A dynamic simulation method and system for tooth movement process based on a typodont model

Abstract

The application relates to a dynamic simulation method and system for tooth movement based on a Typodont model, which comprises the following steps: collecting data of artificial teeth and fixed appliances through three-dimensional scanning to obtain three-dimensional data of a dental arch structure; performing superposition analysis on a crown-root model according to the three-dimensional data to obtain a digital dental arch model containing periodontal tissue; assigning material attributes to anatomical structures in the digital dental arch model according to preset material parameters to obtain a biomechanical dental arch model; performing time recursion iteration on the biomechanical dental arch model through finite element analysis to obtain four-dimensional dynamic simulation data simulating a tooth movement process, and providing visual orthodontic process teaching demonstration based on the four-dimensional dynamic simulation data. The application realizes dynamic visual simulation of the tooth movement process, can quantize feedback of the Typodont system, and improves teaching interactivity.

Description

Technical Field

[0001] This invention relates to the field of orthodontic technology, and in particular to a dynamic simulation method and system for tooth movement based on the Typodont model. Background Technology

[0002] Typodont models are an important tool in orthodontic teaching. To help orthodontic beginners intuitively understand the principles of orthodontic mechanics and improve operational precision, traditional Typodont training involves bonding brackets and placing archwires on the model, and using a water bath to heat the wax model to simulate the movement of teeth under the action of the elastic archwire. This provides medical students with preclinical skills training, thereby improving their understanding of biomechanics and the accuracy of their operations.

[0003] For existing Typodont models, a combination of 3D scanning and reverse engineering techniques is typically used to digitize the Typodont before and after the experiment. Matching tooth models are then overlaid in software to create a 3D model of the dentition including the tooth roots. Subsequently, using the model's rigid base as a reference, the initial and final models are overlaid in Geomagic software. The displacement of each marker point is marked and measured, and the 3D movement of the teeth is quantitatively analyzed, thus providing a reference for clinical applications.

[0004] However, the three-dimensional dental arch model obtained by the above method can only present static results at two time points, and cannot reflect the dynamic changes of teeth during orthodontic treatment, nor can it simulate the real intraoral environment such as the periodontal ligament. Summary of the Invention

[0005] This invention provides a dynamic simulation method and system for tooth movement based on the Typodont model, in order to overcome the shortcomings of the prior art.

[0006] This invention provides a dynamic simulation method for tooth movement based on the Typodont model, comprising:

[0007] S1: Data acquisition of artificial teeth and fixed orthodontic appliances through 3D scanning to obtain 3D data of the dental and jaw structure;

[0008] S2: Based on the three-dimensional data, perform overlap analysis on the crown root model to obtain a digital dental model containing periodontal tissues;

[0009] S3: Assign material properties to the anatomical structures in the digital dental model according to preset material parameters to obtain a biomechanical dental model;

[0010] S4: The biomechanical dental model is iteratively analyzed over time using finite element analysis to obtain four-dimensional dynamic simulation data simulating the tooth movement process, and a visual orthodontic teaching demonstration is provided based on the four-dimensional dynamic simulation data.

[0011] According to the present invention, a dynamic simulation method for tooth movement based on the Typodont model is provided, wherein the three-dimensional data in step S1 is acquired by a first acquisition method or a second acquisition method.

[0012] According to the present invention, a dynamic simulation method for tooth movement based on the Typodont model is provided, wherein the first acquisition method further includes:

[0013] S111: The artificial tooth is scanned using a 3D scanner to obtain an STL model of the tooth;

[0014] S112: The artificial tooth is placed in a standard occlusal wax rim and a full dentition scan is performed to obtain three-dimensional data of the complete dentition.

[0015] S113: Obtain three-dimensional structural data of fixed orthodontic appliances by collecting original digital files of different types of brackets and archwires.

[0016] According to the present invention, a dynamic simulation method for tooth movement based on the Typodont model is provided, wherein the second acquisition method further includes:

[0017] S121: Scanning the subject using cone-beam CT to obtain raw tomographic data containing information about soft and hard tissues;

[0018] S122: Scan the subject's dentition using an intraoral scanner to obtain surface information of a digital dental model;

[0019] S123: Using a 3D scanner, different specifications of orthodontic appliances are scanned to obtain 3D data including straight wire brackets, square wire brackets, and archwires of different sizes.

[0020] According to the dynamic simulation method for tooth movement based on the Typodont model provided by the present invention, step S2 further includes:

[0021] S21: Using Geomagic software, tooth models at different stages are aligned at the crown to obtain the three-dimensional spatial relationship of the crown.

[0022] S22: Establish the spatial position of the tooth root structure based on the three-dimensional spatial positional relationship to obtain the tooth model;

[0023] S23: Add periodontal tissue structure data to the tooth model to obtain a digital dental model including the periodontal ligament, gingiva, and maxilla and mandible.

[0024] According to the dynamic simulation method for tooth movement based on the Typodont model provided by the present invention, step S3 specifically includes:

[0025] Linear elastic and isotropic material properties were assigned to both alveolar bone and teeth to obtain the first mechanical property model of hard tissue;

[0026] Homogeneous material properties were assigned to both the gingiva and periodontal ligament to obtain a second mechanical property model of the soft tissue.

[0027] By assigning material property values ​​to brackets and archwires of different specifications, a third mechanical property model of the orthodontic appliance is obtained.

[0028] According to the present invention, a dynamic simulation method for tooth movement based on the Typodont model is provided, wherein the elastic modulus of the periodontal ligament is assigned a value. MPa, Poisson's ratio assigned a value of 0.45; elastic modulus of cortical bone assigned a value of MPa, Poisson's ratio assigned a value of 0.30; elastic modulus of cancellous bone assigned a value of MPa, Poisson's ratio assigned a value of 0.30; the elastic modulus of the tooth assigned a value of MPa, with a Poisson's ratio of 0.30.

[0029] According to the dynamic simulation method for tooth movement based on the Typodont model provided by the present invention, step S4 further includes:

[0030] S41: Set the fixed constraints for the maxilla and mandible to obtain the model reference.

[0031] S42: By setting the fixed contact between the teeth and the bracket and the sliding contact with gap between the bracket and the archwire, the force transmission mechanism of the model is obtained;

[0032] S43: By simulating the process of the archwire recovering from its initial bent state to a straight state, load distribution data on multiple parts of the dental arch are obtained;

[0033] S44: Establish a dynamic simulation model based on the model reference, the model force transmission mechanism, and the load distribution data;

[0034] S45: The dynamic simulation model is used to simulate the tooth to be simulated, and four-dimensional dynamic simulation data of the tooth movement process is output.

[0035] According to the dynamic simulation method for tooth movement based on the Typodont model provided by the present invention, step S44 further includes:

[0036] S441: Orthodontic force is applied by the elastic deformation of the archwire and the initial displacement of the tooth under stress is calculated to obtain tooth movement data;

[0037] S442: Update the alveolar bone geometry based on the tooth movement data to obtain simulation results of bone resorption and reconstruction;

[0038] S443: By maintaining a constant periodontal ligament space, the periodontal ligament geometry is adjusted synchronously to obtain an updated simulation model;

[0039] S444: Iteratively update the simulation model to obtain a dynamic simulation model.

[0040] This invention also provides a dynamic simulation system for tooth movement based on the Typodont model, comprising:

[0041] Scanning module: Used to acquire data on artificial teeth and fixed orthodontic appliances through 3D scanning, and obtain 3D data of the dental and jaw structure;

[0042] Analysis module: used to perform overlap analysis on the crown root model based on the three-dimensional data to obtain a digital dental model containing periodontal tissues;

[0043] Assignment module: used to assign material properties to the anatomical structures in the digital dental model according to preset material parameters, so as to obtain a biomechanical dental model;

[0044] Simulation module: Used to perform time-progressive iteration on the biomechanical dental model through finite element analysis to obtain four-dimensional dynamic simulation data simulating the tooth movement process, so as to provide a visual orthodontic teaching demonstration based on the four-dimensional dynamic simulation data.

[0045] This invention provides a dynamic simulation method and system for tooth movement based on the Typodont model. By constructing a high-precision three-dimensional dental model using digital technology, it overcomes the limitations of traditional Typodont physical models, significantly improving the efficiency and quality of teaching and training. Compared to the cumbersome process of repeated heating and cooling required by traditional models, this method can instantly demonstrate the application effect of orthodontic appliances, greatly shortening the training cycle and improving learning efficiency. Secondly, this invention introduces a simulation system based on real biomechanical parameters. By accurately assigning material property values ​​to tissues such as teeth, periodontal ligament, and alveolar bone, a simulation platform that more closely resembles the real oral environment is constructed, bridging the significant gap between the thermoplasticity of traditional wax embankments and the physiological reconstruction of real alveolar bone, making the simulation results more clinically valuable. Thirdly, this invention achieves four-dimensional dynamic simulation of the tooth movement process through finite element analysis. This invention not only allows for the observation of static results at different time points but also dynamically displays the continuous changes in tooth movement throughout the entire treatment process. This full-process visualization significantly enhances learners' understanding of orthodontic biomechanics principles, contributing to the formation of a systematic diagnostic and treatment mindset. Furthermore, this invention accurately simulates the complex intraoral environment, including factors such as occlusal force, gingival elasticity, and periodontal ligament fibers. This enables learners to comprehensively consider the impact of various biomechanical factors on treatment outcomes, avoiding cognitive biases caused by the oversimplification of traditional models. The invention also establishes a real-time biofeedback mechanism, allowing learners to intuitively monitor changes in orthodontic force. This helps to precisely control the magnitude and direction of force application, preventing the formation of bad operating habits such as excessive force application, and reducing the risk of complications such as root resorption and bone fenestration in clinical practice. This makes the simulation results more accurate and reliable, providing an objective and quantitative basis for teaching evaluation.

[0046] This invention standardizes and normalizes the teaching process through digital technology, providing a unified operational standard and evaluation system for orthodontic teaching, greatly promoting the overall improvement of teaching quality, and providing a safe and efficient skills training platform for orthodontic beginners, shortening the clinical learning curve, and laying a solid foundation for orthodontic professional teaching. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0048] Figure 1 A schematic diagram of a dynamic simulation method for tooth movement based on the Typodont model provided by this invention;

[0049] Figure 2 This is a schematic diagram of a dynamic simulation system for tooth movement based on the Typodont model, provided by the present invention. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, embodiments of this invention, and should not be construed as limiting the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. In the description of this invention, it should be understood that the terminology used is for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0051] To better understand this invention, the research background of this invention will be explained in detail below.

[0052] Orthodontics is a discipline that combines theoretical depth with practical application. Its core lies in achieving functional reconstruction of the dentition system through precise biomechanical control and dynamically optimizing the treatment process based on real-time biofeedback mechanisms. Fixed orthodontic treatment is the most common orthodontic method. In fixed orthodontics, the bracket bonding position and the shape and angle of the archwire directly determine the tooth movement trajectory.

[0053] However, because fixed orthodontic appliances generate a complex force system after activation, the movement path of teeth is difficult to predict accurately. Especially for inexperienced doctors, the long-term clinical operation effect is difficult to grasp. Improper operation may also lead to unwanted tooth movement, or even increase the risk of root resorption, bone fenestration, bone fracture, etc.

[0054] To help orthodontic beginners intuitively understand the principles of orthodontic mechanics and improve operational precision, traditional Typodont training involves bonding brackets and placing archwires on a model, and using a water bath to heat the wax model to simulate tooth movement under the action of the elastic archwire. This provides medical students with preclinical skills training, thereby improving their understanding of biomechanics and the accuracy of their operations.

[0055] Typodont models are important tools for orthodontic teaching. Composed of resin teeth, wax embankments, and a fixed base, they simulate the structure of the dentition system, providing a highly realistic operating environment for preclinical skills training. The teaching process includes three stages: First, installing the appliances, such as bracket bonding and archwire insertion; second, placing the model in a temperature-controlled water bath to soften the wax embankment, simulating the plasticity of alveolar bone and allowing tooth movement; and finally, observing tooth displacement after cooling and fixing the model.

[0056] Typodont offers several teaching advantages: it provides a simulated operating environment that highly replicates clinical orthodontic procedures, allowing students to practice basic skills such as bracket bonding and archwire bending without patient pressure, thus reducing the risks of clinical training; it can simulate special cases such as tooth extraction gap closure and arch expansion treatment, helping students develop a systematic diagnostic and treatment mindset.

[0057] However, traditional Typodont therapy still has limitations: the operation process is lengthy, limiting the training cycle; the material properties differ from real tissue, and the thermoplasticity of the wax rim cannot accurately simulate the physiological remodeling of alveolar bone, simplifying the tooth movement process and ignoring biofeedback such as muscle strength and cortical bone anchorage; it cannot simulate the real intraoral environment (occlusal force, gingival and periodontal ligament fibers, etc.), making it difficult to reflect the actual biomechanical response in clinical practice; it lacks a dynamic feedback mechanism, making it difficult for students to monitor changes in orthodontic force in real time, making it difficult to accurately control the force application, and even leading to incorrect habits such as over-applying force; there are no unified standards for parameters such as heating time and force application method, and if guidance is insufficient, it is easy for students to operate mechanically and ignore the consideration of biomechanical principles.

[0058] Existing research combines 3D scanning and reverse engineering techniques to digitize Typodont before and after the experiment, and then overlays matching tooth models in software to create a 3D model of the dentition with roots. Subsequently, using the model's rigid base as a reference, the initial and final models are overlaid in Geomagic software, and the displacement of each landmark point is marked and measured to quantitatively analyze the 3D movement of the teeth, thus providing a reference for clinical applications. However, this method still has limitations; it can only present static results at two time points, failing to reflect the dynamic changes of teeth during orthodontic treatment, and also unable to simulate the real intraoral environment such as the periodontal ligament.

[0059] Therefore, this invention proposes a dynamic simulation method and system for tooth movement based on the Typodont model.

[0060] The embodiments of the present invention are described below with reference to the accompanying drawings.

[0061] In this embodiment, the present invention provides a dynamic simulation method and system for tooth movement based on the Typodont model, which is used for teaching and training in orthodontics and provides students and doctors with a visual teaching demonstration of the orthodontic treatment process.

[0062] It should be noted that the dynamic simulation method and system for tooth movement based on the Typodont model described in this invention is not limited to a specific application field. This method, through the establishment of an accurate three-dimensional digital dental model and biomechanical simulation, can realistically reproduce the dynamic process of tooth movement, and has broad application value. It can be applied to teaching and training in orthodontics, providing medical students and clinicians with an intuitive visual teaching tool. It can also be used in multiple fields such as predicting and optimizing clinical treatment plans, designing and validating orthodontic instruments, and analyzing data from scientific research experiments. The technical means of this invention are universal and should not be construed as limited to teaching purposes; its application scope covers, but is not limited to, various aspects such as medical education, clinical practice, scientific research, and related industrial design.

[0063] like Figure 1 As shown, this invention provides a dynamic simulation method for tooth movement based on the Typodont model, comprising:

[0064] S1: Data is collected from artificial teeth and fixed orthodontic appliances through 3D scanning to obtain 3D data of the dental and jaw structure.

[0065] In step S1, the three-dimensional data is acquired using either a first acquisition method or a second acquisition method.

[0066] Furthermore, in step S1 of the present invention, data is first collected from the artificial teeth and fixed orthodontic appliances using three-dimensional scanning technology to obtain three-dimensional data of the dental and jaw structure. This can be achieved through two acquisition methods: a first acquisition method and a second acquisition method. The first acquisition method is suitable for a standardized laboratory environment and involves directly scanning the artificial tooth model. The second acquisition method is based on clinical patient data and obtains real oral structure information through medical imaging techniques.

[0067] The first acquisition method further includes:

[0068] S111: The artificial tooth is scanned using a 3D scanner to obtain an STL model of the tooth.

[0069] Furthermore, the STL (Stereolithography) model is a triangular mesh model that represents the shape of an object's surface by piecing together triangles. In the specific scanning process, the 3D scanner emits structured light or laser light, and the CCD sensor receives the reflected signals to calculate the 3D coordinate point cloud data of the object's surface. The obtained point cloud data is processed by noise reduction, filtering, and mesh reconstruction to be converted into a triangular mesh model with a clear topological structure. Finally, a high-precision STL model composed of multiple triangular patches after mesh reconstruction is obtained. Each triangular patch is defined by three vertex coordinates and one normal vector, accurately describing the geometric shape of the tooth surface.

[0070] S112: The artificial tooth is placed in a standard occlusal wax rim and a full dentition scan is performed to obtain three-dimensional data of the complete dentition.

[0071] Furthermore, the standard occlusal wax ridge is the basic structure simulating the alveolar bone and occlusal relationship. It is made of special silicone rubber or wax material. The principle of full dentition scanning is the same as that of single-tooth scanning, but it requires a larger scanning range and more complex data stitching. The scanning system uses a feature point matching algorithm to spatially register multiple scan data to generate a complete dentition model in a unified coordinate system. During the process, the precise positional relationship of each tooth and the overall morphological characteristics of the dentition are recorded, providing a basic data framework for subsequent simulations.

[0072] S113: Obtain three-dimensional structural data of fixed orthodontic appliances by collecting original digital files of different types of brackets and archwires.

[0073] In step S113, three-dimensional structural data of the fixed orthodontic appliance is obtained by collecting original digital files of different types of brackets and archwires. Orthodontic brackets include various types such as straight wire brackets and square wire brackets. Archwires have different materials and cross-sectional dimensions. The three-dimensional data of these orthodontic appliances can be collected by a high-precision industrial-grade scanner. The collected data contains the precise geometric parameters of the orthodontic appliance, such as key parameters such as bracket groove size, incident angle, and torsion angle.

[0074] The second acquisition method further includes:

[0075] S121: Scanning the subject using cone-beam computed tomography (CBCT) to obtain raw tomographic data containing information about soft and hard tissues.

[0076] Cone-beam computed tomography (CBCT) is a specialized CT scanning technique that uses a cone-shaped X-ray beam and a two-dimensional detector array to acquire complete three-dimensional data of the patient's head in a single rotation. During a CBCT scan, the X-ray source and detectors rotate approximately 180-360 degrees around the patient's head, acquiring hundreds of two-dimensional projection images.

[0077] The original projection data is then reconstructed into voxel data using a back-projection algorithm, with each voxel representing the tissue density value within a tiny cube in space. The advantage of CBCT scans lies in their low radiation dose and ability to simultaneously acquire three-dimensional information of hard tissues such as teeth and alveolar bone, providing complete anatomical structural data for subsequent modeling. Specifically, the contours of teeth and bones can be extracted through grayscale thresholding.

[0078] S122: Scan the subject's dentition using an intraoral scanner to obtain surface information of a digital dental model.

[0079] Intraoral scanners can perform three-dimensional scanning directly inside a patient's mouth. During the scan, the operator places the scanning head inside the patient's mouth and moves it slowly along the dental arch. The scanning system collects and stitches three-dimensional data in real time. The collected data is processed by an automatic registration algorithm to form a complete model of the upper and lower jaw dental arches and a record of occlusal relationships. The final surface information has a higher surface detail resolution and can accurately reflect the crown morphology and occlusal contact relationship.

[0080] S123: Using a 3D scanner, different specifications of orthodontic appliances are scanned to obtain 3D data including straight wire brackets, square wire brackets, and archwires of different sizes.

[0081] The three-dimensional data collected in step S123 of this invention is similar to that of the first acquisition method, with the aim of obtaining accurate geometric data of the orthodontic appliance to provide a basis for subsequent mechanical simulation. The difference is that the second acquisition method requires scanning a specific model of orthodontic appliance that matches the clinical treatment to ensure the consistency between the simulation results and the actual treatment effect.

[0082] S2: Based on the three-dimensional data, perform overlap analysis on the crown root model to obtain a digital dental model containing periodontal tissues.

[0083] Step S2 further includes:

[0084] S21: Using Geomagic software, tooth models at different stages are aligned at the crown to obtain the three-dimensional spatial relationship of the crown.

[0085] In step S21, the 3D crown data obtained in step S1 is first imported into the reverse engineering software Geomagic. Automatic coarse registration is performed using the Global Best-Fit Registration algorithm, followed by fine registration using the Iterative Closest Point (ICP) algorithm. The core principle of the ICP algorithm is to iteratively find the optimal rigid body transformation between two point cloud datasets, minimizing the sum of squared Euclidean distances between them. In each iteration, the algorithm first finds the point correspondence between the two point clouds, then calculates the optimal rigid body transformation, updates the position of the source point cloud, and repeats this process until convergence. Alignment accuracy is measured using the root mean square error (RMSE).

[0086] It should be noted that the names of commercial software such as Geomagic mentioned in the embodiments of this invention are merely illustrative examples of technical implementation solutions and do not constitute a limitation on the technical solutions of this invention, nor do they involve any copyright issues. The core technology of this invention lies in the dynamic simulation method for tooth movement based on the Typodont model itself, rather than the use of specific software tools.

[0087] In practice, those skilled in the art can choose other equivalent reverse engineering software or 3D modeling software to achieve the same technical effect according to specific needs, such as other products from 3D Systems, open-source software MeshLab and CloudCompare, or self-developed dedicated software. Therefore, the technical solution described in this invention is universal and portable, does not depend on any specific commercial software, and the choice of software tools should not be construed as a limitation on the scope of protection of this invention.

[0088] S22: Establish the spatial position of the tooth root structure based on the three-dimensional spatial positional relationship to obtain the tooth model.

[0089] Since intraoral scanning or conventional dental model scanning cannot obtain root information, this invention integrates root information from CBCT data with crown scanning data in step S22. Specifically, a feature-point-based registration method is used. First, the complete tooth structure (including crown and root) is segmented from the CBCT data. Then, using the crown portion as a reference area, the crown in the CBCT is registered with the previously aligned high-precision crown scanning data using feature points. Registration uses a matching algorithm based on surface curvature and anatomical feature points. Through the spatial correspondence of anatomical landmarks such as the cervical line, the highest point of the crown margin, the cusp, and the pits and fissures, the transformation matrix between the two sets of data is calculated, transforming the root data in the CBCT to a unified coordinate system. Because the resolution of CBCT data is lower than that of intraoral scanning data, step S22 also includes data fusion of the crown transition area. Specifically, this invention uses B-spline interpolation to smooth the data splicing boundary in the cervical region, ensuring the continuity and realism of the crown-root transition.

[0090] S23: Add periodontal tissue structure data to the tooth model to obtain a digital dental model including the periodontal ligament, gingiva, and maxilla and mandible.

[0091] Furthermore, in the obtained digital dental model, the periodontal ligament is a fibrous tissue connecting the teeth and alveolar bone, with a width of approximately 0.25 mm. The gingiva is a mucosal tissue covering the surface of the alveolar bone, and the maxilla and mandible are bony structures supporting the teeth. The model construction of these tissues is based on CBCT data segmentation and anatomical rules.

[0092] Specifically, bone tissue structures are first extracted from CBCT data using threshold segmentation. Region growing algorithms and morphological operations are then used to optimize the segmentation results, obtaining three-dimensional models of the maxilla and mandible. For the periodontal ligament, since its thickness is lower than the resolution of CBCT, a computer-aided design method is employed. A uniformly thick periodontal ligament model is created by offsetting the root surface by 0.25 mm. The offset operation uses a normal vector extrapolation algorithm, extrapolating a specified distance along the normal vector direction of each vertex on the root surface to generate a new surface model. For the gingival tissue, a gingival model is constructed using a surface reconstruction algorithm, combining the soft tissue contours and anatomical rules from CBCT, ensuring a natural transition with the crown and alveolar bone. During data processing, the Laplacian smoothing algorithm is used to optimize all tissue surfaces, reducing noise and maintaining the realism of the anatomical structure. Laplacian smoothing is an iterative smoothing algorithm based on mesh topology that achieves surface smoothing by moving each vertex towards the geometric center of its adjacent vertices while preserving the overall shape.

[0093] S3: Assign material properties to the anatomical structures in the digital dental model according to preset material parameters to obtain a biomechanical dental model.

[0094] Specifically, step S3 includes:

[0095] Linear elasticity and isotropic material properties were assigned to alveolar bone and teeth to obtain the first mechanical property model of hard tissue; homogeneous material properties were assigned to gingiva and periodontal ligament to obtain the second mechanical property model of soft tissue; and material properties were assigned to brackets and archwires of different specifications to obtain the third mechanical property model of orthodontic appliances.

[0096] Specifically, the material property assignment of this invention is divided into three main parts: First, linear elasticity and isotropic material properties are assigned to alveolar bone and teeth to obtain the first mechanical property model of hard tissue. Linear elasticity means that the strain of the material is proportional to the stress within a certain stress range, and isotropicity means that the mechanical properties of the material are the same in all directions. Second, homogeneous material properties are assigned to gingiva and periodontal ligament to obtain the second mechanical property model of soft tissue. Homogeneous material refers to material with uniformly distributed physical properties on a macroscopic scale. Although the microstructure of soft tissue is complex, it can be simplified to homogeneous material treatment in mechanical simulation. Finally, material property values ​​are assigned to brackets and archwires of different specifications to obtain the third mechanical property model of orthodontic appliances.

[0097] Among them, the elastic modulus of the periodontal ligament is assigned a value of MPa, Poisson's ratio assigned a value of 0.45; elastic modulus of cortical bone assigned a value of MPa, Poisson's ratio assigned a value of 0.30; elastic modulus of cancellous bone assigned a value of MPa, Poisson's ratio assigned a value of 0.30; the elastic modulus of the tooth assigned a value of MPa, with a Poisson's ratio of 0.30.

[0098] Furthermore, the periodontal ligament, a connective tissue connecting the tooth root and alveolar bone, has an elastic modulus of 0.68 MPa and a Poisson's ratio of 0.45. A Poisson's ratio close to 0.5 indicates near-incompressibility, reflecting the characteristic that the periodontal ligament's volume remains almost unchanged under stress. The cortical bone is the dense outer layer of alveolar bone, with an elastic modulus of 13700 MPa and a Poisson's ratio of 0.30. The cancellous bone is the porous bone structure inside the alveolar bone, with an elastic modulus of 1370 MPa and a Poisson's ratio of 0.30. The elastic modulus of the tooth body is 20300 MPa, and the Poisson's ratio is 0.30. After the parameters are assigned, the data processing system enters these material parameters into the material library of the finite element analysis software, forming a material parameter matrix. The specific material parameters of each tissue are shown in Table 1.

[0099] Table 1. Material parameters of each microstructure in the material property assignment.

[0100]

[0101] S4: The biomechanical dental model is iteratively analyzed over time using finite element analysis to obtain four-dimensional dynamic simulation data simulating the tooth movement process, and a visual orthodontic teaching demonstration is provided based on the four-dimensional dynamic simulation data.

[0102] The finite element analysis described above is a numerical calculation method that discretizes a complex physical system into a finite number of elements for analysis. Specifically, in the digital Typodont system of this invention, time-recursive iteration refers to the step-by-step calculation of the changes in various physical parameters during tooth movement in the time dimension. The purpose is to combine the three-dimensional spatial model with the time dimension to form a four-dimensional dynamic simulation, making the orthodontic treatment process visible. The final four-dimensional dynamic simulation data contains a complete set of information on the changes in spatial coordinates over time, recording the evolution of parameters such as tooth position and periodontal tissue stress distribution over time.

[0103] Step S4 further includes:

[0104] S41: Set the fixed constraints for the maxilla and mandible to obtain the model reference.

[0105] Furthermore, the fixed constraint condition refers to setting the degrees of freedom of a specific region to zero in the finite element analysis, so that these regions remain stationary during the calculation. For the maxilla and mandible, this invention selects the temporomandibular joint region and the skull base connection site as fixed points. Specifically, firstly, for each constrained node, its displacement vector is set to 0, thereby establishing a spatial reference coordinate system for the entire model. Subsequently, the constraint conditions are transformed into linear equations and added to the global stiffness matrix. The obtained model reference refers to the spatial reference system established through the fixed constraint conditions, providing a fixed reference for subsequent calculations of relative tooth displacements.

[0106] S42: By setting the fixed contact between the teeth and the bracket and the sliding contact with gap between the bracket and the archwire, the force transmission mechanism of the model is obtained.

[0107] Contact conditions define the interaction between different components in finite element analysis. Fixed contact means that the two surfaces are completely bonded together, which is achieved in numerical calculations through shared nodes or multi-point constraint equations. In this invention, when setting fixed contact between teeth and brackets, the corresponding nodes of the two surfaces are rigidly connected by a program setting, so that they move as a whole. Frictional contact with gap is more complex, allowing relative movement between the bracket and archwire, but preventing them from penetrating each other.

[0108] During the calculation, a contact detection algorithm is used to continuously search for potential contact point pairs. Contact constraints are applied by the penalty function method, which simulates contact stiffness by adding virtual springs to improve numerical stability. The model force transmission mechanism refers to the mechanical transmission path constructed through these contact conditions. Orthodontic force is transmitted from the archwire to the bracket, then from the bracket to the tooth, and finally acts on the periodontal tissue.

[0109] S43: By simulating the process of the archwire recovering from its initial bent state to a straight state, load distribution data on multiple parts of the dental arch are obtained.

[0110] Furthermore, the simulation of the archwire recovering from its initial curved state to a straight state in step S43 is the core calculation for realizing the orthodontic force generation. At the data processing level, the initial shape of the archwire (a curved state inconsistent with the tooth alignment) and the target shape (an ideal straight state) are first defined. Then, the deformation process between the initial shape and the target shape is discretized into multiple calculation substeps, and the elastic restoring force of the archwire is solved in each substep.

[0111] Specifically, in the process of calculating the load distribution data of multiple parts of the dentition, the present invention tracks the displacement and stress state of each node of the archwire by setting a program, and calculates the force and torque acting on the bracket by using a contact algorithm. The final load distribution data is a complete mechanical state description, including the three-dimensional force vector and torque vector of each tooth position. The obtained data records the distribution of orthodontic force in the entire dentition.

[0112] S44: Establish a dynamic simulation model based on the model reference, the model force transmission mechanism, and the load distribution data.

[0113] Dynamic simulation models serve as a bridge between static mechanical analysis and time evolution. The process of establishing such models involves transforming the previously calculated stress state into a dynamic process that changes over time. It should be noted that the model of this invention incorporates a biofeedback mechanism, demonstrating how periodontal tissues respond to mechanical stimuli.

[0114] Step S44 further includes:

[0115] S441: Orthodontic force is applied by elastic deformation of the archwire and the initial displacement of the tooth under stress is calculated to obtain tooth movement data.

[0116] Furthermore, in step S441, based on the load distribution data calculated in step S43, the corresponding forces and moments are first applied to the tooth model. Then, a global stiffness matrix and nodal force vectors are constructed, and the displacement vector is obtained by solving the linear equation system. During the calculation, the nonlinear characteristics of the periodontal ligament need to be considered, and its mechanical behavior is described by a piecewise linear approximation or a hyperelastic model. The final tooth movement data includes the translational displacement vector and rotation angle vector of each tooth position, which describes the instantaneous response of the tooth under the action of the initial orthodontic force.

[0117] S442: Update the alveolar bone geometry based on the tooth movement data to obtain simulation results of bone resorption and reconstruction.

[0118] Bone remodeling is a key biological process in orthodontic treatment, determining the long-term behavior of tooth movement. Specifically, step S442 first calculates the stress distribution of the periodontal ligament after tooth movement, quantifying mechanical stimulation using the strain energy density method or principal stress method. Then, based on Frost's mechanical adaptability theory, the periodontal ligament stress value is substituted into the bone remodeling rate equation: that is, bone resorption is triggered when compressive stress exceeds a threshold, and bone formation is promoted when tensile stress exceeds a threshold. Subsequently, the geometry is updated by modifying the coordinates of the mesh nodes. In the compression region, the nodes on the bone surface are moved inward (simulating bone resorption), and in the tension region, the nodes are moved outward (simulating bone formation). The amount of movement is proportional to the stress magnitude and the time step. The final simulation result of bone resorption and reconstruction is an updated alveolar bone mesh model, reflecting the morphological changes of bone tissue over a specific time period.

[0119] S443: By maintaining a constant periodontal ligament space, the periodontal ligament geometry is adjusted synchronously to obtain an updated simulation model.

[0120] In step S443, the updated positions of the root surface and bone surface are first determined, and then the periodontal ligament geometric model is reconstructed. The specific algorithm is to calculate the normal vector of each node on the root surface, extend it along the direction by a predetermined distance to determine the corresponding point on the outer surface of the periodontal ligament. For complex areas (such as root bifurcation), local coordinate transformation and interpolation algorithms are used to ensure uniform periodontal ligament thickness. The updated periodontal ligament model needs to be re-meshed and the element quality needs to meet the numerical calculation requirements. The final updated simulation model includes the moved tooth position, the reshaped alveolar bone morphology, and the reconstructed periodontal ligament structure, providing initial conditions for the next round of iterative calculation.

[0121] S444: Iteratively update the simulation model to obtain a dynamic simulation model.

[0122] In step S444, the entire iterative process is managed by setting loop control parameters (such as total number of iterations, convergence conditions, etc.). Each iteration uses the output of the previous step as the input condition for the next step, forming a closed-loop feedback system. In each loop, a complete mechanical analysis-biological response-geometric update process must be executed. The dynamic model obtained after the update can save the complete model state at each key time point, including geometric information, mechanical parameters and displacement data, which can reflect the entire time evolution process of tooth movement.

[0123] S45: Simulate the tooth to be simulated using the dynamic simulation model, and output four-dimensional dynamic simulation data simulating the tooth movement process.

[0124] The output four-dimensional dynamic simulation data is a multidimensional dataset containing complete information on spatial three-dimensional coordinates and the time dimension. The specific data structure includes: time series geometry file (recording the grid coordinates of each time step), mechanical parameter file (recording the stress-strain distribution), displacement file (recording the tooth movement trajectory), and biological response file (recording the amount of bone remodeling). The four-dimensional dynamic simulation data not only shows the final results, but also reveals the changes in mechanical state throughout the process.

[0125] like Figure 2 As shown, the present invention also provides a dynamic simulation system for tooth movement based on the Typodont model, comprising:

[0126] Scanning module 100: Used to acquire data on artificial teeth and fixed orthodontic appliances through three-dimensional scanning, and obtain three-dimensional data of the dental and jaw structure;

[0127] Analysis module 200: used to perform overlap analysis on the crown root model based on the three-dimensional data to obtain a digital dental model containing periodontal tissues;

[0128] Assignment module 300: used to assign material properties to the anatomical structures in the digital dental model according to preset material parameters, so as to obtain a biomechanical dental model;

[0129] Simulation module 400: Used to perform time-recursive iteration on the biomechanical dental model through finite element analysis to obtain four-dimensional dynamic simulation data simulating the tooth movement process, so as to provide a visual orthodontic teaching demonstration based on the four-dimensional dynamic simulation data.

[0130] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0131] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0132] This invention develops a digital Typodont system based on high-precision three-dimensional dental models constructed from intraoral scan data. This system enables dynamic visualization simulation and intelligent scoring of the tooth movement process, covering virtual bracket positioning, archwire design, dynamic visualization simulation of tooth movement, and simulation of complex intraoral conditions (such as periodontal conditions and occlusal forces). This improves teaching interactivity and operational standardization, assists in teaching and skills training for orthodontic beginners, and overcomes the limitations of traditional Typodont systems, such as delayed feedback and difficulty in quantification.

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dynamic simulation method for tooth movement based on the Typodont model, characterized in that, include: S1: Data acquisition of artificial teeth and fixed orthodontic appliances through 3D scanning to obtain 3D data of the dental and jaw structure; S2: Based on the three-dimensional data, perform overlap analysis on the crown root model to obtain a digital dental model containing periodontal tissues; Step S2 further includes: S21: Aligning tooth models at different stages on the crown using Geomagic software to obtain the three-dimensional spatial positional relationship of the crown; S22: Establishing the spatial position of the root structure based on the three-dimensional spatial positional relationship to obtain a tooth model; S23: Adding periodontal tissue structure data to the tooth model to obtain a digital dental model including the periodontal ligament, gingiva, and maxilla and mandible. S3: Assign material properties to the anatomical structures in the digital dental model according to preset material parameters to obtain a biomechanical dental model; S4: The biomechanical dental model is iteratively analyzed over time using finite element analysis to obtain four-dimensional dynamic simulation data simulating the tooth movement process, and a visual orthodontic teaching demonstration is provided based on the four-dimensional dynamic simulation data.

2. The dynamic simulation method for tooth movement based on the Typodont model according to claim 1, characterized in that, The three-dimensional data in step S1 is acquired using either the first acquisition method or the second acquisition method.

3. The dynamic simulation method for tooth movement based on the Typodont model according to claim 2, characterized in that, The first acquisition method further includes: S111: The artificial tooth is scanned using a 3D scanner to obtain an STL model of the tooth; S112: The artificial tooth is placed in a standard occlusal wax rim and a full dentition scan is performed to obtain three-dimensional data of the complete dentition. S113: Obtain three-dimensional structural data of fixed orthodontic appliances by collecting original digital files of different types of brackets and archwires.

4. The dynamic simulation method for tooth movement based on the Typodont model according to claim 2, characterized in that, The second acquisition method further includes: S121: Scanning the subject using cone-beam CT to obtain raw tomographic data containing information about soft and hard tissues; S122: Scan the subject's dentition using an intraoral scanner to obtain surface information of a digital dental model; S123: Using a 3D scanner, different specifications of orthodontic appliances are scanned to obtain 3D data including straight wire brackets, square wire brackets, and archwires of different sizes.

5. The dynamic simulation method for tooth movement based on the Typodont model according to claim 1, characterized in that, Step S3 specifically includes: Linear elastic and isotropic material properties were assigned to both alveolar bone and teeth to obtain the first mechanical property model of hard tissue; Homogeneous material properties were assigned to both the gingiva and periodontal ligament to obtain a second mechanical property model of the soft tissue. By assigning material property values ​​to brackets and archwires of different specifications, a third mechanical property model of the orthodontic appliance is obtained.

6. The dynamic simulation method for tooth movement based on the Typodont model according to claim 5, characterized in that, The elastic modulus of the periodontal ligament is assigned a value of MPa, Poisson's ratio assigned a value of 0.45; elastic modulus of cortical bone assigned a value of MPa, Poisson's ratio assigned a value of 0.30; elastic modulus of cancellous bone assigned a value of MPa, Poisson's ratio assigned a value of 0.30; the elastic modulus of the tooth assigned a value of MPa, with a Poisson's ratio of 0.

30.

7. The dynamic simulation method for tooth movement based on the Typodont model according to claim 1, characterized in that, Step S4 further includes: S41: Set the fixed constraints for the maxilla and mandible to obtain the model reference. S42: By setting the fixed contact between the teeth and the bracket and the sliding contact with gap between the bracket and the archwire, the force transmission mechanism of the model is obtained; S43: By simulating the process of the archwire recovering from its initial bent state to a straight state, load distribution data on multiple parts of the dental arch are obtained; S44: Establish a dynamic simulation model based on the model reference, the model force transmission mechanism, and the load distribution data; S45: Simulate the tooth to be simulated using the dynamic simulation model, and output four-dimensional dynamic simulation data simulating the tooth movement process.

8. The dynamic simulation method for tooth movement based on the Typodont model according to claim 7, characterized in that, Step S44 further includes: S441: Orthodontic force is applied by the elastic deformation of the archwire and the initial displacement of the tooth under stress is calculated to obtain tooth movement data; S442: Update the alveolar bone geometry based on the tooth movement data to obtain simulation results of bone resorption and reconstruction; S443: By maintaining a constant periodontal ligament space, the periodontal ligament geometry is adjusted synchronously to obtain an updated simulation model; S444: Iteratively update the simulation model to obtain a dynamic simulation model.

9. A dynamic simulation system for tooth movement based on the Typodont model, characterized in that, include: Scanning module: Used to acquire data on artificial teeth and fixed orthodontic appliances through 3D scanning, and obtain 3D data of the dental and jaw structure; Analysis module: used to perform overlap analysis on the crown root model based on the three-dimensional data to obtain a digital dental model containing periodontal tissues; The analysis module is further used to: align tooth models at different stages on the crown using Geomagic software to obtain the three-dimensional spatial positional relationship of the crown; establish the spatial position of the root structure based on the three-dimensional spatial positional relationship to obtain a tooth model; and add periodontal tissue structure data to the tooth model to obtain a digital dental model including the periodontal ligament, gingiva, and maxilla and mandible. Assignment module: used to assign material properties to the anatomical structures in the digital dental model according to preset material parameters, so as to obtain a biomechanical dental model; Simulation module: Used to perform time-progressive iteration on the biomechanical dental model through finite element analysis to obtain four-dimensional dynamic simulation data simulating the tooth movement process, so as to provide a visual orthodontic teaching demonstration based on the four-dimensional dynamic simulation data.

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