Method for constructing maxillary sinus lift model by inverse three-dimensional finite element and hydraulic lifting method

Abstract

The application provides a method for constructing a maxillary sinus lifting model by using a reverse three-dimensional finite element and hydraulic lifting method, and the method comprises the following steps: collecting a maxillary bone CBCT image, extracting a maxillary sinus three-dimensional model contour, and performing three-dimensional reverse reconstruction to generate three-dimensional models of cortical bone, cancellous bone and mucosa. Subsequently, a maxillary sinus lifting channel model is established, assembled into a complete maxillary sinus three-dimensional model, and material parameters and contact relationships are given, a tetrahedral mesh is divided to obtain a finite element model, and then the hydraulic lifting loading is simulated and iteratively solved, and finally a maxillary sinus lifting model is obtained. Compared with the traditional impact method, the method has lower operation difficulty and risk, is safer, and solves the problems of nonlinear large deformation and complex contact behavior, thereby improving the accuracy and stability of the simulation results.

Description

Technical Field

[0001] This invention relates to the field of maxillary sinus lift technology, and in particular to a method for constructing a maxillary sinus lift model using inverse three-dimensional finite element method and hydraulic lifting method. Background Technology

[0002] In the field of oral medicine, maxillary sinus lift is used to increase the bone height in the maxillary posterior region to facilitate implant placement. Traditional maxillary sinus lift techniques primarily employ the impact method, which uses tools such as impactors to directly apply pressure to the maxillary sinus floor mucosa or bone, lifting the sinus floor mucosa indirectly or directly. However, this method has several significant drawbacks: First, the impact method requires the operator to constantly adjust the force and rhythm of the impacts based on feel, demanding a high level of skill and making it difficult to precisely control the height and force of the lift, thus increasing the risk and uncertainty of the surgery. Furthermore, the application of the impact method becomes even more difficult when the maxillary sinus floor has complex morphologies such as septa or slopes, further increasing the surgical risk.

[0003] With the development of computer technology, the finite element analysis (FEA) method has been widely used in oral biomechanics research. By constructing a three-dimensional finite element model of the maxillary sinus, the process of maxillary sinus lift surgery can be simulated, and the biomechanical effects of different methods on the maxillary sinus mucosa can be analyzed. However, the results are not only related to the accuracy of the finite element model, but also closely related to the structural study of the material properties of the model and the setting of the model boundary conditions. Although in vitro experiments have provided some understanding of the mechanical properties and deformation characteristics of the maxillary sinus mucosa, the maxillary sinus mucosa is a complex soft tissue material with large deformation and nonlinearity, making finite element modeling and calculation methods more complex. The main reasons are as follows: First, hyperelastic materials have a nonlinear stress-strain relationship, and their behavior is difficult to describe with a simple linear model. This requires the use of more complex material models to accurately capture the material behavior, such as the Mooney-Rivlin, Yeoh, or Arruda-Boyce models; Second, hyperelastic membrane materials may undergo large deformations during loading, which not only places demands on the material model, but also poses challenges to the numerical methods of the solver. Large deformation problems involve updating material configurations and handling nonlinear geometry, requiring specific numerical algorithms to ensure computational accuracy and stability. Third, handling contact problems becomes particularly complex when the membrane material is in contact with other objects or folds itself. Contact analysis needs to consider friction, adhesion, and other behaviors between contact surfaces, increasing the nonlinearity of the model and the difficulty of solving. Fourth, boundary conditions and loading implementation: For membrane materials, boundary conditions and loading methods may be unique, such as the application of prestress and boundary constraints, requiring special attention during modeling and loading to ensure analytical accuracy. Fifth, due to the nonlinear problems and large deformation handling mentioned above, three-dimensional finite element analysis of hyperelastic membrane materials typically requires high computational resources, including long computation times and large memory requirements, which is especially evident for large-scale problems or those requiring fine meshing.

[0004] Therefore, existing techniques for constructing maxillary sinus lift models using the impact method suffer from drawbacks such as high operational difficulty, high risk, and inaccurate simulation results. Furthermore, FEA (Features-Enhanced Anatomy) also faces challenges in constructing maxillary sinus lift models, including complex material models, time-consuming calculations, and unstable results. To address these issues, a more accurate, reliable, and easy-to-operate method for constructing maxillary sinus lift models is needed. Summary of the Invention

[0005] In view of the above problems, the present invention is proposed to provide a method for constructing a maxillary sinus elevation model by reverse three-dimensional finite element method and hydraulic lifting method to overcome or at least partially solve the above problems, a corresponding apparatus for constructing a maxillary sinus elevation model by reverse three-dimensional finite element method and hydraulic lifting method, an electronic device, and a computer-readable medium.

[0006] This invention discloses a method for constructing a maxillary sinus lift model using inverse three-dimensional finite element method and hydraulic lifting method, the method comprising:

[0007] Acquire CBCT images of the maxilla and extract the three-dimensional model contour of the maxillary sinus from the CBCT images of the maxilla;

[0008] The contour of the maxillary sinus three-dimensional model is reconstructed in three dimensions to generate a three-dimensional model of cortical bone, a three-dimensional model of cancellous bone, and a three-dimensional model of mucosa. The three-dimensional models of cortical bone, cancellous bone, and mucosa are then repaired by feature recognition and surface diagnosis to repair any flawed surfaces.

[0009] A three-dimensional model of the maxillary sinus elevation channel was established, and the three-dimensional models of cortical bone, cancellous bone, mucosa, and maxillary sinus elevation channel were assembled into a three-dimensional model of the maxillary sinus.

[0010] The corresponding material parameters and contact relationships are assigned to the three-dimensional cortical bone model, cancellous bone model, mucosa model, and maxillary sinus elevation channel model of the three-dimensional model of the maxillary sinus, respectively. The three-dimensional model of the maxillary sinus is then divided using a tetrahedral mesh to obtain a three-dimensional finite element model of the maxillary sinus.

[0011] A loading surface is formed on the mucosal surface of the three-dimensional finite element model of the maxillary sinus by projecting the channel through it. The loading surface is then subjected to load by simulating hydraulic lifting. Meanwhile, the Mooney-Rivlin model and the updated Lagrange method are used for iterative solution in the finite element analysis until the calculation converges, thus obtaining the maxillary sinus lifting model.

[0012] Optionally, the mucosa is set to the C10 and C01 parameters of Hyperelastic; the cortical bone and cancellous bone are in bonded contact, and the cortical bone and mucosa are in frictionless contact; when simulating different degrees of mucosal separation, the unseparated mucosal area and the corresponding maxillary bone area are treated as having shared nodes, while the separated mucosal area and the corresponding maxillary bone area are treated as having no contact and no shared nodes.

[0013] Optionally, the loading method is a force load; the force load mode is a quasi-static loading mode starting from 0 kPa and with a rate of 0.1 mm / s; the direction in which the liquid applies uniform pressure to the loading surface is vertical and lateral.

[0014] Optionally, the three-dimensional model of the maxillary sinus elevation channel is a cylindrical hole with a diameter of 4 mm.

[0015] Optionally, in the initial stage of lifting, the stress concentration point of the maxillary sinus mucosa is in the center of the force application point. As the lifting height increases, the stress concentration point spreads from the center to the surrounding areas.

[0016] Optionally, the contour of the maxillary sinus three-dimensional model is reconstructed in three dimensions to generate a three-dimensional model of cortical bone, a three-dimensional model of cancellous bone, and a three-dimensional model of mucosa, including:

[0017] The contour of the three-dimensional model of the maxillary sinus is finely segmented to distinguish the cortical bone region, the cancellous bone region, and the mucosal region;

[0018] The cortical bone region, cancellous bone region, and mucosa region were smoothed, denoised, surface constructed, gridded, and solidified respectively to generate three-dimensional models of cortical bone, cancellous bone, and mucosa; the mucosa thickness was set to 1 mm.

[0019] Optionally, CBCT images of the maxilla are acquired, and the three-dimensional model contour of the maxillary sinus is extracted from the CBCT images of the maxilla, including:

[0020] Scanning the maxilla yields CBCT images of the maxilla;

[0021] The maxillary CBCT image is automatically thresholded based on the gray values ​​of different tissues to initially separate the tissues around the maxillary sinus. Excess parts are erased or missing parts are added, and smoothing is performed to obtain the three-dimensional model outline of the maxillary sinus.

[0022] This invention also discloses an apparatus for constructing a maxillary sinus lift model using inverse three-dimensional finite element method and hydraulic lifting method, the apparatus comprising:

[0023] The maxillary sinus contour extraction module is used to acquire maxillary bone CBCT images and extract the three-dimensional model contour of the maxillary sinus from the maxillary bone CBCT images;

[0024] The three-dimensional reverse reconstruction module is used to perform three-dimensional reverse reconstruction of the contour of the maxillary sinus three-dimensional model, generate a three-dimensional model of cortical bone, a three-dimensional model of cancellous bone, and a three-dimensional model of mucosa, and repair the flawed surfaces of the three-dimensional models of cortical bone, cancellous bone, and mucosa through feature recognition and surface diagnosis.

[0025] The solid assembly module is used to create a three-dimensional model of the maxillary sinus lift channel and assemble the three-dimensional models of cortical bone, cancellous bone, mucosa, and maxillary sinus lift channel into a three-dimensional model of the maxillary sinus.

[0026] The maxillary sinus three-dimensional finite element model construction module is used to assign corresponding material parameters and contact relationships to the three-dimensional cortical bone model, cancellous bone model, mucosa model, and maxillary sinus elevation channel model of the maxillary sinus three-dimensional model, respectively, and to divide the maxillary sinus three-dimensional model using a tetrahedral mesh to obtain the maxillary sinus three-dimensional finite element model.

[0027] The hydraulic lifting and finite element analysis module is used to form a loading surface on the mucosal surface of the three-dimensional finite element model of the maxillary sinus by projecting the channel, and to simulate the hydraulic lifting to apply load to the loading surface. At the same time, the Mooney-Rivlin model and the updated Lagrange method are used for iterative solution in the finite element analysis until the calculation converges to obtain the maxillary sinus lifting model.

[0028] Optionally, the mucosa is set to the C10 and C01 parameters of Hyperelastic; the cortical bone and cancellous bone are in bonded contact, and the cortical bone and mucosa are in frictionless contact; when simulating different degrees of mucosal separation, the unseparated mucosal area and the corresponding maxillary bone area are treated as having shared nodes, while the separated mucosal area and the corresponding maxillary bone area are treated as having no contact and no shared nodes.

[0029] Optionally, the loading method is a force load; the force load mode is a quasi-static loading mode starting from 0 kPa and with a rate of 0.1 mm / s; the direction in which the liquid applies uniform pressure to the loading surface is vertical and lateral.

[0030] Optionally, the three-dimensional model of the maxillary sinus elevation channel is a cylindrical hole with a diameter of 4 mm.

[0031] Optionally, in the initial stage of lifting, the stress concentration point of the maxillary sinus mucosa is in the center of the force application point. As the lifting height increases, the stress concentration point spreads from the center to the surrounding areas.

[0032] Optionally, the three-dimensional reverse reconstruction module includes:

[0033] The region segmentation submodule is used to finely segment the contour of the three-dimensional model of the maxillary sinus, distinguishing the cortical bone region, cancellous bone region and mucosal region.

[0034] The 3D model generation submodule is used to perform smoothing, noise reduction, surface construction, gridding, and solidification operations on the cortical bone region, cancellous bone region, and mucosa region respectively, to generate 3D models of cortical bone, cancellous bone, and mucosa; the mucosa thickness is set to 1mm.

[0035] Optionally, the maxillary sinus contour extraction module includes:

[0036] The maxillary CBCT image acquisition submodule is used to scan the maxilla to obtain maxillary CBCT images;

[0037] The maxillary sinus contour extraction submodule is used to automatically threshold the maxillary bone CBCT image according to the gray values ​​of different tissues, initially separate the tissues around the maxillary sinus, erase excess parts or fill in missing parts, and perform smoothing to obtain the three-dimensional model contour of the maxillary sinus.

[0038] The present invention also discloses an electronic device, including a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus;

[0039] The memory is used to store computer programs;

[0040] When the processor executes the program stored in the memory, it implements the method for constructing a maxillary sinus lift model using the inverse three-dimensional finite element method and hydraulic lifting method as described in this invention.

[0041] The present invention also discloses one or more computer-readable media having instructions stored thereon that, when executed by one or more processors, cause the processors to perform a method for constructing a maxillary sinus lift model as described in the present invention using the inverse three-dimensional finite element method and hydraulic lifting method.

[0042] This invention has the following advantages:

[0043] This invention discloses a method for constructing a maxillary sinus elevation model using a reverse 3D finite element method and a hydraulic lifting method. The method involves acquiring CBCT images of the maxilla, extracting the 3D contour of the maxillary sinus model, and performing 3D reverse reconstruction to generate 3D models of cortical bone, cancellous bone, and mucosa. Subsequently, a maxillary sinus elevation channel model is established, assembled into a complete 3D maxillary sinus model, and assigned material parameters and contact relationships. A finite element model is obtained using tetrahedral meshing, and then the model is obtained by simulating hydraulic lifting loading and iteratively solving the problem. This method, compared to the traditional impact method, has lower operational difficulty and risk, is safer, and solves the problems of nonlinear large deformation and complex contact behavior, thereby improving the accuracy and stability of the simulation results. Attached Figure Description

[0044] Figure 1 This is a flowchart of the steps of the method for constructing a maxillary sinus lift model using the reverse three-dimensional finite element method and hydraulic lifting method provided by the present invention;

[0045] Figure 2 This is a schematic diagram of the three-dimensional model outline of the maxillary sinus provided by the present invention;

[0046] Figure 3 This is a three-dimensional graphic reference diagram of the maxilla provided by the present invention;

[0047] Figure 4This is a reference schematic diagram of a three-dimensional solid model of cancellous bone and mucosa provided by the present invention;

[0048] Figure 5 This is a schematic diagram of the bone chisel provided by the present invention;

[0049] Figure 6 This is a reference schematic diagram of the maxillary sinus assembly entity provided by the present invention;

[0050] Figure 7 This is a reference schematic diagram of the other side of the maxillary sinus assembly entity provided by the present invention;

[0051] Figure 8 This is a reference schematic diagram of the maxillary sinus finite element model provided by the present invention;

[0052] Figure 9 This is a reference schematic diagram of the other side of the maxillary sinus finite element model provided by the present invention;

[0053] Figure 10 This is a reference schematic diagram of the contact surface structure provided by the present invention;

[0054] Figure 11 This is the finite element cross-sectional view of M1 provided by the present invention;

[0055] Figure 12 This is the M1 calculation convergence graph provided by the present invention;

[0056] Figure 13 This is the M2 finite element cross-sectional view provided by the present invention;

[0057] Figure 14 This is the M2 calculation convergence graph provided by the present invention;

[0058] Figure 15 This is the M3 finite element cross-sectional view provided by the present invention;

[0059] Figure 16 This is the M3 calculation convergence graph provided by the present invention. Detailed Implementation

[0060] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0061] Reference Figure 1 The flowchart illustrates the steps of the method for constructing a maxillary sinus lift model using the inverse three-dimensional finite element method and hydraulic lifting method provided in an embodiment of the present invention. Specifically, it may include the following steps:

[0062] Step 101: Acquire CBCT images of the maxilla and extract the three-dimensional model contour of the maxillary sinus from the CBCT images of the maxilla;

[0063] Step 102: Perform three-dimensional reverse reconstruction on the contour of the maxillary sinus three-dimensional model to generate a three-dimensional model of cortical bone, a three-dimensional model of cancellous bone, and a three-dimensional model of mucosa. Then, perform feature recognition and surface diagnosis on the three-dimensional models of cortical bone, cancellous bone, and mucosa to repair the flawed surfaces.

[0064] Step 103: Establish a three-dimensional model of the maxillary sinus elevation channel, and assemble the three-dimensional models of cortical bone, cancellous bone, mucosa, and maxillary sinus elevation channel into a three-dimensional model of the maxillary sinus.

[0065] Step 104: Assign corresponding material parameters and contact relationships to the three-dimensional cortical bone model, cancellous bone model, mucosa model, and maxillary sinus elevation channel model of the three-dimensional model of the maxillary sinus, respectively, and divide the three-dimensional model of the maxillary sinus using a tetrahedral mesh to obtain a three-dimensional finite element model of the maxillary sinus.

[0066] Step 105: A loading surface is formed on the mucosal surface of the three-dimensional finite element model of the maxillary sinus by projecting the channel through it. The loading surface is then subjected to load by simulating hydraulic lifting. Meanwhile, the Mooney-Rivlin model and the updated Lagrange method are used for iterative solution in the finite element analysis until the calculation converges, thus obtaining the maxillary sinus lifting model.

[0067] This invention acquires CBCT images of the maxilla, which serve as the foundational data for constructing a three-dimensional model of the maxillary sinus. From the CBCT images, the three-dimensional contour of the maxillary sinus can be accurately extracted. Next, a three-dimensional reverse reconstruction of the maxillary sinus contour is performed to generate three-dimensional models of the cortical bone, cancellous bone, and mucosa. To ensure the accuracy and reliability of the model, feature recognition and surface diagnosis are further performed on the geometric model, problematic surfaces are repaired, and the remaining maxillary sinus models are then constructed. A three-dimensional model of the maxillary sinus lift channel is created, and then the assembly interface is used to adjust the positions. Based on the grouping, the cortical bone, maxillary sinus membrane, and bone chisel are assembled into a complete entity.

[0068] In the assembled 3D model of the maxillary sinus, each component is assigned corresponding material parameters and contact relationships, which reflect the physical properties of the tissue. Then, a tetrahedral mesh is used to divide the entire 3D model of the maxillary sinus, resulting in a 3D finite element model of the maxillary sinus.

[0069] Finally, a loading surface is formed on the mucosal surface using channel projection, and the hydraulic lifting is simulated to apply a load to the loading surface. The elastic modulus is a physical quantity describing the elasticity of a solid material; it reflects the ease with which a material changes shape or size when subjected to external forces. The main characteristic of liquids is their fluidity. Therefore, when subjected to external forces, liquids do not resist the force by restoring their original shape but rather flow to adapt to the direction of the force. Thus, from a physics perspective, liquids do not possess an elastic modulus in the traditional sense because they lack the ability to restore their original shape like solids. In the three-dimensional finite element model, pressure loads can be directly applied to the liquid's boundaries. In the finite element analysis, the Mooney-Rivlin model and the updated Lagrangian method are used for iterative solutions until convergence. This process simulates an actual hydraulic lifting surgery and yields a maxillary sinus lift model. This step serves to predict the surgical outcome and provide valuable reference information for the surgeon.

[0070] This invention utilizes CBCT images of the maxilla and performs three-dimensional reverse reconstruction to generate a high-precision three-dimensional model of the maxillary sinus, including key structures such as cortical bone, cancellous bone, mucosa, and the maxillary sinus lift channel. This significantly improves the accuracy and reliability of the model, providing a solid foundation for subsequent finite element analysis. Secondly, the method employs tetrahedral meshing of the maxillary sinus three-dimensional model and combines the Mooney-Rivlin model with the updated Lagrange method for iterative solution, enabling more accurate simulation of biomechanical changes during maxillary sinus lift surgery. This method not only considers the nonlinear stress-strain relationship of the material but also handles large deformation problems and complex contact behaviors, thereby improving the accuracy and stability of the simulation results.

[0071] In one embodiment of the present invention, the mucosa is set to the C10 and C01 parameters of Hyperelastic; the cortical bone and cancellous bone are in bonded contact, and the cortical bone and mucosa are in frictionless contact; when simulating different degrees of mucosal separation, the unseparated mucosal area and the corresponding maxillary bone area are treated as having shared nodes, while the separated mucosal area and the corresponding maxillary bone area are treated as having no contact and no shared nodes.

[0072] The maxillary sinus mucosa is a complex soft tissue material exhibiting large deformation and nonlinearity. In this embodiment, the mucosa is set to have C10 and C01 parameters of hyperelasticity. The contact settings for the cortical bone, cancellous bone, and mucosa are as follows: cortical bone and cancellous bone are in bonded contact, while cortical bone and mucosa are in frictionless contact to ensure accurate force transmission. When simulating different degrees of mucosal separation, the unseparated mucosal region shares nodes with the corresponding maxillary bone region, while the separated mucosal region does not contact or share nodes with the corresponding maxillary bone region.

[0073] In one embodiment of the present invention, the loading method is a force load; the force load mode is a quasi-static loading mode starting from 0 kPa and with a rate of 0.1 mm / s; the direction in which the liquid applies uniform pressure to the loading surface is vertical and lateral.

[0074] Three-dimensional finite element method (3D FE) loading methods are mainly divided into force loading and displacement loading. Force loading mainly studies the strain of a material when different forces are applied, while displacement loading mainly studies the strain of a material after it has been forcibly displaced to a specified position. Based on preliminary experiments, displacement loading is not suitable for 3D FE study of the hydraulic lifting method. Displacement loading requires setting the bottom area and height of the loading, and during the loading process, the bottom area remains unchanged while all nodes of the material are forced to the specified height. In hydraulic lifting, due to the strong fluidity of the liquid, the bottom area constantly changes; the irregular shape of the sinus bottom and the hyperelastic properties of the mucosa cause the lifting height to vary at different locations, resulting in a significant difference between the displacement loading model and reality. Therefore, this invention chooses force loading as the main loading method.

[0075] In the context of loading, loads are generally categorized into dynamic loads, static loads, and quasi-static loads, which describe the nature and effect of forces acting on an object. Dynamic loads are loads whose magnitude, direction, or point of application changes over time. A characteristic of this type of load is that it leads to a dynamic response in the structure, meaning that the deformation and stress distribution of the structure change over time. Dynamic loads are typically applied over a very short period. Static loads are loads applied slowly to a structure, and whose magnitude and direction do not change during the application process. A characteristic of this type of load is that the structural response is essentially static during the application time; that is, the deformation and stress distribution of the structure remain constant over time. Quasi-static loading is a method used to simulate static problems. By applying slowly varying loads to the finite element model, it is ensured that the structural response is close to a static equilibrium state at any given moment. The key to this method is setting appropriate parameters, such as loading rate and analysis step time, to prevent potential localized deformation problems caused by excessively rapid loading. Currently, dynamic loading is more frequently used to study the effects of chewing processes and traumatic impacts. Static loading primarily assesses the stress distribution of implants or restorations under different directions, such as vertical loading and buccal-lingual loading. Because hydraulic lifting requires a slower fluid injection rate, a quasi-static load is more suitable for the characteristics of the hydraulic lifting process.

[0076] This embodiment adopts a quasi-static loading method of mechanical loading, applying uniform pressure to the liquid boundary and subjecting the model to quasi-static loading. Specifically, the force loading mode is a quasi-static loading mode starting from 0 kPa and with a rate of 0.1 mm / s; the direction of the uniform pressure applied by the liquid to the loading surface is vertical and lateral. Finally, the calculation was successful and convergent experimental results were obtained.

[0077] In one embodiment of the present invention, in the initial stage of lifting, the stress concentration point of the maxillary sinus mucosa is in the center of the force application point. As the lifting height increases, the stress concentration point spreads from the center to the surrounding area.

[0078] Finite element analysis results show that when the maxillary sinus mucosa is lifted to the same height, the horizontal strain of the maxillary sinus mucosa using the hydraulic lifting method is significantly greater than that using the impact method. The equivalent stress, tensile stress, compressive stress, and shear force are all lower in the hydraulic lifting method than in the impact method, and these differences are statistically significant. In the initial stage of lifting, the stress concentration point of the maxillary sinus mucosa using the hydraulic lifting method is in the center of the application point; as the lifting height increases, the stress concentration point diffuses from the center outwards. In contrast, in the impact method, the stress concentration point is around the application point in the initial stage of lifting; as the lifting height increases, the stress concentration point concentrates from the periphery towards the center. Therefore, the hydraulic lifting method is safer than the impact method.

[0079] In one embodiment of the present invention, the contour of the maxillary sinus three-dimensional model is reconstructed in three dimensions to generate a three-dimensional model of cortical bone, a three-dimensional model of cancellous bone, and a three-dimensional model of mucosa, including:

[0080] The contour of the three-dimensional model of the maxillary sinus is finely segmented to distinguish the cortical bone region, the cancellous bone region, and the mucosal region;

[0081] The cortical bone region, cancellous bone region, and mucosa region were smoothed, denoised, surface constructed, gridded, and solidified respectively to generate three-dimensional models of cortical bone, cancellous bone, and mucosa; the mucosa thickness was set to 1 mm.

[0082] In one embodiment of the present invention, the three-dimensional model of the maxillary sinus lift channel is a cylindrical hole with a diameter of 4 mm.

[0083] In this embodiment of the invention, a three-dimensional reverse reconstruction technique is used to construct a three-dimensional model of the maxillary sinus. This allows for fine segmentation of the extracted three-dimensional maxillary sinus model contour, clearly distinguishing the cortical bone region, cancellous bone region, and mucosa region. Subsequently, smoothing, surface construction, gridding, and solidification operations are performed on these three regions respectively to generate three-dimensional models of the cortical bone, cancellous bone, and mucosa, where the mucosa thickness can be set to 1 mm. Furthermore, during the construction of the three-dimensional maxillary sinus model, a cylindrical hole with a diameter of 4 mm is designed as a three-dimensional model of the maxillary sinus elevation channel. Thus, these established three-dimensional models can be assembled to obtain a three-dimensional model of the frontal sinus.

[0084] In one embodiment of the present invention, acquiring CBCT images of the maxilla and extracting the three-dimensional model contour of the maxillary sinus from the CBCT images of the maxilla includes:

[0085] Scanning the maxilla yields CBCT images of the maxilla;

[0086] The maxillary CBCT image is automatically thresholded based on the gray values ​​of different tissues to initially separate the tissues around the maxillary sinus. Excess parts are erased or missing parts are added, and smoothing is performed to obtain the three-dimensional model outline of the maxillary sinus.

[0087] In an embodiment of the present invention, the maxilla of a volunteer is scanned by CT scan, and the obtained DICOM format file is input into a three-dimensional reconstruction software for processing as follows: 1) Automatic thresholding is performed based on the gray values ​​of different tissues to initially separate the tissues around the maxillary sinus; 2) The model is smoothed by using manual layer editing tools to erase excess or fill in missing parts, extracting the outline of the entire three-dimensional model of the maxillary sinus, and exporting it as an STL format file.

[0088] The following example illustrates the experimental process of constructing a maxillary sinus lift model using the inverse three-dimensional finite element method and hydraulic lifting method of this invention, and provides a comparative analysis with the maxillary sinus lift model constructed by the impact method:

[0089] This experiment reconstructed a three-dimensional model of the maxillary sinus using CBCT scan data. It fully utilized various modeling software, simplifying the tedious image processing and conversion process and significantly improving the model's accuracy. The experiment used Mimics software to quickly and accurately establish a preliminary model of the human maxillary sinus, and then used Geomagic software to optimize and smooth the model, successfully establishing a three-dimensional finite element model of the maxillary sinus. Finally, the model was imported into ANSYS finite element software for relevant stress analysis, which can measure the stress at each point or surface and simulate any form of pressure.

[0090] 1.1 Experimental Objective

[0091] We established and analyzed the maxillary sinus lift models using inverse three-dimensional finite element method, hydraulic lifting method, and impact method, and verified them for future research.

[0092] 1.2. Experimental Subjects

[0093] The study selected imaging data of the maxillary sinus from a 26-year-old female patient who was missing her left maxillary first molar. The patient's maxillary sinus morphology was C3 type.

[0094] 1.3. Materials and Methods

[0095] 1.3.1 Experimental Equipment

[0096] Laptop: Basic configuration includes Intel i7 processor, 32GB RAM, 256GB SSD, 1TB HDD, and Windows 10 operating system.

[0097] 1.3.2 Experimental Grouping

[0098] M1: Hydraulic lifting method; M2: M3: Direct impact of the maxillary sinus floor mucosa using a jacking device; The ramming device is used for direct impact on the maxillary sinus floor mucosa.

[0099] 1.3.3 Modeling Process

[0100] (1) Processing of CT files

[0101] Using CT scans of volunteers' maxillae, the obtained DICOM format files were input into 3D reconstruction software, and the following processes were performed sequentially: 1) Automated thresholding was performed based on the grayscale values ​​of different tissues to initially separate the tissues surrounding the maxillary sinus; 2) Excess or missing parts were erased using manual layer editing tools, the model was smoothed, the entire 3D model outline of the maxillary sinus was extracted, and the model was exported as an STL format file, such as... Figure 2 As shown.

[0102] (2) 3D solid reconstruction

[0103] Import the obtained STL file into reverse engineering software. Perform a series of image processing steps on the 3D model, including smoothing and denoising, surface construction, gridding, and solidification, to generate a 3D maxillary bone graphic in IGES file format. Figure 3 As shown. Three-dimensional solid models of cancellous bone and mucosa were obtained using the same method, as shown. Figure 4 As shown, the mucosal thickness is set to 1 mm. A cylindrical opening with a diameter of 4.0 mm is created as a maxillary sinus elevation channel.

[0104] (3) Model assembly

[0105] Impact method: Two different diameters were drawn using drawing software. and Summers bone chisels, such as Figure 5 As shown.

[0106] Import the geometric model file generated by the 3D solid reconstruction software into SolidWorks software. Perform feature recognition and surface diagnosis on the geometric model, repair problematic surfaces, and then use the feature / surface module in the part interface to create the remaining models of the maxillary sinus. Enter the assembly interface to adjust the position, and assemble the cortical bone, cancellous bone, maxillary sinus membrane, and maxillary sinus lift channel or bone chisel into a complete solid according to the grouping. Refer to... Figure 6 and Figure 7 .

[0107] (4) Grid generation

[0108] The cortical bone, pine branch bone, and mucosa assembly models were assigned appropriate material parameters and contact relationships were set. Then, meshing was performed using tetrahedral meshes with a mesh size of 0.5 mm. The final three-dimensional finite element model was thus established. (Refer to...) Figure 8 and Figure 9 The number of nodes and units is shown in Table 1.

[0109] Table 1 shows the number of nodes and units.

[0110]

[0111] (5) Material properties

[0112] The IGES format data was imported into the three-dimensional finite element analysis software. Values ​​were assigned to the cortical bone, cancellous bone, maxillary sinus mucosa, and punch, as shown in Table 2. In this study, the maxillary sinus mucosa was set to hyperelastic parameters C10 and C01. To improve computational accuracy, convergence, and efficiency, the cortical bone, cancellous bone, and mucosa were divided into tetrahedral mesh elements, and the punch was also divided into tetrahedral mesh elements.

[0113] Table 2 Material Elastic Modulus, Poisson's Ratio, and Element Type

[0114]

[0115] (6) Contact settings

[0116] The cortical bone and cancellous bone are in bonded contact, while the cortical bone and mucosa are in frictionless contact. The tip of the punch and the mucosa are in frictional contact with a coefficient of friction of 0.2. The periphery of the punch does not contact the prepared cavity area of ​​the maxilla. The separated and unseparated mucosa are treated as sharing nodes to ensure realistic force transmission. When simulating different degrees of mucosal separation, the unseparated mucosal area and the corresponding maxillary bone area are treated as sharing nodes, while the separated mucosal area and the corresponding maxillary bone area are not in contact or shared nodes.

[0117] (7) Constraints and Loads

[0118] Assuming the maxilla and the impactor are isotropic, homogeneous, and continuous linear elastic materials, and the mucosa is set as a hyperelastic material, the impactor is only allowed vertical displacement during the simulated impact process, with lateral displacement restricting its degrees of freedom. During hydraulic lifting, the fluid is allowed both vertical and lateral displacement. Force load is selected as the load type.

[0119] (8) Solve

[0120] The solution process is performed using a large deformation nonlinear iterative method within the ANSYS solution module.

[0121] Description of strain and stress under large deformation conditions:

[0122] ①Green strain is defined as

[0123]

[0124] In the formula, δ ij Kronecher symbol; u i =x i (X i ,t)-X j The displacement vector defined in the initial configuration.

[0125] The material derivative of Green strain is:

[0126]

[0127] ②Cauchy stress is directed onto surface element n in the current configuration. i The force ΔT acting on ΔA i Under extreme conditions,

[0128]

[0129] n i The stress vector t on dA i (n) Represented by stress vectors on three surface elements perpendicular to the coordinate axes, we have t i (n) =σ ij n j That is, the Cauchy stress tensor, σ ij The stress is defined as the stress per unit area on the current configuration, and is the real stress related to deformation.

[0130] Contact interface algorithm selection: This invention primarily uses the symmetric penalty function method for calculation. All contact elements employ penalty stiffness (contact stiffness to ensure the compatibility of the contact interface), referring to... Figure 10 .

[0131] (9) Three-dimensional finite element analysis

[0132] Three-dimensional finite element simulation process of hydraulic impact method: ① Construction of the loading surface: The loading surface is formed on the mucosa surface by projecting the channel. ② Uniform pressure is applied to the constructed loading surface, with the direction perpendicular to the loading surface (the pressure of the liquid on the surface is perpendicular to the contact surface). Quasi-static loading mode starts from 0 kPa and has a rate of 0.1 mm / s.

[0133] The three-dimensional finite element simulation process of the impact method: The impact method does not require the construction of a loading surface; pressure is applied directly to the impactor. Here, pressure = impactor area x hydraulic value.

[0134] 1.4 Results

[0135] The liquid and the impeller simulated the upward movement and deformation of the maxillary sinus floor mucosa, achieving a similar effect to the mucosal elevation in clinical maxillary sinus lift surgery, and yielded convergent experimental results. The hydraulic lift method and the impact method for maxillary sinus lift model were successfully constructed.

[0136] M1 finite element simulation diagram:

[0137] Figure 11 A represents the total strain of the maxillary sinus mucosa (X-axis); B represents the von Mises stress distribution (coronal plane); C represents the von Mises stress distribution (view from below).

[0138] The convergence graph of M1 calculation is as follows: Figure 12 As shown.

[0139] M2 finite element simulation diagram:

[0140] Figure 13 A represents the total strain of the maxillary sinus mucosa (X-axis); B represents the von Mises stress distribution (coronal plane); C represents the von Mises stress distribution (view from below).

[0141] The convergence graph of M2 calculation is as follows: Figure 14 As shown.

[0142] M3 finite element simulation diagram:

[0143] Figure 15 A represents the total strain of the maxillary sinus mucosa (X-axis); B represents the von Mises stress distribution (coronal plane); C represents the von Mises stress distribution (view from below).

[0144] The convergence graph of M3 calculation is as follows: Figure 16 As shown.

[0145] The finite element analysis results show that when the maxillary sinus mucosa is lifted to the same height, the horizontal strain of the maxillary sinus mucosa under the hydraulic lifting method is significantly greater than that under the impact method, while the equivalent stress, tensile stress, compressive stress, and shear force are all lower under the hydraulic lifting method, with statistically significant differences. In the initial stage of lifting, the stress concentration point of the maxillary sinus mucosa under the hydraulic lifting method is at the center of the application point; as the lifting height increases, the stress concentration point diffuses from the center outwards. In contrast, under the impact method, the stress concentration point is around the application point in the initial stage of lifting; as the lifting height increases, the stress concentration point converges from the periphery towards the center. This study indicates that the hydraulic lifting method is safer than the impact method.

[0146] This study employed the Mooney-Rivlin model and the Updated Lagrangian Approach for computation, methods capable of handling large deformations of materials and structures during loading. Adaptive mesh refinement techniques were used to ensure sufficient mesh density in areas of significant deformation to capture details, while reducing the mesh count in areas of less deformation to conserve computational resources. By fitting, relatively similar C10 and C01 parameters for hyperelasticity were obtained. The study qualitatively investigated the stress characteristics of the maxillary sinus mucosa under different lifting methods. The computation was successful, and convergent experimental results were obtained. The trends in stress and displacement values ​​at the interface demonstrate the rationality of the experimental parameter design and provide guidance for clinical procedures. Furthermore, the study verified that the model established using the hydraulic lifting method possesses good geometric and biomechanical similarity.

[0147] It should be noted that, for the sake of simplicity, the method embodiments are all described as a series of actions. However, those skilled in the art should understand that the embodiments of the present invention are not limited to the described order of actions, because according to the embodiments of the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions involved are not necessarily essential to the embodiments of the present invention.

[0148] This invention also provides an apparatus for constructing a maxillary sinus lift model using inverse three-dimensional finite element method and hydraulic lifting method, which may specifically include the following modules:

[0149] The maxillary sinus contour extraction module is used to acquire maxillary bone CBCT images and extract the three-dimensional model contour of the maxillary sinus from the maxillary bone CBCT images;

[0150] The three-dimensional reverse reconstruction module is used to perform three-dimensional reverse reconstruction of the contour of the maxillary sinus three-dimensional model, generate a three-dimensional model of cortical bone, a three-dimensional model of cancellous bone, and a three-dimensional model of mucosa, and repair the flawed surfaces of the three-dimensional models of cortical bone, cancellous bone, and mucosa through feature recognition and surface diagnosis.

[0151] The solid assembly module is used to create a three-dimensional model of the maxillary sinus lift channel and assemble the three-dimensional models of cortical bone, cancellous bone, mucosa, and maxillary sinus lift channel into a three-dimensional model of the maxillary sinus.

[0152] The maxillary sinus three-dimensional finite element model construction module is used to assign corresponding material parameters and contact relationships to the three-dimensional cortical bone model, cancellous bone model, mucosa model, and maxillary sinus elevation channel model of the maxillary sinus three-dimensional model, respectively, and to divide the maxillary sinus three-dimensional model using a tetrahedral mesh to obtain the maxillary sinus three-dimensional finite element model.

[0153] The hydraulic lifting and finite element analysis module is used to form a loading surface on the mucosal surface of the three-dimensional finite element model of the maxillary sinus by projecting the channel, and to simulate the hydraulic lifting to apply load to the loading surface. At the same time, the Mooney-Rivlin model and the updated Lagrange method are used for iterative solution in the finite element analysis until the calculation converges to obtain the maxillary sinus lifting model.

[0154] Optionally, the mucosa is set to the C10 and C01 parameters of Hyperelastic; the cortical bone and cancellous bone are in bonded contact, and the cortical bone and mucosa are in frictionless contact; when simulating different degrees of mucosal separation, the unseparated mucosal area and the corresponding maxillary bone area are treated as having shared nodes, while the separated mucosal area and the corresponding maxillary bone area are treated as having no contact and no shared nodes.

[0155] Optionally, the loading method is a force load; the force load mode is a quasi-static loading mode starting from 0 kPa and with a rate of 0.1 mm / s; the direction in which the liquid applies uniform pressure to the loading surface is vertical and lateral.

[0156] Optionally, the three-dimensional model of the maxillary sinus elevation channel is a cylindrical hole with a diameter of 4 mm.

[0157] Optionally, in the initial stage of lifting, the stress concentration point of the maxillary sinus mucosa is in the center of the force application point. As the lifting height increases, the stress concentration point spreads from the center to the surrounding areas.

[0158] Optionally, the three-dimensional reverse reconstruction module includes:

[0159] The region segmentation submodule is used to finely segment the contour of the three-dimensional model of the maxillary sinus, distinguishing the cortical bone region, cancellous bone region and mucosal region.

[0160] The 3D model generation submodule is used to perform smoothing, noise reduction, surface construction, gridding, and solidification operations on the cortical bone region, cancellous bone region, and mucosa region respectively, to generate 3D models of cortical bone, cancellous bone, and mucosa; the mucosa thickness is set to 1mm.

[0161] Optionally, the maxillary sinus contour extraction module includes:

[0162] The maxillary CBCT image acquisition submodule is used to scan the maxilla to obtain maxillary CBCT images;

[0163] The maxillary sinus contour extraction submodule is used to automatically threshold the maxillary bone CBCT image according to the gray values ​​of different tissues, initially separate the tissues around the maxillary sinus, erase excess parts or fill in missing parts, and perform smoothing to obtain the three-dimensional model contour of the maxillary sinus.

[0164] As the device embodiment is basically similar to the method embodiment, the description is relatively simple, and relevant parts can be found in the description of the method embodiment.

[0165] In addition, embodiments of the present invention also provide an electronic device, including a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus.

[0166] Memory, used to store computer programs;

[0167] When the processor executes the program stored in the memory, it implements the method for constructing a maxillary sinus lift model using the inverse three-dimensional finite element method and the hydraulic lifting method as described in the above embodiments.

[0168] The communication bus mentioned above can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, only one thick line is used to represent it in the diagram, but this does not mean that there is only one bus or one type of bus.

[0169] The communication interface is used for communication between the aforementioned terminal and other devices.

[0170] The memory may include random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0171] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0172] In another embodiment of the present invention, a computer-readable storage medium is also provided, which stores instructions that, when executed on a computer, cause the computer to perform the method for constructing a maxillary sinus lift model using the inverse three-dimensional finite element method and hydraulic lifting method described in the above embodiments.

[0173] In another embodiment of the present invention, a computer program product containing instructions is also provided, which, when run on a computer, causes the computer to execute the method for constructing a maxillary sinus lift model using the inverse three-dimensional finite element method and hydraulic lifting method described in the above embodiments.

[0174] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (SSD)).

[0175] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0176] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the apparatus embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0177] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A method of constructing a maxillary sinus lift model using inverse three-dimensional finite element and hydraulic lifting method, characterized in that, The method comprises: Collecting a maxillary CBCT image, and extracting a maxillary sinus three-dimensional model contour from the maxillary CBCT image; Three-dimensional reverse reconstruction is performed on the maxillary sinus three-dimensional model contour to generate a cortical bone three-dimensional model, a cancellous bone three-dimensional model and a mucosa three-dimensional model, and the cortical bone three-dimensional model, the cancellous bone three-dimensional model and the mucosa three-dimensional model are repaired by feature recognition and surface diagnosis to repair the surface with defects; A maxillary sinus lifting channel three-dimensional model is established, and the cortical bone three-dimensional model, the cancellous bone three-dimensional model, the mucosa three-dimensional model and the maxillary sinus lifting channel three-dimensional model are assembled into a maxillary sinus three-dimensional model; Corresponding material parameters and contact relationships are respectively given to the cortical bone three-dimensional model, the cancellous bone three-dimensional model, the mucosa three-dimensional model and the maxillary sinus lifting channel three-dimensional model of the maxillary sinus three-dimensional model, and the maxillary sinus three-dimensional model is divided into a tetrahedral mesh to obtain a maxillary sinus three-dimensional finite element model; A loading surface is formed by projecting a channel on the mucosa surface of the maxillary sinus three-dimensional finite element model, and a hydraulic lifting load is applied to the loading surface, and a Mooney-Rivlin model and an updated Lagrangian method are used for iterative solving in finite element analysis until convergence is achieved to obtain a maxillary sinus lifting model; The mucosa is set as C10 and C01 parameters of hyperelasticity; the cortical bone and the cancellous bone are in bonded contact, and the cortical bone and the mucosa are in frictionless contact; when the mucosa is simulated to be separated to different degrees, the non-separated mucosa region and the corresponding maxillary bone region are treated as shared nodes, and the separated mucosa region and the corresponding maxillary bone region are not in contact and are not treated as shared nodes; The three-dimensional reverse reconstruction of the maxillary sinus three-dimensional model contour generates a cortical bone three-dimensional model, a cancellous bone three-dimensional model and a mucosa three-dimensional model, which comprises: The maxillary sinus three-dimensional model contour is finely segmented to distinguish the cortical bone region, the cancellous bone region and the mucosa region; The cortical bone region, the cancellous bone region and the mucosa region are respectively subjected to smoothing denoising, surface construction, gridding and solidification to generate a cortical bone three-dimensional model, a cancellous bone three-dimensional model and a mucosa three-dimensional model; the mucosa thickness is set as 1 mm; The maxillary CBCT image is collected, and the maxillary sinus three-dimensional model contour is extracted from the maxillary CBCT image, which comprises: The maxillary bone is scanned to obtain a maxillary CBCT image; The maxillary CBCT image is automatically thresholded according to the gray values of different tissues, the tissues around the maxillary sinus are preliminarily separated, and the excess part is erased or the missing part is supplemented, and smoothing processing is performed to obtain the maxillary sinus three-dimensional model contour.

2. The method of claim 1, wherein, The load mode is force loading; the force loading mode is a quasi-static loading mode starting from 0 kPa at a rate of 0.1 mm / s; the direction in which the liquid applies uniform pressure to the loading surface is vertical and lateral.

3. The method of claim 1, wherein, The maxillary sinus lifting channel three-dimensional model is a cylindrical hole with a diameter of 4 mm.

4. The method of claim 1, wherein, In the initial lifting stage, the stress concentration point of the maxillary sinus mucosa is in the center of the force point, and as the lifting height increases, the stress concentration point spreads from the center to the periphery.

5. Apparatus for constructing a maxillary sinus lift model using inverse three-dimensional finite elements and hydraulic lifting, characterized in that, The device comprises: a maxillary sinus profile extraction module, configured to collect a maxillary bone CBCT image and extract a maxillary sinus three-dimensional model profile from the maxillary bone CBCT image; a three-dimensional reverse reconstruction module, configured to perform three-dimensional reverse reconstruction on the maxillary sinus three-dimensional model profile to generate a cortical bone three-dimensional model, a cancellous bone three-dimensional model and a mucosa three-dimensional model, and to perform feature recognition and surface diagnosis on the cortical bone three-dimensional model, the cancellous bone three-dimensional model and the mucosa three-dimensional model to repair flawed surfaces; a solid assembly module, configured to establish a maxillary sinus lifting channel three-dimensional model, and assemble the cortical bone three-dimensional model, the cancellous bone three-dimensional model, the mucosa three-dimensional model and the maxillary sinus lifting channel three-dimensional model into a maxillary sinus three-dimensional model; a maxillary sinus three-dimensional finite element model construction module, configured to respectively assign corresponding material parameters and contact relations to the cortical bone three-dimensional model, the cancellous bone three-dimensional model, the mucosa three-dimensional model and the maxillary sinus lifting channel three-dimensional model of the maxillary sinus three-dimensional model, and to divide the maxillary sinus three-dimensional model by using a tetrahedral mesh to obtain a maxillary sinus three-dimensional finite element model; a hydraulic lifting and finite element analysis module, configured to project a channel on a mucosa surface of the maxillary sinus three-dimensional finite element model to form a loading surface, simulate hydraulic lifting to apply a load to the loading surface, and perform iterative solving by using a Mooney-Rivlin model and an updated Lagrangian method in finite element analysis until calculation converges to obtain a maxillary sinus lifting model; C10 and C01 parameters of the mucosa are set as hyperelastic; the cortical bone and the cancellous bone are in bound contact, and the cortical bone and the mucosa are in frictionless contact; when the mucosa is simulated to be separated to different degrees, the non-separated mucosa region and the corresponding maxillary bone region are handled as sharing nodes, and the separated mucosa region and the corresponding maxillary bone region are handled as not in contact and not sharing nodes; the three-dimensional reverse reconstruction module comprises: a region division sub-module, configured to finely segment the maxillary sinus three-dimensional model profile to distinguish a cortical bone region, a cancellous bone region and a mucosa region; a three-dimensional model generation sub-module, configured to respectively perform smooth denoising, surface construction, gridding and solidification operations on the cortical bone region, the cancellous bone region and the mucosa region to generate a cortical bone three-dimensional model, a cancellous bone three-dimensional model and a mucosa three-dimensional model; and the mucosa thickness is set as 1 mm; the maxillary sinus profile extraction module comprises: a maxillary bone CBCT image collection sub-module, configured to scan a maxillary bone to obtain a maxillary bone CBCT image; a maxillary sinus profile extraction sub-module, configured to automatically separate different tissues of the maxillary bone CBCT image by thresholding, preliminarily separate surrounding tissues of the maxillary sinus, erase redundant parts or supplement missing parts, and perform smoothing processing to obtain the maxillary sinus three-dimensional model profile.

6. An electronic device, comprising: a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory complete communication with each other through the communication bus; the memory is used to store a computer program. The processor is configured to implement the method of constructing a maxillary sinus lifting model by inverse three-dimensional finite element and hydraulic lifting method according to any one of claims 1-4 when executing the program stored in the memory.

7. One or more computer-readable media having instructions stored thereon that, when executed by one or more processors, cause the processors to perform the method of constructing a maxillary sinus lifting model by inverse three-dimensional finite element and hydraulic lifting method according to any one of claims 1-4.

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