阅读说明：本技术 一种隐形矫治器及其制备方法 (Invisible appliance and preparation method thereof ) 是由 张超 王健蓉 何龙文 代丹妮 陈堉铭 邵龙泉 于 2020-12-11 设计创作，主要内容包括：本发明提供了一种隐形矫治器及其制备方法,所述隐形矫治器是将涂层材料通过超声辅助技术引入隐形正畸基材表面得到的；该涂层材料包括氟盐、PEG、壳聚糖和纳米二氧化钛,涂层材料的制备采用PEG负载氟,获得稳定、持久的缓释氟效果,使之具备促进釉质矿化性能；PEG亦能改善纳米二氧化钛微粒在悬浮液中的分散性,提高纳米二氧化钛分散均匀性,纳米二氧化钛生物兼容性好、化学性质稳定、抑菌成效显著,其与壳聚糖结合能显著增强抑菌性,得到的隐形矫治器具有力学性能优良、长效抑菌、促进釉质矿化的特点。(The invention provides an invisible orthodontic appliance and a preparation method thereof, wherein the invisible orthodontic appliance is obtained by introducing a coating material into the surface of an invisible orthodontic base material through an ultrasonic auxiliary technology; the coating material comprises villiaumite, PEG, chitosan and nano titanium dioxide, and the PEG is adopted to load fluorine for preparing the coating material, so that a stable and lasting fluorine slow-release effect is obtained, and the coating material has the property of promoting enamel mineralization; the PEG can also improve the dispersibility of the nano titanium dioxide particles in the suspension, improve the dispersion uniformity of the nano titanium dioxide, has good biological compatibility, stable chemical property and remarkable antibacterial effect, can remarkably enhance the antibacterial property by combining with the chitosan, and the obtained invisible appliance has the characteristics of excellent mechanical property, long-acting antibacterial property and promotion of enamel mineralization.)

1. An invisible orthodontic appliance is characterized by comprising a coating material and an invisible orthodontic base material; the coating material comprises the following components: fluoride salt, PEG, chitosan and nano titanium dioxide; the particle size of the nano titanium dioxide is 10-50 nm.

2. The invisible appliance of claim 1, wherein the coating material comprises the following components in percentage by mass: 5-20% of villiaumite, 1-25% of PEG, 5-60% of chitosan and 1-50% of nano titanium dioxide.

3. The invisible appliance of claim 1, wherein the coating material comprises the following components in percentage by mass: 9.5 to 13 percent of villiaumite, 9.5 to 18 percent of PEG, 35 to 54 percent of chitosan and 27 to 37 percent of nano titanium dioxide.

4. The invisible appliance of any one of claims 1 to 3, wherein the fluoride salt is sodium fluoride, calcium fluoride, sodium monofluorophosphate or stannous fluoride.

5. The invisible appliance of claim 4, wherein the coating material is prepared by a method comprising the steps of:

s1, preparing a chitosan solution; preparing a PEG aqueous solution, adding villiaumite, and uniformly mixing to obtain a fluorine-loaded PEG aqueous solution;

s2, uniformly mixing the chitosan solution obtained in the step S1 with the fluorine-loaded PEG aqueous solution to obtain a chitosan/fluorine-loaded PEG homogeneous mixed solution;

and S3, adding the nano titanium dioxide into the homogeneous mixed liquid obtained in the step S2, and performing ultrasonic mixing to obtain the coating material.

6. The invisible appliance of claim 5, wherein the chitosan solution has a chitosan concentration of 20-30 g/L; the solvent of the chitosan solution is an acetic acid aqueous solution with the concentration of 10-500 g/L.

7. The invisible appliance of claim 5, wherein the concentration of the PEG aqueous solution is 10-250 g/L.

8. The invisible orthodontic appliance of claim 5, wherein the ultrasonic mixing in the step S3 is performed for 1-60 min, the ultrasonic power is 50-500W, and the frequency is 5-50 kHz.

9. The invisible appliance of any one of claims 5 to 8, wherein the invisible orthodontic substrate is thermoplastic polyurethane.

10. The method for preparing the invisible appliance of claim 9, comprising the following steps:

s1, pre-wetting thermoplastic polyurethane in ethanol;

s2, placing the thermoplastic polyurethane obtained in the step S1 in the coating material, and carrying out ultrasonic treatment for 1-120 min at an ultrasonic power of 50-500W and a frequency of 5-50 kHz;

and S3, cleaning the thermoplastic polyurethane obtained by the ultrasonic treatment in the step S2, drying, and carrying out vacuum die pressing to obtain the invisible appliance.

Technical Field

The invention relates to the technical field of oral medicine, in particular to an invisible orthodontic appliance and a preparation method thereof.

Background

Because of the advantages of self-taking, convenient cleaning, beautiful appearance, comfort, convenience and the like, the invisible appliance is increasingly favored by malocclusion and malformation patients in recent years. However, as the population of patients wearing invisible appliances expands, complications from the invisible appliances become more and more evident, among which enamel demineralization and caries are the most common. The invisible appliance is closely contacted with the tooth surface in the wearing process, the saliva and air flow rate of the tooth surface are reduced, the scouring capability to dental plaque of the tooth surface is weakened, and in addition, an anaerobic interface which is easy to form enables the metabolism and the microecology of bacteria to be changed, and finally enamel on the surface layer of the tooth surface is demineralized. Therefore, the urgent need of developing an invisible orthodontic appliance which can inhibit bacteria for a long time and promote enamel mineralization is to solve the difficult problem of enamel demineralization of the invisible orthodontic patient.

To the above-mentioned problem, chinese utility model patent that publication number is CN211213598U provides a can prevent stealthy ware of correcting of tooth demineralization, through designing 3 rows of drainage holes in the anterior tooth district of lingual side, preceding molar district and molar district altogether to the saliva or the bubble in the ware and the residue of liquid food are corrected in making stealthy discharge at any time, improve the sanitary environment in the oral cavity when wearing and correcting the ware. The saliva and air flow rate between the invisible orthodontic appliance and the tooth surface interface are increased by the invisible orthodontic appliance only through a physical method, the propagation of streptococcus mutans, which is a main bacterium causing enamel demineralization, is not inhibited from a chemical and biological method level, and the bacteriostatic effect is not thorough.

The Chinese patent with publication number CN111484641A provides a long-acting antibacterial dental membrane, which is characterized in That Polyurethane (TPU) on the surface of a base material is subjected to tertiary ammonification and in-situ quaternization treatment, so that a quaternary ammonium salt antibacterial group is grafted to a molecular structure on the surface of the base material, and the material has a stable and durable antibacterial effect. However, the tertiary ammonification and the quaternization related to the antibacterial dental film piece need to react for 8-20 hours, the aging performance is lacked, in addition, the prevention and the treatment of enamel demineralization need to promote the remineralization of enamel besides bacteriostasis, only the antibacterial effect is considered, the promotion of enamel mineralization is not involved, and the effect of preventing enamel demineralization needs to be further researched.

Therefore, the development of the invisible orthodontic appliance which can inhibit bacteria for a long time and promote the mineralization of the enamel has considerable necessity for solving the problem of enamel demineralization of patients in invisible orthodontic appliance.

Disclosure of Invention

The invention aims to provide an invisible appliance and a preparation method thereof, aiming at solving the problem that the existing invisible appliance can not simultaneously realize bacteriostasis and enamel demineralization prevention and control on abnormal patients. The existing invisible appliance realizes the stable and lasting fluorine slow-release characteristic to promote the mineralization of enamel and has the effect of long-acting bacteriostasis.

The invention aims to provide an invisible appliance.

The invention also aims to provide a preparation method of the invisible appliance.

The above object of the present invention is achieved by the following technical solutions:

the invention provides an invisible orthodontic appliance, which consists of a coating material and an invisible orthodontic base material; the coating material comprises the following components: fluoride salt, PEG, chitosan and nano titanium dioxide; the particle size of the nano titanium dioxide is 10-50 nm.

Chitosan is obtained by deacetylation reaction of chitin, is the only natural basic polysaccharide found at present, is a long-chain type high molecular compound, has good biocompatibility, biodegradability, bacteriostasis, adsorptivity, renewability, film-forming property and the like, and is developed and applied in the fields of food, environmental protection, medicine, agriculture and functional materials.

Nanometer titanium dioxide is a novel inorganic chemical material developed in the end of the 20 th century and the 80 th century, is one of the most actively researched inorganic nanometer materials at present, has unique properties of small particle size, large specific surface area, high surface activity, good biocompatibility, good light absorption performance, strong ultraviolet absorption capacity and the like, and is applied to health care, sewage treatment and medical industry in various fields such as the field of environmental science, the field of fine ceramics, photocatalytic materials, particularly in the aspect of antibiosis due to the non-toxicity safety.

However, researches show that the nano titanium dioxide can play a photocatalytic antibacterial role under the irradiation of ultraviolet light, the pure nano titanium dioxide has low photocatalytic efficiency, and the light response range of the nano titanium dioxide can be obviously improved after the nano titanium dioxide is compounded with chitosan. The research of the invention finds that the single chitosan has poor dispersibility when being attached to the invisible orthodontic base material TPU, and can change the surface properties of the TPU base material such as smoothness, transparency and the like, so that the aesthetic property of the invisible appliance and the accuracy of orthodontic force are influenced.

The coating material of the invisible appliance can obtain a stable fluorine slow-release effect by loading fluorine with PEG, the fluorine loading effect is lasting and stable, and enamel mineralization is promoted; meanwhile, the PEG can also improve the dispersibility of the nano titanium dioxide particles in the suspension, and simultaneously, the nano titanium dioxide can be uniformly dispersed in the system by controlling the particle size of the nano titanium dioxide, so that the stability is improved; in addition, the nano titanium dioxide has good biocompatibility, stable chemical property and remarkable bacteriostatic effect, and the combination of the nano titanium dioxide and chitosan can make up the deficiency of the chitosan, so that the nano titanium dioxide has the advantages of organic matters and inorganic matters, and the lasting bacteriostatic performance is improved.

Preferably, the coating material comprises the following components in percentage by mass: 5-20% of villiaumite, 1-25% of PEG, 5-60% of chitosan and 1-50% of nano titanium dioxide.

More preferably, the coating material comprises the following components in percentage by mass: 9.5 to 13 percent of villiaumite, 9.5 to 18 percent of PEG, 35 to 54 percent of chitosan and 27 to 37 percent of nano titanium dioxide.

Preferably, the fluoride salt is sodium fluoride, calcium fluoride, sodium monofluorophosphate or stannous fluoride.

Preferably, the preparation method of the coating material comprises the following steps:

s1, preparing a chitosan solution; preparing a PEG aqueous solution, adding villiaumite, and uniformly mixing to obtain a fluorine-loaded PEG aqueous solution;

s2, uniformly mixing the chitosan solution obtained in the step S1 with the fluorine-loaded PEG aqueous solution to obtain a chitosan/fluorine-loaded PEG homogeneous mixed solution;

and S3, adding the nano titanium dioxide into the homogeneous mixed liquid obtained in the step S2, and performing ultrasonic mixing to obtain the coating material.

The existing methods for preparing the nano titanium dioxide/chitosan composite material mainly comprise a sol-gel method, a blending crosslinking method, a hydrothermal method and a dipping coating method, but the methods cannot meet the clinical requirements due to the defects of high equipment requirement, complex process or uneven properties of the obtained material, and the like, and the nano titanium dioxide/chitosan composite material only has antibacterial property and cannot realize F-shaped nano titanium dioxide/chitosan composite material^-The sustained-release performance of the composition can not achieve the practical curative effect of preventing and treating enamel demineralization of orthodontic patients.

The coating material can obtain a stable fluorine slow-release effect by loading fluorine by PEG, and the fluorine loading effect is durable and stable; meanwhile, the PEG can also improve the dispersibility of the nano titanium dioxide particles in the suspension, so that the nano titanium dioxide is uniformly dispersed in the system, and the stability is improved; the nano titanium dioxide has good biocompatibility, stable chemical property and remarkable bacteriostatic effect, and the combination of the nano titanium dioxide and chitosan can make up the deficiency of the chitosan, so that the nano titanium dioxide has the advantages of organic matters and inorganic matters, and the lasting bacteriostatic performance is improved.

Preferably, the chitosan concentration of the chitosan solution is 20-30 g/L.

Preferably, the solvent of the chitosan solution is an acetic acid aqueous solution with the concentration of 10-500 g/L.

More preferably, the solvent of the chitosan solution is an acetic acid aqueous solution with the concentration of 20 g/L.

Preferably, the concentration of the PEG aqueous solution is 10-250 g/L.

More preferably, the concentration of the aqueous PEG solution is 30 g/L.

Preferably, the ultrasonic mixing time in the step S3 is 1-60 min, the ultrasonic power is 50-500W, and the frequency is 5-50 kHz.

More preferably, the ultrasonic blending time in step S3 is 10min, the ultrasonic power is 285W, and the frequency is 20 kHz.

Preferably, the invisible orthodontic substrate is Thermoplastic Polyurethane (TPU).

The coating material is introduced to the surface of the invisible orthodontic base material through a simple ultrasonic auxiliary technology, so that the invisible appliance has the characteristics of long acting, bacteriostasis, promotion of enamel mineralization and the like, and the sanitary environment in the oral cavity is improved when the appliance is worn.

Therefore, the invention also claims a preparation method of the invisible appliance, which comprises the following steps:

s1, pre-wetting thermoplastic polyurethane in ethanol;

s2, placing the thermoplastic polyurethane obtained in the step S1 in the coating, and carrying out ultrasonic treatment for 1-120 min at an ultrasonic power of 50-500W and a frequency of 5-50 kHz;

and S3, cleaning the thermoplastic polyurethane obtained by the ultrasonic treatment in the step S2, drying, and carrying out vacuum die pressing to obtain the invisible appliance.

Preferably, in the step S2, the ultrasonic time is 30-40 min, the ultrasonic power is 285W, and the frequency is 20 kHz.

Preferably, the cleaning in step S3 is shaking cleaning in deionized water for 5 min.

Preferably, the drying in step S3 is natural air drying.

Preferably, the vacuum molding in step S3 is molding using a dental vacuum laminator.

According to the method, chitosan, nano titanium dioxide and fluorine-loaded PEG are uniformly attached to the surface of TPU through an ultrasonic auxiliary technology to prepare chitosan/PEG/nano titanium dioxide fluorine-loaded TPU, and then the invisible appliance which has good mechanical property and thermoplasticity, long-acting bacteriostasis and enamel mineralization promotion effect is prepared through vacuum die pressing.

Compared with the prior art, the invention has the following beneficial effects:

(1) the chitosan/PEG/nano titanium dioxide fluorine-carrying composite bacteriostatic mineralizing-promoting coating material prepared by the invention uses chitosan and nano titanium dioxide as raw materials, has wide material sources and low cost, and is environment-friendly; the introduction of fluorine-carrying PEG has the advantages of simple process, lasting fluorine slow release effect, long-acting bacteriostasis and fluorine ion release.

(2) According to the invention, the chitosan/PEG/nano titanium dioxide fluorine-carrying composite antibacterial mineralization-promoting coating is introduced to the surface of the invisible orthodontic base material TPU through a simple ultrasonic auxiliary technology, so that the obtained invisible appliance has good mechanical properties and thermoplasticity, and the characteristics of long-acting bacteriostasis and promotion of enamel mineralization, the sanitary environment in the oral cavity when the appliance is worn is effectively improved, and the clinical requirements of enamel demineralization prevention and control of orthodontic patients are met.

Drawings

Fig. 1 is a flow chart of the preparation of the invisible appliance.

Detailed Description

The present invention is further illustrated by the following specific examples, which are not intended to limit the invention in any way. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

Unless otherwise indicated, reagents and materials used in the following examples are commercially available.

EXAMPLE 1 an invisible orthosis

1. Raw materials

The embodiment provides an invisible orthodontic appliance, wherein an invisible orthodontic base material is thermoplastic polyurethane, and the dosage of each component of a coating material is as follows: 0.35g of sodium fluoride, 0.5g of PEG0, 1g of chitosan and 1g of nano titanium dioxide; wherein the particle size of the nano titanium dioxide is 10 nm.

2. Preparation method

The preparation process is shown in figure 1.

(1) Preparation of the coating

S1, dissolving chitosan in 20g/L acetic acid aqueous solution, and filtering to obtain 20g/L chitosan solution; preparing 30g/L PEG aqueous solution, adding sodium fluoride, and mixing uniformly to obtain fluorine-carrying PEG aqueous solution;

s2, uniformly mixing the chitosan/acetic acid aqueous solution and the fluorine-loaded PEG aqueous solution in the step S1 to obtain a chitosan/fluorine-loaded PEG homogeneous mixed solution;

s3, adding the nano titanium dioxide into the homogeneous mixed liquid obtained in the step S2, and carrying out ultrasonic mixing for 10min at the ultrasonic power of 285W and the frequency of 20kHz to obtain the coating material.

(2) Preparation of invisible orthodontic appliance

S1, pre-wetting Thermoplastic Polyurethane (TPU) in ethanol;

s2, placing the thermoplastic polyurethane obtained in the step S1 in the coating material prepared in the step (1), wherein the ultrasonic time is 30min, the ultrasonic power is 285W, and the frequency is 20 kHz;

and S3, taking out the thermoplastic polyurethane obtained by the ultrasonic treatment in the step S2, then performing oscillation cleaning in deionized water, naturally drying, and performing vacuum die pressing to obtain the invisible appliance.

EXAMPLE 2 an invisible orthosis

1. Raw materials

The embodiment provides an invisible orthodontic appliance, wherein an invisible orthodontic base material is thermoplastic polyurethane, and the dosage of each component of a coating material is as follows: 0.35g of calcium fluoride, 0.35g of PEG, 2g of chitosan and 1g of nano titanium dioxide; wherein the particle size of the nano titanium dioxide is 10 nm.

2. Preparation method

The same as in example 1.

EXAMPLE 3 an invisible orthosis

1. Raw materials

The embodiment provides an invisible orthodontic appliance, wherein an invisible orthodontic base material is thermoplastic polyurethane, and the dosage of each component of a coating material is as follows: 0.35g of stannous fluoride, 0.35g of PEG0, 1g of chitosan and 1g of nano titanium dioxide; wherein the particle size of the nano titanium dioxide is 10 nm.

2. Preparation method

The same as in example 1.

EXAMPLE 4 an invisible orthosis

1. Raw materials

The embodiment provides an invisible orthodontic appliance, wherein an invisible orthodontic base material is thermoplastic polyurethane, and the dosage of each component of a coating material is as follows: 0.35g of sodium monofluorophosphate, 0.5g of PEG0, 1g of chitosan and 1g of nano titanium dioxide; wherein the particle size of the nano titanium dioxide is 50 nm.

2. Preparation method

The same as in example 1.

EXAMPLE 5 an invisible orthosis

1. Raw materials

The same as in example 1.

2. Preparation method

(1) Preparation of the coating

S1, dissolving chitosan in 20g/L acetic acid aqueous solution, and filtering to obtain 20g/L chitosan solution; preparing 20g/L PEG aqueous solution, adding sodium fluoride, and mixing uniformly to obtain fluorine-carrying PEG aqueous solution;

s2, uniformly mixing the chitosan/acetic acid aqueous solution and the fluorine-loaded PEG aqueous solution in the step S1 to obtain a chitosan/fluorine-loaded PEG homogeneous mixed solution;

s3, adding the nano titanium dioxide into the homogeneous mixed liquid obtained in the step S2, and carrying out ultrasonic mixing for 10min at the ultrasonic power of 285W and the frequency of 20kHz to obtain the coating material.

(2) Preparation of invisible orthodontic appliance

The same as in example 1.

EXAMPLE 6 an invisible orthosis

1. Raw materials

The same as in example 1.

2. Preparation method

(1) Preparation of the coating

S1, dissolving chitosan in 20g/L acetic acid aqueous solution, and filtering to obtain 20g/L chitosan solution; preparing 30g/L PEG aqueous solution, adding sodium fluoride, and mixing uniformly to obtain fluorine-carrying PEG aqueous solution;

s2, uniformly mixing the chitosan/acetic acid aqueous solution and the fluorine-loaded PEG aqueous solution in the step S1 to obtain a chitosan/fluorine-loaded PEG homogeneous mixed solution;

s3, adding the nano titanium dioxide into the homogeneous mixed liquid obtained in the step S2, and carrying out ultrasonic mixing for 30min at the ultrasonic power of 350W and the frequency of 20kHz to obtain the coating material.

(2) Preparation of invisible orthodontic appliance

The same as in example 1.

EXAMPLE 7 an invisible orthosis

1. Raw materials

The same as in example 1.

2. Preparation method

(1) Preparation of the coating

The same as in example 1.

(2) Preparation of invisible orthodontic appliance

S1, pre-wetting Thermoplastic Polyurethane (TPU) in ethanol;

s2, placing the thermoplastic polyurethane obtained in the step S1 in the coating material prepared in the step (1), wherein the ultrasonic time is 60min, the ultrasonic power is 285W, and the frequency is 20 kHz;

and S3, taking out the thermoplastic polyurethane obtained by the ultrasonic treatment in the step S2, then performing oscillation cleaning in deionized water, naturally drying, and performing vacuum die pressing to obtain the invisible appliance.

Comparative example 1 invisible appliance

The raw materials and the preparation method are the same as those of the invisible appliance in the example 1, and the difference is that the particle size of the nano titanium dioxide is 70 nm.

Comparative example 2 invisible appliance

1. Raw materials

The embodiment provides an invisible orthodontic appliance, wherein an invisible orthodontic base material is thermoplastic polyurethane, and the dosage of each component of a coating material is as follows: 0.35g of sodium fluoride, 0.5g of gelatin, 1g of chitosan and 1g of nano titanium dioxide; wherein the particle size of the nano titanium dioxide is 10 nm.

2. Preparation method

(1) Preparation of the coating

S1, dissolving chitosan in 20g/L acetic acid aqueous solution, and filtering to obtain 20g/L chitosan solution; dissolving gelatin in distilled water at 60 ℃ to prepare 60g/L gelatin aqueous solution, adding sodium fluoride, and mixing uniformly to obtain fluorine-carrying gelatin aqueous solution;

s2, uniformly mixing the chitosan/acetic acid aqueous solution and the fluorine-loaded gelatin aqueous solution in the step S1 to obtain a chitosan/fluorine-loaded gelatin homogeneous mixed solution;

s3, adding the nano titanium dioxide into the homogeneous mixed liquid obtained in the step S2, and carrying out ultrasonic mixing for 10min at the ultrasonic power of 285W and the frequency of 20kHz to obtain the coating material.

(2) Preparation of invisible orthodontic appliance

The same as in example 1.

Comparative example 3 invisible appliance

1. Raw materials

The embodiment provides an invisible orthodontic appliance, wherein an invisible orthodontic base material is thermoplastic polyurethane, and the dosage of each component of a coating material is as follows: 0.35g of sodium fluoride, 0.5g of PEG0.5g and 1g of chitosan.

2. Preparation method

(1) Preparation of the coating

S1, dissolving chitosan in 20g/L acetic acid aqueous solution, and filtering to obtain 20g/L chitosan solution; preparing 30g/L PEG aqueous solution, adding sodium fluoride, and mixing uniformly to obtain fluorine-carrying PEG aqueous solution;

s2, uniformly mixing the chitosan/acetic acid aqueous solution obtained in the step S1 with the fluorine-loaded PEG aqueous solution to obtain the coating material.

(2) Preparation of invisible orthodontic appliance

The same as in example 1.

Comparative example 4 invisible appliance

1. Raw materials

The embodiment provides an invisible orthodontic appliance, wherein an invisible orthodontic base material is thermoplastic polyurethane, and the dosage of each component of a coating material is as follows: 0.35g of sodium fluoride, 0.5g of PEG0, and 1g of nano titanium dioxide; wherein the particle size of the nano titanium dioxide is 10 nm.

2. Preparation method

(1) Preparation of the coating

S1, preparing 30g/L PEG aqueous solution, adding sodium fluoride, and uniformly mixing to obtain fluorine-carrying PEG aqueous solution;

s2, adding the nano titanium dioxide into the fluorine-loaded PEG aqueous solution obtained in the step S1, and carrying out ultrasonic mixing with the ultrasonic power of 285W and the frequency of 20kHz for 10min to obtain the coating material.

(2) Preparation of invisible orthodontic appliance

The same as in example 1.

Comparative example 5 invisible appliance

The raw material types and the preparation methods are the same as those of example 1, and the specific difference is that the coating material of the comparative example comprises the following components in parts by weight: 0.35g of sodium fluoride, 0.5g of PEG0.5g, 1g of chitosan and 2g of nano titanium dioxide.

Example 8 Performance testing of invisible appliances

The invisible orthodontic appliances prepared in examples 1 to 7 and comparative examples 1 to 5 were subjected to efficacy evaluation tests.

1. Experimental methods

(1) And (3) long-acting bacteriostasis test:

experiment one: the long-acting antibacterial effect is evaluated by measuring the average number of recovered colonies of streptococcus mutans, lactobacillus, actinomycetes and porphyromonas gingivalis in dental enamel lip/buccal dental plaque before wearing the invisible appliance and 24 hours after wearing the invisible appliance, and the antibacterial rate (%) (blank control group TPU average recovered colony number-modified TPU sample average recovered colony number)/blank control group TPU average recovered colony number (CFU/mL).

Experiment two: after wearing the invisible appliance for different time periods, 11, 26, 32 and 44 tooth enamel lip/buccal bacterial plaque cultures are collected, and viable count is carried out by a flat plate viable count method (10)^-8/(CFU·ml^-1))。

Experiment three: fasting with water was performed 2 hours before collection. The dental surfaces were rinsed during collection, the rolls were kept moist, the air gun dried the dental surfaces, a small spatula was used to gently scrape the plaque around the lips/buccal sides of 11, 26, 32, 44, and placed into a pre-weighed 1.5 ml Eppendorf tube for weighing. Then putting the mixture into a drying oven at 60 ℃ for 2min, completely drying the mixture, adding 50 mu l of 1M perchloric acid, sealing the mixture, extracting fluorine for 2h at room temperature, neutralizing acid with 1M sodium hydroxide, adding 1ml of deionized water, uniformly mixing the mixture by using a vortex oscillator, centrifuging the mixture at low temperature for 30min (4 ℃ and 2000g), taking 0.8ml of supernate and 0.2ml of fluorine-containing TISAB solution (0.5ppm), uniformly mixing the solution, measuring the ion concentration in the solution by using an ion selective fluorine electrode by using a standard curve method, and calculating the concentration (mu g/g, wet weight) of the plaque fluorine.

(2) Enamel mineralization efficacy test:

experiment four: the experimenter was in a fasted, water state from the first 2 hours of sample collection to the end of the day's collection. Non-irritating saliva (> 2ml) was collected from the subjects in sterile cuvettes, 2ml was aspirated and transferred to 2ml Eppendorf tubes and centrifuged at low temperature for 3min (4 ℃, 1, 2000 g). Taking 0.8ml +0.2ml fluorine-containing TISAB solution (0.5ppm), mixing well, measuring the fluorine ion concentration in the solution by using an ion selective fluorine electrode by adopting a standard curve method, and calculating the saliva fluorine concentration (ppm).

Experiment five: the coating of the invisible appliance prepared in the embodiment 1-7 of the invention is used for pretreating a glaze block at a constant temperature which is not longer than 37 at the same time, preparing a glass bottle with a cover, cleaning the glass bottle with the cover by a conventional method, sterilizing the glass bottle with the cover under high pressure, and drying the glass bottle for later use. Then adding 5ml of acid artificial demineralizing liquid into each glass bottle, respectively soaking the prepared enamel blocks into the demineralizing liquid, covering the glass bottles, placing the glass bottles in a constant temperature box, keeping the temperature at 37 ℃ for 48 hours, taking out samples, and reserving and measuring enamel Ca through the demineralizing liquid²⁺、P³⁺Elution amount.

2. Results of the experiment

TABLE 1 invisible appliance worn 24h bacteriostasis effect

As can be seen from Table 1, the invisible appliance coatings prepared in the embodiments 1 to 7 of the invention have obvious inhibition effect on the dominant bacteria of caries and chronic periodontitis, and the inhibition effect is remarkably higher than that of the comparative examples 1 to 5, which shows that the chitosan/peg/nano titanium dioxide fluorine-carrying composite coating obtained by controlling the specific coating raw materials and the specific coating dosage can realize the optimal inhibition effect on the dominant bacteria of caries and chronic periodontitis.

TABLE 2 viable count of dental plaque biofilm after wearing invisible appliance

In addition, as can be seen from table 2, the invisible appliance coatings prepared in embodiments 1 to 7 of the present invention have a long-lasting antibacterial effect on plaque microorganisms in the replacing period (about 2 weeks) of the invisible appliance, and the antibacterial effect is significantly higher than that in comparative examples 1 to 5.

TABLE 3 dental plaque fluorine concentration variation after wearing invisible appliance

TABLE 4 saliva fluorine concentration changes after wearing invisible appliance

As can be seen from tables 3 and 4, after the invisible orthodontic appliances prepared in the embodiments 1 to 7 of the invention are worn, the concentration of dental plaque and saliva fluorine ions is continuously at a higher level, and compared with the invisible orthodontic appliances prepared in the comparative examples 1 to 5, the invisible orthodontic appliances can better play the roles of bacteriostasis and mineralization promotion.

TABLE 5 enamel calcium ion elution volume (μ g/ml) after wearing invisible appliance

TABLE 6 phosphorous ion elution amount (μ g/ml) of enamel after wearing invisible appliance

From the experimental results in tables 5 and 6, it can be seen that the elution amounts of the main constituent elements (calcium ions and phosphorus ions) of enamel after the treatment of the invisible orthodontic appliances prepared in the embodiments 1 to 7 of the present invention are at a lower level, which is significantly lower than the treatment experiments of the invisible orthodontic appliances of the comparative examples 1 to 5, indicating that the enamel demineralization reaction can be more effectively inhibited.

It should be finally noted that the above examples are only intended to illustrate the technical solutions of the present invention, and not to limit the scope of the present invention, and that other variations and modifications based on the above description and thought may be made by those skilled in the art, and that all embodiments need not be exhaustive. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.