Biological ceramic dental pulp sealing material with one-way permeation function and preparation method of biological ceramic dental pulp sealing material

Abstract

The invention discloses a biological ceramic dental pulp sealing material with a one-way permeation function and a preparation method of the biological ceramic dental pulp sealing material. The material comprises powder and liquid, the powder is prepared from the following components in parts by mass: 10 to 30 parts of Ca3SiO5, 30 to 50 parts of Ca2SiO4, 1 to 30 parts of Ca3 (PO4) 2, 3 to 45 parts of a radiation inhibitor, 5 to 10 parts of a pore forming agent, 1 to 9 parts of nano SiO2 and 1 to 10 parts of strontium silicate. The material not only has good sterility and excellent pressure resistance to oral bacteria, but also has a one-way permeation function compared with a traditional sealing material, so that gas and body fluid in a medullary cavity can permeate, and meanwhile, the bacteria in the oral cavity cannot enter the medullary cavity; and a good environment is provided for treatment and recovery of dental pulp tissues.

Description

Technical Field

[0001] The present invention relates to a bioceramic dental pulp sealing material and a preparation method thereof, in particular to a bioceramic dental pulp sealing material with a one-way permeability function and a preparation method thereof, belonging to the technical field of dental medical materials. Background Art

[0002] Calcium silicate-based bioceramics are ceramic materials used in medicine and dentistry. Due to their biocompatibility, non-toxicity, resistance to shrinkage, and chemical stability in biological environments, they are widely used in dental implants, endodontics, alveolar augmentation, and maxillofacial surgery. Bioceramic sealants have demonstrated excellent apical sealing properties and marginal adaptability in the treatment of endodontic and periapical diseases.

[0003] Calcium hydroxide pulp capping material, a traditional endodontic treatment option, has demonstrated the ability to promote dentin bridge formation and inhibit bacterial growth during direct pulp capping. Its alkaline environment effectively neutralizes acidic substances in the inflamed area, providing favorable conditions for pulp healing. While calcium hydroxide pulp capping material is easy to use and cost-effective in clinical applications, its strong alkalinity can cause coagulative necrosis of exposed pulp tissue, leading to complications such as root canal calcification, obstruction, and resorption, resulting in pulp capping failure. Calcium silicate-based bioceramic pulp capping material, an advanced bioceramic pulp capping agent, demonstrates excellent biocompatibility and sealing properties during direct pulp capping. While promoting dentin bridge formation, it provides an environment highly compatible with pulp tissue, facilitating the attachment and growth of pulp cells. Furthermore, this material can complete pulp capping in a single procedure, simplifying the treatment process, and its radiopacity facilitates visualization on X-rays.

[0004] However, common calcium silicate-based bioceramic sealing materials lack unidirectional permeability. While they offer excellent sealing properties, this is disadvantageous during the treatment of pulpitis. In a completely closed pulp environment, fluids produced by cellular metabolism cannot be excreted, increasing the pressure in the pulp, causing pain and further exacerbating inflammation. Therefore, a bioceramic sealing material with unidirectional permeability is urgently needed to meet the environmental requirements of pulpitis treatment and provide a more favorable treatment environment. Summary of the Invention

[0005] In response to the problems existing in bioceramic dental pulp sealing materials, the first object of the present invention is to provide a bioceramic dental pulp sealing material with a one-way permeability function. This material not only has good sterilization properties against oral bacteria and can meet the mechanical properties such as compressive resistance and hardness required of dental pulp sealing materials, but also has a one-way permeability function compared to traditional sealing materials in the early stage of treatment, which allows the gas and body fluids in the pulp cavity to penetrate while preventing bacteria in the oral cavity from entering the pulp cavity. In the later stage of treatment, the components in the dental pulp sealing material continue to react, gradually closing the pore channels and isolating bacteria, preventing them from entering the dental pulp cavity. The decompression and sealing effects can be achieved in one treatment process, providing a good environment for the treatment and recovery of dental pulp tissue.

[0006] The second object of the present invention is to provide a method for preparing a bioceramic dental pulp sealing material with a one-way permeability function, which has the advantages of simple process and short flow.

[0007] In order to achieve the above technical objectives, the present invention provides a bioceramic dental pulp sealing material with a one-way penetration function, which includes a powder and a liquid; the powder includes the following components by mass: 10-30 parts of Ca3SiO5, 30-50 parts of Ca2SiO4, 1-30 parts of Ca3(PO4)2, 3-45 parts of a radiopaquer, 5-10 parts of a pore-forming agent, 1-9 parts of nano-SiO2, and 1-10 parts of strontium silicate; the initial pore size of the pore structure of the bioceramic dental pulp sealing material is 0.1-20 μm, and the pore size of the pore structure is less than or equal to 0.2 μm after a use time of greater than or equal to 30 days.

[0008] Traditional endodontic sealing materials lack pores after curing, and once the surface CH is consumed, they are unable to further increase hydroxide ions, so their high pH environment cannot be maintained for long periods of time. However, the present invention adds a certain pore-forming agent to the endodontic sealing material, which synergizes with the various components to construct a unique pore structure, giving it the comprehensive properties of unidirectional permeability, excellent sterilization, and high strength. Specifically, the C3S (Ca3SiO5) and C2S (Ca2SiO4) in the powder continuously solidify to form a three-dimensional pore structure and CH (Ca(OH)2). Simultaneously, during the curing process, the pore-forming agent continuously dissolves, ensuring the material has sufficient inherent pores and a narrow pore size distribution. Furthermore, the pore structure is interconnected, facilitating the discharge of gases and fluids from the pulp cavity. In addition, the nano-SiO2 in the powder also plays a key role. On the one hand, it can refine the pores in the bioceramic pulp capping material through its filling effect, and react with Ca(OH)2 to increase the CSH gel content, reducing the loose and porous hexagonal plate-like Ca(OH)2 crystals, promoting the conversion of Ca(OH)2 to a columnar form and reducing crystal orientation, thereby further reducing porosity and optimizing pore size distribution. On the other hand, the nano-SiO2 reduces the defects of the large pores in the calcium silicate-based pulp capping material through its filling effect, making the microstructure more uniform. It can form a strong interfacial bond with the calcium silicate matrix to improve overall performance, and it also increases the density of the calcium silicate hydrate (CSH) gel. The high-density CSH gel has a strong pore-filling effect, improving the pore structure of the calcium silicate-based pulp capping material and reducing the possibility of bacteria passing through excessively large pores formed due to the dissolution of the pore-forming agent during the curing process. At the same time, Ca3(PO4)2 can react with Ca(OH)2 to form hydroxyapatite, which can also increase the strength of the sealing material after solidification. The addition of a small amount of strontium silicate regulates the solidification rate of the pulp capping material, which is beneficial to adjust the solidification time. However, if its dosage is too high, it will lead to a decrease in strength after solidification.

[0009] The mechanism by which the dental pulp sealing material of the present invention has long-lasting and good antibacterial and bactericidal properties is that: during the initial hydration process of use, C3S will form interconnected pores under the synergistic effect of the pore-forming agent. The pores are evenly distributed and have large pore diameters, ensuring permeability during dental pulp treatment. During this period, the bioceramic dental pulp sealing material will continuously generate Ca(OH)2 due to its hydration mechanism, continuously forming a strong alkaline environment inside and near the pores of the bioceramic dental pulp material. This is an extremely harsh living environment for bacteria in the oral cavity, and bacteria cannot survive in such an environment. In the subsequent process, C2S continues to react, and during the hydration process, CSH is generated to slowly fill the pores. After 30 days, the pores formed in the early stage of the bioceramic dental pulp material are basically closed, leaving only some tiny micropores, which gradually close the bioceramic dental pulp material and form a relatively closed pulp cavity environment, thereby protecting the pulp cavity.

[0010] Ca3SiO5 reacts with water in the liquid to form calcium silicate hydrate and calcium hydroxide, which can release hydroxide ions in their pore environment.

[0011] In the present invention, the dosage of pore-forming agent and nano-SiO2 needs to be controlled. If the dosage of pore-forming agent is too high, the porosity and pore size will be too large, which will cause bacteria to pass through and the strength of the sealing material will be seriously reduced. If the dosage of pore-forming agent is too low, no connected pores can be formed, resulting in the inability to achieve the osmotic pressure reduction function; if the dosage of nano-SiO2 is too high, the material will not be able to solidify, and if the dosage is too low, the pore size will be difficult to control and the strength will be reduced.

[0012] As a preferred embodiment, the pore-forming agent includes sodium chloride and / or sodium bicarbonate. The pore-forming agent selected in the present invention is inexpensive, easily dispersed, has good biocompatibility, and does not cause irritation or toxicity to dental pulp tissue. During the curing process, sodium chloride and sodium bicarbonate dissolve to form a interconnected pore structure with sufficient porosity and a narrow pore size distribution, which facilitates the drainage of body fluids from the oral cavity.

[0013] As a preferred solution, the particle size of the Ca3SiO5 is 0.4-30 μm, the particle size of the Ca2SiO4 and Ca3(PO4)2 are both 0.4-30 μm, the particle size of the radiation barrier and strontium silicate are both 0.02-20 μm, and the particle size of the pore-forming agent is 10-30 μm. The different particle sizes of the various substances in the powder have certain differences in the antibacterial properties of the bioceramic sealing material. The smaller the average particle size of the material, the more obvious the antibacterial effect on bacteria. This is because the smaller the powder particle size, the more OH can be released. -1 , generating more Ca(OH)2 in a shorter period of time, thereby raising the pH of the entire environment and destroying bacterial biofilms. Within the particle size range selected by the present invention, a favorable pH environment is maintained while ensuring that the bioceramic dental endodontic sealant maintains a continuous, unidirectional permeable pore system during initial use.

[0014] As a preferred embodiment, the radiation barrier comprises 1-15 parts by weight of ZrO2, 1-15 parts by weight of BaSO4, and 1-15 parts by weight of Ta2O5. These three radiation barrier agents selected in the present invention all have high X-ray absorption coefficients, allowing for clear observation of material boundaries on X-ray films, facilitating dental observation. Furthermore, all three radiation barrier agents exhibit excellent biocompatibility and enhance the mechanical properties of bioceramic materials to varying degrees.

[0015] As a preferred embodiment, the liquid comprises a liquid alcohol compound, water, cellulose, and a surfactant. Furthermore, the liquid alcohol compound comprises at least one of propylene glycol, ethylene glycol, liquid polyethylene glycol, and glycerol. The liquid alcohol compound selected in the present invention has good stability, enables uniform mixing of the powder, and has good compatibility with water. An appropriate amount of surfactant can enhance the dispersibility of the powder, allowing for more uniform mixing; and cellulose forms a gel in water to function.

[0016] As a preferred solution, the mass ratio of the powder to the liquid is (2.5-4):1. More preferably, the mass ratio of the powder to the liquid is (3.5-4):1.

[0017] As a preferred solution, the bioceramic dental pulp sealant is used in a pH environment of 11 to 13. Because Enterococcus faecalis, a representative bacterial species in the oral environment, is inhibited from growing at a pH of 11 and dies directly at a pH greater than 11.5, the bioceramic dental pulp sealant of the present invention has a good sterilization effect on Enterococcus faecalis, further enhancing the therapeutic effect of pulpitis.

[0018] The present invention also provides a method for preparing a bioceramic dental pulp sealant with unidirectional permeability. This method comprises separately preparing a powder and a liquid according to the designed components, then adding the powder to the liquid and mixing them. This preparation method, which involves separately preparing the powder and liquid, offers advantages such as a simple process and a short flow.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] (1) The bioceramic dental pulp sealing material with one-way permeability provided by the present invention proposes an idea to break the inherent process. By adding pore-forming agents and nano-silica and calcium silicate-based materials to collaboratively construct a special pore structure, the material not only has good sterilization properties for oral bacteria and can meet the mechanical properties such as compressive resistance and hardness required of dental pulp sealing materials, but also has one-way permeability compared with traditional sealing materials, which can meet the requirements of gas and body fluids in the pulp cavity while preventing bacteria in the oral cavity from entering the pulp cavity, providing a good environment for the treatment and recovery of dental pulp tissue.

[0021] (2) The fine pore structure of the dental pulp sealing material provided by the present invention prevents oral bacteria from passing through, while allowing oral body fluids to pass through. During the treatment and recovery process, the dental pulp will not be inflamed due to increased pressure in the dental pulp environment caused by sealing.

[0022] (3) The material of the present invention maintains excellent antibacterial properties, one-way permeability function and high strength performance within 30 days.

[0023] (4) The components used in the bioceramic dental pulp sealing material of the present invention have excellent biocompatibility, do not cause additional toxic reactions, and are conducive to the growth and repair of dental pulp tissue.

[0024] (5) The preparation method of the present invention has a simple process and a short flow, which is conducive to industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 (a) is the compressive strength of Example 1 and Comparative Examples 1 to 4 after curing for seven days, Figure 1 (b) is the porosity of Example 1 and Comparative Examples 1-4 after curing for seven days, wherein the curing was performed according to the method in Standard No. YY 0717-2023.

[0026] Figure 2 Figures 2 and 3 are cross-sectional SEM images of a bioceramic dental pulp sealant with one-way permeability according to the present invention. (a) and (b) are SEM images of the bioceramic dental pulp sealant of Example 1 after curing for 7 days and 35 days, respectively; (c) and (d) are SEM images of the bioceramic dental pulp sealant of Comparative Example 1 after curing for 7 days and 35 days, respectively. Curing was performed according to the method of Standard No. YY 0717-2023.

[0027] Figure 3 The pH value change curves of Example 1 and Comparative Example 1 of the present invention at different times are shown. The pH test was performed according to the method 6.4 in standard number YY / T 0824-2011, and the solution was replaced after each measurement, and the pH was measured subsequently. DETAILED DESCRIPTION

[0028] The following further illustrates the technical solution of the present invention in conjunction with specific examples. However, it should be noted that the scope of protection of the present invention is not limited to the enumerated embodiments. It should be noted that the embodiments shown here are for illustrative purposes only. Other embodiments that can be derived by those skilled in the art based on the core technical solution of the present invention without creative work are all within the scope of protection of the claims of this patent.

[0029] Unless otherwise specified, all raw materials, reagents, instruments and equipment involved in the present invention can be obtained through commercial channels or prepared using existing methods.

[0030] Example 1

[0031] The total mass of the powder is 100g, wherein: 15wt% Ca3SiO5 has an average particle size of 0.40μm, 40wt% Ca2SiO4 has an average particle size of 0.70μm, 10wt% Ca3(PO4)2 has an average particle size of 0.80μm, 7wt% ZrO2 has an average particle size of 0.30μm, 5wt% BaSO4 has an average particle size of 0.65μm, 5wt% Ta2O5 has an average particle size of 0.45μm, 5wt% strontium silicate has an average particle size of 0.25μm, 7wt% NaCl and 3wt% The average particle size of 3wt% NaHCO3 is 10μm, and the average particle size of 3wt% SiO2 is 35nm; the mass of the liquid is 25g, and the components are propylene glycol, ethylene glycol, polyethylene glycol, glycerol, water, cellulose, and sodium dodecylbenzenesulfonate, among which the mass percentages of propylene glycol, ethylene glycol, polyethylene glycol, glycerol, water, cellulose, and sodium dodecylbenzenesulfonate are 20%: 15%: 15%: 10%: 39.2%: 0.4%: 0.4%.

[0032] Powder and liquid were prepared according to the designed components. The prepared powder was then added to the liquid at a mass ratio of 4:1, and the mixture was evenly mixed by stirring and ball milling to obtain a bioceramic dental pulp sealing material with unidirectional permeability.

[0033] Example 2

[0034] Calculated based on the total mass of the powder being 100 g, the powder comprises: 15 wt% Ca3SiO5 having an average particle size of 15 μm, 40 wt% Ca2SiO4 having an average particle size of 12 μm, 10 wt% Ca3(PO4)2 having an average particle size of 10 μm, 7 wt% ZrO2 having an average particle size of 10 μm, 5 wt% BaSO4 having an average particle size of 12 μm, 5 wt% Ta2O5 having an average particle size of 13 μm, 5 wt% strontium silicate having an average particle size of 15 μm, 7 wt% NaCl and 3 wt% NaHCO3 having an average particle size of 20 μm, and 3 wt% SiO2 having an average particle size of 35 nm; the components and proportions of the liquid are the same as those in Example 1.

[0035] The preparation steps and conditions were the same as those in Example 1 to obtain a bioceramic dental pulp sealing material with unidirectional permeability.

[0036] Example 3

[0037] The difference between this embodiment and Example 1 is that: based on the total mass of the powder being 100 g, the present embodiment comprises: 15 wt% Ca3SiO5 having an average particle size of 28 μm, 34 wt% Ca2SiO4 having an average particle size of 30 μm, 10 wt% Ca3(PO4)2 having an average particle size of 25 μm, 7 wt% ZrO2 having an average particle size of 20 μm, 5 wt% BaSO4 having an average particle size of 15 μm, 5 wt% Ta2O5 having an average particle size of 18 μm, 5 wt% strontium silicate having an average particle size of 20 μm, 7 wt% NaCl and 3 wt% NaHCO3 having an average particle size of 30 μm, and 9 wt% SiO2 having an average particle size of 35 nm; the components and proportions of the liquid are the same as those in Example 1.

[0038] The preparation steps and conditions were the same as those in Example 1 to obtain a bioceramic dental pulp sealing material with unidirectional permeability.

[0039] Example 4

[0040] The difference between this embodiment and embodiment 1 is that the mass ratio of powder to liquid is 3.5:1, and the other steps and conditions are the same, thereby obtaining a bioceramic dental pulp sealing material with unidirectional permeability function.

[0041] Example 5

[0042] The difference between this embodiment and embodiment 1 is that the mass ratio of powder to liquid is 3:1, and the other steps and conditions are the same, thereby obtaining a bioceramic dental pulp sealing material with unidirectional permeability function.

[0043] Example 6

[0044] The difference between this embodiment and embodiment 1 is that the mass ratio of powder to liquid is 2.5:1, and the other steps and conditions are the same, thereby obtaining a bioceramic dental pulp sealing material with unidirectional permeability function.

[0045] Example 7

[0046] The difference between this embodiment and embodiment 1 is that the content of NaCl is 10 wt %, the content of NaHCO 3 is 0 wt %, and the remaining steps and conditions are the same, thereby obtaining a bioceramic dental pulp sealing material with unidirectional permeability function.

[0047] The pore structure changes of the bioceramic dental pulp sealing materials with unidirectional permeability prepared in Examples 2 to 7 are the same as those of the sealing material prepared in Example 1. Figure 2 (a) and Figure 2 (b), and the pH value can be maintained above 11.5 during the curing period of 0 to 35 days. The compressive strength, porosity, and pH value of the bioceramic dental endodontic sealing materials with unidirectional permeability prepared in Examples 2 to 7 are shown in Table 1.

[0048]

[0049] Comparative Example 1

[0050] The difference between this comparative example and Example 1 is that the content of NaCl and NaHCO3 is 0wt%, the content of Ca3SiO5 is 25wt%, and the remaining steps and conditions are the same to obtain a bioceramic dental pulp sealing material.

[0051] Depend on Figure 1 and Figure 3 From the data comparison, it can be seen that when the pore-forming agent is added, the compressive strength of the prepared bioceramic dental pulp sealing material decreases slightly, but the porosity increases significantly. More importantly, the sealing material of Example 1 can not only maintain a higher pH concentration in the presence of the pore-forming agent, but also maintain a high pH sterilization environment for a long time. This proves that the pore-forming agent added in the present invention can produce a good synergistic effect with the added Ca3SiO5 and Ca2SiO4.

[0052] Figure 2 (a) and Figure 2 (b) are SEM morphologies of the bioceramic dental pulp sealant of Example 1 after curing for 7 days and 35 days, respectively. It can be seen that the sealing material of the present invention has channels with relatively large pores in the early stage of use, which ensures the permeability of the dental pulp sealant during pulp treatment. In the later stage of use, the pore structure is filled with pores due to the hydration of C2S, gradually sealing the bioceramic dental pulp material and forming a relatively closed pulp cavity environment. Figure 2 (c) and Figure 2 (d) SEM morphology images of the bioceramic dental pulp sealing material of comparative example 1 after curing for 7 days and 35 days, respectively. The results show that when no pore-forming agent is added, the initial porosity is low and there is no large pore structure. It is a conventional fully sealed material and does not have a unidirectional permeability function.

[0053] Comparative Example 2

[0054] The difference between this comparative example and Example 1 is that the content of SiO2 is 0wt%, the content of Ca3SiO5 is 18wt%, and the remaining steps and conditions are the same to obtain a bioceramic dental pulp sealing material.

[0055] Comparative Example 3

[0056] The difference between this comparative example and Example 1 is that the average particle size of SiO2 is 1 μm, and the other steps and conditions are the same to obtain a bioceramic dental pulp sealing material.

[0057] Comparative Example 4

[0058] The difference between this comparative example and Example 1 is that the content of Ca3SiO5 is 40wt% and the content of Ca2SiO4 is 15wt%. The remaining steps and conditions are the same to obtain a bioceramic dental pulp sealing material.

[0059] Figure 1 (a) and Figure 1 (b) shows that when SiO2 is not added or the average particle size of SiO2 is too large, or the amount of Ca3SiO5 is too high and the amount of Ca2SiO4 is too low, it will have an adverse effect on the strength of the sealing material and cannot meet the application requirements.

Claims

1. A bioceramic dental pulp sealing material with one-way permeability, characterized by: The bioceramic dental pulp sealing material comprises a powder and a liquid; the powder comprises the following components by mass: 10 to 30 parts of Ca3SiO5, 30 to 50 parts of Ca2SiO4, 1 to 30 parts of Ca3(PO4)2, 3 to 45 parts of a radiation barrier, 5 to 10 parts of a pore-forming agent, 1 to 9 parts of nano-SiO2, and 1 to 10 parts of strontium silicate; the initial pore size of the pore structure of the bioceramic dental pulp sealing material is 0.1 to 20 μm, and the pore size of the pore structure is less than or equal to 0.2 μm after being used for 30 days or more.

2. The bioceramic dental pulp sealing material with one-way permeability according to claim 1, characterized in that: The pore former includes sodium chloride and / or sodium bicarbonate.

3. The bioceramic dental pulp sealing material with one-way permeability according to claim 1 or 2, characterized in that: The particle size of the Ca3SiO5 is 0.4-30 μm, the particle sizes of Ca2SiO4 and Ca3(PO4)2 are both 0.4-30 μm, the particle sizes of the radiation barrier and strontium silicate are both 0.02-20 μm, and the particle size of the pore-forming agent is 10-30 μm.

4. The bioceramic dental pulp sealing material with one-way permeability according to claim 3, characterized in that: The radiation-blocking agent consists of 1 to 15 parts by weight of ZrO2, 1 to 15 parts by weight of BaSO4 and 1 to 15 parts by weight of Ta2O5.

5. The bioceramic dental pulp sealing material with one-way permeability according to claim 4, characterized in that: The liquid comprises a liquid alcohol compound, water, cellulose and a surfactant.

6. The bioceramic dental pulp sealing material with one-way permeability according to claim 1, characterized in that: The mass ratio of the powder to the liquid is (2.5~4):

1.

7. The bioceramic dental pulp sealing material with one-way permeability according to claim 6, characterized in that: The pH environment in which the bioceramic dental pulp sealing material is used is 11-13.

8. The method for preparing a bioceramic dental pulp sealing material with one-way permeability according to any one of claims 1 to 7, characterized in that: The powder and liquid are prepared separately according to the designed components, and then the powder is added into the liquid to mix.

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