size of 20mm×20mm×3mm (length×width×thickness). Weigh two portions of each sample. At the same time, take eight sterile petri dishes of the same size and add an equal amount of freshly prepared artificial saliva to them.

[0043] The antibacterial material samples (a total of 6) prepared in Examples 1-2 and Comparative Example 1 of this invention were added to petri dishes containing artificial saliva, leaving 2 petri dishes without samples as blank controls. Each petri dish was numbered. Following the method of GB / T 31402-2015, 100 μL of the cultured Streptococcus mutans and Lactobacillus suspension was added to the test sample and evenly spread for 20 min. The sample was then transferred to a 10 mL PBS test tube using sterile forceps, thoroughly mixed, and appropriately diluted. Two to three dilution gradients were selected, and 1 mL of the diluted solution was inoculated into petri dishes using the agar pouring method. The dishes were incubated at 35±2℃ for 48 h, and colony counts were performed, with two replicates per group. The test samples were repeated 3 times. The inhibition rate was calculated using the following formula: X = (AB) / A × 100%; where: X represents the inhibition rate (%); A represents the average colony count of the test sample before shaking; B represents the average colony count of the test sample after shaking.

[0044] The results calculated using the above formulas are shown in Table 1.

[0045] Example 1 Example 2 Comparative Example 1 Streptococcus mutans 82.5% 88.8% 20.1% Lactobacillus 83.2% 89.5% 19.2%

[0046] As can be seen from Table 1, the antibacterial hot-press film materials prepared in Examples 1-2 of the present invention have excellent anti-caries and antibacterial effects.

[0047] However, the above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made in accordance with the scope of protection of the present invention should still fall within the scope of the claims of the present invention.

Claims

1. A polyurethane-based hot-press film material with antibacterial activity for use in invisible orthodontic correction, characterized in that, Including TPU resin and modified mesoporous silica nanoparticles; The polyurethane-based hot-press film material is made from the following weight components: the mass ratio of medical polyurethane material and modified mesoporous silica nanoparticles is 200-100:

1.

2. The antibacterial polyurethane-based hot-press film material for invisible orthodontic treatment according to claim 1, characterized in that, The modified mesoporous silica nanoparticles have an average particle size of approximately 183.6 nm and a specific surface area of ​​525.2 m². 2 / g.

3. The antibacterial polyurethane-based hot-press film material for invisible orthodontic treatment and its preparation method according to claim 2, characterized in that, The modified mesoporous silica nanoparticles were prepared in-house using the following method: S1: Preparation of mesoporous silica nanoparticles: Mesoporous silica nanoparticles were prepared using the sol-gel method with hexadecyltrimethylammonium bromide as a surfactant. First, 7 mL of 2 M NaOH solution was added to 1 L of distilled water at 60℃ and mixed thoroughly. Then, 2 g of CTAB was added and the mixture was stirred at high speed in a water bath at 60℃ for 0.5 h. Subsequently, 10 mL of tetraethyl orthosilicate was slowly added dropwise, and the mixture was stirred at high speed in a water bath at 60℃ for 2 h. After the reaction was completed, the mixture was washed with anhydrous ethanol and filtered to obtain a white solid. The white solid was then transferred to a three-necked flask, and 200 mL of methanol solution containing 1.25 wt% NaCl was added. The mixture was heated to reflux at 40℃ for 2 h to remove the surfactant. After filtration and washing, the mixture was dried under vacuum to obtain mesoporous silica nanoparticles. S2: Loading arginine onto mesoporous silica nanoparticles: Silane coupling agent was added to anhydrous ethanol and ultrasonically dispersed to obtain solution a; the mesoporous silica nanoparticles prepared in step S1 were added to anhydrous ethanol and ultrasonically dispersed evenly, then solution a was added, and after rapid stirring and reaction, centrifuged, washed and dried with ethanol, and lyophilized to obtain the product denoted as NH2-MSNs; N-acylsuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide coupling agent were dispersed evenly according to the ratio, then NH2-MSNs were added and ultrasonically dispersed evenly, then Boc-arginine was added, and after rapid stirring and reaction, centrifuged and washed, and the obtained product was lyophilized to obtain arginine-loaded mesoporous silica nanoparticles.

4. The antibacterial polyurethane-based hot-press film material for invisible orthodontic treatment according to claim 3, characterized in that, The dropping rate of the tetraethyl orthosilicate was 0.25 mL / min.

5. The antibacterial polyurethane-based hot-press film material for invisible orthodontic treatment and its preparation method according to claim 3, characterized in that, The mass ratio of the N-acylsuccinimide to the 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide coupling agent is 1:

2.

6. A method for preparing a polyurethane-based hot-pressed film material with antibacterial activity for use in invisible orthodontic treatment, applicable to the polyurethane-based hot-pressed film material with antibacterial activity for use in invisible orthodontic treatment as described in any one of claims 1-4, characterized in that, Includes the following steps: Step S1: Weigh the TPU substrate and add it to an oven. Dry it at 100°C for 5 hours to obtain dried TPU resin. Step S2: Place the dried TPU resin in a mixer, add the modified mesoporous silica nanoparticles as described in requirement 3, mix and stir at 40-50°C until uniform, and then discharge the material. Step S3: Add the uniformly mixed granules from step S2 into a twin-screw extruder and extrude them along the barrel axis at a speed of 35-45 rpm. The extrusion is carried out at multiple temperature stages: 80-120℃ for the feed temperature, 130-150℃ for the plasticizing and melting section, and 150-180℃ for the discharge section. Step S4: The blended granules obtained in step S3 are dried in a vacuum oven at 100°C for 5 hours. Then, the mold is preheated to 180°C and pressured at 9-12 MPa using a flat vulcanizing apparatus and held for 12 minutes. After cooling, the antibacterial hot-pressed film material is obtained.

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