3D printing silicon nitride gradient structure ceramic implant and preparation method thereof

Abstract

The invention discloses a 3D printed silicon nitride gradient structure ceramic implant and a preparation method thereof. The 3D printed silicon nitride gradient structure ceramic implant comprises an abutment, a root part and a connecting body part for connecting the abutment and the root part, the root part comprises a root part external thread and a root part biological combination body, and the root part external thread is arranged on the outer surface of the root part biological combination body in a sleeving manner; the connector part comprises a connector external thread and a connector body, and the connector external thread is arranged on the outer surface of the connector body in a sleeving mode; the abutment comprises an abutment external thread and an abutment body, and the abutment external thread is arranged on the outer surface of the abutment body in a sleeving manner; the root biological combination body is of a three-dimensional hollow structure; the root biological combination body is connected with the abutment body; the silicon nitride gradient structure ceramic implant is integrally formed, the overall structure stability is high, meanwhile, the root provides a space for growth of connective tissue, and the growth activity of the connective tissue is high.

Description

Technical Field

[0001] The present invention relates to the field of implants, and in particular to the field of a 3D printed silicon nitride gradient structure ceramic implant and a preparation method thereof. Background Art

[0002] Dental implants can solve the problem of missing teeth in patients. Silicon nitride bioceramics have better antibacterial, osteogenic, biocompatibility and other advantages, and have become the development direction of bioceramic dental implants.

[0003] However, after being fixed, existing implants often have poor bone-grasping properties, which reduces their stability and makes them prone to loosening. Furthermore, the implants have a weak ability to bind to the surrounding connective tissue inside the mouth, which can easily lead to bacterial adhesion and hinder the patient's subsequent recovery.

[0004] Therefore, how to achieve high physical connection strength between the implant and the crown and gum, high stability of the implant, and resistance to loosening, while achieving strong bonding ability and high biological activity between the implant root and the surrounding connective tissue inside the oral cavity has become a difficult problem that needs to be solved urgently in this field. Summary of the Invention

[0005] The purpose of the present invention is to provide a 3D printed silicon nitride gradient structure ceramic implant, which realizes the one-piece molding of the silicon nitride gradient structure ceramic implant, has strong overall structural stability, and at the same time, through the high density of the base, root and connecting body threads, improves the physical connection strength of the implant with the crown and the gum. At the same time, the root biocombination arranged inside the connecting body threads has a three-dimensional hollow structure and the porosity of the solid part is high, which provides space for the growth of connective tissue and realizes high activity of connective tissue growth.

[0006] In one aspect of the present invention, a 3D printed silicon nitride gradient structure ceramic implant is provided, comprising an abutment, a root, and a connector connecting the abutment and the root;

[0007] The root comprises a root external thread and a root biocombination body, wherein the root external thread is sleeved on the outer surface of the root biocombination body;

[0008] The connector portion includes a connector outer thread and a connector body, wherein the connector outer thread is sleeved on the outer surface of the connector body;

[0009] The abutment includes an abutment external thread and an abutment body, wherein the abutment external thread is sleeved on the outer surface of the abutment body;

[0010] The root biocombination is a three-dimensional hollow structure; the root biocombination is connected to the base body;

[0011] The root external thread is connected to the external thread of the connector; the root external thread and the external thread of the connector have the same pitch;

[0012] A first connecting hole is provided inside the base body;

[0013] The 3D printed silicon nitride gradient structure ceramic implant is formed in one piece.

[0014] The present invention has the following advantages over the prior art: the implant is connected to the crown through the base; the base is connected to the root through the connecting body, and the connection strength is high, while the connection with the gum is conducive to high connection strength with the gum; the implant is connected to the gum through the root, and the connection strength with the gum and biological tissues such as connective tissue is high, which is conducive to the survival of biological tissues;

[0015] By integrally forming the 3D printed silicon nitride gradient structure ceramic implant, the overall structural stability of the implant is achieved, and problems such as breakage or damage will not occur;

[0016] By sleeved on the outer surface of the root biocombination, the root external thread is provided with a high density and a high bonding strength with the gums, and the internal root biocombination is protected from damage, while biological tissues such as connective tissue can be in contact with the root biocombination; the root biocombination is a three-dimensional hollow structure, which provides sufficient space for biological tissue to grow in the root, thereby achieving a high bonding strength between the root and the biological tissue;

[0017] The first connection hole is provided inside the base body, which is conducive to connection with the crown and subsequent integrated processing.

[0018] Furthermore, a second connection hole communicating with the first connection hole is provided inside the connector body;

[0019] The outer surface of the root bioconjugate is provided with a first groove combined with the root external thread, and the first groove is thread-shaped and distributed on the outer surface of the root bioconjugate;

[0020] and / or

[0021] The root biocombination body is provided with a second connecting hole in the interior of one end close to the connector body;

[0022] and / or

[0023] A second groove is provided on the outside of one end of the root biocombination body close to the connector body, and a first protrusion matching the first groove is provided on the inside of the connector body.

[0024] The beneficial effect of the above step is that the first groove that is combined with the root external thread is provided on the outer surface of the root biocombination body, so that the root biocombination body and the root external thread are combined with high strength;

[0025] The root biocombination body is provided with a second connection hole in communication with the connector body at one end thereof, which is conducive to the formation of a silicon nitride gradient structure ceramic implant blank. During the processing, the biocombination blank can be fixed while the connector body and the connecting base blank are sequentially prepared on the root biocombination blank to obtain a silicon nitride gradient structure ceramic implant blank.

[0026] A second groove is provided on the outside of one end of the root biocombination body close to the connector body, and a first protrusion matching the first groove is provided inside the connector body, thereby achieving high bonding strength between the biocombination body and the connector body.

[0027] Furthermore, the diameter of the three-dimensional hollow holes of the root biocombination is 0.15-0.3 mm; the porosity of the solid part of the root biocombination is 30-40%;

[0028] The porosity of the base, the connecting body, and the root external thread is 4-10%;

[0029] and / or

[0030] The root length is 3-5 mm, and the root external thread width is 0.9-1.1 mm;

[0031] The thread pitch of the root external thread is 0.74-1.3mm;

[0032] Preferably, the first connecting hole inside the base is a hexagonal structure, the cross-section of the root external thread and the connecting external thread is hexagonal, the helix angle of the root external thread and the connecting external thread is 30°-45°, and the thread pitch of the connecting external thread is 1.0-1.5mm.

[0033] The beneficial effect of the above step is that the diameter of the three-dimensional hollow hole of the root biocombination is 0.15-0.3 mm, which is conducive to the production of biological tissue in the three-dimensional hollow hole and at the same time helps to improve the strength of the root biocombination;

[0034] The porosity of the solid part of the root biocombination is 30-40%. The high porosity is conducive to achieving high survival of biological tissues such as connective tissue in the root biocombination, thereby improving biological activity. The porosity of the base, the connector, and the root external thread is 4-10%, which achieves high strength of the base, the connector, and the root external thread, thereby avoiding problems such as damage during use.

[0035] The root external thread width is 0.9-1.1 mm, which is beneficial to improving the bonding strength between the root external thread and the biological combination, and is also beneficial to achieving high bonding strength between the root external thread and the gum structure;

[0036] The thread pitch of the root external thread is 0.74-1.3 mm, which is conducive to the entry of biological tissues such as connective tissue into the root biological combination through the space between the thread pitches.

[0037] One aspect of the present invention provides a method for preparing a 3D-printed silicon nitride gradient structure ceramic implant, characterized in that it comprises the following steps:

[0038] preparing a first slurry and preparing a second slurry;

[0039] Synchronously preparing a silicon nitride gradient structure ceramic implant blank using the first slurry and the second slurry by 3D printing; or first preparing a root biocombination blank by 3D printing using the first slurry;

[0040] Then, a root external thread blank is prepared on the surface of the root biocombination blank by 3D printing using the second slurry, and then a connecting body blank and a connecting base blank are successively prepared on the root biocombination blank to obtain a silicon nitride gradient structure ceramic implant blank;

[0041] cleaning the silicon nitride gradient structure ceramic implant body;

[0042] The cleaned silicon nitride gradient structure ceramic implant body is degummed and dried, and then the degummed and dried silicon nitride gradient structure ceramic implant body is sintered to obtain the 3D printed silicon nitride gradient structure ceramic implant body.

[0043] The beneficial effect of the present invention over the prior art is that, by preparing a root external thread blank on the surface of the root biocombination blank, and then successively preparing a connecting body blank and a connecting base blank on the root biocombination blank, a 3D printed silicon nitride gradient structure ceramic implant is formed in one piece;

[0044] The root biocombination body is prepared by 3D printing using the first slurry, so that the root biocombination body has a three-dimensional hollow structure;

[0045] By preparing the first slurry and the second slurry, the porosity of the solid part of the root biocombination body is high, and the porosity of the connecting body blank, the connecting base blank, and the root external thread blank is low.

[0046] By cleaning the silicon nitride gradient structure ceramic implant blank, the porosity of each part of the 3D printed silicon nitride gradient structure ceramic implant is not increased, and the surface strength of the silicon nitride gradient structure ceramic implant is improved by the high molecular polymer in the cleaning liquid. At the same time, it is beneficial to the partial exudation of excess small molecular organic matter in the silicon nitride gradient structure ceramic implant, which is beneficial to the subsequent debonding of the silicon nitride gradient structure ceramic implant;

[0047] Preferably, when preparing the root biocombination blank by 3D printing, the three-dimensional hollow structure is a minimal surface Fischer-Kochs, the equation is US=cos(2x)sin(y)cos(z)+cos(2y)sin(z)cos(x)+cos(2z)sin(x)cos(y)-t, f(x,y,z)=t; the aperture of the three-dimensional hollow structure is 0.15mm-0.35mm, and the wall thickness is 0.15mm-0.45mm;

[0048] Further preferably, when preparing the root biocombination body by 3D printing, the root biocombination body is printed on the outer surface of the connecting rod, and after printing is completed, the root biocombination body is fixed to one end outside the connecting rod;

[0049] The connecting rod includes a supporting portion and a connecting portion. The supporting portion is made of paraffin wax. After printing is completed, the root biocombination blank is fixed to the supporting portion.

[0050] A root external thread blank is prepared on the surface of the root biocombination blank by 3D printing using the second slurry, and then a connector blank and a connecting base blank are sequentially prepared on the root biocombination blank. The specific steps include printing the first groove portion of the connector blank on the second groove portion of the root biocombination blank, and then sequentially printing the remaining portion of the connector blank and the connecting base blank along the connecting portion of the connecting rod to obtain a silicon nitride gradient structure ceramic implant blank;

[0051] After the silicon nitride gradient structure ceramic implant body is debonded and dried, the supporting portion of the connecting rod is volatilized; after the connecting portion of the connecting rod is removed, the silicon nitride gradient structure ceramic implant body is sintered.

[0052] Furthermore, the preparation process of the first slurry includes the following steps:

[0053] First, polyborosilazane, β-phase silicon nitride ceramic powder, a first photocurable monomer, a crosslinker, a photoinitiator, and polystyrene microspheres are mixed in a mass ratio of (20-35): (20-35): (23-33): (4-6): (0.5-2): (3-5); then stirred for 15-20 seconds at a rotation speed of 2000-2500 rpm to prepare a first slurry.

[0054] The beneficial effect of the above step is that, by using polyborosilazane, the polyborosilazane is converted into boron nitride during the sintering process after sintering, thereby increasing the boron nitride content and improving the strength of the prepared green body, thereby reducing the content of the first photocurable monomer, thereby reducing the content of the polymer compound of the monomer polymerization in the green body, thereby reducing the difficulty of debinding the cross-linked polymer compound;

[0055] At the same time, because the β-phase silicon nitride ceramic powder is a high-temperature stable phase, no crystal phase transition and shrinkage occur during the sintering process, which solves the problem of large sintering shrinkage in the traditional mixing method and is conducive to reducing the shrinkage rate by 10-15%.

[0056] The polystyrene microspheres are helpful to improve the porosity of the entity part of the root biocombination.

[0057] Furthermore, the preparation process of the first slurry includes the following steps:

[0058] preparing ceramic particles;

[0059] Then, ceramic particles, a second photocurable monomer, a crosslinker, and a photoinitiator are mixed in a mass ratio of (40-70): (25-40): (4-6): (0.5-2); and then stirred for 15-20 seconds at a speed of 2000-2500 rpm to prepare a first slurry; the solvent is water;

[0060] The preparation process of ceramic particles includes the following steps:

[0061] Mixing polyborosilazane, β-phase silicon nitride ceramic powder, solvent, first binder, and polystyrene microspheres in a mass ratio of (20-35):(20-35):(35-60):(3-10):(3-5) to obtain a granulation slurry;

[0062] Granulating the granulation slurry at a temperature of 60-80° C. to obtain a ceramic particle body, and then heating the ceramic particle body to obtain the ceramic particles;

[0063] The first binder includes polymerizable monomers including one or more of polyethylene glycol diacrylate and dipropylene glycol diacrylate.

[0064] The beneficial effect of adopting the previous step is that ceramic particles are first prepared by polyborosilazane, β-phase silicon nitride ceramic powder, and polystyrene microspheres, and then a first slurry is prepared by the ceramic particles, and then a root bioconjugate body is prepared by the first slurry, that is, the porosity of the root bioconjugate body is achieved, and the problem of reduced strength of the root bioconjugate body at the same porosity is avoided. At the same time, it is beneficial to avoid the deformation or damage of the root bioconjugate body caused by the volatilization of polystyrene microspheres during debinding of the root bioconjugate body. At the same time, the content of volatile substances such as organic matter and solvents in the root bioconjugate body can be basically consistent with the content of volatile substances such as organic matter and solvents in the connector body, the connecting base body, and the root external thread body, which is beneficial to achieve basically consistent shrinkage when sintering together, and the shrinkage rate is low, and the sintering shrinkage rate of the root bioconjugate body during the sintering process is achieved to be 3-5%;

[0065] By including the first binder as a polymerizable monomer including one or more of polyethylene glycol diacrylate and dipropylene glycol diacrylate, the fluidity of the granulation slurry is low, and the bonding strength is high during granulation through the two functional groups, thereby improving the strength of the ceramic particles.

[0066] Furthermore, the ceramic particle body is heated from room temperature to 80-100°C at a heating rate of 9-10°C / min; from 80-100°C to 180-220°C at a heating rate of 8-9°C / min; and from 180-220°C to 300-320°C at a heating rate of 4-5°C / min.

[0067] The beneficial effect of the above step is that the ceramic particles have high strength and a large number of through-holes, and the polyborosilazane inside is not decomposed and the polymerized high molecular compound is not volatilized. However, the large number of through-holes in the ceramic particles is conducive to the smooth volatilization of the root biocombination body during sintering and avoids problems such as cracking.

[0068] That is, by heating from room temperature to 80-100°C at a heating rate of 9-10°C / min, a large amount of small molecules such as solvents are rapidly volatilized to form through-holes with smaller pore sizes; by heating from 80-100°C to 180-220°C at a heating rate of 8-9°C / min, the rapid heating avoids the problem of high fluidity of polystyrene microspheres in this temperature range; by heating from 180-220°C to 300-320°C at a heating rate of 4-5°C / min, the polystyrene microspheres are slowly volatilized on the basis of the originally generated through-holes with smaller pore sizes, forming through-holes with larger pore sizes, which is beneficial to the volatilization of high molecular organic matter in the subsequent sintering process.

[0069] Furthermore, the preparation process of the second slurry includes the following steps:

[0070] First, polyborosilazane, β-phase silicon nitride ceramic powder, a first photocurable monomer, a crosslinking agent, and a photoinitiator are mixed in a mass ratio of (20-35): (20-35): (25-40): (4-6): (0.5-2); then stirred for 15-20 seconds at a rotation speed of 2000-2500 rpm to prepare a second slurry;

[0071] and / or

[0072] The process of cleaning the silicon nitride gradient structure ceramic implant body comprises the following steps:

[0073] The cleaning solution is prepared by mixing polyacrylic acid and propylene carbonate in a mass ratio of (25-35): (65-75) to obtain the cleaning solution;

[0074] Soak the silicon nitride gradient structure ceramic implant body in the cleaning solution for 30-60 minutes.

[0075] The beneficial effect of the above step is that, by using polyborosilazane, the polyborosilazane is converted into silicon boron nitrogen ceramics during the sintering process after sintering, thereby increasing the ceramic content and improving the strength of the prepared green body, thereby reducing the content of the first photocurable monomer, thereby reducing the content of the polymer compound of the monomer polymerization in the green body, thereby reducing the difficulty of debinding the cross-linked polymer compound;

[0076] At the same time, because the β-phase silicon nitride ceramic powder is a high-temperature stable phase, no crystal phase transition and shrinkage occur during the sintering process, which solves the problem of large sintering shrinkage in the traditional mixing method and is conducive to reducing the shrinkage rate by 10-15%.

[0077] By using cleaning liquids such as polyacrylic acid and propylene carbonate, the porosity of each part of the 3D printed silicon nitride gradient structure ceramic implant is not increased. The surface strength of the silicon nitride gradient structure ceramic implant is improved by the high molecular polymer in the cleaning liquid. At the same time, it is beneficial to the partial exudation of excess small molecular organic matter in the silicon nitride gradient structure ceramic implant, which is beneficial to the subsequent debonding of the silicon nitride gradient structure ceramic implant.

[0078] Furthermore, the cross-linking agent is di(trimethylolpropane)tetraacrylate;

[0079] The first photocurable monomer comprises a photocurable monomer A and a photocurable monomer B in a mass ratio of (15-18): (12-13);

[0080] The second photocurable monomer comprises a photocurable monomer A and a photocurable monomer B in a mass ratio of (20-25): (8-10);

[0081] The photocurable monomer A includes one of 1,4-butanediol diacrylate, dipropylene glycol diacrylate, and neopentyl glycol diacrylate;

[0082] The photocurable monomer B includes ethoxyethoxyethoxyacrylate or mono(2-acryloyloxyethyl)succinate.

[0083] The beneficial effect of the above step is that the photocurable monomer A includes one of 1,4-butanediol diacrylate, dipropylene glycol diacrylate, and neopentyl glycol diacrylate, so that the photocurable monomer A has strong bonding strength during polymerization, low viscosity, and good dispersibility, and the polymer compound after polymerization has a large molecular weight and requires slow debonding.

[0084] The photocurable monomer B includes ethoxyethoxyethoxyacrylate or mono(2-acryloyloxyethyl)succinate, which has good dispersibility and low viscosity, which is conducive to improving the precision during 3D printing. The molecular weight of the polymer organic matter after polymerization is small and easy to discharge glue, but the viscosity is relatively reduced during polymerization;

[0085] The first photocurable monomer includes a photocurable monomer A and a photocurable monomer B in a mass ratio of (15-18): (12-13). The content of the photocurable monomer A is relatively low, but there are no large particles in the second slurry. Therefore, the strength of the blank obtained after the second slurry is photocured is not affected, and it is beneficial to the debinding of the root external thread blank, the connector blank, and the connection base blank.

[0086] The second photocurable monomer includes a photocurable monomer A and a photocurable monomer B in a mass ratio of (20-25): (8-10). The photocurable monomer A is relatively high and has a high viscosity during polymerization, which is beneficial to the bonding strength between ceramic particles during photocuring and is beneficial to molding. Since the pores between the particles are larger than the pores between the powders, it is beneficial to the debinding of larger polymer compounds.

[0087] Furthermore, the specific process of degumming and drying includes the following steps: drying the cleaned silicon nitride gradient structure ceramic implant body by microwave drying, heating from room temperature to 90-100°C at a heating rate of 9-10°C / min; heating from 90-100°C to 280-320°C at a heating rate of 6-7°C / min, and keeping at 280-320°C for 0.5-1h; heating from 280-320°C to 400-410°C at a heating rate of 5-6°C / min;

[0088] The specific process of sintering includes the following steps:

[0089] The debonded and dried silicon nitride gradient structure ceramic implant body is heated to 400-450°C at a heating rate of 5-6°C / min;

[0090] In a nitrogen atmosphere, the temperature was raised from 400-450°C to 550-650°C at a nitrogen pressure of 1-3 MPa at a heating rate of 4-5°C / min; the temperature was raised from 550-650°C to 900-1750°C at a nitrogen pressure of 4-8 MPa, and the holding time at 900-1750°C was 1-2 h;

[0091] The sintering shrinkage rate of the silicon nitride gradient structure ceramic implant body during sintering is 3-5%.

[0092] The beneficial effect of the above step is that the problem of low internal temperature and incomplete debinding during debinding is avoided by microwave drying the silicon nitride gradient structure ceramic implant blank.

[0093] By heating the temperature from room temperature to 90-100°C at a heating rate of 9-10°C / min, small molecular weight volatiles in the green body are rapidly volatilized to form channels with small pore diameters; by heating the temperature from 90-100°C to 280-320°C at a heating rate of 6-7°C / min, volatiles with slightly larger molecular weights are slowly volatilized on the basis of the small channels, thereby further increasing the pore diameters of the channels; and by heating the temperature from 280-320°C to 400-410°C at a heating rate of 5-6°C / min, organic matter with larger molecular weights is slowly decomposed and volatilized after monomer polymerization.

[0094] The debonded and dried silicon nitride gradient structure ceramic implant body is heated to 400-410°C at a heating rate of 5-6°C / min to achieve rapid heating, which is conducive to the volatilization of a small amount of residue.

[0095] By heating from 400-410°C to 550-650°C in a nitrogen atmosphere at a nitrogen pressure of 1-3 MPa at a heating rate of 4-5°C / min, it is beneficial to decompose the polyborosilazane and avoid oxidation of the boron element. At the same time, this nitrogen pressure is conducive to the slow volatilization of the decomposed organic matter. By heating from 550-650°C to 900-1750°C at a nitrogen pressure of 4-8 MPa and holding at 900-1750°C for 1-2 hours, it is beneficial to ceramicize the polyborosilazane and avoid oxidation.

[0096] The sintering shrinkage rate of the silicon nitride gradient structure ceramic implant body during the sintering process is 3-5%, which is beneficial to avoid cracking or damage during the sintering process. BRIEF DESCRIPTION OF THE DRAWINGS

[0097] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings required for use in the embodiments of the present invention will be described below.

[0098] Figure 1 This is a structural diagram of the 3D printed silicon nitride gradient structure ceramic implant of the present invention.

[0099] Markings shown in the accompanying drawings: 1. base; 2. connector; 3. root; 4. connector external thread; 5. connector body; 6. root biocombination; 7. root external thread. DETAILED DESCRIPTION

[0100] In order to better understand the technical solution of the present invention, the present invention is further described below in conjunction with specific embodiments.

[0101] Example 1:

[0102] In one aspect of the present embodiment, a 3D printed silicon nitride gradient structure ceramic implant is provided, comprising an abutment 1, a root 3, and a connecting body 2 connecting the abutment 1 and the root 3;

[0103] The root portion 3 includes a root external thread 7 and a root biocombination body 6. The root external thread 7 is sleeved on the outer surface of the root biocombination body 6. The outer surface of the root biocombination body 6 is provided with a first groove combined with the root external thread 7. The first groove is thread-shaped and distributed on the outer surface of the root biocombination body 6.

[0104] The connector portion 2 includes a connector outer thread 4 and a connector body 5, wherein the connector outer thread 4 is sleeved on the outer surface of the connector body 5;

[0105] The abutment 1 comprises an abutment external thread and an abutment body, wherein the abutment external thread is sleeved on the outer surface of the abutment body;

[0106] The root biological combination body 6 is a three-dimensional hollow structure; the root biological combination body 6 is connected to the base body;

[0107] The root external thread 7 is connected to the connecting external thread 4; the root external thread 7 and the connecting external thread 4 have the same pitch;

[0108] A first connecting hole is provided inside the base body; a second connecting hole is provided inside the connector body 5 and is connected to the first connecting hole; the first connecting hole inside the base body is a hexagonal structure, and the cross-section of the root external thread 7 and the connector external thread 4 is hexagonal; the helix angle between the root external thread 7 and the connector external thread 4 is 38°, and the thread pitch of the connector external thread 4 is 1.2mm;

[0109] The diameter of the three-dimensional hollow hole of the root biocombination 6 is 0.22 mm; the porosity of the solid part of the root biocombination 6 is 32%;

[0110] The porosity of the base 1, the connecting body 2, and the root external thread 7 is 7%;

[0111] The 3D printed silicon nitride gradient structure ceramic implant is formed in one piece.

[0112] Another aspect of this embodiment provides a method for preparing a 3D-printed silicon nitride gradient structure ceramic implant, comprising the following steps:

[0113] A first slurry is prepared, wherein the preparation process of the first slurry comprises the following steps:

[0114] First, polyborosilazane, β-phase silicon nitride ceramic powder, a first photocurable monomer, a crosslinking agent, a photoinitiator, and polystyrene microspheres are mixed in a mass ratio of 28:28:28:5:1.3:4; then stirred for 18 seconds at a rotation speed of 2300 rpm to prepare a first slurry.

[0115] A second slurry is prepared, wherein the preparation process of the second slurry comprises the following steps:

[0116] First, polyborosilazane, β-phase silicon nitride ceramic powder, a first photocurable monomer, a crosslinking agent, and a photoinitiator were mixed in a mass ratio of 28:28:32:5.5:1.5; then stirred for 18 seconds at a speed of 2300 rpm to prepare a second slurry;

[0117] The cross-linking agent is di(trimethylolpropane)tetraacrylate;

[0118] The first photocurable monomer includes a photocurable monomer A and a photocurable monomer B in a mass ratio of 16.5:12.5;

[0119] The photocurable monomer A includes 1,4-butanediol diacrylate;

[0120] The photocurable monomer B includes mono(2-acryloyloxyethyl)succinate.

[0121] Synchronously preparing a silicon nitride gradient structure ceramic implant blank using the first slurry and the second slurry by 3D printing; or first preparing a root biocombination blank by 3D printing using the first slurry;

[0122] The specific process is as follows: the first slurry is prepared by double-disc 3D printing, and the root biocombination blank is printed using disk A; when the root biocombination blank is prepared by 3D printing, the three-dimensional hollow structure is a minimal surface Fischer-Kochs, and the equation is US = cos(2x)sin(y)cos(z)+cos(2y)sin(z)cos(x)+cos(2z)sin(x)cos(y)-t, f(x,y,z)=t; the three-dimensional hollow structure has an aperture of 0.25mm and a wall thickness of 0.3mm;

[0123] The second slurry is prepared by double-disc 3D printing, and the B-disc is used to print the surface of the root biocombination blank to prepare the root external thread blank, the connecting body blank, and the connecting base blank to obtain a silicon nitride gradient structure ceramic implant blank;

[0124] The silicon nitride gradient structure ceramic implant body is cleaned; the process of cleaning the silicon nitride gradient structure ceramic implant body comprises the following steps:

[0125] The cleaning solution is prepared by mixing polyacrylic acid and propylene carbonate in a mass ratio of 30:70 to obtain the cleaning solution;

[0126] The silicon nitride gradient structure ceramic implant body was soaked in the cleaning solution for 45 minutes.

[0127] The cleaned silicon nitride gradient structure ceramic implant body is degummed and dried. The specific process of degumming and drying includes the following steps: the cleaned silicon nitride gradient structure ceramic implant body is dried by microwave, heating from room temperature to 95°C at a heating rate of 9.5°C / min; heating from 95°C to 300°C at a heating rate of 6.5°C / min, and keeping at 300°C for 0.75h; heating from 300°C to 405°C at a heating rate of 5.5°C / min;

[0128] The degummed and dried silicon nitride gradient structure ceramic implant body is then sintered to obtain the 3D printed silicon nitride gradient structure ceramic implant. The specific sintering process includes the following steps:

[0129] The debonded and dried silicon nitride gradient structure ceramic implant body was heated to 405°C at a heating rate of 5.5°C / min;

[0130] In nitrogen atmosphere, the temperature was increased from 405°C to 600°C at a nitrogen pressure of 2 MPa at a heating rate of 4.5°C / min; the temperature was increased from 600°C to 1325°C at a nitrogen pressure of 6 MPa, and the holding time at 1325°C was 1.5 h;

[0131] The sintering shrinkage of the silicon nitride gradient structure ceramic implant body is 4% during the sintering process.

[0132] Example 2:

[0133] The same contents as those in Example 1 are not described in detail here. The differences between this embodiment and Example 1 are as follows:

[0134] One aspect of this embodiment provides a 3D printed silicon nitride gradient structure ceramic implant, wherein the root biocombination body 6 is provided with a second connection hole in communication with one end of the connector body 5 close to the root biocombination body 6;

[0135] A second groove is provided on the outside of one end of the root biocombination 6 close to the connector body 5 , and a first protrusion matching the first groove is provided on the inside of the connector body 5 .

[0136] The length of the root 3 is 4 mm, and the width of the root external thread 7 is 1 mm;

[0137] The helix angle between the root external thread 7 and the connecting external thread 4 is 32°, the thread pitch of the connecting external thread 4 is 1.4 mm, and the thread pitch of the root external thread 7 is 1.4 mm;

[0138] The diameter of the three-dimensional hollow hole of the root biocombination 6 is 0.18 mm; the porosity of the solid part of the root biocombination 6 is 35%;

[0139] The porosity of the base 1, the connecting body 2, and the root external thread 7 is 5%.

[0140] Another aspect of this embodiment provides a method for preparing a 3D-printed silicon nitride gradient structure ceramic implant, comprising the following steps:

[0141] The preparation process of the first slurry comprises the following steps:

[0142] preparing ceramic particles;

[0143] Then, ceramic particles, a second photocurable monomer, a crosslinking agent, and a photoinitiator were mixed in a mass ratio of 66:33:5:1.3; and then stirred for 19 seconds at a speed of 2400 rpm to prepare a first slurry; the solvent was water;

[0144] The preparation process of ceramic particles includes the following steps:

[0145] Mixing polyborosilazane, β-phase silicon nitride ceramic powder, solvent, first binder, and polystyrene microspheres in a mass ratio of 33:33:58:8:4.5 to obtain a granulation slurry;

[0146] granulating the granulation slurry at 70° C. to obtain a ceramic particle body, and then heating the ceramic particle body to obtain the ceramic particles;

[0147] The first binder includes a polymerizable monomer including polyethylene glycol diacrylate.

[0148] The ceramic particle body was heated from room temperature to 90°C at a heating rate of 9.5°C / min; from 90°C to 200°C at a heating rate of 8.5°C / min; and from 200°C to 310°C at a heating rate of 4.5°C / min.

[0149] The second photocurable monomer comprises a photocurable monomer A and a photocurable monomer B in a mass ratio of 23:9;

[0150] The preparation process of the second slurry comprises the following steps:

[0151] First, polyborosilazane, β-phase silicon nitride ceramic powder, a first photocurable monomer, a crosslinking agent, and a photoinitiator were mixed in a mass ratio of 33:33:31:5.3:1.3; and then stirred for 19 minutes at a speed of 2400 rpm to prepare a second slurry;

[0152] The photocurable monomer A includes dipropylene glycol diacrylate;

[0153] The photocurable monomer B includes ethoxyethoxyethoxyacrylate.

[0154] When preparing the root biocombination body by 3D printing, the root biocombination body is printed on the outer surface of the connecting rod, and after printing is completed, the root biocombination body is fixed to one end outside the connecting rod;

[0155] The connecting rod includes a supporting portion and a connecting portion. The supporting portion is made of paraffin wax. After printing is completed, the root biocombination blank is fixed to the supporting portion.

[0156] A root external thread blank is prepared on the surface of the root biocombination blank by 3D printing using the second slurry, and then a connector blank and a connecting base blank are sequentially prepared on the root biocombination blank. The specific steps include printing the first groove portion of the connector blank on the second groove portion of the root biocombination blank, and then sequentially printing the remaining portion of the connector blank and the connecting base blank along the connecting portion of the connecting rod to obtain a silicon nitride gradient structure ceramic implant blank;

[0157] After the silicon nitride gradient structure ceramic implant body is debonded and dried, the supporting portion of the connecting rod is volatilized; after the connecting portion of the connecting rod is removed, the silicon nitride gradient structure ceramic implant body is sintered.

[0158] A cleaning solution is prepared by mixing polyacrylic acid and propylene carbonate in a mass ratio of 28:72 to obtain a cleaning solution;

[0159] The silicon nitride gradient structure ceramic implant body was soaked in the cleaning solution for 55 minutes.

[0160] The specific process of degumming and drying includes the following steps: drying the cleaned silicon nitride gradient structure ceramic implant blank by microwave drying, heating from room temperature to 98°C at a heating rate of 9.2°C / min; heating from 98°C to 310°C at a heating rate of 6.8°C / min, and keeping at 310°C for 0.6h; heating from 310°C to 408°C at a heating rate of 5.8°C / min;

[0161] The specific process of sintering includes the following steps:

[0162] The debonded and dried silicon nitride gradient structure ceramic implant body was heated to 408°C at a heating rate of 5.86°C / min.

[0163] In nitrogen atmosphere, the temperature was increased from 408°C to 630°C at a nitrogen pressure of 1.5 MPa at a heating rate of 4.8°C / min; the temperature was increased from 630°C to 1730°C at a nitrogen pressure of 7 MPa, and the holding time at 1730°C was 1.2 h;

[0164] The sintering shrinkage of the silicon nitride gradient structure ceramic implant body is 3.6% during the sintering process.

[0165] Example 3:

[0166] The same contents as those in Example 1 are not described in detail here. The differences between this embodiment and Example 1 are as follows:

[0167] One aspect of this embodiment provides a 3D printed silicon nitride gradient structure ceramic implant, wherein the root biocombination body 6 is provided with a second connection hole in communication with one end of the connector body 5 close to the root biocombination body 6;

[0168] A second groove is provided on the outside of one end of the root biocombination 6 close to the connector body 5 , and a first protrusion matching the first groove is provided on the inside of the connector body 5 .

[0169] The length of the root 3 is 3.5 mm, and the width of the root external thread 7 is 1.05 mm;

[0170] The helix angle between the root external thread 7 and the connecting external thread 4 is 40°, the thread pitch of the connecting external thread 4 is 1.1 mm, and the thread pitch of the root external thread 7 is 0.9 mm;

[0171] The diameter of the three-dimensional hollow hole of the root biocombination 6 is 0.28 mm; the porosity of the solid part of the root biocombination 6 is 38%;

[0172] The porosity of the base 1 , the connecting body 2 , and the root external thread 7 is 8%.

[0173] Another aspect of this embodiment provides a method for preparing a 3D-printed silicon nitride gradient structure ceramic implant, comprising the following steps:

[0174] The preparation process of the first slurry comprises the following steps:

[0175] preparing ceramic particles;

[0176] Then, ceramic particles, a second photocurable monomer, a crosslinking agent, and a photoinitiator were mixed in a mass ratio of 55:30:4.8:1; and then stirred for 16 seconds at a speed of 2100 rpm to prepare a first slurry; the solvent was water;

[0177] The preparation process of ceramic particles includes the following steps:

[0178] Mixing polyborosilazane, β-phase silicon nitride ceramic powder, solvent, first binder, and polystyrene microspheres in a mass ratio of 25:30:40:6:4 to obtain a granulation slurry;

[0179] granulating the granulation slurry at a temperature of 65° C. to obtain a ceramic particle body, and then heating the ceramic particle body to obtain the ceramic particles;

[0180] The first binder includes a polymerizable monomer including dipropylene glycol diacrylate.

[0181] The ceramic particle body was heated from room temperature to 95°C at a heating rate of 9.8°C / min; from 95°C to 210°C at a heating rate of 8.8°C / min; and from 210°C to 316°C at a heating rate of 4.8°C / min.

[0182] The second photocurable monomer comprises a photocurable monomer A and a photocurable monomer B in a mass ratio of 21:9.5;

[0183] The preparation process of the second slurry comprises the following steps:

[0184] First, polyborosilazane, β-phase silicon nitride ceramic powder, a first photocurable monomer, a crosslinking agent, and a photoinitiator were mixed in a mass ratio of 25:30:30:4.8:1; then stirred for 16 seconds at a speed of 2100 rpm to prepare a second slurry;

[0185] The photocurable monomer A includes neopentyl glycol diacrylate;

[0186] The photocurable monomer B includes ethoxyethoxyethoxyacrylate.

[0187] When preparing the root biocombination body by 3D printing, the root biocombination body is printed on the outer surface of the connecting rod, and after printing is completed, the root biocombination body is fixed to one end outside the connecting rod;

[0188] The connecting rod includes a supporting portion and a connecting portion. The supporting portion is made of paraffin wax. After printing is completed, the root biocombination blank is fixed to the supporting portion.

[0189] A root external thread blank is prepared on the surface of the root biocombination blank by 3D printing using the second slurry, and then a connector blank and a connecting base blank are sequentially prepared on the root biocombination blank. The specific steps include printing the first groove portion of the connector blank on the second groove portion of the root biocombination blank, and then sequentially printing the remaining portion of the connector blank and the connecting base blank along the connecting portion of the connecting rod to obtain a silicon nitride gradient structure ceramic implant blank;

[0190] After the silicon nitride gradient structure ceramic implant body is debonded and dried, the supporting portion of the connecting rod is volatilized; after the connecting portion of the connecting rod is removed, the silicon nitride gradient structure ceramic implant body is sintered.

[0191] A cleaning solution is prepared by mixing polyacrylic acid and propylene carbonate in a mass ratio of 33:67 to obtain a cleaning solution;

[0192] The silicon nitride gradient structure ceramic implant body was soaked in the cleaning solution for 40 minutes.

[0193] The specific process of degumming and drying includes the following steps: drying the cleaned silicon nitride gradient structure ceramic implant blank by microwave drying, heating from room temperature to 92°C at a heating rate of 9.2°C / min; heating from 92°C to 290°C at a heating rate of 6.2°C / min, and keeping at 290°C for 0.9h; heating from 290°C to 401°C at a heating rate of 5.2°C / min;

[0194] The specific process of sintering includes the following steps:

[0195] The debonded and dried silicon nitride gradient structure ceramic implant body was heated to 401°C at a heating rate of 5.2°C / min.

[0196] In a nitrogen atmosphere, the temperature was increased from 401°C to 580°C at a nitrogen pressure of 2.5 MPa at a heating rate of 4.3°C / min; the temperature was increased from 580°C to 1000°C at a nitrogen pressure of 5 MPa, and the holding time at 1000°C was 1.9 h;

[0197] The sintering shrinkage of the silicon nitride gradient structure ceramic implant body is 3.3% during the sintering process.

[0198] The above description is merely a preferred embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of the invention herein is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the inventive concept. For example, the above-mentioned features may have similar functions to (but not limited to) those disclosed in this application.

Claims

1. A 3D printed silicon nitride gradient structure ceramic implant, characterized in that: It includes a base, a root, and a connecting body connecting the base and the root; The root comprises a root external thread and a root biocombination body, wherein the root external thread is sleeved on the outer surface of the root biocombination body; The connector portion includes a connector outer thread and a connector body, wherein the connector outer thread is sleeved on the outer surface of the connector body; The abutment includes an abutment external thread and an abutment body, wherein the abutment external thread is sleeved on the outer surface of the abutment body; The root biocombination is a three-dimensional hollow structure; the root biocombination is connected to the base body; The root external thread is connected to the external thread of the connector; the root external thread and the external thread of the connector have the same pitch; A first connecting hole is provided inside the base body; The 3D printed silicon nitride gradient structure ceramic implant is formed in one piece.

2. The 3D printed silicon nitride gradient structure ceramic implant according to claim 1, characterized in that: A second connection hole communicating with the first connection hole is provided inside the connector body; The outer surface of the root bioconjugate is provided with a first groove combined with the root external thread, and the first groove is thread-shaped and distributed on the outer surface of the root bioconjugate; and / or The root biocombination body is provided with a second connection hole in the interior of one end close to the connector body; and / or A second groove is provided on the outside of one end of the root biocombination body close to the connector body, and a first protrusion matching the first groove is provided on the inside of the connector body.

3. The 3D printed silicon nitride gradient structure ceramic implant according to claim 1, characterized in that: The diameter of the three-dimensional hollow holes of the root biocombination is 0.15-0.3 mm; the porosity of the solid part of the root biocombination is 30-40%; The porosity of the base, the connecting body, and the root external thread is 4-10%; and / or The root length is 3-5 mm, and the root external thread width is 0.9-1.1 mm; The thread pitch of the root external thread is 0.74-1.3 mm.

4. A method for preparing a 3D printed silicon nitride gradient structure ceramic implant, characterized in that: The following steps are involved: preparing a first slurry and preparing a second slurry; Synchronously preparing a silicon nitride gradient structure ceramic implant blank using the first slurry and the second slurry by 3D printing; or first preparing a root biocombination blank by 3D printing using the first slurry; Then, a root external thread blank is prepared on the surface of the root biocombination blank by 3D printing using the second slurry, and then a connecting body blank and a connecting base blank are successively prepared on the root biocombination blank to obtain a silicon nitride gradient structure ceramic implant blank; cleaning the silicon nitride gradient structure ceramic implant body; The cleaned silicon nitride gradient structure ceramic implant body is degummed and dried, and then the degummed and dried silicon nitride gradient structure ceramic implant body is sintered to obtain the 3D printed silicon nitride gradient structure ceramic implant body.

5. The method for preparing a 3D printed silicon nitride gradient structure ceramic implant according to claim 4, characterized in that: The preparation process of the first slurry comprises the following steps: First, polyborosilazane, β-phase silicon nitride ceramic powder, a first photocurable monomer, a crosslinker, a photoinitiator, and polystyrene microspheres are mixed in a mass ratio of (20-35): (20-35): (23-33): (4-6): (0.5-2): (3-5); then stirred for 15-20 seconds at a rotation speed of 2000-2500 rpm to prepare a first slurry.

6. The method for preparing a 3D printed silicon nitride gradient structure ceramic implant according to claim 4, characterized in that: The preparation process of the first slurry comprises the following steps: preparing ceramic particles; Then, ceramic particles, a second photocurable monomer, a crosslinker, and a photoinitiator are mixed in a mass ratio of (40-70): (25-40): (4-6): (0.5-2); and then stirred for 15-20 seconds at a speed of 2000-2500 rpm to prepare a first slurry; the solvent is water; The preparation process of ceramic particles includes the following steps: Mixing polyborosilazane, β-phase silicon nitride ceramic powder, solvent, first binder, and polystyrene microspheres in a mass ratio of (20-35):(20-35):(35-60):(3-10):(3-5) to obtain a granulation slurry; Granulating the granulation slurry at a temperature of 60-80° C. to obtain a ceramic particle body, and then heating the ceramic particle body to obtain the ceramic particles; The first binder includes one or more of polyethylene glycol diacrylate and dipropylene glycol diacrylate.

7. The method for preparing a 3D printed silicon nitride gradient structure ceramic implant according to claim 6, characterized in that: The ceramic particle body is heated from room temperature to 80-100°C at a heating rate of 9-10°C / min; from 80-100°C to 180-220°C at a heating rate of 8-9°C / min; and from 180-220°C to 300-320°C at a heating rate of 4-5°C / min.

8. The method for preparing a 3D printed silicon nitride gradient structure ceramic implant according to claim 4, characterized in that: The preparation process of the second slurry comprises the following steps: First, polyborosilazane, β-phase silicon nitride ceramic powder, a first photocurable monomer, a crosslinking agent, and a photoinitiator are mixed in a mass ratio of (20-35): (20-35): (25-40): (4-6): (0.5-2); then stirred for 15-20 seconds at a rotation speed of 2000-2500 rpm to prepare a second slurry; and / or The process of cleaning the silicon nitride gradient structure ceramic implant body comprises the following steps: The cleaning solution is prepared by mixing polyacrylic acid and propylene carbonate in a mass ratio of (25-35): (65-75) to obtain the cleaning solution; Soak the silicon nitride gradient structure ceramic implant body in the cleaning solution for 30-60 minutes.

9. The method for preparing a 3D printed silicon nitride gradient structure ceramic implant according to any one of claims 5, 6, and 8, wherein: The cross-linking agent is di(trimethylolpropane)tetraacrylate; The first photocurable monomer comprises a photocurable monomer A and a photocurable monomer B in a mass ratio of (15-18): (12-13); The second photocurable monomer comprises a photocurable monomer A and a photocurable monomer B in a mass ratio of (20-25): (8-10); The photocurable monomer A includes one of 1,4-butanediol diacrylate, dipropylene glycol diacrylate, and neopentyl glycol diacrylate; The photocurable monomer B includes ethoxyethoxyethoxyacrylate or mono(2-acryloyloxyethyl)succinate.

10. The method for preparing a 3D printed silicon nitride gradient structure ceramic implant according to claim 4, characterized in that: The specific process of degumming and drying includes the following steps: drying the cleaned silicon nitride gradient structure ceramic implant blank by microwave drying, heating from room temperature to 90-100°C at a heating rate of 9-10°C / min; heating from 90-100°C to 280-320°C at a heating rate of 6-7°C / min, and keeping at 280-320°C for 0.5-1h; heating from 280-320°C to 400-410°C at a heating rate of 5-6°C / min; The specific process of sintering includes the following steps: The debonded and dried silicon nitride gradient structure ceramic implant body is heated to 400-410°C at a heating rate of 5-6°C / min; In a nitrogen atmosphere, the temperature was raised from 400-410°C to 550-650°C at a nitrogen pressure of 1-3 MPa at a heating rate of 4-5°C / min; the temperature was raised from 550-650°C to 900-1750°C at a nitrogen pressure of 4-8 MPa, and the holding time at 900-1750°C was 1-2 h; The sintering shrinkage rate of the silicon nitride gradient structure ceramic implant body during sintering is 3-5%.

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