Preparation method of invisible tooth corrector of photo-thermal antibacterial PETG (Polyethylene Terephthalate Glycol) slurry

Abstract

The invention relates to a preparation method of an invisible tooth orthodontic appliance, in particular to a preparation method of an invisible tooth orthodontic appliance with photo-thermal antibacterial PETG (polyethylene terephthalate glycol) slurry, which is characterized in that thermoplastic flowability temperature conversion of PETG is taken as a guide point, and emulsion and PETG form stable chemical bonding in a limited space, so that intrinsic mechanical properties of the invisible tooth orthodontic appliance are strengthened; high-transparency, high-mechanical and high-antibacterial PETG slurry is formed through interaction reaction among hierarchical functional groups among viscous-state PETG, antibacterial emulsion and light-cured resin, and the invisible corrector is further prepared through a light-cured printing technology. Further, the three-dimensional steady-state distribution of the antibacterial material in the transparent silica sol is realized through a high-pressure dispersion process, and the interface bonding effect is enhanced. The service life of the invisible corrector is prolonged, oral health is maintained, and high-value conversion in the field of oral medical treatment is realized.

Description

Technical Field

[0001] The present invention relates to a method for preparing a dental invisible brace, and in particular to a photothermal antibacterial PETG slurry and a method for preparing a dental invisible brace. Technical Background

[0002] PETG (polyethylene terephthalate), a thermoplastic with numerous advantages, has been widely used due to its excellent physical properties, chemical stability, and environmental performance, and is gradually becoming one of the core plastic materials of the future. PETG's performance is comparable to many common plastic materials (such as polypropylene (PP) and polyethylene (PE)), and even surpasses them in certain areas. PETG's high transparency, excellent impact resistance, good formability, and strong heat resistance make it a suitable alternative to other plastics and widely used in transparent packaging, medical materials, and other fields.

[0003] Invisible braces are a significant innovation in orthodontic care in recent years, becoming an effective alternative to traditional metal braces. Typically made of transparent materials, they allow for gradual tooth position adjustment without affecting appearance, resulting in optimal treatment outcomes. PETG (polyethylene terephthalate), a transparent, tough, and biocompatible material, has become increasingly popular in the manufacture of invisible braces in recent years.

[0004] Currently, during the long-term wearing of invisible braces, especially during chewing, the surface of the PETG material may be worn, resulting in a decrease in transparency and a rough surface. In addition, the material is in contact with bacteria in the mouth for a long time, which can easily breed bacteria and cause oral health problems. Summary of the Invention

[0005] The present invention aims to provide a method for preparing invisible braces using a photothermal antibacterial PETG slurry. This method utilizes carboxylated titanium dioxide metal-coordinated with Bauhinia leaf zinc oxide to prepare an integrated antibacterial material, which undergoes a photothermal-decomposition series. Furthermore, a high-pressure dispersion process results in a three-dimensional, stable distribution of the antibacterial material in a transparent silica sol and strengthens interfacial bonding, thereby forming a novel antibacterial emulsion with low filler content, reducing the health hazards of nanofillers. A highly transparent, highly mechanically and highly antibacterial PETG slurry is formed through the interaction of hierarchical functional groups between the viscous PETG, the antibacterial emulsion, and the photocurable resin. Invisible braces are then prepared using photocurable printing technology.

[0006] The purpose of the present invention is achieved through the following technical solutions: A method for preparing a dental invisible brace appliance of a photothermal antibacterial PETG slurry, the method comprising the following preparation steps: Step 1: Place the carboxylated titanium dioxide in a container filled with anhydrous ethanol, ultrasonicate for 10 minutes, add zinc nitrate and Bauhinia leaf extract, and stir at 600 r / min for 3 hours at room temperature. After the reaction is completed, wash the reactants with anhydrous ethanol and dry them to obtain the carboxylated titanium dioxide metal-coordinated Bauhinia leaf zinc oxide antibacterial material. Step 2: The integrated antibacterial material and the silica sol were mechanically stirred at room temperature and 300 r / min for 10 minutes to form a mixed solution, and the mixed solution was dispersed by a high-pressure homogenizer to obtain a low-content antibacterial emulsion; Step 3: The PETG pellets are heated at 120°C for 30 minutes to form a viscous flow state, the container is protected from light, and the antibacterial emulsion and light-curing resin are added in sequence and stirred at a constant speed for 10 minutes to obtain a PETG slurry; Step 4: Use an LCD 3D printer to perform light-curing printing on the prepared PETG to prepare a PETG invisible brace.

[0007] The method for preparing a dental invisible brace appliance using a photothermal antibacterial PETG slurry comprises the following raw materials by mass: 100-120 parts of PETG pellets, 1-2 parts of carboxylated titanium dioxide, 4-6 parts of zinc nitrate, 5-10 parts of 2-methylimidazole, 10-20 parts of ethanol, 50-60 parts of silica sol, and 150-180 parts of light-curable resin.

[0008] The method for preparing a dental invisible brace appliance of a photothermal antibacterial PETG slurry, the specific preparation process of the carboxylated titanium dioxide in step 1 is: weighing 1.48g of succinic anhydride and 3.48mL of KH550 and dissolving them in a container containing 120mL of DMF, mixing them evenly, placing the container in an 80°C water bath and reacting at a speed of 1000r / min for 3h; secondly, placing 3g of titanium dioxide in a container containing 100mL of DMF and 9mL of deionized water, ultrasonically dispersing it for 5min, and then pouring it into the above-mentioned mixed solution and continuing to stir for 5h; after the reaction is completed, the reactant is washed with anhydrous ethanol and dried to obtain carboxylated modified titanium dioxide.

[0009] The method for preparing a photothermal antibacterial PETG slurry for invisible braces, the specific preparation process of the Bauhinia leaf extract in step 1 is: 20 g of Bauhinia leaves are washed with distilled water three times; they are finely crushed using a pestle and tar; the distilled water and the crushed plant material are continuously mixed in a 100°C water bath for 15 minutes, and then cooled at room temperature. Finally, the extract is filtered and dried to obtain the Bauhinia leaf extract.

[0010] In the method for preparing a dental invisible brace from a photothermal antibacterial PETG slurry, the working pressure of the high-pressure homogenizer in step 2 is 600 MPa and the working time is 30 minutes.

[0011] In the method for preparing a dental invisible brace appliance using a photothermal antibacterial PETG slurry, the stirring speed in step 3 is 200-400 r / min.

[0012] In the method for preparing a dental invisible brace appliance using a photothermal antibacterial PETG slurry, the light-curing resin component in step 3 is one or more of urea methyl dimethacrylate, methacrylate, and (2,4,6-trimethylbenzoyl) diphenylphosphine oxide.

[0013] In the method for preparing a dental invisible brace appliance of a photothermal antibacterial PETG slurry, the printing slice parameters in step 4 are set to a layer thickness of 100 μm, an exposure time of 3 seconds, and a closing time of 1 second between each slice.

[0014] The significant features and positive effects of the present invention are: 1. The flavonoids and polyphenols in the Bauhinia leaf extract of the present invention can enhance the synthesis of Bauhinia leaf zinc oxide nanoparticles during their formation. Their high antioxidant properties can help eliminate free radical formation, thereby prolonging the antibacterial effect of zinc ions against external bacteria. The integrated antibacterial material formed by metal coordination creates a synergistic photothermal-degradation antibacterial effect. Its stable coordination structure ensures a three-dimensional steady-state distribution in a low-filler system under high-pressure dispersion, ensuring the stability of the multi-faceted antibacterial effects of molded invisible braces.

[0015] 2. The transparent silica sol material, primarily based on silanol bonding, regulates the contact between the highly active silanol groups and titanium dioxide under high-pressure dispersion, strengthening the interfacial bonding interaction between the two. This prevents stress concentration caused by poor interface between the filler and the emulsion under external forces, which can lead to structural damage and reduced material life. The inherently high bond energy silanol network provides a strong polymer backbone for PETG braces. The multiple hydrogen bonds between PETG and the photocurable resin improve system compatibility, strengthen the coupling effect of the compatible system, and thus enhance the mechanical properties of PETG-based invisible braces.

[0016] Aiming at the core problem of the above-mentioned invisible braces having weak intrinsic mechanical properties and poor resistance to external bacterial erosion, 3. The present invention addresses the inherent problems of poor antibacterial properties and weak robustness of PETG, the raw material of current invisible braces. By introducing a low-content new antibacterial emulsion and using the thermoplastic fluidity temperature of PETG as a guide point, the two form a steady-state chemical bond in a confined space, thereby enhancing the intrinsic mechanical properties of the invisible braces. The photothermal-decomposition serialized antibacterial process is further used to hinder bacterial erosion, extend the service life of the invisible braces, maintain oral health, and achieve high-value transformation in the field of oral medicine. DETAILED DESCRIPTION

[0017] The present invention is described in detail below with reference to the embodiments.

[0018] Example 1: (no change) The present invention provides a method for preparing a dental invisible brace appliance using a photothermal antibacterial PETG slurry, which specifically comprises the following steps: Step 1: Place one part of carboxylated titanium dioxide in a container containing 10 parts of anhydrous ethanol. After ultrasonication for 10 minutes, add four parts of zinc nitrate and five parts of Bauhinia leaf extract and stir at 600 rpm for 3 hours at room temperature. After the reaction is complete, rinse with anhydrous ethanol and dry to obtain the carboxylated titanium dioxide metal-coordinated Bauhinia leaf zinc oxide antibacterial material.

[0019] Step 2: The above-mentioned integrated antibacterial material and 50 parts of silica sol were mechanically stirred and mixed at room temperature and a speed of 300 r / min for 10 minutes to form a mixed solution, and the mixed solution was dispersed by a high-pressure homogenizer to obtain a low-content antibacterial emulsion.

[0020] Step 3: 100 parts of PETG pellets were heated at 120° C. for 30 minutes to form a viscous flow state, the container was protected from light, and an antibacterial emulsion and 150 parts of a light-curing resin were added in sequence and stirred at a constant speed for 10 minutes to obtain a PETG slurry.

[0021] Step 4: Use an LCD 3D printer to perform photocuring printing on the prepared PETG to prepare a PETG invisible brace.

[0022] Example 2 (60 parts of silica sol) The present invention provides a method for preparing a dental invisible brace appliance using a photothermal antibacterial PETG slurry, which specifically comprises the following steps: Step 1: Place one part of carboxylated titanium dioxide in a container containing 10 parts of anhydrous ethanol. After ultrasonication for 10 minutes, add four parts of zinc nitrate and five parts of Bauhinia leaf extract and stir at 600 rpm for 3 hours at room temperature. After the reaction is complete, rinse with anhydrous ethanol and dry to obtain the carboxylated titanium dioxide metal-coordinated Bauhinia leaf zinc oxide antibacterial material.

[0023] Step 2: The above-mentioned integrated antibacterial material and 60 parts of silica sol were mechanically stirred and mixed at room temperature and a speed of 300 r / min for 10 minutes to form a mixed solution, and the mixed solution was dispersed by a high-pressure homogenizer to obtain a low-content antibacterial emulsion.

[0024] Step 3: 100 parts of PETG pellets were heated at 120° C. for 30 minutes to form a viscous flow state, the container was protected from light, and the antibacterial emulsion and light-curing resin were further added in sequence and stirred at a constant speed for 10 minutes to obtain a PETG slurry.

[0025] Step 4: Use an LCD 3D printer to perform photocuring printing on the prepared PETG to prepare a PETG invisible brace.

[0026] Example 3 (120 parts of PETG pellets) The present invention provides a method for preparing a dental invisible brace appliance using a photothermal antibacterial PETG slurry, which specifically comprises the following steps: Step 1: Place one part of carboxylated titanium dioxide in a container containing 10 parts of anhydrous ethanol. After ultrasonication for 10 minutes, add four parts of zinc nitrate and five parts of Bauhinia leaf extract and stir at 600 rpm for 3 hours at room temperature. After the reaction is complete, rinse with anhydrous ethanol and dry to obtain the carboxylated titanium dioxide metal-coordinated Bauhinia leaf zinc oxide antibacterial material.

[0027] Step 2: The above-mentioned integrated antibacterial material and 60 parts of silica sol were mechanically stirred and mixed at room temperature and a speed of 300 r / min for 10 minutes to form a mixed solution, and the mixed solution was dispersed by a high-pressure homogenizer to obtain a low-content antibacterial emulsion.

[0028] Step 3: 120 parts of PETG pellets were heated at 120° C. for 30 minutes to form a viscous flow state, the container was protected from light, and the antibacterial emulsion and light-curing resin were further added in sequence and stirred at a constant speed for 10 minutes to obtain a PETG slurry.

[0029] Step 4: Use an LCD 3D printer to perform photocuring printing on the prepared PETG to prepare a PETG invisible brace.

[0030] Comparative Example 1 (no carboxylated titanium dioxide) The present invention provides a method for preparing a dental invisible brace appliance using a photothermal antibacterial PETG slurry, which specifically comprises the following steps: Step 1: 4 parts zinc nitrate and 5 parts Cercis chinensis leaf extract were stirred at 600 rpm for 3 hours at room temperature. After the reaction was completed, the reactants were washed with anhydrous ethanol and dried to obtain Cercis chinensis leaf zinc oxide.

[0031] Step 2: The antibacterial material and 60 parts of silica sol were mechanically stirred at room temperature and a speed of 300 r / min for 10 minutes to form a mixed solution, and the mixed solution was dispersed by a high-pressure homogenizer to obtain a low-content antibacterial emulsion.

[0032] Step 3: 120 parts of PETG pellets were heated at 120° C. for 30 minutes to form a viscous flow state, the container was protected from light, and the antibacterial emulsion and light-curing resin were further added in sequence and stirred at a constant speed for 10 minutes to obtain a PETG slurry.

[0033] Step 4: Use an LCD 3D printer to perform photocuring printing on the prepared PETG to prepare a PETG invisible brace.

[0034] Comparative Example 2 (without antibacterial material) The present invention provides a method for preparing a dental invisible brace appliance using a photothermal antibacterial PETG slurry, which specifically comprises the following steps: Step 1: 120 parts of PETG pellets were heated at 120° C. for 30 minutes to form a viscous flow state. The container was protected from light, and silica sol and light-curing resin were further added in sequence and stirred at a constant speed for 10 minutes to obtain a PETG slurry.

[0035] Step 2: Use an LCD 3D printer to perform photocuring printing on the prepared PETG to prepare a PETG invisible brace.

[0036] Comparative Example 3 (without silica sol) The present invention provides a method for preparing a dental invisible brace appliance using a photothermal antibacterial PETG slurry, which specifically comprises the following steps: Step 1: Place one part of carboxylated titanium dioxide in a container containing 10 parts of anhydrous ethanol. After ultrasonication for 10 minutes, add four parts of zinc nitrate and five parts of Bauhinia leaf extract and stir at 600 rpm for 3 hours at room temperature. After the reaction is complete, rinse with anhydrous ethanol and dry to obtain the carboxylated titanium dioxide metal-coordinated Bauhinia leaf zinc oxide antibacterial material.

[0037] Step 2: 120 parts of PETG pellets were heated at 120° C. for 30 minutes to form a viscous flow state, the container was protected from light, and the integrated antibacterial material and light-curing resin were added in sequence and stirred at a constant speed for 10 minutes to obtain a PETG slurry.

[0038] Step 3: Use an LCD 3D printer to perform photocuring printing on the prepared PETG to prepare a PETG invisible brace.

[0039] test: Bacterial degradation test: (1) Cut samples of 5 mm × 5 mm × 0.7 mm from the invisible braces. These samples were then sterilized by high-pressure wet heat sterilization. After sterilization and drying, the test samples were stored for later use; (2) Take 0.3 mL of Escherichia coli suspension and evenly spread it on the surface of the solid culture medium plate using a sterile coating rod. Seal the plate and let it stand at room temperature for 5 minutes. Place the dried test sample on the surface of the culture medium. The culture conditions were set at 37 ± 1 ° C, 20W ultraviolet radiation, relative humidity > 90%, and positive culture for 24 hours. After the incubation, check whether there is colony growth on the surface of the sample. Colony growth on the sample surface indicates poor antibacterial property; if there is no colony, the antibacterial effect is quantitatively evaluated by measuring the diameter of the inhibition zone around the sample (using a vernier caliper).

[0040] Conclusion and Analysis: Table 1 Antibacterial test results of invisible braces prepared in various embodiments and comparative examples invisible braces Test whether the sample has colonies attached Average diameter of inhibition zone (mm) Example 1 No colony attachment 10.98 Example 2 No colony attachment 10.43 Example 3 No colony attachment 9.44 Comparative Example 1 Some colonies attached, 1.69 Comparative Example 2 There are a large number of colonies attached / Comparative Example 1 Some colonies attached 2.33 analyze: The antibacterial properties of the six groups of samples are shown in Table 1. Comparative Example 2, a negative control containing no antibacterial material, showed significant bacterial growth on the sample surface and no inhibition zone, confirming that the PETG matrix material itself lacks antibacterial properties under ultraviolet light. In stark contrast, Examples 1, 2, and 3, which incorporate carboxylated titanium dioxide metal-coordinated Bauhinia leaf zinc oxide antibacterial material and silica sol, all effectively inhibited the growth of E. coli under ultraviolet light, with no bacterial colonies attached to the sample surfaces and the formation of distinct inhibition zones. This demonstrates the excellent photothermal antibacterial efficacy of the complete formulation. Examples with varying silica sol or PETG ratios exhibited varying inhibition zone sizes. Further comparative analysis shows that the antibacterial effect of the comparative examples lacking key components is significantly reduced. Due to the lack of carboxylated titanium dioxide in comparative example 1, the photothermal antibacterial effect of the integrated material is greatly reduced, especially under ultraviolet irradiation, the antibacterial property is significantly reduced; and in comparative example 3, due to the lack of silica sol, the antibacterial material has poor dispersion in the slurry, resulting in uneven distribution in the PETG matrix and a significant reduction in the antibacterial effect.

Claims

1. A method for preparing a dental invisible brace appliance using a photothermal antibacterial PETG slurry, characterized in that: The method comprises the following preparation steps: Step 1: Place the carboxylated titanium dioxide in a container filled with anhydrous ethanol, ultrasonicate for 10 minutes, add zinc nitrate and Bauhinia leaf extract, and stir at 600 r / min for 3 hours at room temperature. After the reaction is completed, wash the reactants with anhydrous ethanol and dry them to obtain the carboxylated titanium dioxide metal-coordinated Bauhinia leaf zinc oxide antibacterial material. Step 2: The integrated antibacterial material and the silica sol are mechanically stirred at room temperature and 300 r / min for 10 minutes to form a mixed solution, and the mixed solution is dispersed by a high-pressure homogenizer to obtain a low-content antibacterial emulsion; Step 3: The PETG pellets are heated at 120°C for 30 minutes to form a viscous flow state, the container is protected from light, and the antibacterial emulsion and light-curing resin are added in sequence and stirred at a constant speed for 10 minutes to obtain a PETG slurry; Step 4: Use an LCD 3D printer to perform light-curing printing on the prepared PETG to prepare a PETG invisible brace.

2. The method for preparing a dental invisible brace appliance of a photothermal antibacterial PETG slurry according to claim 1, characterized in that: The raw materials of the PETG slurry are as follows: 100-120 parts by weight of PETG pellets, 1-2 parts by weight of carboxylated titanium dioxide, 4-6 parts by weight of zinc nitrate, 5-10 parts by weight of 2-methylimidazole, 10-20 parts by weight of ethanol, 50-60 parts by weight of silica sol, and 150-180 parts by weight of light-curing resin.

3. The method for preparing a dental invisible brace appliance of a photothermal antibacterial PETG slurry according to claim 1, characterized in that: The specific preparation process of the carboxylated titanium dioxide in step 1 is as follows: 1.48 g of succinic anhydride and 3.48 mL of KH550 are weighed and dissolved in a container containing 120 mL of DMF. After mixing evenly, the container is placed in an 80°C water bath and reacted at a speed of 1000 r / min for 3 hours; secondly, 3 g of titanium dioxide is placed in a container containing 100 mL of DMF and 9 mL of deionized water, ultrasonically dispersed for 5 minutes, and then poured into the above mixed solution and stirred for 5 hours; after the reaction is completed, the reactant is washed with anhydrous ethanol and dried to obtain carboxylated titanium dioxide.

4. The method for preparing a dental invisible brace appliance of a photothermal antibacterial PETG slurry according to claim 1, characterized in that: The specific preparation process of the Bauhinia leaf extract in step 1 is as follows: 20 g of Bauhinia leaves are washed three times with distilled water; the leaves are finely crushed using a pestle and tar; the distilled water and the crushed plant material are continuously mixed in a 100° C. water bath for 15 minutes, followed by cooling at room temperature; and finally, the extract is filtered and dried to obtain the Bauhinia leaf extract.

5. The method for preparing a dental invisible brace appliance of a photothermal antibacterial PETG slurry according to claim 1, characterized in that: In step 2, the working pressure of the high-pressure homogenizer is 600 MPa and the working time is 30 min.

6. The method for preparing a dental invisible brace appliance of a photothermal antibacterial PETG slurry according to claim 1, characterized in that: The stirring speed in step 3 is 200-400 r / min.

7. The method for preparing a dental invisible brace appliance of a photothermal antibacterial PETG slurry according to claim 1, characterized in that: The light-curing resin component in step 3 is one or more of urea methyl dimethacrylate, methacrylate, and (2,4,6-trimethylbenzoyl)diphenylphosphine oxide.

8. The method for preparing a dental invisible brace appliance of a photothermal antibacterial PETG slurry according to claim 1, characterized in that: The printing slice parameters in step 4 are set to a layer thickness of 100 μm, an exposure time of 3 s, and a closing time of 1 s between each slice.