A method for generating a cutting path of an invisible aligner and a cutting control device

Abstract

The application discloses a kind of invisible mouthguard cutting path generation method and cutting control device, it is related to flexible processing technical field, including: scanning obtains the three-dimensional digital model of patient's teeth, according to the curvature of three-dimensional digital model, gum boundary line is identified, and initial gum cutting line is extracted;Initial gum cutting line is optimized to algorithm, and selectively input interactive operation parameter is adjusted to cutting line, and cutting path data is obtained;Cutting path data is converted into executable numerical control processing code, controls mouthguard cutting machine to drive cutting tool to move, executes cutting action.The application can realize the quick, accurate automated cutting of mouthguard edge, practically improve the production efficiency and product quality of invisible mouthguard.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of flexible processing technology, in particular to a cutting path generation method and cutting control device for invisible aligners. BACKGROUND

[0002] As a modern orthodontic appliance, invisible aligners have been widely used in orthodontic treatment due to their aesthetic, comfortable and removable characteristics. Such aligners are usually made of medical-grade transparent plastic. The manufacturing process generally includes: first, obtaining a digital model of the patient's teeth through 3D scanning technology, then designing and producing a series of customized transparent aligners with the aid of computer-aided design (CAD) and computer-aided manufacturing (CAM) technology. In the final forming stage of the aligner, the edge of the pressed or 3D-printed aligner blank needs to be cut to remove excess material and form a precise edge that fits the gum line. Traditional cutting methods may rely on manual operation, which is inefficient and difficult to ensure accuracy, and may result in rough or non-compliant edges, affecting the comfort and correction effect of the patient's wear. Although there are some automated cutting devices, the control software that comes with them still has room for improvement in terms of flexibility in generating cutting paths, user-friendliness, and compatibility with small, desktop-level cutting devices.

[0003] Currently, there is a lack of a method that can intelligently extract and allow doctors to intuitively and conveniently define or adjust the gum cutting path in a visual interface, and based on this, quickly generate smooth and accurate cutting paths, while also being tightly integrated with compact numerical control devices to achieve an integrated device from 3D digital model scanning to final cutting formation. SUMMARY

[0004] Therefore, the present application provides an invisible aligner cutting path generation method and cutting control device, which solves the problems of inaccurate cutting path generation, lack of flexibility, low automation level, and difficulty in integrating small aligner cutting devices in existing aligner manufacturing technology, as well as the lack of a method that allows doctors to intuitively and conveniently define or adjust the cutting path in a visual interface, and based on this, quickly generate smooth and accurate cutting paths, and achieve an integrated device from 3D digital model scanning to final cutting formation.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] The present application mainly includes an invisible aligner cutting path generation method, which comprises the following steps: scanning and obtaining a three-dimensional digital model of the patient's teeth, identifying the gum boundary line according to the curvature of the three-dimensional digital model of the teeth, and extracting the initial gum cutting line;

[0007] The initial gingival cutting line is optimized, and interactive operation parameters are selectively input to adjust the cutting line, thus obtaining the braces cutting path data;

[0008] The braces cutting path data is converted into CNC machining code that can be executed by the braces cutting machine, which then controls the braces cutting machine to move the cutting tool and perform the cutting action.

[0009] As a further aspect of the present invention: identifying the gingival boundary line based on the curvature of the three-dimensional digital model of the teeth, and extracting the initial gingival cutting line includes:

[0010] The data range of the three-dimensional digital model of the tooth is selected based on the Z-axis, and the point cloud data that does not contain the gingival cutting line is removed to obtain the filtered three-dimensional digital model of the tooth.

[0011] In the filtered 3D digital model of teeth, data points of -Nearest Neighbor Set covariance matrix The calculation formula is as follows:

[0012] ,

[0013] in, Indicates the first Data points, Indicates the first Neighboring points, And based on the covariance matrix Calculate its corresponding eigenvalues , , covariance matrix The eigenvalues ​​satisfy the following: ,in, express eigenvalues, Represents the identity matrix;

[0014] For eigenvalues , , Sort the data, where... After sorting, the largest eigenvalue is taken as the numerator, and the formula is used: Calculate the corresponding data points The curvature of the model is obtained by considering the curvature of the model, where, when The larger the value, the more convex the local surface; the gingival boundary line is identified based on the curvature distribution.

[0015] Extract curvature value Data points exceeding a preset threshold are used to obtain the initial gingival cutting line.

[0016] As a further scheme of the present application: the optimization of the initial gum cutting line comprises:

[0017] The Alpha Shapes boundary point extraction method is used for model boundary point extraction.

[0018] Based on the extracted model boundary points, the best gum cutting line candidate points are extracted through an interactive multi-path tracking technology, the candidate point with the smallest x value among all the best gum cutting line candidate points is selected as the starting point, the best gum cutting line candidate points are gradually connected in space to form a closed curve, and the closed curve is subjected to window and order adjustable Savitzky-Golay smoothing filter processing, so as to realize the optimization of the initially extracted gum cutting line.

[0019] As a further scheme of the present application: the Alpha Shapes boundary point extraction method is used for tooth three-dimensional digital model boundary point extraction, which comprises:

[0020] The data points of the initial gum cutting line are used as model boundary candidate points.

[0021] The model boundary candidate points are constructed into a tetrahedral set by Delaunay tetrahedralization, and an Alpha radius is set, and it is judged in turn whether the circumscribed sphere radius of each tetrahedron is less than or equal to the Alpha radius.

[0022] The tetrahedrons with a circumscribed sphere radius less than or equal to the Alpha radius are retained to form a new tetrahedral set.

[0023] It is judged whether each triangular face of each tetrahedron in the new tetrahedral set simultaneously satisfies that the triangular face belongs to the face of a certain tetrahedron and is not shared by any other tetrahedron, and all the vertices of the triangular face satisfying the condition are used as the model boundary points of Alpha Shapes.

[0024] As a further scheme of the present application: the best gum cutting line candidate points are extracted through an interactive multi-path tracking technology, which comprises:

[0025] Based on the model boundary points of Alpha Shapes, a tracking starting point is selected.

[0026] A tracking space radius is set, and candidate points are selected in the tracking space.

[0027] Angle scores and distance scores are calculated for each candidate point, and the angle scores and the distance scores are weighted to obtain comprehensive scores, and the candidate points with the best comprehensive scores are selected as the best gum cutting line candidate points.

[0028] As a further scheme of the present application: the converting the aligner cutting path data into the numerical control machining code executable by the aligner cutting machine comprises:

[0029] inputting the final aligner cutting path data;

[0030] discretizing the aligner cutting path data into a plurality of line segments or circular arc segments based on the machining precision requirement of the aligner cutting machine to generate path planning data;

[0031] generating the G code instruction sequence executable by the aligner cutting machine based on the path planning data, the G code instruction sequence comprising linear interpolation G01, circular arc interpolation G02 / G03 and axial motion instruction;

[0032] post-processing the G code instruction sequence to add the initialization instruction, the tool compensation instruction and the program end instruction of the aligner cutting machine to form a complete machining program.

[0033] An aligner cutting control device adopts the aligner cutting path generation method described above to control the cutting path, comprising: a data acquisition module, a cutting path generation module, a code conversion module, a motion control module and an interactive monitoring module.

[0034] The data acquisition module is used to scan and acquire the three-dimensional digital model of the patient's teeth.

[0035] The cutting path generation module comprises an initial cutting line extraction unit and a path generation unit, the initial cutting line extraction unit is used to identify the gum boundary line according to the curvature of the three-dimensional digital model of the teeth and extract the initial gum cutting line, and the path generation unit is used to optimize the initial gum cutting line and selectively input the interactive operation parameters to adjust the cutting line to obtain the aligner cutting path data.

[0036] The code conversion module is used to convert the aligner cutting path data into the numerical control machining code executable by the aligner cutting machine.

[0037] The motion control module is used to load the numerical control machining code and control the aligner cutting machine to drive the cutting tool to move through the motion control card to execute the cutting action.

[0038] The interactive monitoring module is used to acquire the interactive operation parameters input by the doctor and visually display the state information of the cutting process and the aligner cutting machine.

[0039] As can be seen from the above technical scheme, the present application has the following advantages:

[0040] 1. The gingival cutting path can be accurately generated and executed by numerical control equipment, greatly improving the accuracy and product quality of the edge cutting of the mouthpiece, which is better than traditional manual cutting. The 3D digital model scanning is integrated into the work flow of the mouthpiece cutting forming, which improves the efficiency of the mouthpiece production and the integration degree of the mouthpiece cutting machine.

[0041] 2. An interactive operation interface is provided, and the doctor can intuitively adjust the gingival cutting path on the visual interface, which significantly reduces the learning cost and operation difficulty of the equipment, has higher automation degree and adapts to the needs and use habits of different mouthpiece production, and considers the integration with small desktop numerical control cutting equipment, which is convenient for rapid deployment and application in clinics or small processing points. BRIEF DESCRIPTION OF DRAWINGS

[0042] The drawings constituting a part of this application are used to provide further understanding of this application, the illustrative embodiments of this application and the description thereof are used to explain this application, and do not constitute improper limitation on this application.

[0043] Figure 1 The step schematic diagram of the invisible aligner cutting path generation method of the present application.

[0044] Figure 2 The three-dimensional digital model of the tooth scanned and obtained in the present embodiment.

[0045] Figure 3 The curvature distribution diagram of the three-dimensional digital model of the tooth in the present embodiment.

[0046] Figure 4 The initial gingival cutting line schematic diagram of the present embodiment.

[0047] Figure 5 The boundary point distribution schematic diagram of the Alpha Shapes model in the present embodiment.

[0048] Figure 6 The starting point selection schematic diagram of the interactive multi-path tracking in the present embodiment.

[0049] Figure 7 The result schematic diagram of the interactive multi-path tracking in the present embodiment.

[0050] Figure 8 The best gingival cutting candidate point schematic diagram in the present embodiment.

[0051] Figure 9 The progressive space connection result schematic diagram of the present embodiment.

[0052] Figure 10 The result schematic diagram of the curve smoothing processing in the present embodiment.

[0053] Figure 11is the interactive interface for the dentist to manually adjust the gingival cutting line in this embodiment.

[0054] Figure 12 is the final cutting path diagram of the mouthpiece in this embodiment.

[0055] Figure 13 is the simulation animation of the cutting process in real time in this embodiment.

[0056] Figure 14 is the schematic diagram of the cutting operation of the mouthpiece cutting machine in this embodiment.

[0057] Figure 15 is the structural schematic diagram of the mouthpiece cutting device for intelligently extracting the gingival cutting path provided in this embodiment.

[0058] Reference signs:

[0059] 11, mouthpiece blank; 12, mouthpiece cutting machine device; 01, data acquisition module; 02, cutting path generation module; 03, code conversion module; 04, motion control module; 05, interactive monitoring module. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in combination with embodiments and drawings. Herein, the illustrative embodiments of the present application and their descriptions are used to explain the present application, but not as a limitation of the present application.

[0061] Reference Figures 1 to 15 , the present embodiment provides a kind of gingival cutting path generation method and cutting control device of invisible mouthpiece. Method design runs on standard personal computer or special industrial computer. And it is communicated and controlled with a 4-axis small digital machine tool (for example, SmartCutter mouthpiece cutting machine, and its core motion control component is USB interface motion control card of USBCNC6 type of West Technology) by USB interface. The 4-axis digital machine tool system usually includes three linear motion axes X, Y, Z and a rotating shaft (A axis), to realize the accurate cutting of the complex profile of mouthpiece blank. The present application mainly extracts gingival cutting line by scanning the three-dimensional digital model of patient's teeth, and realizes the preliminary extraction of gingival cutting line according to the curvature of the model, then optimizes the gingival cutting line extracted initially by using Alpha Shapes model point extraction and interactive multi-path tracking technology and curve smoothing processing, and designs interactive interface for the dentist to adjust specific conditions, finally, the final gingival cutting path is converted into G code executable by mouthpiece cutting machine, and the cutting of mouthpiece blank is completed by motion control module, and the simulation animation of cutting process or the state information of mouthpiece cutting machine is displayed in real time on interactive interface through real-time monitoring. As shown in Figure 1 , the specific steps of the method include:

[0062] Step S1: Scan to obtain a three-dimensional digital model of the patient's teeth, identify the gingival boundary line based on the curvature of the three-dimensional digital model of the teeth, and extract the initial gingival cutting line.

[0063] The three-dimensional digital model of the teeth includes a 3D digital model of the upper molar or a 3D digital model of the lower molar. The 3D digital model is saved as an STL or TXT file. Each line of data in the file represents the X, Y, and Z coordinate values ​​of the data points in the model.

[0064] For example, a 3D digital model of a patient's lower molars is scanned, such as... Figure 2 As shown ( Figure 2 a is a schematic diagram of a 3D scan. Figure 2 (b is a top-view scanning diagram).

[0065] It should be understood that the gingival cutting line is the gingival line between the tooth and the gum, and the gingival cutting machine cuts the material along this line.

[0066] Specifically, the curvature distribution calculation process of the three-dimensional digital model of teeth in this invention is as follows:

[0067] First, the data range of the three-dimensional digital model of the teeth is selected based on the Z-axis. Data that does not include the gingival cutting line is removed to obtain the filtered three-dimensional digital model of the teeth.

[0068] Because the scanned 3D digital model of teeth contains some auxiliary data automatically generated by the software, the characteristics of these data are random and cannot be directly filtered out using qualitative methods. However, these data usually exist above or below the model. By selecting the Z-axis data range of the 3D digital model of teeth, these data can be efficiently removed, thus avoiding compromising the effectiveness of subsequent algorithms.

[0069] Then, the data points in the three-dimensional digital model of the teeth after the data range has been selected are calculated. of -Nearest Neighbor Set covariance matrix The calculation formula is as follows:

[0070] ,

[0071] in, Indicates the first Data points, Indicates the first Neighboring points, And based on the covariance matrix Calculate its corresponding eigenvalues , , covariance matrix The eigenvalues ​​satisfy the following: ,in, express eigenvalues, Represents the identity matrix;

[0072] Finally, the eigenvalues , , Sort the data, and use the largest eigenvalue as the numerator, then apply the following formula: Calculate the corresponding data points The curvature of the model is obtained by considering the curvature of the model, where... ,when A larger value indicates a more convex local surface, and the gingival boundary can be identified based on the curvature distribution; then the curvature value is extracted. Data points exceeding the preset threshold are used to complete the initial extraction of the gingival cutting line.

[0073] It should be understood that the gingival line has a significant characteristic of large curvature. Therefore, preserving the part with large curvature can effectively remove other non-gingival line parts and reduce the damage to the formation of the gingival cutting path.

[0074] For example, the curvature distribution of a 3D digital model of a patient's lower molars is calculated, such as... Figure 3 As shown ( Figure 3 'a' represents the curvature distribution at the side view angle. Figure 3 (b is a schematic diagram of the curvature distribution from a top-down view). Curvature values ​​are retained. After a significant portion, the initial gingival incision line is formed, such as... Figure 4 As shown ( Figure 4 'a' represents the gingival incision line from a side view. Figure 4 b represents the gingival incision line viewed from above.

[0075] In the above embodiment, the curvature distribution of the scanned 3D digital model is calculated, and the part with larger curvature value is retained to form the preliminary extracted gingival cutting line.

[0076] Step S2: Optimize the initial gingival cutting line and selectively input interactive operation parameters to adjust the cutting line to obtain braces cutting path data.

[0077] The optimization of the gingival cutting line involves several steps. First, model boundary points are extracted using Alpha Shapes. Then, interactive multi-path tracing technology is used to extract the optimal candidate points for the gingival cutting line. Finally, curve smoothing is applied to optimize the initially extracted gingival cutting line. The optimized gingival cutting line can be manually adjusted by the physician through an interactive interface based on the patient's actual condition.

[0078] Based on the above optimization and manual adjustment of the gingival cutting path process, the specific steps of S2 are:

[0079] A1: Alpha Shapes model boundary point extraction on the preliminary extracted gingival cutting line.

[0080] It should be understood that Alpha Shapes is a computational method for extracting shape boundaries based on a discrete point set, which reconstructs the geometric profile of an object by combining Delaunay tetrahedralization and adjustable parameters. Its core is to flexibly control the tightness of the boundary by adjusting parameters: a larger value produces a smooth boundary close to the convex hull, while a smaller value can capture more detailed concave features. This algorithm has good robustness to noisy data, high computational efficiency, and is suitable for two-dimensional and three-dimensional data, and is an effective tool for extracting meaningful shape boundaries from unordered point clouds.

[0081] Specifically, the Alpha Shapes model boundary point extraction process in the present application is as follows:

[0082] First, the data points of the preliminary extracted gingival cutting line are taken as Alpha Shapes model boundary candidate points, and stored in the candidate point set .

[0083] Then, the candidate point set is constructed into a Delaunay tetrahedralization that satisfies the empty sphere property (EmptyCircumsphere), which can be represented by the following mathematical relationship:

[0084] ,

[0085] wherein, represents each tetrahedron in , and the circumscribed sphere of does not contain any other points, is the circumscribed sphere of tetrahedron , and is the four vertices of tetrahedron .

[0086] There are the following 3 steps for constructing the Delaunay tetrahedralization:

[0087] Step 1, calculate the convex hull of the point set: find the convex hull vertices of the selected point set as the initial structure of the tetrahedralization;

[0088] Step 2, Incremental Insertion: Insert non-convex hull vertices sequentially, update the tetrahedral structure, and for each new point, find all tetrahedrons whose circumspheres contain the new point; then delete these tetrahedrons to form a star-shaped cavity; finally, fill the cavity with the new tetrahedrons to ensure that the empty sphere property is still satisfied.

[0089] Step 3, Local Optimization (Flip Algorithm): Check whether adjacent tetrahedrons satisfy the local Delaunay condition. If not, perform a flip operation (such as 2-3 flip, 3-2 flip).

[0090] It should be understood that a star-shaped cavity is a region consisting of tetrahedrons containing the new point on all circumscribed spheres, with its boundary being a topological sphere, and the new point is visible to the cavity.

[0091] Next, set the Alpha radius. (generally ), filter tetrahedrons that meet the Alpha condition. It can be expressed by the following formula:

[0092] ,

[0093] in, It is a tetrahedron The circumradius of the sphere, It is a new tetrahedron that satisfies the Alpha condition. The set of tetrahedrons, i.e., tetrahedrons whose circumscribed sphere radius is less than or equal to the Alpha radius.

[0094] For tetrahedron circumsphere radius The calculation involves the following two steps:

[0095] Step 1, for tetrahedron Calculate the center of its circumscribed ball. This can be obtained by solving the following system of linear equations:

[0096] ;

[0097] Step 2, calculate the radius of the circumscribed sphere It can be expressed by the following formula:

[0098]

[0099] Finally, boundary triangles that satisfy the following two conditions are selected. That is: (1) Boundary triangle yes (2) A face of a tetrahedron; (3) Boundary triangle It is shared by only one tetrahedron. The boundary triangle... All vertices are used as the model boundary points of Alpha Shapes.

[0100] For example, the initially extracted gingival cutting line is used to extract model boundary points using Alpha Shapes, and the result is as follows: Figure 5 As shown ( Figure 5 'a' is a schematic diagram of the boundary point extraction results from the side view angle. Figure 5 (b is a schematic diagram of the boundary point extraction results from a top-down perspective).

[0101] A2: The optimal candidate points for the gingival cutting line are extracted using interactive multi-path tracing technology.

[0102] Specifically, first select the path tracing starting point from the model boundary points of the Alpha Shapes on the visualization interface (or select it automatically).

[0103] It should be understood that while automatically selecting the starting point for multi-path tracing generally achieves the desired results, it may lead to the loss of some gingival cutting paths when the boundary points of the Alpha Shapes model are discontinuous or unevenly distributed. Manually selecting the starting point for multi-path tracing can maximize the integrity of the final gingival cutting line.

[0104] For example, the multipath tracing starting point selection result for the model boundary points of the Alpha Shapes is as follows: Figure 6 As shown ( Figure 6 a is a schematic diagram showing the selection results of the multipath tracking starting point from the side-view angle. Figure 6 b is a schematic diagram of the multipath tracing starting point selection results from a top-down perspective.

[0105] Next, for the current candidate points of multi-path tracing (When multi-path tracing is executed for the first time, the current candidate point is the starting point), within the radius Internal search candidate points It can be expressed by the following formula:

[0106] ,

[0107] in, Represents the set of model boundary points of Alpha Shapes. This represents the set of candidate points.

[0108] Then, calculate the candidate points. Angle score and distance score are calculated, and the two are weighted together to obtain a comprehensive score.

[0109] The angle scoring formula is as follows:

[0110] ,

[0111] in, Indicates the current candidate point, This represents the previous candidate point, and .

[0112] The distance scoring formula is as follows:

[0113] ,

[0114] in, and They are respectively Maximum and minimum values, .

[0115] The overall score is obtained by weighting the angle score and the distance score. It can be expressed by the following formula:

[0116] ,

[0117] in, and These represent the weights of the angle score and the distance score, respectively. In this embodiment, , .

[0118] Finally, in the multi-path search history Selecting the best candidate points for gingival cutting path It can be represented by the following formula.

[0119]

[0120] like If the tracking stops, then stop tracking.

[0121] For example, interactive multipath tracing is performed on the model boundary points of the Alpha Shapes, and the multipath tracing results are as follows: Figure 7 As shown ( Figure 7 a is a schematic diagram of the multipath tracking results from the side-view angle. Figure 7 (b is a schematic diagram of the multipath tracing results from a top-down perspective). The resulting optimal gingival incision line candidate points, such as... Figure 8 As shown ( Figure 8 a is a schematic diagram of the candidate points for the optimal gingival incision line from a side view angle. Figure 8 b is a schematic diagram of the optimal candidate points for the gingival cutting line from a top-down perspective.

[0122] A3: Curve smoothing.

[0123] Specifically, firstly, among the candidate points for the optimal gingival cutting line, the candidate point with the smallest global x-value is selected as the starting point.

[0124] Secondly, progressive spatial connections are performed. The spatial search radius of the connection points is set. Radius expansion factor and maximum spatial search radius The starting point is within the set spatial search radius. The nearest neighbor point in the space is selected and connected to it, and this process is repeated. When the spatial search radius... When the nearest point in space cannot be found, based on Expand the spatial search radius until the nearest neighbor point is found or the maximum spatial search radius is reached. This eventually forms a closed curve.

[0125] For example, the candidate points of the optimal gingival cutting path are progressively connected in space to form a closed curve, as shown in the figure. Figure 9 As shown ( Figure 9 a is a schematic diagram of a closed curve for the side view angle. Figure 9 (b is a schematic diagram of a closed curve viewed from above).

[0126] Finally, the gingival incision line was optimized by using window and adjustable-order Savitzky-Golay smoothing filtering.

[0127] Savitzky-Golay smoothing filter is a digital filtering method based on local polynomial fitting. It uses the least squares method to fit a low-order polynomial to the data within a sliding window, effectively suppressing noise while preserving high-frequency characteristics of the signal (such as peaks and inflection points). Its core principle is to approximate the data points within the window with a polynomial, replacing the center point with the fitted value. The window length (must be an odd number) and the polynomial order are key parameters. Longer windows enhance smoothness but may blur details, while higher-order polynomials can better fit complex variations but are prone to overfitting. This method is suitable for smoothing scenarios that require preserving the original signal shape. It can be expressed by the following formula:

[0128]

[0129] in, Indicates half the window length. This indicates the order of the polynomial.

[0130] For example, the gingival cutting path after applying Savitzky-Golay smoothing filtering with adjustable window size and order to the closed curve is as follows:Figure 10 Fig. 2 shows a schematic diagram of the smoothing filtering result of the side view angle, Figure 10 Fig. 3 shows a schematic diagram of the smoothing filtering result of the top view angle. Figure 10 Fig. 4 shows a schematic diagram of the path adjustment result of the side view angle. Fig. 5 shows a schematic diagram of the path adjustment result of the top view angle.

[0131] A4: The dentist adjusts the gingival cutting path according to the actual situation of the patient in the interactive interface.

[0132] For example, the software interface for the dentist to adjust the gingival cutting path in the interactive interface is shown in Fig. 6. Figure 11 Fig. 7 shows the final gingival cutting path formed after the adjustment. Figure 12 Fig. 8 shows a schematic diagram of the path adjustment result of the side view angle. Figure 12 Fig. 9 shows a schematic diagram of the path adjustment result of the top view angle. Figure 12 Based on the above embodiment, the intelligent extraction of the gingival cutting line is completed through the model boundary point extraction of Alpha Shapes, interactive multi-path tracking, curve smoothing, and personalized adjustment by the dentist, and finally the data of the cutting path of the mouthpiece is obtained.

[0133] Step S3: Convert the cutting path of the mouthpiece into numerical control machining code executable by the mouthpiece cutting machine, control the cutting tool to move with the mouthpiece cutting machine, and execute the cutting action.

[0134] The numerical control machining code includes G code. The process of converting the cutting path of the mouthpiece into G code executable by the mouthpiece cutting machine is as follows:

[0135] First, input the final cutting path data of the mouthpiece, and click “Generate G code” or the corresponding menu bar to trigger it.

[0136] Second, according to the machining accuracy requirement of the mouthpiece cutting machine, the final cutting path data of the mouthpiece is discretized into several line segments or arc segments to generate path planning data.

[0137] Then, according to the path planning data, G code executable by the mouthpiece cutting machine is generated for each discretized line segment, including straight line interpolation G01, arc interpolation G02 / G03, and axial motion instructions.

[0138]

[0139] The generated G code instruction sequence is post-processed to add a mouthpiece cutting machine initialization instruction, a tool compensation instruction, and a program end instruction. At the same time, necessary auxiliary instructions are also added, such as a program header (O), a program number (Oxxxx), a coordinate system selection (G54), a unit setting (G20 / G21), a spindle start / stop (M03 / M05), and the like. According to the set material properties or default values, a suitable feed rate (F) is matched for the G01 / G02 / G03 instruction, and the maximum speed of the movement axis of the mouthpiece cutting machine is used for the fast positioning (G00) to form a complete machining G code.

[0140] The finally generated G code is displayed in the G code editing area for user preview and can be edited and modified. The G code can be directly saved as a standard G code file (such as.nc,.gcode,.tap) or temporarily stored in the device memory and sent to the motion control module.

[0141] Because different motion control cards are used in the motion control module, the readable G code files are also different. Therefore, the generated G code can be saved in multiple file formats to adapt to different motion control cards.

[0142] The process of cutting the mouthpiece blank by the motion control module is as follows:

[0143] First, the motion control module loads the G code.

[0144] Then, according to the generated G code, the zeroing operation of the mouthpiece cutting machine is performed, and the offset of the workpiece coordinate system relative to the machine coordinate system is set through sensor signal capture or manual input.

[0145] Then, according to the generated G code, the interpolator decomposes the instruction type (fast positioning, straight line, circular arc), target coordinates / angles, and set feed rate into a series of small, time-synchronized displacement increments for the motion control card to use. The control card driving motor required pulse sequence data (including pulse number, frequency, and direction signal) is directly calculated, and the data is sent to the USB CNC6 motion control card through the USB line.

[0146] After the USB CNC6 control card receives these pulse data, the step motor or servo motor connected to the X, Y, Z, and A axes is accurately driven. The motor drives the transmission mechanism such as the lead screw and guide rail, so that the cutting tool installed on the spindle moves strictly according to the complex three-dimensional (and rotating) path defined by the generated G code. The control tool rotates at high speed (if it is a milling type cutting) and moves along the path, thereby cutting off the excess material on the mouthpiece blank to form a smooth and precise mouthpiece edge.

[0147] Real-time display of simulation animation of cutting process or state information of the dental case cutting machine on the software interface for real-time monitoring.Meanwhile, control buttons of "pause", "continue", "emergency stop" are provided to allow the operator to intervene in the cutting process. After the cutting task is completed, the operator takes out the processed dental case, and a customized contact lens with an edge meeting the design requirements is obtained.

[0148] Figure 13 The simulation animation of the cutting process is displayed on the software interface.

[0149] Figure 14 The device structure diagram of the cutting operation of the dental case cutting machine in the application is shown.

[0150] The application also provides a contact lens cutting control device, as shown in the figure. Figure 15

[0151] The device includes a data acquisition module 01, a cutting path generation module 02, a code conversion module 03, a motion control module 04, and an interactive monitoring module 05.

[0152] The data acquisition module 01 is used to acquire the 3D digital model of the upper or lower slot teeth of the patient.

[0153] The cutting path generation module 02 includes an initial cutting line extraction unit 021 and a path generation unit 022. The initial cutting line extraction unit is used to identify the gum boundary line according to the curvature of the 3D digital model and extract the initial gum cutting line. The path generation unit is used to optimize the initial gum cutting line and selectively input interactive operation parameters to adjust the cutting line to obtain dental case cutting path data.

[0154] The code conversion module 03 is used to convert the dental case cutting path data into numerical control processing code executable by the dental case cutting machine.

[0155] The motion control module 04 is used to load and execute the numerical control processing code and control the movement of the cutting tool by the motion control card to execute the cutting action and complete the cutting of the dental case blank.

[0156] The interactive monitoring module 05 is used to acquire the interactive operation parameters input by the doctor and visually display the cutting process and the state information of the dental case cutting machine.

[0157] The modules in the above invisible aligner cutting control device can be implemented by software, hardware, or a combination thereof, in whole or in part. The modules can be embedded in or independent of a processor in a computer device in hardware form, or stored in a memory in the computer device in software form, so as to be invoked and executed by the processor to perform the operations corresponding to the modules.

[0158] The present application also provides a computer device including a memory, a processor, and a computer program stored in the memory. The processor executes the computer program to implement the steps in the invisible aligner cutting path generation method embodiments. For details, refer to the method embodiments, which are not repeated here.

[0159] Further, the present application also provides a non-transitory computer readable storage medium containing instructions. For example, a memory containing instructions, which can be executed by a processor of a computer device to complete the above method. For example, the non-transitory computer readable storage medium can be a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, and an optical data storage device, etc. When the computer program is executed by the processor, the steps in the invisible aligner cutting path generation method embodiments can be implemented. For details, refer to the method embodiments, which are not repeated here.

[0160] Those skilled in the art should understand that embodiments of the present application can provide methods, systems or computer program products. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0161] The present application is described with reference to flowcharts and / or block diagrams of the method, device (system) and computer program product according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as combinations of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one flow or multiple flows and / or blocks Figure 1 The device that implements the functions specified in one block or multiple blocks.

[0162] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the Figure 1 function specified in the flow or flows and / or blocks Figure 1 of the block or blocks.

[0163] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions that are executed on the computer or other programmable apparatus provide steps for implementing the Figure 1 function specified in the flow or flows and / or blocks Figure 1 of the block or blocks.

[0164] It should be noted that the above-mentioned detailed implementation can make those skilled in the art more fully understand the present application, but in no way limit the present application. Therefore, although the present application has been described in detail in the present specification and examples, those skilled in the art should understand that the present application can still be modified or replaced by equivalents; and all technical solutions and improvements which do not deviate from the spirit and scope of the present application are covered in the protection scope of the present application. Any reference signs in the claims should not be considered as limiting the claims. Simple changes or equivalent replacements of technical solutions which are obvious to those skilled in the art within the scope of the present disclosure are all within the protection scope of the present application.

Claims

1. A method for generating cutting paths for invisible braces, characterized in that, include: A three-dimensional digital model of the patient's teeth is obtained by scanning. The gingival boundary line is identified based on the curvature of the three-dimensional digital model of the teeth, and the initial gingival cutting line is extracted. The initial gingival cutting line is optimized, and interactive operation parameters are selectively input to adjust the cutting line, thus obtaining the braces cutting path data; The braces cutting path data is converted into CNC machining code that can be executed by the braces cutting machine, which controls the braces cutting machine to move the cutting tool and perform the cutting action; The optimization of the initial gingival incision line includes: The Alpha Shapes boundary point extraction method was used to extract the model boundary points. Based on the extracted model boundary points, the optimal gingival cutting line candidate points are extracted through interactive multi-path tracing technology. The candidate point with the smallest x-value among all the optimal gingival cutting line candidate points is selected as the starting point. The optimal gingival cutting line candidate points are progressively connected in space to form a closed curve. The closed curve is then subjected to Savitzky-Golay smoothing filtering with adjustable window and order to optimize the initially extracted gingival cutting line. Boundary point extraction of a 3D digital tooth model using the Alpha Shapes boundary point extraction method includes: Use the data points of the initial gingival cutting line as candidate points for the model boundary; For the candidate boundary points of the model, construct Delaunay tetrahedrons to form a tetrahedron set, and set an Alpha radius. Then, determine whether the circumscribed sphere radius of each tetrahedron is less than or equal to the Alpha radius. Retain tetrahedrons whose circumscribed sphere radius is less than or equal to the Alpha radius to form a new set of tetrahedrons; Determine whether each triangular face of each tetrahedron in the new tetrahedron set simultaneously satisfies that the triangular face belongs to a certain tetrahedron and is not shared by any other tetrahedron, and use all vertices of the triangular face that satisfies the condition as the model boundary points of Alpha Shapes. The extraction of optimal candidate points for gingival incision lines using interactive multi-path tracing technology includes: Based on the model boundary points of the Alpha Shapes, select the tracking start point; Set the radius of the tracking space, and select candidate points within the tracking space; Each candidate point is scored for both angle and distance. The angle and distance scores are then weighted to obtain a comprehensive score. The candidate point with the best comprehensive score is selected and chosen as the optimal gingival incision line candidate point.

2. The method for generating the cutting path for invisible braces according to claim 1, characterized in that, Identifying the gingival boundary line based on the curvature of the three-dimensional digital model of the teeth, and extracting the initial gingival cutting line, includes: The data range of the three-dimensional digital model of the tooth is selected based on the Z-axis, and the point cloud data that does not contain the gingival cutting line is removed to obtain the filtered three-dimensional digital model of the tooth. In the filtered 3D digital model of teeth, data points of -Nearest Neighbor Set covariance matrix , ， in, Indicates the first Data points, Indicates the first Neighboring points, And based on the covariance matrix Calculate its corresponding eigenvalues , , covariance matrix The eigenvalues ​​satisfy the following: ,in, express eigenvalues, Represents the identity matrix; For eigenvalues , , Sort the data, where... And according to the formula: Calculate the corresponding data points The curvature of the model is obtained by considering the curvature of the model, where, when The larger the value, the more convex the local surface; the gingival boundary line is identified based on the curvature distribution. Extract curvature value Data points exceeding a preset threshold are used to obtain the initial gingival cutting line.

3. The method for generating the cutting path for invisible braces according to claim 1, characterized in that, Converting the brace cutting path data into CNC machining code executable by the brace cutting machine includes: Input the final braces cutting path data; Based on the processing accuracy requirements of the brace cutting machine, the brace cutting path data is discretized into several line segments or arc segments to generate path planning data; Based on path planning data, a sequence of G-code instructions that can be executed by the braces cutting machine is generated. The sequence of G-code instructions includes linear interpolation, circular interpolation, and axial movement instructions. Post-process the G-code instruction sequence to add initialization instructions for the dental brace cutting machine, tool compensation instructions, and program termination instructions to form a complete machining program.

4. A cutting control device for invisible braces, comprising controlling the cutting path using the invisible braces cutting path generation method as described in any one of claims 1-3, characterized in that, include: The module includes a data acquisition module, a cutting path generation module, a code conversion module, a motion control module, and an interactive monitoring module. The data acquisition module is used to scan and acquire a three-dimensional digital model of the patient's teeth; The cutting path generation module includes an initial cutting line extraction unit and a path generation unit. The initial cutting line extraction unit is used to identify the gingival boundary line according to the curvature of the three-dimensional digital model of the teeth and extract the initial gingival cutting line. The path generation unit is used to optimize the initial gingival cutting line and selectively input interactive operation parameters to adjust the cutting line to obtain braces cutting path data. The code conversion module is used to convert the brace cutting path data into CNC machining code that can be executed by the brace cutting machine; The motion control module is used to load CNC machining code and control the dental brace cutting machine to move the cutting tool and perform the cutting action through the motion control card. The interactive monitoring module is used to obtain the interactive operation parameters input by the doctor and to visualize the cutting process and the status information of the braces cutting machine.

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