Oxygen-producing antibacterial absorbent paper point for root canal treatment and preparation method thereof

Abstract

The present application provides an oxygen-producing antibacterial moisture-absorbing paper point for root canal treatment and a preparation method thereof, which comprises a base that can be rolled into a conical shape to adapt to the shape of a root canal and a disinfecting component applied to the surface of the base, wherein the base is made of a water-absorbing material and is suitable for being inserted into the root canal for moisture absorption; the disinfecting component can react with water in the root canal to release oxygen and / or hydrogen peroxide to kill anaerobic bacteria in the root canal. The present application integrates the functions of water absorption and antibiosis, simultaneously dries the root canal, and achieves instant disinfection of the root canal through oxygen production and hydrogen peroxide, especially having a significant killing effect on anaerobic bacteria. The device simplifies the root canal treatment steps, shortens the treatment time, improves the disinfection efficiency, and does not affect the original water absorption performance and mechanical strength, and has an excellent clinical application prospect.

Description

Technical Field

[0001] This invention belongs to the field of dental medical device technology, specifically, it relates to a moisture-absorbing paper point for root canal treatment that can release oxygen and has antibacterial function, and its preparation method. Background Technology

[0002] Pulpitis and periapical periodontitis are the most common infectious diseases in the field of oral medicine, mainly caused by bacterial infection. They can lead to severe pain, loss of tooth function, and even affect overall health. Currently, root canal treatment is the most effective and widely used standard method for treating these diseases. The core goal of root canal treatment is to thoroughly remove the source of infection within the root canal system through mechanical and chemical means, and to perform a tight root canal filling to seal the root canal system and prevent reinfection.

[0003] In the root canal treatment procedure, drying the root canal is a crucial step connecting root canal preparation and disinfection with root canal filling. Its purpose is to remove residual moisture, irrigating fluid, and potential debris from the root canal walls and interior, providing a clean and dry environment for the filling material to adhere, ensuring a tight filling. Currently, the mainstream solution for root canal treatment in the industry can be summarized in the following two steps:

[0004] 1. Mechanical drying using absorbent paper tips.

[0005] After mechanical preparation and chemical irrigation of the root canal, clinicians use a device called a "moisture-absorbing paper point" to dry the canal. A moisture-absorbing paper point is a long, tapered paper product made of high-purity cellulose with excellent absorbency. The procedure involves the dentist using forceps to pick up one or more moisture-absorbing paper points and inserting them into the root canal. Utilizing capillary action and the hydrophilicity of cellulose, the paper point absorbs any remaining moisture from the root canal. This process usually requires repeatedly replacing the paper points until the surface of the last inserted point is no longer wet, indicating that the root canal is dry. This process is essential to ensure that the root canal filling material (such as gutta-percha points and sealants) adheres tightly to the canal wall, preventing microleakage and reinfection.

[0006] 2. Chemical disinfection via intracanal medication.

[0007] Numerous studies have shown that even after thorough mechanical preparation and chemical irrigation, bacteria may still remain within the complex anatomy of the root canal system. Therefore, to maximize infection elimination, especially against persistent anaerobic bacteria, clinical practice typically involves intracanal medication after the root canal has dried. Currently, the most widely used intracanal medication is calcium hydroxide paste. Clinicians introduce the calcium hydroxide paste into the dried root canal using a spiral delivery needle or syringe, filling the entire canal cavity. Subsequently, a temporary filling material is used to seal the pulp chamber entrance. Calcium hydroxide primarily functions within the root canal as follows: its strong alkalinity (pH approximately 12.5) disrupts bacterial cell membranes and denatures proteins, thereby killing residual bacteria, particularly the anaerobic bacteria most commonly found in failed root canal treatments. However, this clinical practice has the following limitations:

[0008] The treatment cycle is long: the bactericidal effect of calcium hydroxide is not immediate. It usually needs to be sealed in the root canal for at least one week, or even longer, to achieve the desired disinfection effect. This means that patients need to go through multiple visits. The first visit is for root canal preparation and medication, and the second visit is a week or several weeks later to remove the medication and perform root canal filling, thus prolonging the entire treatment cycle.

[0009] The process is cumbersome: the sealing process itself increases the complexity and time cost of clinical operations, requiring doctors to perform additional mixing, delivery and temporary sealing operations.

[0010] Potential risks: Although the strong alkalinity of calcium hydroxide is effective in sterilization, if it extends beyond the apical foramen and enters the periapical tissue, it may cause postoperative pain, swelling, and inflammatory reactions.

[0011] Inconsistent efficacy: There is some uncertainty regarding whether calcium hydroxide can completely penetrate all areas of the root canal system, and its drug activity and clearance effect after long-term sealing.

[0012] In response to the above problems, some attempts have been made in recent years to improve the root canal disinfection or drying procedures, but none of them have been able to perfectly solve the shortcomings of the existing solutions.

[0013] Some literature reports on modifying absorbent paper tips, such as attempting to adsorb negatively charged bacteria by altering the material itself (e.g., using PVDF membranes) and giving it a positive charge. However, such research is mostly at the laboratory concept stage, and the products have not yet been commercialized. Furthermore, their antibacterial mechanism is based on physical adsorption rather than chemical killing, so the effect may be limited. In addition, there are differences in handling feel and water absorption rate compared to traditional cellulose paper tips, making widespread adoption difficult.

[0014] Some studies are dedicated to developing novel intracanal drug delivery systems, such as injectable hydrogels and fiber scaffolds, in order to achieve sustained drug release. However, these technologies are mostly in the preclinical research stage. Their preparation processes are complex and costly, and they need to be compatible with existing root canal treatment procedures (such as using syringes for delivery). In the short term, they are unlikely to replace the simple and inexpensive combination of absorbent paper points and calcium hydroxide sealing agents.

[0015] In summary, the current mainstream approach to root canal treatment, which involves "drying with absorbent paper points" and "sealing with calcium hydroxide" in separate steps, while effective, suffers from drawbacks such as long treatment cycles, cumbersome procedures, numerous patient visits, low treatment efficiency, and potential postoperative discomfort risks. Existing absorbent paper points on the market have a single function, serving merely as a physical drying tool; while other emerging root canal disinfection technologies are either still in the research stage and have not yet achieved commercial application, or their antibacterial principles are not sufficiently integrated with clinical procedures, failing to truly meet the clinical needs for efficient, simple, and integrated treatment solutions.

[0016] Therefore, developing a new type of absorbent paper tip that can achieve immediate and efficient disinfection while drying root canals, combining moisture absorption and sterilization functions, to simplify the treatment process, shorten treatment time, improve disinfection effect and patient comfort, has important clinical value and social significance. Summary of the Invention

[0017] The purpose of this invention is to overcome the shortcomings of the prior art and provide an oxygen-generating, antibacterial, and moisture-absorbing paper point for root canal treatment and its preparation method, aiming to solve the problem that traditional moisture-absorbing paper points have a single function and cannot effectively disinfect the root canal while drying it.

[0018] To achieve the above objectives, the present invention provides the following technical solution:

[0019] In a first aspect, the present invention provides an oxygen-generating, antibacterial, and moisture-absorbing paper point for root canal treatment, comprising: a base, the base being a sheet of absorbent material, the sheet itself or after being cut, being rolled into a cone shape for insertion into the root canal for moisture absorption; and a disinfectant component applied to the base, the disinfectant component being applied to the surface of the base in a spread state, wherein the disinfectant component reacts with water in the root canal to release oxygen and / or hydrogen peroxide to kill anaerobic bacteria in the root canal.

[0020] In the technical solution of this invention, the substrate is a moisture-absorbing paper tip, made of absorbent material, capable of quickly absorbing residual moisture in the root canal, achieving the basic function of root canal drying. Simultaneously, the disinfectant applied to the substrate surface is the core of this device's innovative function. This disinfectant is applied to the surface of the substrate in its spread state, ensuring uniform distribution. When this disinfectant comes into contact with residual moisture in the root canal, a chemical reaction occurs, releasing oxygen and / or hydrogen peroxide. Oxygen can inhibit or even kill anaerobic bacteria; while hydrogen peroxide, as a strong oxidant, can directly destroy the cell structure of bacteria, playing a bactericidal role. Through this mechanism, this invention achieves the integrated function of chemical disinfection while absorbing and drying moisture. Furthermore, root canal preparation may lead to apical hemorrhage; drying and hemostasis before root canal filling are crucial for tight filling. The calcium peroxide contained in this invention hydrolyzes to produce calcium ions, which may promote apical hemostasis, thereby shortening the root canal drying time and improving the effectiveness of root canal treatment.

[0021] In a preferred embodiment of the present invention, the amount of disinfectant component coated on the spreading surface of the substrate is 1-3 mg / cm². 2 By controlling the coating amount within the above range, it is possible to ensure that the coating has sufficient antibacterial effect while avoiding adverse effects on the mechanical properties or moisture absorption properties of the substrate material due to excessive coating amount.

[0022] In a preferred embodiment of the present invention, the disinfectant component comprises a solid peroxide. Solid peroxides are chemically stable, easy to store and prepare, and react with water in a mild and controllable manner, making them very suitable as a disinfectant component for root canals.

[0023] As a further preferred embodiment of the present invention, the solid peroxide is selected from at least one of calcium peroxide, sodium percarbonate, urea peroxide, and magnesium peroxide. The chemical equations for its reaction with water are as follows:

[0024] .

[0025] In this process, in addition to generating oxygen, trace amounts of hydrogen peroxide intermediates are also generated, which together play a bactericidal role.

[0026] In another preferred embodiment of the present invention, the disinfectant component comprises calcium peroxide in the form of nanoparticles. Preparing calcium peroxide into nanoparticles significantly increases its specific surface area, enhances its reaction rate and efficiency with water, thereby releasing sufficient oxygen and hydrogen peroxide in a short time, achieving rapid and efficient disinfection. Simultaneously, the nanoparticles can be more uniformly coated onto the substrate surface, forming a stable and robust coating.

[0027] According to the present invention, the substrate is a moisture-absorbing paper point. Moisture-absorbing paper points are widely used consumables in root canal treatment. Their slender, conical shape is highly compatible with the anatomical morphology of the root canal, making them easy to insert deep into the root canal for moisture absorption. Furthermore, they are made of absorbent materials such as cellulose, exhibiting excellent moisture absorption properties. Using them as a substrate allows for maximum compatibility with existing root canal treatment practices and procedures.

[0028] As a preferred embodiment of the present invention, the absorbent material is cellulose. Cellulose is a natural polymer material with excellent hydrophilicity and biocompatibility. The absorbent paper tips made from cellulose not only have good moisture absorption but are also safe and harmless to human tissues.

[0029] As a further improvement of the present invention, the oxygen-generating antibacterial absorbent paper tip is provided with an indicator or scale for measuring the working length of the root canal. By setting the indicator or scale on the base, clinicians can visually determine the position reached when inserting the absorbent paper tip, thereby accurately measuring the working length of the root canal. This design allows the device to perform root canal length measurement while absorbing moisture and disinfecting, further simplifying the root canal treatment procedure.

[0030] In a second aspect, the present invention provides a method for preparing the oxygen-generating antibacterial and moisture-absorbing paper tip described in the first aspect above, comprising the following steps:

[0031] (a) Prepare a dispersion containing disinfectant components;

[0032] (b) Apply the dispersion to the surface of a spread substrate to form a coating containing the disinfectant component;

[0033] (c) The substrate having the coating of the disinfecting component is rolled into a cone shape.

[0034] The method provided by this invention is simple in process and easy to operate, making it suitable for industrial mass production.

[0035] As a preferred embodiment of the preparation method of the present invention, the dispersion containing the disinfectant component in step (a) uses anhydrous ethanol as the dispersion medium, wherein the weight percentage concentration of the disinfectant component can be 2%-20%, preferably 5%-10%. Anhydrous ethanol, as a solvent, has good volatility and wettability to the substrate material, enabling the disinfectant component to be uniformly dispersed and effectively adhered. Controlling the concentration of the disinfectant component within the above range ensures the antibacterial effect of the coating while avoiding adverse effects on the mechanical properties or hygroscopic properties of the substrate material due to excessively high concentrations.

[0036] As a further preferred embodiment of the preparation method of the present invention, in step (b), the dispersion is applied to the substrate surface in a spread state by spraying. Spraying is a uniform and controllable coating method that can uniformly deposit the dispersion containing disinfectant components on the substrate surface in the form of tiny droplets, forming a thin and dense coating, ensuring that the disinfectant components are evenly distributed on the substrate and without damaging the internal fiber structure of the substrate.

[0037] This invention provides an oxygen-generating, antibacterial, and moisture-absorbing paper point for root canal treatment and its preparation method. The point comprises a base that can be rolled into a conical shape to adapt to the root canal morphology and a disinfecting component applied to the surface of the base. The base is made of absorbent material and is suitable for insertion into the root canal for moisture absorption. The disinfecting component reacts with water within the root canal, releasing oxygen and / or hydrogen peroxide to kill anaerobic bacteria. This invention integrates water absorption and antibacterial functions, achieving immediate disinfection of the root canal through oxygen generation and hydrogen peroxide while drying it, with a particularly significant killing effect on anaerobic bacteria. This device simplifies root canal treatment procedures, shortens treatment time, improves disinfection efficiency, and does not affect its original water absorption properties and mechanical strength, showing excellent clinical application prospects.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] Functional integration and simplified process: This invention integrates moisture absorption and disinfection functions into a single device, achieving immediate chemical disinfection while the root canal is drying. This design directly replaces the traditional step-by-step operation mode of "drying first, then sealing with medication," merging the two treatment steps into one, significantly simplifying the clinical operation process, shortening treatment time, and reducing the number of patient visits.

[0040] Highly effective and targeted sterilization: This invention utilizes the mechanism of disinfectant components reacting with water to release oxygen and hydrogen peroxide, directly altering the anaerobic microenvironment within the root canal and killing bacteria through strong oxidation. It exhibits rapid and highly effective killing of the most challenging anaerobic bacteria in root canal treatment. Experimental data shows that this device has a significant inhibitory effect on common root canal anaerobic bacteria such as *Porphyromonas gingivalis* and *Prevotella intermedius*.

[0041] Stable performance and user-friendly operation: The device of this invention uses the widely used absorbent paper tip material in clinical practice as a base. By optimizing the coating process (such as the preferred concentration of disinfectant component of 5%-10% and the spraying application method), it can achieve antibacterial properties while maintaining the excellent water absorption performance and mechanical strength of traditional absorbent paper tips. This ensures that clinicians can use it without changing their operating habits and has good clinical acceptance.

[0042] High safety and reduced complications: When using the device of this invention, the root canal is in an open state (i.e., the pulp chamber entrance is open). The oxygen released by the reaction of the disinfectant with water will not form a closed high pressure in the root canal, thereby avoiding the pressure accumulation that may be caused by traditional root canal medication in a closed environment and the resulting postoperative pain, swelling and other complications, thus improving the safety of treatment.

[0043] Promotes hemostasis and enhances clinical treatment efficacy: The calcium peroxide contained in this invention hydrolyzes to produce calcium ions, which may promote hemostasis at the root apex, thereby shortening the root canal drying time and improving the efficacy of root canal treatment. Attached Figure Description

[0044] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings, wherein:

[0045] Figure 1A This is a photograph of the substrate in a tiled state used in a specific embodiment of the present invention.

[0046] Figure 1B This is a photograph of the tip of an oxygen-generating, antibacterial, and moisture-absorbing paper provided in a specific embodiment of the present invention.

[0047] Figure 2 This is a schematic diagram illustrating the application of the oxygen-generating, antibacterial, and moisture-absorbing paper tip provided by the present invention in the operation within the root canal.

[0048] Figure 3 This is a scanning electron microscope image of the synthesized nano-calcium peroxide particles in an embodiment of the present invention.

[0049] Figure 4 Comparison of scanning electron microscope images of a control absorbent paper tip without calcium peroxide coating, an absorbent paper tip coated with 5% calcium peroxide, and an absorbent paper tip coated with 10% calcium peroxide at different magnifications.

[0050] Figure 5A and Figure 5B The images show the X-ray energy dispersive spectroscopy (EDS) results of the control absorbent paper tip without calcium peroxide coating, the absorbent paper tip coated with 5% calcium peroxide, and the absorbent paper tip coated with 10% calcium peroxide.

[0051] Figure 6 The graph shows the oxygen production capacity test results of the control absorbent paper tip without calcium peroxide coating, the absorbent paper tip coated with 5% calcium peroxide, and the absorbent paper tip coated with 10% calcium peroxide.

[0052] Figure 7 The graph shows the tensile strength test results of the control absorbent paper tip without calcium peroxide coating, the absorbent paper tip coated with 5% calcium peroxide, and the absorbent paper tip coated with 10% calcium peroxide.

[0053] Figure 8The graph shows the water absorption characteristics of the control absorbent paper tip without calcium peroxide coating, the absorbent paper tip coated with 5% calcium peroxide, and the absorbent paper tip coated with 10% calcium peroxide.

[0054] Figure 9 The graph shows the net water absorption characteristics of the control absorbent paper tip without calcium peroxide coating, the absorbent paper tip coated with 5% calcium peroxide, and the absorbent paper tip coated with 10% calcium peroxide.

[0055] Figure 10A Confocal microscopy results of *Porphyromonas gingivalis* after treatment of absorbent paper tips with different concentrations of calcium peroxide coating.

[0056] Figure 10B The optical density values ​​of Porphyromonas gingivalis after 24 hours were obtained after treating absorbent paper tips with different concentrations of calcium peroxide coating.

[0057] Figure 10C and Figure 10D The survival rate of Porphyromonas gingivalis after treatment with absorbent paper tips coated with different concentrations of calcium peroxide for 5 minutes and 10 minutes is shown in the figure.

[0058] Figure 11A Confocal microscopy results of Prevotella intermedius after the tips of absorbent paper coated with different concentrations of calcium peroxide were treated.

[0059] Figure 11B The optical density values ​​of Prevotella intermedia after 24 hours were obtained by treating the tips of absorbent paper coated with different concentrations of calcium peroxide.

[0060] Figure 11C and Figure 11D The graph shows the survival rate of Prevotella intermedius after being treated with absorbent paper tips coated with different concentrations of calcium peroxide for 5 minutes and 10 minutes.

[0061] Figure 12 This is a summary of the characteristics of the oxygen-generating, antibacterial, and moisture-absorbing paper tips of the present invention, prepared with different concentrations of calcium peroxide.

[0062] Figure 13 Images comparing the clotting effects of whole blood from miniature pigs incubated with different absorbent paper tips in inverted centrifuge tubes are shown. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0065] Example 1

[0066] This embodiment synthesizes nano-calcium peroxide as a disinfecting component in the oxygen-generating antibacterial and moisture-absorbing paper tip described in this invention.

[0067] The specific steps are as follows: At room temperature, 6 mL of 0.9 M calcium chloride (CaCl2) solution was added to 24 mL of polyethylene glycol 400 (PEG400). 200 μL of ammonia water was added while stirring. Then, while continuing to stir, 3 mL of hydrogen peroxide (H2O2) solution was slowly added dropwise at a rate of 0.2 mL / min. Subsequently, sodium hydroxide was added dropwise to adjust the pH to 11.5, allowing calcium peroxide to precipitate. After the reaction was complete, the precipitate was centrifuged and repeatedly washed with anhydrous ethanol and deionized water to remove unreacted substances and impurities. Finally, the washed precipitate was dried in a vacuum drying oven at 60 °C to obtain white powdery nano-calcium peroxide.

[0068] The synthesized nano-calcium peroxide was characterized by scanning electron microscopy (SEM), and the results are as follows: Figure 3 As shown, the particle size is uniform and at the nanoscale. The nano-calcium peroxide prepared in this embodiment, which is the "calcium peroxide existing in the form of nanoparticles" as described in subsequent embodiments, has a nanoscale particle morphology that significantly increases the specific surface area, which is beneficial for improving the reaction rate and reaction efficiency during subsequent reactions with water.

[0069] Example 2

[0070] This embodiment prepares the oxygen-generating, antibacterial, and moisture-absorbing paper tip described in this invention.

[0071] (1) Prepare the substrate in a flat state: Cut the cellulose (i.e., absorbent material) into a suitable shape so that it can be rolled into a long and thin cone shape for insertion into the root canal for moisture absorption. Spread the substrate into a flat state to facilitate subsequent coating operations.

[0072] (2) Preparation of a solution containing disinfectant: The nano calcium peroxide powder synthesized in Example 1 is used as the disinfectant and dispersed in anhydrous ethanol at a weight percentage concentration of 5% and 10%, respectively. The dispersion is fully dispersed using an ultrasonic cleaner to form a uniform and stable dispersion.

[0073] (3) Applying the solution to the spread substrate surface: Fix the spread absorbent paper tip, and use an air pressure sprayer to uniformly spray the nano-calcium peroxide anhydrous ethanol dispersion prepared in step (2) onto the spread absorbent paper tip surface to form a coating containing the disinfectant component. Control the spraying distance and air pressure during the spraying process to ensure that the coating is uniform and does not damage the fiber structure of the paper tip.

[0074] (4) Drying: After spraying, place the moisture-absorbing paper tip coated with disinfectant in a fume hood to dry naturally, allowing the anhydrous alcohol to evaporate.

[0075] (5) Roll into a cone shape: Roll the dried moisture-absorbing paper tip coated with disinfectant into a long and thin cone shape to obtain the finished oxygen-producing antibacterial moisture-absorbing paper tip.

[0076] For comparison, the tip of the absorbent paper without any coating was used as a control group.

[0077] Example 3

[0078] Characterization and performance testing of oxygen-generating antibacterial and moisture-absorbing paper tips

[0079] Material characterization and performance testing were performed on the three types of absorbent paper tips prepared in Example 2 (control group, 5% calcium peroxide coating group, and 10% calcium peroxide coating group).

[0080] 1. Application amount of disinfectant

[0081] To quantitatively analyze the load of disinfectant components on the tip of absorbent paper, the difference in weight before and after coating was used for determination.

[0082] Test method: Samples with an area of ​​1 cm² were cut from the three types of absorbent paper tips prepared in Example 2 (control group, 5% calcium peroxide coating group, and 10% calcium peroxide coating group) in a spread-out state (i.e., after drying in step (4) and before rolling back in step (5)). Five parallel samples were taken from each group. All samples were placed in a vacuum drying oven and dried at 60°C to constant weight. The weight before coating (W0) was recorded. Subsequently, the samples were coated according to the preparation method of Example 2, and dried again under the same conditions to constant weight. The weight after coating (W1) was recorded. The amount of disinfectant coating was calculated according to the following formula:

[0083] Coating amount (mg / cm²) = (W1 - W0) / sample area

[0084] The test results are as follows:

[0085]

[0086] Test results showed that the amount of disinfectant applied to the 5% calcium peroxide coating group was approximately 1.270 ± 0.237 mg / cm³. 2 The coating weight of the 10% calcium peroxide coating group was approximately 2.665 ± 0.324 mg / cm³. 2 The control group did not detect any disinfectant components, proving the effectiveness of the coating process.

[0087] 2. Analysis of disinfection component load after rolling

[0088] To investigate the impact of the rolling process on the load of disinfectant components and to verify the performance consistency of the final product, an overall load analysis was conducted on the moisture-absorbing paper tip rolled into a cone shape.

[0089] Test method: Take 5 rolls of absorbent paper tips (5 each of the 5% coating group and the 10% coating group) prepared in Example 2, and record the initial weight (M0) of each absorbent paper tip. Completely immerse the absorbent paper tips in deionized water and sonicate for 30 minutes to completely dissolve and remove the disinfectant components coated on the substrate. Dry the treated absorbent paper tips at 60°C to constant weight, and record the weight after treatment (M1). The total disinfectant load of the entire absorbent paper tip is calculated using the following formula:

[0090] Total load (mg) = M1 - M0

[0091] Results analysis: Converting the load after rollback to the coating weight per unit area in the spread state, the conversion value for the 5% coating group is approximately 1.245 ± 0.237 mg / cm². 2 The equivalent value for the 10% coating group is approximately 2.415 ± 0.321 mg / cm³. 2 The coating amount in the spread state measured in Part 1 of Example 3 is basically consistent with the coating amount in the spread state.

[0092] The results show that, after thorough drying and subsequent rolling, the loss of the disinfectant component in the 5% coating group is minimal, and the loss rate in the 10% coating group is no higher than 10%. Therefore, the rolling process has a negligible impact on the coating load, and the preparation process of this invention exhibits good stability and controllability.

[0093] 3. Morphology and elemental analysis of disinfectant components

[0094] The surface morphology of the tips of three types of absorbent paper was observed using scanning electron microscopy. The results are as follows: Figure 4 As shown, the control group had a smooth surface with clearly visible cellulose fibers; while the 5% and 10% coated groups showed uniformly distributed nanoparticles on the paper tip surface, indicating that the disinfectant component had been successfully coated onto the substrate surface, and the coating amount was positively correlated with the coating solution concentration.

[0095] Elemental analysis of the sample surface was performed using X-ray energy dispersive spectroscopy, and the results are as follows: Figure 5A , 5B As shown, only C and O elements were detected in the control group; while Ca element was detected in the coating group, and the atomic percentage of Ca in the 10% coating group was 39.067%, higher than 24.013% in the 5% coating group. This result further confirms that the disinfectant coating on the substrate surface contains calcium peroxide, and when the disinfectant contains calcium peroxide in the form of nanoparticles, it can be uniformly distributed on the substrate surface.

[0096] 4. Oxygen release capacity test

[0097] Three types of absorbent paper tips were placed in sealed containers filled with deionized water, and the changes in dissolved oxygen concentration in the water were monitored in real time using a dissolved oxygen meter. The results are as follows: Figure 6 As shown, compared with the control group, the dissolved oxygen concentration of the absorbent paper tips in the 5% and 10% coating groups increased rapidly after immersion in water, indicating that the disinfectant reacts with water in the root canal and releases oxygen. The oxygen production rate and total amount in the 10% coating group were both higher than those in the 5% coating group, showing a concentration-dependent effect.

[0098] 5. Mechanical strength test

[0099] The tensile strength of three types of absorbent paper tips was tested using a universal testing machine. The test conditions were: tensile speed 10 mm / min, sample length 30 mm, and 5 samples per group. The results are as follows: Figure 7 As shown, compared with the control group (21.67±2.46 N), there was no statistically significant difference in tensile strength between the 5% coating group (18.48±2.33 N) and the 10% coating group (16.55±5.99 N) (P>0.05), indicating that the coating process of the present invention did not significantly affect the mechanical properties of the substrate moisture-absorbing paper tip.

[0100] 6. Water absorption performance test

[0101] The water absorption properties of three types of absorbent paper tips were evaluated by measuring the weight changes after immersion in deionized water for different times (0, 5, and 10 minutes) using a gravimetric method. The results are as follows: Figure 8 , 9 As shown, all samples reached water saturation within 5 minutes. Although the absolute and net water absorption of the coating group were slightly higher than those of the control group, all three demonstrated excellent hygroscopic capacity and were able to meet the clinical needs for root canal drying.

[0102] Example 4

[0103] Antibacterial performance test of oxygen-generating antibacterial moisture-absorbing paper tips

[0104] Three representative anaerobic bacteria commonly used in root canal treatment—Porphyromonas gingivalis (Pg) and Prevotella intermedia (Pi)—were selected as test strains to evaluate the antibacterial effects of the three absorbent paper points prepared in Example 2.

[0105] 1. Preparation of bacterial suspension: After activating and culturing each test strain on a suitable culture medium, bacteria in the logarithmic growth phase were collected, and the bacterial suspension concentration was adjusted to approximately 1×10⁻⁶ using sterile PBS buffer. 8 CFU / mL.

[0106] 2. Antibacterial Test: The absorbent paper tips of the control group, the 5% coated group, and the 10% coated group were placed in centrifuge tubes containing equal volumes of bacterial suspension and incubated for 5 minutes and 10 minutes respectively. After treatment, the antibacterial effect was evaluated using the following methods:

[0107] Colony forming unit (CFU) counting: The treated bacterial suspension was serially diluted 10-fold, and an appropriate amount was spread onto a solid culture medium and incubated under anaerobic conditions. The CFU were then counted. Results are as follows: Figure 10C , 10D As shown in Figures 11C and 11D. For Pg, treatment with 5% and 10% coatings for 5 minutes reduced bacterial counts from approximately 10. 8 CFU / mL decreased to 10 6 -10 5 For CFU / mL, treatment for 10 minutes yields better results. For Pi, a 10% coating group treated for 10 minutes completely killed all bacteria (CFU=0). Optical density measurement: The treated bacterial suspension was transferred to a 96-well plate, and its optical density (OD value) was measured at an appropriate wavelength to reflect the total bacterial count. Results are as follows... Figure 10B , 11B As shown in the figure. For Pg and Pi, the OD values ​​of the 5% and 10% coating groups were significantly lower than those of the control group at both 5 minutes and 10 minutes (P<0.0001).

[0108] Confocal microscopy observation: The treated bacteria were stained using a live / dead bacteria staining kit and observed using a confocal laser scanning microscope. Live bacteria showed green fluorescence, while dead bacteria showed red fluorescence. Results are as follows: Figure 10A , 11A As shown, compared with the control group, the red fluorescence intensity of the coated group (especially the 10% coated group) was significantly increased, indicating that a large number of bacteria were killed.

[0109] The above antibacterial test results show that the oxygen-generating antibacterial moisture-absorbing paper tip provided by the present invention can effectively kill anaerobic bacteria in the root canal after its disinfecting components react with water in the root canal and release oxygen and / or hydrogen peroxide.

[0110] Example 5

[0111] Preparation of oxygen-generating antibacterial moisture-absorbing paper tips with indicators

[0112] This embodiment provides an improved oxygen-generating, antibacterial, and moisture-absorbing paper tip. Based on the preparation method of Embodiment 2, an indicator or scale for measuring the working length of the root canal is pre-set on the moisture-absorbing paper tip, which serves as the base. Specifically, a scale mark is set every 1 mm or 2 mm on the slender base surface of the moisture-absorbing paper tip by printing or embossing. In clinical use, after inserting the moisture-absorbing paper tip into the root canal, the physician can visually calculate the working length of the root canal based on the number of scale marks exposed outside the root canal orifice. Thus, the oxygen-generating, antibacterial, and moisture-absorbing paper tip, equipped with an indicator or scale for measuring the working length of the root canal, allows the device to perform root canal length measurement while simultaneously absorbing moisture and disinfecting, further simplifying the root canal treatment procedure.

[0113] Example 6

[0114] Test of the coagulation properties of whole blood by absorbent paper tips

[0115] 1. Experimental Materials

[0116] a. Fresh whole blood from miniature pigs collected in sodium citrate anticoagulant tubes can activate the coagulation process after calcium ion treatment.

[0117] b. Three types of absorbent paper tip samples:

[0118] Control group: Blank absorbent paper tip (base only) without disinfectant loading;

[0119] 5% calcium peroxide group: Moisture-absorbing paper tips loaded with 5% calcium peroxide prepared according to the method of the present invention;

[0120] 10% calcium peroxide group: Moisture-absorbing paper tips loaded with 10% calcium peroxide prepared according to the method of the present invention.

[0121] 2. Experimental Methods

[0122] Take three 1.5 mL centrifuge tubes and add 0.6 mL of fresh miniature pig whole blood to each. Place a desiccant tip (completely immersed in the blood) into each centrifuge tube corresponding to its group. Incubate the centrifuge tubes in a 37°C water bath or incubator for 5 minutes. After incubation, remove the centrifuge tubes, quickly invert them, observe and record the flow or coagulation of the blood inside, and take images.

[0123] 3. Experimental Results

[0124] like Figure 13 As shown:

[0125] Control group: After the centrifuge tube was inverted, the blood in the tube flowed downwards significantly, indicating that the blood had not coagulated and still had good fluidity.

[0126] 5% calcium peroxide group: After the centrifuge tube was inverted, some blood did not flow, and the coagulated part remained at the bottom of the centrifuge tube.

[0127] 10% calcium peroxide group: Similar to the 5% group, after inversion, some blood did not flow, and the coagulated part remained at the bottom of the centrifuge tube.

[0128] The results showed that the calcium peroxide-loaded absorbent paper points of the present invention significantly promoted whole blood coagulation within 5 minutes, and both 5% and 10% loadings exhibited excellent procoagulant effects, while the control group showed no procoagulant effect. The oxygen-generating antibacterial absorbent paper points of the present invention not only kill anaerobic bacteria in root canal treatment but also help control bleeding within the root canal by promoting local coagulation, thereby improving the convenience and efficacy of treatment procedures.

[0129] In summary, this invention provides an oxygen-generating, antibacterial, and moisture-absorbing paper point for root canal treatment and its preparation method. The oxygen-generating, antibacterial, and moisture-absorbing paper point includes an elongated base made of absorbent material, suitable for insertion into the root canal for moisture absorption; and a disinfectant coating on the surface of the base. The disinfectant reacts with water within the root canal, releasing oxygen and / or hydrogen peroxide to kill anaerobic bacteria within the root canal. This device integrates moisture absorption and disinfection functions, achieving immediate and efficient killing of anaerobic bacteria while simultaneously drying the root canal through the reaction of a disinfectant coating (such as nano-calcium peroxide) with water within the root canal to release oxygen and hydrogen peroxide.

[0130] This invention offers the significant advantage of simultaneously disinfecting the root canal during the drying process using absorbent paper points. This process takes only seconds or minutes, much faster than traditional methods that require sealing calcium peroxide within the root canal for weeks. Furthermore, when using this innovative device for root canal treatment (where there is an open passageway in the tooth), the oxygen released by the calcium peroxide does not increase the pressure within the root canal. This minimizes the possibility of pressure buildup and eliminates the risks of pain and swelling typically associated with other endodontic treatments (involving the continuous application of calcium hydroxide in a sealed environment for weeks). The technical solution of this invention effectively overcomes the drawbacks of traditional root canal treatments that involve a step-by-step process of "drying first, then sealing," such as long treatment cycles and cumbersome operations. It has the advantages of integrated functions, highly efficient sterilization, stable performance, and high safety. Moreover, its preparation method is simple, highly controllable, and has good clinical application prospects and commercial development value.

[0131] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art can make various improvements and modifications without departing from the spirit and principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An oxygen-generating, antibacterial, and moisture-absorbing paper point for root canal treatment, characterized in that, include: The substrate is a sheet of absorbent material, which may be rolled into a cone shape or cut to be inserted into the root canal for moisture absorption. as well as Disinfecting ingredients are applied to the substrate, wherein the disinfecting ingredients are applied to the surface of the substrate in a spreadable state; The disinfectant reacts with water in the root canal to release oxygen and / or hydrogen peroxide, thereby killing anaerobic bacteria in the root canal.

2. The oxygen-generating, antibacterial, and moisture-absorbing paper tip according to claim 1, wherein, The amount of disinfectant applied to the spread surface of the substrate is 1-3 mg / cm². 2 .

3. The oxygen-generating, antibacterial, and moisture-absorbing paper tip according to claim 1, wherein, The disinfectant component contains solid peroxide.

4. The oxygen-generating, antibacterial, and moisture-absorbing paper tip according to claim 3, wherein, The solid peroxide is selected from at least one of calcium peroxide, sodium percarbonate, urea peroxide, and magnesium peroxide.

5. The oxygen-generating, antibacterial, and moisture-absorbing paper tip according to claim 1, wherein, The disinfectant component contains calcium peroxide in the form of nanoparticles.

6. The oxygen-generating, antibacterial, and moisture-absorbing paper tip according to claim 1, wherein, The absorbent material is cellulose.

7. The oxygen-generating, antibacterial, and moisture-absorbing paper tip according to claim 1, wherein, The oxygen-generating antibacterial moisture-absorbing paper tip is equipped with an indicator or scale for measuring the working length of the root canal.

8. The method for preparing oxygen-generating antibacterial and moisture-absorbing paper tips according to any one of claims 1 to 7, characterized in that, Includes the following steps: (a) Prepare a dispersion containing disinfectant components; (b) Apply the dispersion to the surface of a spread substrate to form a coating containing the disinfectant component; (c) The substrate having the coating of the disinfecting component is rolled into a cone shape.

9. The solution according to claim 8, wherein, The dispersion containing disinfectant in step (a) uses anhydrous ethanol as the dispersion medium, wherein the weight percentage concentration of the disinfectant is 2%-20%, preferably 5%-10%.

10. The solution according to claim 8, wherein, In step (b), the dispersion containing disinfectant components is applied to the substrate surface in a spread state by spraying.

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