CN117503392A

CN117503392A - Method for setting a dental rotary accessory and for manufacturing a dental appliance, and associated device

Info

Publication number: CN117503392A
Application number: CN202210910404.9A
Authority: CN
Inventors: 黄恺; 马剑威; 姚峻峰
Original assignee: Shanghai Zhengya Dental Technology Co Ltd
Current assignee: Shanghai Zhengya Dental Technology Co Ltd
Priority date: 2022-07-29
Filing date: 2022-07-29
Publication date: 2024-02-06

Abstract

The embodiment of the invention relates to the technical field of tooth correction, and discloses a method for setting a tooth rotation accessory, a method for manufacturing a tooth correction device and a related device. The setting method comprises the following steps: acquiring a first digital model of the target tooth; after the correction force is applied to the rotating attachment, the maximum ratio of moment components of the correction force twisting around the long axis of the tooth according to the target direction is used as a target, and a target force application point and a target force application direction are determined on the adding side of the rotating attachment of the first digital model, wherein the target direction is clockwise or anticlockwise, and the correction force is the force applied to the rotating attachment by the shell-shaped appliance when the shell-shaped appliance is meshed with the rotating attachment arranged on the target tooth; and determining a target pose of the rotary accessory on the rotary accessory adding side of the first digital model according to the target force application point and the target force application direction so as to set the rotary accessory on the rotary accessory adding side of the first digital model based on the target pose. The automatic setting of the rotary accessory is completely realized.

Description

Method for setting a dental rotary accessory and for manufacturing a dental appliance, and associated device

Technical Field

The embodiment of the invention relates to the technical field of tooth correction, in particular to a method for setting a tooth rotation accessory, a method for manufacturing a tooth correction device and a related device.

Background

The removable invisible tooth appliance is a transparent elastic appliance designed and manufactured by computer assistance, achieves the purpose of tooth correction by continuously moving teeth in a small range, and is more and more favored by patients and doctors due to the characteristics of attractive appearance, accuracy and the like. The movement of the teeth is usually realized by assembling a shell-shaped appliance with the expected movement position information of the teeth and the teeth, and accessories are adhered to the surfaces of the teeth to play the roles of transmitting the correction force and fixing the shell-shaped appliance, so that the correction effect of torsion or translation of the teeth is finally achieved.

Tooth torsion is an important aspect in tooth correction, and the most difficult to achieve is that the influence factor of tooth torsion is more, and the motion analysis after stress is more complex. At present, in order to realize tooth torsion in the process of tooth correction, various methods for designing and/or placing accessories have been proposed, such as patent CN113288470a, pressure accessory designing method, appliance forming method, system and storage medium, and patent CN105496573a, method for providing accessories for tooth correction, the accessories, etc. However, the current attachment setting method for achieving the tooth torsion cannot completely separate from the manual work due to the fact that the parameter setting is required to be performed empirically.

Disclosure of Invention

The embodiment of the invention aims to provide a method for setting a tooth rotary accessory, a method for manufacturing a tooth appliance and a related device, so that manual participation can be avoided in the process of setting the rotary accessory, and automatic setting of the accessory is completely realized.

To achieve the above object, an embodiment of the present invention provides a method for setting a tooth rotating attachment, including: acquiring a first digital model of a target tooth, wherein the target tooth is a tooth to be corrected by adding a rotary accessory; after the correction force is applied to the rotary accessory, the correction force is the largest in torque component ratio of twisting around the long axis of the tooth according to the target direction, and a target force application point and a target force application direction are determined on the rotary accessory adding side of the first digital model, wherein the target direction is clockwise or anticlockwise, and the correction force is the force applied to the rotary accessory by the shell-shaped appliance when the shell-shaped appliance is meshed with the rotary accessory arranged on the target tooth; and determining a target pose of the rotary accessory on the rotary accessory adding side of the first digital model according to the target force application point and the target force application direction so as to set the rotary accessory on the rotary accessory adding side of the first digital model based on the target pose.

According to the setting method of the tooth rotating accessory, after the first digital model of the target tooth which needs to be twisted in the correcting process is obtained, the torque component ratio of the correcting force which is twisted around the long axis of the tooth according to the target direction is the largest after the correcting force is applied to the rotating accessory, the target force application point and the target force application direction are determined on the rotating accessory adding side of the first digital model, and then the target pose of the rotating accessory on the rotating accessory adding side of the first digital model is determined according to the target force application point and the target force application direction, so that the rotating accessory is set on the rotating accessory adding side of the first digital model based on the target pose, the torque component ratio of the target tooth which is twisted around the long axis of the tooth according to the target direction is the largest under the effect of the rotating accessory, the torsion around the long axis of the tooth can be realized to the largest, the target tooth is easier to be rotated to the expected position, and the efficiency is higher. The method mainly comprises the steps of summarizing the position design of the selected accessory into a stress analysis problem, determining the force application position and direction of the force through the position with the largest contribution of the force to tooth rotation, and determining the pose of the accessory, so that the setting of relevant parameters based on experience is reduced as much as possible in the process of determining the target force application point and the target force application direction, the manual participation is avoided, and the automatic setting of the accessory is completely realized.

Further, the determining, on the rotating attachment addition side of the first digital model, the target point of application and the target direction of application with the maximum ratio of moment components of the orthodontic force twisting around the tooth long axis in the target direction after the orthodontic force is applied to the rotating attachment includes: determining a local coordinate system of the first digitized model; generating a target model under a local coordinate system of the first digital model, wherein the target model takes a force application point and a force application direction as variables, takes the addition side of the rotating accessory with the force application point positioned on the first digital model as a constraint condition, and takes the maximum ratio of a moment component of the correction force, which is twisted around the long axis of the tooth according to the target direction, to the total moment as a target function; and determining an optimal solution of the target model to obtain the target force application point and the target force application direction. The target model is constructed based on the stress condition of the teeth and the set target of the rotary accessory, so that the target force application point and the target force application direction can be accurately and efficiently determined according to various optimal solution algorithms.

Further, the determining the local coordinate system of the first digitized model includes: determining the tooth long axis direction, the near-far middle direction and the labial-lingual direction of the first digital model; determining an impedance center of the first digitized model; and generating a local coordinate system of the first digital model by taking the determined tooth long axis direction, the determined near-far middle direction and the determined labial lingual direction as three axes of the coordinate system and taking the impedance center as an origin of the coordinate system. The tooth long axis is taken as one coordinate axis of a coordinate system relied when the target model is constructed, so that moment components which are twisted around the tooth long axis can be determined directly based on coordinate representation of the force application points and the force application directions, moment components which are twisted around the tooth long axis are prevented from being decomposed from the total moment, the construction and the solution of the target model are simplified, the realization difficulty is reduced, and the processing efficiency is improved.

Further, in the case that the target direction is a counterclockwise direction, the target model is:

in the case that the target direction is clockwise, the target model is:

wherein F (x, y, z) =0 is a curved surface expression of the rotating accessory addition side of the digitized model in a local coordinate system of the digitized model, (a, b, c) x (x, y, z) represents a cross operation of vector (a, b, c) and vector (x, y, z).

Further, the determining the tooth long axis direction, the mesial-distal direction, and the labial-lingual direction of the first digitized model includes: processing point cloud data contained in the first digital model according to a principal component analysis method to obtain a plurality of orthogonal first feature vectors; sorting the first feature vectors according to the sequence from the big feature value to the small feature value; and sequentially determining the first feature vectors positioned in the first order, the second order and the third order in the sorting result as a tooth long axis direction, a near-far middle direction and a labial-lingual direction. The long axis direction, the near-far middle direction and the labial-lingual direction of the tooth are characteristic directions of the tooth, so that the long axis direction, the near-far middle direction and the labial-lingual direction of the tooth are determined, namely the characteristic directions of the tooth are found, and the principal component analysis method is just the characteristic directions for finding data, so that the method is attached to the targets for determining the long axis direction, the near-far middle direction and the labial-lingual direction of the tooth, is favorable for accurately finding the long axis direction, the near-far middle direction and the labial-lingual direction of the tooth, and can fully utilize the solving algorithm of the existing principal component analysis method, thereby reducing the implementation difficulty, improving the processing efficiency and ensuring the accuracy.

Further, the processing the point cloud data contained in the first digitized model according to the principal component analysis method to obtain a plurality of orthogonal first feature vectors includes: matrixing point cloud data contained in the first digital model to obtain a first matrix; generating a first covariance matrix of the first matrix; and carrying out eigenvalue decomposition on the first covariance matrix to obtain a plurality of orthogonal first eigenvectors.

Further, before the generating the first covariance matrix of the first matrix, the method further comprises: performing decentration treatment on the first matrix; the generating a first covariance matrix of the first matrix includes: generating the first covariance matrix of the first matrix after decentralization. Through the decentralization processing, the data is simplified, which is beneficial to reducing the calculation difficulty and improving the processing efficiency.

Further, the determining the impedance center of the first digitized model includes: determining a center of gravity of the first digitized model; taking the center of gravity of the first digital model as the impedance center; or, along the long axis direction of the tooth, adjusting the gravity center of the first digital model, and taking the adjusted gravity center of the first digital model as the impedance center, wherein the impedance center is closer to the root lowest point of the digital model relative to the gravity center of the first digital model. The method is characterized in that a plurality of processing modes are provided to adapt to various different demands, wherein, compared with the continuous adjustment on the basis of the gravity center, the method has the advantages that the processing flow can be simplified by taking the gravity center as an impedance center, the processing efficiency is quickened, the setting mode of the tooth rotating accessory can be determined more quickly, the impedance gravity center is further adjusted on the basis of the gravity center, the phenomenon that the gravity center caused by the conversion between bone tissue and soft tissue in the tooth correcting process moves to a position close to the tooth root is considered, the determined coordinate system taking the impedance gravity center as the origin can be more attached to the tooth state after the correction is started, the deviation is smaller, and the determined target force application point and the target force application direction can be more accurate.

Further, the adjusting the center of gravity of the first digital model along the tooth long axis direction comprises: along the long axis direction of the tooth, the center of gravity of the first digital model is adjusted by the length of k1 by reference distance, wherein k1 is more than 1/3 and less than 2/5, and the reference distance is the distance between the center of gravity of the first digital model and the lowest point of the root of the tooth of the first digital model. The adjustment degree of the gravity center is restrained, and the fact that the target force application point and the target force application direction are determined due to overlarge adjustment or insufficient adjustment is avoided.

Further, the rotary attachment includes an attachment surface for attachment to the target tooth, the method further comprising: acquiring a second digital model of the rotating accessory; the determining a target pose of the rotating accessory on the rotating accessory addition side of the first digital model from the target point of application and the target direction of application comprises: determining the adding position of the rotary accessory according to the target force application point; determining a stress surface of the rotary accessory according to the target force application direction and the target force application point; determining a target direction of a connecting surface of the rotary accessory according to the adding position of the rotary accessory, the stress surface of the rotary accessory and a profile surface adding side of the first digital model at the position corresponding to the target force application point; and positioning the target pose according to the target direction and the adding position of the rotary accessory. When the rotary accessory is arranged, the arrangement position of the rotary accessory is considered, the arrangement direction of the rotary accessory on the profile surface adding side at the target force application point is also considered, the problem that the rotary accessory is not attached to the profile surface adding side surface at the target force application point due to random arrangement is avoided, and the stability of the rotary accessory arranged on the surface of the target tooth and the effect of transmitting correction force are improved.

Further, the determining the target direction of the connection surface of the rotating accessory according to the adding position of the rotating accessory, the stress surface of the rotating accessory and the adding side of the rotating accessory at the position corresponding to the target application point of the first digital model includes: determining the intersection line of the stress surface of the rotary accessory and the contour surface of the first digital model on the adding side of the rotary accessory; calculating the tangential direction of the intersection line at the target force application point; and determining the target direction of the connecting surface of the rotary accessory according to the tangential direction. The setting direction is determined based on the profile surface adding side at the target force application point, so that the rotary accessory can be more attached to the profile surface adding side surface at the target force application point, and the stability of the rotary accessory on the surface of the target tooth and the effect of transmitting correction force are improved.

Further, the method further includes, after applying the correction force to the rotating attachment, targeting a maximum ratio of moment components of the correction force twisting around the long axis of the tooth in a target direction, and before determining the target point of application and the target direction of application on the rotating attachment addition side of the first digital model, further including: determining a target area of the target force application point on the rotating accessory addition side of the first digital model according to the size information of the first digital model; the method for determining the target force application point and the target force application direction on the rotating attachment adding side of the first digital model with the maximum torque component ratio of the correction force twisting around the tooth long axis according to the target direction as the target after the correction force is applied to the rotating attachment comprises the following steps: and after the correction force is applied to the rotary accessory, the maximum ratio of moment components of the correction force which are twisted around the long axis of the tooth according to the target direction is taken as a target, and the target force application point and the target force application direction are determined in the target area. The target force application point and the target force application direction are determined relative to the whole surface of the rotary accessory adding side of the first digital model, and by reducing the possible areas of the target force application point, the data to be processed is reduced, the possible areas of the target force application point which are more suitable are favorably selected according to the state of the target teeth, the unsuitable areas are not considered any more, and the processing efficiency is favorably improved.

Further, the size information is a tooth position number, and the determining, on the rotating accessory addition side of the first digital model, a target area of the target application point according to the size information of the first digital model includes: determining a first threshold value, a second threshold value and a third threshold value according to the tooth position number corresponding to the first digital model, wherein the value range of the first threshold value is 2.0-3.0 mm, the value range of the second threshold value is 10.0-11.0 mm, and the value range of the second threshold value is 2.0-2.5 mm; determining, on the rotating attachment addition side of the first digitized model, the target area having a distance to the highest point of the incisal edge of the tooth in the direction of the long axis of the tooth greater than the first threshold, a distance to the lowest point of the gum line in the direction of the long axis of the tooth greater than the second threshold, and a distance to the furthest points on both sides of the digitized model in the mesial-distal direction greater than the third threshold. By finding a central area on the rotating attachment addition side of the first digitized model, the possibility of the target point of application being located at the edge of the first digitized model is avoided, thereby avoiding the impact on dental occlusion or the problem of difficulty in setting the rotating attachment based on the target point of application.

Further, the determining, on the rotating attachment addition side of the first digital model, the target area having a distance to a highest point of a tooth incisal edge in a tooth long axis direction greater than the first threshold, a distance to a lowest point of a gum line in a tooth long axis direction greater than the second threshold, and a distance to farthest points on both sides of the digital model in a mesial-distal direction greater than the third threshold, comprises: projecting the addition side of the rotary accessory of the first digital model onto a plane formed by the long axis direction and the near-far direction of the tooth to obtain a projection area; determining rectangular feasible areas with the distance from the tooth cutting edge highest point in the tooth long axis direction being larger than the first threshold, the distance from the tooth cutting edge lowest point in the tooth long axis direction being larger than the second threshold and the distance from the tooth cutting edge lowest point in the mesial-distal direction being larger than the third threshold in the digital model two sides; pulling up the rectangular feasible region along the direction of the lip-tongue side of the first digital model and the direction of the adding side of the rotary accessory close to the first digital model to obtain a three-dimensional feasible region; and determining an intersection of the three-dimensional feasible region and the rotating accessory adding side of the first digital model to obtain the target region.

Further, the determining, on the rotating attachment addition side of the first digital model, the target area having a distance to a highest point of a tooth incisal edge in a tooth long axis direction greater than the first threshold, a distance to a lowest point of a gum line in a tooth long axis direction greater than the second threshold, and a distance to farthest points on both sides of the digital model in a mesial-distal direction greater than the third threshold, comprises: determining a first boundary plane below the highest point of the incisal margin of the tooth in the long axis direction of the tooth and at a distance of the first threshold, a second boundary plane above the lowest point of the gum line in the long axis direction of the tooth and at a distance of the second threshold, a third boundary plane at a distance of the third threshold from the mesial-distal most point of the first digital model in the mesial-distal direction, and a fourth boundary plane at a distance of the third threshold from the mesial-distal most point of the first digital model in the mesial-distal direction; and determining an intersection of a space formed by the joint enclosure of the first boundary plane, the second boundary plane, the third boundary plane and the fourth boundary plane and the rotating accessory adding side of the first digital model to obtain the target area.

Further, the method further comprises, prior to determining the target pose of the rotating accessory on the rotating accessory addition side of the first digital model from the target point of application and the target direction of application, the method further comprising: translating the target force application point away from the target tooth along the labial-lingual direction by a preset distance along a normal vector of an outer contour surface of the rotary accessory addition side of the first digital model at the center, wherein the preset distance is k2, and the thickness of the tooth accessory along the labial-lingual direction is more than 0.25 and less than 0.8; the determining a target pose of the rotating accessory on the rotating accessory addition side of the first digital model from the target point of application and the target direction of application comprises: and determining the target pose of the rotary accessory on the rotary accessory adding side of the digital model according to the translated target force application point and the target force application direction. Because the rotating accessory has a certain thickness, and the correction force of the shell-shaped correction device is applied through the contact surface of the shell-shaped correction device and the rotating accessory, the situation that the correction force is applied by the shell-shaped correction device through the rotating accessory can be more accurately simulated through translating the target application point, and the setting position and direction of the selected accessory, namely the target pose, can be more accurately determined.

To achieve the above object, an embodiment of the present invention further provides a method for manufacturing a dental appliance, including: according to the setting method of the tooth rotating accessory, the tooth accessory is set on the digital model to obtain a digital orthodontic model; generating a shell-shaped dental appliance from the digitized orthodontic model.

Further, the generating a shell-like dental appliance from the digital orthodontic model includes: manufacturing a male die of the appliance according to the digital orthodontic model; obtaining a shell-shaped dental appliance comprising a tooth shape by hot-press forming on a male die of the appliance; a shell dental appliance capable of receiving teeth is cut on the shell dental appliance containing tooth shapes along or adjacent to the gum line.

Further, the generating a shell-like dental appliance from the digital orthodontic model includes: generating a digital appliance model matched with the digital orthodontic model; and manufacturing the shell-shaped dental appliance through an additive manufacturing process according to the data information corresponding to the digital appliance model.

In order to achieve the above object, an embodiment of the present invention further provides a dental appliance system, including a plurality of shell-shaped appliances, where the plurality of shell-shaped appliances includes at least a first shell-shaped appliance, and the first shell-shaped appliance includes at least one tooth-receiving cavity, where the tooth-receiving cavity is provided with an accessory-receiving cavity, and the tooth-receiving cavity is used for receiving teeth to be rotated; the tooth correcting system at least comprises an accessory which is arranged on the target tooth according to the setting method of the tooth rotating accessory, when a patient wears the first shell-shaped correcting device, the rotating accessory is meshed with an accessory accommodating cavity on the first shell-shaped correcting device, and correcting force is generated on the target tooth; the rotation target of the target teeth is realized by overlapping a plurality of shell-shaped appliances which are worn by a patient in sequence.

To achieve the above object, an embodiment of the present invention further provides a tooth attachment setting device, including: the acquisition module is used for acquiring a first digital model of a target tooth, wherein the target tooth is a tooth to be corrected by adding a rotary accessory; the processing module is used for determining a target force application point and a target force application direction on the rotating accessory adding side of the first digital model by taking the maximum torque component ratio of the correction force which twists around the long axis of the tooth according to the target direction after the correction force is applied to the rotating accessory, wherein the target direction is clockwise or anticlockwise, and the correction force is the force applied to the rotating accessory by the shell-shaped correction device when the shell-shaped correction device is meshed with the rotating accessory arranged on the target tooth; and the setting module is used for determining a target pose of the rotary accessory on the rotary accessory adding side of the first digital model according to the target application point and the target application direction so as to set the rotary accessory on the rotary accessory adding side of the first digital model based on the target pose.

To achieve the above object, an embodiment of the present invention further provides an electronic device, including: at least one processor; and a memory communicatively coupled to the at least one processor; wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform a method of setting a dental rotational attachment as described above or to perform a method of manufacturing a dental appliance as described above.

To achieve the above object, embodiments of the present invention also provide a computer-readable storage medium storing a computer program which, when executed by a processor, implements the method of setting a dental rotary accessory as described above, or implements the method of manufacturing a dental appliance as described above.

Drawings

One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements, and in which the figures of the drawings are not to be taken in a limiting sense, unless otherwise indicated.

FIG. 1 is a flow chart of a method of setting a dental rotational accessory provided in an embodiment of the present invention;

FIG. 2 is a schematic illustration of a target tooth force condition in a method of setting a tooth rotation attachment according to one embodiment of the present invention shown in FIG. 1;

FIG. 3 is a schematic view of a coordinate system for describing a target posture in a method of setting a dental rotary accessory according to an embodiment of the present invention shown in FIG. 1;

FIG. 4 is a schematic view of a partial coordinate system of a rotary attachment in the method for setting up a dental rotary attachment according to an embodiment of the present invention shown in FIG. 1;

FIG. 5 is a schematic diagram of a coordinate system for describing a target font and a local coordinate system of a rotary attachment in a global coordinate system of a dentition model in a method for setting a rotary attachment of teeth according to an embodiment of the present invention shown in FIG. 1;

FIG. 6 is a schematic view of the rotary attachment set to the first digital model in the method of setting a dental rotary attachment provided in one embodiment of the invention shown in FIG. 1;

FIG. 7 is a flow chart of a method of setting a dental rotational accessory provided in another embodiment of the present invention;

FIG. 8 is a schematic view of rectangular viable areas in the method of setting up a dental rotational attachment provided in an embodiment of the invention shown in FIG. 7;

FIG. 9 is a flow chart of a method of setting a dental rotational accessory provided in another embodiment of the present invention;

FIG. 10 is a flow chart of a method of manufacturing an appliance provided in another embodiment of the present invention;

FIG. 11 is a schematic view of a tooth-rotating attachment setting device according to another embodiment of the present invention;

fig. 12 is a schematic structural diagram of an electronic device according to another embodiment of the present invention.

Detailed Description

As known from the background art, the existing setting method of the tooth torsion attachment still needs to be implemented manually, which cannot be fully automated.

It was found by analysis that one of the reasons for the occurrence of the above problems is: the various methods for setting the tooth attachment for achieving the tooth torsion are generally implemented by continuously judging whether the setting position of the tooth rotating attachment on the tooth based on experience definition is reached or not and adjusting the setting position, for example, in the "pressure attachment design method, appliance forming method, system and storage medium", the ideal setting position of the tooth rotating attachment on the tooth is defined as follows: the position where the difference between the resultant moment and pressure acting on the teeth and the resultant moment and pressure acting on the teeth by the appliance without the attachment is smaller than a preset value, wherein the acquisition of the preset value and the corresponding physical meaning are not clear enough and depend on the experience of researchers.

To solve the above-mentioned problems, the embodiments of the present invention provide a method for setting a tooth rotating attachment, which is defined as: after the correction force is applied to the rotary accessory on the adding side of the rotary accessory, the pose with the largest torque component ratio of the correction force twisting around the tooth long axis according to the target direction can be realized, so that the twisting around the tooth long axis can be realized to the greatest extent based on the pose, the target tooth can be twisted to a desired position more easily, and the efficiency is higher. At the moment, the position design of the selected accessory is summarized into a stress analysis problem, and the application position and direction of the force are determined through the position with the largest contribution of the force to the rotation of the teeth, so that the pose of the accessory is determined, relevant parameters are not required to be set based on experience in the process of determining the target application point and the target application direction, the manual experience is not required to be relied on, and the automation of accessory setting is realized.

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, it will be understood by those of ordinary skill in the art that in various embodiments of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the claimed technical solution of the present invention can be realized without these technical details and various changes and modifications based on the following embodiments.

The following embodiments are divided for convenience of description, and should not be construed as limiting the specific implementation of the present invention, and the embodiments can be mutually combined and referred to without contradiction.

An aspect of the present invention provides a method for setting a tooth rotation attachment. The flow is shown in fig. 1, and at least comprises the following steps:

step 101, a first digitized model of a target tooth is acquired.

In this embodiment, the target tooth is a tooth to be corrected by adding a rotating accessory, that is, the target tooth is a tooth to be corrected by twisting. The "first" of the first digital model has no actual meaning, mainly for distinguishing from the second digital model of the subsequent rotating attachment, i.e. the first digital model is the digital model of the target tooth.

It should be noted that the number of the target teeth is not limited in this embodiment, and may be a single tooth or a plurality of teeth, which mainly depends on the need for correction. The method of acquiring the first digitized model is not limited in this embodiment either, and the first digitized model may be obtained by downloading an existing model, or may be obtained by scanning a real tooth with an X-ray or cone-beam computed tomography (Cone beam Computer Tomography, CBCT), magnetic resonance imaging (Nuclear Magnetic Resonance Imaging, MRI), or laser.

Step 102, determining a target force application point and a target force application direction on the rotating accessory adding side of the first digital model with the maximum torque component ratio of the correction force twisting around the tooth long axis according to the target direction after the correction force is applied to the rotating accessory.

In this embodiment, the target direction is clockwise or counterclockwise, and the correction force is the force applied by the shell-shaped appliance to the rotating attachment when the shell-shaped appliance is engaged with the rotating attachment provided on the target tooth.

In some examples, the rotating accessory is a digitized model of a scan of a solid rotating accessory, which scan may be with X-rays, CBCT, or the like.

In other examples, the rotary accessory is obtained from an accessory library, wherein a digitalized model of various tooth accessories is pre-stored in the accessory library, the tooth accessories may not be limited to the rotary accessory, and the rotary accessory may have model differences, and the model may correspond to tooth position information or relate to tooth diameters and the like, which will not be described in detail herein.

It should be noted that, whether obtained by scanning or obtained from an accessory library, the obtained rotary accessory has the characteristic of non-deformability, i.e. the size and shape are fixed.

It should be noted that, the target direction is mainly used to describe the expected torsion direction around the long axis direction of the tooth, and considering that the tooth can be rotated around the long axis of the tooth in both a clockwise direction and a counterclockwise direction to achieve the target position, for example, a certain tooth rotates around the long axis of the tooth by 30 ° in a clockwise direction, which corresponds to rotating around the long axis of the tooth by 330 ° in a counterclockwise direction, the target direction can be further defined generally, for example, the rotation angle between the current state of the target tooth and the state after correction around which direction is smaller, which is the target direction, and the like.

It will be appreciated that step 102 actually describes a model that uses the point of application and the direction of application as variables, uses the added side of the rotating attachment where the point of application is located as a constraint condition, uses the maximum ratio of the moment component of the correction force that twists around the long axis of the tooth in the target direction to the total moment as a target function, and determines the optimal solution of the model, thereby obtaining the target point of application and the target direction of application. Considering that moment components and total moment are involved in the model, i.e. there is moment decomposition, and the decomposition based on the coordinate system is less difficult to achieve, in some embodiments, step 102 may be achieved by: determining a local coordinate system of the first digital model; generating a target model under a local coordinate system of the first digital model, wherein the target model takes a force application point and a force application direction as variables, takes a rotating accessory adding side of the force application point positioned on the first digital model as a constraint condition, and takes the maximum ratio of a moment component of correcting force twisting around a tooth long axis along the target direction to the total moment as a target function; and determining an optimal solution of the target model to obtain a target force application point and a target force application direction. Specifically, referring to FIG. 2, when the correction force F is applied at point O', its moment arm is vector R, thus producing a total force Moment m=f×r, where vector R isThe correction force F is force with a direction, and then moment components of the total moment M on the long axis of the tooth are decomposed to obtain M ', so that the ratio of the moment components of the correction force which are twisted around the long axis of the tooth according to the target direction to the total moment is M '/M, wherein the shaded part in the graph 2 is a force application surface, and the force application point O ' is positioned on the force application surface.

Considering that one feature of step 102 is a moment component that twists around the long axis of the tooth according to the target direction, it will involve a moment decomposition of the total moment about the long axis of the tooth, so if the long axis of the tooth is taken as one coordinate axis direction in the local coordinate system, the coordinate of the total moment under the local coordinate system represents a moment decomposition result that the total moment is actually twisted around the long axis of the tooth, and no additional solution of moment decomposition is needed, thereby reducing the difficulty of constructing and solving the implementation objective function. Thus, in some embodiments, determining the local coordinate system of the first digitized model may be accomplished by: determining the tooth long axis direction, the near-far middle direction and the labial lingual direction of the first digital model; determining an impedance center of the first digitized model; and generating a local coordinate system of the first digital model by taking the determined tooth long axis direction, the determined near-far middle direction and the determined labial lingual direction as three axes of the coordinate system and taking the impedance center as an origin of the coordinate system. Thereby obtaining the local coordinate system of the first digital model with the tooth long axis direction as one coordinate axis direction.

At this time, according to the difference of the target directions, the target model may have two kinds of representations, specifically as follows:

1. the target direction is anticlockwise, and the target model is:

2. the target direction is clockwise, and the target model is:

where F (x, y, z) =0 is a curved surface expression of the rotating accessory addition side of the digitized model in the local coordinate system of the digitized model, (a, b, c) × (x, y, z) represents a cross operation of vector (a, b, c) and vector (x, y, z).

It should be noted that, when constructing a local coordinate system of a tooth model, the tooth long axis direction is usually taken as the Z axis, the above object model is described only in the case of taking the tooth long axis direction as the Z axis of the first digital model, and in other embodiments, the object model may have different representations due to different coordinate axes defined by the tooth long axis direction of the coordinate system, such as when the tooth long axis is defined as the X axis (or the Y axis),the molecules in (a) are replaced by |mx| (or |my|), or the tooth long axis direction is not used as one coordinate axis of the local coordinate system of the first digital model, so that (Mx, my, mz) needs to be decomposed according to the tooth long axis direction and the other two directions perpendicular to the tooth long axis direction, which are not described in detail herein.

In addition, with respect to the specific expression of the above object model, in consideration of the object function,the effect of the correction force on the moment is counteracted, i.e. the magnitude of the correction force does not affect the solving of the objective function, so that the correction force can be regarded as a unit force, but this does not mean that the correction force can only be a unit force, in other embodiments the correction force in the objective function can also have an exact magnitude.

Further, determining the long axis direction, the mesial-distal direction, and the labial-lingual direction of the tooth may be accomplished by: processing point cloud data contained in the first digital model according to a principal component analysis method to obtain a plurality of orthogonal first feature vectors; sorting the first feature vectors according to the sequence of the feature values from big to small; and sequentially determining the first feature vectors positioned in the first order, the second order and the third order in the sorting result as the long axis direction, the near-far middle direction and the labial lingual direction of the teeth. The first digital model is used as a tooth model, the tooth long axis and the near-far middle labial-lingual direction are characteristic directions, so that the tooth long axis and the near-far middle labial-lingual direction are determined, namely the characteristic directions of teeth are found, the principal component analysis method is just the characteristic directions for finding data, so that the tooth long axis and the near-far middle labial-lingual direction are attached to a target for determining the tooth long axis and the near-far middle labial-lingual direction, and the tooth long axis and the near-far middle labial-lingual direction are the optimal characteristic directions of teeth, so that the maximum three characteristics obtained by the principal component analysis method are the tooth long axis and the near-far middle labial-lingual direction.

The method comprises the steps of processing point cloud data contained in a first digital model according to a principal component analysis method to obtain a plurality of orthogonal first feature vectors, wherein the first feature vectors can be realized in the following manner: matrixing point cloud data contained in the first digital model to obtain a first matrix; generating a first covariance matrix of the first matrix; and carrying out eigenvalue decomposition on the first covariance matrix to obtain a plurality of orthogonal first eigenvectors.A is a first matrix, and n is the number of points contained in the point cloud data contained in the first matrix.

It should be noted that, the feature vectors obtained by the feature decomposition processing of the symmetric matrix are orthogonal to each other, and the covariance matrix is the symmetric matrix, so that the first covariance matrix is subjected to the feature decomposition to obtain a plurality of first feature vectors orthogonal to each other.

In some examples, prior to generating the first covariance matrix of the first matrix, further comprising: and performing decentration treatment on the first matrix. Accordingly, generating a first covariance matrix of the first matrix comprises: a first covariance matrix of the first matrix after decentralization is generated. The decentralization treatment comprises the following steps:n is the number of points in the point cloud data contained in the first digital model, and x _i 、y _i And z _i Is the coordinates of the i-th point. Therefore, through the decentralization processing, the calculation difficulty of the covariance matrix and the difficulty of characteristic decomposition are reduced.

In some embodiments, determining the impedance center of the first digitized model may be accomplished by: determining a center of gravity of the first digitized model; the center of gravity of the first digitized model is taken as the impedance center. Wherein, under the condition that the density information of the target teeth is not available, the center of gravity can be determined by taking the center, namely, assuming that the density of the target teeth is uniformn is the number of points in the point cloud data contained in the first digital model, and x _i 、y _i And z _i Coordinates of the i-th point; in case of density information of the target tooth, it can be solved according to the density information of the target tooth in combination with the point cloud data, i.e. +.>And will not be described in detail herein.

In other embodiments, the efficiency is improved relative to the direct use of the center of gravity as the center of impedance, and it is also contemplated that the center of gravity of the tooth digital model obtained based on bone tissue will change as the periodontal ligament changes around the soft tissue and bone tissue of the teeth during the appliance, wherein the portion of the tooth digital model near the periodontal ligament will increase as the soft tissue is transformed into bone tissue during the appliance, such that the actual center of gravity moves downward, and the center of gravity is unstable and moves downward toward the root nadir during the subsequent appliance. Therefore, the subsequent offset problem is also considered in the process of determining the gravity center, so that the deviation of the determined coordinate system in the subsequent correction process is reduced, and the determined target force application point and the determined target force application direction are more accurate. At this time, the determination of the impedance center may also be achieved by: and determining the gravity center of the first digital model, adjusting the gravity center of the first digital model along the long axis direction of the teeth, and taking the adjusted gravity center of the first digital model as an impedance center, wherein the impedance center is closer to the lowest point of the tooth root of the digital model relative to the gravity center of the first digital model.

In some examples, adjusting the center of gravity of the first digitized model along the long axis of the tooth may be accomplished by: along the long axis direction of the tooth, the center of gravity of the first digital model is adjusted by the length of k1 reference distance, wherein k1 is more than 1/3 and less than 2/5, and the reference distance is the distance between the center of gravity of the first digital model and the lowest point of the root of the first digital model. Therefore, the adjustment amplitude of the gravity center is constrained based on k1, and the problems of insufficient adjustment amplitude or excessive adjustment are avoided. Specifically, under the point cloud data coordinates of the first digital model, assuming that the determined tooth long axis direction is γ= (c 1, c2, c 3), the center of gravity of the first digital model is (x 0, y0, z 0), and the reference distance is d0, the coordinates of the impedance center of gravity (x 1, x2, x 3) = (x 0-c1 d0, y0-c2 d0, z0-c3 d 0).

And step 103, determining the target pose of the rotary accessory on the rotary accessory adding side of the first digital model according to the target force application point and the target force application direction so as to set the rotary accessory on the rotary accessory adding side of the first digital model based on the target pose.

In this embodiment, the target pose is a pose in which the rotating attachment is disposed on the first digital model and is capable of applying an corrective force to the first digital model along the target force application direction at the target force application point. The target pose includes a target position and a target direction of the rotating accessory.

It will be appreciated that the rotary attachment is required to form a connection with the first digital model to transfer the orthodontic force to the first digital model, and therefore the rotary attachment includes a connection surface for connection with the target tooth, and the method of setting the rotary attachment further comprises: a second digitized model of the rotating accessory is obtained. Accordingly, step 103 may be implemented as follows: determining the adding position of the rotary accessory according to the target force application point; determining a stress surface of the rotary accessory according to the target force application direction and the target force application point; determining a target direction of a connecting surface of the rotary accessory according to the adding position of the rotary accessory, the stress surface of the rotary accessory and the profile surface adding side of the position of the first digital model corresponding to the target force application point; and positioning the target pose according to the target direction and the adding position of the rotary accessory. The force receiving surface is a plane passing through the target force application point and the normal vector at the target force application point is the target force application direction, and the addition position may be a position where the rotating attachment can cover the target force application point after the rotating attachment is added at the position, or a position where the projection of the center of the rotating attachment on the tooth after the rotating attachment is added at the position is the target force application point, and the like.

Wherein, in some examples, determining the target direction of the connection surface of the rotating accessory according to the adding position of the rotating accessory, the stress surface of the rotating accessory and the rotating accessory adding side at the corresponding target application point of the first digital model can be achieved by the following ways: determining the intersection line of the stress surface of the rotary accessory and the contour surface of the first digital model on the adding side of the rotary accessory; calculating the tangential direction of the intersection line at the target force application point; the target direction of the connection surface of the rotating accessory is determined according to the tangential direction. For example, the force-bearing surface is G (x, y, z): a (x-x 0) +b (y-y 0) +c (z-z 0) =0, (a, b, c) is the target force-application direction, (x 0, y0, z 0) is the target force-application point, and the intersection line of the force-bearing surface G (x, y, z) and the rotating accessory-adding side of the first digital model is F (x, y, z) is determinedThen determine intersection +.>Tangent at (x 0, y0, z 0)Thereby according to tangent +.>Determination of the purposeAnd (5) marking the direction. Finally, the connection surface of the rotary accessory can be placed at the position of crossing the target force application point according to the target direction.

In order to facilitate a better understanding of the above-described placement of the rotating accessory at the target point of application according to the target direction, an example will be described below.

Before placing the rotary accessory, the current pose of the rotary accessory needs to be determined firstly, and the method is specific: processing point cloud data of a connection surface of the rotating accessory based on a principal component analysis method to obtain a plurality of orthogonal second feature vectors; sorting the second feature vectors from large to small according to the magnitudes of the feature values; the second feature vectors located in the first order and the second order in the sorting result are taken as the local coordinate X axis and Y axis of the point cloud data of the rotary accessory, the center of the point cloud data of the force application surface of the rotary accessory is taken as the origin of coordinates to construct a local coordinate system A of the rotary accessory, so that the initial pose of the rotary accessory can be represented based on the coordinate system A, at this time, referring to FIG. 3, the coordinate system A is a coordinate system O ' -X ' Y ' Z ', wherein O ' is the gravity center ' of the rotary accessory W, the X ' axis and the Y ' axis are determined by a principal component analysis method, and the Z axis ' is determined based on the principle of a right-hand coordinate system when the X ' axis and the Y ' are determined.

Accordingly, the target pose may also be described by a local coordinate system, such that the rotating accessory is set onto the first digitized model based on a mapping between the coordinate systems. At this time, the description of the target pose may be achieved as follows: the coordinate system B is constructed with the center of the urging surface as the origin, the target direction as the X axis, and the target urging direction as the Z axis, and at this time, referring to fig. 4, the coordinate system B is the coordinate system O ' "-X '" Y ' "Z '" in which the axis X ' "points to the determined target direction, the Z '" axis is the target urging direction, and Y ' "is determined based on the right-hand coordinate system principle in the case of determining the X '" axis and the Z ' ".

And then, according to the mapping relation between the coordinate system A and the coordinate system B, mapping the rotating accessory to the local coordinate system B, and realizing the setting of the rotating accessory. In some examples, first, a rotation matrix and a translation matrix between the coordinate system A and a global coordinate system of a dentition model corresponding to the target tooth in the coordinate system B are respectively determined, then, a mapping relation from the coordinate system A to the coordinate system B is obtained based on the two sets of rotation matrices and the translation matrices, and finally, point cloud data of the rotating accessory is mapped into the coordinate system B.

Of course, in other cases, it is also possible to transfer both the coordinate system A and the coordinate system B to the global coordinate system of the dentition model by coordinate system conversion, in which case the coordinate system A and the coordinate system B are in the global coordinate system 0 of the dentition model ₀ -X ₀ Y ₀ Z ₀ As shown in fig. 5, then coordinate system a is converted to coordinate system B to coincide to set the rotation matrix to the target tooth surface as shown in fig. 6.

That is, the global coordinate system of the dentition model is taken as the reference coordinate system, so that the relation between the coordinate system A and the coordinate system B is constructed, the difficulty in determining the mapping relation between the coordinate system A and the coordinate system B is reduced, and the processing efficiency is improved.

In some embodiments, as shown in fig. 7, the method for setting a tooth rotation attachment further includes, prior to step 102:

Step 104, determining a target area of the target application point on the rotating attachment adding side of the first digital model according to the size information of the first digital model.

Accordingly, step 102 is: and after the correction force is applied to the rotating accessory, the maximum ratio of moment components of the correction force which rotate around the long axis of the tooth according to the target direction is taken as a target, and the target force application point and the target force application direction are determined in the target area.

In some embodiments, the size information is a dental number, at which point step 104 may be implemented as follows: determining a first threshold value, a second threshold value and a third threshold value according to the tooth position number corresponding to the first digital model, wherein the value range of the first threshold value is 2.0-3.0 mm, the value range of the second threshold value is 10.0-11.0 mm, and the value range of the third threshold value is 2.0-2.5 mm; on the rotating attachment addition side of the first digital model, a target area is determined in which the distance from the tooth longitudinal axis to the highest point of the tooth incisal edge is greater than a first threshold, the distance from the tooth longitudinal axis to the lowest point of the gum line is greater than a second threshold, and the distance from the tooth longitudinal axis to the farthest points on both sides of the digital model is greater than a third threshold. More specifically, the relationship between the first, second, and third thresholds and the dental position is shown in the following table:

	1-2 teeth	Tooth number 3	4-5 teeth
				First threshold/mm	2.0～2.5	2.5～3.0mm	2.2～2.5
Second threshold/mm	10.0～10.5	10.5～11.0	10.0～10.5
				Third threshold/mm	2.0～2.5	2.0～2.5	2.0～2.5

It should be noted that, the above table only shows the teeth 1-5, and does not show the teeth 6-7, mainly considering that there is usually no need for torsion correction when correcting the teeth 6-7, and of course, if there is a need for torsion correction on the teeth 6-7, the value ranges of the first threshold, the second threshold and the third threshold can be determined approximately based on the above table.

Wherein, in some examples, on the rotating attachment addition side of the first digital model, determining a target area with a distance to the highest point of the incisal edge of the tooth in the direction of the long axis of the tooth greater than a first threshold, a distance to the lowest point of the gum line in the direction of the long axis of the tooth greater than a second threshold, and a distance to the farthest points on both sides of the digital model in the direction of the near and far center greater than a third threshold can be achieved by: projecting the addition side of the rotary accessory of the first digital model onto a plane formed by the long axis direction and the near-far middle direction of the tooth to obtain a projection area, namely the tooth profile shown in figure 8, wherein the Z axis points to the long axis direction of the tooth and the Y axis points to the near-far middle direction; determining rectangular viable areas in the projection area, wherein the distance from the tooth longitudinal axis direction to the highest point of the tooth incisal edge is greater than a first threshold value, the distance from the tooth longitudinal axis direction to the lowest point of the gum line is greater than a second threshold value, the distance from the tooth longitudinal axis direction to the farthest points on two sides of the digital model is greater than a third threshold value, taking the example that the first threshold value is not 2mm, the second threshold value is 2.5 mm and the third threshold value is 2mm, and obtaining the rectangular viable areas as shown in the shaded part of fig. 8, wherein d1 represents the first threshold value, d2 represents the second threshold value and d3 represents the third threshold value; pulling up the rectangular feasible region along the direction of the labial and lingual sides of the first digital model and the direction of the adding side of the rotary accessory close to the first digital model to obtain a three-dimensional feasible region, namely pulling up along the direction C shown in fig. 8; and determining an intersection of the three-dimensional feasible region and the rotating accessory adding side of the first digital model to obtain a target region. In particular, the tooth lifting length of 1-3 is not less than 10 mm, and the tooth lifting length of 4-5 is not less than 30 mm, so that the surface of the rotary accessory adding side of the first digital model can be completely included in the three-dimensional feasible region.

In other examples, determining a target area on the rotating attachment addition side of the first digitized model that is greater than a first threshold distance from the highest point of the incisal edge of the tooth in the direction of the long axis of the tooth, greater than a second threshold distance from the lowest point of the gum line in the direction of the long axis of the tooth, and greater than a third threshold distance from the furthest points on either side of the digitized model in the mesial-distal direction may be accomplished by: determining a first boundary plane which is lower than the highest point of the incisal edge of the tooth in the long axis direction of the tooth and is a first threshold value, a second boundary plane which is higher than the lowest point of the gum line in the long axis direction of the tooth and is a second threshold value, a third boundary plane which is a third threshold value in the mesial-distal direction from the mesial-distal most point of the first digital model, and a fourth boundary plane which is a third threshold value in the mesial-distal direction from the mesial-distal most point of the first digital model; and determining an intersection of a space formed by the joint enclosure of the first boundary plane, the second boundary plane, the third boundary plane and the fourth boundary plane and the rotating accessory adding side of the first digital model to obtain a target area.

In some embodiments, as shown in fig. 9, the method for setting a tooth rotation attachment further includes, prior to step 103:

And 105, adding a normal vector of the outer contour surface of the side at the center along the rotary accessory of the first digital model, and translating the target force application point away from the target tooth by a preset distance along the labial-lingual direction.

In this embodiment, the preset distance is k2, which is the thickness of the tooth attachment in the labial-lingual direction, 0.25 < k2 < 0.8.

Accordingly, step 103 is: and determining the target pose of the rotary accessory on the rotary accessory adding side of the digital model according to the translated target force application point and the target force application direction.

It can be understood that the rotating accessory has a thickness, and the correction force applied to the rotating accessory is not actually located on the tooth surface, namely the first digital model surface in the correction process, so that the influence of the rotating accessory on the application of the correction force is considered, and the target application point is lifted in a direction away from the first digital model surface, so that the state of the rotating accessory is more similar to the correction force applied when the shell-shaped correction carrying the rotating accessory is actually worn, and the accuracy of determining the target application point is improved.

In another aspect, the present invention provides a method for manufacturing a dental appliance, as shown in fig. 10, including:

in step 1001, according to the method for setting the tooth rotation accessory, the tooth accessory is set on the digital model, so as to obtain the digital orthodontic model.

The method of setting a dental rotary accessory in this embodiment is the method of setting a dental rotary accessory as described in any of the above embodiments.

Step 1002, generating a shell dental appliance from the digitized orthodontic model.

In some examples, generating a shell-shaped dental appliance from a digital orthodontic model can be accomplished by: manufacturing a male die of the appliance according to the digital orthodontic model; obtaining a shell-shaped dental appliance comprising a tooth shape by hot-press forming on a male die of the appliance; a shell dental appliance capable of receiving teeth is cut on a shell dental appliance containing the shape of the teeth along or adjacent to the gum line. Namely, after the digital orthodontic model is obtained, the digital orthodontic model is subjected to data extraction and conversion, the digital orthodontic model data is converted into the specification data for manufacturing the appliance male die, then the manufacturing of the appliance male die is completed according to the obtained specification data, and then an appliance membrane made of transparent polymer material (elastic polymer such as polycarbonate) is pressed on the appliance male die through a positive pressure film pressing technology by means of a hot-press forming device to form a shell, so that the shell-shaped dental appliance containing the tooth shape is manufactured. And the manufacturing efficiency and accuracy are greatly improved through a hot press forming mode. In order to enable the manufactured dental appliance to perform a good appliance function, it is necessary to ensure that the dental appliance can be used normally, and therefore, on the shell dental appliance formed by hot pressing, the shell dental appliance is cut along the gum line or at the position adjacent to the gum line, so that the cut shell dental appliance can accommodate the teeth of a patient, and further, the manufacturing of the shell dental appliance is completed. In other examples, generating a shell-shaped dental appliance from a digital orthodontic model may also be accomplished by: generating a digital appliance model matched with the digital orthodontic model; and manufacturing the shell-shaped dental appliance through an additive manufacturing process according to the data information corresponding to the digital appliance model. Namely, after the creation of the digital orthodontic model is completed, a digital appliance matched with the digital orthodontic model is manufactured according to the digital orthodontic model, wherein the digital appliance comprises a containing space for containing the digital orthodontic model.

In practical application, the process of generating the digital appliance model matched with the digital orthodontic model can be as follows: on the digital orthodontic model, a matrix model of the appliance is obtained through curved surface thickening; and then calculating the size and direction of the needed correction force and moment according to different movement directions and movement amounts of each tooth, determining the shape and size of a local structure or an accessory of the needed correction device according to a thermodynamic model of the shape memory polymer material, and combining the local structure and the matrix model to obtain the three-dimensional digital correction device model of the finished invisible correction device model. When the shell-shaped dental appliance is manufactured by an additive manufacturing process, the shell-shaped dental appliance can be manufactured by a rapid prototyping technology, the specification data of the digital dental appliance are converted into a data format corresponding to the rapid prototyping technology, and then the manufacturing is completed by the rapid prototyping technology. Wherein, the rapid prototyping technique that adopts includes: stereolithography (StereoLithography, STL), laser rapid prototyping (Stereo lithography Apparatus, SLA), layered entity fabrication 10 (Laminated Object Manufacturing, LOM), laser selective sintering (Selected Laser Sintering, SLS), fused deposition fabrication (Fused Deposition Modeling, FDM), three-dimensional printing fabrication (Three DimensionalPrinting,3 DP), and the like, without limitation to the specific rapid prototyping techniques employed.

In addition, in the process of creating the digital appliance, auxiliary instruments required to be used in the orthodontic process can be considered, and according to the creation of the digital model of the auxiliary instruments such as the auxiliary appliance and the fastener which are required to be adopted, the digital appliance comprises a containing space for containing the digital model corresponding to the auxiliary instrument, and the generated digital appliance comprises a containing space for containing the digital orthodontic model and can also comprise a containing space for containing the digital model corresponding to the auxiliary instrument.

The above steps of the methods are divided, for clarity of description, and may be combined into one step or split into multiple steps when implemented, so long as they include the same logic relationship, and they are all within the protection scope of this patent; it is within the scope of this patent to add insignificant modifications to the algorithm or flow or introduce insignificant designs, but not to alter the core design of its algorithm and flow.

In another aspect, an embodiment of the present invention provides a dental appliance system, including:

the tooth appliance comprises a plurality of shell-shaped appliances, wherein the shell-shaped appliances at least comprise a first shell-shaped appliance, the first shell-shaped appliance at least comprises a tooth accommodating cavity, an accessory accommodating cavity is arranged on the tooth accommodating cavity, and the tooth accommodating cavity is used for accommodating teeth to be rotated; the tooth correcting system at least comprises an accessory which is arranged on the target tooth according to the setting method of the tooth rotating accessory, when a patient wears the first shell-shaped correcting device, the rotating accessory is meshed with an accessory accommodating cavity on the first shell-shaped correcting device, and correcting force is generated on the target tooth; the rotation target of the target teeth is realized by overlapping a plurality of shell-shaped appliances which are worn by a patient in sequence.

The tooth correction system can correct only the teeth of a single jaw, can correct the upper jaw and the lower jaw simultaneously, is used for correcting the upper jaw or the lower jaw by using the shell-shaped tooth correction device with tooth wrapping performance only or using the conventional shell-shaped tooth correction device without corresponding auxiliary retention part, and can be specifically selected and used according to the actual intraoral condition of a patient.

In another aspect, an embodiment of the present invention further provides a device for setting a tooth attachment, as shown in fig. 11, including:

the obtaining module 1101 is configured to obtain a first digital model of a target tooth, where the target tooth is a tooth to be corrected by adding a rotating attachment.

The processing module 1102 is configured to determine, on a rotating attachment adding side of the first digital model, a target force application point and a target force application direction with a maximum ratio of torque components of the correcting force twisted around a long axis of the tooth according to a target direction after the correcting force is applied to the rotating attachment, where the target direction is a clockwise direction or a counterclockwise direction, and the correcting force is a force applied to the rotating attachment by the shell-shaped appliance when the shell-shaped appliance is meshed with the rotating attachment provided on the target tooth.

A setting module 1103 for determining a target pose of the rotating accessory on the rotating accessory addition side of the first digitized model according to the target point of application and the target direction of application to set the rotating accessory on the rotating accessory addition side of the first digitized model based on the target pose.

It is to be noted that this embodiment is an apparatus embodiment corresponding to a method embodiment of a method of setting a tooth rotation attachment, and this embodiment can be implemented in cooperation with this method embodiment. The related technical details mentioned in this embodiment of the method are still valid in this embodiment, and in order to reduce repetition, they are not described here again. Accordingly, the related technical details mentioned in the present embodiment may also be applied in the method embodiment.

It should be noted that, each module involved in this embodiment is a logic module, and in practical application, one logic unit may be one physical unit, or may be a part of one physical unit, or may be implemented by a combination of multiple physical units. In addition, in order to highlight the innovative part of the present invention, units less closely related to solving the technical problem presented by the present invention are not introduced in the present embodiment, but it does not indicate that other units are not present in the present embodiment.

Another aspect of the embodiment of the present invention further provides an electronic device, as shown in fig. 12, including: at least one processor 1201; and a memory 1202 communicatively coupled to the at least one processor 1201; the memory 1202 stores instructions executable by the at least one processor 1201, the instructions being executable by the at least one processor 1201 to enable the at least one processor 1201 to perform the method of setting a dental rotary accessory or the method of manufacturing a dental appliance described in any of the method embodiments described above.

Where the memory 1202 and the processor 1201 are connected by a bus, the bus may comprise any number of interconnected buses and bridges, the buses connecting the various circuits of the one or more processors 1201 and the memory 1202. The bus may also connect various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further herein. The bus interface provides an interface between the bus and the transceiver. The transceiver may be one element or may be a plurality of elements, such as a plurality of receivers and transmitters, providing a means for communicating with various other apparatus over a transmission medium. The data processed by the processor 1201 is transmitted over a wireless medium via an antenna, which further receives the data and transmits the data to the processor 1201.

The processor 1201 is responsible for managing the bus and general processing, and may provide various functions including timing, peripheral interfaces, voltage regulation, power management, and other control functions. And memory 1202 may be used to store data used by processor 1201 in performing operations.

Another aspect of the embodiments of the present invention also provides a computer-readable storage medium storing a computer program. The computer program, when executed by a processor, implements the method of setting a dental rotary accessory or the method of manufacturing a dental appliance described in any of the method embodiments described above.

That is, it will be understood by those skilled in the art that all or part of the steps in implementing the methods of the embodiments described above may be implemented by a program stored in a storage medium, where the program includes several instructions for causing a device (which may be a single-chip microcomputer, a chip or the like) or a processor (processor) to perform all or part of the steps in the methods of the embodiments of the invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or other various media capable of storing program codes.

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples of carrying out the invention and that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

Claims

1. A method of setting a dental rotary accessory, comprising:

acquiring a first digital model of a target tooth, wherein the target tooth is a tooth to be corrected by adding a rotary accessory;

after the correction force is applied to the rotary accessory, the correction force is the largest in torque component ratio of twisting around the long axis of the tooth according to the target direction, and a target force application point and a target force application direction are determined on the rotary accessory adding side of the first digital model, wherein the target direction is clockwise or anticlockwise, and the correction force is the force applied to the rotary accessory by the shell-shaped appliance when the shell-shaped appliance is meshed with the rotary accessory arranged on the target tooth;

and determining a target pose of the rotary accessory on the rotary accessory adding side of the first digital model according to the target force application point and the target force application direction so as to set the rotary accessory on the rotary accessory adding side of the first digital model based on the target pose.

2. The method of setting a dental rotational attachment according to claim 1, wherein said determining a target point of application and a target direction of application on the rotational attachment addition side of the first digital model with a maximum ratio of moment components of the orthodontic force to twist around the long axis of the tooth in a target direction after applying the orthodontic force to the rotational attachment comprises:

determining a local coordinate system of the first digitized model;

generating a target model under a local coordinate system of the first digital model, wherein the target model takes a force application point and a force application direction as variables, takes the addition side of the rotating accessory with the force application point positioned on the first digital model as a constraint condition, and takes the maximum ratio of a moment component of the correction force, which is twisted around the long axis of the tooth according to the target direction, to the total moment as a target function;

and determining an optimal solution of the target model to obtain the target force application point and the target force application direction.

3. The method of setting a dental rotational accessory according to claim 2, wherein said determining a local coordinate system of the first digitized model comprises:

determining the tooth long axis direction, the near-far middle direction and the labial-lingual direction of the first digital model;

Determining an impedance center of the first digitized model;

and generating a local coordinate system of the first digital model by taking the determined tooth long axis direction, the determined near-far middle direction and the determined labial lingual direction as three axes of the coordinate system and taking the impedance center as an origin of the coordinate system.

4. A method of setting a dental rotary accessory according to claim 3, wherein in the case where the target direction is counterclockwise, the target model is:

in the case that the target direction is clockwise, the target model is:

5. The method of setting a dental rotational accessory according to claim 3, wherein the determining of the tooth long axis direction, the mesial-distal direction, and the labial-lingual direction of the first digital model comprises:

processing point cloud data contained in the first digital model according to a principal component analysis method to obtain a plurality of orthogonal first feature vectors;

sorting the first feature vectors according to the sequence from the big feature value to the small feature value;

And sequentially determining the first feature vectors positioned in the first order, the second order and the third order in the sorting result as a tooth long axis direction, a near-far middle direction and a labial-lingual direction.

6. The method for setting a tooth rotating attachment according to claim 5, wherein the processing the point cloud data included in the first digitized model according to the principal component analysis method to obtain a plurality of orthogonal first feature vectors includes:

matrixing point cloud data contained in the first digital model to obtain a first matrix;

generating a first covariance matrix of the first matrix;

and carrying out eigenvalue decomposition on the first covariance matrix to obtain a plurality of orthogonal first eigenvectors.

7. The method of setting a dental rotational accessory of claim 6, wherein prior to generating the first covariance matrix of the first matrix, the method further comprises:

performing decentration treatment on the first matrix;

the generating a first covariance matrix of the first matrix includes:

generating the first covariance matrix of the first matrix after decentralization.

8. A method of setting a dental rotational accessory as defined in claim 3, wherein the determining an impedance center of the first digitized model comprises:

Determining a center of gravity of the first digitized model;

taking the center of gravity of the first digital model as the impedance center; or,

and adjusting the gravity center of the first digital model along the long axis direction of the teeth, and taking the adjusted gravity center of the first digital model as the impedance center, wherein the impedance center is closer to the root lowest point of the digital model relative to the gravity center of the first digital model.

9. The method of setting a dental rotational accessory according to claim 8, wherein adjusting the center of gravity of the first digital model along the long axis of the tooth comprises:

along the long axis direction of the tooth, the center of gravity of the first digital model is adjusted by the length of k1 by reference distance, wherein k1 is more than 1/3 and less than 2/5, and the reference distance is the distance between the center of gravity of the first digital model and the lowest point of the root of the tooth of the first digital model.

10. The method of setting a dental rotary accessory according to any one of claims 1 to 9, wherein the rotary accessory includes a connection surface for connection with the target tooth, the method further comprising:

acquiring a second digital model of the rotating accessory;

The determining a target pose of the rotating accessory on the rotating accessory addition side of the first digital model from the target point of application and the target direction of application comprises:

determining the adding position of the rotary accessory according to the target force application point;

determining a stress surface of the rotary accessory according to the target force application direction and the target force application point;

determining a target direction of a connecting surface of the rotary accessory according to the adding position of the rotary accessory, the stress surface of the rotary accessory and a profile surface adding side of the first digital model at the position corresponding to the target force application point;

and positioning the target pose according to the target direction and the adding position of the rotary accessory.

11. The method according to claim 10, wherein determining the target direction of the connection surface of the rotary attachment according to the addition position of the rotary attachment, the force-bearing surface of the rotary attachment, and the rotary attachment addition side at the target point of application of force corresponding to the first digital model includes:

determining the intersection line of the stress surface of the rotary accessory and the contour surface of the first digital model on the adding side of the rotary accessory;

Calculating the tangential direction of the intersection line at the target force application point;

and determining the target direction of the connecting surface of the rotary accessory according to the tangential direction.

12. The method according to any one of claims 1 to 9, wherein the step of determining a target force application point and a target force application direction on the rotational attachment addition side of the first digital model before the step of determining a target force application point and a target force application direction is performed with a maximum torque component ratio of the correction force to twist around the tooth long axis in the target direction after the correction force is applied to the rotational attachment, further comprises:

determining a target area of the target force application point on the rotating accessory addition side of the first digital model according to the size information of the first digital model;

the method for determining the target force application point and the target force application direction on the rotating attachment adding side of the first digital model with the maximum torque component ratio of the correction force twisting around the tooth long axis according to the target direction as the target after the correction force is applied to the rotating attachment comprises the following steps:

and after the correction force is applied to the rotary accessory, the maximum ratio of moment components of the correction force which are twisted around the long axis of the tooth according to the target direction is taken as a target, and the target force application point and the target force application direction are determined in the target area.

13. The method according to claim 12, wherein the size information is a tooth position number, and the determining a target area of the target application point on the rotating attachment adding side of the first digital model according to the size information of the first digital model includes:

determining a first threshold, a second threshold and a third threshold according to the tooth position numbers corresponding to the first digital model, wherein the value range of the first threshold is 2.0-3.0 mm, the value range of the second threshold is 10.0-11.0 mm, and the value range of the third threshold is 2.0-2.5 mm;

determining, on the rotating attachment addition side of the first digitized model, the target area having a distance to the highest point of the incisal edge of the tooth in the direction of the long axis of the tooth greater than the first threshold, a distance to the lowest point of the gum line in the direction of the long axis of the tooth greater than the second threshold, and a distance to the furthest points on both sides of the digitized model in the mesial-distal direction greater than the third threshold.

14. The method according to claim 13, wherein determining, on the rotating attachment addition side of the first digital model, the target area where a distance from a highest point of a tooth incisal edge in a tooth long axis direction is greater than the first threshold, a distance from a lowest point of a gum line in a tooth long axis direction is greater than the second threshold, and a distance from farthest points on both sides of the digital model in a mesial-distal direction is greater than the third threshold, comprises:

Projecting the addition side of the rotary accessory of the first digital model onto a plane formed by the long axis direction and the near-far direction of the tooth to obtain a projection area;

determining rectangular feasible areas with the distance from the tooth cutting edge highest point in the tooth long axis direction being larger than the first threshold, the distance from the tooth cutting edge lowest point in the tooth long axis direction being larger than the second threshold and the distance from the tooth cutting edge lowest point in the mesial-distal direction being larger than the third threshold in the digital model two sides;

pulling up the rectangular feasible region along the direction of the lip-tongue side of the first digital model and the direction of the adding side of the rotary accessory close to the first digital model to obtain a three-dimensional feasible region;

and determining an intersection of the three-dimensional feasible region and the rotating accessory adding side of the first digital model to obtain the target region.

15. The method according to claim 13, wherein determining, on the rotating attachment addition side of the first digital model, the target area where a distance from a highest point of a tooth incisal edge in a tooth long axis direction is greater than the first threshold, a distance from a lowest point of a gum line in a tooth long axis direction is greater than the second threshold, and a distance from farthest points on both sides of the digital model in a mesial-distal direction is greater than the third threshold, comprises:

Determining a first boundary plane below the highest point of the incisal margin of the tooth in the long axis direction of the tooth and at a distance of the first threshold, a second boundary plane above the lowest point of the gum line in the long axis direction of the tooth and at a distance of the second threshold, a third boundary plane at a distance of the third threshold from the mesial-distal most point of the first digital model in the mesial-distal direction, and a fourth boundary plane at a distance of the third threshold from the mesial-distal most point of the first digital model in the mesial-distal direction;

and determining an intersection of a space formed by the joint enclosure of the first boundary plane, the second boundary plane, the third boundary plane and the fourth boundary plane and the rotating accessory adding side of the first digital model to obtain the target area.

16. The method according to any one of claims 1 to 9, characterized in that the determining the target pose of the rotary accessory on the rotary accessory addition side of the first digital model from the target point of application and the target direction of application further comprises:

translating the target force application point away from the target tooth along the labial-lingual direction by a preset distance along a normal vector of an outer contour surface of the rotary accessory addition side of the first digital model at the center, wherein the preset distance is k2, and the thickness of the tooth accessory along the labial-lingual direction is more than 0.25 and less than 0.8;

and determining the target pose of the rotary accessory on the rotary accessory adding side of the digital model according to the translated target force application point and the target force application direction.

17. A method of making a dental appliance, comprising:

the method for setting a dental rotary accessory according to any one of claims 1 to 16, setting a dental accessory on a digital model to obtain a digital orthodontic model;

generating a shell-shaped dental appliance from the digitized orthodontic model.

18. The method of manufacturing an appliance of claim 17, wherein the generating a shell-like appliance from the digital orthodontic model comprises:

manufacturing a male die of the appliance according to the digital orthodontic model;

obtaining a shell-shaped dental appliance comprising a tooth shape by hot-press forming on a male die of the appliance;

a shell dental appliance capable of receiving teeth is cut on the shell dental appliance containing tooth shapes along or adjacent to the gum line.

19. The method of manufacturing a dental appliance of claim 18, wherein the generating a shell dental appliance from the digital orthodontic model comprises:

generating a digital appliance model matched with the digital orthodontic model;

and manufacturing the shell-shaped dental appliance through an additive manufacturing process according to the data information corresponding to the digital appliance model.

20. The tooth correction system is characterized by comprising a plurality of shell-shaped correction devices, wherein the shell-shaped correction devices at least comprise a first shell-shaped correction device, the first shell-shaped correction device at least comprises a tooth accommodating cavity, an accessory accommodating cavity is arranged on the tooth accommodating cavity, and the tooth accommodating cavity is used for accommodating teeth to be rotated;

the dental appliance system further comprises at least one attachment arranged on a target tooth according to the method of arranging a dental rotary attachment of any one of claims 1 to 16, the rotary attachment engaging with an attachment receiving cavity on the first shell appliance when the first shell appliance is worn by a patient to generate an appliance force on the target tooth;

the rotation target of the target teeth is realized by overlapping a plurality of shell-shaped appliances which are worn by a patient in sequence.

21. A tooth attachment setting device, comprising:

the acquisition module is used for acquiring a first digital model of a target tooth, wherein the target tooth is a tooth to be corrected by adding a rotary accessory;

the processing module is used for determining a target force application point and a target force application direction on the rotating accessory adding side of the first digital model by taking the maximum torque component ratio of the correction force which twists around the long axis of the tooth according to the target direction after the correction force is applied to the rotating accessory, wherein the target direction is clockwise or anticlockwise, and the correction force is the force applied to the rotating accessory by the shell-shaped correction device when the shell-shaped correction device is meshed with the rotating accessory arranged on the target tooth;

and the setting module is used for determining a target pose of the rotary accessory on the rotary accessory adding side of the first digital model according to the target application point and the target application direction so as to set the rotary accessory on the rotary accessory adding side of the first digital model based on the target pose.

22. An electronic device, comprising:

At least one processor; the method comprises the steps of,

a memory communicatively coupled to the at least one processor; wherein,

the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of setting a dental rotational accessory as claimed in any one of claims 1 to 16 or to perform the method of manufacturing a dental appliance as claimed in any one of claims 17 to 19.

23. A computer-readable storage medium storing a computer program, wherein the computer program when executed by a processor implements the method of setting a dental rotary accessory according to any one of claims 1 to 16 or implements the method of manufacturing a dental appliance according to any one of claims 17 to 19.