Preparation method of 3D printing PEEK network stent for repairing large-scale defect of mandible

Abstract

The invention discloses a preparation method of a 3D printing PEEK network stent for repairing large-scale defects of lower jawbone, and belongs to the field of biomedical engineering and mouth rehabilitation, and the preparation method comprises the following steps: reversely deducing the elastic modulus required by the stent in a specific area according to local stress distribution by introducing a mechanical calculation formula, further optimizing the microstructure of the stent, and obtaining the 3D printing PEEK network stent for repairing the large-scale defects of the lower jawbone. And the stent can dynamically meet the growth requirement of bone tissues in the whole repair process, so that the regeneration of endogenous bones and blood vessels is effectively promoted.

Description

Technical Field

[0001] This invention belongs to the fields of biomedical engineering and oral restoration, and particularly relates to a method for preparing a 3D-printed PEEK network scaffold for repairing large-scale defects in the mandible. Background Technology

[0002] Repairing large mandibular defects has always been a major challenge in the field of oral medicine. Traditional restorative methods typically rely on autologous bone grafting or total prosthesis implantation, but these methods have several significant problems. While autologous bone grafting offers good biocompatibility, it involves significant donor site trauma and unpredictable long-term efficacy, especially when the defect area is too large, as the quantity and quality of donor bone may not meet the requirements. Although prosthesis implantation avoids the above problems, its poor biomechanical compatibility with the host bone often leads to stress shielding, thus affecting bone regeneration and repair outcomes.

[0003] Although some 3D-printed scaffolds employ porous structures to improve their adaptability to host bone, these scaffolds still cannot fully meet the optimal mechanical stimulation requirements during bone regeneration due to a lack of precise design for the mechanical environment. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for fabricating a 3D-printed PEEK network scaffold for repairing large-scale defects in the mandible, comprising:

[0005] Based on the patient's CT medical imaging data, a three-dimensional model of the mandible containing the bone defect area was constructed, and the macroscopic shape of the framework was designed based on the three-dimensional model.

[0006] Based on the three-dimensional model of the mandible and the macroscopic shape of the scaffold, a finite element model including the mandible and the scaffold is established, and loads and constraints simulating physiological states are applied to the finite element model to obtain stress distribution data of the scaffold and bone tissue after implantation.

[0007] Calculate the target strain of each local area of ​​the support based on the stress distribution data, and deduce the target elastic modulus required for the corresponding area of ​​the support based on the target strain;

[0008] Based on the target elastic modulus, the porosity and pore size distribution of the support in different regions are adjusted to generate a non-uniform porous structure model with spatially varying mechanical properties.

[0009] The non-uniform porous structure model is imported into a 3D printing device, and a network scaffold is printed using PEEK material. The printed scaffold is then post-processed to obtain a final product that can be implanted.

[0010] Optionally, the construction of the three-dimensional model of the mandible is achieved by reconstructing the CT medical image data in three dimensions using medical image reverse engineering technology and computer-aided design technology.

[0011] Optionally, the applied load is a physiological load simulating human biting force, and the constraint condition is to fix the edge region of the mandibular model.

[0012] 4. The method according to claim 1, characterized in that the derivation of the target elastic modulus based on the target strain is achieved through the following iterative optimization process:

[0013] a) Set an initial elastic modulus for each element in the porous region of the support, the value of which is between the lowest elastic modulus achievable by porous PEEK and the elastic modulus of solid PEEK.

[0014] b) Perform finite element analysis based on the current elastic modulus of each element to obtain the current strain of each element, and count the proportion of elements whose current strain falls within the preset ideal strain range.

[0015] c) Determine whether the ratio has reached a preset threshold. If yes, terminate the iteration and use the current elastic modulus as the target elastic modulus. If no, calculate the strain deviation of each element that does not fall into the ideal strain range and generate an update factor accordingly.

[0016] d) Based on the update factor and the preset step size, update and adjust the elastic modulus of each unit, and limit the adjusted modulus value to the range formed by the lowest elastic modulus and the solid PEEK elastic modulus;

[0017] e) Return to step b) for the next iteration until the termination condition is met.

[0018] Optionally, the adjustment of porosity and pore size distribution based on the target elastic modulus is performed according to a pre-established database that characterizes the relationship between the porosity, pore size and equivalent elastic modulus of PEEK materials.

[0019] Optionally, the post-processing includes sequentially performing surface polishing, cleaning, and sterilization on the printed bracket.

[0020] Optionally, the non-uniform porous structure model enables the final printed PEEK scaffold to have a spatially varying porosity and pore size gradient distribution according to mechanical requirements.

[0021] On the other hand, the present invention also provides an electronic device including a memory, a processor, and a computing program stored in the memory and executable on the processor, wherein the processor implements the method when executing the computing program.

[0022] On the other hand, the present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method.

[0023] Compared with the prior art, the present invention has the following advantages and technical effects:

[0024] This invention proposes a personalized mandibular bone repair scaffold design method based on a stress-strain feedback mechanism through innovative mechanical calculation formulas. This method can accurately calculate and back-calculate the required elastic modulus of the mandibular bone defect area, and then precisely control the mechanical properties of the scaffold by adjusting its porosity and pore size distribution. Compared with traditional technologies, the scaffold design of this invention can dynamically adapt to changes in mechanical requirements during bone regeneration, thereby effectively promoting the regeneration of endogenous bone and blood vessels.

[0025] PEEK scaffolds fabricated using 3D printing technology possess spatially variable mechanical properties, enabling them to better match the host bone and improve repair efficiency and long-term stability. This innovative technology offers a new solution for the repair of large-scale mandibular bone defects and holds significant promise for clinical applications. Attached Figure Description

[0026] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0027] Figure 1 This is a schematic diagram of the method flow according to an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the formation of a grid-like blood vessel according to an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the implantable stent according to an embodiment of the present invention. Detailed Implementation

[0030] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0032] Example 1

[0033] like Figure 1As shown, this embodiment provides a method for fabricating a 3D-printed PEEK network scaffold for repairing large-scale defects in the mandible, comprising:

[0034] A three-dimensional model of the mandible was constructed based on CT medical imaging data, and the macroscopic shape of the framework was designed.

[0035] A finite element model containing the scaffold and bone tissue was established and physiological loads and boundary conditions were applied to obtain stress distribution data.

[0036] Calculate the local target strain based on the stress distribution data, and deduce the required elastic modulus for each region.

[0037] Based on the target elastic modulus, the porosity and pore size distribution of different regions of the support are adjusted to form a non-uniform porous structure.

[0038] The optimized model is imported into a 3D printing device to print a PEEK scaffold, and post-processing is performed to obtain the target implant.

[0039] This embodiment addresses the shortcomings of existing mandibular repair scaffolds in terms of mechanical compatibility, vascularization capacity, and osteogenic induction. It proposes a personalized scaffold design method based on a stress-strain feedback mechanism. Through a set of innovative mechanical calculation formulas, it achieves precise matching of the scaffold's elastic modulus, thereby promoting endogenous bone and blood vessel regeneration without the need for exogenous growth factors.

[0040] The core of this embodiment lies in using a set of innovative mechanical calculation formulas to deduce the ideal elastic modulus required by the scaffold in the mandibular defect area based on the local stress distribution in that area, thereby achieving precise control of the mechanical microenvironment and guiding blood vessel and tissue regeneration.

[0041] This embodiment includes the following core calculation formulas:

[0042] Step 1: ;

[0043] in, It is the elastic modulus of the element numbered i in the porous region during the k-th iteration. This is the lowest elastic modulus achievable with porous PEEK. It is the elastic modulus of solid PEEK.

[0044] Step 2: Determine whether the strain in the porous region meets the requirements;

[0045] definition ;

[0046] in, ; ; N is the total number of all units in the porous region.

[0047] Then: if If the iteration terminates, proceed to step 3; otherwise, continue to step 3.

[0048] Step 3: Calculate the update factor for each unit;

[0049] ;

[0050] Step 4: Update the elastic modulus ;

[0051] in, To update the step size, if Increased modulus Modulus decreases The modulus remains unchanged.

[0052] Step 5: Remove out-of-range moduli;

[0053] That is: if the result obtained in step 5 Then the value is assigned to , Then the value is assigned to Return to step 1.

[0054] Example scenario setting:

[0055] Suppose we have a porous region containing 5 units, with the initial elastic modulus uniformly set as follows:

[0056] ;

[0057] The ideal range of strain is:

[0058] ;

[0059] The iteration termination condition is set as follows:

[0060] ;

[0061] Update step size set to:

[0062] ;

[0063] Initial strain data (from finite element analysis) are shown in Table 1:

[0064] Table 1

[0065] Unit No. initial strain ( ) 1 12000 2 18000 3 9000 4 15000 5 16000

[0066] Iterative calculation process (round 1):

[0067] Step 1: Check the modulus range:

[0068] initial ,exist The contents meet the requirements.

[0069] Step 2: Determine the strain compliance rate:

[0070] definition: ;

[0071] calculate:

[0072] Unit 1: 12000 Within the range S=1;

[0073] Unit 2: 18000 Out of range S=0;

[0074] Unit 3: 9000 is below the range S=0;

[0075] Unit 4: 15000 Within the range S=1;

[0076] Unit 5: 16000 Within the range S=1;

[0077] ;

[0078] Continue to step 3.

[0079] Step 3: Calculate the update factor:

[0080] ;

[0081] calculate:

[0082] Unit 1: Within the range ;

[0083] Unit 2: ;

[0084] Unit 3: ;

[0085] Unit 4: Within the range ;

[0086] Unit 5: Within the range ;

[0087] Step 4: Update the elastic modulus:

[0088] ;

[0089] calculate:

[0090] ;

[0091] ;

[0092] ;

[0093] ;

[0094] ;

[0095] Step 5: Limit the modulus range:

[0096] All values ​​remain within [200, 1961] and require no adjustment.

[0097] Assume the strain data from the second round (obtained through finite element analysis based on the updated modulus) is as shown in Table 2:

[0098] Table 2

[0099] unit ( ) 1 12500 2 17200 3 9800 4 15500 5 16500

[0100] Second iteration;

[0101] Step 2: Strain compliance rate;

[0102] Unit 1: 12500 → Within the range → 1;

[0103] Unit 2: 17200 → Within the range → 1;

[0104] Unit 3: 9800 → Below range → 0;

[0105] Unit 4: 15500 → Within the range → 1;

[0106] Unit 5: 16500 → Within the range → 1;

[0107] ;

[0108] Iteration terminated;

[0109] The final elastic modulus distribution is shown in Table 3;

[0110] Table 3

[0111] unit Final elastic modulus (MPa) 1 600 2 618.54 3 579.3 4 600 5 600

[0112] As can be seen from the simulation example above, this method iteratively adjusts the elastic modulus of each element, gradually bringing the strain into the ideal osteogenic / vascularization range (10000-17500). ).

[0113] Modulus adjustment is based on the degree to which strain deviates from the ideal range, and is achieved by updating the factor. Achieve adaptive correction.

[0114] The final result is a scaffold design with a non-uniform modulus distribution, achieving "mechanical gradient matching" and promoting bone and blood vessel regeneration.

[0115] This calculation process can be automated and is suitable for the personalized design of complex three-dimensional scaffolds, providing a precise means of mechanical control for the repair of large-scale defects in the mandible.

[0116] By applying this set of formulas point by point or region by region, this embodiment can generate a scaffold design with a non-uniformly distributed elastic modulus in space, that is, an intelligent scaffold that achieves "dynamic matching" and "gradient adaptation" with the host bone in terms of mechanics, as shown in Table 4.

[0117] Table 4

[0118] Porosity / % 0 30 60 80 Aperture / mm 0 0.4 0.6 1.4 Equivalent elastic modulus / MPa 1961 607.4 412.3 202.1 Equivalent yield strength / MPa 90 24.7 16.6 7

[0119] Based on the above core methods, the technical solution of this embodiment includes the following steps:

[0120] Mandibular model construction and prosthesis design: Based on CT data, a three-dimensional model of the mandible is constructed through formula calculation and CAD technology, and the macroscopic shape of the personalized scaffold is designed in combination with the bone defect.

[0121] Finite element modeling and mechanical analysis: A finite element model containing the scaffold and bone tissue is established, physiological loads and boundary conditions are applied, and the stress distribution of the entire scaffold area and the local stress at each point are analyzed.

[0122] Elastic modulus back-calculation and structural optimization: Using the above formula set, the required elastic modulus for each region is back-calculated based on the stress distribution. Guided by this, the porosity and pore size distribution of different regions are adjusted to achieve precise spatial control of the mechanical properties of the stent, ensuring that the strain field generated after implantation is mostly within the optimal angiogenesis range of 10000–17500 με.

[0123] 3D Printing and Post-processing: The optimized model is imported into a high-precision 3D printing device to prepare a PEEK network scaffold, which is then polished, cleaned, and sterilized before being implanted.

[0124] like Figure 2 and Figure 3 As shown, in a rabbit mandibular bone defect model, implantation of a 60% porosity PEEK scaffold can form a mesh-like blood vessel within one month.

[0125] On the other hand, this embodiment also provides an electronic device, including a memory, a processor, and a computing program stored in the memory and executable on the processor, wherein the processor implements the method when executing the computing program.

[0126] On the other hand, this embodiment also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method.

[0127] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for fabricating a 3D-printed PEEK network scaffold for repairing large-scale defects in the mandible, characterized in that, include: Based on the patient's CT medical imaging data, a three-dimensional model of the mandible containing the bone defect area was constructed, and the macroscopic shape of the framework was designed based on the three-dimensional model. Based on the three-dimensional model of the mandible and the macroscopic shape of the scaffold, a finite element model including the mandible and the scaffold is established, and loads and constraints simulating physiological states are applied to the finite element model to obtain stress distribution data of the scaffold and bone tissue after implantation. Calculate the target strain of each local area of ​​the support based on the stress distribution data, and deduce the target elastic modulus required for the corresponding area of ​​the support based on the target strain; Based on the target elastic modulus, the porosity and pore size distribution of the support in different regions are adjusted to generate a non-uniform porous structure model with spatially varying mechanical properties. The non-uniform porous structure model is imported into a 3D printing device, and a network scaffold is printed using PEEK material. The printed scaffold is then post-processed to obtain a final product that can be implanted.

2. The method according to claim 1, characterized in that, The construction of the three-dimensional model of the mandible is achieved by reconstructing the CT medical image data in three dimensions using medical image reverse engineering technology and computer-aided design technology.

3. The method according to claim 1, characterized in that, The applied load is a physiological load simulating the human biting force, and the constraint condition is to fix the edge region of the mandibular model.

4. The method according to claim 1, characterized in that, The derivation of the target elastic modulus based on the target strain is achieved through the following iterative optimization process: a) Set an initial elastic modulus for each element in the porous region of the support, the value of which is between the lowest elastic modulus achievable by porous PEEK and the elastic modulus of solid PEEK. b) Perform finite element analysis based on the current elastic modulus of each element to obtain the current strain of each element, and count the proportion of elements whose current strain falls within the preset ideal strain range. c) Determine whether the ratio has reached a preset threshold. If so, terminate the iteration and take the current elastic modulus as the target elastic modulus. If not, calculate the strain deviation of each element that does not fall within the ideal strain range, and generate an update factor accordingly; d) Based on the update factor and the preset step size, update and adjust the elastic modulus of each unit, and limit the adjusted modulus value to the range formed by the lowest elastic modulus and the solid PEEK elastic modulus; e) Return to step b) for the next iteration until the termination condition is met.

5. The method according to claim 1, characterized in that, The adjustment of porosity and pore size distribution based on the target elastic modulus is carried out according to a pre-established database that characterizes the relationship between the porosity, pore size and equivalent elastic modulus of PEEK materials.

6. The method according to claim 1, characterized in that, The post-processing includes sequentially performing surface polishing, cleaning, and sterilization on the printed bracket.

7. The method according to claim 1, characterized in that, The non-uniform porous structure model enables the final printed PEEK scaffold to have a spatially varying porosity and pore size gradient distribution according to mechanical requirements.

8. An electronic device comprising a memory, a processor, and a computing program stored in the memory and executable on the processor, characterized in that, When the processor executes the computing program, it implements the method of any one of claims 1-7.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1-7.

Images