Dental model optimization method, dental model, electronic equipment and computer readable storage medium

Abstract

The embodiment of the invention relates to the field of tooth orthodontics, and discloses a dental cast optimization method, a dental cast, electronic equipment and a computer readable storage medium. According to the method, firstly, topological optimization is carried out on a solid dental model grid to obtain a hollow dental model grid, then pressed film finite element simulation is carried out on the hollow dental model grid, and personalized stress distribution of the dental model grids of different structures is obtained according to pressed film finite element simulation results. Then selecting two points with the maximum stress below the lowest point of the gingival line of each tooth as supporting points, and finally determining the position and direction of the supporting structure according to the two supporting points. Due to the fact that the structures of different dental cast grids are different, the stress distribution of the different dental cast grids is different, and the positions and the directions of the added supporting structures are different, the positions and the directions of the added supporting structures are determined by obtaining the stress distribution of each dental cast grid. The supporting structure added in the final target dental cast grid can be most suitable for the current dental cast grid.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of orthodontics, and particularly to a method for optimizing dental models, a dental model, an electronic device, and a computer-readable storage medium. Background Technology

[0002] The fabrication process of invisible aligners generally includes obtaining a digital model of the patient's teeth, 3D printing the dental mold, molding, marking, cutting, polishing, sorting, cleaning, and packaging. In the 3D printing of the dental mold, a 3D printer is used with photosensitive resin as the raw material. However, the initial digital model of the teeth is usually a solid model. Directly 3D printing the dental mold from this solid model would be very wasteful of resin material. Current technology typically uses commercial software to perform shelling and support operations, generating a hollow digital model of the teeth with a honeycomb-like support structure at the bottom. The dental mold is then 3D printed based on this hollow model. This saves photosensitive resin material while ensuring the compressive strength of the dental mold during molding.

[0003] However, when using the above method to perform shelling and support operations, only the pre-set support structures with regular shapes in commercial software can be added. It is impossible to generate the most suitable support structure for different jaw mesh shapes. In other words, it is impossible to generate a support structure that can save photosensitive resin material to the greatest extent and meet the compressive strength requirements during molding for different tooth digital models. Summary of the Invention

[0004] The purpose of this invention is to provide a dental model optimization method, a dental model, an electronic device, and a computer-readable storage medium, so that the most suitable support structure can be generated in a personalized manner for jaw meshes of different shapes.

[0005] To address the aforementioned technical problems, embodiments of the present invention provide a dental model optimization method, comprising: performing topology optimization on an acquired first dental model mesh to obtain a second dental model mesh, wherein the first dental model mesh is a solid structure and the second dental model mesh is a hollow structure; performing pressure finite element simulation on the second dental model mesh to calculate the stress distribution of the second dental model mesh; based on the gingival line parameters of each tooth, extracting the two points with the highest stress below the lowest point of each gingival line on the inner layer mesh of the hollow part of the second dental model mesh as the first support point and the second support point; determining the setting position and direction of the support structure according to the first support point and the second support point; generating the support structure in the second dental model mesh according to the setting position and direction of the support structure to obtain the target dental model mesh.

[0006] An embodiment of the present invention also provides a dental model, which is obtained by optimizing the dental model using the above-described dental model optimization method.

[0007] Embodiments of the present invention also provide an electronic device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the dental model optimization method as described above.

[0008] Embodiments of the present invention also provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-described dental model optimization method.

[0009] In this embodiment of the invention, a hollow dental model mesh is first obtained by topology optimization of the solid dental model mesh. Then, a pressure-molding finite element simulation is performed on the hollow dental model mesh. Based on the simulation results, the personalized stress distribution of different dental model mesh structures is obtained. Next, the two points with the highest stress below the lowest point of the gingival line of each tooth are selected as support points. Finally, the position and orientation of the support structure are determined based on these two support points. Since different dental model meshes have different structures and stress distributions, the position and orientation of the added support structure will also differ. This invention determines the position and orientation of the added support structure by obtaining the stress distribution of each dental model mesh itself, ensuring that the support structure added to the final target dental model mesh is the most suitable for the current dental model mesh.

[0010] In another example, after obtaining the target dental model mesh, the process includes: continuously adjusting the cross-sectional dimensions of the support structure and performing a pressure-film finite element simulation on the target dental model mesh; during the pressure-film finite element simulation, obtaining the target cross-sectional dimensions based on the cross-sectional dimensions corresponding to each displacement of the target dental model mesh within a preset threshold range, wherein the target cross-sectional dimension is the smallest of all cross-sectional dimensions; adjusting the cross-sectional dimensions of the support structure to the target cross-sectional dimensions. After generating the support structure, the dimensions of the support structure are further optimized to reduce the size of the support structure while ensuring compressive strength, thereby further reducing material waste.

[0011] In another example, topology optimization is performed on the acquired first dental model mesh to obtain a second dental model mesh. This includes: performing topology optimization calculations on the structure of the first dental model mesh under strength and volume constraints to obtain the second dental model mesh. It also includes: performing topology optimization calculations on the structure of the first dental model mesh under strength and volume constraints to obtain the wall thickness data corresponding to the hollow portion; and generating the second dental model mesh based on the wall thickness data and the first dental model mesh. During topology optimization, the optimized complete mesh can be generated directly; alternatively, the wall thickness data of the hollow portion can be calculated, and then the optimized mesh can be calculated based on the wall thickness data and the original mesh. Using both methods for topology optimization of dental model meshes is applicable to more scenarios.

[0012] In another example, when the lowest point of the gingival line changes, the method further includes: obtaining the gingival line parameters and arch curve parameters after the change; obtaining a first positioning point from the gingival line parameters, wherein the distance between the first positioning point and the changed lowest point is within a preset range; obtaining a second positioning point from the arch curve parameters, wherein the second positioning point is the point in the arch curve parameters closest to the first positioning point; and adjusting the position and orientation of the support structure based on the first and second positioning points. When the hollow dental model mesh changes due to changes in the patient or the same patient being in different stages of orthodontic treatment, the position of the support structure can be adjusted using gingival line and arch curve data to ensure that the position and orientation of the support structure remain optimal through a simple means.

[0013] In another example, the dental model optimization method also includes calculating the undercut height based on the second dental model mesh, generating an undercut cube triangular mesh based on the undercut height, and performing a Boolean subtraction operation on the target dental model mesh and the undercut cube mesh to obtain the undercut target dental model mesh. Performing the undercut operation on the dental model ensures that the bottom surface of the final generated dental model is flat. Attached Figure Description

[0014] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0015] Figure 1 This is a schematic flowchart of a dental model optimization method according to an embodiment of the present invention;

[0016] Figure 2 This is a schematic diagram of a topology optimization process according to an embodiment of the present invention;

[0017] Figure 3 It is a dental model according to an embodiment of the present invention, in which the position and orientation of the supporting structure are determined;

[0018] Figure 4 This is a schematic diagram of a support structure according to an embodiment of the present invention;

[0019] Figure 5 It is a certain isosurface of the SDF of the dental model prototype structure 10 according to an embodiment of the present invention;

[0020] Figure 6 It is a certain isosurface of the SDF of the support structure according to an embodiment of the present invention;

[0021] Figure 7It is a hollow inner mesh with a support structure after the triangular piece is flipped according to an embodiment of the present invention;

[0022] Figure 8 It is a target dental model mesh according to an embodiment of the present invention;

[0023] Figure 9 This is a schematic diagram of an electronic device according to another embodiment of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the various embodiments of the present invention to facilitate a better understanding of this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various changes and modifications based on the following embodiments. The division of the various embodiments below is for ease of description and should not constitute any limitation on the specific implementation of the present invention. The various embodiments can be combined with and referenced by each other without contradiction.

[0025] One embodiment of the present invention relates to a dental model optimization method, which can be applied to terminals with dental model design functions (such as mobile phones, computers, and other terminal devices). In this embodiment, the dental model optimization method includes: performing topology optimization on an acquired first dental model mesh to obtain a second dental model mesh, wherein the first dental model mesh is a solid structure and the second dental model mesh is a hollow structure; performing pressure finite element simulation on the second dental model mesh to calculate the stress distribution of the second dental model mesh; based on the gingival line parameters of each tooth, extracting the two points with the highest stress below the lowest point of each gingival line on the inner layer mesh of the hollow part of the second dental model mesh as the first support point and the second support point; determining the setting position and direction of the support structure according to the first support point and the second support point; generating the support structure in the second dental model mesh according to the setting position and direction of the support structure to obtain the target dental model mesh. Since different dental model meshes have different structures and stress distributions, the position and direction of adding the support structure also differ. The present invention determines the position and direction of adding the support structure by obtaining the stress distribution of each dental model mesh itself, so that the support structure added to the final target dental model mesh is the most suitable for the current dental model mesh. The following is a detailed description of the implementation details of the dental model optimization method in this embodiment. The following content is only for the convenience of understanding and is not necessary for implementing this solution.

[0026] like Figure 1 As shown, in step 101, the obtained first dental model mesh is topologically optimized to obtain a second dental model mesh, wherein the first dental model mesh is a solid structure and the second dental model mesh is a hollow structure.

[0027] In one example, step 101 includes performing topology optimization calculations on the structure of the first dental model mesh using strength and volume constraints as constraints to obtain the second dental model mesh. Alternatively, performing topology optimization calculations on the structure of the first dental model mesh using strength and volume constraints as constraints to obtain the wall thickness data corresponding to the hollow portion; and generating the second dental model mesh based on the wall thickness data and the first dental model mesh. Specifically, performing topology optimization calculations on the structure of the first dental model mesh using strength and volume constraints includes: calculating a first topology-optimized dental model mesh that satisfies the first constraint condition using volume constraints as the first constraint condition; performing pressure finite element simulation on the first topology-optimized dental model mesh; and selecting topology optimization data that satisfies the second constraint condition related to the strength constraint.

[0028] Specifically, using volume constraints as the first constraint, calculating the first topology-optimized dental model mesh that satisfies the first constraint includes: establishing a three-dimensional continuum topology optimization model under volume constraints, with material distribution as the design variable and minimum compliance as the objective function. The topology optimization process is described below; see details. Figure 2 .

[0029] First, in step 201, the original data is input, including iteration parameters (maximum number of iterations and convergence factor), material parameters (elastic modulus and Poisson's ratio), coordinates and degree-of-freedom numbers of the load application points, and coordinates and degree-of-freedom numbers of the constraint nodes. Then, in step 202, the finite element initialization definition is performed, including the definition of the element stiffness matrix and the integration of the overall stiffness matrix. Specifically, in this embodiment, the finite element representation based on the improved SIMP model is as follows:

[0030] Replacing discrete functions with continuous functions is a fundamental method for handling discrete variable problems in numerical computation. During optimization, many elements with values ​​between 0 and 1 are generated. Such structures are difficult to manufacture. To address this problem, a penalty factor is typically used to suppress their occurrence. Using the variable density method and introducing a penalty factor, the relationship between the variable density xi and the elastic modulus Ei based on the SIMP model (density-stiffness interpolation model) is as follows:

[0031]

[0032] Where E0 is the elastic modulus of the solid material, and p is the penalty factor (p > 1). By improving the SIMP model, we obtain:

[0033]

[0034] Among them, E minThis is the elastic modulus of the empty material. To avoid singularities in the finite element stiffness matrix, this value is generally not zero. The improved SIMP model makes the penalty factor and the elastic modulus of the empty material independent of each other, which has greater advantages compared to the original model.

[0035] Using the improved SIMP model, based on Hooke's law, the three-dimensional constitutive matrix of isotropic material element i can be expressed as:

[0036]

[0037] Where Xi represents the density of material element i; Ei represents the elastic modulus of material element i. The constitutive matrix composed of unit Young's moduli is:

[0038]

[0039] Where υ is the Poisson's ratio for isotropic materials. Based on the finite element principle, the stiffness matrix of an elastic solid element is the element constitutive matrix. The volume integral of the strain matrix can be expressed as:

[0040]

[0041] Where, ξ e (e = 1, 2, 3) represents the natural coordinate system of the hexahedral element, and B is the strain matrix, describing the relationship between nodal displacements and strains of the element. Based on the SIMP model, the element stiffness matrix can be expressed as:

[0042]

[0043] In the formula,

[0044]

[0045] Substituting equation (1) into equation (2) and further simplifying, we get:

[0046]

[0047] In the formula, k m (m = 1, 2, 3, 4, 5, 6) is a 6×6 symmetric matrix, and It is positive definite. The global stiffness matrix is ​​the set of element stiffness matrices, expressed as:

[0048]

[0049] Where n is the number of elements, and A represents the permutations and combinations of ki from 1 to n. Based on the definition of the total stiffness matrix, equation (3) can be further expressed as:

[0050]

[0051] in, It is a constant stiffness matrix.

[0052] In step 203, finite element calculations are performed, i.e., the element nodal displacements are calculated using finite element methods. Based on the improved SIMP model, the following can be obtained:

[0053]

[0054] Finally, according to the equilibrium equation:

[0055]

[0056] The nodal displacement vectors can be obtained by solving. Where F is the nodal force vector.

[0057] Then, compliance and sensitivity are calculated in step 204;

[0058] The minimum compliance problem aims to find the material density distribution that minimizes structural deformation under specified loads and constraints. Therefore, the compliance of a structure can be defined as:

[0059]

[0060] Introducing volume constraints, the minimum compliance problem can be reduced to:

[0061] Find x = [x1, x2, ... x n ] T

[0062] minimize

[0063] Constraints:

[0064]

[0065] x∈χ,χ={x∈R n :0≤x≤1}

[0066] Among them, density Determined by the density filtering function, where n is the total number of discrete elements in the structural design domain, and v = [v1,...,v...]. n ] T It is a unit volume vector. It specifies the upper limit of the volume of the structural design domain.

[0067] Then, sensitivity filtering is performed in step 205;

[0068] Topology optimization models based on the variable density method are prone to numerical problems such as grid dependence, checkerboard pattern, and local extrema. To address these issues, the most common approach is to use density filtering. This paper proposes the following improved density filtering function based on existing literature:

[0069]

[0070] Among them, v i It is the unit volume, H ij It is a weighting factor, N i It is related to unit x i Adjacent units, defined as:

[0071] N i ={j:dist(i,j)≤R}

[0072] Where, the operator dist(i,j) represents the center distance between cells i and j, and R represents the filtering radius. The weighting factor H... ij for:

[0073] H ij =R-dist(i,j)

[0074] Filtration density This is the corrected density. Introducing it into the SIMP model, we get:

[0075]

[0076] Then, in step 206, the Lagrange multipliers are calculated and the design variables are updated;

[0077] This embodiment also utilizes the Optimality Criteria (OC) method to solve the topology optimization model. The OC method does not directly optimize the objective function; instead, it uses the Karush-Kuhn-Tucker (KT) conditions, which the optimal solution should satisfy in mathematics, as the criteria that the optimal structure should satisfy. These conditions are:

[0078] Volume constraint function For design variable x e The partial derivatives are:

[0079]

[0080] In the formula,

[0081] In this embodiment, the mesh elements are cubic units of unit volume; therefore, v i =v j =ve =1.

[0082] Compliance on design variable x e The partial derivatives are:

[0083]

[0084] In the formula,

[0085]

[0086] Total stiffness versus design variables The partial derivatives are:

[0087]

[0088] After further analysis, the following was obtained:

[0089]

[0090] Based on the overall stiffness matrix, we can obtain:

[0091]

[0092] Combining the above formula, we can finally obtain:

[0093]

[0094] because It is the set form of the element stiffness matrix, and the above formula can be expressed similarly as:

[0095]

[0096] In the formula, It is the element nodal displacement vector, because It is positive definite, therefore it has

[0097] In the formula, λ is the Lagrange multiplier. The above formula can be further expressed as:

[0098]

[0099] In the formula, B e =1. Within an iterative unit, a large change in relative density from no material to material is not allowed; therefore, a shift limit m is introduced into the design variables. During the iteration process, considering the shift limit of the design variables, the iterative format of the density variable is obtained:

[0100]

[0101] In the formula, m is the movement limit, and η is the damping coefficient, both ranging from 0 to 1. The purpose of introducing the damping coefficient and movement limit is to stabilize the iteration. η and m control the possible changes in each iteration step, and their values ​​can be adjusted according to the efficiency of the method. For the minimum compliance problem, Sigmund, based on his research, suggested parameter values ​​of m = 0.2 and η = 0.5. The only remaining unknown in the formula is λ, and the following condition is satisfied:

[0102]

[0103] Based on the above formula, λ can be obtained using the bisection method. Furthermore, the convergence criterion must satisfy the following condition:

[0104] ||x new -x|| ∞ ≤ε

[0105] In the formula, ε is the allowable error limit, which is taken as 0.001 in this paper.

[0106] Finally, in step 207, convergence is determined according to the above formula. If the condition is met, the final result (compliance, displacement, density distribution cloud map) is output; otherwise, the process jumps to step 203.

[0107] After obtaining the optimized structure, the output optimized structure is subjected to pressure membrane finite element calculation to calculate the stress and displacement of the structure. If the stress of the structure meets the strength requirements and the displacement meets the stiffness requirements, the output optimized structure is the final result; otherwise, the process jumps to step 201 to reset the upper limit of the optimized volume.

[0108] In step 102, pressure film finite element simulation is performed on the second dental mold mesh to calculate the stress distribution of the second dental mold mesh.

[0109] In step 103, based on the gingival line parameters of each tooth, the two points with the greatest stress below the lowest point of each gingival line are extracted on the inner mesh of the hollow part of the second dental model mesh as the first support point and the second support point.

[0110] In one example, for the optimized dental model prototype structure 10, i.e. the second dental model mesh, a pressure simulation finite element calculation is performed to obtain the stress distribution of the dental model prototype structure 10. The location of the maximum stress area below the gingival line of each tooth is extracted on the wall surface of the hollow part of the dental model structure, and this location is used as the support positioning point (two) of the designed support structure.

[0111] In step 104, the location and orientation of the support structure are determined based on the first support point and the second support point.

[0112] In one example, the support structure (cylinder or cuboid) is generated by using two support positioning points as the centers of the upper and lower bottom surfaces of the support structure.

[0113] In one example, when the lowest point of the gingival line changes; the method also includes:

[0114] Obtain the gingival line parameters and dental arch curve parameters after the change of the lowest point; obtain a first positioning point from the gingival line parameters, wherein the distance between the first positioning point and the changed lowest point is within a preset range, that is, it is not necessary to select the lowest point in the gingival line. Any point near the lowest point of the gingival line can be used as the first positioning point as long as the distance between it and the lowest point of the gingival line is within the preset range. In this embodiment, the preset range can be 0-0.5mm; obtain a second positioning point from the dental arch curve parameters, wherein the second positioning point is the point in the dental arch curve parameters that is closest to the first positioning point; adjust the setting position and direction of the support structure according to the first positioning point and the second positioning point.

[0115] Adjusting the setting position and orientation of the support structure according to the first positioning point and the second positioning point includes:

[0116] Obtain the normal direction of the line connecting the first and second positioning points;

[0117] A ray is formed based on the first positioning point and the normal direction;

[0118] Two intersection points between the ray and the inner mesh of the hollow part of the second dental model mesh are obtained as the third and fourth support points;

[0119] Adjust the position and orientation of the support structure according to the third and fourth support points.

[0120] Specifically, when the lowest point of the gingival line changes, the jaw mesh, gingival line data, and dental arch curve data of the optimized dental model prototype structure 10 are read. The bottom surface of the jaw mesh lies in the xoy plane, the centroid is on the z-axis, and the entire mesh is in the positive half of the z-axis space. Each tooth corresponds to a supporting cylinder. If the minimum z-coordinate of the gingival line vertex is z0, the centroid of the gingival line vertex is taken, and its z-coordinate value is modified to (z0 - (0~0.5mm) - pillarRadius) (support point coordinates), which is used as the center point of the cylinder; where pillarRadius is the radius of the cylinder. For each cylinder center point, the nearest point on the dental arch curve is found, and the normal to this nearest point on the dental arch curve is the axial direction of the cylinder. Figure 3 As shown in the middle cylinder.

[0121] In step 105, the support structure is generated in the second dental model mesh according to the setting position and orientation of the support structure, and the target dental model mesh is obtained.

[0122] In one example, the support structure is generated by using two support positioning points as the centers of the upper and lower bottom surfaces of the support structure. Figure 3 30 (cylinder or cuboid). If it is a cylinder, the diameter of the cross-section is D, and the height is L1, where L1 is the distance between the two positioning points; if it is a cuboid, the side length of the cross-section is W, and the height is L1. A schematic diagram of the specific support structure is shown below. Figure 4 As shown. The dental model prototype structure after generating the support structure is represented as the optimized dental model prototype structure 20, i.e., the target dental model mesh (e.g. Figure 8 (As shown).

[0123] The supporting structure is generated in the second dental model mesh according to its setting position and orientation, to obtain the target dental model mesh. This includes: generating a composite directed distance field based on the second dental model mesh, its setting position and orientation; generating an inner layer mesh based on the composite directed distance field; and generating the target dental model mesh based on the inner layer mesh and the outer layer mesh of the second dental model mesh.

[0124] Specifically, the data for generating the composite directed distance field (SDF) includes calculating and generating the SDF data S1 of the input dental model prototype structure 10. Figure 5 To calculate a certain isosurface of the SDF of the dental prototype structure 10, the SDF data S2 of the cylindrical axis line segment in space is calculated using the following algorithm. Figure 6 The middle part represents a certain isosurface of the calculated SDF of the support structure.

[0125] Let the center point of the cylinder be c, the axial direction be d, and the length of the cylinder be 1. In this embodiment, 1 can be 15mm to 20mm, which ensures that the cylinder can cover the span of an entire tooth in the x and y directions. The axial line segment has two endpoints, e1 and e2, where e1 is the endpoint away from the lingual side and e2 is the endpoint closer to the lingual side. Then e1 = c + ld / 2, e2 = c - ld / 2; the upper and lower bases of the cylinder can be represented as (e1, d) and (e2, d).

[0126] For a point v in space, if (v-e1)d > 0 and (v-e2)d > 0, then point v lies on the positive side of the two bottom surfaces (end faces of the supporting structure). The distance field value of this point with respect to the axis segment is the distance from this point to the endpoint e1: s = ||v-e1||

[0127] If (v-e1)d < 0 and (v-e2)d < 0, then point v lies on the negative side of the two bases, and the distance field value of this point with respect to the axis segment is the distance from this point to the endpoint e2: s = ||v-e1||

[0128] In other cases, where vertex V lies between the two bases, the distance field value of that point to the axis segment is the distance from that point to the line containing the axis segment: s = ||(vc)×d||

[0129] For each axis segment, calculate a series of s values ​​using the method described above, and take the minimum value among them, which is the final distance field value of point V.

[0130] Then, all elements outside the mesh in S1—that is, elements in S1 greater than 0—are set to 0; the absolute value of the elements outside the mesh in S1—that is, elements in S1 not greater than 0—is taken and subtracted by an offset DFoffset = thickShell - pillarRadius, where thickShell is the set shell thickness and pillarRadius is the radius of the pillar.

[0131] Compare the elements in S1 and S2 one by one. If the element in S1 is less than the element in S2 under the same index, then assign the latter to the former. S1 after this processing is the SDF data that takes into account the original jaw mesh and columnar support structure.

[0132] The marching cubes algorithm is used to extract the 0 isosurface from the composite S1 data to generate a triangular mesh. Figure 7 The image shows a hollow inner mesh with a supporting structure after the triangular piece has been flipped.

[0133] In one example, the dental model optimization method further includes: calculating the undercut height based on the second dental model mesh, generating an undercut cube triangular mesh based on the undercut height, and performing a mesh Boolean subtraction operation on the target dental model mesh and the undercut cube mesh to obtain the undercut target dental model mesh.

[0134] Specifically, the incisal height needs to be calculated first: if the jaw mesh of the dental model prototype structure 10 does not include the hard palate, the incisal height zTop is the z-coordinate value after the lowest point of the gingival line of teeth 4 to 6 is moved -4mm to -6mm in the z-axis direction; if the jaw mesh includes the hard palate, the incisal height is the z-coordinate value after the lowest point of the hard palate is moved -0.2mm to -1mm in the z-axis direction. When generating the incisal cube triangular mesh, first generate a unit cube triangular mesh with a side length of 1mm centered at the origin; then multiply the coordinates of all vertices of the unit cube by 100 to obtain a cube mesh with a side length of 100mm; finally, translate the cube mesh in the positive Z-axis direction by a distance of (zTop-50) to obtain the incisal cube triangular mesh, where zTop is the previously calculated incisal height.

[0135] Finally, the jaw mesh and inner mesh of the dental model prototype structure 10 are spliced ​​together to obtain a double-layer mesh.

[0136] Performing a Boolean subtraction operation between the double-layer mesh and the bottom-cut cube mesh completes the bottom-cutting, resulting in the final shelled and supported mesh, which is the target dental mold mesh. Figure 8 As shown.

[0137] In one example, after obtaining the target dental model mesh, the process includes: continuously adjusting the cross-sectional dimensions of the support structure and performing pressure finite element simulation on the target dental model mesh; during the pressure finite element simulation, obtaining the target cross-sectional dimensions based on the cross-sectional dimensions corresponding to each displacement of the target dental model mesh within a preset threshold range, wherein the target cross-sectional dimensions are the smallest of the cross-sectional dimensions; and adjusting the cross-sectional dimensions of the support structure to the target cross-sectional dimensions.

[0138] In this embodiment, a hollow dental model mesh is first obtained by topology optimization of the solid dental model mesh. Then, a pressure-molding finite element simulation is performed on the hollow dental model mesh. Based on the simulation results, the personalized stress distribution of different dental model mesh structures is obtained. Next, the two points with the highest stress below the lowest point of the gingival line of each tooth are selected as support points. Finally, the position and orientation of the support structure are determined based on these two support points. Since different dental model meshes have different structures and stress distributions, the position and orientation of the added support structure will also differ. This invention determines the position and orientation of the added support structure by obtaining the stress distribution of each dental model mesh, ensuring that the support structure added to the final target dental model mesh is the most suitable for the current dental model mesh.

[0139] The steps described above are for clarity only. In practice, they can be combined into one step or some steps can be broken down into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this patent. Adding insignificant modifications or introducing insignificant designs to the algorithm or process, but without changing the core design of the algorithm and process, are also within the scope of protection of this patent.

[0140] Another embodiment of the present invention relates to a dental model, which is obtained by optimizing the dental model using the above-described dental model optimization method.

[0141] Another embodiment of the present invention relates to an electronic device, such as Figure 9 As shown, it includes at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the dental model optimization method as described above.

[0142] The memory and processor are connected via a bus, which can include any number of interconnecting buses and bridges, connecting various circuits of one or more processors and memories. The bus can also connect various other circuits, such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and will not be described further herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by the processor is transmitted over the wireless medium via an antenna, which further receives data and transmits it to the processor.

[0143] The processor manages the bus and general processing, and also provides various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory is used to store data used by the processor during operation.

[0144] Another embodiment of the present invention relates to a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the above-described method embodiments.

[0145] That is, those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0146] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the present invention.

Claims

1. A method of dental cast optimization, characterized by, The method comprises the following steps: topology optimization is performed on the obtained first dental mold grid to obtain a second dental mold grid, wherein the first dental mold grid is a solid structure, and the second dental mold grid is a hollow structure; film pressing finite element simulation is performed on the second dental mold grid to calculate the stress distribution of the second dental mold grid; based on the gum line parameters of each tooth, two points with the maximum stress below the lowest point of each gum line are extracted from the inner layer grid of the hollow part of the second dental mold grid as a first support point and a second support point; the setting position and direction of the support structure are determined according to the first support point and the second support point; a support structure is generated in the second dental mold grid according to the setting position and direction of the support structure to obtain a target dental mold grid.

2. The dental cast optimization method of claim 1, wherein, After obtaining the target dental mold grid, the method further comprises the following steps: the cross-sectional size of the support structure is continuously adjusted, and film pressing finite element simulation is performed on the target dental mold grid; in the film pressing finite element simulation process, a target cross-sectional size is obtained based on each cross-sectional size corresponding to each displacement of the target dental mold grid within a preset threshold range, wherein the target cross-sectional size is the minimum size among the cross-sectional sizes; the cross-sectional size of the support structure is adjusted to the target cross-sectional size.

3. The dental cast optimization method of claim 1, wherein, The topology optimization of the obtained first dental mold grid to obtain a second dental mold grid comprises the following steps: topology optimization calculation is performed on the structure of the first dental mold grid with strength constraints and volume constraints as constraint conditions to obtain the second dental mold grid.

4. The dental cast optimization method of claim 1, wherein, The topology optimization of the obtained first dental mold grid to obtain a second dental mold grid further comprises the following steps: topology optimization calculation is performed on the structure of the first dental mold grid with strength constraints and volume constraints as constraint conditions to obtain wall thickness data corresponding to the hollow part; the second dental mold grid is generated according to the wall thickness data and the first dental mold grid.

5. The dental cast optimization method of any one of claims 3-4, wherein, The topology optimization calculation of the structure of the first dental mold grid with strength constraints and volume constraints as constraint conditions comprises the following steps: the first topology optimization dental mold grid satisfying the first constraint condition is calculated from the first dental mold grid with the volume constraint as the first constraint condition; film pressing finite element simulation is performed on the first topology optimization dental mold grid to select topology optimization data satisfying the second constraint condition related to the strength constraint.

6. The dental cast optimization method of claim 1, wherein, When the lowest point of the gum line changes, the method further comprises the following steps: obtain the gum line parameters and the dental arch curve parameters after the change of the lowest point; obtain a first positioning point from the gum line parameters, wherein the distance between the first positioning point and the changed lowest point is within a preset range; obtain a second positioning point from the dental arch curve parameters, wherein the second positioning point is the point in the dental arch curve parameters closest to the first positioning point; adjust the setting position and direction of the support structure according to the first positioning point and the second positioning point.

7. The dental cast optimization method of claim 6, wherein, The adjustment of the setting position and direction of the support structure according to the first positioning point and the second positioning point comprises the following steps: obtain the normal direction of the line connecting the first positioning point and the second positioning point; form a ray according to the first positioning point and the normal direction; obtaining two intersection points of the ray and the inner layer grid of the second dental mold mesh hollow part as a third support point and a fourth support point; adjusting the setting position and direction of the support structure according to the third support point and the fourth support point.

8. The dental cast optimization method of claim 1, wherein, generating the support structure in the second dental mold mesh according to the setting position and direction of the support structure, to obtain a target dental mold mesh, comprising: generating a composite directed distance field according to the second dental mold mesh, the setting position and the direction; generating an inner layer grid according to the composite directed distance field; generating the target dental mold mesh according to the inner layer grid and the outer layer grid of the second dental mold mesh.

9. The dental cast optimization method of claim 1, wherein, Further comprising: calculating a undercut height according to the second dental mold mesh, generating a undercut square mesh according to the undercut height, and performing a mesh Boolean subtraction operation on the target dental mold mesh and the undercut square mesh to obtain a target dental mold mesh after undercutting.

10. A dental model, characterized in that The dental mold is optimized by the dental mold optimization method in any one of claims 1-9.

11. An electronic device, comprising: comprising: at least one processor; and a memory connected in communication with the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the dental mold optimization method in any one of claims 1 to 9.

12. A computer readable storage medium storing a computer program, wherein the computer program comprises program instructions configured to cause a processor to perform the method according to any one of claims 1 to 11. The computer program is executed by the processor to implement the dental mold optimization method in any one of claims 1 to 9. The computer program is executed by the processor to implement the dental mold optimization method in any one of claims 1 to 9.

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