A method for imparting long-term circulation management capability of fluoride ions to dental attachment resin

Abstract

The application discloses a method for imparting long-acting fluoride ion circulation management capability to dental accessory resin, comprising the following steps: exposing a cured accessory resin containing quaternary ammonium salt functional monomers to a first fluoride ion concentration environment to make the resin slowly release fluoride ions; after the fluoride ion concentration in the resin is reduced, exposing the resin to a second fluoride ion concentration environment to make the quaternary ammonium salt functional monomers actively capture and store fluoride ions; and then, exposing the resin to the first fluoride ion concentration environment again to realize the circulation and re-release of fluoride ions. Through the reversible physical and chemical combination of the quaternary ammonium salt functional monomers to fluoride ions, the application realizes the circulation of'slow release-capture-re-release' of fluoride ions, avoids the burst release and one-time depletion of traditional fluoride-containing resin, can maintain long-acting and stable fluoride ion management capability in an orthodontic period of 2-3 years, does not affect the bonding strength of the resin, and has a wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of oral medical device materials technology, specifically to a method for endowing dental accessory resins with long-term fluoride ion circulation management capabilities. Background Technology

[0002] Orthodontics is a medical specialty that treats malocclusion. With advancements in materials science and digital technology, invisible orthodontic technology has become increasingly widely used in clinical practice due to its aesthetic appeal, comfort, and removability. During invisible orthodontic treatment, to achieve precise control of the teeth by the aligners, attachments made of composite resin are typically bonded to the tooth surfaces. These resin attachments serve as the medium for transmitting corrective forces and are essential core components for the invisible aligners to function effectively.

[0003] However, the long-term wear of clear aligners alters the oral microenvironment, making the resin attachments on the tooth surface and their marginal residues highly susceptible to bacterial adhesion. Because these attachments are often complex in shape and long-term presence, bacteria accumulate around them and produce acid, frequently leading to enamel demineralization. Although fluoride ions are widely added to dental resins due to their excellent mineralization-promoting and demineralization-inhibiting properties, traditional fluoride resins generally suffer from explosive release, and their fluoride ion reserves are rapidly depleted over time, making it difficult to cope with the 2-3 year clear aligner treatment period, resulting in a significant decrease in their long-term demineralization prevention effect.

[0004] Therefore, developing a method that can endow dental accessory resins with long-term fluoride ion management capabilities, enabling the resin to slowly release fluoride ions in the early stages of orthodontic treatment and actively recapture fluoride ions in the oral environment and achieve cyclical release when the fluoride content of the resin decreases, has important clinical significance and application value for maintaining long-term and stable enamel protection during invisible orthodontic treatment. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing invisible orthodontic accessory resins, such as short fluoride ion release cycle, easy depletion, and inability to continuously prevent demineralization, and to provide a method for endowing dental accessory resins with long-lasting fluoride ion management capabilities.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is to provide a method for endowing dental accessory resins with long-term fluoride ion circulation management capability, comprising the following steps: S1. Expose the cured accessory resin containing quaternary ammonium salt functional monomers to an environment with a first fluoride ion concentration, so that the cured accessory resin slowly releases fluoride ions; S2. After the concentration of fluoride ions inside the cured accessory resin decreases, it is exposed to a second fluoride ion concentration environment. The quaternary ammonium salt functional monomer is used to actively capture and store fluoride ions from the second fluoride ion concentration environment. S3. Expose the cured accessory resin to the first fluoride ion concentration environment again to achieve the cyclic release of fluoride ions; The fluoride ion concentration in the second fluoride ion concentration environment is higher than that in the first fluoride ion concentration environment.

[0007] The overall concept and inventive principle of this invention are as follows: The quaternary ammonium salt functional monomers (such as DMAHDM) used in this invention contain quaternary ammonium cations in their molecular structure. This invention has demonstrated through research that DMAHDM molecules possess a clear physicochemical binding ability for fluoride ions, providing thermodynamic evidence to support its recapture of fluoride ions. Molecular dynamics simulations further show that in an aqueous environment, fluoride ions spontaneously aggregate around DMAHDM; fluoride ions uniformly distributed at 0 ns tend to be distributed around DMAHDM at 10 ns, proving the rapid fluoride ion capture effect of DMAHDM.

[0008] Based on the above mechanism, the functional components in the resin can actively capture fluoride ions from the external environment and store them in the resin matrix through ion exchange. Since ion exchange is reversible, when the peripheral fluoride ion concentration is high, fluoride ions tend to bind to the cationic groups of the quaternary ammonium salt monomer; conversely, when the peripheral fluoride ion concentration is low, the fluoride ions on the cationic groups tend to be released. Accordingly, the cured accessory resin containing quaternary ammonium salt functional monomers can release fluoride ions at a controlled and relatively slow rate in the initial stage, avoiding the explosive release common in traditional materials, ensuring a stable supply of fluoride ions in the early stages of orthodontic treatment, and initially establishing a demineralization barrier. When the fluoride content inside the resin decreases, the material exhibits environmental responsiveness. When exposed to high-fluoride environments (such as high-fluoride environments created by fluoride toothpaste, fluoride varnish, or fluoride mouthwash), the functional components in the resin can actively capture fluoride ions from the external environment and store them in the resin matrix, thus achieving the effect of fluoride ion capture and re-release.

[0009] Through the aforementioned "release-capture-re-release" cycle, this accessory resin can break through the limitation of traditional materials where fluoride ions are depleted in one go, achieving long-lasting fluoride protection for orthodontic cycles of up to 2-3 years.

[0010] Furthermore, the method provided by this invention uses cured dental accessory resin as the operating object, and regulates the release and capture behavior of fluoride ions in the material by switching its chemical environment. It belongs to the material function management method, does not involve the diagnosis or treatment of diseases, and is for non-therapeutic purposes.

[0011] Furthermore, the preparation method of the cured accessory resin containing quaternary ammonium salt functional monomers provided by the present invention includes: mixing the quaternary ammonium salt functional monomers and commercially available resins in a dark room at 20-30°C for 2-4 minutes until homogeneous to obtain a fluoride-capturing resin, and storing it in a vacuum oven protected from light at room temperature; bonding the fluoride-capturing resin to the tooth surface and shaping it into the required shape, and then curing it with a light curing lamp to obtain the cured accessory resin containing quaternary ammonium salt functional monomers.

[0012] Furthermore, the quaternary ammonium salt functional monomer is selected from at least one of dimethylaminohexadecyl methacrylate (DMAHDM), dimethylaminododecyl methacrylate (DMADDM), and methacryloyloxydodecylpyridinium bromide (MDPB).

[0013] Preferably, the quaternary ammonium salt functional monomer is dimethylaminohexadecyl methacrylate (DMAHDM), synthesized from 2-(dimethylamino)ethyl methacrylate and 1-bromohexadecane via the Menshurstkin reaction. Specifically, 2-(dimethylamino)ethyl methacrylate and 1-bromohexadecane are mixed in an ethanol solvent at a molar ratio of 1:1 and reacted at 60-80°C for 12-36 hours. After the reaction is complete, the solvent is evaporated to obtain viscous DMAHDM. Based on the research of this invention, compared with other quaternary ammonium salt functional monomers, DMAHDM not only exhibits better performance in terms of resin binding ability and fluoride ion capture ability, but also possesses good bactericidal effects, thus endowing cured accessory resins with excellent antibacterial properties.

[0014] Furthermore, the cured accessory resin comprises a commercially available filling resin selected from at least one of Beautifil II manufactured by Matsukaze Corporation of Japan, Filtek™ Z350 XT manufactured by 3M Corporation of the United States, and SonicFill 2 manufactured by Kerr Corporation of the United States.

[0015] Preferably, the commercially available filling resin is Beautifil II manufactured by Matsukaze Co., Ltd. of Japan. Comparative studies have found that Beautifil II resin contains a certain amount of fluoride ions compared to other commercially available filling resins, giving the resin itself fluoride ion release properties. This invention further improves this resin by incorporating DMAHDM, resulting in a slow fluoride ion release effect in the initial stage of use, while also acquiring the ability to actively capture and re-release environmental fluoride ions, achieving long-term "slow-release-capture-re-release" cycle management of fluoride ions. Simultaneously, DMAHDM itself has antibacterial properties, which can impart additional antibacterial properties to the cured accessory resin, synergizing with the fluoride ion management function to further enhance the enamel protection effect during invisible orthodontic treatment.

[0016] Furthermore, the amount of the quaternary ammonium functional monomer added is 1%-5% of the mass of the commercially available filling resin. Studies have found that when the added mass of the quaternary ammonium functional monomer is less than 1% of the mass of the commercially available filling resin, the amount is too small to be effective; if the added amount is greater than 5%, it will lead to a decrease in bond strength, affecting the bonding effect of the resin on the tooth surface. Preferably, the amount of the quaternary ammonium functional monomer added is 2%-4% of the mass of the commercially available filling resin, more preferably 3%.

[0017] Furthermore, the first fluoride ion concentration environment is a saliva environment or a deionized water environment.

[0018] Furthermore, the second fluoride ion concentration environment is provided by fluoride toothpaste, fluoride varnish, or fluoride mouthwash. Specifically, when the user uses a high-concentration fluoride environment (such as fluoride toothpaste, fluoride varnish, or fluoride mouthwash), the functional components in the resin can actively capture fluoride ions from the external environment and store them in the resin matrix through ion exchange. Through the above-mentioned "release-capture-re-release" cycle, this accessory resin can break through the limitation of traditional materials where fluoride ions are depleted in one go, achieving long-lasting fluoride protection for up to 2-3 years of orthodontic treatment, thereby overcoming the shortcomings of existing invisible orthodontic accessory resins, such as short fluoride release cycle, easy depletion, and inability to continuously prevent demineralization.

[0019] Furthermore, the duration of exposure to the second fluoride ion concentration environment is 1 to 30 minutes.

[0020] Furthermore, the steps of exposure to a second fluoride ion concentration environment and subsequent re-exposure to a first fluoride ion concentration environment are repeated more than twice.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a method for endowing dental accessory resins with long-term fluoride ion circulation management capabilities. By alternately exposing cured accessory resins containing quaternary ammonium functional monomers to low- and high-concentration fluoride ion environments, a "slow-release-capture-re-release" cycle of fluoride ions is achieved. In the initial low-concentration environment, the resin slowly releases fluoride ions at a controllable rate, avoiding the explosive release of traditional materials and ensuring stable fluoride protection during the initial stages of orthodontic treatment. When the fluoride content within the resin decreases, exposing it to a high-concentration fluoride ion environment (such as when using fluoride toothpaste or mouthwash) allows the quaternary ammonium functional monomers in the resin to actively capture and store fluoride ions from the environment, achieving fluoride ion replenishment. Upon returning to a low-concentration environment, the captured fluoride ions are released again, continuing the protective effect on tooth enamel. This method breaks through the limitation of traditional fluoride resins where fluoride ions are depleted in a single application, maintaining a long-term, stable fluoride ion circulation management capability over an orthodontic cycle of 2-3 years, and has broad prospects for promotion and application. Attached Figure Description

[0022] Figure 1 This is a comparison chart of the fluoride ion release curves of the cured accessory resins prepared in Example 1 and the comparative example in Application Example 1 of the present invention; Figure 2 This is a comparison chart of the fluoride ion capture-re-release effects of the cured accessory resins prepared in Example 1 and the comparative example in Application Example 1 of the present invention; Figure 3 The experimental results of the binding ability of DMAHDM to fluoride ions are presented in the mechanism study of Example 1 of this invention. Figure 4 The experimental results of the binding effect of DMAHDM with fluoride ions in the mechanism study of Example 1 of this invention; Figure 5 This is a comparison chart of the shear bond strength test results of the cured accessory resins prepared in Example 1 and the comparative example in Application Example 2 of the present invention; Figure 6 This is a comparison chart of the shear bond strength test results of the cured accessory resin prepared in Example 3 of Application Example 2 of the present invention and the comparative example. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] This invention provides a method for endowing dental accessory resins with long-term fluoride ion circulation management capability, comprising the following steps: Step 1: Expose the cured attachment resin containing quaternary ammonium functional monomers to a first fluoride ion concentration environment, causing the cured attachment resin to slowly release fluoride ions; wherein, the preparation method of the cured attachment resin containing quaternary ammonium functional monomers includes: mixing the quaternary ammonium functional monomers with commercially available resin to obtain a fluoride-capturing resin; the amount of the quaternary ammonium functional monomers added is 1%-5% of the mass of the commercially available filling resin; bonding the fluoride-capturing resin to the tooth surface and shaping it into the desired form, and then curing it with a light-curing lamp to obtain the cured attachment resin containing quaternary ammonium functional monomers. The commercially available filling resin is Beautifil II, purchased from SHOFU INC., Japan, and the quaternary ammonium monomer is dimethylaminohexadecyl methacrylate (DMAHDM, C 21 H 42 (BrNO2), synthesized in the laboratory. The first fluoride ion concentration environment is a saliva environment or a deionized water environment.

[0025] Step 2: After the fluoride ion concentration inside the cured accessory resin decreases, it is exposed to a second fluoride ion concentration environment. The quaternary ammonium salt functional monomer actively captures and stores fluoride ions from this second fluoride ion concentration environment. The fluoride ion concentration in the second fluoride ion concentration environment is higher than that in the first fluoride ion concentration environment. The second fluoride ion concentration environment is provided by fluoride toothpaste, fluoride protective varnish, or fluoride mouthwash. The duration of exposure to the second fluoride ion concentration environment is 1 to 30 minutes.

[0026] Step 3: Expose the cured accessory resin again to an environment with a first fluoride ion concentration to achieve the cyclic release of fluoride ions. Steps 2 and 3 are repeated at least twice.

[0027] The present invention will be further described below with reference to specific embodiments, but these are not intended to limit the scope of the invention.

[0028] Example 1 The difference between this embodiment and the general embodiment is that the mass of the quaternary ammonium functional monomer DMAHDM added is 3% of the mass of the commercially available filling resin.

[0029] DMAHDM and commercially available filling resin (Beautifil II, Matsukaze Co., Ltd., Japan) were mixed evenly in the above proportions and then cured by light to obtain a cured accessory resin containing DMAHDM. The remaining steps were the same as in the general example.

[0030] Example 2 The difference between this embodiment and the general embodiment is that the mass of the quaternary ammonium functional monomer DMAHDM added is 1% of the mass of the commercially available filling resin. The remaining steps are the same as in Example 1.

[0031] Example 3 The difference between this embodiment and the general embodiment is that the mass of the quaternary ammonium functional monomer DMAHDM added is 5% of the mass of the commercially available filling resin. The remaining steps are the same as in Example 1.

[0032] Comparative Example This comparative example uses a commercially available filling resin (Beautifil II, Matsukaze Co., Ltd., Japan) that does not contain quaternary ammonium functional monomers, which is directly photocured to obtain a cured accessory resin.

[0033] Application Example 1: Slow-release-capture-recycled release of fluoride ions Take the cured accessory resins prepared in Example 1 and the comparative example, and operate them according to the following steps: Step 1: Immerse the cured accessory resin in deionized water, and take water samples at different time intervals (day 1, day 3, day 7, day 14, day 21, day 28) to measure the fluoride ion concentration in the water and plot the fluoride ion release curve.

[0034] Step 2: After soaking for 28 days, the fluoride ion concentration inside the cured accessory resin has significantly decreased. Remove it and soak it in a solution with a concentration of 2 × 10⁻⁶ fluoride ions. 4 The quaternary ammonium salt functional monomer DMAHDM in the resin is actively captured and stored from the high concentration of fluoride ions by immersing it in a sodium fluoride solution at ppm for 10 minutes.

[0035] Step 3: After soaking, remove the cured resin attachment and place it back in fresh deionized water. Measure the fluoride ion concentration in the water daily for one week. Repeat steps 2 and 3 after one week, for a total of three cycles, to evaluate the resin's ability to repeatedly capture and release fluoride ions.

[0036] Figure 1 The initial fluoride ion release rates of the two groups of resins provided in Example 1 and the comparative example are shown. Figure 1 The results showed that both groups of resins could stably release fluoride ions in the initial stage, and the release amount increased steadily over time. However, unlike the comparative example, in the first two weeks, the fluoride ion release rate of the cured accessory resin containing the quaternary ammonium salt functional monomer provided in Example 1 was lower than that of the commercially available resin in the comparative example; while after entering the third week, the fluoride ion release rate of the cured accessory resin provided in Example 1 exceeded that of the commercially available resin in Comparative Example 1. This indicates that the addition of the quaternary ammonium salt monomer DMAHDM avoids the explosive release of fluoride ions from the resin in the early stage, resulting in a stable release effect.

[0037] Figure 2 The comparative results showed that after three immersions in a high-concentration fluoride ion solution, the cured accessory resin provided in Example 1 exhibited a higher fluoride ion release rate compared to the commercially available resin in the comparative example. After each cycle, the re-release rate of the fluoride-capturing resin was significantly higher than that of the commercially available resin, indicating that the addition of DMAHDM endowed the resin with the ability to actively capture and re-release environmental fluoride ions, and this ability remained stable across multiple cycles.

[0038] The above results confirm that the method of the present invention successfully achieves a "slow-release-capture-re-release" cycle of fluoride ions by alternately exposing the cured attachment resin to low-concentration and high-concentration fluoride ion environments. It should be noted that this application example uses a high-concentration sodium fluoride solution for in vitro accelerated testing to verify the material's fluoride ion capture and re-release capabilities in a short time. Based on these test results, those skilled in the art can reasonably expect that, in actual use of products such as fluoride toothpaste, fluoride mouthwash, or fluoride protective varnish, the same cyclical re-capture and re-release effect of fluoride ions can be achieved through long-term repeated exposure.

[0039] Mechanism Study: The Mechanism of Quaternary Ammonium Salt Monomer Capturing Fluoride Ions This invention analyzes the mechanism by which the quaternary ammonium salt monomer DMAHDM captures fluoride ions using isothermal titration calorimetry and molecular dynamics simulation.

[0040] Isothermal titration calorimetry test results ( Figure 3 From the perspective of energy metabolism, it was confirmed that the DMAHDM molecule has a clear physicochemical binding ability to fluoride ions, providing thermodynamic evidence to support its "recapture" of fluoride ions.

[0041] Molecular dynamics simulation results ( Figure 4 The results show that fluoride ions spontaneously aggregate around DMAHDM in an aqueous environment. Fluoride ions that are uniformly distributed at 0 ns tend to be distributed around DMAHDM at 10 ns, further illustrating the fluoride ion capture effect of DMAHDM.

[0042] The above mechanism study explains, from both thermodynamic and kinetic perspectives, the principle that the fluoride-capturing resin prepared in this invention can actively capture fluoride ions from a high-concentration fluoride ion environment and achieve cyclic release.

[0043] Application Example 2: Bond Strength of Fluorine Capture Resin This application example evaluates the enamel bonding strength of the fluoride-capturing resin prepared in Example 1 through an isolated tooth bonding experiment, and verifies whether the addition of DMAHDM affects the mechanical properties of the resin.

[0044] The evaluation and testing methods are as follows: (1) Sixty premolars extracted for orthodontic purposes were randomly divided into two groups. The experimental group used the fluoride-capturing resin of Example 1, and the control group used commercially available resin as a comparative example. Each group had 30 teeth. The resin was bonded to the buccal surface of the premolar crown using the same bonding operation. After bonding, 15 teeth from each group were immersed in deionized water and stored in a 37°C oven. After 24 hours, a shear strength test was performed using a universal force gauge (INSTRON, USA) to evaluate the immediate bond strength.

[0045] (2) Another 15 teeth were subjected to hot and cold cycle aging treatment to simulate the effect of long-term use in the oral cavity on the bonding strength. They were immersed in a 5°C cold water bath and a 55°C hot water bath for 30 seconds each time. After 10,000 cycles, a shear strength test was performed to evaluate the bonding strength after aging.

[0046] Experimental results are as follows Figure 5 As shown. In both immediate and post-aging tests, the fluoride-capturing resin of Example 1 exhibited similar shear strength to the commercially available resin of the comparative example. This indicates that the addition of DMAHDM did not affect the resin's enamel bonding properties, and the fluoride-capturing resin possesses sufficient bond strength to meet clinical requirements.

[0047] Figure 6 The results are obtained by testing the adhesive strength of the fluorine capture resin (DMAHDM addition of 5%) prepared in Example 3 using the same method. Figure 6 This indicates that although higher concentrations of DMAHDM are beneficial for improving fluoride ion capture capabilities, when the DMAHDM addition reaches 5%, both the immediate bond strength and the bond strength after aging show statistically significant differences compared to the comparative commercially available resin, with a decrease in bond strength. Therefore, considering both fluoride ion management capability and bond strength, the addition amount of DMAHDM should not exceed 5%, and preferably is 3%.

[0048] In summary, this invention provides a method for endowing dental accessory resins with long-term fluoride ion cyclic management capabilities. By alternately exposing cured accessory resins containing the quaternary ammonium salt functional monomer DMAHDM to low- and high-concentration fluoride ion environments, a "slow-release-capture-re-release" cycle of fluoride ions is achieved. The addition of DMAHDM makes the initial release more stable and controllable, while simultaneously endowing the resin with the ability to actively capture environmental fluoride ions and release them again. This cycle can be repeated throughout daily oral care, breaking the limitation of traditional materials where fluoride ions are depleted in a single application. Mechanism studies and bond strength tests have respectively confirmed DMAHDM's clear binding ability for fluoride ions and its advantage of not affecting the resin's mechanical properties, demonstrating broad application prospects.

[0049] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the content of this specification should be included within the protection scope of the present invention.

Claims

1. A method for endowing dental accessory resins with long-term fluoride ion circulation management capability, characterized in that, Includes the following steps: S1. Expose the cured accessory resin containing quaternary ammonium salt functional monomers to an environment with a first fluoride ion concentration, so that the cured accessory resin slowly releases fluoride ions; S2. After the concentration of fluoride ions inside the cured accessory resin decreases, it is exposed to a second fluoride ion concentration environment. The quaternary ammonium salt functional monomer is used to actively capture and store fluoride ions from the second fluoride ion concentration environment. S3. Expose the cured accessory resin to the first fluoride ion concentration environment again to achieve the cyclic release of fluoride ions; The fluoride ion concentration in the second fluoride ion concentration environment is higher than that in the first fluoride ion concentration environment.

2. The method according to claim 1, characterized in that, The quaternary ammonium salt functional monomer is selected from at least one of dimethylaminohexadecyl methacrylate, dimethylaminododecyl methacrylate, and methacryloyloxydodecyl pyridine bromide.

3. The method according to claim 2, characterized in that, The quaternary ammonium salt functional monomer is dimethylaminohexadecyl methacrylate, which is synthesized from 2-(dimethylamino)ethyl methacrylate and 1-bromohexadecane via the Menshurstkin reaction.

4. The method according to claim 1, characterized in that, The cured accessory resin comprises a commercially available filling resin, which is selected from Beautifil II manufactured by Matsukaze Corporation of Japan and Filtek manufactured by 3M Corporation of the United States. TM At least one of the following: Z350 XT, SonicFill 2 manufactured by Kerr Corporation of the United States.

5. The method according to claim 4, characterized in that, The commercially available filling resin is Beautifil II manufactured by Matsukaze Co., Ltd. of Japan.

6. The method according to claim 4, characterized in that, The amount of the quaternary ammonium functional monomer added is 1%-5% of the mass of commercially available filling resin.

7. The method according to claim 1, characterized in that, The first fluoride ion concentration environment is a saliva environment or a deionized water environment.

8. The method according to claim 1, characterized in that, The second fluoride ion concentration environment is provided by fluoride toothpaste, fluoride varnish, or fluoride mouthwash.

9. The method according to claim 1, characterized in that, The duration of exposure to the second fluoride ion concentration ranges from 1 to 30 minutes.

10. The method according to claim 1, characterized in that, The steps of exposure to a second fluoride ion concentration and subsequent re-exposure to a first fluoride ion concentration were repeated more than twice.

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