Composite root canal filling agent of premixed calcium silicate-niobium compound as well as preparation method and application of composite root canal filling agent

Abstract

The invention relates to the technical field of medical materials, in particular to a composite root canal filling agent premixed with a calcium silicate-niobium compound as well as a preparation method and application of the composite root canal filling agent. The composite root canal filling agent comprises (a) a calcium silicate compound, (b) a phosphate compound, (c) a calcium compound, (d) a niobium compound, (e) a radiation-resistant material, (f) a water-miscible non-aqueous phase solvent and (g) an organic matter, the total mass of the component (a), the component (b), the component (c), the component (d), the component (e) and the component (g) accounts for 60-95% of the total mass of the filling agent, and the total mass of the component (a), the component (b), the component (c), the component (d), the component (e) and the component (g) accounts for 20-30% of the total mass of the filling agent. And the component (f) accounts for 5-40% of the total mass of the filling agent. The filling agent is fast in solidification, good in biological activity, excellent in antibacterial performance and convenient to popularize and apply.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical materials, in particular to a premixed calcium silicate-niobium compound composite root canal filling agent, a preparation method and application thereof. BACKGROUND

[0002] Root canal diseases mainly cover two common conditions of pulpitis and periapical periodontitis. Pulpitis often occurs due to bacterial infection or stimulation of pulp tissue, and its typical symptoms include local pain of the tooth, sensitive reaction to hot and cold stimulation, etc. Periapical periodontitis is caused by unhealed or incompletely healed pulpitis, leading to infection spreading to the tissue around the root tip, and further causing local inflammatory reaction and bone damage. Current root canal treatment has certain effect, but still faces many challenges, such as the complex structure of the root canal system and multiple difficulties in the treatment process.

[0003] Necrotic dental pulp is a breeding ground for microorganisms, which multiply in the form of planktonic cells, aggregates or biofilms. Enterococcus faecalis is the most common isolated bacterium in the root canals of patients with persistent apical periodontitis. Enterococcus faecalis can penetrate dentin tubules up to 159-1790 μm in depth and survive root canal therapy, and its ability to adapt to changing environments and form single-species biofilms helps Enterococcus faecalis tolerate the harsh microenvironment encountered in teeth after root canal therapy, resulting in a secondary root canal infection prevalence of 24%-77%. Studies have shown that if these diseases are not effectively treated, they can lead to tooth loss or severe oral infections.

[0004] Root canal therapy includes physical therapy, chemical therapy and biological therapy. In the overall treatment process, the pain point in the physical layer is that mechanical instruments cannot completely eradicate the infection in the canal, which will lead to 2.66-79.0% of the canal surface that cannot be treated by instrument therapy. Secondly, the complex internal structure of the root canal includes a system of small channels, side branches and nonlinear profiles, which not only increase the technical difficulty of root canal therapy, but also affect the success rate and prognosis of the treatment. The complex internal structure of the root canal provides an ideal living environment for oral pathogenic bacteria such as Enterococcus faecalis, which can form biofilms in the pulp chamber and side branches. The presence of biofilms not only enhances the drug resistance and survival ability of the bacterial population, but also makes effective flushing during root canal therapy more difficult and complex. Disinfection based on flushing plays an indispensable role in purifying microorganisms and their byproducts. Among various flushing agents, sodium hypochlorite is still the first choice due to its antibacterial and dissolving pulp tissue activity. However, it has a high concentration of tissue damage risk, which can cause dentin decalcification, and also has cytotoxicity, on the contrary, in low concentration, the flushing effect is poor.

[0005] Root canal therapy is a challenging technical task in modern dentistry, mainly due to the complex structure of the root canal system and the multiple difficulties involved in the treatment process. The micro-channels, side channels and non-linear profile within the root canal system constitute the primary difficulty in treatment. Secondly, the treatment process involves not only the simple removal of apical tissue or the apex, but more importantly, ensuring the complete sealing of the root canal system to prevent the occurrence of re-infection. In this case, if our root canal filling material has effective antibacterial properties and can still play a continuous antibacterial role after root canal filling, effectively controlling the infection of microorganisms in the root canal and the biofilm outside the root foramen, it will help to increase the success rate of root canal therapy and reduce the incidence of refractory periapical periodontitis.

[0006] Bioceramic root canal filling paste contains calcium phosphate, calcium silicate, zirconium oxide and calcium hydroxide and other ingredients, and has a similar composition to white MTA. These materials are recognized for their good sealing, stability and antibacterial properties. They do not dissolve in tissue fluid, can maintain long-term stability, and release hydroxyl ions during and after setting to maintain a high pH, thereby inhibiting bacterial growth. In addition, bioceramic root canal filling paste has good biocompatibility, no toxic side effects, and can be used for root apex induction and root canal repair. However, this type of biocompatible filling paste has certain limitations in promoting immature pulp removal paste. SUMMARY

[0007] In order to solve the above problems, the purpose of the present application is to provide a pre-mixed calcium silicate-niobium compound composite root canal filling agent and a preparation method thereof. In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0008] A pre-mixed calcium silicate-niobium compound composite root canal filling agent, comprising:

[0009] (a) a calcium silicate compound, (b) a phosphate compound, (c) a calcium compound, (d) a niobium compound, (e) a barrier material, (f) a non-aqueous phase solvent miscible with water, and (g) an organic substance, wherein the total amount of components (a), (b), (c), (d), (e) and (g) is 60% to 95% of the total mass of the filling agent, and the amount of component (f) is 5% to 40% of the total mass of the filling agent.

[0010] The pre-mixed calcium silicate-niobium compound root canal filling agent is a two-phase composite self-curing system that combines the advantages of niobium oxide compounds and calcium silicate self-curing materials. Not only is the curing time significantly shortened, but it also has excellent biocompatibility, bioactivity and antibacterial properties, and can promote the further maturation of immature pulp removal root canals.

[0011] The component (a) can be selected from one or more of tricalcium silicate, dicalcium silicate and monocalcium silicate. The tricalcium silicate has a general chemical formula of Ca3SiO5, the dicalcium silicate has a general chemical formula of Ca2SiO4, and the monocalcium silicate has a general chemical formula of CaSiO3.

[0012] The calcium silicate compound is in a powder form. The powder has a particle size of 10 nm to 200 μm, and further preferably 100 μm.

[0013] Two powders of tricalcium silicate, dicalcium silicate and monocalcium silicate are preferably selected in a ratio of 1.8:1 to 2.2:1 as the main component of the material to provide good sealing and stability.

[0014] The component (b) can be selected from calcium phosphate, magnesium phosphate, sodium phosphate, zinc phosphate, iron phosphate, potassium phosphate, nickel phosphate, zirconium phosphate, phosphoric acid, organometallic phosphate and mixtures thereof. The phosphate used in the paste can contain water of hydration. More complex (pre-reacted) phosphates can also be used. Further, the calcium phosphate includes, but is not limited to, monocalcium phosphate, monocalcium phosphate, tricalcium phosphate, tetracalcium phosphate and mixtures thereof. The calcium phosphate can contain water of hydration. The source of the component (c) is not particularly limited in the present application, and commercially available products well known to those skilled in the art can be used.

[0015] The phosphate compound is in a powder form. The powder has a particle size of 10 nm to 200 μm, and further preferably 100 μm. The selection of the phosphate compound powder helps to enhance the antibacterial properties and bioactivity of the material.

[0016] The component (c) can be selected from calcium hydroxide, calcium carbonate, calcium bicarbonate and mixtures thereof. Further, the calcium phosphate includes, but is not limited to, calcium hydroxide, calcium carbonate, calcium bicarbonate and mixtures thereof. More preferably, the calcium hydroxide. The source of the component (c) is not particularly limited in the present application, and commercially available products well known to those skilled in the art can be used.

[0017] The calcium compound is in a powder form. The powder has a particle size of 10 nm to 200 μm, and further preferably 100 μm.

[0018] The component (d) can be selected from niobium pentoxide, niobium trioxide, niobium dioxide, niobium monoxide, niobium sulfide, niobium oxalate, niobium carbide NbC, niobium nitride NbN and mixtures thereof. More preferably, the niobium pentoxide. The source of the component (d) is not particularly limited in the present application, and commercially available products well known to those skilled in the art can be used.

[0019] The chemical formula of the said niobium pentoxide is: Nb2O5, the chemical formula of the said niobium dioxide is: NbO2, the chemical formula of the said niobium trioxide is: Nb2O3, the chemical formula of the said niobium monoxide is: NbO, the chemical formula of the said niobium sulfide is: NbS2, the chemical formula of the said niobium oxalate is: C 10 H5NbO 20 The chemical formula of the said niobium carbide is: NbC, and the chemical formula of the said niobium nitride is: NbN.

[0020] The said niobium compound is in the form of powder, and the particle size of the powder is 10-300 nm, and is further preferably 200 nm. This can significantly improve the biocompatibility and antibacterial performance of the material.

[0021] The said component (e) can be selected from zirconium oxide, barium sulfate, tantalum oxide, bismuth oxide and mixtures thereof. More preferably, it is the oxide of zirconium. The source of the said component (e) is not particularly limited in the present application, and commercially available products known to those skilled in the art can be used.

[0022] The said barrier material is in the form of powder, and the particle size of the powder is 10-300 nm, and is further preferably 200 nm.

[0023] The said component (f) can be selected from glycerol, propylene glycol, polyethylene glycol, ethylene glycol, ethanol, silicone oil, clove oil, polyethylene glycol, animal oil, vegetable oil and mixtures thereof. Component (f) is an anhydrous liquid component, which can act as a solvent to promote uniform mixing of various components and form a stable paste.

[0024] The said component (g) can be selected from one or more of cellulose and its derivatives, such as carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, etc. Component (g) can interweave to form a certain network structure, which can hinder the flow of various components and achieve thickening effect. The source of the said component (g) is not particularly limited in the present application, and commercially available products known to those skilled in the art can be used.

[0025] The said component (g) is in the form of crystal, and the particle size is 10-300 nm, and is further preferably 200 nm.

[0026] The total mass percentage of the said component (a), component (b), component (c), component (d), component (e) and component (g) in the said filling agent is 60-95%, and is preferably 70-85%. The percentage of the said component (f) in the total mass of the said filling agent is 5-40%, and is preferably 15-30%.

[0027] Specifically, it can be:

[0028] a: 45.5%, b: 1%, c: 3%, d: 2.5%, e: 19.5%, f: 28%, g: 0.5%.

[0029] or: a: 45.5%, b: 1%, c: 3%, d: 5%, e: 17%, f: 28%, g: 0.5%.

[0030] The premixed calcium silicate-niobium compound composite root canal filling agent provided by the present application is prepared by a method comprising the following steps:

[0031] The powder of the calcium silicate compound, the powder of the phosphate compound, the powder of the calcium compound, the powder of the niobium oxide compound, and the powder of the barrier material are uniformly mixed with the water-miscible non-aqueous phase solvent by ball milling, and then the mixed paste is transferred to a medical syringe, and the premixed calcium silicate-niobium compound composite root canal filling agent is obtained after sterilization and packaging. Thus, it can be directly injected in clinical application, and is a relatively ideal filling agent in the treatment of dental pulp disease.

[0032] In the preparation method of the present application; the medical syringe is preferably a medical syringe equipped with a syringe hose needle, and the diameter of the needle is preferably 0.2mm-0.5mm, more preferably 0.25mm.

[0033] The application of the above-mentioned premixed calcium silicate-niobium compound composite root canal filling agent in the preparation of a root canal filling material for treating dental pulp disease also belongs to the protection scope of the present application.

[0034] Compared with traditional calcium silicate dental filling agents, the premixed calcium silicate-niobium compound composite root canal filling agent of the present application has the following advantages:

[0035] (1) Very fast solidification, which is conducive to achieving rapid and high-quality dental pulp treatment;

[0036] (2) The paste after adding the niobium component has better bioactivity than before, and is more likely to form hydroxyapatite deposits that promote osteogenesis;

[0037] (3) The antibacterial performance of the paste after adding the niobium component is further improved compared to before;

[0038] (4) The paste after adding the niobium component can promote the maturation of immature non-pulp dental root canals;

[0039] (5) No need to adjust before use, good clinical operation performance.

[0040] At the same time, the preparation method provided by the present application has simple process and mild conditions, and shows great application potential. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1Photograph of the composite root canal filling agent of Example 1;

[0042] Figure 2 Results of the setting time test;

[0043] Figure 3 SEM photograph of the soaking test for promoting hydroxyapatite precipitation;

[0044] Figure 4 Results of the distribution of the amount of hydroxyapatite precipitation;

[0045] Figure 5 One of the results of the antibacterial test;

[0046] Figure 6 The second of the results of the antibacterial test;

[0047] Figure 7 Results of the animal experiment. DETAILED DESCRIPTION

[0048] The present application will be further described in conjunction with specific examples, but the examples do not limit the present application in any form. Unless otherwise specified, the reagents, methods and equipment used in the present application are conventional reagents, methods and equipment in the art.

[0049] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0050] Example 1, Preparation of a composite root canal filling agent of a pre-mixed calcium silicate-niobium compound

[0051] 1. Preparation of raw materials:

[0052] The calcium silicate compound is selected from tricalcium silicate powder and dicalcium silicate powder, and the particle size is 100 μm.

[0053] The phosphate compound is selected from calcium phosphate powder, and the particle size is 100 μm.

[0054] The calcium compound is selected from calcium hydroxide powder, and the particle size is 100 μm.

[0055] The niobium oxide compound is selected from niobium pentoxide powder, and the particle size is 200 nm.

[0056] The water-miscible non-aqueous solvent is selected from polyethylene glycol-400.

[0057] The barrier material is selected from zirconium oxide powder, and the particle size is 200 nm.

[0058] The organic substance is selected from hydroxypropyl methylcellulose, which is crystalline and has a particle size of 200 nm.

[0059] 2. Preparation of the composite paste:

[0060] Weigh 1.5g of calcium silicate, 3.05g of calcium silicate, 0.1g of calcium phosphate, 0.3g of calcium hydroxide, 0.25g of niobium pentoxide, 1.95g of zirconium oxide, 2.8ml of polyethylene glycol-400, 0.05g of hydroxypropyl methyl cellulose, and stir the mixture at a temperature of 25±5°C and a humidity of <30% for 30 minutes at a stirring speed of 200-300rpm, mix thoroughly for 10 minutes, and then transfer the mixture to a medical syringe equipped with a soft injection needle to obtain a premixed calcium silicate-niobium compound composite root canal filling agent.

[0061] The obtained premixed calcium silicate-niobium compound composite root canal filling agent is a white paste (see Figure 1 ), and has very good fluidity.

[0062] Example 2, Preparation of a Premixed Calcium Silicate-Niobium Compound Composite Root Canal Filling Agent

[0063] 1. Raw material preparation:

[0064] The calcium silicate compound is selected from calcium silicate powder and calcium silicate powder, and the particle size is 100μm.

[0065] The phosphate compound is selected from calcium phosphate powder, and the particle size is 100μm.

[0066] The calcium compound is selected from calcium hydroxide powder, and the particle size is 100μm.

[0067] The niobium oxide compound is selected from niobium pentoxide powder, and the particle size is 200nm.

[0068] The water-miscible non-aqueous solvent is selected from polyethylene glycol-400.

[0069] The barrier material is selected from zirconium oxide powder, and the particle size is 200nm.

[0070] The organic substance is selected from hydroxypropyl methyl cellulose, which is crystalline and has a particle size of 200nm.

[0071] 2. Preparation of the composite paste:

[0072] Example 1: 1.5 g dicalcium silicate, 3.05 g tricalcium silicate, 0.1 g calcium phosphate, 0.3 g calcium hydroxide, 0.5 g niobium pentoxide, 1.7 g zirconium oxide, 2.8 ml polyethylene glycol-400, 0.05 g hydroxypropyl methylcellulose, were weighed into a glass container and mixed mechanically with a stainless steel stirrer for 10 min until the components were homogeneously distributed. The homogeneity of the mixture was checked by visual inspection and sampling. After confirmation of homogeneity, the mixture was transferred into a medical syringe equipped with a 0.25 mm diameter injection hose needle to obtain the pre-mixed calcium silicate-niobium compound composite root canal filling material.

[0073] The resulting pre-mixed calcium silicate-niobium compound composite root canal filling material was prepared as a white paste.

[0074] Test Example

[0075] Paste preparation:

[0076] Test group: Example 1 (2.5 wt% Nb), Example 2 (5 wt% Nb) to prepare the obtained pre-mixed calcium silicate-niobium compound composite root canal filling material.

[0077] Control group (Bio SP): 0.15 g dicalcium silicate, 0.305 g tricalcium silicate, 0.1 g calcium phosphate, 0.3 g calcium hydroxide, 22 g zirconium oxide, 2.8 ml polyethylene glycol-400, 0.05 g hydroxypropyl methylcellulose were weighed into a glass container and mixed mechanically with a stainless steel stirrer for 10 min. The mixture was then transferred into a medical syringe equipped with an injection hose needle to obtain the pre-mixed calcium silicate-niobium compound composite root canal filling material preparation. The sources and qualities of the raw materials were the same as in Example 1 and Example 2.

[0078] Test Example 1, setting time test:

[0079] The present study followed the test method specified in the industry standard YY0717-2009. First, the prepared paste was filled into a hydrated gypsum mold. Subsequently, the mold was placed in a constant temperature and humidity chamber maintained at 37°C and 95% relative humidity. During the setting process, the setting state was evaluated using a penetrometer, and the material setting time was recorded under conditions of 25°C / 50% humidity. The penetrometer was equipped with a flat-ended plunger with a mass of 100g ± 0.5g, a diameter of 2mm ± 0.1mm, and a cylindrical shape with a sharp tip length of at least 5mm. The time was recorded from the end of mixing until no indentation was observed with the naked eye, and a statistical graph was made (see Figure 2 ).

[0080] The results showed that the filling material containing niobium pentoxide had a shorter setting time.

[0081] Test Example 2: Immersion test of cured composite paste to promote hydroxyapatite precipitation:

[0082] The prepared premixed calcium silicate-niobium compound composite root canal filling agent was mixed evenly with deionized water at a solid-liquid ratio of 0.5 mL / g and then placed in the solution. Cylindrical samples were prepared using a cylindrical stainless steel mold and placed in a cell culture incubator at 37°C for 7 days. After dehydration with ethanol and drying, the samples were immersed in SBF solution with a surface area to SBF volume ratio of 10:1. Every 48 hours, 25 vol% SBF was aspirated and replenished with an equal amount of fresh SBF. The concentrations of calcium, silicon, niobium, and copper ions in the SBF solution were measured by ICP at 1, 3, 7, 14, 21, and 28 days of immersion. The surface properties of the samples after 1, 3, and 7 days of immersion were analyzed by SEM and energy dispersive spectroscopy (EDX). The amount of phosphate deposition on the surface was analyzed by Raman spectroscopy.

[0083] The results showed that fillers containing niobium pentoxide had a better ability to promote surface phosphate precipitation (see...). Figures 3-4 ).

[0084] Test Example 3: Antibacterial Test

[0085] Remove cryovials containing *Escherichia coli*, *Staphylococcus aureus*, and *Enterococcus faecalis* from the -80°C freezer and immediately place them in a 37°C water bath. Once the bacterial culture in the cryovials has completely thawed, use aseptic techniques to inoculate the culture into an appropriate amount of BHI liquid medium. Incubate the medium at 37°C for 18-24 hours to ensure the bacteria are fully recovered and growing well, restoring their normal physiological state and metabolic activity. Simultaneously, prepare and cool-solidify agar plates before the experiment, ensuring they are at a suitable temperature and condition for subsequent bacterial culture spreading.

[0086] The experimental samples were divided into three groups: a blank control group without any samples, Example 1 group, and Example 2 group.

[0087] Weigh 0.5g of each sample and place them in an autoclave. Treat the samples at 120℃ for 30 minutes to ensure they are sterile. Then place the sterilized samples in a pre-prepared 48-well plate.

[0088] Take the revived bacterial culture and perform appropriate serial dilutions using PBS buffer. Adjust the bacterial concentration precisely to 10⁻⁶ using a turbidimetric method. 6 Approximately CFU / ml, ensuring the accuracy and consistency of bacterial concentration.

[0089] Using a sterile pipette, 1 ml of the adjusted concentration of bacterial solution was added to the wells of three 48-well plates, respectively, to ensure that the bacterial solution was evenly distributed in each well, and the plate was gently shaken to allow the bacterial solution to fully contact the sample.

[0090] The 48-well plate with the added bacterial solution was placed in a suitable incubation environment for 5 hours to allow the bacteria in the bacterial solution to fully interact with the sample. After incubation, 20 μl of the bacterial solution in each well was carefully aspirated using a sterile pipette and dropped onto the surface of a previously prepared sterile agar medium plate. The bacterial solution was evenly coated on the surface of the agar plate using a sterile glass ball rolling method, so that the bacteria in the bacterial solution were evenly distributed on the agar plate. The coated culture dish was placed in a 37°C constant temperature incubator and incubated for 24 hours to promote the full growth and development of the bacteria, while preventing the condensation water droplets on the culture dish cover from affecting the growth of the colonies.

[0091] After the incubation, the culture dish was removed from the incubator and carefully observed under good lighting conditions for the growth of colonies in each group of culture dishes. The colonies in each group of culture dishes were accurately counted using a colony counter, and the inhibition rate of the material on the bacteria was calculated based on the counting results.

[0092] The results showed that the filling agent containing niobium pentoxide had better antibacterial ability (see Figures 5-6 ).

[0093] Test Example 4, Animal Experiment

[0094] To verify the effect of the application in root canal filling treatment, an animal experiment was conducted to verify the prepared pre-mixed calcium silicate-niobium compound composite root canal filling agent.

[0095] Male beagle dogs were selected, which were in good growth and development, with complete permanent dentition. All animals were cleaned and disinfected with 2% iodine tincture after general anesthesia, and the iodine was removed with 75% alcohol. Strict aseptic operation was performed. The mandibular third premolar was selected as the experimental tooth, the occlusal surface was opened, the pulp chamber was removed, the pulp was completely removed, the working length was determined with #15 K file, and the H file was expanded to #40. The root canal was rinsed with physiological saline and 2.5% sodium hypochlorite every time the file was changed, and then dried. The filling agent prepared in Examples 1-2 was used to fill the root canal with gutta-percha points, which served as two experimental groups. The Bio SP group (0wt% Nb) in the paste preparation stage was used as the paste group without the addition of Nb component in the animal experiment, and the Contorl group was the simple gutta-percha point without paste. The cavity on the occlusal surface was lined with glass water gate, and the eighth generation 3M light-cured resin was used to indirectly cover the pulp.

[0096] The animals were fed with soft food within one week after the operation, and were injected with antibiotics for one week. Whether the animals had abnormal daily activities and normal food intake after the operation was observed. The mental state, feces and oral tissue of the animals were observed regularly. The animals were sacrificed for sampling three months after the root canal treatment.

[0097] The image observation study showed that the left and right third premolars (L and R) of the experimental group were significantly better than the control group in the growth of root canal root length and the increase of root canal wall thickness (see Figure 7 ).

[0098] It can be seen from the above experiments that, by adding the Nb compound, the calcium silicate and niobium oxide compounds in the filling agent can construct a biphasic composite self-curing system, accelerate the curing time, and the introduction of Nb can improve the biological activity and promote the deposition of hydroxyapatite for osteogenesis; and the antibacterial property is further improved, so that when applied to pulp filling, it can promote the further maturation of immature pulpless root canals; significantly improve the treatment effect. Moreover, the filling agent of the embodiment of the present application does not need to be adjusted before use, and has good clinical operation performance.

[0099] The technical features of the above-described embodiments can be combined arbitrarily, and to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present disclosure.

[0100] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the protection scope of the present patent should be subject to the appended claims.

Claims

1. A premixed calcium silicate-niobium compound composite root canal filling agent, characterized in that: include: (a) calcium silicate compounds, (b) phosphate compounds, (c) calcium compounds, (d) niobium compounds, (e) radiation-shielding materials, (f) water-miscible non-aqueous solvents, and (g) organic matter, wherein components (a), (b), (c), (d), (e), and (g) together account for 60% to 95% of the total mass of the filler, and component (f) accounts for 5% to 40% of the total mass of the filler.

2. The composite root canal filling agent according to claim 1, characterized in that, The component (a) is selected from one or more of tricalcium silicate, dicalcium silicate and monocalcium silicate; Preferably, component (a) is selected from two powders of tricalcium silicate, dicalcium silicate and monocalcium silicate, in a ratio of 1.8:1 to 2.2:

1.

3. The composite root canal filling agent according to claim 1, characterized in that, The component (b) is selected from one or more of the following: calcium phosphate, magnesium phosphate, sodium phosphate, zinc phosphate, iron phosphate, potassium phosphate, nickel phosphate, zirconium phosphate, phosphoric acid, and organometallic phosphates; The component (b) is a powder with a particle size of 10 nm to 200 μm, more preferably 100 μm.

4. The composite root canal filling agent according to claim 1, characterized in that, The component (c) is selected from one or more of calcium hydroxide, calcium carbonate, and calcium bicarbonate; The component (c) is a powder with a particle size of 10 nm to 200 μm, more preferably 100 μm.

5. The composite root canal filling agent according to claim 1, characterized in that, The component (d) is selected from one or more of the following: niobium pentoxide, niobium trioxide, niobium dioxide, niobium monoxide, niobium sulfide, niobium oxalate, niobium carbide, and niobium nitride; The component (d) is a powder with a particle size of 10 nm to 300 μm, more preferably 100 μm.

6. The composite root canal filling agent according to claim 1, characterized in that, The component (e) is selected from one or more of the following: zirconium oxide, barium sulfate, tantalum oxide, and bismuth oxide; The component (c) is a powder with a particle size of 10 nm to 300 μm, more preferably 100 μm.

7. The composite root canal filling agent according to claim 1, characterized in that, The component (f) is selected from one or more of the following: glycerin, propylene glycol, polyethylene glycol, ethylene glycol, ethanol, silicone oil, clove oil, polyethylene glycol, animal oil, and vegetable oil.

8. The composite root canal filling agent according to claim 1, characterized in that, The component (g) may be selected from one or more of cellulose and its derivatives; The component (g) is a crystalline powder with a particle size of 10 nm to 300 μm, more preferably 100 μm.

9. The method for preparing the composite root canal filling agent according to any one of claims 1-8, characterized in that, The process includes the following steps: uniformly mixing components (a), (b), (c), (d), (e), (f), and (g) using a ball mill; then transferring the mixed paste into a medical syringe; and finally packaging and sterilizing it to obtain the composite root canal filling agent.

10. The use of the composite root canal filling agent according to any one of claims 1-8 in the preparation of root canal filling materials for the treatment of pulpitis.

Images