Method for automatically generating cutting lines of a dental aligner model, storage medium and electronic device

Abstract

The present application relates to a kind of methods for automatically generating dental case model cutting line based on dental cavity line and eruption cap accessory, mainly by means of traditional graphics geometry algorithm, adjacent dental cavities are connected by selecting control points using eruption cap accessory and the intersection of teeth and gums produces dental cavity line, the control points are fine tuned according to the characteristics of teeth and gums at different tooth positions, then the connection curve is generated according to the control points to connect two adjacent dental cavities, and finally the cutting curve of each section is integrated to generate the entire cutting line. The cutting line obtained by this method can consider various scenarios including small teeth that will erupt or have not erupted, can more greatly avoid patient discomfort caused by dental case pressing gums or small teeth, and can realize more complete cutting line generation automation, greatly saving manpower and material resources to a certain extent.

Description

Technical Field

[0001] This invention relates to the field of digital oral technology, and in particular to a method, storage medium, and electronic device for automatically generating cutting lines for a braces model based on cavity lines and eruption cap attachments. Background Technology

[0002] With the continuous development of computer graphics, invisible orthodontic technology based on digital modeling has been widely used. The production process of invisible braces mainly includes 3D printing of dental models, molding, cutting of the braces, and polishing. The key to the entire production process lies in how to cut the braces so that they can perfectly fit the patient's teeth and prevent scratching the gums. Cutting the braces is mainly based on the cutting lines obtained from the three-dimensional dental model. The cutting lines are used to separate the gums from the teeth in the model. The integrity of the separated braces and their fit with the patient's teeth depend on the quality of the cutting lines.

[0003] Currently, most commonly used methods for generating cutting lines rely on manual cutting, resulting in poor quality and stability of the generated cutting lines. Furthermore, batch generation is not possible and requires significant manpower and resources. Therefore, several techniques for automatically generating cutting lines have emerged in current research, such as those based on curvature and those based on the shortest path between two teeth's cavities. However, curvature-based methods are prone to misidentification and require manual adjustments, while shortest path-based methods can easily lead to overcutting of the model, also requiring manual adjustment or even regeneration. These methods cannot achieve complete automation of braces and do not consider the eruption of small teeth in children. Generating cutting lines using methods for normal teeth can compress erupting teeth, causing discomfort to the patient. Summary of the Invention

[0004] The technical problem to be solved by this invention is to design a method for automatically generating cutting lines for braces models. The method uses eruption cap attachments and the dentition lines generated by the intersection of teeth and gums to select connection control points between adjacent dentitions. The control points are fine-tuned according to the characteristics of teeth and gums at different tooth positions. Then, a connection curve is generated based on the control points to connect two adjacent dentitions. Finally, the cutting curves of each segment are integrated to generate the entire cutting line, thus solving the existing technical problems.

[0005] To solve the above-mentioned technical problems, the method for automatically generating braces model cutting lines of the present invention is based on the cavity line and eruption cap attachment, and specifically includes the following steps:

[0006] Step S1: Obtain the virtual tooth hole line of the cute hat accessory;

[0007] Step S2: Determine the eruption of the triangular teeth on the lingual side of the cap labium;

[0008] Step S3: Merge the eruption cap attachment and its adjacent undercut grids into the entire dentition grid;

[0009] Step S4: Traverse the tooth positions to construct labial and lingual incision lines;

[0010] Step S5: Smooth the entire cutting line;

[0011] Step S6: Filter duplicate points: Filter out duplicate points in the cutting line points after smoothing in step S5;

[0012] Step S7: Improve the curve: Further improve the cutting curve by moving the generated cutting line outward by a corresponding distance according to the input offset parameter (unit: mm) to obtain the moved point. Smooth the generated point to obtain a control line that can be applied to automatic cutting equipment.

[0013] Furthermore, step S1 includes the following steps:

[0014] Step S11: Traverse all tooth data by tooth position, mark whether the cavity of the current tooth position has an eruption cap attachment, and if there are multiple eruption caps for the current tooth position, merge the multiple eruption caps into one grid.

[0015] Step S12: Obtain the initial eruption cap tooth cavity line, ensuring that the eruption cap tooth cavity line on the labial and lingual sides is 0.1mm to 0.5mm higher than the lowest point of the edge of the adjacent cavity lines on both sides;

[0016] Step S13: Based on the initial cavity line of the eruption cap obtained in Step S12, determine the type of the eruption cap tooth: determine whether it is an external arch tooth by judging the spatial relationship between the cavity line of the eruption cap and the actual cavity line. If the current eruption cap is a non-external arch tooth, determine whether it is an eruption cap repaired decayed tooth by judging the wrapping of the cavity line of the eruption cap and the cavity line of the normal tooth. If the current tooth position is an eruption cap repaired decayed tooth, directly intersect the mesh after merging the eruption cap and the decayed tooth with the gingival mesh to obtain a new cavity line, and at the same time set the generation method of the current tooth position non-eruption cap, i.e., decayed tooth; if the current eruption cap is an external arch tooth, directly use the cavity line of the eruption cap.

[0017] Step S14: Update the local coordinate system of the eruption cap: Based on the initial local coordinate system of the adjacent denture teeth (X points to the mesial direction, Z axis points to the root growth direction), the average value of each small coordinate of the teeth on both sides can be obtained to obtain the average vector of the X, Y, and Z axes, which is used as the local coordinate system of the eruption cap.

[0018] Step S15: Partitioning the eruption cap cavity line: Based on the updated X and Y directions of the eruption cap, obtain the starting points of the four quadrants of the eruption cap cavity. That is, project the points on the eruption cap cavity line onto the straight lines of the X and Y axes, find the maximum and minimum projection points in the two directions as the starting points of the quadrants, and divide the cavity line into four quadrants based on the starting points of the quadrants. The storage order of the points in different quadrants is different. The starting points of the quadrants in the X direction are the initial points of each quadrant, and the points in the Y direction are the end points of each quadrant. When dividing the points in each quadrant, it is necessary to store the points of each quadrant according to the clockwise and counterclockwise directions of the original cavity points. Among them, quadrants 0 and 1 are the two quadrants on the labial side, and quadrants 2 and 3 are the two quadrants on the lingual side.

[0019] Step S16: The cavity points in quadrants 0 and 1 on the labial side and quadrants 2 and 3 on the lingual side are adjusted again along the z-axis based on the lowest point of the cavity line of the adjacent teeth on each side, so that the eruption cap cavity point in each quadrant is 0.1mm to 0.5mm higher than the lowest point on both sides.

[0020] Step S17: Store all eruption cap accessories except for rotten teeth.

[0021] Furthermore, in step S12, the method of obtaining the eruption cap cavity line is divided into boundary tooth eruption caps and non-boundary tooth eruption caps depending on the tooth position. For boundary tooth eruption caps, the eruption cap cavity line is intercepted by constructing a plane using the center point of the cavity line of the normal tooth at the current tooth position and the Z-axis direction of the jaw (the eruption cap of the molar is 0.1mm higher than the bottom edge of the cavity lines of the teeth on both sides). For non-boundary tooth eruption caps, the small coordinates of the current eruption cap are determined according to the coordinate directions of the non-eruption cap teeth on both sides, and the cavity line is intercepted by constructing a plane using the local Z-axis and the center point of the moved eruption cap cavity line. If the intercepted cavity line is too small, the eruption cap cavity line is re-intercepted based on the plane fitted by the cavity line of the small tooth.

[0022] Furthermore, in step S13, the method for determining an externally erupting tooth is as follows: if the distance between the center points of the two cavity lines is greater than 2.5 mm and the angle between the normals of the planes fitted by the two cavities is greater than 40°, then the current eruption cap can be determined as an externally erupting tooth; the method for determining a tooth with an eruption cap for repair is as follows: project both cavity lines onto the same plane, construct rays from the center point of the cavity line to each point on the actual cavity line, and project the points on the eruption cap cavity line onto each ray. If the distance from the projection point on the eruption cap cavity line to the center point of the actual cavity is less than the distance from the point on the actual cavity line to the center point, then it can be determined that the point on the actual cavity line is outside the projection point of the eruption cap cavity. If it is not outside, it is not recorded. If the number of points outside the eruption cap is greater than 1 / 8 of the number of points on the actual cavity, then it proves that the current tooth position is a tooth with an eruption cap for repair.

[0023] Furthermore, the method for determining the labial and lingual triangular teeth that have erupted in step S2 is as follows:

[0024] Lingual eruption of triangular teeth: Obtain the two points A and B closest to the lingual side on the 2nd and 3rd quadrants of the adjacent lingual cavities on the left and right sides. Compare these two points with the point C closest to the lingual side on the lingual cavity line of the eruption cap. Project points A, B, and C onto a ray constructed with point C and the Y-axis vector (labial-lingual direction) of the current tooth position. The starting point of this ray is point C, and the ray direction is the Y-axis direction. If the distance between the projection points of points A and B on the ray and point C is greater than 2mm, and the two projection points are closer to the lingual side than point C, then the current tooth can be determined to be a triangular tooth.

[0025] The method for determining labial eruption of triangular cusps is the same as that for lingual eruption. It is also based on the degree of concavity of the dental cavity line in the Y-axis direction. That is, the points closest to the labial side on the current dental cavity line and the adjacent two dental cavity lines are projected onto a ray constructed along the Y-axis direction with the point closest to the labial side on the current dental cavity line as the starting point, and C1, A1, and B1 are obtained respectively. The distance between the three points is compared. If the distance between the projection points of points B1 and A1 on the ray and point C1 is greater than 2mm and the two projection points are closer to the labial side than point C1, then the current tooth can be determined to be a labial triangular cusps.

[0026] Furthermore, step S3 includes the following steps:

[0027] Step S31: Obtain the inverted mesh adjacent to the budding cap;

[0028] Step S32: Merge the eruption cap attachment obtained in step S1 and the undercut grid block obtained in step S31 onto the dental grid.

[0029] Furthermore, step S4 includes the following steps:

[0030] Step S41: Detect whether the current tooth being traversed is a head tooth, i.e. a boundary tooth position. If it is a boundary tooth position, directly store the points in the 0th and 3rd quadrants of the current tooth position as cutting line points in point set A, as partial initial points for generating cutting lines. If it is not a boundary tooth position, execute steps S42-S44.

[0031] Step S42: Based on the judgment result in step S2, determine whether the currently traversed tooth is a triangular tooth.

[0032] If it is a labial triangular tooth, the jump connection is achieved from the lingual side: obtain the nearest point of the lingual grid of the gingiva below the current tooth position, find the two nearest points on the adjacent cavity quadrant as low control points, and finely adjust them 0.5mm to 1.5mm towards the center of the two control points; find the nearest point from the low control point to the cavity line, and record the corresponding cavity point indices IndexLeft and IndexRight as the jump connection position; based on the obtained low control points, take two cavity points along the labial direction of the cavity line as high control points, and finely adjust them 0.5mm to 1.5mm towards the center of the two control points; based on the four control points, use the Bezier Curve to construct the cavity connection curve, and connect the cavity lines on both sides of the triangular tooth at the jump index point. The projection direction of the connection curve is the average normal direction of the cavity construction plane on both sides.

[0033] If it is a lingual triangular tooth, the jump connection is achieved from the labial side: based on the set jump distance between adjacent cavities, the low control point is obtained, and the high control point is obtained using affine transformation; the cavity connection curve is constructed using BezierCurve, and the cavity lines on both sides of the triangular tooth are connected at the jump index point. The projection direction of the connection curve is the average normal direction of the cavity construction plane on both sides.

[0034] Step S43: Divide the cutting line into two parts, the labial and lingual sides, and generate them accordingly:

[0035] Labial cutting line: Based on the different attributes of two adjacent cavities, it can be divided into four cases: ① The left normal tooth is currently erupting; ② The left erupting tooth is currently a normal tooth; ③ The left erupting tooth is currently an erupting tooth; ④ Both the left side and the current tooth position are normal teeth. For cases ① and ②, firstly, obtain the low-level control point based on the jump distance, and then obtain the high-level control point using affine transformation. Based on the obtained control points, construct a Bezier Curve, interpolate on the curve, and project the interpolation points along the average normal direction of the three nearest mesh faces to obtain the projection points on the corresponding mesh; obtain the left and right... The lateral cavity line and projection point are obtained, and 10 points extending before and after the cavity point are obtained as the original fitting points. Fourth-order polynomial fitting is performed. The fitted points are projected according to the average normal direction of the nearest face, and points falling inside the cavity and points of excessively curved curves are removed. For case ③, there is no need to construct connecting lines to directly connect the eruption cap cavities. For case ④, firstly, the low-position control point is obtained according to the jump distance, and the high-position control point is obtained using affine transformation. Based on the obtained control points, a Bezier Curve is constructed, and interpolation is performed on the curve to connect the cavity lines of the normal teeth on both sides.

[0036] Lingual cutting lines: Similarly, lingual cutting lines can also be divided into four types, and the method for generating cutting lines is the same as that for generating labial cutting lines.

[0037] Step S44: Detect whether the current tooth is a tail boundary tooth position. If it is a tail boundary tooth position, the 0th and 3rd quadrant tooth cavity lines of the current tooth cavity are directly stored as cutting line points in point set A as partial initial points for generating cutting lines.

[0038] Furthermore, step S5 includes the following steps:

[0039] Step S51: Traverse the initial point of the cutting line, calculate the curvature of the circumcircle of the triangle constructed by each point and its two adjacent points, and the angle between the point and its two adjacent points. The angle range of the returned point is [0, 180°).

[0040] Step S52: Traverse the initial point of the cutting line. Determine whether smoothing is needed based on the circumcircle curvature and angle of each point obtained in step S51. If the difference between the circumcircle curvature of the traversed point and the points on the left and right sides is twice the difference between the curvature of the left point and its left adjacent point or twice the difference between the curvature of the right point and its adjacent point, and the current traversed point or the points before and after it are all cutting points of the erupting cap tooth position, then perform the smoothing operation. Alternatively, if the angle between the current point and the points on both sides is ≤165°, and the current point or the five points before and after it are marked as cutting points of the erupting cap tooth position, then perform the smoothing operation on the current traversed point and the two points before and after it. The smoothing mainly involves evenly distributing the five selected points on the straight line connecting the initial and end points.

[0041] The present invention also provides an electronic device, comprising:

[0042] At least one processor; and

[0043] At least one memory communicatively connected to the processor;

[0044] The memory stores instructions that can be executed by a processor, which, when executed by the processor, causes the electronic device to perform the aforementioned method for automatically generating cutting lines for a braces model.

[0045] The present invention also provides a computer-readable storage medium storing computer-executable instructions thereon, which, when executed by a processor, implement the aforementioned method for automatically generating cutting lines for a braces model.

[0046] The beneficial effects of this invention are:

[0047] The method for automatically generating braces model cutting lines based on cavity lines and eruption cap attachments of this invention mainly utilizes traditional graphic geometry algorithms. It selects connection control points between adjacent cavities using the cavity lines generated by the intersection of the eruption cap attachment and the teeth with the gingiva. These control points are then fine-tuned according to the characteristics of the teeth and gingiva at different tooth positions. Subsequently, a connection curve is generated based on the control points to connect two adjacent cavities. Finally, the cutting curves of each segment are integrated to generate the entire cutting line. The cutting lines obtained through this method can consider various scenarios, including teeth that are about to erupt or have not yet erupted, thus greatly reducing patient discomfort caused by braces pressing on the gums or small teeth. Furthermore, it achieves more complete automation in cutting line generation, significantly saving manpower and resources to a certain extent. Attached Figure Description

[0048] The specific embodiments of the present invention will be further explained below with reference to the accompanying drawings.

[0049] Figure 1 This is a flowchart of the method for automatically generating cutting lines for a braces model according to the present invention;

[0050] Figure 2 A diagram showing the intermediate results of the cutting lines for the sprouting of the hat;

[0051] Figure 3 A schematic diagram of the cutting lines for the normal emergence of the cap;

[0052] Figure 4 A diagram illustrating the cutting lines for the eruption of a cap from a decayed tooth;

[0053] Figure 5 A schematic diagram of the cutting line for the eruption cap of the external arch teeth;

[0054] Figure 6 A schematic diagram of the cutting lines for the eruption of the triangular tooth cap. Detailed Implementation

[0055] Example 1

[0056] Combination Figure 1 The method for automatically generating cutting lines for braces models in this embodiment is based on cavity lines and eruption cap attachments, and specifically includes the following steps:

[0057] Step S1: Obtain the virtual tooth hole lines of the cute hat accessory, including the following steps:

[0058] Step S11: Traverse all tooth data by tooth position, mark whether the tooth cavity of the current tooth position has an eruption cap attachment. If the current tooth position has an eruption cap, set the tooth cavity attribute m_EmergentHat=true. If the current tooth position has multiple eruption caps, merge the multiple eruption caps into one grid.

[0059] Step S12: Obtain the initial eruption cap tooth cavity line, ensuring that the eruption cap tooth cavity line on the labial and lingual sides is 0.1mm to 0.5mm higher than the lowest point of the edge of the adjacent cavity lines on both sides;

[0060] In step S12, the method for obtaining the eruption cap cavity line varies depending on the tooth position, and is divided into boundary tooth eruption caps and non-boundary tooth eruption caps. For boundary tooth eruption caps, the eruption cap cavity line is cut by constructing a plane using the center point of the cavity line of the normal tooth at the current position and the Z-axis direction of the jaw (the eruption cap of the molar is 0.1mm higher than the bottom edge of the cavity lines of the teeth on both sides). For non-boundary tooth eruption caps, the small coordinates of the current eruption cap are determined according to the coordinate directions of the non-eruption cap teeth on both sides, and the cavity line is cut by constructing a plane using the local Z-axis and the center point of the moved eruption cap cavity line. If the cut cavity line is too small, the eruption cap cavity line is cut again based on the plane fitted by the cavity line of the small tooth.

[0061] Step S13: Based on the initial cavity line of the eruption cap obtained in Step S12, determine the type of the eruption cap tooth: determine whether it is an external arch tooth by judging the spatial relationship between the cavity line of the eruption cap and the actual cavity line. If the current eruption cap is a non-external arch tooth (m_EmergentWithExArch = false), determine whether it is an eruption cap repaired decayed tooth by judging the wrapping of the cavity line of the eruption cap and the cavity line of the normal tooth. If the current tooth position is an eruption cap repaired decayed tooth, directly intersect the mesh after merging the eruption cap and the decayed tooth with the gingival mesh to obtain a new cavity line, and at the same time set the current tooth position to non-eruption cap (m_EmergentHat = false), i.e., the method of generating decayed teeth; if the current eruption cap is an external arch tooth, directly use the cavity line of the eruption cap; the stage results of the eruption cap cutting line are as follows. Figure 2 As shown, Figure 2 The order from top to bottom is: generating the eruption cap cavity line, generating the cutting connection line based on the cavity line, and generating the complete cutting connection line; a schematic diagram of the cutting line for a normal eruption cap is shown below. Figure 3 As shown.

[0062] In step S13, the determination method for external eruption teeth is as follows: if the distance between the center points of the two tooth cavity lines is greater than 2.5mm and the included angle between the normals of the fitted planes of the two tooth cavities is greater than 40°, then the current eruption cap can be determined as an external eruption tooth, and m_EmergentWithExArch = true is set. The cutting line generated for the external eruption tooth is as follows: Figure 5As shown; the method for determining whether an eruption cap is needed to repair a decayed tooth is as follows: Project both cavity lines onto the same plane. Construct rays from the center point of the cavity line to each point on the actual cavity line. Project the points on the eruption cap cavity line onto each ray. If the distance from the projected point on the eruption cap cavity line to the center point of the actual cavity is less than the distance from the point on the actual cavity line to the center point, then the point on the actual cavity line is located outside the projection point of the eruption cap cavity. If it is not outside, it is not recorded. If the number of points located outside the eruption cap is greater than 1 / 8 of the number of points on the actual cavity, then the current tooth position is a cavity for eruption cap repair, and set m_EmergFixedRotten = true. The cutting line generated for the decayed tooth is as follows. Figure 4 As shown, Figure 4 The central cutting line falls on the grid of undercuts, eruption caps, and dentition structures.

[0063] Step S14: Update the local coordinate system of the eruption cap: Based on the initial local coordinate system of the adjacent denture teeth (X points to the mesial direction, Z axis points to the root growth direction), the average value of each small coordinate of the teeth on both sides can be obtained to obtain the average vector of the X, Y, and Z axes, which is used as the local coordinate system of the eruption cap.

[0064] Step S15: Partitioning the eruption cap cavity line: Based on the updated X and Y directions of the eruption cap, obtain the starting points of the four quadrants of the eruption cap cavity. That is, project the points on the eruption cap cavity line onto the straight lines of the X and Y axes, find the maximum and minimum projection points in the two directions as the starting points of the quadrants, and divide the cavity line into four quadrants based on the starting points of the quadrants. The storage order of the points in different quadrants is different. The starting points of the quadrants in the X direction are the initial points of each quadrant, and the points in the Y direction are the end points of each quadrant. When dividing the points in each quadrant, it is necessary to store the points of each quadrant according to the clockwise and counterclockwise directions of the original cavity points. Among them, quadrants 0 and 1 are the two quadrants on the labial side, and quadrants 2 and 3 are the two quadrants on the lingual side.

[0065] Step S16: The cavity points in quadrants 0 and 1 on the labial side and quadrants 2 and 3 on the lingual side are adjusted again along the z-axis based on the lowest point of the cavity line of the adjacent teeth on each side, so that the eruption cap cavity point in each quadrant is 0.1mm to 0.5mm higher than the lowest point on both sides.

[0066] Step S17: Store all eruption cap accessories except for rotten teeth.

[0067] Step S2: Determine the eruption of the triangular teeth on the labial and lingual sides of the cap. A diagram illustrating the cutting line of the triangular teeth erupting from the cap is shown below. Figure 6 As shown, the specific determination method is as follows:

[0068] Lingual eruption of triangular teeth: Obtain the two points A and B closest to the lingual side on the 2nd and 3rd quadrants of the adjacent lingual cavities on the left and right sides. Compare these two points with the point C closest to the lingual side on the lingual cavity line of the eruption cap. Project points A, B, and C onto a ray constructed with point C and the Y-axis vector (labial-lingual direction) of the current tooth position. The starting point of this ray is point C, and the ray direction is the Y-axis direction. If the distance between the projection points of points A and B on the ray and point C is greater than 2mm, and the two projection points are closer to the lingual side than point C, then the current tooth can be determined to be a triangular tooth.

[0069] The method for determining labial eruption of triangular cusps is the same as that for lingual eruption. It is also based on the degree of concavity of the dental cavity line in the Y-axis direction. That is, the points closest to the labial side on the current dental cavity line and the adjacent two dental cavity lines are projected onto a ray constructed along the Y-axis direction with the point closest to the labial side on the current dental cavity line as the starting point, and C1, A1, and B1 are obtained respectively. The distance between the three points is compared. If the distance between the projection points of points B1 and A1 on the ray and point C1 is greater than 2mm and the two projection points are closer to the labial side than point C1, then the current tooth can be determined to be a labial triangular cusps.

[0070] The method for determining whether a normal tooth is a labial triangular tooth differs from the method for determining whether a labially erupting cap triangular tooth is a triangular tooth. For normal teeth, the method uses points on the gingival grid below the dentition line to fit the gingival periphery curve. The degree of concavity of the gingival periphery curve of each tooth position relative to the adjacent tooth positions is used to determine whether the labial tooth is a triangular tooth.

[0071] Step S3: Merge the eruption cap attachment and its adjacent undercut grids into the entire dentition grid, specifically including the following steps:

[0072] Step S31: Obtain the inverted mesh adjacent to the budding cap;

[0073] Step S32: Merge the eruption cap attachment obtained in step S1 and the undercut grid block obtained in step S31 onto the dental grid.

[0074] Step S4: Construct labial and lingual incision lines by traversing the tooth positions, specifically including the following steps:

[0075] Step S41: Detect whether the current tooth being traversed is a head tooth, i.e. a boundary tooth position. If it is a boundary tooth position, directly store the points in the 0th and 3rd quadrants of the current tooth position as cutting line points in point set A, as partial initial points for generating cutting lines. If it is not a boundary tooth position, execute steps S42-S44.

[0076] Step S42: Based on the judgment result in step S2, determine whether the currently traversed tooth is a triangular tooth.

[0077] If it is a labial triangular tooth, the jump connection is achieved from the lingual side: obtain the nearest point of the lingual grid of the gingiva below the current tooth position, find the two nearest points on the adjacent cavity quadrant as low control points, and finely adjust them 0.5mm to 1.5mm towards the center of the two control points; find the nearest point from the low control point to the cavity line, and record the corresponding cavity point indices IndexLeft and IndexRight as the jump connection position; based on the obtained low control points, take two cavity points along the labial direction of the cavity line as high control points, and finely adjust them 0.5mm to 1.5mm towards the center of the two control points; based on the four control points, use BezierCurve to construct the cavity connection curve, and connect the cavity lines on both sides of the triangular tooth at the jump index point. The projection direction of the connection curve is the average normal direction of the cavity construction plane on both sides.

[0078] If it is a lingual triangular tooth, the jump connection is achieved from the labial side: based on the set jump distance between adjacent cavities, the low control point is obtained, and the high control point is obtained using affine transformation; the cavity connection curve is constructed using BezierCurve, and the cavity lines on both sides of the triangular tooth are connected at the jump index point. The projection direction of the connection curve is the average normal direction of the cavity construction plane on both sides.

[0079] Step S43: Divide the cutting line into two parts, the labial and lingual sides, and generate them accordingly:

[0080] Labial cutting line: Based on the different attributes of two adjacent cavities, it can be divided into four cases: ① The left normal tooth is currently erupting; ② The left erupting tooth is currently a normal tooth; ③ The left erupting tooth is currently an erupting tooth; ④ Both the left side and the current tooth position are normal teeth. For cases ① and ②, firstly, obtain the low-level control point based on the jump distance, and then obtain the high-level control point using affine transformation. Based on the obtained control points, construct a Bezier Curve, interpolate on the curve, and project the interpolation points along the average normal direction of the three nearest mesh faces to obtain the projection points on the corresponding mesh; obtain the left and right... The lateral cavity line and projection point are obtained, and 10 points extending before and after the cavity point are obtained as the original fitting points. Fourth-order polynomial fitting is performed. The fitted points are projected according to the average normal direction of the nearest face, and points falling inside the cavity and points of excessively curved curves are removed. For case ③, there is no need to construct connecting lines to directly connect the eruption cap cavities. For case ④, firstly, the low-position control point is obtained according to the jump distance, and the high-position control point is obtained using affine transformation. Based on the obtained control points, a Bezier Curve is constructed, and interpolation is performed on the curve to connect the cavity lines of the normal teeth on both sides.

[0081] Lingual cutting lines: Similarly, lingual cutting lines can also be divided into four types, and the method for generating cutting lines is the same as that for generating labial cutting lines.

[0082] Step S44: Detect whether the current tooth is a tail boundary tooth position. If it is a tail boundary tooth position, the 0th and 3rd quadrant tooth cavity lines of the current tooth cavity are directly stored as cutting line points in point set A as partial initial points for generating cutting lines.

[0083] Step S5: Smooth the entire cutting line, specifically including the following steps:

[0084] Step S51: Traverse the initial point of the cutting line, calculate the curvature of the circumcircle of the triangle constructed by each point and its two adjacent points, and the angle between the point and its two adjacent points. The angle range of the returned point is [0, 180°).

[0085] Step S52: Traverse the initial point of the cutting line. Determine whether smoothing is needed based on the circumcircle curvature and angle of each point obtained in step S51. If the difference between the circumcircle curvature of the traversed point and the points on the left and right sides is twice the difference between the curvature of the left point and its left adjacent point or twice the difference between the curvature of the right point and its adjacent point, and the current traversed point or the points before and after it are all cutting points of the erupting cap tooth position, then perform the smoothing operation. Alternatively, if the angle between the current point and the points on both sides is ≤165°, and the current point or the five points before and after it are marked as cutting points of the erupting cap tooth position, then perform the smoothing operation on the current traversed point and the two points before and after it. The smoothing mainly involves evenly distributing the five selected points on the straight line connecting the initial and end points.

[0086] Step S6: Filter duplicate points: Filter out duplicate points in the cutting line points after smoothing in step S5;

[0087] Step S7: Improve the curve: Further improve the cutting curve by moving the generated cutting line outward by a corresponding distance according to the input offset parameter (unit: mm) to obtain the moved point. Smooth the generated point to obtain a control line that can be applied to automatic cutting equipment.

[0088] Example 2

[0089] The electronic device in this embodiment includes:

[0090] At least one processor; and

[0091] At least one memory communicatively connected to the processor;

[0092] The memory stores instructions that can be executed by a processor, which are then executed by the processor to cause the electronic device to perform the method for automatically generating cutting lines for a braces model in Embodiment 1.

[0093] Example 3

[0094] In this embodiment, a computer-readable storage medium stores computer-executable instructions. When the processor executes the computer-executable instructions, it implements the method for automatically generating cutting lines of a braces model in Embodiment 1.

[0095] Many specific details have been set forth in the foregoing description to provide a thorough understanding of the present invention. However, the above description is merely a preferred embodiment of the present invention, and the present invention can be implemented in many other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed above. Furthermore, any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, using the methods and techniques disclosed above, without departing from the scope of the present invention. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A method for automatically generating cutting lines for a dental braces model, characterized in that: Based on the dental cavities line and eruption cap attachment, the specific steps include the following: Step S1: Obtain the virtual tooth hole line of the cute hat accessory; Step S2: Determine the eruption of the triangular teeth on the lingual side of the cap labium; Step S3: Merge the eruption cap attachment and its adjacent undercut grids into the entire dentition grid; Step S4: Traverse the tooth positions to construct labial and lingual incision lines; Step S5: Smooth the entire cutting line; Step S6: Filter duplicate points: Filter out duplicate points in the cutting line points after smoothing in step S5; Step S7: Improve the cutting line. Move the generated cutting line outward by a corresponding distance according to the input offset parameters to obtain the moved point. Smooth the generated point to obtain a control line that can be applied to automatic cutting equipment.

2. The method for automatically generating cutting lines for a braces model according to claim 1, characterized in that: Step S1 includes the following steps: Step S11: Traverse all tooth data by tooth position, mark whether the cavity of the current tooth position has an eruption cap attachment, and if there are multiple eruption caps for the current tooth position, merge the multiple eruption caps into one grid. Step S12: Obtain the initial eruption cap tooth cavity line, ensuring that the eruption cap tooth cavity line on the labial and lingual sides is 0.1 mm to 0.5 mm higher than the lowest point of the edge of the adjacent cavity lines on both sides; Step S13: Based on the initial cavity line of the eruption cap obtained in Step S12, determine the type of the eruption cap tooth: determine whether it is an external arch tooth by judging the spatial relationship between the cavity line of the eruption cap and the actual cavity line. If the current eruption cap is a non-external arch tooth, determine whether it is an eruption cap repaired decayed tooth by judging the wrapping of the cavity line of the eruption cap and the cavity line of the normal tooth. If the current tooth position is an eruption cap repaired decayed tooth, directly intersect the mesh after merging the eruption cap and the decayed tooth with the gingival mesh to obtain a new cavity line, and at the same time set the generation method of the current tooth position non-eruption cap, i.e., decayed tooth; if the current eruption cap is an external arch tooth, directly use the cavity line of the eruption cap. Step S14: Update the local coordinate system of the eruption cap: Based on the initial local coordinate system of the adjacent denture teeth, calculate the average value of each small coordinate of the teeth on both sides to obtain the average vector of the X, Y, and Z axes, which is used as the local coordinate system of the eruption cap. Step S15: Partitioning the eruption cap cavity line: Based on the updated X and Y directions of the eruption cap, obtain the starting points of the four quadrants of the eruption cap cavity. That is, project the points on the eruption cap cavity line onto the straight lines of the X and Y axes, find the maximum and minimum projection points in the two directions as the starting points of the quadrants, and divide the cavity line into four quadrants based on the starting points of the quadrants. The storage order of the points in different quadrants is different. The starting points of the quadrants in the X direction are the initial points of each quadrant, and the points in the Y direction are the end points of each quadrant. When dividing the points in each quadrant, it is necessary to store the points of each quadrant according to the clockwise and counterclockwise directions of the original cavity points. Among them, quadrants 0 and 1 are the two quadrants on the labial side, and quadrants 2 and 3 are the two quadrants on the lingual side. Step S16: The cavity points in quadrants 0 and 1 on the labial side and quadrants 2 and 3 on the lingual side are adjusted again along the z-axis based on the lowest point of the cavity line of the adjacent teeth on each side, so that the eruption cap cavity point in each quadrant is 0.1 mm to 0.5 mm higher than the lowest point on both sides. Step S17: Store all eruption cap accessories except for rotten teeth.

3. The method for automatically generating cutting lines for a braces model according to claim 2, characterized in that: In step S12, the method of obtaining the eruption cap cavity line is divided into boundary tooth eruption cap and non-boundary tooth eruption cap depending on the tooth position. For boundary tooth eruption cap, the cavity line of the eruption cap is intercepted by constructing a plane with the center point of the cavity line of the normal tooth at the current tooth position and the Z-axis direction of the jaw. For non-boundary tooth eruption cap, the small coordinates of the current eruption cap are determined according to the coordinate directions of the non-eruption cap teeth on both sides, and the cavity line is intercepted by constructing a plane with the local Z-axis and the center point of the cavity line of the moved eruption cap.

4. The method for automatically generating cutting lines for a braces model according to claim 1, characterized in that: In step S13, the method for determining an external eruption cap is as follows: if the distance between the center points of the two cavity lines is greater than 2.5 mm and the angle between the normals of the planes fitted by the two cavities is greater than 40°, then the current eruption cap is determined to be an external eruption cap tooth; the method for determining an eruption cap repaired decayed tooth is as follows: project both cavity lines onto the same plane, construct rays from the center point of the cavity line to each point on the actual cavity line, and project the points on the eruption cap cavity line onto each ray. If the distance from the projection point on the eruption cap cavity line to the center point of the actual cavity is less than the distance from the point on the actual cavity line to the center point, then the point on the actual cavity line is determined to be outside the projection point of the eruption cap cavity. If it is not outside, it is not recorded. If the number of points outside the eruption cap is greater than 1 / 8 of the number of points on the actual cavity, then it is proven that the current tooth position is an eruption cap repaired decayed tooth.

5. The method for automatically generating cutting lines for a braces model according to claim 1, characterized in that: The method for determining the labial and lingual triangular teeth that have erupted in step S2 is as follows: Lingual eruption of triangular teeth: Obtain the two points A and B closest to the lingual side on the 2nd and 3rd quadrants of the adjacent lingual cavities on the left and right sides. Compare these two points with the point C closest to the lingual side on the eruption cap lingual cavity line. Project points A, B, and C onto a ray constructed with point C and the Y-axis vector of the current tooth position. The starting point of this ray is point C, and the ray direction is the Y-axis direction. If the distance between the projection points of points A and B on the ray and point C is greater than 2 mm, and the two projection points are closer to the lingual side than point C, then the current tooth is determined to be a triangular tooth. The method for determining labial eruption of triangular cusps is the same as that for lingual eruption. It is also based on the degree of concavity of the dental cavity line in the Y-axis direction. That is, the points closest to the labial side on the current dental cavity line and the adjacent two dental cavity lines are projected onto a ray constructed along the Y-axis direction with the point closest to the labial side on the current dental cavity line as the starting point, and C1, A1, and B1 are obtained respectively. The distance between the three points is compared. If the distance between the projection points of points B1 and A1 on the ray and point C1 is greater than 2 mm and the two projection points are closer to the labial side than point C1, then the current tooth is determined to be a labial triangular cusps.

6. The method for automatically generating cutting lines for a braces model according to claim 1, characterized in that: Step S3 includes the following steps: Step S31: Obtain the inverted mesh adjacent to the budding cap; Step S32: Merge the eruption cap attachment obtained in step S1 and the undercut grid block obtained in step S31 onto the dental grid.

7. The method for automatically generating cutting lines for a braces model according to claim 1, characterized in that: Step S4 includes the following steps: Step S41: Detect whether the current tooth being traversed is a boundary tooth position. If it is a boundary tooth position, directly store the points in the 0th and 3rd quadrants of the current tooth position as cutting line points in point set A, as partial initial points for generating cutting lines. If it is not a boundary tooth position, execute steps S42-S44. Step S42: Based on the judgment result in step S2, determine whether the currently traversed tooth is a triangular tooth. If it is a labial triangular tooth, the jump connection is achieved from the lingual side: obtain the nearest point of the lingual grid of the gingiva below the current tooth position, find the two nearest points on the adjacent cavity quadrant as low control points, and finely adjust them 0.5 mm to 1.5 mm towards the center of the two control points; find the nearest point from the low control point to the cavity line, and record the corresponding cavity point indices IndexLeft and IndexRight as the jump connection position; based on the obtained low control points, take two cavity points along the labial direction of the cavity line as high control points, and finely adjust them 0.5 mm to 1.5 mm towards the center of the two control points; based on the four control points, use BezierCurve to construct the cavity connection curve, and connect the cavity lines on both sides of the triangular tooth at the jump index point. The projection direction of the connection curve is the average normal direction of the cavity construction plane on both sides. If it is a lingual triangular tooth, the jump connection is achieved from the labial side: based on the set jump distance between adjacent cavities, the low control point is obtained, and the high control point is obtained using affine transformation; the cavity connection curve is constructed using BezierCurve, and the cavity lines on both sides of the triangular tooth are connected at the jump index point. The projection direction of the connection curve is the average normal direction of the cavity construction plane on both sides. Step S43: Divide the cutting line into two parts, the labial and lingual sides, and generate them accordingly: Labial cutting line: Based on the different attributes of two adjacent cavities, there are four cases: ① The left normal tooth is currently erupting; ② The left erupting tooth is currently a normal tooth; ③ The left erupting tooth is currently an erupting tooth; ④ Both the left side and the current tooth position are normal teeth. For cases ① and ②, firstly, obtain the low-level control point based on the jump distance, and then obtain the high-level control point using affine transformation. Based on the obtained control points, construct a Bezier Curve, interpolate on the connecting curve, and project the interpolation points along the average normal direction of the three nearest mesh faces to obtain the projection points on the corresponding mesh; obtain the left and right lateral cutting lines. The cavity line and projection point are obtained, and 10 points extending before and after the cavity point are obtained as the original fitting points. Fourth-order polynomial fitting is performed. The fitted points are projected according to the average normal direction of the nearest face, and points falling inside the cavity and points of excessively curved curves are removed. For case ③, there is no need to construct connecting lines to directly connect the eruption cap cavities. For case ④, firstly, the low-level control point is obtained according to the jump distance, and the high-level control point is obtained using affine transformation. Based on the obtained control points, a Bezier Curve is constructed, and interpolation is performed on the connecting curve to connect the cavity lines of the normal teeth on both sides. Lingual cutting lines: Similarly, lingual cutting lines are also divided into four types, and the method for generating cutting lines is the same as that for generating labial cutting lines. Step S44: Detect whether the current tooth is a tail boundary tooth position. If it is a tail boundary tooth position, the 0th and 3rd quadrant tooth cavity lines of the current tooth cavity are directly stored as cutting line points in point set A as partial initial points for generating cutting lines.

8. The method for automatically generating cutting lines for a braces model according to claim 1, characterized in that: Step S5 includes the following steps: Step S51: Traverse the initial point of the cutting line, calculate the curvature of the circumcircle of the triangle constructed by each point and its two adjacent points, and the angle between the point and its two adjacent points; Step S52: Traverse the initial point of the cutting line. Determine whether smoothing is needed based on the circumcircle curvature and angle of each point obtained in step S51. If the difference between the circumcircle curvature of the traversed point and the points on the left and right sides is twice the difference between the curvature of the left point and its left adjacent point or twice the difference between the curvature of the right point and its adjacent point, and the current traversed point or the points before and after it are all cutting points of the erupting cap tooth position, then perform the smoothing operation. Alternatively, if the angle between the current point and the points on both sides is ≤165°, and the current point or the five points before and after it are marked as cutting points of the erupting cap tooth position, then perform the smoothing operation on the current traversed point and the two points before and after it. The smoothing mainly involves evenly distributing the five selected points on the straight line connecting the initial and end points.

9. An electronic device, characterized in that: include: At least one processor; as well as At least one memory communicatively connected to the processor; The memory stores instructions that can be executed by a processor, which, when executed by the processor, causes the electronic device to perform the method for automatically generating cutting lines for a braces model as described in any one of claims 1-8.

10. A computer-readable storage medium, characterized in that: It stores computer execution instructions, which, when executed by the processor, implement the method for automatically generating cutting lines of a braces model as described in any one of claims 1-8.

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