Preparation method of zirconia ceramic periodontal splint

Abstract

The invention provides a preparation method of a zirconia ceramic periodontal splint. The preparation method comprises the following steps: preparing ceramic slurry containing zirconia powder and an ether organic solvent; according to intraoral scanning data of the patient, designing a periodontal splint three-dimensional digital model fitting the tongue side form of the teeth of the patient; putting the ceramic slurry into ink-jet 3D printing equipment, synchronously spraying the ceramic slurry and a supporting material, printing a green body of the periodontal splint layer by layer, and generating a plurality of microcavities in the periodontal splint in the layer-by-layer printing process; carrying out high-temperature sintering on the green body to obtain a zirconia ceramic periodontal splint finished product, dispersing microcapsules in a solvent, enabling a microcapsule solution to permeate into the microcavity through vacuum impregnation, and then drying to remove the solvent so as to enable the microcapsules to be placed in the microcavity; the biocompatibility of the periodontal splint is improved, the splint adapts to specific periodontal contours of different patients, loose teeth are fixed, dentition fixation is kept, continuous and stable release of an antibacterial agent can be achieved, and periodontal infection is prevented.

Description

Technical Field

[0001] This invention relates to the field of dentistry, and in particular to a method for preparing a zirconia ceramic periodontal splint. Background Technology

[0002] A periodontal splint is an orthodontic appliance used to stabilize loose teeth. Its core function is to mechanically connect two or more teeth that are loose due to periodontal disease, or to fix these loose teeth to relatively healthy adjacent teeth, thereby forming a new functional masticatory unit. Periodontal splints can achieve the following therapeutic goals: ① Slower periodontal tissue damage: After fixation, the abnormal mobility of the teeth is eliminated, preventing the vicious cycle of "loosening-inflammation-further loosening"; ② Prevention of secondary occlusal trauma: Splint fixation prevents occlusal disorder caused by tooth displacement and avoids the occurrence of secondary occlusal trauma; ③Restoration of chewing function: By connecting multiple loose teeth into functional units, the patient's chewing efficiency is significantly improved.

[0003] Current types of periodontal splints mainly include fiber-reinforced resin splints and metal wire ligation splints, but these existing periodontal splints have at least the following problems: 1. Poor biocompatibility: Metal materials pose an allergy risk, while resin materials have relatively poor chemical stability; 2. Craftsmanship and adaptability: Traditional splints are mostly standardized or hand-bent, which have low adaptability to the individual morphology of the patient's teeth on the lingual side and poor comfort. 3. Only passively assists in treatment: Current periodontal splints only serve to mechanically fix loose teeth and cannot actively inhibit periodontal disease. Once periodontal disease progresses and affects the healthy tooth tissue around the splint, it will lead to treatment failure or require replacement of the periodontal splint. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a zirconia ceramic periodontal splint that improves the biocompatibility of periodontal splints, adapts to the specific periodontal contours of different patients, fixes loose teeth, maintains dentition stability, and enables continuous and stable release of antibacterial agents to prevent periodontal infection.

[0005] To address the aforementioned technical problems, this invention provides a method for preparing a zirconia ceramic periodontal splint, comprising the following steps: Step 1: Prepare a ceramic slurry containing zirconium oxide powder and ether-based organic solvent; Step 2: Based on the patient's intraoral scan data, design a three-dimensional digital model of a periodontal splint that fits the lingual morphology of the patient's teeth. Step 3: Place the ceramic slurry into the inkjet 3D printing equipment, spray the ceramic slurry and support material simultaneously, and print the periodontal splint green layer by layer. During the layer-by-layer printing process, several microcavities are generated inside the periodontal splint. Step 4: The green embryo is sintered at high temperature to obtain the finished zirconia ceramic periodontal splint. The microcapsules are dispersed in a solvent and impregnated under vacuum to allow the microcapsule solution to penetrate into the microcavity. Then, the solvent is removed by drying to allow the microcapsules to be placed in the microcavity.

[0006] Furthermore, the inner wall of the microcavity has a porous structure, and the interior of the microcavity is connected to the outside of the periodontal splint through the porous structure, so that the microcapsule can release antibacterial components outward through the porous structure.

[0007] Furthermore, the pore structure is distributed in a gradient from the inside to the outside, with the porosity of the part of the pore structure near the inside of the microcavity being 30%-50%, and the porosity of the part of the pore structure near the outside of the periodontal splint being less than 10%.

[0008] Furthermore, in step three, when the inkjet 3D printing equipment prints layer by layer to 50%-80% of the total volume of the microcavity, the microcavity is kept open, and the microcapsule is placed into the microcavity through the opening position.

[0009] Furthermore, the periodontal splint has a grid-like microporous structure on the surface for bonding with the teeth, the pore size of the microporous structure being 1-5 μm and the depth of the microporous structure being 5-10 μm.

[0010] Furthermore, the microcavities are spherical structures with a diameter of 50-200 μm, and several microcavities are distributed in a honeycomb pattern. The printing layer thickness of the green embryo is 20-80 μm.

[0011] Furthermore, the microcapsules are prepared by molecular encapsulation, the core material of the microcapsules is an antibacterial agent, and the wall material of the microcapsules is cyclodextrin.

[0012] Furthermore, the wall material of the microcapsule contains a pH-sensitive material, which accelerates the release of the microcapsule when the pH of the periodontal pocket is greater than 7.4.

[0013] Furthermore, the outer surface of the microcapsule is coated with a polyurethane methacrylate-based coating.

[0014] The beneficial effects of this invention are as follows: 1. Zirconia ceramic materials themselves have high fracture toughness and flexural strength, which can provide stable and reliable mechanical support for loose teeth.

[0015] 2. Zirconia is a bioinert ceramic with no risk of metal ion precipitation and low chemical solubility (measured at 27.3 μg·cm³). -²), with high biosafety (cytotoxicity grade 0, no sensitization).

[0016] 3. The bonding surface between the periodontal splint and the teeth has a grid-like microporous structure, which can significantly increase the bonding area and form a mechanical interlock with the adhesive, effectively preventing detachment.

[0017] 4. Based on the patient's oral cavity scan data, the periodontal splint is 3D printed, and the edge of the splint fits closely with the lingual shape of the teeth. The thickness can be precisely controlled, greatly reducing the feeling of a foreign body.

[0018] 5. Using 3D printing additive manufacturing, no mold is needed, and it can be directly formed, reducing material waste and processing steps. It can be adapted to the oral conditions of different patients.

[0019] 6. The microcavity and microcapsule structure allows the periodontal splint to not only provide fixation but also continuously release antibacterial agents, effectively preventing periodontal infection, providing proactive prevention, inhibiting the progression of periodontal disease, and avoiding the spread of periodontal disease to healthy teeth, thus preventing frequent replacement of the periodontal splint. Attached Figure Description

[0020] Figure 1 This is a front view of the present invention.

[0021] Figure 2 This is a top view of the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0023] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0024] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0025] like Figures 1-2 The present invention provides a method for preparing a zirconia ceramic periodontal splint, comprising the following steps: Step 1, Material Preparation: Use ceramic slurry whose main components are zirconium oxide powder (made from zirconium oxide (containing hafnium oxide and yttrium oxide) (≥99.0%), yttrium oxide (4.5%~6.0%), hafnium oxide (≤5%), and alumina (≤0.5%) through additive manufacturing technology) and ether-based organic solvents.

[0026] Step 2, 3D Modeling: The patient's oral cavity data is scanned using an oral scanner. Based on the patient's intraoral scan data, a 3D digital model of a splint that perfectly fits the lingual morphology of the teeth is designed in CAD software, avoiding the mechanical pressure on adjacent teeth caused by traditional splints.

[0027] Step 3, Additive Manufacturing: The ceramic slurry is placed into the inkjet 3D printing equipment and sprayed synchronously through dual nozzles. Liquid zirconium oxide material and support material are sprayed synchronously at a rate of hundreds of millions of drops per second to print the green plate of the periodontal splint layer by layer. During the layer-by-layer printing process, several microcavities are generated inside the periodontal splint.

[0028] Among them, a honeycomb-like microcavity network is designed inside the zirconia periodontal splint using additive manufacturing layer-by-layer stacking technology. Each microcavity is a spherical structure with a diameter of 50-200μm, which independently loads antibacterial agent microcapsules. In one embodiment of this solution, the cavity wall of the microcavity adopts a gradient distribution of pore structure. The porosity of the part of the pore structure near the outside of the periodontal splint is <10% to slow down the initial burst release, while the porosity of the part of the pore structure near the inside of the microcavity structure is 30%-50% to promote long-term sustained release. The porosity can be precisely controlled by adjusting the printing layer thickness (e.g., 20-80μm) and inkjet printing parameters.

[0029] It is worth mentioning that the microcapsule preparation method adopts molecular encapsulation, using an antibacterial agent (chlorhexidine) as the core material and cyclodextrin as the wall material. Since cyclodextrin is a cyclic molecule with a hydrophobic cavity, chlorhexidine containing the hydrophobic end enters the cavity and is reliably bound into molecular microcapsules by intermolecular forces. The surface of the microcapsule is coated with a polyurethane methacrylate-based coating to enhance the binding force with the zirconia matrix and avoid direct contact between the drug and the ceramic, which could lead to denaturation. At the same time, the microcapsules are mixed with a hydrogel precursor and then vacuum impregnated, followed by gelation in the microcavity. A temperature-responsive hydrogel is used to fill the microcavity, and changes in oral temperature trigger the swelling or contraction of the gel, thereby squeezing the microcapsules inside the microcavity to release the antibacterial agent and achieve a slow drug release effect.

[0030] Specifically, microcapsules are prepared using a molecular encapsulation method to encapsulate antibacterial agents (such as chlorhexidine) within wall materials such as cyclodextrin, forming microcapsule particles. These microcapsules are then dispersed in a solvent using a vacuum impregnation method, and finally filled into the microcavities of a zirconia ceramic clamp. The process sequence is as follows: 1. Microcapsules were first prepared using a molecular encapsulation method; 2. Disperse the prepared microcapsules in a solvent to form a suspension; 3. The microcapsule suspension is infiltrated into the microcavities of the ceramic clamp through vacuum impregnation; 4. Dry to remove solvent, completing the microcapsule insertion.

[0031] In addition, pH-sensitive materials (such as Eudragit® L100) can be added to the microcapsule wall material. When the periodontal pocket pH is greater than 7.4 (a marker of infection), the wall material structure undergoes a reversible change - expansion, which in turn compresses the microcapsule to accelerate drug release.

[0032] Step 4, Post-processing: The printed green body is sintered at high temperature to obtain a dense zirconia ceramic periodontal splint. The microcapsules are dispersed in a solvent and impregnated under vacuum to allow the microcapsule solution to penetrate into the microcavities. The solvent is then removed by drying to allow the microcapsules to be placed in the microcavities. On the inner surface of the splint that is bonded to the teeth, a grid-like microporous structure is formed by controlling the printing path, with the pore size being 1-5 μm and the depth being 5-10 μm.

[0033] The flexural strength of the zirconia ceramic is not less than 800 MPa. The solvent can be an ethanol-water mixture (ethanol content 30%~50%), which can balance the dissolution of cyclodextrin and the dispersion of polyurethane coating, with moderate volatility, high safety and easy process control.

[0034] This invention is not limited to the preferred embodiments described above. Anyone can derive other products in various forms under the guidance of this invention. However, regardless of any changes in shape or structure, any technical solution that is the same as or similar to this application falls within the protection scope of this invention.

Claims

1. A method for preparing a zirconia ceramic periodontal splint, characterized in that, Includes the following steps: Step 1: Prepare a ceramic slurry containing zirconium oxide powder and ether-based organic solvent; Step 2: Based on the patient's intraoral scan data, design a three-dimensional digital model of a periodontal splint that fits the lingual morphology of the patient's teeth. Step 3: Place the ceramic slurry into the inkjet 3D printing equipment, spray the ceramic slurry and support material simultaneously, and print the periodontal splint green layer by layer. During the layer-by-layer printing process, several microcavities are generated inside the periodontal splint. Step 4: The green embryo is sintered at high temperature to obtain the finished zirconia ceramic periodontal splint. The microcapsules are dispersed in a solvent and impregnated under vacuum to allow the microcapsule solution to penetrate into the microcavity. Then, the solvent is removed by drying to allow the microcapsules to be placed in the microcavity.

2. The method for preparing the zirconia ceramic periodontal splint according to claim 1, characterized in that: The inner wall of the microcavity has a porous structure, and the inside of the microcavity is connected to the outside of the periodontal splint through the porous structure, so that the microcapsule can release antibacterial components outward through the porous structure.

3. The method for preparing the zirconia ceramic periodontal splint according to claim 2, characterized in that: The pore structure is distributed in a gradient from the inside to the outside. The porosity of the part of the pore structure near the inside of the microcavity is 30%-50%, and the porosity of the part of the pore structure near the outside of the periodontal splint is less than 10%.

4. The method for preparing the zirconia ceramic periodontal splint according to claim 1, characterized in that: In step three, when the inkjet 3D printing equipment prints layer by layer to 50%-80% of the total volume of the microcavity, the microcavity is kept open, and the microcapsule is placed into the microcavity through the opening.

5. The method for preparing the zirconia ceramic periodontal splint according to claim 1, characterized in that: The periodontal splint has a grid-like microporous structure on the surface where it is bonded to the teeth. The pore size of the microporous structure is 1-5 μm and the depth of the microporous structure is 5-10 μm.

6. The method for preparing the zirconia ceramic periodontal splint according to claim 1, characterized in that: The microcavities are spherical structures with a diameter of 50-200 μm, and several microcavities are distributed in a honeycomb pattern. The printing layer thickness of the green embryo is 20-80 μm.

7. The method for preparing the zirconia ceramic periodontal splint according to claim 1, characterized in that: The microcapsules are prepared by molecular encapsulation, the core material of the microcapsules is an antibacterial agent, and the wall material of the microcapsules is cyclodextrin.

8. The method for preparing the zirconia ceramic periodontal splint according to claim 7, characterized in that: The wall material of the microcapsule contains a pH-sensitive material, which accelerates the release of the microcapsule when the pH of the periodontal pocket is greater than 7.

4.

9. The method for preparing the zirconia ceramic periodontal splint according to claim 1, characterized in that: The outer surface of the microcapsule is coated with a polyurethane methacrylate-based coating.

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