Method for filling undercuts of crowded dentition and its device and equipment

Abstract

The present invention provides a method for filling undercuts of crowded dentition, comprising obtaining a digital tooth model and several groups of dentition to be inspected, wherein each group of the dentition to be inspected includes three adjacent teeth; traversing the dentition to be inspected, performing crowding detection calculation on the dentition to be inspected, calculating the difference between the tooth distance and the bone distance of the second tooth and the angle between the center line of the second tooth and the first tooth and the third tooth; performing crowding detection according to the difference between the tooth distance and the bone distance of the second tooth and the angle between the center line, and obtaining a crowding detection result; after determining that the dentition to be inspected is crowded dentition, obtaining six groups of circle points in each group of crowded dentition; obtaining a three-dimensional convex hull according to the six groups of circle points, and performing surface subdivision on the three-dimensional convex hull to form a crowded undercut filling grid. The method overcomes the problem of increased resistance when taking a film caused by crowded dentition, and improves the processing efficiency and accuracy of filling undercuts of crowded dentition. The present invention also provides a device and equipment for implementing the method for filling undercuts of crowded dentition.

Description

Technical Field

[0001] The present invention relates to the technical field of tooth correction, and in particular to a method for filling undercuts of crowded dentition and a device and equipment thereof. Background Art

[0002] The undercut area generally refers to the triangular area formed by two teeth and the gum edge, which is usually concave relative to the teeth. If the undercut area is not filled, it will make it difficult to remove the shell-shaped dental appliance after the mold is completed. At the same time, it will cause the patient to press the gums and make it difficult to remove the shell-shaped dental appliance.

[0003] In the production process of shell-shaped dental orthodontic appliances, after the dental model is printed by 3D printing technology, before the film is pressed by hot pressing, the dental model needs to be filled with undercuts, and the undercut area between two adjacent teeth needs to be filled with solid fillings.

[0004] In the production process of existing shell-shaped dental appliances, undercuts of adjacent teeth are usually filled. However, if the patient has crowded dentition and the undercuts are not filled, the resistance will increase when the film is taken. In the prior art, the undercuts of two adjacent teeth have been filled using digital models, but the undercuts of crowded dentition are still filled manually using materials such as artificial stone, plaster or paraffin, such as the wax dripping method, which will result in low efficiency and poor accuracy in the filling of crowded dentition undercuts, increasing the scrap rate and rework rate.

[0005] Therefore, it is necessary to provide a method for filling undercuts in crowded dentition and a device and apparatus thereof to solve the above-mentioned problems in the prior art. Summary of the invention

[0006] The purpose of the present invention is to provide a method for filling undercuts in crowded dentition and a device and equipment thereof, so as to solve the problem of increased resistance when taking film due to crowded dentition and improve the processing efficiency and accuracy of filling undercuts in crowded dentition.

[0007] To achieve the above-mentioned purpose, the method for filling undercuts in crowded dentition of the present invention comprises:

[0008] Get digital models of teeth;

[0009] Grouping the teeth according to the digital tooth model to obtain a plurality of groups of dentitions to be inspected, wherein each group of three adjacent teeth forms a group of dentitions to be inspected;

[0010] Traversing the dentition to be inspected, and performing crowding detection calculation on the dentition to be inspected, the dentition to be inspected includes a first tooth, a second tooth, and a third tooth numbered in sequence, calculating the difference between the tooth distance and the bone distance of the second tooth and the angle between the second tooth and the center line connecting the first tooth and the third tooth;

[0011] Perform crowding detection according to the difference between the tooth distance and the bone distance of the second tooth and the angle between the center lines to obtain a crowding detection result;

[0012] After determining that the dentition to be inspected is a crowded dentition according to the crowding detection result, obtaining two groups of circle points of the concave surface boundary of each tooth between two adjacent teeth in the crowded dentition, and obtaining six groups of circle points in each group of the crowded dentition;

[0013] A three-dimensional convex hull is obtained according to the six groups of circle points, and the three-dimensional convex hull is tessellated to form a crowded, filled and inverted concave grid.

[0014] The beneficial effects of the method for filling undercuts of crowded dentition of the present invention are:

[0015] The method obtains a digital model of teeth, and groups the teeth according to the digital model of teeth to obtain several groups of teeth to be inspected, with each group of three adjacent teeth; traverses the teeth to be inspected to obtain the difference between the tooth distance and the bone distance of the second tooth and the angle between the center line of the second tooth and the first tooth and the third tooth, and performs crowding detection according to the difference between the tooth distance and the bone distance of the second tooth and the angle between the center line to obtain a crowding detection result, thereby providing a rigorous and reliable detection method for crowded teeth; obtains six groups of circle points in each group of crowded teeth, obtains a three-dimensional convex hull according to the six groups of circle points, and performs surface subdivision on the three-dimensional convex hull to form a crowded undercut grid; supplements the existing undercut filling algorithm with a method for filling undercuts in crowded teeth, overcomes the problem of increased resistance when taking the film caused by crowded teeth, makes demolding more convenient, and improves the processing efficiency and accuracy of filling undercuts in crowded teeth; performs surface subdivision on the three-dimensional convex hull, thereby making the surface of the obtained undercut edge area smoother.

[0016] Optionally, the step of calculating the difference between the tooth distance and the bone distance of the second tooth and the angle between the second tooth and the center line connecting the first tooth and the third tooth comprises:

[0017] Acquire a first tooth center of the first tooth, a second tooth center of the second tooth, and a third tooth center of the third tooth according to the first tooth, the second tooth, and the third tooth in the dentition to be examined;

[0018] Performing a straight line operation on the first tooth center and the third tooth center to obtain a first center line, projecting all points on the first tooth onto the first center line to obtain a first projection line segment, projecting all points on the third tooth onto the first center line to obtain a third projection line segment, and calculating the blank length between the first projection line segment and the third projection line segment to obtain the bone distance;

[0019] Projecting all points on the second tooth onto the first center line to obtain a second projection line segment, and calculating the length of the second projection line segment to obtain the tooth distance;

[0020] A division operation is performed on the tooth distance and the bone distance to obtain the difference between the tooth distance and the bone distance of the second tooth. Its beneficial effect is that by calculating the projection of the first tooth to obtain the first projection line segment, calculating the projection of the second tooth to obtain the second projection line segment, and calculating the projection of the third tooth to obtain the third projection line segment, the blank length between the first projection line segment and the third projection line segment is obtained to obtain the bone distance, the length of the second projection line segment is calculated to obtain the tooth distance, and the division operation is performed on the tooth distance and the bone distance to obtain the difference between the tooth distance and the bone distance of the second tooth; a reliable detection method is provided for the detection of the crowding of the dentition to be tested, and the detection efficiency and accuracy of the crowded dentition are high.

[0021] Optionally, the step of calculating the difference between the tooth distance and the bone distance of the second tooth and the angle between the second tooth and the center line connecting the first tooth and the third tooth further includes:

[0022] Performing a straight line operation on the first tooth center and the second tooth center to obtain a second center line, and performing a straight line operation on the second tooth center and the third tooth center to obtain a third center line;

[0023] The angle between the second center line and the third center line is calculated to obtain the center line angle. The beneficial effect is that the center line angle is obtained based on the center lines of the three teeth, and the calculation is fast and accurate, which further improves the detection efficiency and accuracy of crowded dentition.

[0024] Optionally, the crowding detection result includes crowded dentition and non-crowded dentition, and the crowding detection is performed according to the difference between the tooth distance and the bone distance of the second tooth and the angle between the center lines, and the step of obtaining the crowding detection result includes:

[0025] When the difference between the tooth distance and the bone distance of the second tooth is greater than the difference threshold and the center line angle is less than the angle threshold, determining that the dentition to be inspected is the crowded dentition;

[0026] When the difference between the tooth distance and the bone distance of the second tooth is less than the difference threshold or the center line angle is greater than the angle threshold, the dentition to be tested is determined to be the non-crowded dentition. Its beneficial effect is that when the difference between the tooth distance and the bone distance of the second tooth is greater than the difference threshold and the center line angle is less than the angle threshold, the dentition to be tested is determined to be the crowded dentition, which provides an effective judgment method for determining crowded dentition and facilitates the determination of all crowded dentitions in the dentition to be tested.

[0027] Optionally, the difference threshold is 1.3 to 1.6.

[0028] Optionally, the angle threshold is 105 degrees to 135 degrees.

[0029] Optionally, the step of obtaining two groups of circle points of the undercut boundary of each tooth between two adjacent teeth in the crowded dentition and obtaining six groups of circle points in each group of the crowded dentition comprises:

[0030] The teeth in each group of the crowded dentition are numbered in sequence to obtain a crowded first tooth, a crowded second tooth and a crowded third tooth, and a first median vertical plane between the crowded first tooth and the crowded second tooth, a second median vertical plane between the crowded second tooth and the crowded third tooth, and a third median vertical plane between the crowded first tooth and the crowded third tooth are obtained;

[0031] The second circle points on the crowded first tooth surface and the third circle points on the crowded second tooth surface are obtained according to the first median perpendicular plane, the fourth circle points on the crowded second tooth surface and the fifth circle points on the crowded third tooth surface are obtained according to the second median perpendicular plane, and the first circle points on the crowded first tooth surface and the sixth circle points on the crowded third tooth surface are obtained according to the third median perpendicular plane. The beneficial effect is that the present invention sequentially obtains the first circle points and the second circle points of the crowded first tooth, the third circle points and the fourth circle points of the crowded second tooth, and the fifth circle points and the sixth circle points of the crowded third tooth according to the first median perpendicular plane, the second median perpendicular plane, and the third median perpendicular plane, respectively, thereby further refining the range of crowded undercuts, improving the calculation accuracy of subsequent three-dimensional convex hulls and crowded undercuts, and improving the accuracy of crowded undercuts.

[0032] Optionally, the step of acquiring a three-dimensional convex hull according to the six groups of circle points includes:

[0033] The convex hull operation is performed on the first circle point, the second circle point, the third circle point, the fourth circle point, the fifth circle point and the sixth circle point to obtain the three-dimensional convex hull. The beneficial effect is that the present invention obtains two groups of circle points for each tooth in the crowded dentition, and after obtaining six groups of circle points for each group of crowded dentition, the convex hull operation is performed on the six groups of circle points to obtain the three-dimensional convex hull, and the three-dimensional convex hull surrounds all the circle points, thereby improving the processing efficiency of filling undercuts in crowded dentition and saving costs; the crowded undercut grid obtained by the three-dimensional convex hull fits the teeth better, so that the braces made according to the crowded undercut grid are more in line with the conditions of the crowded area, demoulding is easier, and the user is more comfortable wearing the braces.

[0034] The present invention also provides a device for filling undercuts of crowded dentition, comprising:

[0035] A digitization module, used for obtaining a digital model of teeth, and grouping teeth according to the digital model of teeth to obtain a plurality of groups of dentitions to be inspected, wherein each group of three adjacent teeth is the dentitions to be inspected;

[0036] a detection module, configured to traverse the dentition to be inspected and perform crowding detection calculation on the dentition to be inspected, wherein the dentition to be inspected includes a first tooth, a second tooth, and a third tooth numbered in sequence, calculate the difference between the tooth distance and the bone distance of the second tooth and the angle between the center line of the second tooth and the first tooth and the third tooth, and perform crowding detection according to the difference between the tooth distance and the bone distance of the second tooth and the angle between the center line to obtain a crowding detection result;

[0037] A circle point module, which obtains two groups of circle points of the concave surface boundary of each tooth between two adjacent teeth in the crowded dentition, and obtains six groups of circle points in each group of the crowded dentition;

[0038] The module for filling in the inverted concavities is used to obtain the three-dimensional convex hull according to the six groups of circle points, and to perform surface subdivision on the three-dimensional convex hull to form a crowded and inverted concavity-filled grid.

[0039] The beneficial effects of the undercut filling device for crowded dentition of the present invention are:

[0040] The device for filling undercuts of crowded dentition of the present invention first groups teeth to obtain dentition to be inspected, and detects the teeth in groups to improve the detection efficiency and accuracy of crowded dentition; then, the dentition to be inspected is traversed to obtain a crowding detection result, and the crowded dentition is obtained according to the crowding detection result, thereby providing a reliable and effective detection method for crowded dentition; then, six groups of circles are obtained by circling the crowded dentition to express the undercut surface boundary of the crowded dentition; finally, a three-dimensional convex hull is obtained according to the six groups of circles, and the three-dimensional convex hull is tessellated to form a crowded undercut filling grid, thereby improving the defect of imperfect undercut filling in the existing undercut filling algorithm, overcoming the film taking resistance problem caused by crowded dentition, making demolding more convenient, and improving the processing efficiency and accuracy of filling undercuts of crowded dentition.

[0041] The present invention also provides a device, comprising a memory and a processor, wherein the memory stores a program for filling undercuts for crowded dentition, and when the program for filling undercuts for crowded dentition is executed by the processor, the method for filling undercuts for crowded dentition is implemented.

[0042] The beneficial effects of the device of the present invention are:

[0043] The device is used to implement the method for filling undercuts in crowded dentition, provides a reliable detection method for crowded dentition, improves the defects of the imperfect undercut filling method in the existing undercut filling algorithm, overcomes the film removal resistance problem caused by crowded dentition, makes demolding more convenient, and improves the processing efficiency and accuracy of filling undercuts in crowded dentition. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A flow chart of a method for filling undercuts in crowded dentition according to an embodiment of the present invention;

[0045] Figure 2 A schematic diagram of a crowded and undercut grid according to an embodiment of the present invention;

[0046] Figure 3 A flow chart of calculating the difference between the tooth distance and the bone distance of the second tooth according to an embodiment of the present invention;

[0047] Figure 4 A flowchart of obtaining the center line angle according to an embodiment of the present invention;

[0048] Figure 5 A flowchart of obtaining six groups of circles in each group of crowded dentition according to an embodiment of the present invention;

[0049] Figure 6 It is a schematic structural diagram of the undercut filling device for crowded dentition of the present invention. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be understood by people with general skills in the field to which the present invention belongs. "Including" and similar words used in this article mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0051] In view of the problems existing in the prior art, the embodiment of the present invention provides a method for filling undercuts of the crowded dentition of the present invention, referring to Figure 1 ,include:

[0052] S0: Obtain digital tooth model;

[0053] The digital tooth model is a digital tooth-jaw model obtained by a scanner.

[0054] S1: grouping teeth according to the digital tooth model to obtain a plurality of groups of dentitions to be inspected, wherein each group of three adjacent teeth forms a group of dentitions to be inspected;

[0055] S2: traversing the dentition to be inspected and performing crowding detection calculation on the dentition to be inspected, wherein the dentition to be inspected includes a first tooth, a second tooth and a third tooth numbered in sequence, and calculating the difference between the tooth distance and the bone distance of the second tooth and the angle between the second tooth and the center line connecting the first tooth and the third tooth;

[0056] Among them, the first tooth, the second tooth and the third tooth numbered in sequence are the teeth to be inspected that are numbered in sequence according to the FDI tooth position representation method, and the three adjacent teeth numbered in sequence according to the FDI tooth position representation method are sequentially recorded as the first tooth, the second tooth and the third tooth.

[0057] In some embodiments, the step of sequentially numbering the dentition to be inspected according to the FDI tooth position representation method of the present invention is not limited to being performed after the step of acquiring several groups of dentition to be inspected and before the step of traversing the dentition to be inspected, but can also be performed after the step of acquiring the digital model of the teeth and before the step of grouping the teeth according to the digital model of the teeth to acquire several groups of dentition to be inspected; that is, after acquiring the digital model of the teeth, the digital model of the teeth is numbered according to the FDI tooth position representation method, and then the dentition to be inspected is grouped into three adjacent teeth corresponding to every three adjacent numbers, so as to facilitate the subsequent marking of the first tooth, the second tooth and the third tooth in the dentition to be inspected.

[0058] In this embodiment, by calculating the difference between the tooth distance and the bone distance of the second tooth and the angle between the center line of the second tooth and the first tooth and the third tooth, a reliable detection method is provided for detecting the crowding of the dentition to be tested, thereby improving the detection efficiency and accuracy of crowded dentition.

[0059] S3: performing crowding detection according to the difference between the tooth distance and the bone distance of the second tooth and the angle between the center lines to obtain a crowding detection result;

[0060] S4: after determining that the dentition to be inspected is a crowded dentition according to the crowding detection result, obtaining two groups of circle points of the concave surface boundary of each tooth between two adjacent teeth in the crowded dentition, and obtaining six groups of circle points in each group of the crowded dentition;

[0061] Among them, the six groups of circled points in each group of the crowded dentition are the boundaries of the undercut surface of the crowded dentition. The area where the crowded dentition is filled with undercuts is determined by the six groups of circled points, which improves the calculation accuracy of the subsequent three-dimensional convex hull and crowded undercut-filled mesh, and improves the accuracy of the crowded undercut-filled mesh.

[0062] S5: Obtain a three-dimensional convex hull according to the six groups of circle points, and perform surface subdivision on the three-dimensional convex hull to form a crowded, filled, and inverted concave grid.

[0063] In order to obtain a crowded undercut grid in the present application, the teeth are first grouped according to the digital tooth model to obtain a plurality of groups of dentitions to be tested, with each group of three adjacent teeth forming one group of dentitions to be tested; the difference between the tooth distance and the bone distance of the second tooth and the angle between the center line of the second tooth, the first tooth and the third tooth are obtained by traversing the dentition to be tested, and crowding detection is performed based on the difference between the tooth distance and the bone distance of the second tooth and the angle between the center line to obtain a crowding detection result, thereby providing a rigorous and reliable detection method for crowded dentition; in each group of Six groups of circle points are obtained from the crowded dentition, a three-dimensional convex hull is obtained according to the six groups of circle points, and the three-dimensional convex hull is tessellated to form a crowded undercut grid; the defect of imperfect undercut filling in the existing undercut filling algorithm is improved, the film taking resistance problem caused by crowded dentition is overcome, demoulding is more convenient, and the processing efficiency and accuracy of filling undercuts in crowded dentition are improved; by performing a tessellation operation on the three-dimensional convex hull, the surface of the obtained undercut edge area is made smoother and more delicate, thereby improving the calculation accuracy of the crowded undercut filling grid and the accuracy of the undercut filling operation.

[0064] In some embodiments, after step S5, the finally formed crowded filling undercut grid is as follows: Figure 2 shown.

[0065] As an optional implementation of the present invention, in step S2, referring to Figure 3 The step of calculating the difference between the tooth distance and the bone distance of the second tooth and the angle between the second tooth and the center line connecting the first tooth and the third tooth comprises:

[0066] S201: acquiring a first tooth center of the first tooth, a second tooth center of the second tooth, and a third tooth center of the third tooth according to the first tooth, the second tooth, and the third tooth in the dentition to be inspected;

[0067] S202: performing a straight line operation on the first tooth center and the third tooth center to obtain a first center line, and projecting all points on the first tooth onto the first center line to obtain a first projection line segment;

[0068] S203: Projecting all points on the third tooth onto the first center line to obtain a third projection line segment, and calculating the blank length between the first projection line segment and the third projection line segment to obtain the bone distance;

[0069] S204: Projecting all points on the second tooth onto the first center line to obtain a second projection line segment, and calculating the length of the second projection line segment to obtain the tooth distance;

[0070] It should be noted that, in the above steps S202 to S204, all points on the first tooth, the second tooth and the third tooth are projected onto the first center line respectively, and the projection directions of all points of the first tooth, the second tooth and the third tooth onto the first center line are the same to ensure the accuracy of the crowded dentition detection calculation.

[0071] S205: Perform a division operation on the tooth distance and the bone distance to obtain a difference between the tooth distance and the bone distance of the second tooth.

[0072] As an optional implementation of the present invention, in step S2, after performing step S201, refer to Figure 4 The step of calculating the difference between the tooth distance and the bone distance of the second tooth and the angle between the second tooth and the center line connecting the first tooth and the third tooth also includes:

[0073] S211: performing a straight line operation on the first tooth center and the second tooth center to obtain a second center line, and performing a straight line operation on the second tooth center and the third tooth center to obtain a third center line;

[0074] S212: Calculate the angle between the second center line and the third center line to obtain the center line angle.

[0075] As an optional embodiment of the present invention, in step S3, the crowding detection result includes crowded dentition and non-crowded dentition, and the crowding detection is performed according to the difference between the tooth distance and the bone distance of the second tooth and the angle between the center lines, and the step of obtaining the crowding detection result includes:

[0076] When the difference between the tooth distance and the bone distance of the second tooth is greater than the difference threshold and the center line angle is less than the angle threshold, determining that the dentition to be inspected is the crowded dentition;

[0077] When the difference between the tooth distance and the bone distance of the second tooth is less than the difference threshold or the center line angle is greater than the angle threshold, the dentition to be inspected is determined to be the non-crowded dentition.

[0078] In some embodiments, the tooth distance of the to-be-tested dentition is recorded as A, the bone distance is recorded as B, the angle between the center lines of the first tooth and the third tooth is recorded as θ, and the difference threshold is recorded as D. threshold , the angle threshold is denoted as θ threshold ; Then the difference between the tooth distance and bone distance of the second tooth is

[0079] when And θ<θ threshold When the dentition to be inspected is determined to be a crowded dentition;

[0080] when Or θ>θ threshold When the dentition to be inspected is determined to be a non-crowded dentition.

[0081] In some optional embodiments, the difference threshold is 1.3 to 1.6.

[0082] In some optional embodiments, the angle threshold is 105 degrees to 135 degrees.

[0083] As an optional implementation of the present invention, in step S4, referring to Figure 5 The step of obtaining two groups of circle points of the concave surface boundary of each tooth between two adjacent teeth in the crowded dentition and obtaining six groups of circle points in each group of the crowded dentition includes:

[0084] S401: numbering the teeth in each group of the crowded dentition in sequence to obtain a crowded first tooth, a crowded second tooth and a crowded third tooth;

[0085] Among them, when it is confirmed that the dentition to be examined is a crowded dentition, the crowded first tooth of the crowded dentition corresponds to the first tooth of the dentition to be examined, the crowded second tooth of the crowded dentition corresponds to the second tooth of the dentition to be examined, and the crowded third tooth of the crowded dentition corresponds to the third tooth of the dentition to be examined.

[0086] S402: Acquire a first median vertical plane between the crowded first tooth and the crowded second tooth, a second median vertical plane between the crowded second tooth and the crowded third tooth, and a third median vertical plane between the crowded first tooth and the crowded third tooth;

[0087] The steps of obtaining the first mid-vertical plane, the second mid-vertical plane and the third mid-vertical plane include:

[0088] Draw a straight line segment with the center of the first crowded tooth and the center of the second crowded tooth as endpoints to obtain a first line segment, and draw a perpendicular plane through the center of the first line segment to obtain the first perpendicular plane;

[0089] Draw a straight line segment with the center of the second crowded tooth and the center of the third crowded tooth as endpoints to obtain a second line segment, and draw a perpendicular plane through the center of the second line segment to obtain the second perpendicular plane;

[0090] A straight line segment is drawn with the center of the first crowded tooth and the center of the third crowded tooth as endpoints to obtain a third line segment, and a perpendicular plane is drawn through the center of the third line segment to obtain the third perpendicular plane.

[0091] S403: Acquire a second circle point on the crowded first tooth surface and a third circle point on the crowded second tooth surface according to the first median perpendicular plane;

[0092] S404: Acquire a fourth circle point on the surface of the crowded second tooth and a fifth circle point on the surface of the crowded third tooth according to the second median perpendicular plane;

[0093] S405: Acquire a first circle point on the crowded first tooth surface and a sixth circle point on the crowded third tooth surface according to the third median perpendicular plane.

[0094] In some embodiments, the first circle of dots, the second circle of dots, the third circle of dots, the fourth circle of dots, the fifth circle of dots, and the sixth circle of dots each include 30 dots.

[0095] In some optional embodiments, the specific steps of obtaining the first circle point, the second circle point, the third circle point, the fourth circle point, the fifth circle point and the sixth circle point in step S22 include:

[0096] (1) obtaining a first intermediate circle on the first perpendicular plane with the midpoint of the first line segment as the center and 3 mm as the radius, and uniformly sampling 30 points on the first intermediate circle as first sampling circle points;

[0097] Project the first sampling circle points to the crowded first tooth to obtain the point on the surface of the crowded first tooth that is closest to each point in the first sampling circle points, so as to calculate the second circle points, and the number of sampling points of the second circle points is 30; Project the first sampling circle points to the crowded second tooth to obtain the point on the surface of the crowded second tooth that is closest to each point in the sampling circle points, so as to calculate the third circle points, and the number of sampling points of the third circle points is 30;

[0098] (2) obtaining a second middle circle on the second perpendicular plane with the midpoint of the second line segment as the center and 3 mm as the radius, and uniformly sampling 30 points on the second middle circle as second sampling circle points;

[0099] Project the second sampling circle points onto the crowded second tooth to obtain the point on the surface of the crowded second tooth closest to each point in the second sampling circle points, so as to calculate the fourth circle points, and the number of sampling points of the fourth circle points is 30; Project the second sampling circle points onto the crowded third tooth to obtain the point on the surface of the crowded third tooth closest to each point in the second sampling circle points, so as to calculate the fifth circle points, and the number of sampling points of the fifth circle points is 30;

[0100] (3) obtaining a third middle circle on the first perpendicular median plane with the midpoint of the third line segment as the center and 3 mm as the radius, and uniformly sampling 30 points on the third middle circle as third sampling circle points;

[0101] The third sampling circle points are projected onto the crowded first tooth to obtain the point on the surface of the crowded first tooth that is closest to each point in the third sampling circle points, so as to calculate the first circle points, and the number of sampling points of the first circle points is 30; the third sampling circle points are projected onto the crowded third tooth to obtain the point on the surface of the crowded third tooth that is closest to each point in the third sampling circle points, so as to calculate the sixth circle points, and the number of sampling points of the sixth circle points is 30.

[0102] As an optional implementation manner of the present invention, in step S5, the step of obtaining the three-dimensional convex hull according to the six groups of circle points includes:

[0103] A convex hull operation is performed on the first circle points, the second circle points, the third circle points, the fourth circle points, the fifth circle points, and the sixth circle points to obtain the three-dimensional convex hull.

[0104] It should be noted that the digital undercut in the prior art is the undercut between two adjacent teeth, and a circle operation is required for every two teeth to obtain the undercut area; the present invention obtains two circles of points for each tooth in the crowded dentition through the circle operation, and after obtaining six circles of points for each group of crowded dentition, a convex hull operation is performed on the six circles of points to obtain the three-dimensional convex hull, which surrounds all the circles, thereby improving the processing efficiency of the crowded dentition undercut grid and saving costs; the crowded undercut grid obtained by the three-dimensional convex hull fits the teeth better, so that the braces subsequently made according to the crowded undercut grid are more in line with the conditions of the crowded area, demoulding is easier, and the users are more comfortable wearing the braces.

[0105] Specifically, the algorithm for obtaining the three-dimensional convex hull for the six groups of circle points may adopt any one of a fast convex hull algorithm, a Graham scanning method, and a divide-and-conquer algorithm. The above algorithms are all existing technologies and will not be described in detail here.

[0106] In some optional embodiments, in step S5, the present invention is not limited to obtaining a crowded and inverted concave mesh by performing a surface subdivision operation on the three-dimensional convex hull, but can also optimize the vertices on the three-dimensional convex hull through a Laplace smoothing algorithm, thereby making the surface of the three-dimensional convex hull smoother, thereby optimizing the subsequent crowded and inverted concave mesh and improving the calculation accuracy of the crowded and inverted concave mesh.

[0107] In some embodiments, in step S5, the three-dimensional convex hull is tessellated to form a crowded and inverted concave grid, wherein the tessellation may be performed using a Loop tessellation method or a Catmull-Clark tessellation method, which are both prior arts and will not be described in detail herein.

[0108] In some embodiments, in step S5, after the three-dimensional convex hull is subjected to a tessellation operation, the crowded undercut mesh obtained is for the undercuts of the crowded dentition, while the undercuts of the non-crowded dentition can be calculated using the existing digital undercut technology; finally, a collection of the undercut mesh of the crowded dentition and the undercut mesh of the non-crowded dentition is calculated to obtain the undercut mesh of the entire dentition; the undercut mesh of the entire dentition is used to fill the undercuts, thereby improving the efficiency of filling the undercuts.

[0109] Figure 6 It is a schematic structural diagram of the undercut filling device for crowded dentition of the present invention.

[0110] The present invention also provides a device for filling undercuts in crowded dentition, referring to Figure 6 ,include:

[0111] A digitization module 1 is used to obtain a digital model of teeth, and group the teeth according to the digital model to obtain a plurality of groups of dentitions to be inspected, wherein each group of three adjacent teeth is a group of dentitions to be inspected;

[0112] Detection module 2, used for traversing the dentition to be inspected and performing crowding detection calculation on the dentition to be inspected, the dentition to be inspected includes a first tooth, a second tooth and a third tooth numbered in sequence, calculating the difference between the tooth distance and the bone distance of the second tooth and the angle between the center line of the second tooth and the first tooth and the third tooth, and performing crowding detection according to the difference between the tooth distance and the bone distance of the second tooth and the angle between the center line to obtain a crowding detection result;

[0113] The circle module 3 obtains two groups of circle points of the concave surface boundary of each tooth between two adjacent teeth in the crowded dentition, and obtains six groups of circle points in each group of the crowded dentition;

[0114] The undercut filling module 4 is used to obtain a three-dimensional convex hull according to the six groups of circle points, and perform surface subdivision on the three-dimensional convex hull to form a crowded undercut filling grid.

[0115] The advantages of the undercut filling device for crowded dentition of the present invention are:

[0116] The device for filling undercuts of crowded dentition of the present invention first groups teeth to obtain dentition to be inspected, and detects the teeth in groups to improve the detection efficiency and accuracy of crowded dentition; then, the dentition to be inspected is traversed to obtain crowding detection results, and crowded dentition is obtained according to the crowding detection results; a reliable and effective detection method for crowded dentition is provided; then, six groups of circles are obtained by circling the crowded dentition to express the undercut surface boundaries of the crowded dentition; finally, a three-dimensional convex hull is obtained according to the six groups of circles, and the three-dimensional convex hull is tessellated to form a crowded undercut filling grid, which improves the defect of imperfect undercut filling in the existing undercut filling algorithm, overcomes the film taking resistance problem caused by crowded dentition, makes demolding more convenient, and improves the processing efficiency and accuracy of filling undercuts of crowded dentition.

[0117] In some optional specific embodiments, refer to Figure 6 The working steps of the crowded dentition filling undercut device of the present invention include:

[0118] (1) obtaining a digital model of teeth through a digitalization module 1, and grouping the teeth according to the digital model of teeth to obtain a plurality of groups of dentitions to be inspected, wherein each group of dentitions to be inspected consists of three adjacent teeth;

[0119] (2) traversing the dentition to be inspected by the detection module 2, and performing crowding detection calculation on the dentition to be inspected, wherein the dentition to be inspected includes a first tooth, a second tooth, and a third tooth numbered in sequence, and calculating the difference between the tooth distance and the bone distance of the second tooth and the angle between the second tooth and the center line connecting the first tooth and the third tooth. The specific steps include:

[0120] Acquire a first tooth center of the first tooth, a second tooth center of the second tooth, and a third tooth center of the third tooth according to the first tooth, the second tooth, and the third tooth in the dentition to be examined;

[0121] Perform a straight line operation on the first tooth center and the third tooth center to obtain a first center line, project all points on the first tooth onto the first center line to obtain a first projection line segment, project all points on the third tooth onto the first center line to obtain a third projection line segment, calculate the blank length between the first projection line segment and the third projection line segment to obtain the bone distance; project all points on the second tooth onto the first center line to obtain a second projection line segment, calculate the length of the second projection line segment to obtain the tooth distance; perform a division operation on the tooth distance and the bone distance to obtain the difference between the tooth distance and the bone distance of the second tooth;

[0122] Performing a straight line operation on the first tooth center and the second tooth center to obtain a second center line, and performing a straight line operation on the second tooth center and the third tooth center to obtain a third center line; calculating an angle between the second center line and the third center line to obtain the center line angle;

[0123] (3) The detection module 2 performs crowding detection according to the difference between the tooth distance and the bone distance of the second tooth and the angle between the center lines to obtain a crowding detection result, and the specific steps include:

[0124] When the difference between the tooth distance and the bone distance of the second tooth is greater than the difference threshold and the center line angle is less than the angle threshold, determining that the dentition to be inspected is the crowded dentition;

[0125] When the difference between the tooth distance and the bone distance of the second tooth is less than the difference threshold or the center line angle is greater than the angle threshold, determining that the dentition to be inspected is the non-crowded dentition;

[0126] (4) two groups of circle points of the concave surface boundary of each tooth between two adjacent teeth in the crowded dentition are obtained by the circle point module 3, and six groups of circle points are obtained in each group of the crowded dentition. The specific steps include:

[0127] The teeth in each group of the crowded dentition are numbered in sequence to obtain a crowded first tooth, a crowded second tooth and a crowded third tooth, and a first median vertical plane between the crowded first tooth and the crowded second tooth, a second median vertical plane between the crowded second tooth and the crowded third tooth, and a third median vertical plane between the crowded first tooth and the crowded third tooth are obtained;

[0128] Acquire the second circle points on the crowded first tooth surface and the third circle points on the crowded second tooth surface according to the first median perpendicular plane, acquire the fourth circle points on the crowded second tooth surface and the fifth circle points on the crowded third tooth surface according to the second median perpendicular plane, and acquire the first circle points on the crowded first tooth surface and the sixth circle points on the crowded third tooth surface according to the third median perpendicular plane;

[0129] (5) Obtaining a three-dimensional convex hull according to the six groups of circle points by the inverted concave filling module 4, and performing surface subdivision on the three-dimensional convex hull to form a crowded inverted concave filling grid, wherein the step of obtaining a three-dimensional convex hull according to the six groups of circle points includes:

[0130] A convex hull operation is performed on the first circle points, the second circle points, the third circle points, the fourth circle points, the fifth circle points, and the sixth circle points to obtain the three-dimensional convex hull.

[0131] The present invention also provides a device, comprising a memory and a processor, wherein the memory stores a program for filling undercuts for crowded dentition, and when the program for filling undercuts for crowded dentition is executed by the processor, the method for filling undercuts for crowded dentition is implemented.

[0132] The advantages of the device of the present invention are:

[0133] The device is used to implement the method for filling undercuts in crowded dentition, provides a reliable detection method for crowded dentition, improves the defect of imperfect undercut filling in existing undercut filling algorithms, overcomes the film removal resistance problem caused by crowded dentition, makes demolding more convenient, and improves the processing efficiency and accuracy of filling undercuts in crowded dentition.

[0134] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.

Claims

1. A method for filling undercuts in crowded dentition, characterized in that: include: Get digital models of teeth; Grouping the teeth according to the digital tooth model to obtain a plurality of groups of dentitions to be inspected, wherein each group of three adjacent teeth forms a group of dentitions to be inspected; Traversing the dentition to be inspected, and performing crowding detection calculation on the dentition to be inspected, the dentition to be inspected includes a first tooth, a second tooth, and a third tooth numbered in sequence, calculating the difference between the tooth distance and the bone distance of the second tooth and the angle between the second tooth and the center line connecting the first tooth and the third tooth; Perform crowding detection according to the difference between the tooth distance and the bone distance of the second tooth and the angle between the center lines to obtain a crowding detection result; After determining that the dentition to be inspected is a crowded dentition according to the crowding detection result, obtaining two groups of circle points of the concave surface boundary of each tooth between two adjacent teeth in the crowded dentition, and obtaining six groups of circle points in each group of the crowded dentition; Obtain a three-dimensional convex hull according to the six groups of circle points, and perform surface subdivision on the three-dimensional convex hull to form a crowded, filled, and inverted concave grid; The step of calculating the difference between the tooth distance and the bone distance of the second tooth and the angle between the second tooth and the center line connecting the first tooth and the third tooth comprises: Acquire a first tooth center of the first tooth, a second tooth center of the second tooth, and a third tooth center of the third tooth according to the first tooth, the second tooth, and the third tooth in the dentition to be examined; Performing a straight line operation on the first tooth center and the third tooth center to obtain a first center line, projecting all points on the first tooth onto the first center line to obtain a first projection line segment, projecting all points on the third tooth onto the first center line to obtain a third projection line segment, and calculating the blank length between the first projection line segment and the third projection line segment to obtain the bone distance; Projecting all points on the second tooth onto the first center line to obtain a second projection line segment, and calculating the length of the second projection line segment to obtain the tooth distance; A division operation is performed on the tooth distance and the bone distance to obtain a difference between the tooth distance and the bone distance of the second tooth.

2. The method for filling undercuts in crowded dentition according to claim 1, characterized in that: The step of calculating the difference between the tooth distance and the bone distance of the second tooth and the angle between the second tooth and the center line connecting the first tooth and the third tooth also includes: Performing a straight line operation on the first tooth center and the second tooth center to obtain a second center line, and performing a straight line operation on the second tooth center and the third tooth center to obtain a third center line; The angle between the second center line and the third center line is calculated to obtain the center line angle.

3. The method for filling undercuts in crowded dentition according to claim 2, characterized in that: The crowding detection result includes crowded dentition and non-crowded dentition, and the crowding detection is performed according to the difference between the tooth distance and the bone distance of the second tooth and the angle between the center lines, and the step of obtaining the crowding detection result includes: When the difference between the tooth distance and the bone distance of the second tooth is greater than a difference threshold and the center line angle is less than an angle threshold, determining that the dentition to be inspected is the crowded dentition; When the difference between the tooth distance and the bone distance of the second tooth is less than the difference threshold or the center line angle is greater than the angle threshold, the dentition to be inspected is determined to be the non-crowded dentition.

4. The method for filling undercuts in crowded dentition according to claim 3, characterized in that: The difference threshold is 1.3 to 1.

6.

5. The method for filling undercuts in crowded dentition according to claim 3, characterized in that: The angle threshold is 105 degrees to 135 degrees.

6. The method for filling undercuts in crowded dentition according to claim 1, characterized in that: The step of obtaining two groups of circle points of the concave surface boundary of each tooth between two adjacent teeth in the crowded dentition and obtaining six groups of circle points in each group of the crowded dentition comprises: The teeth in each group of the crowded dentition are numbered in sequence to obtain a crowded first tooth, a crowded second tooth and a crowded third tooth, and a first median vertical plane between the crowded first tooth and the crowded second tooth, a second median vertical plane between the crowded second tooth and the crowded third tooth, and a third median vertical plane between the crowded first tooth and the crowded third tooth are obtained; The second circle points on the crowded first tooth surface and the third circle points on the crowded second tooth surface are obtained according to the first median perpendicular plane, the fourth circle points on the crowded second tooth surface and the fifth circle points on the crowded third tooth surface are obtained according to the second median perpendicular plane, and the first circle points on the crowded first tooth surface and the sixth circle points on the crowded third tooth surface are obtained according to the third median perpendicular plane.

7. The method for filling undercuts in crowded dentition according to claim 6, characterized in that: The step of obtaining the three-dimensional convex hull according to the six groups of circle points comprises: A convex hull operation is performed on the first circle points, the second circle points, the third circle points, the fourth circle points, the fifth circle points, and the sixth circle points to obtain the three-dimensional convex hull.

8. A device for filling undercuts in crowded dentition, characterized in that: include: A digitization module, used for obtaining a digital model of teeth, and grouping teeth according to the digital model of teeth to obtain a plurality of groups of dentitions to be inspected, wherein each group of three adjacent teeth is the dentitions to be inspected; a detection module, configured to traverse the dentition to be inspected and perform crowding detection calculation on the dentition to be inspected, wherein the dentition to be inspected includes a first tooth, a second tooth, and a third tooth numbered in sequence, calculate the difference between the tooth distance and the bone distance of the second tooth and the angle between the center line of the second tooth and the first tooth and the third tooth, and perform crowding detection according to the difference between the tooth distance and the bone distance of the second tooth and the angle between the center line to obtain a crowding detection result; A circle point module, which obtains two groups of circle points of the concave surface boundary of each tooth between two adjacent teeth in the crowded dentition, and obtains six groups of circle points in each group of the crowded dentition; A concave-filling module is used to obtain a three-dimensional convex hull according to the six groups of circle points, and perform surface subdivision on the three-dimensional convex hull to form a crowded concave-filling grid; The step of calculating the difference between the tooth distance and the bone distance of the second tooth and the angle between the second tooth and the center line connecting the first tooth and the third tooth comprises: Acquire a first tooth center of the first tooth, a second tooth center of the second tooth, and a third tooth center of the third tooth according to the first tooth, the second tooth, and the third tooth in the dentition to be examined; Performing a straight line operation on the first tooth center and the third tooth center to obtain a first center line, projecting all points on the first tooth onto the first center line to obtain a first projection line segment, projecting all points on the third tooth onto the first center line to obtain a third projection line segment, and calculating the blank length between the first projection line segment and the third projection line segment to obtain the bone distance; Projecting all points on the second tooth onto the first center line to obtain a second projection line segment, and calculating the length of the second projection line segment to obtain the tooth distance; A division operation is performed on the tooth distance and the bone distance to obtain a difference between the tooth distance and the bone distance of the second tooth.

9. A device, characterized in that: It comprises a memory and a processor, wherein the memory stores a program for filling undercuts of crowded dentition, and when the program for filling undercuts of crowded dentition is executed by the processor, the method for filling undercuts of crowded dentition as described in any one of claims 1 to 7 is implemented.

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