Inverted concave filling method, manufacturing method and equipment of dental appliance and medium

Abstract

The embodiment of the invention relates to the technical field of tooth correction, and discloses an undercut filling method, a tooth appliance manufacturing method, equipment and a medium. The undercut filling method comprises the following steps: acquiring a digital dental model, wherein an undercut area is formed between teeth of the digital dental model; generating an envelope surface surrounding the digital tooth jaw model; and performing smooth deformation on the envelope surface by taking the digital tooth jaw model as a target to obtain a target digital tooth jaw model with the undercut area being filled. At least the undercut filling step is simplified, and the implementation difficulty is reduced.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of dental orthodontics, and in particular to a method for filling an undercut, a method for manufacturing a dental orthodontic appliance, equipment and a medium. Background Art

[0002] Undercuts can be divided into tooth undercuts and tissue undercuts. Tooth undercuts refer to the area on the crown between the observation line and the gums, while tissue undercuts refer to the area below the tissue protrusion. The presence of undercuts will affect the design and wearing of the braces, and thus affect the treatment effect.

[0003] At present, in order to overcome the adverse effects of undercuts, the dental model is usually tested to determine whether it has an undercut. If it has an undercut, a corresponding undercut model is generated based on the detected undercut area. Then, when printing the dental model, the undercut model is combined with the undercut area corresponding to the dental model, and then the dental model with the combined undercut structure is printed.

[0004] However, the above-mentioned undercut filling method requires the detection of the undercut area, the generation of the undercut structure and the combination of the undercut structure. The steps are cumbersome and the implementation is complicated. In addition, the detection of the undercut area and the generation of the undercut structure have high requirements. Otherwise, the matching degree between the undercut structure and the dental model is not high, and it is difficult to combine the undercut structure onto the dental model for printing, which also leads to high difficulty in implementation. Summary of the invention

[0005] The embodiments of the present application provide a method for filling an undercut, a method for manufacturing a dental appliance, an apparatus, and a medium, which at least help to simplify the steps for filling an undercut and reduce the difficulty of implementation.

[0006] According to some embodiments of the present application, on the one hand, the embodiments of the present application provide a method for filling an undercut, comprising: obtaining a digital dental model, wherein the digital dental model has an undercut area between teeth; generating an envelope surface surrounding the digital dental model; taking the digital dental model as a target, smoothly deforming the envelope surface to obtain a target digital dental model with the undercut area filled.

[0007] In some embodiments, taking the digital dental model as a target, smoothly deforming the envelope surface includes: deforming the envelope surface to approximate the digital dental model and satisfy a smoothness constraint.

[0008] In some embodiments, the smoothness constraint refers to a requirement that the envelope surface obtained after each vertex on the envelope surface moves in the process of approximating the surface of the digital dental model remains smooth.

[0009] In some embodiments, the smoothness constraint is implemented by adding a preset smoothness constraint term to the target displacement of each vertex on the envelope surface approximating the surface of the digital dental model.

[0010] In some embodiments, the preset smoothness constraint item is a distance value between the position of the vertex to be moved on the envelope surface and the neighborhood reference coordinate positions of each of its neighboring vertices.

[0011] In some embodiments, the expression of the preset smoothness constraint item is: D1 = neighborhood reference coordinate position - coordinate position of the vertex to be moved on the envelope surface, wherein D1 is the target smooth displacement of the vertex to be moved on the envelope surface, and the neighborhood reference coordinate position includes the mean of the coordinate positions of each vertex in the 1-ring neighborhood of the vertex to be moved, the median of the coordinate positions of each vertex in the 1-ring neighborhood of the vertex to be moved, the mean of the coordinate positions of each vertex in the 2-ring neighborhood of the vertex to be moved, or the median of the coordinate positions of each vertex in the 2-ring neighborhood of the vertex to be moved.

[0012] In some embodiments, before the envelope surface is smoothly deformed with the digitized dental model as the target, the method further includes: generating a distance field of the digitized dental model; the envelope surface is smoothly deformed with the digitized dental model as the target, including: determining the target deformation displacement of each vertex on the envelope surface to the surface of the digitized dental model according to the distance field of the digitized dental model; determining the target smooth displacement of each vertex on the envelope surface according to the preset smooth constraint item; determining the target displacement of each vertex on the envelope surface according to the corresponding target deformation displacement and the target smooth displacement; and moving each vertex on the envelope surface by the target displacement along the normal direction.

[0013] In some embodiments, determining the target displacement of each vertex on the envelope surface based on the corresponding target deformation displacement and the target smooth displacement includes: performing weighted averaging on the target deformation displacement and the target smooth displacement, and using the result of the weighted average as the target displacement of the corresponding vertex on the envelope surface.

[0014] In some embodiments, the weight value ranges of the target deformation displacement and the target smooth displacement are both (0, 1).

[0015] In some embodiments, the weight of the target deformation displacement decreases as the number of movements increases.

[0016] In some embodiments, the weight of the target smooth displacement varies with the gap between teeth on the digital dental model.

[0017] In some embodiments, generating the distance field of the digitized dental model includes: generating a point cloud grid array surrounding the digitized dental model, the dimension of the point cloud grid array is l*m*n, and l, m, and n are all positive integers; respectively determining the minimum distance from each vertex in the point cloud grid array to the surface of the digitized dental model, so as to generate the distance field of the point cloud grid array relative to the digitized dental model according to the minimum distance corresponding to each vertex in the point cloud grid array.

[0018] In some embodiments, determining the target deformation displacement from each vertex on the envelope surface to the surface of the digitized dental model based on the distance field of the digitized dental model includes: determining the 8 vertices closest to each vertex on the envelope surface on the point cloud grid array; interpolating the distance parameters of the 8 vertices in the distance field of the digitized dental model to determine the distance parameters of the corresponding vertices on the envelope surface as the target shrinkage displacement.

[0019] In some embodiments, after moving each vertex on the envelope surface along the normal direction by the target displacement, the method further includes: detecting whether the reference distance of the envelope surface after the movement is less than a preset threshold; if it is not less than the preset threshold, returning to the step of determining the target contraction displacement from each vertex on the envelope surface to the surface of the dental model according to the distance field of the dental model, until the reference distance of the envelope surface after the movement is less than the preset threshold; wherein the preset threshold is less than or equal to 0.05 mm, and the reference distance includes the maximum distance from the vertex on the envelope surface after the movement to the surface of the dental model, and / or the difference between the distance from the vertex on the envelope surface after the movement to the surface of the dental model and the distance from the vertex on the envelope surface to the surface of the dental model before the movement.

[0020] In some embodiments, after moving each vertex on the envelope surface along the normal direction by the target displacement, the method further includes: detecting whether the envelope surface after the move is fitted to the digital dental model in the non-undercut area; if the envelope surface after the move is not fitted to the digital dental model in the non-undercut area, returning to the step of determining the target contraction displacement of each vertex on the envelope surface to the surface of the digital dental model according to the distance field of the digital dental model, until the envelope surface after the move is fitted to the digital dental model in the non-undercut area.

[0021] In some embodiments, it is detected whether the reference distance of the envelope surface after movement is less than a preset threshold; when the reference distance of the envelope surface after movement is not less than the preset threshold, it is confirmed that the envelope surface after movement is not in contact with the digitized dental model in the non-undercut area; wherein the preset threshold is less than or equal to 0.05 mm, and the reference distance includes the maximum distance from the vertex on the envelope surface after movement to the surface of the dental model, and / or the difference between the distance from the vertex on the envelope surface after movement to the surface of the dental model and the distance from the vertex on the envelope surface before movement to the surface of the dental model.

[0022] In some embodiments, generating an envelope surface surrounding the digital dental model includes: taking the center of the digital dental model as the center of the sphere and the maximum distance from a point on the digital dental model to the center of the sphere as the radius, generating a spherical surface, and using the spherical surface as the envelope surface.

[0023] In some embodiments, generating an envelope surface surrounding the digitized dental model includes: generating a cuboid with the projections of the digitized dental model on the coordinate axes in the local coordinate system of the digitized dental model as length, width and height respectively, and with the center of the digitized dental model as the center, so as to use the surface of the cuboid as the envelope surface.

[0024] According to some embodiments of the present application, on the other hand, the embodiments of the present application further provide a method for manufacturing a dental brace, comprising: filling the undercut of a digital dental model according to the undercut filling method as described in any of the above embodiments, the target digital dental model; and generating a shell-shaped dental brace according to the target digital dental model.

[0025] In some embodiments, generating a shell-shaped dental appliance according to the target digital dental model comprises: manufacturing a positive mold of the appliance according to the target digital dental model; obtaining a shell-shaped dental appliance containing a tooth shape by hot pressing on the positive mold of the appliance; and cutting along the gum line or adjacent to the gum line on the shell-shaped dental appliance containing a tooth shape to obtain a shell-shaped dental appliance capable of accommodating the teeth.

[0026] In some embodiments, generating a shell-shaped dental appliance according to the target digital dental model includes: generating a digital appliance model that matches the target digital dental model; and manufacturing the shell-shaped dental appliance through an additive manufacturing process according to data information corresponding to the digital appliance model.

[0027] According to some embodiments of the present application, the embodiments of the present application further provide an electronic device, including: at least one processor; and,

[0028] A memory communicatively connected to 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 so that the at least one processor can execute the method for filling an undercut as described in any of the above embodiments, or execute the method for manufacturing a dental appliance as described in any of the above embodiments.

[0029] According to some embodiments of the present application, on the other hand, the embodiments of the present application further provide a computer-readable storage medium storing a computer program, characterized in that when the computer program is executed by a processor, it implements the method for filling an undercut as described in any of the above embodiments, or implements the method for manufacturing a dental appliance as described in any of the above embodiments.

[0030] The technical solution provided in the embodiment of the present application has at least the following advantages:

[0031] With the digital dental model as the target, the envelope surface surrounding the digital dental model is deformed, so that the deformed envelope surface will be close to the outer surface of the digital dental model. At the same time, because the deformation is a smooth deformation, the envelope surface in the undercut area of ​​the digital dental model will not be sunken to the point where the undercut area is completely fitted, but will remain smooth with the area around the undercut area, thereby presenting a state where the undercut area is filled. That is, the target digital dental model with the undercut area filled is obtained. In other words, by generating the target digital dental model with the undercut area filled through smooth deformation, there is no need for combination, and the filling steps of the undercut are simplified and the difficulty of implementation is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0033] Figure 1 This is a flow chart of a method for filling an undercut provided in an embodiment of the present application;

[0034] Figure 2 It is a structural schematic diagram of an undercut region on a digital dental model involved in a method for filling an undercut provided in an embodiment of the present application;

[0035] Figure 3 is a schematic structural diagram of a spherical envelope surface involved in a method for filling an undercut provided in an embodiment of the present application;

[0036] Figure 4 is a structural schematic diagram of a rectangular enveloping surface involved in a method for filling an undercut provided in an embodiment of the present application;

[0037] Figure 5 It is a schematic structural diagram of a target digital dental model involved in a method for filling an undercut provided in an embodiment of the present application;

[0038] Figure 6 is another flow chart of a method for filling an undercut provided in an embodiment of the present application;

[0039] Figure 7 is a schematic diagram of the smooth deformation of the vertex E on the envelope surface involved in the undercut filling method provided in one embodiment of the present application;

[0040] Figure 8 It is a structural schematic diagram of a smooth deformation front envelope surface and a local cross-section of a digital dental model involved in a method for filling an undercut provided in an embodiment of the present application;

[0041] Fig. 9 It is a structural schematic diagram of the envelope surface and the local cross-section of the digital dental model after the smooth deformation is completed in the undercut filling method provided in one embodiment of the present application;

[0042] Fig.10 is a structural schematic diagram of a point cloud grid array involved in a method for filling an undercut provided in an embodiment of the present application;

[0043] Fig.11 is another flow chart of a method for filling an undercut provided in an embodiment of the present application;

[0044] Fig.12 is a flow chart of a method for manufacturing an undercut dental appliance provided by an embodiment of the present application;

[0045] Fig.13 It is a schematic diagram of the structure of an electronic device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the embodiments of the present application will be described in detail below in conjunction with the accompanying drawings. However, it will be appreciated by those skilled in the art that in the embodiments of the present application, many technical details are provided in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can be implemented.

[0047] The division of the following embodiments is for the convenience of description and shall not constitute any limitation on the specific implementation of the present application. The embodiments may be combined with each other and referenced to each other without contradiction.

[0048] On the one hand, the present application provides a method for filling an undercut, which is applied to electronic devices such as computers, servers, etc. In some embodiments, the process is as follows: Figure 1 As shown, at least the following steps are included:

[0049] Step 101, obtaining a digital dental model, wherein the digital dental model has undercut areas between teeth.

[0050] In this embodiment, the undercut area is an area formed by undercuts between teeth in the digital dental model. Figure 2 The area A and area B shown in FIG. It should be noted that Figure 2 Region A and region B in FIG. 1 are merely examples of undercut regions, and Figure 2 There are also unspecified undercut areas in the schematic diagram of the digital dental model shown in , which will not be described in detail here.

[0051] In some embodiments, the digital dental model can be obtained in real time by scanning the dental model of the patient or performing graphic processing on the dental model of the patient taken. The scanning method can be electronic computed tomography (CT) and the like.

[0052] In some embodiments, the digital dental model can also be obtained in non-real time by downloading, reading memory, etc.

[0053] Of course, the above is only a specific example of the method of obtaining the digital dental model. In some embodiments, the digital dental model can also be obtained by other methods, which will not be described here one by one.

[0054] Step 102: Generate an envelope surface surrounding the digital dental model.

[0055] This embodiment does not limit the shape and specific size of the envelope surface, and it can be any envelope surface of any shape that can surround the digital dental model.

[0056] In some embodiments, the envelope surface is spherical. Figure 3 As shown, the outer sphere is the envelope surface, which surrounds the digital dental model.

[0057] At this time, since the generated envelope surface is spherical, the envelope surface before deformation is smooth. In this way, when smooth deformation is performed subsequently, the envelope surface does not need to overcome the uneven interference in the initial state, and can perform smooth deformation better and more efficiently, and the efficiency of undercut filling is also improved accordingly.

[0058] Based on this, in some embodiments, generating an envelope surface surrounding the digital dental model can be achieved in the following way: taking the center of the digital dental model as the center of the sphere and the maximum distance from a point on the digital dental model to the center of the sphere as the radius, generating a spherical surface, and using the spherical surface as the envelope surface.

[0059] At this time, the center of the digital dental model is used as the center of the sphere, so that the position of the envelope surface in space is expressed concisely, and the amount of calculation required for subsequent smooth deformation will be smaller, which improves the processing efficiency and the efficiency of undercut filling.

[0060] In some embodiments, the envelope surface is a cuboid. Figure 4 As shown, the outer rectangular block is the envelope surface, which surrounds the digital dental model.

[0061] At this time, since the position of the cuboid in space is expressed concisely, the amount of calculation required for subsequent smooth deformation will be smaller, which improves the processing efficiency and the efficiency of undercut filling.

[0062] Based on this, in some embodiments, generating an envelope surface surrounding the digitized dental model can also be achieved in the following way: generating a cuboid with the projections of the digitized dental model on the coordinate axes in the local coordinate system where the digitized dental model is located as length, width and height respectively, and with the center of the digitized dental model as the center, so as to use the surface of the cuboid as the envelope surface.

[0063] At this time, the directions of the sides of the cuboid are defined based on the local coordinate system axes of the digital dental model, which further simplifies the position expression of the cuboid in space. As a result, the amount of calculation required for subsequent smooth deformation will be smaller, further improving the processing efficiency and the efficiency of undercut filling.

[0064] In addition, the projection of the digital dental model on the coordinate axis is used as the length, width and height of the cuboid, so that the envelope surface of the cuboid can just surround the digital dental model, making the amount of subsequent smooth deformation required smaller, which is conducive to improving the deformation efficiency and then improving the efficiency of undercut filling.

[0065] Step 103, taking the digital dental model as a target, the envelope surface is smoothly deformed to obtain a target digital dental model with the undercut area filled.

[0066] It should be noted that the degree of smoothness affects the effect on the undercut area. This embodiment does not limit the specific degree of smoothness of the smooth deformation, which can be set according to actual conditions, or determined according to the size and depth of the undercut area of ​​the digital dental model.

[0067] It is understandable that, since the deformation is a smooth deformation, the envelope surface will not be sunken in the undercut area of ​​the digital dental model until the undercut area is completely fitted, but will remain smooth with the area around the undercut area, thereby presenting a state where the undercut area is filled. That is, the target digital dental model with the undercut area filled is obtained.

[0068] In order to facilitate those skilled in the art to better understand the above effects, the following will be combined with Figure 2 and Figure 5 Herein, Figure 5 According to the undercut filling method provided in this embodiment, Figure 2 After processing the digital dental model shown, the target digital dental model is obtained.

[0069] contrast Figure 2 and Figure 5 It can be seen that Figure 2 The undercut area A and undercut area B of the digital dental model are shown in Figure 5 No longer displayed in Figure 5 Zhongyu Figure 2 The areas A' and B' corresponding to the undercut areas A and B of the digital dental model shown in the figure maintain smooth changes relative to the surrounding areas, that is, the undercuts disappear after being filled.

[0070] In some embodiments, taking the digital dental model as a target, the envelope surface is smoothly deformed, which can be achieved in the following manner: the envelope surface is deformed to approximate the digital dental model and satisfy the smoothness constraint.

[0071] In other words, the deformation of the envelope surface is restricted by smoothness constraints, gradually approaching the digital dental model, so that its deformation becomes a smooth deformation.

[0072] In some embodiments, the smoothness constraint is a smoothness requirement that the envelope surface obtained after each vertex on the envelope surface moves in the process of approximating the surface of the digital dental model remains smooth.

[0073] It is understood that the digital model is actually composed of a large number of points. When the distance between these points is very small, they can be recognized by the human eye as continuous distribution. Here, in order to be consistent with the digital dental model, an envelope surface composed of several points can be provided.

[0074] It should be noted that the present embodiment does not limit the distribution of points on the envelope surface, which may be generated according to a preset rule or randomly generated, which will not be described in detail here.

[0075] That is to say, in this embodiment, each vertex on the envelope surface is used to represent the envelope surface to realize the approximation of the envelope surface to the surface of the digital dental model. The calculation of the subsequent deformation process can calculate the amount and direction of the smooth deformation through the coordinates of each vertex without calculating the data of the entire envelope surface, which is conducive to reducing the amount of data to be processed and improving the efficiency of undercut filling.

[0076] In some embodiments, the smoothness constraint is implemented by adding a preset smoothness constraint item to the target displacement of each vertex on the envelope surface approximating to the surface of the digital dental model.

[0077] This embodiment does not limit the specific expression of the preset smooth constraint item, which may be any expression that can constrain the smooth movement characteristics of each vertex on the envelope surface.

[0078] In other words, by constraining the target displacement to move smoothly before moving, rather than smoothing the uneven areas after moving, the test has fewer steps and is more efficient.

[0079] In some embodiments, the preset smoothness constraint item is a distance value between the position of the vertex to be moved and the neighborhood reference coordinate positions of each of its neighboring vertices on the envelope surface.

[0080] In other words, the smoothness constraint of each vertex is determined with reference to the vertices in the neighborhood, so that each vertex can maintain local smoothness, thereby achieving overall smoothness with lower implementation difficulty and higher efficiency.

[0081] In order to help those skilled in the art to better understand the preset smoothness constraint items involved in the above embodiments, examples are given below to illustrate them.

[0082] In some embodiments, the expression of the preset smoothness constraint term is:

[0083] D1 = neighborhood reference coordinate position - coordinate position of the vertex to be moved on the envelope surface,

[0084] Among them, D1 is the target smooth displacement of the vertex to be moved on the envelope surface, and the neighborhood reference coordinate position includes the mean of the coordinate positions of each vertex in the 1-ring neighborhood of the vertex to be moved, the median of the coordinate positions of each vertex in the 1-ring neighborhood of the vertex to be moved, the mean of the coordinate positions of each vertex in the 2-ring neighborhood of the vertex to be moved, or the median of the coordinate positions of each vertex in the 2-ring neighborhood of the vertex to be moved.

[0085] It should be noted that different digital dental models may have different smoothing requirements. Therefore, the above expression provides a 1-ring neighborhood and a 2-ring neighborhood, so that the required neighborhood can be selected according to different requirements to better meet user needs.

[0086] In some embodiments, Figure 6 As shown, with the digital dental model as the target, before the envelope surface is smoothly deformed, the method for filling the undercut also includes the following steps:

[0087] Step 104: Generate a distance field of the digital dental model.

[0088] In this embodiment, the distance field of the digital dental model can represent the closest distance to the surface of the digital dental model.

[0089] Accordingly, taking the digital dental model as the target, the envelope surface can be smoothly deformed by the following steps:

[0090] Step 1031: Determine the target deformation displacement from each vertex on the envelope surface to the surface of the digitized dental model according to the distance field of the digitized dental model.

[0091] Since the distance field of the digital dental model can represent the closest distance to the surface of the digital dental model after the distance field of the digital dental model is generated, the distance field based on the digital dental model can further accurately determine the closest distance from the envelope surface to the digital pressing surface, and the envelope surface can be precisely deformed based on the determined distance.

[0092] Step 1032: Determine the target smooth displacement of each vertex on the envelope surface according to the preset smooth constraint item.

[0093] It can be understood that the target smooth displacement provides a smooth constraint so that the subsequent movement is a smooth deformation.

[0094] Step 1033: Determine the target displacement of each vertex on the envelope surface according to the corresponding target deformation displacement and target smooth displacement.

[0095] Step 1034, moving each vertex on the envelope surface along the normal direction by a target displacement.

[0096] It is understandable that the movement along the normal direction is more efficient. That is, moving each vertex on the envelope surface along the normal direction by a target displacement can more efficiently approach the digital dental model.

[0097] Therefore, in this embodiment, the displacement of the envelope surface contraction can be determined more accurately based on the distance field calculation, and the smoothness constraint item can better ensure the smoothness of the envelope surface after the movement, thereby achieving smooth deformation.

[0098] In order to facilitate those skilled in the art to better understand the smooth deformation of the envelope surface described in the above embodiment, the following will be combined with Figure 7-9 Provide explanation.

[0099] refer to Figure 7, the vertex E on the spherical envelope surface is on the target digital dental model. With smooth deformation, it passes through the position indicated by point E' and reaches the position indicated by point E'', close to the surface of the digital dental model. The other vertices on the envelope surface are also smoothly deformed like point E, so that the envelope surface is finally as shown in Figure 7 Curve F is shown fitted to the surface of the digital dental model.

[0100] It should be noted that the curve F is only a schematic diagram to help those skilled in the art understand that the envelope surface formed by fitting on the surface of the digital dental model should be a three-dimensional structure, that is, the target digital dental model.

[0101] refer to Figure 8 and Fig. 9 , which is a simple illustration of the local cross-sectional structure of the digital dental model before and after smooth deformation. Figure 8 As shown in , before the smooth deformation begins, the teeth on the digital dental model are surrounded by the envelope surface H; Fig. 9 As shown, after the smooth deformation is completed, the envelope surface is close to the surface of the non-concave area of ​​the digital dental model, while the concave area of ​​the digital dental model is not close to the surface of the digital dental model, but is located above the concave area, thereby filling the concave area.

[0102] In some embodiments, the target displacement of each vertex on the envelope surface is determined according to the corresponding target deformation displacement and the target smooth displacement, which can be achieved by performing weighted averaging on the target deformation displacement and the target smooth displacement, and using the weighted average result as the target displacement of the corresponding vertex on the envelope surface. Thus, by performing weighted averaging on the target deformation displacement and the target smooth displacement, the degree of deformation and smoothness can be more comprehensively considered in the target displacement, thereby accurately determining the target displacement.

[0103] In some embodiments, the weight value ranges of the target deformation displacement and the target smooth displacement are both (0, 1).

[0104] That is to say, the target displacement will not obtain the complete target deformation displacement and target smooth displacement, that is, the deformation will not be completed in one go, but at least two moves will be performed, so that the target displacement of each movement can be continuously adjusted to make the smooth deformation more accurate, thereby further improving the accuracy of undercut filling.

[0105] In some embodiments, the displacement of the target deformation displacement decreases as the number of movements increases. That is, the target deformation displacement used in each movement will become smaller and smaller.

[0106] That is to say, when approaching the digital dental model by multiple moves, the envelope surface is first smoothly deformed with a larger step length so that the envelope surface can approach the surface of the digital dental model more quickly, and then the envelope surface is smoothly deformed with a smaller step length so that it can approach the surface of the digital dental model with higher accuracy after approaching the envelope surface. This has both high efficiency and high accuracy.

[0107] In some embodiments, the weight of the target smooth displacement varies with the space between teeth on the digitized dental model.

[0108] It is understandable that the size of the gap between teeth on the digital dental model will affect the degree of undercuts that need to be filled. By changing the weight of the target smooth displacement according to the gap between teeth on the digital dental model, the degree of smoothness can actually be changed with the gap between teeth on the digital dental model. In this way, the weight of the target smooth displacement changes with the gap between teeth on the digital dental model, so that the gap between teeth on the digital dental model is consistent with the degree of undercut filling, which is conducive to obtaining a better undercut filling effect.

[0109] In some examples, the larger the gap between teeth on the digital dental model, the greater the weight of the target smooth displacement.

[0110] It is understandable that the larger the gap between teeth on the digital dental model, the larger the undercut area and the deeper the filling. At this time, the smoothing requirement of the smooth deformation needs to be set higher. The larger the weight of the target smooth displacement, the more consideration will be given to the smooth deformation during the movement, and it will be easier to achieve a better smoothing effect, thereby better filling the undercut area.

[0111] In some embodiments, generating a distance field of a digitized dental model can be achieved in the following manner: generating a point cloud grid array surrounding the digitized dental model, the dimension of the point cloud grid array is l*m*n, and l, m, and n are all positive integers; respectively determining the minimum distance from each vertex in the point cloud grid array to the surface of the digitized dental model, so as to generate a distance field of the point cloud grid array relative to the digitized dental model according to the minimum distance corresponding to each vertex in the point cloud grid array.

[0112] Among them, the point cloud grid array can be Fig.10 shown.

[0113] In other words, the distance field is obtained based on the minimum distance from the points on the point cloud grid array to the surface of the digitized tooth model. It is no longer necessary to obtain spatially continuous points to generate the distance field. The generation of the point cloud grid array is simple and efficient, the data that needs to be processed is reduced, the amount of calculation is also reduced, and the efficiency is higher.

[0114] It is understandable that the points on the point cloud grid array are discrete points, which cannot represent all points in space. Therefore, the distance field generated based on the point cloud grid array cannot describe the minimum distance from all points in space to the surface of the digitized dental model. Based on this, in some embodiments, according to the distance field of the digitized dental model, the target deformation displacement from each vertex on the envelope surface to the surface of the digitized dental model is determined, which can be achieved in the following way: for each vertex on the envelope surface, the 8 closest vertices are determined on the point cloud grid array; the distance parameters of the 8 vertices in the distance field of the digitized dental model are interpolated to determine the distance parameters of the corresponding vertices on the envelope surface as the target shrinkage displacement.

[0115] Among them, since the 8 points closest to each vertex in the point cloud grid array are actually the points in the nearest neighborhood to the vertex, they can reflect the minimum distance from the area where the vertex is located to the surface of the digitized dental model, and then indent to a specific position (that is, the position of the vertex) by inserting points to obtain the minimum distance from the specific position to the surface of the digitized dental model. The obtained minimum distance is more accurate, thereby improving the accuracy of undercut filling.

[0116] It should be noted that this embodiment does not limit the interpolation method, which can be a linear difference, a high-order difference, etc., which will not be described in detail here.

[0117] In some embodiments, after moving each vertex on the envelope surface by a target displacement along the normal direction, the method for filling the undercut also includes the following steps: detecting whether the reference distance of the moved envelope surface is less than a preset threshold; if it is not less than the preset threshold, returning to the step of determining the target contraction displacement of each vertex on the envelope surface to the surface of the dental model according to the distance field of the dental model, until the reference distance of the moved envelope surface is less than the preset threshold.

[0118] Among them, the preset threshold is less than or equal to 0.05mm, and the reference distance includes the maximum distance from the vertex on the envelope surface after movement to the surface of the dental model, and / or the difference between the distance from the vertex on the envelope surface to the surface of the dental model after movement and the distance from the vertex on the envelope surface to the surface of the dental model before movement.

[0119] In other words, whether to stop the smooth deformation of the envelope surface can be determined not only based on the distance from the envelope surface to the surface of the digital dental model after the movement, but also based on whether the difference between the distance from the envelope surface to the surface of the digital dental model before and after the current smooth deformation does not exceed a preset threshold. In this way, the accuracy of the generated target digital dental model is controlled in different ways, which enriches the richness of the implementation methods of the undercut filling method, provides users with a variety of implementation methods, and is also conducive to increasing the application scenarios of the undercut filling method and improving its wide application.

[0120] In some embodiments, Fig.11 As shown, after each vertex on the envelope surface is moved along the normal direction by a target displacement, the method for filling the undercut also includes:

[0121] Step 1035 , detecting whether the moved envelope surface fits the digital dental model in the non-undercut area.

[0122] It is understandable that the smooth movement of the envelope surface is usually the overall movement of the envelope surface. When the envelope surface after the movement fits the digital dental model in the non-concave area, the envelope surface can no longer continue to deform smoothly in the non-concave area, otherwise the envelope surface will sink in the non-concave area and move away from the digital dental model, which is contrary to the goal of approaching the digital dental model. Therefore, whether the envelope surface after the movement fits the digital dental model in the non-concave area can be used as a basis to determine whether to continue to deform smoothly.

[0123] In some embodiments, detecting whether the moved envelope surface fits the digitized dental model in the non-undercut area can be achieved in the following manner: detecting whether the reference distance of the moved envelope surface is less than a preset threshold; if the reference distance of the moved envelope surface is not less than the preset threshold, confirming that the moved envelope surface does not fit the digitized dental model in the non-undercut area; wherein the preset threshold is less than or equal to 0.05 mm, and the reference distance includes the maximum distance from the vertex on the moved envelope surface to the surface of the dental model, and / or the difference between the distance from the vertex on the moved envelope surface to the surface of the dental model and the distance from the vertex on the envelope surface to the surface of the dental model before the movement.

[0124] In this embodiment, the state of the envelope surface after moving fitting to the digital dental model in the non-undercut area is defined by a preset threshold, so that it can be clearly and efficiently detected whether the envelope surface after moving fits to the digital dental model in the non-undercut area, thereby improving the accuracy and efficiency of undercut filling.

[0125] Step 1036, when the envelope surface after movement does not fit the digital dental model in the non-undercut area, return to the step of determining the target displacement of each vertex on the envelope surface to the surface of the digital dental model according to the distance field of the digital dental model, until the envelope surface after movement fits the digital dental model in the non-undercut area.

[0126] The implementation of step 1036 in this embodiment is substantially the same as the implementation of step 1033 in the aforementioned embodiment, the difference mainly lies in the specific parameters or specific values ​​of the target displacement, etc. The implementation steps are substantially the same and will not be described in detail here.

[0127] It should be noted that the value "0.05" in the above embodiment is only an example of the preset threshold value, and the specific value of the preset threshold value can actually reflect the accuracy of the undercut being filled. In some embodiments, the preset threshold value can be set to other specific values ​​according to actual needs, such as a preset threshold value of 0.5mm, or a preset threshold value of 0.0005mm, etc., which will not be described here one by one. Another embodiment of the present invention further provides a method for manufacturing a dental appliance, the process of which is as follows Fig.12 As shown, at least the following steps are included:

[0128] Step 1201, filling the undercut of the digital dental model to obtain a target digital dental model.

[0129] It should be noted that the filling of the undercut in the digital dental model is achieved according to the undercut filling method as described in any of the previous embodiments, which will not be described in detail here.

[0130] Step 1202: Generate a shell-shaped dental appliance according to the target digital dental model.

[0131] In some examples, generating a shell-shaped dental appliance according to a target digital dental model can be achieved in the following manner: manufacturing a positive mold of the appliance according to the target digital dental model; obtaining a shell-shaped dental appliance containing a tooth shape by hot pressing on the positive mold of the appliance; and cutting along the gum line or adjacent to the gum line on the shell-shaped dental appliance containing a tooth shape to obtain a shell-shaped dental appliance capable of accommodating teeth. That is, after obtaining the target digital dental model, extracting and converting data of the target digital dental model, converting the data of the target digital dental model into specification data for manufacturing the positive mold of the appliance, and then completing the manufacture of the positive mold of the appliance according to the obtained specification data, and then using a hot pressing forming device, through positive pressure film pressing technology, pressing the appliance membrane composed of a transparent polymer material (elastic polymer, such as polycarbonate) on the positive mold of the above-mentioned appliance to form a shell, thereby obtaining a shell-shaped dental appliance containing a tooth shape. The hot pressing forming method greatly improves manufacturing efficiency and accuracy. Among them, in order to make the manufactured dental appliance play a good correction role, it is necessary to ensure that the dental appliance can be used normally. Therefore, on the hot-pressed shell-shaped dental appliance, the shell-shaped dental appliance is cut along the gum line or adjacent to the gum line, so that the cut shell-shaped dental appliance can accommodate the patient's teeth, thereby completing the manufacture of the shell-shaped dental appliance.

[0132] In other examples, the generation of a shell-shaped dental appliance according to the target digital dental model can also be achieved in the following manner: generating a digital appliance model that matches the target digital dental model; and manufacturing the shell-shaped dental appliance through an additive manufacturing process according to the data information corresponding to the digital appliance model. That is, after the creation of the target digital dental model is completed, a digital appliance that includes a housing space for accommodating the target digital dental model and matches the target digital dental model is manufactured according to the target digital dental model.

[0133] Among them, in actual applications, the process of generating a digital orthodontic appliance model that matches the target digital dental model can be as follows: on the target digital dental model, a base model of the orthodontic appliance is obtained by thickening the surface; then, according to the different movement directions and amounts of each tooth, the magnitude and direction of the required correction force and torque are calculated, and the shape and size of the required local structure or accessories of the orthodontic appliance are determined according to the thermodynamic model of the shape memory polymer material, and the local structure is combined with the base model to obtain a three-dimensional digital orthodontic appliance model of the completed invisible orthodontic appliance model.

[0134] It should be noted that when a shell-shaped dental appliance is manufactured by an additive manufacturing process, rapid prototyping technology can be used for manufacturing, and the specification data of the digital appliance is converted into a data format corresponding to the rapid prototyping technology used, and then the manufacturing is completed using rapid prototyping technology. Among them, the rapid prototyping technologies used include: stereolithography (STL), stereo lithography (SLA), laminated object manufacturing (LOM), selected laser sintering (SLS), fused deposition modeling (FDM), three-dimensional printing (3DP), etc., and there is no restriction on the specific rapid prototyping technology used.

[0135] It should be noted that during the creation of a digital appliance, the auxiliary devices needed in the orthodontic process can also be considered. Based on the digital models of auxiliary devices such as auxiliary corrective devices and fasteners that need to be used, the digital appliance includes a storage space for accommodating the digital models corresponding to the auxiliary devices. The generated digital appliance includes a storage space for accommodating the target digital dental model, and may also include a storage space for accommodating the digital models corresponding to the auxiliary devices.

[0136] The step division of the above methods is only for the purpose of clear description. When implemented, they can be combined into one step or some steps can be split and decomposed 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 to the algorithm or process or introducing insignificant designs without changing the core design of the algorithm and process are all within the scope of protection of this patent.

[0137] Another aspect of the present invention is to provide an electronic device, such as Fig.13 As shown, it includes: at least one processor 1301; and a memory 1302 that is communicatively connected to the at least one processor 1301; wherein the memory 1302 stores instructions that can be executed by the at least one processor 1301, and the instructions are executed by the at least one processor 1301 so that the at least one processor 1301 can execute the method described in any of the above method embodiments.

[0138] Among them, the memory 1302 and the processor 1301 are connected in a bus manner, and the bus may include any number of interconnected buses and bridges, and the bus connects various circuits of one or more processors 1301 and the memory 1302 together. 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 are therefore not further described herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be one element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices on a transmission medium. The data processed by the processor 1301 is transmitted on a wireless medium through an antenna, and further, the antenna also receives data and transmits the data to the processor 1301.

[0139] The processor 1301 is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interfaces, voltage regulation, power management and other control functions. The memory 1302 can be used to store data used by the processor 1301 when performing operations.

[0140] Another aspect of the present invention provides a computer-readable storage medium storing a computer program, which implements the above method embodiment when executed by a processor.

[0141] That is, those skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including several instructions for making a device (which can be a single-chip microcomputer, chip, etc.) or a processor (processor) perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0142] Those skilled in the art will appreciate that the above embodiments are specific embodiments for implementing the present invention, and that in actual applications, various changes may be made in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A method for filling an undercut, characterized in that: include: Acquire a digital dental model, wherein the digital dental model has undercut areas between teeth; generating an envelope surface surrounding the digital dental model; Taking the digital dental model as a target, the envelope surface is smoothly deformed to obtain a target digital dental model in which the undercut area is filled.

2. The method for filling an undercut according to claim 1, characterized in that: The step of taking the digital dental model as a target and performing smooth deformation on the envelope surface comprises: The envelope surface is deformed to approximate the digital dental model and satisfy a smoothness constraint.

3. The method for filling an undercut according to claim 2, characterized in that: The smoothness constraint is a smoothness requirement that the envelope surface obtained after each vertex on the envelope surface moves in the process of approximating the surface of the digital dental model, remains smooth.

4. The method for filling an undercut according to claim 2, characterized in that: The smooth constraint is implemented by adding a preset smooth constraint item to the target displacement of each vertex on the envelope surface approximating the surface of the digital dental model.

5. The method for filling an undercut according to claim 4, characterized in that: The preset smoothness constraint item is a distance value between the position of the vertex to be moved on the envelope surface and the neighborhood reference coordinate positions of each of the vertices in its neighborhood.

6. The method for filling an undercut according to claim 5, characterized in that: The expression of the preset smoothness constraint term is: D1 = neighborhood reference coordinate position - coordinate position of the vertex to be moved on the envelope surface, Among them, D1 is the target smooth displacement of the vertex to be moved on the envelope surface, and the neighborhood reference coordinate position includes the mean of the coordinate positions of each vertices in the 1-ring neighborhood of the vertex to be moved, the median of the coordinate positions of each vertices in the 1-ring neighborhood of the vertex to be moved, the mean of the coordinate positions of each vertices in the 2-ring neighborhood of the vertex to be moved, or the median of the coordinate positions of each vertices in the 2-ring neighborhood of the vertex to be moved.

7. The method for filling an undercut according to claim 4, characterized in that: Before the envelope surface is smoothly deformed with the digital dental model as the target, the method further includes: generating a distance field of the digital dental model; The step of taking the digital dental model as a target and performing smooth deformation on the envelope surface comprises: Determining target deformation displacement from each vertex on the envelope surface to the surface of the digital dental model according to the distance field of the digital dental model; Determining a target smooth displacement of each vertex on the envelope surface according to the preset smooth constraint item; Determining the target displacement of each vertex on the envelope surface according to the corresponding target deformation displacement and the target smooth displacement; Each vertex on the envelope surface is moved along the normal direction by the target displacement.

8. The method for filling an undercut according to claim 7, characterized in that: Determining the target displacement of each vertex on the envelope surface according to the corresponding target deformation displacement and the target smooth displacement includes: The target deformation displacement and the target smooth displacement are weighted averaged, and a result of the weighted average is used as the target displacement of the corresponding vertex on the envelope surface.

9. The method for filling an undercut according to claim 8, characterized in that: The weight value ranges of the target deformation displacement and the target smooth displacement are both (0, 1).

10. The method for filling an undercut according to claim 8, characterized in that: The weight of the target deformation displacement decreases as the number of moves increases.

11. The method for filling an undercut according to claim 8, characterized in that: The weight of the target smooth displacement varies with the gap between teeth on the digital dental model.

12. The method for filling an undercut according to claim 7, characterized in that: The step of generating the distance field of the digital dental jaw model comprises: Generate a point cloud grid array surrounding the digital dental model, wherein the dimension of the point cloud grid array is l*m*n, where l, m, and n are all positive integers; The minimum distance from each vertex in the point cloud grid array to the surface of the digitized dental model is determined respectively, so as to generate a distance field of the point cloud grid array relative to the digitized dental model according to the minimum distance corresponding to each vertex in the point cloud grid array.

13. The method for filling an undercut according to claim 7, characterized in that: Determining the target deformation displacement from each vertex on the envelope surface to the surface of the digital dental model according to the distance field of the digital dental model includes: For each vertex on the envelope surface, determine the eight vertices closest to each other on the point cloud grid array; The distance parameters of the eight vertices in the distance field of the digital dental model are interpolated to determine the distance parameters of the corresponding vertices on the envelope surface and use them as the target contraction displacement.

14. The method for filling an undercut according to claim 7, characterized in that: After moving each vertex on the envelope surface by the target displacement along the normal direction, the method further includes: Detecting whether the reference distance of the envelope surface after the movement is less than a preset threshold; In the case where the distance is not less than the preset threshold, returning to the step of determining the target contraction displacement from each vertex on the envelope surface to the surface of the dental model according to the distance field of the dental model, until the reference distance of the envelope surface after the movement is less than the preset threshold; Among them, the preset threshold is less than or equal to 0.05mm, and the reference distance includes the maximum distance from the vertex on the envelope surface to the surface of the dental model after movement, and / or the difference between the distance from the vertex on the envelope surface to the surface of the dental model after movement and the distance from the vertex on the envelope surface to the surface of the dental model before movement.

15. The method for filling an undercut according to claim 7, characterized in that: After moving each vertex on the envelope surface by the target displacement along the normal direction, the method further includes: Detecting whether the envelope surface after the movement is fitted to the digital dental model in the non-undercut area; In the case that the envelope surface after movement does not fit the digital dental model in the non-undercut area, return to the step of determining the target displacement of each vertex on the envelope surface to the surface of the digital dental model according to the distance field of the digital dental model, until the envelope surface after movement fits the digital dental model in the non-undercut area.

16. The method for filling an undercut according to claim 15, characterized in that: The step of detecting whether the envelope surface after the movement is fitted to the digital dental model in the non-undercut area includes: Detecting whether the reference distance of the envelope surface after the movement is less than a preset threshold; When the reference distance of the envelope surface after the movement is not less than the preset threshold, confirming that the envelope surface after the movement is not attached to the digital dental model in the non-undercut area; Among them, the preset threshold is less than or equal to 0.05mm, and the reference distance includes the maximum distance from the vertex on the envelope surface to the surface of the dental model after movement, and / or the difference between the distance from the vertex on the envelope surface to the surface of the dental model after movement and the distance from the vertex on the envelope surface to the surface of the dental model before movement.

17. The method for filling an undercut according to any one of claims 1 to 16, characterized in that: The step of generating an envelope surface surrounding the digital dental model comprises: A spherical surface is generated with the center of the digital dental model as the sphere center and the maximum distance from a point on the digital dental model to the sphere center as the radius, so as to use the spherical surface as the envelope surface.

18. The method for filling an undercut according to any one of claims 1 to 16, characterized in that: The step of generating an envelope surface surrounding the digital dental model comprises: A cuboid is generated with the projections of the digitized dental model on the coordinate axes in the local coordinate system of the digitized dental model being length, width and height respectively, and the center of the digitized dental model being the center, so that the surface of the cuboid is used as the envelope surface.

19. A method for manufacturing a dental appliance, characterized in that: include: According to the undercut filling method as claimed in any one of claims 1 to 18, the undercut is filled on the digital dental model, the target digital dental model; A shell-shaped dental appliance is generated according to the target digital dental model.

20. The method for manufacturing a dental appliance according to claim 19, characterized in that: The step of generating a shell-shaped dental appliance according to the target digital dental model comprises: manufacturing a positive mold of the orthodontic appliance according to the target digital dental model; A shell-shaped dental appliance having a tooth shape is obtained by hot pressing on the male mold of the appliance; The shell-shaped dental appliance including the tooth shape is cut along the gum line or adjacent to the gum line to obtain a shell-shaped dental appliance capable of accommodating the tooth.

21. The method for manufacturing a dental appliance according to claim 19, characterized in that: The step of generating a shell-shaped dental appliance according to the target digital dental model comprises: Generating a digital orthodontic appliance model that matches the target digital dental model; According to the data information corresponding to the digital appliance model, a shell-shaped dental appliance is manufactured through an additive manufacturing process.

22. An electronic device, characterized in that: include: at least one processor; as well as, a memory communicatively connected to 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 so that the at least one processor can execute the method for filling an undercut as described in any one of claims 1 to 18, or execute the method for manufacturing a dental appliance as described in any one of claims 19 to 21.

23. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for filling an undercut as claimed in any one of claims 1 to 18 is implemented, or the method for manufacturing a dental appliance as claimed in any one of claims 19 to 21 is implemented.

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