Orthodontic treatment plan design assistance method based on tooth movement digital twin
By constructing an individualized three-dimensional model of teeth, periodontal ligament, and alveolar bone, and assigning mechanical parameters based on patient characteristics, the orthodontic force and anchorage requirements are calculated. This solves the problems of insufficient dynamic updating and individualization of tooth movement models in existing technologies, and enables more accurate and predictable orthodontic treatment design.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TIANJIN DENTAL HOSPITAL
- Filing Date
- 2026-05-12
- Publication Date
- 2026-07-24
AI Technical Summary
Existing digital twin models of tooth movement lack dynamic update mechanisms, have insufficient individualized mechanical property assignments, and rely on experience for orthodontic treatment design, making it difficult to achieve accuracy and predictability.
A three-dimensional geometric model of the tooth-periodontal ligament-alveolar bone is constructed. Individualized mechanical parameters are assigned by combining the patient's age, periodontal biotype, and grayscale information. The orthodontic force vector and anchorage requirements are calculated through finite element analysis to form an individualized digital twin of tooth movement.
It improves the realism and individual adaptability of tooth movement simulation, ensures that the direction, magnitude and anchorage configuration of orthodontic forces have clear mechanical basis, and optimizes the accuracy and predictability of orthodontic plan design.
Smart Images
Figure CN122174583B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of orthodontic assistance technology, and in particular to an assistive method for designing orthodontic schemes based on a digital twin of tooth movement. Background Technology
[0002] With the development of digital oral medicine and computer-aided diagnosis and treatment technologies, orthodontics is gradually shifting from a traditional experience-driven model to a digital and model-assisted decision-making model. Early orthodontic plans relied primarily on doctors' judgment of tooth alignment and orthodontic forces based on two-dimensional imaging data, plaster models, and clinical experience, lacking quantitative analysis of the direction and magnitude of these forces. In recent years, the application of cone-beam computed tomography (CBCT) and intraoral scanning technologies has enabled the precise acquisition of the three-dimensional structures of teeth, roots, and alveolar bone, which is increasingly being combined with finite element analysis methods to study the stress distribution and displacement response of teeth and periodontal tissues under orthodontic forces. Building upon this foundation, digital twin technology has been introduced into the field of orthodontics. By digitally modeling and dynamically updating the individual patient's three-dimensional anatomical structure, biomechanical parameters, and changes in state during treatment, a digital twin of tooth movement is constructed that maintains a mapping relationship with the patient's actual oral condition. This allows for the prediction of tooth movement trends in a virtual environment and assists in orthodontic plan design, becoming an important development direction in current digital orthodontic research.
[0003] However, current technologies still have certain shortcomings in digital twin modeling of tooth movement and orthodontic biomechanical analysis. First, existing research largely focuses on building static 3D models or finite element analysis models based on image data. While these models can perform mechanical simulations, they often lack a dynamic update mechanism that continuously corresponds to the patient's actual treatment process, making it difficult to create a digital twin that reflects the entire process of tooth movement. Second, during model construction, the individualized mechanical properties of tissues such as teeth, periodontal ligaments, and alveolar bone are usually assigned uniform empirical parameters without fully incorporating information such as patient age, periodontal biotype, and alveolar bone grayscale distribution. This results in a limited degree of model reflection of real biomechanical behavior. Furthermore, current orthodontic treatment design typically employs a forward analysis approach, i.e., setting the orthodontic force first and then observing the tooth displacement results. It is difficult to directly solve for a reasonable orthodontic force system based on the target tooth position. Simultaneously, the design of the anchorage system still mainly relies on clinical experience and judgment, lacking quantitative analysis and decision-making support methods based on mechanical requirements, thus affecting the accuracy and predictability of orthodontic treatment design. Summary of the Invention
[0004] In view of the problems existing in existing methods for assisting the design of orthodontic plans based on digital twins of tooth movement, this invention is proposed. Therefore, the problem to be solved by this invention is how to provide an assisting method for designing orthodontic plans based on digital twins of tooth movement.
[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:
[0006] In a first aspect, the present invention provides an auxiliary method for designing orthodontic schemes based on a digital twin of tooth movement, which includes: acquiring cone-beam CT data of the patient's oral cavity and three-dimensional point cloud data of the crown surface, and constructing a three-dimensional geometric model of tooth-periodontal ligament-alveolar bone;
[0007] The three-dimensional geometric model is discretized into a finite element mesh. Based on the patient's age, periodontal biotype, and CT gray value, periodontal ligament viscoelastic parameters, alveolar bone gray-mechanical mapping parameters, and tooth linear elastic constants are assigned to form an individualized digital twin of tooth movement.
[0008] In a personalized digital twin of tooth movement, the target displacement vector is determined, the orthodontic force vector and anchorage requirement index are calculated, and the orthodontic treatment plan is designed based on the anchorage requirement index.
[0009] As a preferred embodiment of the orthodontic scheme design assistance method based on a digital twin of tooth movement described in this invention, the construction of the three-dimensional geometric model of tooth-periodontal ligament-alveolar bone includes:
[0010] Three-dimensional volume data containing teeth, periodontal ligament and alveolar bone tissue were obtained by intraoral cone-beam CT scanning, and three-dimensional point cloud data of the crown surface were obtained by intraoral scanning and reconstructed into a three-dimensional crown surface model.
[0011] The three-dimensional surface model of the tooth crown and the cone-beam CT data of the oral cavity are imported into the same spatial coordinate system. The spatial transformation matrix is calculated based on the corresponding anatomical structure to form fused data in a unified coordinate system.
[0012] The fused data is structurally segmented, and the alveolar bone region and tooth region are extracted based on the differences in CT grayscale distribution. The periodontal ligament region is constructed based on the spatial gap between the outer contour of the tooth root and the inner wall of the alveolar bone. Each region is converted into a three-dimensional surface boundary and integrated into a three-dimensional geometric model of tooth-periodontal ligament-alveolar bone.
[0013] As a preferred embodiment of the oral orthodontic scheme design assistance method based on the digital twin of tooth movement described in this invention, the discretization of the three-dimensional geometric model into a finite element mesh includes: spatially discretizing the tooth region, the periodontal ligament region, and the alveolar bone region respectively, so that each region forms a finite element mesh structure composed of nodes and elements, and a continuous node connection relationship is formed between the periodontal ligament elements, the tooth elements, and the alveolar bone elements.
[0014] As a preferred embodiment of the orthodontic scheme design assistance method based on a digital twin of tooth movement described in this invention, wherein: the formation of an individualized digital twin of tooth movement includes:
[0015] A three-dimensional geometric model after finite element mesh discretization is obtained, and a basic biomechanical model of the patient's oral cavity structure is established. The tooth structure is the main body of motion, the periodontal ligament is the mechanical transmission medium, and the alveolar bone is the supporting structure. A mechanical coupling system is formed through node connection relationship, which constitutes a virtual physical system describing the tooth movement process.
[0016] In the basic biomechanical model, the initial state space of the patient's oral structure is established. By spatially registering the tissue grayscale information in the oral cone-beam CT data with the surface morphology of the crown, a virtual mapping of the patient's oral structure is formed.
[0017] Define the structural state variables of tooth position state, periodontal ligament deformation state, and alveolar bone stress state. When the orthodontic force is applied to the tooth, the tooth displacement, periodontal ligament stress change and alveolar bone stress distribution are obtained by finite element solution. The results are recorded as new virtual physical system states in the model state library. The updated tooth position is used as the new calculation starting point to form a dynamic evolution model of the tooth movement process.
[0018] The CT grayscale value of each finite element in the alveolar bone region is extracted, and then converted into the element elastic modulus using a mapping function, as follows:
[0019]
[0020] in, This represents the elastic modulus of the alveolar bone finite element; Represents the CT grayscale value of a finite element element; This represents the mapping ratio coefficient from CT grayscale values to elastic modulus; This represents the basic elasticity correction factor;
[0021] Based on the patient's age and periodontal tissue condition, the viscoelastic parameters of the periodontal ligament unit are determined to ensure that the stress-strain relationship of the periodontal ligament satisfies the following:
[0022]
[0023] in, Indicates the periodontal ligament at any time The stress; Indicates the elastic modulus of the periodontal ligament; Indicates the periodontal ligament at any time The strain; Indicates the viscosity coefficient of the periodontal ligament;
[0024] Linear elastic mechanical parameters are assigned to the tooth unit so that the stress-strain relationship of the tooth satisfies:
[0025]
[0026] in, This represents the stress in a tooth element; This represents the elastic modulus of tooth tissue; Indicates the strain of the tooth element;
[0027] After assigning mechanical property values to all finite element units of the tooth, periodontal ligament, and alveolar bone, a personalized digital twin of tooth movement is formed.
[0028] As a preferred embodiment of the orthodontic scheme design assistance method based on a digital twin of tooth movement described in this invention, the calculation of the orthodontic force vector includes:
[0029] In the individualized digital twin of tooth movement, the initial position coordinate vector and the target position coordinate vector of the target tooth are defined, and the target displacement vector is determined, expressed as:
[0030]
[0031] in, Represents the target displacement vector; Represents the target position coordinate vector; Represents the initial position coordinate vector;
[0032] The target displacement vector is applied as a constraint to the finite element nodes of the tooth. The force-displacement relationship is established through the overall stiffness matrix of the finite element system. The orthodontic force vector acting on the tooth node is obtained by solving the problem. The orthodontic force vector is then mapped to the spatial position of the tooth crown to obtain the actual direction and point of application of the orthodontic force that can be applied.
[0033] As a preferred embodiment of the orthodontic scheme design assistance method based on a digital twin of tooth movement described in this invention, the step of assisting in orthodontic scheme design based on anchorage requirement indicators includes:
[0034] Based on the magnitude of the resultant force vector of the orthodontic force and the equivalent bearing area of the alveolar bone support region, the anchorage requirement index is calculated and expressed as:
[0035]
[0036] in, Indicates the demand index for support; This indicates the magnitude of the resultant force of the corrective force vector; This represents the equivalent load-bearing area of the alveolar bone support region;
[0037] Based on the anchorage demand index, the orthodontic force demand is mapped to the anchorage system design space. Candidate anchorage regions are identified in the individualized digital twin of tooth movement. Candidate anchorage regions include the crown region of adjacent teeth, the surface region of alveolar bone cortex, and the fixable region inside alveolar bone.
[0038] Based on the mechanical transmission process of the orthodontic force vector in the individualized digital twin of tooth movement, the concentration area and direction of the reaction force are determined, and the initial anchorage point is selected in the anchorage candidate area.
[0039] Simulation calculations of tooth movement were performed for different combinations of anchorage points to analyze the target tooth displacement path, adjacent tooth displacement, and alveolar bone stress distribution.
[0040] The final anchorage position is determined by adjusting the position of the anchorage point so that the target tooth moves along a predetermined path and the displacement and stress concentration of adjacent teeth are minimized.
[0041] The spatial coordinates of the final anchorage location are mapped to the anatomical location in the patient's actual oral cavity structure, and the type of anchorage device is determined based on the anatomical characteristics of the anchorage action area, including dental anchorage, micro-implant anchorage, or skeletal anchorage.
[0042] In a second aspect, the present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of an auxiliary method for designing orthodontic schemes based on a digital twin of tooth movement.
[0043] Thirdly, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, it implements the steps of an auxiliary method for designing orthodontic schemes based on a digital twin of tooth movement.
[0044] The beneficial effects of this invention are as follows: By constructing a complete three-dimensional structural model including teeth, periodontal ligament, and alveolar bone, and combining this model with patient age, periodontal biotype, and grayscale information to assign individualized mechanical parameters, a digital twin of tooth movement is established that can realistically reflect the mechanical response characteristics of periodontal tissues, thereby improving the realism and individual adaptability of tooth movement simulation. By solving for the orthodontic force vector and anchorage requirement index corresponding to the target displacement, the orthodontic force system design is directly driven by the target position, providing a clear mechanical basis for the direction, magnitude, and anchorage configuration of the orthodontic force. This effectively improves the accuracy, predictability, and personalization of orthodontic treatment plan design, reduces reliance on experience, and optimizes the overall treatment effect. Attached Figure Description
[0045] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0046] Figure 1 A flowchart illustrating an auxiliary method for designing orthodontic schemes based on digital twins of tooth movement. Detailed Implementation
[0047] To make the above-mentioned objects, features, and advantages of the present invention more readily understood, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.
[0048] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.
[0049] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.
[0050] Reference Figure 1 This is the first embodiment of the present invention, which provides an auxiliary method for designing orthodontic schemes based on a digital twin of tooth movement, including:
[0051] S1: Acquire cone-beam CT data of the patient's oral cavity and three-dimensional point cloud data of the crown surface to construct a three-dimensional geometric model of tooth-periodontal ligament-alveolar bone;
[0052] S2: Discretize the three-dimensional geometric model into a finite element mesh, and assign periodontal ligament viscoelastic parameters, alveolar bone gray-mechanical mapping parameters and tooth linear elastic constants according to the patient's age, periodontal biotype and CT gray value, respectively, to form an individualized digital twin of tooth movement;
[0053] S3: Determine the target displacement vector in the individualized digital twin of tooth movement, calculate the orthodontic force vector and anchorage requirement index, and assist in the design of orthodontic treatment plan based on the anchorage requirement index.
[0054] Specifically, patients undergo intraoral cone-beam computed tomography (CBCT) scans to acquire three-dimensional volumetric data including tooth structure, periodontal ligament space, and alveolar bone tissue, forming a voxel-based tomographic dataset of oral and maxillofacial structures. Each voxel in the dataset corresponds to a specific spatial coordinate and CT grayscale value, with the grayscale value reflecting the density information of the tissue at that location. Intraoral scans are performed on the same patient to acquire three-dimensional point cloud data of the crown surface morphology, and surface reconstruction is used to create a continuous three-dimensional surface model of the crown, ensuring a complete representation of the external geometric boundaries of the teeth.
[0055] Oral cone-beam CT data is imported into a 3D reconstruction environment. Voxel coordinate analysis is performed on the volume data to extract the spatial distribution range of the teeth, alveolar bone, and periodontal ligament regions. At the same time, the 3D surface model of the crown formed by intraoral scanning is imported into the same spatial coordinate system. Through initial spatial coordinate alignment, the 3D surface model of the crown and the oral cone-beam CT data are placed in a unified spatial reference frame. Then, based on the spatial positional relationship of the corresponding anatomical structure regions, the spatial transformation matrix is calculated to realize the mapping of the 3D surface model of the crown to the CT coordinate space, forming fused data under a unified coordinate system.
[0056] After spatial alignment, structural segmentation is performed on the fused image data. Based on the differences in grayscale distribution of different tissues in the CT images, the spatial range of the alveolar bone region is extracted to obtain the three-dimensional volume region of the alveolar bone. Based on the grayscale change boundary between the tooth tissue and the surrounding tissue, the complete volume structure region of the tooth root and crown is extracted. Based on the spatial gap region between the outer contour of the tooth root and the inner wall of the alveolar bone, the three-dimensional spatial region corresponding to the periodontal ligament is constructed, so that the tooth structure is wrapped by the periodontal ligament and embedded in the alveolar bone structure.
[0057] The extracted tooth region, periodontal ligament region, and alveolar bone region are converted into three-dimensional surface boundary representations and then subjected to surface continuum processing to form closed three-dimensional geometric boundaries for each structural region.
[0058] The three-dimensional geometric boundaries of each region are integrated into a unified spatial model to form a three-dimensional geometric model of tooth-periodontal ligament-alveolar bone, in which the tooth is located inside the periodontal ligament, the periodontal ligament covers the root of the tooth and is located in the internal space of the alveolar bone, and the alveolar bone serves as the outer supporting structure.
[0059] The constructed three-dimensional geometric model of tooth-periodontal ligament-alveolar bone is imported into the finite element discretization environment. The tooth structure region is spatially discretized, and the continuous geometric structure is divided into multiple spatial finite element elements, so that the tooth region forms a discrete mesh structure composed of nodes and elements.
[0060] The periodontal ligament region is spatially discretized to form a continuous finite element layer structure that surrounds the tooth root, and to ensure a continuous node connection between the periodontal ligament elements and the tooth elements.
[0061] Spatial discretization of the alveolar bone region enables the formation of a continuous three-dimensional finite element support structure in the alveolar bone region, and establishes a continuous connection with the outer side of the periodontal ligament.
[0062] After obtaining the three-dimensional geometric model of the teeth, periodontal ligament and alveolar bone and completing the finite element mesh discretization, a basic biomechanical model of the patient's oral structure is established. This model takes the tooth structure as the main body of motion, the periodontal ligament as the mechanical transmission medium, and the alveolar bone as the supporting structure. A mechanical coupling system is formed through node connection relationship, so that when the tooth is subjected to force, it can transmit the force to the alveolar bone through the periodontal ligament and generate corresponding stress and displacement response, thus constituting a virtual physical system describing the tooth movement process.
[0063] In the basic biomechanical model, the initial state space of the patient's oral structure is established. By spatially registering the tissue grayscale information in the oral cone-beam CT data with the morphology of the crown surface obtained by scanning, the tooth position, root morphology and alveolar bone structure in the virtual model are consistent with the patient's real oral structure, forming a virtual mapping of the patient's oral structure.
[0064] After initial mapping is completed, a dynamic state description mechanism for the tooth movement process is established. In the basic biomechanical model, multiple structural state variables such as tooth position state, periodontal ligament deformation state, and alveolar bone stress state are defined. When the orthodontic force is applied to the tooth, the tooth displacement, periodontal ligament stress change, and alveolar bone stress distribution are obtained through finite element solution. The results are recorded as new virtual physical system states in the model state library. Then, the updated tooth position is used as the new calculation starting point to form a dynamic evolution model of the tooth movement process.
[0065] After discretizing the finite element mesh, the CT grayscale value corresponding to each finite element in the alveolar bone region is extracted, and a mapping relationship between the CT grayscale value and the mechanical elastic modulus is established. The CT grayscale value is converted into the elastic modulus of the corresponding element through a mapping function, expressed as:
[0066]
[0067] in, This represents the elastic modulus of the alveolar bone finite element; Represents the CT grayscale value of a finite element element; This represents the mapping ratio coefficient from CT grayscale values to elastic modulus; This represents the basic elasticity correction coefficient.
[0068] Based on the patient's age and periodontal tissue structure, the viscoelastic parameters of the finite element units in the periodontal ligament region were determined to give the periodontal ligament units time-dependent mechanical response characteristics. The stress-strain relationship of the periodontal ligament is expressed as follows:
[0069]
[0070] in, Indicates the periodontal ligament at any time The stress; Indicates the elastic modulus of the periodontal ligament; Indicates the periodontal ligament at any time The strain; Indicates the viscosity coefficient of the periodontal ligament;
[0071] Linear elastic mechanical parameters are assigned to the finite element elements of the tooth region so that the stress-strain relationship of the tooth elements satisfies:
[0072]
[0073] in, This represents the stress in a tooth element; This represents the elastic modulus of tooth tissue; This represents the strain of a tooth unit.
[0074] A synchronous update mechanism is established between the virtual model and the patient's actual oral cavity condition. During orthodontic treatment, when the patient completes a phased follow-up examination and obtains new three-dimensional point cloud data of the crown surface, the new three-dimensional point cloud data of the crown surface is imported into the virtual model and spatially compared with the tooth position in the current virtual model. By analyzing the difference between the actual tooth position and the model's predicted position, the spatial position of the teeth, the periodontal tissue stress state, and related mechanical parameters in the virtual model are corrected and updated to form an individualized digital twin of tooth movement.
[0075] After completing the three-dimensional reconstruction of the patient's teeth, the spatial analysis of the patient's current dental arch structure is performed. By identifying key points on the crown of the teeth and calculating the spatial arrangement relationship between each tooth, the dental arch curve of the patient's current dental arch is established. The dental arch curve forms a continuous spatial curve by connecting the center positions of each tooth in the dental arch, which is used to describe the overall shape of the patient's current tooth arrangement.
[0076] Subsequently, the dental arch curves were matched and analyzed with the dental arch morphology in the standard normal dentition database. By comparing the curvature, length and left-right symmetry of the dental arch curves, the target dental arch curve that conforms to the normal occlusal relationship was determined. The target dental arch curve meets the structural requirements in terms of spatial morphology and serves as the spatial reference benchmark for the arrangement of the target dentition.
[0077] After the target dental arch curve is determined, the teeth that need to be moved are projected onto the target dental arch curve one by one. By calculating the closest spatial position between the center point of the tooth crown and the target dental arch curve, the arrangement position of the teeth on the target dental arch is determined. At the same time, the direction of the long axis of the teeth is determined according to the anatomical structure of the teeth, so that the teeth maintain a reasonable tilt angle and rotation angle in the target arrangement state.
[0078] Based on the target alignment, the key structural points of each tooth are extracted, including the crown center point, the reference point along the long axis of the tooth, and the root center point. The positions of the key points in the three-dimensional space are then vectorized. By using the crown center point as the representative of the tooth's spatial position and the long axis of the tooth as the representation of the tooth's orientation, a spatial position vector is constructed under the target tooth alignment. These spatial position vectors are then combined to form a set of target tooth position coordinate vectors.
[0079] In the individualized digital twin of tooth movement, the initial spatial position coordinate vector and the target spatial position coordinate vector of the target tooth are defined, and the target displacement vector is determined, expressed as:
[0080]
[0081] in, Represents the target displacement vector; Represents the target position coordinate vector; This represents the initial position coordinate vector.
[0082] The target displacement vector is applied as a constraint to the tooth finite element nodes. The relationship between force and displacement is established through the stiffness matrix of the finite element system, expressed as:
[0083]
[0084] in, This represents the vector of orthodontic force acting on the tooth node; The overall stiffness matrix represents the individualized tooth movement digital twin.
[0085] Obtain the orthodontic force vector required to produce the target displacement of the tooth, and map the calculated orthodontic force vector to the spatial position of the tooth crown to form the actual direction and point of application of the orthodontic force that can be applied.
[0086] Based on the magnitude and direction characteristics of the calculated corrective force vector, the anchorage requirement index of the corrective system is calculated and expressed as:
[0087]
[0088] in, Indicates the demand index for support; This indicates the magnitude of the resultant force of the corrective force vector; This indicates the equivalent load-bearing area of the alveolar bone support region.
[0089] Based on the anchorage requirement index, the orthodontic force requirement is mapped into the anchorage system design space, enabling the anchorage system to provide a reaction force consistent with the direction of the orthodontic force vector, maintain the overall system mechanical balance, and form a complete individualized orthodontic force system. This allows the target tooth to generate a predictable movement response in the individualized tooth movement digital twin according to the predetermined target displacement path, realizing the personalized design and assistance of orthodontic solutions.
[0090] The obtained orthodontic force vectors are loaded into a personalized digital twin of tooth movement, and the mechanical response of the teeth, periodontal ligament, and alveolar bone structures is simulated. This allows the orthodontic force to be transmitted along the tooth-periodontal ligament-alveolar bone path within the personalized digital twin of tooth movement, forming a reaction force distribution in the corresponding supporting structures. By analyzing the spatial distribution of the reaction force in the alveolar bone and adjacent tooth structures, the areas bearing the main reaction force and their spatial directions are determined, clarifying the source location and direction of the anchorage force.
[0091] In a digital twin of individualized tooth movement, a spatial representation of the anchorage system's action area is constructed. The action points of the anchorage system are limited to the surface area of the tooth crown, the surface area of the alveolar bone, and the fixable area inside the bone tissue. These areas are defined as the anchorage system design space. Based on the direction of the orthodontic force and the spatial distribution direction of the reaction force, an anchorage action direction consistent with the direction of the reaction force is established in the anchorage system design space. This enables the anchorage system to form a mechanical constraint relationship opposite to the direction of the orthodontic force, achieving an overall mechanical equilibrium state in the digital twin of individualized tooth movement.
[0092] After mapping the anchorage direction, the anchorage points are applied to the corresponding spatial region of the individualized digital twin of tooth movement. The tooth movement process is simulated again to observe the target tooth's movement path and the mechanical response of surrounding tissues. It is also analyzed whether adjacent teeth experience follow-up displacement and whether abnormal stress concentration occurs in the alveolar bone support area. Based on the simulation results, the anchorage points are gradually adjusted to spatial positions that effectively restrict the movement of non-target teeth and maintain the tooth's movement along the target path, thus creating a spatially stable constraint structure for the anchorage system.
[0093] When the anchorage system's position and direction of action can stably counteract the reaction effect of the orthodontic force, and the target tooth moves along the predetermined path while the surrounding structure remains stable, the anchorage position and direction of action are determined as the final anchorage system design result. This result is then mapped to the corresponding anatomical position in the actual oral space, completing the mapping process from orthodontic force requirements to the anchorage system design space, and achieving spatial matching between the anchorage system and the orthodontic force system.
[0094] Based on the three-dimensional geometric structure of the patient's teeth, alveolar bone and adjacent bone tissue, the anatomical areas in the oral cavity that can provide reaction force are identified and the areas are divided into different types of anchorage areas, including the crown structure area of adjacent teeth, the surface area of alveolar bone cortex and the fixable area inside alveolar bone. Spatial marking is performed in the individualized digital twin of tooth movement to form a candidate design space for the anchorage system.
[0095] After obtaining the anchorage requirement index, the orthodontic force vector is spatially analyzed in the individualized digital twin of tooth movement to determine the point of application, direction of application, and transmission path of reaction force. By analyzing the mechanical transmission process of orthodontic force in the tooth-periodontal ligament-alveolar bone structure, the main reaction force concentration area and reaction force direction are determined, and the reaction force direction is projected onto the anchorage candidate area to form the corresponding anchorage action direction in the anchorage design space.
[0096] Based on the reaction force transmission path, multiple spatial locations are selected as initial anchorage points within the anchorage candidate area near the reaction force path. Anchorage constraints opposite to the orthodontic force direction are applied in the individualized tooth movement digital twin, so that the anchorage points form different anchorage configuration schemes.
[0097] For each anchorage configuration scheme, the tooth movement process is simulated and calculated to analyze the displacement path of the target tooth, the displacement of adjacent teeth, and the stress distribution of the alveolar bone.
[0098] During the simulation, the positions of the anchorage points are continuously adjusted to ensure that the reaction force can be stably absorbed and the impact on non-target teeth is reduced. When a combination of anchorage points can make the target tooth move along a predetermined path, while the displacement of adjacent teeth remains within a small range and no obvious stress concentration occurs in the alveolar bone, the anchorage point position is determined as the effective anchorage position. If a single anchorage point cannot provide sufficient constraint, new anchorage points are added in the adjacent area and the simulation calculation is repeated until a stable anchorage configuration is formed.
[0099] After determining a stable anchorage location, the spatial coordinates of the anchorage location in the individualized digital twin of tooth movement are mapped to the corresponding anatomical location in the patient's real oral structure. The type of anchorage device is determined by combining the anatomical features of the anchorage action area. When the anchorage location is located in the crown area of an adjacent tooth, it is determined to be a dental anchorage structure. When the anchorage location is located on the surface of the alveolar cortex or in a stable area within the bone, it is mapped to a micro-implant anchorage or a bone anchorage structure, thus completing the spatial mapping of the anchorage system design.
[0100] This embodiment also provides a computer device applicable to the design assistance method for orthodontic schemes based on a digital twin of tooth movement, comprising: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement all or part of the steps of the method described in the above embodiments of the present invention.
[0101] This embodiment also provides a storage medium storing a computer program thereon. When the computer program is executed by a processor, it performs the method in any optional implementation of the above embodiments. The storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.
[0102] The storage medium proposed in this embodiment and the data storage method proposed in the above embodiments belong to the same inventive concept. Technical details not described in detail in this embodiment can be found in the above embodiments, and this embodiment has the same beneficial effects as the above embodiments.
[0103] In summary, this invention constructs a complete three-dimensional structural model including teeth, periodontal ligament, and alveolar bone, and assigns individualized mechanical parameters based on patient age, periodontal biotype, and grayscale information. This establishes a digital twin of tooth movement that realistically reflects the mechanical response characteristics of periodontal tissues, improving the realism and individual adaptability of tooth movement simulation. By solving for the orthodontic force vector and anchorage requirement index corresponding to the target displacement, the orthodontic force system design is directly driven by the target location. This provides a clear mechanical basis for the direction, magnitude, and anchorage configuration of the orthodontic force, effectively improving the accuracy, predictability, and personalization of orthodontic treatment design, reducing reliance on experience, and optimizing overall treatment outcomes.
[0104] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A method for assisting in the design of orthodontic schemes based on digital twins of tooth movement, characterized in that: include: Acquire cone-beam CT data of the patient's oral cavity and three-dimensional point cloud data of the tooth crown surface to construct a three-dimensional geometric model of tooth-periodontal ligament-alveolar bone; The three-dimensional geometric model is discretized into a finite element mesh. Based on the patient's age, periodontal tissue status, and CT grayscale value, periodontal ligament viscoelastic parameters, alveolar bone grayscale-mechanical mapping parameters, and tooth linear elastic mechanical parameters are assigned to form an individualized digital twin of tooth movement. In a personalized digital twin of tooth movement, the target displacement vector is determined, the orthodontic force vector and anchorage requirement index are calculated, and the orthodontic treatment plan is designed based on the anchorage requirement index. The design of orthodontic protocols based on anchorage requirements includes: Based on the magnitude of the resultant force vector of the orthodontic force and the equivalent bearing area of the alveolar bone support region, the anchorage requirement index is calculated and expressed as: in, Indicates the demand index for support; This indicates the magnitude of the resultant force of the corrective force vector; This represents the equivalent load-bearing area of the alveolar bone support region; Based on the anchorage demand index, the orthodontic force demand is mapped to the anchorage system design space. Candidate anchorage regions are identified in the individualized digital twin of tooth movement. Candidate anchorage regions include the crown region of adjacent teeth, the surface region of alveolar bone cortex, and the fixable region inside alveolar bone. Based on the mechanical transmission process of the orthodontic force vector in the individualized digital twin of tooth movement, the concentration area and direction of the reaction force are determined, and the initial anchorage point is selected in the anchorage candidate area. Simulation calculations of tooth movement were performed for different combinations of initial anchorage points to analyze the target tooth displacement path, adjacent tooth displacement, and alveolar bone stress distribution. The final anchorage position is determined by adjusting the position of the anchorage point so that the target tooth moves along a predetermined path and the displacement and stress concentration of adjacent teeth are minimized. The spatial coordinates of the final anchorage location are mapped to the anatomical location in the patient's actual oral cavity structure, and the type of anchorage device is determined based on the anatomical characteristics of the anchorage action area, including dental anchorage, micro-implant anchorage, or skeletal anchorage.
2. The method for assisting in the design of orthodontic schemes based on a digital twin of tooth movement as described in claim 1, characterized in that: The construction of the three-dimensional geometric model of tooth-periodontal ligament-alveolar bone includes: Three-dimensional volume data containing teeth, periodontal ligament and alveolar bone tissue were obtained by intraoral cone-beam CT scanning, and three-dimensional point cloud data of the crown surface were obtained by intraoral scanning and reconstructed into a three-dimensional crown surface model. The three-dimensional surface model of the tooth crown and the cone-beam CT data of the oral cavity are imported into the same spatial coordinate system. The spatial transformation matrix is calculated based on the corresponding anatomical structure to form fused data in a unified coordinate system. The fused data is structurally segmented, and the alveolar bone region and tooth region are extracted based on the differences in CT grayscale distribution. The periodontal ligament region is constructed based on the spatial gap between the outer contour of the tooth root and the inner wall of the alveolar bone. Each region is converted into a three-dimensional surface boundary and integrated into a three-dimensional geometric model of tooth-periodontal ligament-alveolar bone.
3. The method for assisting in the design of orthodontic schemes based on a digital twin of tooth movement as described in claim 2, characterized in that: The discretization of the three-dimensional geometric model into a finite element mesh includes: spatially discretizing the tooth region, periodontal ligament region, and alveolar bone region respectively, so that each region forms a finite element mesh structure composed of nodes and elements, and a continuous node connection relationship is formed between the periodontal ligament elements, tooth elements, and alveolar bone elements.
4. The method for assisting in the design of orthodontic schemes based on a digital twin of tooth movement as described in claim 2, characterized in that: The formation of the individualized digital twin of tooth movement includes: A three-dimensional geometric model after finite element mesh discretization is obtained, and a basic biomechanical model of the patient's oral cavity structure is established. The tooth structure is the main body of motion, the periodontal ligament is the mechanical transmission medium, and the alveolar bone is the supporting structure. A mechanical coupling system is formed through node connection relationship, which constitutes a virtual physical system describing the tooth movement process. In the basic biomechanical model, the initial state space of the patient's oral structure is established. By spatially registering the tissue grayscale information in the oral cone-beam CT data with the surface morphology of the crown, a virtual mapping of the patient's oral structure is formed. Define the structural state variables of tooth position state, periodontal ligament deformation state, and alveolar bone stress state. When the orthodontic force is applied to the tooth, the tooth displacement, periodontal ligament stress change and alveolar bone stress distribution are obtained by finite element solution. The results are recorded as new virtual physical system states in the model state library. The updated tooth position is used as the new calculation starting point to form a dynamic evolution model of the tooth movement process. The CT grayscale value of each finite element in the alveolar bone region is extracted, and then converted into the element elastic modulus using a mapping function, as follows: in, This represents the elastic modulus of the alveolar bone finite element; Represents the CT grayscale value of a finite element element; This represents the mapping ratio coefficient from CT grayscale values to elastic modulus; This represents the basic elasticity correction factor; Based on the patient's age and periodontal tissue condition, the viscoelastic parameters of the periodontal ligament unit are determined to ensure that the stress-strain relationship of the periodontal ligament satisfies the following: in, Indicates the periodontal ligament at any time The stress; Indicates the elastic modulus of the periodontal ligament; Indicates the periodontal ligament at any time The strain; Indicates the viscosity coefficient of the periodontal ligament; Linear elastic mechanical parameters are assigned to the tooth unit so that the stress-strain relationship of the tooth satisfies: in, This represents the stress in a tooth element; This represents the elastic modulus of tooth tissue; Indicates the strain of the tooth element; After assigning mechanical property values to all finite element units of the tooth, periodontal ligament, and alveolar bone, a personalized digital twin of tooth movement is formed.
5. The method for assisting in the design of orthodontic schemes based on a digital twin of tooth movement as described in claim 4, characterized in that: The calculation of the corrective force vector includes: In the individualized digital twin of tooth movement, the initial position coordinate vector and the target position coordinate vector of the target tooth are defined, and the target displacement vector is determined, expressed as: in, Represents the target displacement vector; Represents the target position coordinate vector; Represents the initial position coordinate vector; The target displacement vector is applied as a constraint to the finite element nodes of the tooth. The force-displacement relationship is established through the overall stiffness matrix of the finite element system. The orthodontic force vector acting on the tooth node is obtained by solving the problem. The orthodontic force vector is then mapped to the spatial position of the tooth crown to obtain the actual direction and point of application of the orthodontic force that can be applied.
6. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the steps of the oral orthodontic scheme design assistance method based on a digital twin of tooth movement as described in any one of claims 1 to 5.
7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the oral orthodontic scheme design assistance method based on a digital twin of tooth movement as described in any one of claims 1 to 5.