Lip-cheek side and palatal side double-retention subperiosteal implant stent and manufacturing method

Abstract

The invention discloses a lip-cheek side and palatal side double-retention subperiosteal implant stent and a manufacturing method, the implant stent comprises a double-retention stent main body, one side of the double-retention stent main body is provided with a screw hole fixed on the lip-cheek side, and the other side of the double-retention stent main body is provided with a screw hole fixed on the palatal side; a plurality of planting base tables are arranged in the middle of the double-retention bracket main body; the double-retention stent main body reconstructs a complete jaw bone structure of a patient through scanning data, extracts bone surface contours of the lip-cheek side and the palatal side to obtain a basic stent model, optimizes the layout of an implant abutment in combination with a stress distribution result and screw hole positions of the lip side and the palatal side through three-dimensional finite element analysis, and then adopts a topological optimization method to obtain a complete jaw bone structure of the patient. And the implant stent is manufactured through 3D printing. While the rigidity and durability are guaranteed, the overall structure is lighter, and the number of used screws is smaller, so that the pressure of a patient during wearing is relieved, the service life of the support is remarkably prolonged, and the risk of pressure injury is reduced.

Description

Technical Field

[0001] The present invention relates to a labial, buccal and palatal dual-retention subperiosteal implant bracket and a manufacturing method, and in particular to a labial, buccal and palatal dual-retention subperiosteal implant and a manufacturing method based on 3D finite element analysis optimization design and 3D printing, belonging to the field of oral implantology and medical device design. Background Art

[0002] With the development of modern oral implant technology, the reliance of traditional dental implant technology on bone quantity and quality has limited its application in patients with severe bone deficiency, such as those with severe jaw atrophy, insufficient bone in the maxillary sinus region, or mandibular nerve restriction. Furthermore, elderly patients, individuals with systemic diseases, and cases of bone resorption caused by implant failure also pose challenges to traditional implant technology. To address these issues, subperiosteal implants, by covering the bone surface (subperiosteum) rather than implanting into the bone, circumvent the strict bone quantity requirements and provide a safer, minimally invasive, and widely adaptable restorative solution. Subperiosteal implants offer significant advantages, including personalized design to adapt to the patient's jaw anatomy, no need for bone augmentation surgery, minimal surgical trauma, and rapid recovery. Furthermore, their multi-point retention design and advanced biomaterial surface treatment further enhance mechanical stability and biocompatibility. Compared to traditional implant technology, subperiosteal implants significantly improve the patient experience and shorten the treatment cycle, providing an important treatment option for patients who are unable to undergo traditional implants and promoting innovation and development in oral implant technology.

[0003] However, current subperiosteal implants suffer from insufficient bone mass and unstable unilateral retention, resulting in poor adaptability, insufficient retention, and postoperative complications. Because occlusal forces vary at different locations, implants need to be designed with structures adapted to these forces at different locations. Accurately simulating the stress distribution of implants under varying occlusal forces during the design phase, as well as accurately assessing the stress conditions in the contact area between subperiosteal implants and the bone surface and soft tissue, remain current challenges. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: how to make the stress distribution of the oral implant bracket uniform during use, solve the lightweight problem while ensuring rigidity, and avoid the problems of insufficient bone volume and unilateral retention instability.

[0005] In order to solve the above technical problems, the technical solution of the present invention is to provide a double-retained subperiosteal implant bracket on the labial and buccal sides and the palatal side, characterized in that it includes a double-retained bracket body, one side of the double-retained bracket body is provided with a screw hole fixed to the labial and buccal side, the other side of the double-retained bracket body is provided with a screw hole fixed to the palatal side, and the middle part of the double-retained bracket body is provided with multiple implant bases;

[0006] The main body of the double-retaining bracket reconstructs the patient's complete jaw structure through scanning data, extracts the labial, buccal and palatal bone surface contours, and simultaneously designs the bilateral connecting plate contours in the three-dimensional model to obtain the basic bracket model. Then, through three-dimensional finite element analysis, the layout of the implant base is combined with the stress distribution results and the screw hole positions on the labial and palatal sides to optimize. Then, the topological optimization method is used to obtain the optimal implant bracket shape, and the implant bracket is manufactured by 3D printing.

[0007] Preferably, the main body of the double-retention bracket includes a labial and buccal connecting plate and a palatal connector that are integrally connected, and a plurality of implant bases are provided between the labial and buccal connecting plate and the palatal connector; the labial and buccal connecting plate is a fitting structure designed according to the residual bone surface morphology of the patient's labial and buccal sides, and the edge of the labial and buccal connecting plate is provided with a plurality of screw holes for easy fixation to the labial and buccal bone surface; the palatal connector is a three-dimensional fitting structure constructed along the patient's palatal process and adjacent areas, and the edge of the palatal connector is provided with a plurality of screw holes for auxiliary palatal retention.

[0008] Preferably, there is only one screw hole on the palatal connector, which is the third screw hole; there are two screw holes on the labial and buccal connecting plate, one is a plurality of first screw holes located close to the nasal cavity, and the other is a plurality of second screw holes located at the lower end of the cheek; two support rods extend from both ends of the labial and buccal connecting plate, namely the first support rod and the second support rod, and the plurality of first screw holes are provided on the end of the second support rod and are arranged in sequence along the length direction of the second support rod, and the plurality of second screw holes are provided on the end of the first support rod and are arranged in sequence along the length direction of the first support rod.

[0009] Preferably, the steps of obtaining the basic scaffold model are as follows:

[0010] The patient's complete jaw structure was reconstructed based on CBCT scanning data, the labial, buccal and palatal bone contours were extracted, and the contours of the bilateral connecting plates were simultaneously designed in the three-dimensional model, laying the foundation for the design of the double-retained bracket body. The anatomical characteristics and restoration requirements were comprehensively considered to design the distribution structure of the double-retained bracket body and multiple implant abutments, and the screw hole positions on the labial and palatal sides were rationally planned to achieve balanced retention and stable support for the implants, thus obtaining a model structure of the basic bracket that fits the human maxillary bone.

[0011] Preferably, the three-dimensional finite element analysis is as follows: applying multi-directional simulated bite loads, analyzing stress concentration in different areas, optimizing the plate thickness and connection form according to the force line direction, and ensuring uniform force. The specific steps are as follows:

[0012] Step 1: Import the model structure of the basic bracket into the finite element platform to obtain the oral implant bracket model; perform finite element meshing on the oral implant bracket model;

[0013] Step 2: Perform physical field modeling on the oral implant bracket model and assign material properties to the implant and maxillary bone;

[0014] Step 3: Obtain the pressure exerted on the oral implant bracket during chewing in the oral cavity;

[0015] Step 4: Determine the boundary conditions and loads of the system: Since the upper surface of the human maxillary bone is completely fixed, the vertical load is directly applied to the oral implant bracket.

[0016] Step 5: Analyze the simulation results: including pressure distribution, Mises stress distribution and displacement distribution.

[0017] Preferably, in step 1, when dividing the finite element mesh, small mesh units are used in the contact area between the screw and the human maxillary bone and the oral implant bracket on the oral implant bracket model, and large mesh units are used in the remaining areas on the oral implant bracket model, so as to achieve a balance between accuracy and computational efficiency.

[0018] Preferably, the topology optimization method is used to obtain the optimal implant support shape with the goal of minimizing and maximizing Mises stress; the specific method is:

[0019] S31, initializing design variables;

[0020] S32, establishing an objective function, wherein the objective function is to minimize the maximum Mises stress of the oral implant bracket;

[0021] S33. Use numerical methods to calculate the sensitivity of objective functions and constraints to design variables;

[0022] S34, updating the design variables according to the sensitivity;

[0023] S35. updating the material properties of the finite element model according to the updated design variables;

[0024] S36. Determine the stopping condition and check whether the current number of iterations or volume fraction meets the stopping condition; if so, stop the iteration and output the current optimal design variable distribution, that is, the optimal implant shape; otherwise, return to step S33 and continue iteration.

[0025] Preferably, in step S31, the design variable is the unit density, which represents the relative content of the material in each finite element unit; in step S35, the SIMP interpolation model is used to associate the unit density with the material elastic modulus, and the updated finite element model is solved to calculate the design response of the stress and displacement of the implant.

[0026] Preferably, the surface of the double-retaining stent body on the bone contact side is a rough mesh structure; and the surface of the double-retaining stent body on the soft tissue contact side is a highly polished structure.

[0027] A method for manufacturing a labial, buccal, and palatal dual-retention subperiosteal implant scaffold, characterized by comprising the following steps:

[0028] Step 1: 3D reconstruction and structural sketch design

[0029] The patient's complete jaw structure was reconstructed based on CBCT scan data, the labial, buccal, and palatal bone contours were extracted, and the contours of the bilateral connection plates were simultaneously designed in the 3D model, laying the foundation for the design of the dual-retaining bracket.

[0030] Step 2: Implant layout and connection structure construction

[0031] Based on the anatomical characteristics and restoration requirements, the distribution structure of the dual-retention bracket body and multiple implant abutments was designed, and the screw hole positions on the labial and palatal sides were rationally planned to achieve balanced retention and stable support for the implants, resulting in a model structure of the basic bracket that fits the human maxillary bone.

[0032] Step 3: 3D finite element analysis and topology optimization

[0033] The model structure of the foundation bracket was imported into the finite element platform, and multi-directional simulated bite loads were applied to analyze the stress concentration in different areas. The plate thickness and connection form were optimized according to the force line direction to ensure uniform force distribution and high overall safety.

[0034] Step 4: Printing and Precision Machining

[0035] After completing the optimized design of the oral implant bracket, the oral implant bracket is prepared through 3D printing technology. High-performance titanium alloy materials are selected, and the bracket is manufactured using SLM or EBM metal 3D printing technology. After printing is completed, CNC precision machining technology is used to trim the key connection surfaces to improve the structural fit and stability.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. Provide multi-directional mechanical support to avoid eccentric loading or rotational instability;

[0038] 2. Ensure accurate positioning of the restoration and strong adaptability;

[0039] 3. Reduce bone stress concentration and improve long-term biomechanical stability;

[0040] 4. There is sufficient space for postoperative restoration to meet various upper restoration needs (bridge, telescopic crown, etc.).

[0041] Subperiosteal implant designs based on 3D finite element analysis demonstrate superior mechanical optimization and structural adaptability compared to traditional approaches. Through digital modeling and occlusal mechanics simulation, the stress distribution of the implant under varying occlusal forces can be accurately simulated during the design phase, allowing targeted optimization of critical stress-bearing areas and effectively improving the mechanical stability and long-term lifespan of the restoration. Finite element analysis also accurately assesses the stress conditions in the subperiosteal implant's contact areas with the bone surface and soft tissue, providing a scientific basis for the implant's biomechanical performance. Modeling based on patient CT data, combined with finite element analysis optimization, and then directly 3D printing allows the implant's morphology to closely match the individual's bone anatomy, avoiding the large errors and poor fit associated with traditional manual shaping. This technology not only simulates the fatigue performance of the implant over long-term use and predicts potential mechanical risks, but also effectively reduces the incidence of localized mechanical stress concentrations and biocompatibility issues. The overall design better meets the individual patient's needs, significantly improving postoperative comfort and clinical success rates. This type of technology-driven innovation provides solid support for the development of subperiosteal implants, demonstrating enhanced performance advantages and broad clinical application prospects.

[0042] The present invention can realize customized design of oral implant brackets, construct a three-dimensional model of the oral implant bracket based on the obtained human maxillary model, use finite element simulation technology to simulate the implant, obtain the Mises stress distribution, and then based on the topology optimization method, with the purpose of reducing the maximum Mises stress, make the Mises stress distribution more uniform. While ensuring rigidity and durability, the overall structure is lighter and uses fewer screws, which can better adapt to the patient's oral physiological condition, thereby reducing the pressure on the patient when wearing it, significantly improving the service life of the bracket, and reducing the risk of pressure damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of a labial, buccal and palatal dual-retention subperiosteal implant scaffold;

[0044] Figure 2 Schematic diagram of finite element meshing for the human maxillary model;

[0045] Figure 3 Comparison diagram of Mises stress before and after stent optimization; (a) is the Mises stress diagram before stent optimization; (b) is the Mises stress diagram after stent optimization;

[0046] Figure 4 Schematic diagram of the installation and use of a double-retained subperiosteal implant bracket on the labial, buccal and palatal sides.

[0047] in:

[0048] 1 is the main body of the double-retaining bracket; 2 is the implant base; 3 is the screw;

[0049] 11 is the first support rod; 12 is the palatal edge; 13 is the third screw hole; 14 is the first screw hole; 15 is the second support rod; 16 is the second screw hole. DETAILED DESCRIPTION

[0050] To make the present invention more clearly understood, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0051] The present invention provides a double-retained subperiosteal implant bracket for the buccal and palatal sides based on three-dimensional finite element analysis and 3D printing technology. Figure 1 As shown, it includes a double-retaining bracket body 1, one side of the double-retaining bracket body 1 is provided with a screw hole for fixing to the labial and buccal side, the other side of the double-retaining bracket body 1 is provided with a screw hole for fixing to the palatal side, and a plurality of implant bases 2 are provided in the middle of the double-retaining bracket body 1;

[0052] The main body 1 of the double-retention bracket includes a labial and buccal connecting plate and a palatal connector that are integrally formed and connected, and a plurality of implant bases 2 are arranged between the labial and buccal connecting plate and the palatal connector; the labial and buccal connecting plate is a fitting structure designed according to the residual bone surface morphology of the patient's labial and buccal sides, and the edge of the labial and buccal connecting plate is provided with a plurality of screw holes for easy fixation to the labial and buccal bone surface; the palatal connector is a three-dimensional fitting structure constructed along the patient's palatal process and adjacent areas, and the edge of the palatal connector is provided with a plurality of screw holes for auxiliary palatal retention.

[0053] There is only one screw hole on the palatal connector, which is the third screw hole 13; there are two screw holes on the labial and buccal connecting plate, one is a plurality of first screw holes 14 located near the nasal cavity, and the other is a plurality of second screw holes 16 located at the lower end of the cheek; two support rods extend from both ends of the labial and buccal connecting plate, namely the first support rod 11 and the second support rod 15, and the plurality of first screw holes 14 are provided on the end of the second support rod 15 and are arranged in sequence along the length direction of the second support rod 15, and the plurality of second screw holes 16 are provided on the end of the first support rod 11 and are arranged in sequence along the length direction of the first support rod 11.

[0054] The double-retained bracket main body 1 reconstructs the patient's complete three-dimensional jaw structure through CBCT scanning data, extracts the labial, buccal and palatal bone surface contours, and simultaneously designs the bilateral connecting plate contours in the three-dimensional model to obtain the basic bracket model. Then, the occlusal force and multi-directional stress distribution are simulated through three-dimensional finite element analysis. The structure of the double-retained bracket main body 1, the layout of the implant base 2, combined with the stress distribution results and the screw hole positions on the labial and palatal sides are optimized to achieve the best match in terms of mechanical properties, bone surface fit and postoperative stability. Then, the topological optimization method is used to obtain the optimal implant bracket shape, and the implant bracket is manufactured by 3D printing.

[0055] The labial and buccal connecting plate is designed to fit the patient's residual buccal bone surface. Multiple screw holes are located along the edge of the bracket to facilitate intraoperative fixation to the buccal bone surface. The labial and buccal bracket (i.e., the labial and buccal connecting plate) is inserted 0.5–1 mm into the bone to enhance initial stability and facilitate new bone wrapping.

[0056] Palatal connector: A three-dimensional fitting structure is constructed along the palatal process and adjacent areas. Screw holes are also provided to provide palatal auxiliary retention. The palatal portion (i.e., the palatal connector) extends approximately 0.5–1 mm into the bone to enhance shear resistance and overall support.

[0057] Implant Abutments 2: Several implant abutments 2 are placed between the labial and buccal connectors and the palatal connector. They penetrate the soft tissue, emerge from the oral cavity, and serve as connections to the upper restoration. The layout of the implant abutments 2 is optimized based on stress distribution results to ensure balanced force distribution across each abutment under occlusal load, avoiding stress concentration.

[0058] Surface structure treatment: A rough mesh structure is provided on the surface of the double-retaining stent body 1 on the bone contact side, which is beneficial to bone integration and long-term stability; the double-retaining stent body 1 on the soft tissue contact side is highly polished to reduce the risk of soft tissue irritation and exposure.

[0059] The specific optimized manufacturing method of a labial, buccal and palatal dual-retention subperiosteal implant scaffold is as follows:

[0060] Step 1: 3D reconstruction and structural sketch design

[0061] The patient's complete jaw structure was reconstructed based on CBCT scan data, the labial, buccal, and palatal bone contours were extracted, and the contours of the bilateral connection plates were simultaneously designed in the 3D model, laying the foundation for the design of the dual-retaining bracket body 1.

[0062] Step 2: Implant layout and connection structure construction

[0063] Based on the anatomical characteristics and restoration requirements, the distribution structure of the double-retained bracket body 1 and multiple implant abutments 2 was designed, and the screw hole positions on the labial and palatal sides were rationally planned to achieve balanced retention and stable support for the implants, resulting in a model structure of the basic bracket that fits the human maxillary bone.

[0064] Step 3: Finite element simulation (3D finite element analysis optimization) and structural parameter optimization (using topology optimization method)

[0065] The model structure of the foundation bracket is imported into the finite element platform, and multi-directional simulated bite loads are applied to analyze the stress concentration in different areas. The plate thickness and connection form are optimized according to the direction of the force line to ensure uniform force and high overall safety.

[0066] Three-dimensional finite element analysis uses finite element simulation technology to simulate the oral implant bracket, simulate and analyze the constructed oral implant bracket model, and obtain its Mises stress distribution. The specific steps are as follows:

[0067] S21. Import the model structure of the basic bracket into the finite element platform to obtain the oral implant bracket model; the three-dimensional model of the oral implant bracket can be created using a computer-aided design tool (nTop, New York, USA). Perform finite element meshing on the oral implant bracket model: the smaller the unit of the finite element mesh, the higher the accuracy of the calculation, but the greater the amount of calculation. In order to strike a balance between accuracy and computational efficiency, smaller mesh units can be used in the contact area between the screw and the human maxillary bone and bracket as needed. The schematic diagram of finite element meshing is shown in the figure below. Figure 2 As shown;

[0068] S22. Perform physical field modeling on the oral implant scaffold model: assign material properties to the implant and maxillary bone; the material properties of the oral implant scaffold need to consider its mechanical properties, such as elastic modulus and Poisson's ratio; the material properties of the human maxillary bone model refer to the mechanical properties of human cortical bone.

[0069] S23. Obtain the pressure exerted on the oral implant bracket during chewing in the mouth by reviewing literature and conducting clinical research.

[0070] S24. Determine the boundary conditions and loads of the system: the upper surface of the human maxillary bone is completely fixed, and a vertical load is directly applied to the oral implant bracket model.

[0071] S25. Analyze simulation results: including pressure distribution, Mises stress distribution and displacement distribution.

[0072] The calculation formula of Mises stress is:

[0073]

[0074] Among them, σ1, σ2, and σ3 are three principal stresses. The principal stresses of each unit are calculated by finite element method, and then the Mises stress of each unit is obtained as the basic data of the design response.

[0075] The above simulation process using finite element analysis (FEA) is performed by using specialized finite element analysis software Abaqus.

[0076] S3. Use topology optimization to minimize the maximum Mises stress (Mises stress is a yield criterion, and its value is usually called equivalent stress) to obtain the optimal implant scaffold shape. The specific method is as follows:

[0077] S31, initializing design variables. In this embodiment, the design variable is unit density;

[0078] Element density is a core design variable that represents the relative amount of material in each finite element. Its value range is usually from 0 (no material) to 1 (solid material). In this example, the density of all elements in the design domain is initially set to 0.5 (indicating medium density).

[0079] S32. Establish an objective function. The objective function is typically to minimize or maximize a scalar quantity extracted from the design response. In this embodiment, the objective function is to minimize the maximum Mises stress of the implant.

[0080] The objective function can be expressed as

[0081] J=min(max(σ vM,i ))

[0082] Among them, J is the objective function, σ vM,i represents the Mises stress of the ith element, max(σ vM,i ) represents the maximum value of the Mises stress of all elements, and the optimization process aims to make this maximum value as small as possible by changing the design variables.

[0083] S33. Calculate sensitivity: Use numerical methods to calculate the sensitivity of the objective function and constraints to the design variables;

[0084] Sensitivity analysis is to calculate the derivatives of the objective function and constraints with respect to the unit density, which is used to guide the updating direction of the design variables. The calculation formula of the objective function sensitivity is:

[0085]

[0086] in, represents the sensitivity of Mises stress to element density, x_i represents element density, represents the principal stress components (j = 1, 2, 3);

[0087] S34: Update the design variables according to the sensitivity calculated in step S33. This is achieved through the optimization criterion method. The specific formula of the optimization criterion method is:

[0088]

[0089] in, represents the density of unit i at the k+1th iteration, c i represents the sensitivity of the objective function to the density of unit i, λ represents the Lagrange multiplier, m represents the maximum change in each iteration, x min and x maxIndicates the lower and upper limits of density, usually 0.001 and 1;

[0090] S35. Update the material properties of the finite element model based on the updated cell density value. Use the SIMP (Solid Isotropic Material with Penalization) interpolation model to relate the cell density to the material elastic modulus, solve the updated finite element model, and calculate the design response of the implant, such as stress and displacement;

[0091] The SIMP interpolation formula is as follows:

[0092]

[0093] Among them, E0 is the elastic modulus of the solid material, E min is the elastic modulus of the cavity area (usually a very small value, such as E min =10 -9 E0), p is a penalty factor (generally p≥3), which is used to penalize the intermediate density units and promote the design to develop towards 0-1 discretization.

[0094] S36: Determine the stopping condition and check whether the current number of iterations or volume fraction meets the stopping condition. If so, stop the iteration and output the current optimal cell density distribution, i.e., the optimal implant shape. Otherwise, return to step S33 and continue the iteration.

[0095] The stopping condition can be expressed as

[0096]

[0097] Among them, V current is the implant volume of the current iteration step, V initial is the volume of the initial implant, f is the designed volume fraction, n is the current iteration number, N max is the maximum number of iterations, and ∨ represents a logical OR operation.

[0098] With material design strength as the goal, geometric models of implants with varying dimensions (e.g., implant thickness, typically the thickness of the rod near the implant abutment 2) and configurations (changing the internal structure while the implant outline is fixed) are established. Finite element analysis is then used to determine the size range and different structural configurations that meet the material design strength target. Alternatively, if the implant outline and internal structure are fixed, only geometric parameters such as thickness need to be varied when performing multiple finite element analyses.

[0099] Step 4: Printing and Precision Machining

[0100] After completing the optimized design of the oral implant bracket, the oral implant bracket can be prepared through 3D printing technology. High-performance titanium alloy materials are selected, and the bracket is manufactured using SLM or EBM metal 3D printing technology. After printing is completed, CNC precision machining technology is used to trim the key connection surfaces to improve the structural fit and stability.

[0101] The specific steps are as follows:

[0102] Generate 3D printing files: First, export the optimized oral implant framework design from the finite element simulation software and convert it into the STL file format suitable for 3D printing.

[0103] Prepare a 3D printer: Based on the design requirements and usage characteristics of the oral implant scaffold, select an appropriate 3D printer and choose the appropriate printing material. Since the oral implant scaffold needs to be implanted in the human oral environment, the material must be safe, non-toxic, comfortable, and possess sufficient strength and elasticity. Possible materials include plastics (such as PLA and ABS), elastomers (such as TPU), or specialized biomedical 3D printing materials.

[0104] Set 3D printing parameters: Based on the performance of the selected 3D printer and the characteristics of the printing material, reasonably set the 3D printing parameters, mainly including but not limited to parameters such as printing speed, layer thickness, filling density, printing temperature, etc., to ensure printing quality.

[0105] Start 3D printing: Load the generated 3D print file into the 3D printer and start the printing process after confirming that it is correct. During the printing process, the 3D printer will add printing material layer by layer according to the design of the 3D model, and finally form a three-dimensional oral implant framework.

[0106] Post-processing: After printing, a series of post-processing operations may be required to ensure the safety and comfort of the oral implant scaffold. These include removing support structures used during printing, smoothing the surface, and performing rigorous disinfection. Surface treatment includes roughening (sandblasting, acid etching, etc.) the bone-contacting surface of the scaffold to promote osseointegration. The soft-tissue contacting surface of the scaffold is highly polished to reduce the risk of soft-tissue exposure.

[0107] Step 5: Surgical operation and bilateral fixation

[0108] Stent sterilization and fit evaluation were completed before the operation. During the operation, flaps were opened from the labial and buccal sides and the palatal sides respectively, and the stent was implanted into the mandibular surface according to the designed position. Multiple screws were used to simultaneously fix the two sides, and then the wound was sutured.

[0109] Step 6: Restoration Phase Management and Long-term Follow-up

[0110] After surgery, a temporary restoration is placed to maintain function and morphology. After bone integration is complete (approximately 4 to 6 months), a permanent restoration is installed, and regular follow-up is performed to ensure the restoration effect and long-term stability of the implant.

[0111] The invention has achieved a breakthrough in optimizing 3D-printed stents. Using a 70% volume fraction as the core constraint, the invention's implementation method successfully achieved a significant improvement in stent performance.

[0112] Before the adoption of the present invention, the maximum stress the stent could withstand under the same working conditions was 1,526 MPa, which severely impacted the stent's service life and brought potential risks to clinical applications. However, after the adoption of the present invention, the maximum stress was significantly reduced to 591 MPa, a decrease of 61.3%. Figure 3 As shown, it is far lower than the tensile strength of titanium alloy.

[0113] The stent of the present invention has achieved a qualitative leap in mechanical properties while maintaining the original load-bearing capacity, which not only greatly enhances the structural stability and durability of the stent, but also provides more reliable protection for patient safety.

Claims

1. A double-retained subperiosteal implant bracket on the lip, buccal and palatal sides, characterized in that: The double-retaining bracket body (1) comprises a double-retaining bracket body (1), wherein one side of the double-retaining bracket body (1) is provided with a screw hole for fixing to the labial and buccal side, the other side of the double-retaining bracket body (1) is provided with a screw hole for fixing to the palatal side, and a plurality of implant bases (2) are provided in the middle of the double-retaining bracket body (1); The main body of the double-retaining bracket (1) reconstructs the patient's complete jaw structure through scanning data, extracts the labial and buccal and palatal bone surface contours, and simultaneously designs the bilateral connecting plate contours in the three-dimensional model to obtain the basic bracket model. Then, through three-dimensional finite element analysis, the layout of the implant base (2) is combined with the stress distribution results and the screw hole positions on the labial and palatal sides to optimize. Then, the topological optimization method is used to obtain the optimal implant bracket shape, and the implant bracket is manufactured by 3D printing.

2. The labial, buccal and palatal dual-retention subperiosteal implant scaffold according to claim 1, characterized in that: The double-retention bracket body (1) includes an integrally formed labial and buccal connecting plate and a palatal connecting body, and a plurality of implant bases (2) are provided between the labial and buccal connecting plate and the palatal connecting body; the labial and buccal connecting plate is a fitting structure designed according to the residual buccal bone surface morphology of the patient, and the edge of the labial and buccal connecting plate is provided with a plurality of screw holes for easy fixation to the labial and buccal bone surface; the palatal connecting body is a three-dimensional fitting structure constructed along the patient's palatal process and adjacent areas, and the edge of the palatal connecting body is provided with a plurality of screw holes for auxiliary palatal retention.

3. The labial, buccal and palatal dual-retention subperiosteal implant scaffold according to claim 1, characterized in that: There is only one screw hole on the palatal connector, which is the third screw hole (13); there are two screw holes on the labial and buccal connecting plate, one is a plurality of first screw holes (14) located near the nasal cavity, and the other is a plurality of second screw holes (16) located at the lower end of the cheek; two support rods extend from both ends of the labial and buccal connecting plate, namely the first support rod (11) and the second support rod (15), the plurality of first screw holes (14) are provided on the end of the second support rod (15), and are arranged in sequence along the length direction of the second support rod (15), and the plurality of second screw holes (16) are provided on the end of the first support rod (11), and are arranged in sequence along the length direction of the first support rod (11).

4. The labial, buccal and palatal dual-retention subperiosteal implant scaffold according to claim 1, characterized in that: The steps for obtaining the basic support model are as follows: The patient's complete jaw structure was reconstructed based on CBCT scan data, the labial and buccal and palatal bone surface contours were extracted, and the bilateral connection plate contours were simultaneously designed in the 3D model, laying the foundation for the design of the dual-retaining bracket body (1); Based on the anatomical characteristics and restoration requirements, the distribution structure of the double-retention bracket main body (1) and multiple implant bases (2) is designed, and the screw hole positions on the labial and palatal sides are rationally planned to achieve balanced retention and stable support for the implants, and obtain a model structure of the basic bracket that fits the human maxillary bone.

5. The labial, buccal and palatal dual-retention subperiosteal implant scaffold according to claim 1, characterized in that: The three-dimensional finite element analysis involves applying multi-directional simulated bite loads, analyzing stress concentration in different areas, and optimizing the plate thickness and connection configuration based on the force line direction to ensure uniform stress distribution. The specific steps are as follows: Step 1: Import the model structure of the basic bracket into the finite element platform to obtain the oral implant bracket model; perform finite element meshing on the oral implant bracket model; Step 2: Perform physical field modeling on the oral implant bracket model and assign material properties to the implant and maxillary bone; Step 3: Obtain the pressure exerted on the oral implant bracket during chewing in the oral cavity; Step 4: Determine the boundary conditions and loads of the system: Since the upper surface of the human maxillary bone is completely fixed, the vertical load is directly applied to the oral implant bracket. Step 5: Analyze the simulation results: including pressure distribution, Mises stress distribution and displacement distribution.

6. The labial, buccal and palatal dual-retention subperiosteal implant scaffold according to claim 5, characterized in that: In step 1, when dividing the finite element mesh, small mesh units are used in the contact area between the screw and the human maxillary bone and the oral implant bracket on the oral implant bracket model, and large mesh units are used in the remaining areas on the oral implant bracket model, so as to achieve a balance between accuracy and computational efficiency.

7. The labial, buccal and palatal dual-retention subperiosteal implant scaffold according to claim 1, characterized in that: The topology optimization method is used to obtain the optimal implant scaffold shape with the goal of minimizing and maximizing Mises stress; the specific method is as follows: S31, initializing design variables; S32, establishing an objective function, wherein the objective function is to minimize the maximum Mises stress of the oral implant bracket; S33. Use numerical methods to calculate the sensitivity of objective functions and constraints to design variables; S34, updating the design variables according to the sensitivity; S35. updating the material properties of the finite element model according to the updated design variables; S36. Determine the stopping condition and check whether the current number of iterations or volume fraction meets the stopping condition; if so, stop the iteration and output the current optimal design variable distribution, that is, the optimal implant shape; otherwise, return to step S33 and continue iteration.

8. The labial, buccal and palatal dual-retention subperiosteal implant scaffold according to claim 7, characterized in that: In step S31, the design variable is the unit density, which represents the relative content of the material in each finite element unit; in step S35, the SIMP interpolation model is used to associate the unit density with the material elastic modulus, and the updated finite element model is solved to calculate the design response of the stress and displacement of the implant.

9. The labial, buccal and palatal dual-retention subperiosteal implant scaffold according to claim 1, characterized in that: The surface of the double-retention bracket main body (1) on the bone contact side is a rough mesh structure; the surface of the double-retention bracket main body (1) on the soft tissue contact side is a highly polished structure.

10. A method for manufacturing a labial, buccal and palatal dual-retention subperiosteal implant scaffold according to claim 1, characterized in that: The following steps are involved: Step 1: 3D reconstruction and structural sketch design The patient's complete jaw structure was reconstructed based on CBCT scan data, the labial and buccal and palatal bone surface contours were extracted, and the bilateral connection plate contours were simultaneously designed in the 3D model, laying the foundation for the design of the dual-retaining bracket body (1); Step 2: Implant layout and connection structure construction The distribution structure of the double-retention bracket main body (1) and multiple implant bases (2) is designed based on the comprehensive anatomical characteristics and repair requirements, and the screw hole positions on the labial and palatal sides are rationally planned to achieve balanced retention and stable support for the implants, thereby obtaining a model structure of the basic bracket that fits the human maxillary bone; Step 3: 3D finite element analysis and topology optimization The model structure of the foundation bracket was imported into the finite element platform, and multi-directional simulated bite loads were applied to analyze the stress concentration in different areas. The plate thickness and connection form were optimized according to the force line direction to ensure uniform force distribution and high overall safety. Step 4: Printing and Precision Machining After completing the optimized design of the oral implant bracket, the oral implant bracket is prepared by 3D printing technology. High-performance titanium alloy materials are selected and the bracket is manufactured using SLM or EBM metal 3D printing technology; After printing is completed, CNC precision machining technology is used to trim key connection surfaces to improve structural fit and stability.

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