3D printing method of SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implant

Abstract

The invention discloses a 3D printing method of a SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implant, relates to the technical field of 3D printing, and is used for preparing the temporomandibular joint implant with better corrosion resistance, wear resistance and biological stability. Comprising the following steps: S1, weighing powder; s2, mixing the materials; s3, stirring; the graded silicon nitride powder in the step S1 and the photosensitive resin in the step S2 are introduced into mechanical stirring equipment to be stirred for 2-3 h, and a mixture is obtained; s4, performing homogenizing; adding the mixture into a homogenizer to remove the organic solvent to obtain silicon nitride ceramic slurry; s5, scanning and modeling; s6, printing is carried out; placing the silicon nitride ceramic slurry in a 3D printer into which a temporomandibular joint implant model is introduced to obtain a temporomandibular joint implant printed piece; s7, sintering is conducted; s8, assembling is conducted; and the SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implant is obtained through mortise and tenon connection of the composite silicon nitride ceramic and a titanium alloy matrix. The temporomandibular joint implant with better corrosion resistance, wear resistance and biological stability can be prepared.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, specifically a 3D printing method for SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implants. Background Technology

[0002] The temporomandibular joint (TMJ), as the dynamic osseointegration between the mandible and the temporal bone at the base of the skull, plays an irreplaceable biomechanical role in mastication dynamics, speech expression, and facial expression control. Clinical data shows that approximately 15% of patients with temporomandibular joint disorder (TMJ) suffer from severe bone defects due to disc perforation or condylar resorption, requiring joint reconstruction to restore function. Traditional TMJ preparation faces three major technical bottlenecks: ① long-term biotoxicity risks due to metal ion release; ② anatomical mismatch caused by polymer creep deformation; ③ the bioinertness of materials hindering the osseointegration process.

[0003] Recent research breakthroughs have shown that silicon nitride ceramics can overcome the limitations of traditional ceramic materials through micro- and nano-scale pore structure design: their elastic modulus can be tuned to the 14-18 GPa range, achieving a gradient match with the mechanical properties of cortical bone; and surface silanol active sites have been confirmed by in vitro mineralization experiments to induce hydroxyapatite deposition. Particularly noteworthy is the unique antibacterial properties exhibited by the three-dimensional interpenetrating network structure of silicon nitride (Si3N4), which stems from the reactive oxygen species burst mechanism induced by its surface electronic states.

[0004] Titanium alloys have significant advantages in the preparation of temporomandibular joint implants, mainly in the following aspects: (1) Excellent biocompatibility: A 5-10 nm TiO2 oxide layer naturally forms on the surface of titanium alloys, which can effectively prevent corrosion and ion release, and avoid immune rejection. (2) Non-toxic: It meets the medical standards of ISO 5832-3 and ASTM F136, and there is no inflammatory reaction in the surrounding tissues after long-term implantation. (3) Mechanical properties match the low modulus of human bone: It is close to the modulus of cortical bone, reducing the stress shielding effect. (4) High strength: The tensile strength and fatigue strength are sufficient to withstand the dynamic load of TMJ. (5) 3D printing customization advantage: Individualized biomimetic design can be realized through SLM / EBM technology, which can accurately match the curvature of the patient's glenoid fossa and the morphology of the condyle. (6) Porous structure integration: Gradient pore structure can be designed to promote bone ingrowth. (7) Long-term durability: The coefficient of friction is as low as 0.15-0.2 after polishing. (8) Anti-fatigue: In the simulated chewing cycle test, the titanium alloy implant showed no obvious cracks or deformation. (9) Good postoperative functional recovery: The density is significantly lower than that of cobalt-chromium alloy, reducing the burden on the joint and improving mouth opening. (10) Biomechanical conduction: The elastic modulus is close to that of natural bone, which helps maintain the normal stress distribution of the jawbone, reduces the risk of loosening of adjacent teeth, and is compatible with modern medical technology. (11) Medical imaging friendly: There are no artifacts in CT / MRI examinations, which facilitates postoperative monitoring. (12) Convenient for secondary surgery: If revision is required, the interface between the titanium alloy and bone tissue is easily separated and does not affect the surrounding blood vessels and nerve bundles. (13) Clinical research support: 10-year follow-up data showed that the success rate of titanium alloy TMJ implants was 92.3%, which was significantly higher than that of cobalt-chromium alloy. (14) Bone integration rate: Micro-CT showed that the bone-implant contact rate reached 75%-85% one year after surgery. Titanium alloys have become the gold standard material for TMJ reconstruction due to their biocompatibility, mechanical adaptability, 3D printing customization capabilities, and long-term stability, and are especially suitable for complex anatomical variations or revision cases. Summary of the Invention

[0005] The purpose of this invention is to provide a 3D printing method for SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implants, which can be used to prepare temporomandibular joint implants with better corrosion resistance, wear resistance and biostability.

[0006] The technical solution adopted by this invention to solve its technical problem is: a 3D printing method for SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implants, comprising the following steps: S1, weighing powder.

[0007] Silicon nitride powder with a size distribution was prepared, and then the graded silicon nitride powder was wet ball-milled, dried and sieved. Sintering aids accounting for 2%-6% of the silicon nitride powder were added to the ball-milled silicon nitride powder and mixed evenly.

[0008] S2, Mixing.

[0009] S2.1 Preparation of photosensitive resin: The photoinitiator is added to the silane coupling agent modified under acidic conditions, and mechanically stirred at 30℃-50℃ for 20 min-40 min to dissolve the photoinitiator in the silane coupling agent modified under acidic conditions. Then, it is allowed to stand for 10 min-20 min until the system is transparent to obtain a homogeneous photosensitive resin, which serves as a precursor for silicon nitride ceramics.

[0010] S2.2 Construction of the dispersion system: Subsequently, a dispersant was added to the photosensitive resin, and the amount of dispersant was 3%-6% of the weight of the photosensitive resin.

[0011] S3. Stir.

[0012] The graded silicon nitride powder obtained in step S1 and the photosensitive resin obtained in step S2.2 are introduced into a mechanical stirring device and stirred for 2-3 hours to obtain a mixture. During stirring, 2%-4% of an organic solvent by weight of the photosensitive resin is added in stages. The organic solvent is one or a mixture of several of butanone, acetone, methanol and ethanol.

[0013] S4, Homogeneous.

[0014] The mixture obtained in step S3 is added to a homogenizer and continuously mixed at a shear rate of 500 rpm to 800 rpm for 10 min to 20 min. The organic solvent is removed at a temperature of 40℃ to 60℃ to finally obtain silicon nitride ceramic slurry.

[0015] S5, Scan Modeling.

[0016] A model of a temporomandibular joint implant with a gradient porous structure was established.

[0017] S6. Print.

[0018] The silicon nitride ceramic slurry obtained in step S4 is placed in a 3D printer containing the temporomandibular joint implant model obtained in step S5, and 3D printing is performed to obtain a temporomandibular joint implant print, followed by cleaning and drying.

[0019] S7, Sintering.

[0020] The temporomandibular joint implant printout obtained in step S6 is sintered.

[0021] S8. Assembly.

[0022] The composite silicon nitride ceramic and the titanium alloy matrix are fixed together by tenon and mortise joint to obtain the SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implant.

[0023] Furthermore, the weight percentage of small-particle-size silicon nitride powder is 30%-40%, and the weight percentage of large-particle-size silicon nitride powder is 60%-70%.

[0024] Furthermore, the sintering aid is yttrium oxide, lanthanum oxide, or cerium oxide.

[0025] Furthermore, the silane coupling agent is KH550, KH560, or KH570.

[0026] Furthermore, the photoinitiator is one or more of 1-hydroxycyclohexylphenyl ketone, benzoin dimethyl ether, benzophthalate ester or phthalyl benzoyl oxide, and the content of the photoinitiator is 2%-4% of the weight of the modified silane coupling agent.

[0027] Further, the dispersant is one or more of BYK103, BYK106, BYK110, BYK111, and BYK130.

[0028] Furthermore, the mechanical stirring equipment includes a water bath, a three-necked flask, a condenser, and a stirring motor. The three-necked flask is located inside the water bath. The three-necked flask has three ports: the first port is the feeding port for adding organic solvents; the second port connects to the condenser; the stirring motor is located above the third port, and its output end has a stirring paddle that extends into the three-necked flask through the third port. The water bath has a support rod, on which a oscillating motor is mounted. The output shaft of the oscillating motor is fixedly mounted to a bracket with clips, and the three-necked flask is secured to the bracket via these clips. When the oscillating motor operates, it drives the three-necked flask to oscillate periodically via its output shaft.

[0029] Furthermore, the gradient porous structure type is one or more structural combinations of lattice structure, three-period minimal surface, honeycomb structure, and Thiessen polygon structure.

[0030] Furthermore, the specific steps of step S5 include: S5.1 Perform a CT scan on the human temporomandibular joint and reverse model it to obtain a temporomandibular joint implant model that fits precisely with the patient's bones.

[0031] S5.2 Based on the anatomical structure of the temporomandibular joint, the temporomandibular joint implant model is divided into a dense area, a transitional area, and a porous area. The dense area accounts for 10%-40% of the overall structure, the transitional area accounts for 20%-80% of the overall structure, and the porous area accounts for 10%-40% of the overall structure.

[0032] S5.3. Biomechanical simulation analysis of the temporomandibular joint implant model with gradient porous structure was performed using Ansys finite element software.

[0033] S5.4. Thermodynamic simulation of the temporomandibular joint implant model with gradient porous structure is performed using simulation software to avoid cracks caused by different shrinkage rates in different directions during subsequent sintering, and to make local adjustments to parts that do not meet the requirements.

[0034] Furthermore, the cleaning process involves ultrasonic cavitation cleaning, specifically: using a 40kHz ultrasonic cleaner with 99.7% isopropanol as the medium, and treating for 30 minutes at a constant temperature of 25±2℃ to effectively remove uncured resin and micron-sized particle residues from the surface.

[0035] Furthermore, the drying process is as follows: in the initial drying stage, the product is placed in a 50℃ hot air circulating drying oven for 2 hours to achieve a humidity of ≤20%; in the fine drying stage, it is transferred to a constant temperature and humidity chamber for equilibration treatment for 8 hours.

[0036] Furthermore, the specific sintering method is as follows: sintering is carried out in a muffle furnace with argon or nitrogen gas at a temperature of 1400℃-1500℃ to obtain composite silicon nitride ceramics with excellent biological activity.

[0037] The beneficial effects of this invention are as follows: This invention uses KH570-H / Si3N4 photosensitive ceramic slurry with a solid content of 50wt% to prepare a KH570-H / Si3N4 slurry by using KH570 modified precursor resin and graded silicon nitride powder. After printing and sintering, a photothermal SiOC / Si3N4 composite ceramic temporomandibular joint implant is formed. Experiments show that the composite ceramic temporomandibular joint implant exhibits the best comprehensive performance, possessing both the highest density and excellent photothermal effect. Its porous structure design effectively balances the mechanical stability of the articular surface and the bioactivity requirements of the osteointegration surface. Biological evaluation confirms that this composite material has good biocompatibility. Below 50 °C, it promotes osteoblast proliferation through thermal stimulation, activates antibacterial function in the 50-60 °C range, and the cyclic stability coefficient indicates that its photothermal performance does not significantly decrease. The use of precursor method reduces sintering temperature and time; dense-porous structure design and 3D printing achieve functional integration of articular surface stability and osseointegration of silicon nitride ceramic temporomandibular joint implants, reducing elastic modulus; biomechanics and osseointegration are controlled by changing the porous parameters of silicon nitride ceramics, enabling customized preparation of bioceramic implants. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the silicon nitride ceramic slurry processing of the present invention; Figure 2 This invention relates to the processing principle of the gradient porous structure of the temporomandibular joint. Figure 3 Flowchart of the overall preparation process for temporomandibular joint implants; Figure 4 The post-printing and processing flow for temporomandibular joint implants; Figure 5 A schematic diagram of the gradient porous structure of a temporomandibular joint implant; In the figure: 1. Titanium alloy substrate, 2. Composite silicon nitride ceramic, 3. Threaded hole. Detailed Implementation

[0039] The 3D printing method of the SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implant of the present invention will be described in detail below with reference to the accompanying drawings.

[0040] like Figures 1 to 3 As shown, the 3D printing method for SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implants includes the following steps: S1, weighing powder.

[0041] A mixture of silicon nitride powders with varying size distributions is prepared, wherein small-diameter silicon nitride powder accounts for 30%-40% by weight and large-diameter silicon nitride powder accounts for 60%-70% by weight. For example, 500nm silicon nitride powder and 1μm-3μm silicon nitride powder are graded in a 4:6 ratio, and then the graded silicon nitride powder is wet-ball-milled for 4-12 hours, dried, and sieved.

[0042] The silicon nitride powder obtained by ball milling is the basic component. 2%-6% of sintering aids, such as yttrium oxide, lanthanum oxide, or cerium oxide, are added to the basic component and mixed evenly.

[0043] This process improves the bulk density of powder through size gradient distribution and optimizes the ceramic sintering densification process by combining the liquid-phase synergistic effect of sintering aids.

[0044] S2, Mixing.

[0045] S2.1 Preparation of photosensitive resin: The photoinitiator is added to the silane coupling agent modified under acidic conditions. The mixture is mechanically stirred at 30℃-50℃ for 20 min-40 min to dissolve the photoinitiator in the silane coupling agent modified under acidic conditions. Then, the mixture is allowed to stand for 10 min-20 min until the system becomes transparent to obtain a homogeneous photosensitive resin, which serves as a precursor for silicon nitride ceramics to achieve resin-powder interface bonding strengthening.

[0046] The silane coupling agent can be KH550, KH560 or KH570.

[0047] The photoinitiator is one or more of 1-hydroxycyclohexylphenyl ketone, benzoin dimethyl ether, benzyl phthalate ester or phthalyl phthalide oxide, and the content of the photoinitiator is 2%-4% of the weight of the modified silane coupling agent.

[0048] S2.2 Construction of the dispersion system: Then, a dispersant is added to the photosensitive resin. The dispersant is selected from one or more of the BYK series, such as BYK103, BYK106, BYK110, BYK111, and BYK130. The amount of dispersant is 3%-6% of the weight of the photosensitive resin.

[0049] This process improves the compatibility between the slurry and silicon nitride powder by modifying the silane coupling agent precursor, and achieves nanoscale distribution in the silicone resin by combining a gradient dispersion strategy, thus ensuring the coordinated control of photocuring printing accuracy and photothermal function.

[0050] S3. Stir.

[0051] The graded silicon nitride powder obtained in step S1 and the photosensitive resin obtained in step S2.2 are introduced into a mechanical stirring device and stirred mechanically for 2-3 hours at a speed of 1500-2000 r / min to obtain a mixture. During stirring, an organic solvent, accounting for 2%-4% of the weight of the photosensitive resin, is added in stages to ensure that the rheological properties of the material system meet the requirements of subsequent processing. The organic solvent is one or a mixture of several of butanone, acetone, methanol, and ethanol.

[0052] The mechanical stirring device includes a water bath, a three-necked flask, a condenser, and a stirring motor. The three-necked flask is located inside the water bath. The flask has three ports: the first port is the feeding port for adding organic solvents; the second port connects to the condenser; the stirring motor is located above the third port, and its output end has a stirring paddle that extends into the flask through the third port. The water bath has a support rod, on which a oscillating motor is mounted. The output shaft of the oscillating motor is fixedly mounted to a bracket with clips, and the flask is secured to the bracket using these clips. When the oscillating motor operates, it drives the flask to oscillate periodically via its output shaft.

[0053] S4, Homogeneous.

[0054] The mixture obtained in step S3 is added to a homogenizer and continuously mixed at a shear rate of 500 rpm-800 rpm for 10-20 minutes. The organic solvent is then removed at a temperature of 40℃-60℃, ultimately yielding a silicon nitride ceramic slurry with a viscosity of 2-5 Pa·s and a solid content of 40wt%-60wt%. This process optimizes the rheological properties of the slurry through the synergistic effect of dynamic mechanical shearing and thermal field, ensuring uniform dispersion of Si3N4 particles and the modified resin phase, thus meeting the requirements for leveling and interlayer bonding strength in SLA printing.

[0055] S5, Scan Modeling.

[0056] A model of a temporomandibular joint implant with a gradient porous structure was established. The porous type is one or more structural combinations of lattice structure, three-period minimal surface, honeycomb structure, and Thiessen polygon structure.

[0057] S5.1 Perform a CT scan of the temporomandibular joint (TMJ) and reverse engineer it to obtain a TMJ implant model that precisely fits the patient's bone structure. For example, use Mimics software to perform 3D reconstruction of the CT images of the ward area, and use GeomagicDesign software to design a macroscopic model of the TMJ prosthesis that precisely fits the patient's bone structure.

[0058] S5.2. Based on the anatomical structure of the temporomandibular joint (TMJ) and drawing on the transitional characteristics of cortical bone-cancellous bone porosity, the TMJ implant model is divided into a dense zone, a transitional zone, and a porous zone. The dense zone accounts for 10%-40% of the overall structure, the transitional zone for 20%-80%, and the porous zone for 10%-40%. The porous zone is further divided into macropore and micropore zones, achieving a dense-macropore-micropore design for the articular surface-retention surface. The retention surface is designed with a dense-micropore structure, the friction surface with a smooth and dense structure to improve stability, and the retention surface with a porous structure to promote healing and later stabilization. The pore size should facilitate cell ingrowth. The macropore zone accounts for 5%-20% of the overall structure, and the micropore zone for 5%-20%.

[0059] S5.3. Biomechanical simulation analysis of the temporomandibular joint implant model with gradient porous structure was performed using Ansys finite element software to ensure that the gradient porous structure meets the growth requirements of bone cells while matching the stress experienced by the human body.

[0060] S5.4. Thermodynamic simulation of the temporomandibular joint implant model with a gradient porous structure is performed using simulation software to prevent cracks from forming during subsequent sintering due to varying shrinkage rates in different directions. Local adjustments are made to areas that do not meet requirements, such as increasing the rod diameter in areas with high stress or high shrinkage. The pore size and rod diameter of the gradient porous structure both exhibit a gradient variation of 0.1mm-1mm, with a porosity ranging from 20% to 80%.

[0061] S6. Print.

[0062] like Figure 4As shown, the silicon nitride ceramic slurry obtained in step S4 is placed in a 3D printer containing the temporomandibular joint implant model obtained in step S5, and 3D printing is performed to obtain a printed temporomandibular joint implant. Subsequently, a two-stage post-processing is performed: ① Ultrasonic cavitation cleaning: A 40kHz ultrasonic cleaner is used with 99.7% isopropanol as the medium, and the process is carried out at a constant temperature of 25±2℃ for 30 minutes to effectively remove uncured resin and micron-sized particle residues from the surface. ② Drying control: During the initial drying stage, the material is placed in a 50℃ hot air circulating drying oven for 2 hours to ensure humidity ≤20%; during the fine drying stage, the material is transferred to a constant temperature and humidity chamber for equilibration treatment for 8 hours.

[0063] S7, Sintering.

[0064] The temporomandibular joint implant printout obtained in step S6 is sintered, specifically in a muffle furnace purged with argon or nitrogen at a temperature of 1400℃-1500℃ to obtain a composite silicon nitride ceramic with excellent bioactivity. During this process, the silane coupling agent is converted into an amorphous SiOC phase via pyrolysis and carbonization. The sp² hybrid carbon network formed in this phase endows the material with significant photothermal response characteristics, allowing it to heat up to 50℃-60℃ within 5-10 minutes under 808nm near-infrared laser irradiation, thus meeting the dual requirements for osseointegration and antibacterial function.

[0065] The sintering process includes the following reaction processes: (1) Methoxyl hydrolysis and silanol condensation; In the initial heating stage of sintering, the methoxy-OCH3 of KH570-H first undergoes hydrolysis to generate silanol Si-OH and release methanol. Subsequently, the silanol forms a three-dimensional Si-O-Si network structure through condensation reaction: Si-OCH3+H2O→Si-OH+CH3OH, Si-OCH3+H2O→Si-OH+CH3OH, 2Si-OH→Si-O-Si+H2O, 2Si-OH→Si-O-Si+H2O. This stage forms an inorganic silicon-oxygen framework, providing a structural basis for subsequent carbothermal reduction. (2) Methacryloyloxyl pyrolysis and carbonization; As the temperature rises, the methacryloyloxyl group undergoes pyrolysis, and the methacryloyl group decomposes to generate CO2 and propylene free radical CH2=CH. The free radical further crosslinks to form a carbon chain structure. The organic carbon chain is carbonized in an inert atmosphere to generate amorphous carbon or graphene quantum dots, which combine with the silicon-oxygen framework to form a carbon-silicon composite phase. (3) Carbothermic reduction and SiOC phase formation: During the high-temperature sintering stage, SiO2 undergoes a carbothermic reduction reaction with carbon to generate an amorphous SiOC phase: SiO2 + C → SiOC + CO↑. The phase is composed of a Si-OC bond network, in which the presence of oxygen vacancies and sp² hybrid carbon endows the material with photothermal response characteristics. Raman spectroscopy shows that the D / G peak intensity ratio is 1.25, indicating the formation of a partially graphitized carbon structure.

[0066] The dense structure of SiOC after high-temperature treatment indicates that the Si-OC ternary network is fully cross-linked and stabilized at high temperatures. Its dense and uniform structure helps to improve the thermal stability and mechanical properties of the material. KH570, through a staged pyrolysis-carbonization-reduction reaction, ultimately forms a SiOC / silicon nitride composite ceramic with both mechanical and functional properties.

[0067] S8. Assembly.

[0068] like Figure 5 As shown, the composite silicon nitride ceramic 2 and the titanium alloy substrate 1 are fixed together by tenon and mortise joints, and the titanium alloy substrate 1 is fixed together by screws to obtain a SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implant. For this purpose, multiple threaded holes 3 are provided on the aluminum alloy substrate 1.

[0069] This invention utilizes KH570-H / Si3N4 photosensitive ceramic slurry with a solid content of 50 wt% prepared from KH570 modified precursor resin and graded silicon nitride powder. After printing and sintering, a photothermal SiOC / Si3N4 composite ceramic temporomandibular joint implant is formed. Experiments show that the composite ceramic temporomandibular joint implant exhibits optimal comprehensive performance, possessing both the highest density and excellent photothermal effect. Its porous structure effectively balances the mechanical stability of the articular surface and the bioactivity requirements of the osteointegration surface. Biological evaluation confirms that the composite material has good biocompatibility; below 50 °C, thermal stimulation promotes osteoblast proliferation, while in the 50-60 °C range, it activates antibacterial function, and the cyclic stability coefficient indicates that its photothermal performance does not significantly decline. The use of precursor method reduces sintering temperature and time; dense-porous structure design and 3D printing achieve functional integration of articular surface stability and osseointegration of silicon nitride ceramic temporomandibular joint implants, reducing elastic modulus; biomechanics and osseointegration are controlled by changing the porous parameters of silicon nitride ceramics, enabling customized preparation of bioceramic implants.

Claims

1. A 3D printing method for SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implants, characterized in that, Includes the following steps: S1. Weighing the powder; Silicon nitride powder with a size distribution was mixed, and then the size distribution silicon nitride powder was wet ball milled, dried and sieved; 2%-6% of sintering aid was added to the silicon nitride powder obtained by ball milling and mixed evenly. S2, Mixing; S2.1 Preparation of photosensitive resin: The photoinitiator is added to the silane coupling agent modified under acidic conditions, and mechanically stirred at 30℃-50℃ for 20 min-40 min to dissolve the photoinitiator in the silane coupling agent modified under acidic conditions. Then, it is allowed to stand for 10 min-20 min until the system is transparent to obtain a homogeneous photosensitive resin, which serves as a precursor for silicon nitride ceramics. S2.2 Construction of the dispersion system: Subsequently, a dispersant was added to the photosensitive resin, and the amount of the dispersant was 3%-6% of the weight of the photosensitive resin; S3. Stir; The graded silicon nitride powder obtained in step S1 and the photosensitive resin obtained in step S2.2 are introduced into a mechanical stirring device and stirred for 2-3 hours to obtain a mixture; during stirring, an organic solvent accounting for 2%-4% of the weight of the photosensitive resin is added in stages. S4, homogenization; The mixture obtained in step S3 is added to a homogenizer and continuously mixed at a shear rate of 500 rpm-800 rpm for 10 min-20 min. The organic solvent is removed at a temperature of 40℃-60℃ to finally obtain silicon nitride ceramic slurry. S5, Scan Modeling; Establish a model of a temporomandibular joint implant with a gradient porous structure; S6, Print; The silicon nitride ceramic slurry obtained in step S4 is placed in a 3D printer containing the temporomandibular joint implant model obtained in step S5, and 3D printing is performed to obtain a temporomandibular joint implant print, followed by cleaning and drying. S7, sintering; The temporomandibular joint implant print obtained in step S6 is sintered. S8. Assembly; The composite silicon nitride ceramic and the titanium alloy matrix are fixed together by tenon and mortise joint to obtain the SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implant.

2. The 3D printing method for SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implants according to claim 1, characterized in that, In step S1, the weight percentage of small-particle-size silicon nitride powder is 30%-40%, and the weight percentage of large-particle-size silicon nitride powder is 60%-70%.

3. The 3D printing method for SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implants according to claim 1, characterized in that, In step S1, the sintering aid is yttrium oxide, lanthanum oxide, or cerium oxide.

4. The 3D printing method for SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implants according to claim 1, characterized in that, In step S2.1, the silane coupling agent is KH550, KH560 or KH570.

5. The 3D printing method for SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implants according to claim 1, characterized in that, In step S2.1, the photoinitiator is one or more of 1-hydroxycyclohexylphenyl ketone, benzoin dimethyl ether, benzyl phthalate ester or phthalyl phthalide oxide, and the content of the photoinitiator is 2%-4% of the weight of the modified silane coupling agent.

6. The 3D printing method for SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implants according to claim 1, characterized in that, In step S2.2, the dispersant is one or more of BYK103, BYK106, BYK110, BYK111, and BYK130.

7. The 3D printing method for SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implants according to claim 1, characterized in that, In step S3, the mechanical stirring device includes a water bath, a three-necked flask, a condenser, and a stirring motor. The three-necked flask is located inside the water bath. The three-necked flask has three ports: the first port is the feeding port for adding organic solvent; the second port is connected to the condenser; the stirring motor is located above the third port of the three-necked flask, and its output end has a stirring paddle that extends into the three-necked flask through the third port; the water bath has a support rod, on which a swing motor is mounted. The output shaft of the swing motor is fixedly mounted on a bracket with clips, and the three-necked flask is mounted on the bracket via the clips; when the swing motor is working, it drives the three-necked flask to swing periodically back and forth through its output shaft.

8. The 3D printing method for SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implants according to claim 1, characterized in that, In step S4, the organic solvent is one or a mixture of several of butanone, acetone, methanol and ethanol.

9. The 3D printing method for SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implants according to claim 1, characterized in that, In step S5, the gradient porous structure type is one or more combinations of lattice structure, three-period minimal surface, honeycomb structure, and Thiessen polygon structure.

10. The 3D printing method for SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implants according to claim 1, characterized in that, The specific steps of step S5 include: S5.1 Perform a CT scan on the human temporomandibular joint and reverse model it to obtain a temporomandibular joint implant model that fits precisely with the patient's bones; S5.2 Based on the anatomical structure of the temporomandibular joint, the temporomandibular joint implant model is divided into a dense area, a transitional area, and a porous area. The dense area accounts for 10%-40% of the overall structure, the transitional area accounts for 20%-80% of the overall structure, and the porous area accounts for 10%-40% of the overall structure. S5.

3. Biomechanical simulation analysis of the temporomandibular joint implant model with gradient porous structure was performed using Ansys finite element software. S5.

4. Thermodynamic simulation of the temporomandibular joint implant model with gradient porous structure is performed using simulation software to avoid cracks caused by different shrinkage rates in different directions during subsequent sintering, and to make local adjustments to parts that do not meet the requirements.

11. The 3D printing method for SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implants according to claim 1, characterized in that, In step S6, the cleaning is ultrasonic cavitation cleaning, specifically: using a 40kHz ultrasonic cleaner with 99.7% isopropanol as the medium, and treating for 30 minutes at a constant temperature of 25±2℃, effectively removing uncured resin and micron-sized particle residues from the surface.

12. The 3D printing method for SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implants according to claim 1, characterized in that, In step S6, the drying process is as follows: during the initial drying stage, the product is placed in a 50℃ hot air circulating drying oven for 2 hours to achieve a humidity of ≤20%; during the fine drying stage, it is transferred to a constant temperature and humidity chamber for equilibration treatment for 8 hours.

13. The 3D printing method for SiOC / Si3N4 composite ceramic-titanium alloy temporomandibular joint implants according to claim 1, characterized in that, In step S7, the specific sintering method is as follows: sintering is carried out in a muffle furnace with argon or nitrogen gas at a temperature of 1400℃-1500℃ to obtain composite silicon nitride ceramics with excellent biological activity.

Images