阅读说明：本技术 旋转中心设计检验方法、壳状牙科器械设计及制备方法 (Rotation center design inspection method, shell-shaped dental instrument design and preparation method ) 是由 於路 王心军 姚峻峰 于 2020-04-01 设计创作，主要内容包括：本发明提供旋转中心设计检验方法、壳状牙科器械设计及制备方法,其中,旋转中心设计检验方法包括步骤：单颗数字化牙齿模型的分类、单颗数字化牙齿模型长轴的拟合、数字化牙齿模型阻抗中心的确定、模拟数字化牙齿模型排牙设计、及旋转中心的优化调整,其中,基于施加到数字化牙冠模型上产生的力矩与施加到数字化牙齿矫治器上产生的平衡力矩的比值与排牙设计中的旋转量设计检验旋转中心的预设位置,以实现旋转中心的优化调整。通过对单颗数字化牙齿模型分类、牙齿模型长轴拟合、阻抗中心确定、排牙设计、旋转中心优化调整,使得,设计的牙齿旋转中心和实际矫治过程中的旋转中心基本一致,使牙齿治疗效果符合预期效果,进一步避免了医疗事故的发生。(The invention provides a method for designing and checking a rotation center, a method for designing and manufacturing a shell-shaped dental instrument, wherein the method for designing and checking the rotation center comprises the following steps: the method comprises the steps of classifying single digital tooth models, fitting long shafts of the single digital tooth models, determining impedance centers of the digital tooth models, simulating tooth arrangement design of the digital tooth models and optimizing and adjusting rotation centers, wherein the preset position of the rotation centers is checked based on the ratio of torque generated by applying the digital tooth crown models to balance torque generated by applying the digital tooth appliances and the rotation amount design in the tooth arrangement design, so that the optimized and adjusted rotation centers are realized. Through the classification of a single digital tooth model, the long axis fitting of the tooth model, the determination of the impedance center, the tooth arrangement design and the optimization and adjustment of the rotation center, the designed tooth rotation center is basically consistent with the rotation center in the actual correction process, so that the tooth treatment effect accords with the expected effect, and the occurrence of medical accidents is further avoided.)

1. A design and inspection method for a rotation center based on a digital tooth model is characterized by comprising the following steps:

classification of single digitized tooth models: carrying out classification labeling on the single digital tooth model according to the classification standard of the standard digital tooth model; the single digital tooth model comprises a digital dental crown model and a digital dental root model;

fitting of the long axis of a single digital tooth model: fitting a long axis of the single digitized tooth model based on the classified and labeled single digitized tooth model;

determination of the digital tooth model impedance center: calculating the position of an impedance center point of the digital tooth model based on the point of each point on the single digital tooth model projected to the long axis and the classification labeling information of the digital tooth model;

simulating a digital tooth model tooth arrangement design: simulating a digital tooth model tooth arrangement design based on the initial position and the target correction position of the digital tooth model, and calculating single step movement amount of the digital tooth model, wherein the single step movement amount comprises translation amount and rotation amount of the digital tooth model, and the rotation amount is pose variation generated by the digital tooth model with a rotation center as a rotation point;

optimizing and adjusting the rotation center: respectively superposing impedance central points corresponding to the initial position and the target position of the digital tooth model based on the translation amount, and calculating the rotation amount of the digital tooth model; the preset position of the center of rotation is then verified based on the ratio of the torque applied to the digital crown model to the balancing torque applied to the digital dental appliance and the amount of rotation design.

2. The method of claim 1, wherein the method of classifying the single digitized tooth model comprises:

acquiring a digital dental model: acquiring a digital dental model, wherein the digital dental model comprises a digital dental crown model and a digital dental root model;

segmenting the digital dental model: dividing the digital dental model into single digital tooth models;

classification of single digitized tooth models: and carrying out classification labeling on the single digital tooth model according to the classification standard of the standard digital tooth model.

3. The digital tooth model-based design inspection method for rotation center according to any one of claims 1 or 2, wherein the fitting method for the long axis of the single digital tooth model comprises:

repairing a single digital tooth model: repairing two side surfaces of two adjacent single digital tooth models in the near-far direction after classification and marking;

fitting of the long axis of a single digital tooth model: and performing principal component analysis on the digital tooth model grid to obtain a feature vector corresponding to the maximum feature value as a long axis after fitting.

4. The method as claimed in claim 3, further comprising obtaining a digital alveolar bone model, wherein the intersection of the digital alveolar bone model and the digital tooth model mesh is mapped to a point of the long axis, the apex of the digital alveolar bone model near the digital tooth root model is mapped to a point of the long axis, and the distance between the two points is the height of the digital alveolar bone model along the long axis.

5. The method for designing and verifying a rotation center based on a digital tooth model as claimed in claim 4, wherein the method for determining the impedance center of the digital tooth model specifically comprises:

and calculating the height of the single digital dental crown model along the long axis direction based on the distance between the point of the cusp point of the single digital tooth model mapped to the long axis and the point of the intersection of the digital alveolar bone model and the digital tooth model mesh mapped to the long axis, wherein the point mapped to the long axis by the gum line fitting plane is taken as a starting point, and the position extending to the digital dental crown model in the direction of the digital dental crown model by half of the height is taken as the position of an impedance center.

6. The method for designing and verifying a rotation center based on a digital tooth model as claimed in claim 4, wherein the method for determining the impedance center of the digital tooth model specifically comprises:

based on the distance between the point of the apical point of the single digital tooth model mapped to the long axis and the point of the intersection of the digital alveolar bone model and the digital tooth model mesh mapped to the long axis, the point mapped to the long axis by the gum line fitting plane is taken as a starting point, and the position extending to the direction of the digital tooth root model by half of the distance is taken as the position of the impedance center.

7. The digital tooth model based design verification method of center of rotation according to claim 6, wherein the direction of the long axis is set to be directed to the digital tooth crown model by the digital tooth root model or to be directed to the digital tooth root model by the digital tooth crown model.

8. The method of claim 7, wherein the ratio of the difference between the center of rotation and the center of impedance to the difference between the apex and the center of impedance is set within a predetermined range to determine the accuracy of the design of the single step movement of the digitized tooth model.

9. The method of claim 8, wherein when a ratio of a difference between the center of rotation and the center of impedance to a difference between the apex point and the center of impedance is 0 or more, a ratio of a moment generated by the digital dental crown model to a balance moment generated by the digital dental appliance is 1-Exp [ - (D-C)/(B-C) ], where C is the center of impedance, D is the center of rotation, and B is the apex point.

10. The method of claim 8, wherein a ratio of a moment generated by the digital dental crown model to a balance moment generated by the digital dental appliance is greater than 1 when a ratio of a difference between the center of rotation and the center of impedance to a difference between the apex point and the center of impedance is less than 0.

11. The digital dental model-based design verification method for center of rotation according to any one of claims 8 to 10, wherein a ratio of a moment generated by applying to the digital dental crown model and a balance moment generated by applying to the digital dental appliance based on the amount of change in pose in the analog-digital dental model tooth arrangement design method is subjected to a uniformity test with respect to a ratio of a moment generated by applying to the digital dental crown model and a balance moment generated by applying to the digital dental appliance when the standard digital dental model is moved; if the two ratios are uniform, the adjustment of the rotation center is not needed; if the two ratios are not uniform, the rotation center needs to be adjusted until the two ratios are uniform.

12. The method of claim 11, wherein the pose of the digital dental crown model changes in translation when the ratio of the moment applied to the digital dental crown model generated when the standard digital dental model moves to the balancing moment applied to the digital dental appliance is 1.

13. The digital dental model-based design verification method for center of rotation according to claim 11, wherein the change in the pose of the digital dental crown model is rotation when the ratio of the moment generated by the standard digital dental model when moved to the moment generated by the digital dental crown model and the balance moment generated by the digital dental appliance is 0, or between 0 and 1, or greater than 1.

14. The digital tooth model-based design inspection method for rotation center according to claim 1, wherein the method for obtaining the digital dental model is dental panorama or CBCT.

15. The method for rotational center design inspection based on digital tooth models as claimed in claim 1, wherein the single digital tooth model is classified and labeled by FDI labeling, Parmer tooth position representation or general registration.

16. The method for rotational center design verification based on digital tooth models as claimed in claim 3, wherein there is a boundary between two adjacent digital tooth models, and the repairing method of the digital tooth models comprises:

initial repairing of a segmentation boundary, namely performing initial repairing on the side surface in the near-far-middle direction of two adjacent single digital tooth models so as to perform preliminary fitting on two adjacent surfaces between the two adjacent single digital tooth models, and obtaining an initial repairing grid of the single digital tooth model after the segmentation boundary is completely repaired;

and optimizing and adjusting the initialized patching mesh, and performing optimized adjustment of a preset distance between the vertexes of the initialized patching mesh of two adjacent single digital tooth models by adopting a quadratic programming method so as to prevent two adjacent surfaces between the two adjacent single digital tooth models from colliding with each other.

17. The method of claim 16, wherein the initial step of repairing the segmentation boundary is a digital mesh repairing step using a minimum angle method.

18. A tooth arrangement method based on a digital tooth model is characterized in that: the digital tooth model based design inspection method of any one of claims 1-17 for center of rotation, when qualified, for performing a tooth arrangement design of the digital tooth model.

19. A method of designing a shell-like dental instrument, comprising:

acquiring a digital dental model: acquiring a digital dental model, wherein the digital dental model comprises a digital dental crown model and a digital dental root model;

obtaining a post-dentition digital crown model based on a dentition method based on a digital tooth model as claimed in claim 18;

design of shell-like dental instruments: designing a shell-shaped dental instrument having the digital dental crown model accommodated therein based on the arranged digital dental crown model, wherein the ratio of the moment generated by the shell-shaped dental instrument applied to the digital dental crown model to the balance moment generated by the digital dental crown model applied to the shell-shaped dental instrument is controlled within a predetermined value or range to adjust the pose change of the digital dental model.

20. A method of making a shell-like dental instrument, comprising: the shell-shaped dental instrument designed according to the method for designing a shell-shaped dental instrument of claim 19 is manufactured accordingly, and the specific manufacturing method comprises the following steps: 3D printing is carried out on the digital dental model after the pose change, a solid dental model is prepared, then shell-shaped dental appliances containing tooth shapes are obtained on the solid dental model in a hot press forming mode, and then the shell-shaped dental appliances containing the tooth shapes are obtained by cutting along a gum line or at a position close to the gum line on the shell-shaped dental appliances containing the tooth shapes.

21. A method for manufacturing a shell-shaped dental instrument, wherein the designed shell-shaped dental instrument is manufactured based on the method for designing a shell-shaped dental instrument according to claim 19, and the method comprises the following steps: and printing and preparing the designed shell-shaped dental instrument by adopting a direct 3D printing method.

Technical Field

The invention belongs to the technical field of tooth correction, and particularly relates to a shell-shaped tooth corrector manufacturing technology, in particular to a design inspection method for performing a rotation center based on a digital tooth model, a tooth arrangement method based on the digital tooth model, a shell-shaped dental appliance design method and a shell-shaped dental appliance preparation method.

Background

In the process of designing orthodontic treatment, a single digital tooth model of a patient needs to be moved and arranged in a three-dimensional space, namely, the process of simulating digital tooth arrangement. However, in the current orthodontic treatment of teeth, actual intraoral information of a patient is converted into a digitized tooth three-dimensional model, then the digitized tooth three-dimensional model is segmented to obtain a digitized dental crown model, the surface of the digitized dental crown model is repaired to enable the shape of the repaired digitized dental crown model to be closer to the real tooth shape of the patient, then the digitized dental crown model is subjected to rotational translation operation to gradually change the arrangement mode to a target correction position, and finally a series of tooth correctors are manufactured according to each step of the gradually changed digitized dental crown model.

Because of different data acquisition modes, the digital tooth models are not provided with digital tooth root models, so that the rotation center of the digital tooth models can only be designed on the digital tooth crown models or the repaired digital tooth crown models, parameters of the digital tooth root models need to be simulated and estimated, and the accuracy of the mode has certain deviation, so that the actual corrected position of the teeth is probably not consistent with the expected target correcting position in the actual correcting process, the correcting effect is not ideal for light persons, and the correcting period is prolonged; even in severe cases, the tooth root is removed from the alveolar bone in the process of correcting the tooth, which causes serious medical accidents.

Therefore, the invention provides a corresponding technical scheme aiming at the problem that the selected rotation center is tested in the tooth arrangement designing process to ensure that the rotation center is closer to and better than the real intraoral condition of a patient.

Disclosure of Invention

The invention mainly aims to overcome the defects of the prior art, and provides a design inspection method for performing a rotation center based on a digital tooth model, a tooth arrangement method based on the digital tooth model, a shell-shaped dental appliance design method and a shell-shaped dental appliance preparation method, which solve the problem that the rotation center selected in the digital tooth arrangement process is deviated from the rotation center in the actual correction process.

The technical scheme provided by the invention is as follows:

the invention provides a design and inspection method for a rotation center based on a digital tooth model, which comprises the following steps:

classification of single digitized tooth models: carrying out classification labeling on the single digital tooth model according to the classification standard of the standard digital tooth model; the single digital tooth model comprises a digital dental crown model and a digital dental root model;

fitting of the long axis of a single digital tooth model: fitting a long axis of the single digitized tooth model based on the classified and labeled single digitized tooth model;

determination of the digital tooth model impedance center: calculating the position of an impedance center point of the digital tooth model based on the point of each point on the single digital tooth model projected to the long axis and the classification labeling information of the digital tooth model;

simulating a digital tooth model tooth arrangement design: simulating a digital tooth model tooth arrangement design based on the initial position and the target correction position of the digital tooth model, and calculating single step movement amount of the digital tooth model, wherein the single step movement amount comprises translation amount and rotation amount of the digital tooth model, and the rotation amount is pose variation generated by the digital tooth model with a rotation center as a rotation point;

optimizing and adjusting the rotation center: respectively superposing impedance central points corresponding to the initial position and the target position of the digital tooth model based on the translation amount, and calculating the rotation amount of the digital tooth model; the preset position of the center of rotation is then verified based on the ratio of the torque applied to the digital crown model to the balancing torque applied to the digital dental appliance and the amount of rotation design.

Further preferably, the method for classifying the single digitized tooth model includes:

acquiring a digital dental model: acquiring a digital dental model, wherein the digital dental model comprises a digital dental crown model and a digital dental root model;

segmenting the digital dental model: dividing the digital dental model into single digital tooth models;

classification of single digitized tooth models: and carrying out classification labeling on the single digital tooth model according to the classification standard of the standard digital tooth model.

Further preferably, the method for fitting the long axis of the single digitized tooth model comprises:

repairing a single digital tooth model: repairing two side surfaces of two adjacent single digital tooth models in the near-far direction after classification and marking;

fitting of the long axis of a single digital tooth model: and performing principal component analysis on the digital tooth model grid to obtain a feature vector corresponding to the maximum feature value as a long axis after fitting.

Preferably, the method further comprises the step of obtaining a digital alveolar bone model, wherein the intersection of the digital alveolar bone model and the digital tooth model mesh is mapped to a point of the long axis, a root apex point of the digital alveolar bone model close to the digital tooth root model is mapped to a point of the long axis, and the distance between the two points is the height of the digital alveolar bone model along the direction of the long axis.

Further preferably, the method for determining the digital tooth model impedance center specifically includes:

and calculating the height of the single digital dental crown model along the long axis direction based on the distance between the point of the cusp point of the single digital tooth model mapped to the long axis and the point of the intersection of the digital alveolar bone model and the digital tooth model mesh mapped to the long axis, wherein the point mapped to the long axis by the gum line fitting plane is taken as a starting point, and the position extending to the digital dental crown model in the direction of the digital dental crown model by half of the height is taken as the position of an impedance center.

Further preferably, the method for determining the digital tooth model impedance center specifically includes:

based on the distance between the point of the apical point of the single digital tooth model mapped to the long axis and the point of the intersection of the digital alveolar bone model and the digital tooth model mesh mapped to the long axis, the point mapped to the long axis by the gum line fitting plane is taken as a starting point, and the position extending to the direction of the digital tooth root model by half of the distance is taken as the position of the impedance center.

Further preferably, the direction of the long axis is set to be directed by the digitized tooth root model to the digitized tooth crown model or by the digitized tooth crown model to the digitized tooth root model.

Further preferably, the ratio of the difference from the center of rotation to the center of impedance to the difference from the apex to the center of impedance is set to a predetermined range to determine the accuracy of the single step movement amount design of the digitized tooth model.

Further preferably, when a ratio of a difference between the center of rotation and the center of impedance to a difference between the apex point and the center of digital impedance is equal to or greater than 0, a ratio of a moment generated by the digital crown model to a balance moment generated by the digital appliance is 1-Exp [ - (D-C)/(B-C) ], where C is the center of impedance, D is the center of rotation, and B is the apex point.

Further preferably, when a ratio of a difference between the rotation center and the impedance center to a difference between the apical point and the impedance center is less than 0, a ratio of a moment generated by the digital crown model to a balance moment generated by the digital appliance is greater than 1.

Further preferably, a uniformity check is performed on the ratio of a moment generated by applying the pose change amount to the digital dental crown model and a balance moment generated by applying the pose change amount to the digital dental appliance in the analog-digital dental model arrangement design method, and the ratio of a moment generated by applying the standard digital dental model to the digital dental crown model and a balance moment generated by applying the standard digital dental appliance when the standard digital dental model moves; if the two ratios are uniform, the adjustment of the rotation center is not needed; if the two ratios are not uniform, the rotation center needs to be adjusted until the two ratios are uniform.

Further preferably, the pose change of the digital dental crown model is a translation when the ratio of the moment generated by applying the standard digital dental model to the digital dental crown model when moving to the balance moment generated by applying the standard digital dental model to the digital dental appliance is 1.

Further preferably, when the ratio of the moment generated by the standard digital tooth model when moving and applied to the digital dental crown model to the balance moment generated by the standard digital tooth model when moving and applied to the digital dental appliance is 0, or between 0 and 1, or greater than 1, the pose of the digital dental crown model changes to rotation.

Further preferably, the method for acquiring the digital dental model is dental panorama or CBCT.

Further preferably, the method for classifying and labeling the single digitized tooth model is an FDI labeling method, a parmer tooth position representation method or a general recording method.

Further preferably, a segmentation boundary is arranged between two adjacent segmented single digital tooth models, and the repairing method of the single digital tooth model comprises the following steps:

initial repairing of a segmentation boundary, namely performing initial repairing on the side surface in the near-far-middle direction of two adjacent single digital tooth models so as to perform preliminary fitting on two adjacent surfaces between the two adjacent single digital tooth models, and obtaining an initial repairing grid of the single digital tooth model after the segmentation boundary is completely repaired;

and optimizing and adjusting the initialized patching mesh, and performing optimized adjustment of a preset distance between the vertexes of the initialized patching mesh of two adjacent single digital tooth models by adopting a quadratic programming method so as to prevent two adjacent surfaces between the two adjacent single digital tooth models from colliding with each other.

Further preferably, the initial repairing method of the segmentation boundary is to perform digital mesh repairing on the segmentation boundary by using a minimum angle method.

The invention also provides a tooth arrangement method based on the digital tooth model, which comprises the following steps: and carrying out tooth arrangement design of the digital tooth model after the rotation center is qualified by the design inspection method based on the digital tooth model.

The invention also provides a design method of the shell-shaped dental instrument, which comprises the following steps:

acquiring a digital dental model: acquiring a digital dental model, wherein the digital dental model comprises a digital dental crown model and a digital dental root model;

obtaining a digital dental crown model after tooth arrangement based on the tooth arrangement method based on the digital tooth model;

design of shell-like dental instruments: designing a shell-shaped dental instrument having the digital dental crown model accommodated therein based on the arranged digital dental crown model, wherein the ratio of the moment generated by the shell-shaped dental instrument applied to the digital dental crown model to the balance moment generated by the digital dental crown model applied to the shell-shaped dental instrument is controlled within a predetermined value or range to adjust the pose change of the digital dental model.

The invention also provides a preparation method of the shell-shaped dental instrument, which comprises the following steps: the shell-shaped dental instrument designed by the method is correspondingly prepared based on the shell-shaped dental instrument design method, and the specific preparation method comprises the following steps: 3D printing is carried out on the digital dental model after the pose change, a solid dental model is prepared, then shell-shaped dental appliances containing tooth shapes are obtained on the solid dental model in a hot press forming mode, and then the shell-shaped dental appliances containing the tooth shapes are obtained by cutting along a gum line or at a position close to the gum line on the shell-shaped dental appliances containing the tooth shapes.

The invention also provides a preparation method of the shell-shaped dental instrument, which comprises the following steps: the shell-shaped dental instrument designed by the method is correspondingly prepared based on the shell-shaped dental instrument design method, and the specific preparation method comprises the following steps: and printing and preparing the designed shell-shaped dental instrument by adopting a direct 3D printing method.

According to the design and inspection method for the rotation center based on the digital tooth model, the rotation center designed by the digital tooth model is subjected to design inspection through the steps of classifying a single digital tooth model, fitting a long shaft of the digital tooth model, determining an impedance center, designing a tooth arrangement, optimizing and adjusting the rotation center and the like, and the subsequent tooth arrangement design and the design and preparation of shell-shaped dental appliances are carried out on the rotation center meeting the inspection requirement, so that the consistency of the rotation center designed aiming at the digital tooth model and the actual correction process is ensured, and the tooth treatment effect is ensured to meet the expected target correction effect. Specifically, the position of the impedance center of the individualized tooth of the patient can be accurately determined in the provided determination mode of the impedance center of the digital tooth model, then the analog digital tooth model is used for tooth arrangement design, tooth pose change is generated in the tooth arrangement design, the preset position of the rotation center is adjusted, the rotation center after inspection is adjusted to accord with the more optimal scheme of the tooth arrangement design, the tooth of the patient can be aligned to the target correction position through the subsequently prepared shell-shaped tooth corrector, and the phenomenon that the bone is windowed or cracked is avoided in the tooth moving process is ensured.

Drawings

The foregoing features, technical features, advantages and embodiments are further described in the following detailed description of the preferred embodiments, which is to be read in connection with the accompanying drawings.

FIG. 1 is a flow chart of a method for designing and verifying a center of rotation based on a digitized tooth model according to the present invention;

FIG. 2 is a flowchart of a method for repairing a triangular mesh by a minimum inclusion angle method according to the present invention;

FIG. 3 is a schematic diagram of adding a triangular mesh patch;

FIG. 4 is a schematic diagram of adding two triangular mesh patches;

FIG. 5 is a flowchart illustrating optimization and adjustment of vertices of a mesh to be repaired according to the present invention;

FIG. 6 is a schematic view of a structure of a single digitized tooth model;

FIG. 7 is a flow chart of a digital tooth model based tooth arrangement design provided by the present invention;

FIG. 8 is a flow chart of a shell-like dental instrument design provided by the present invention;

FIG. 9 is a flow chart illustrating the preparation of a shell-shaped dental instrument according to the present invention.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following description will be made with reference to the accompanying drawings. It is obvious that the drawings in the following description are only some examples of the invention, and that for a person skilled in the art, other drawings and embodiments can be derived from them without inventive effort.

For the tooth correction of an orthodontic patient, the method that a doctor needs to align the teeth of the patient is that actual intraoral information of the patient is converted into a digital tooth three-dimensional model, then the digital tooth three-dimensional model is segmented to obtain a digital dental crown model, the surface of the digital dental crown model is repaired to enable the shape of the repaired digital dental crown model to be closer to the real tooth shape of the patient, then the digital dental crown model is rotated and translated to gradually change the arrangement mode to a target correction position, and finally a series of tooth correctors are manufactured according to each step of the digital dental crown model which gradually changes.

Because of different data acquisition modes, the digital tooth models are not provided with digital tooth root models, so that the rotation center of the digital tooth models can only be designed on the digital tooth crown models or the repaired digital tooth crown models, parameters of the digital tooth root models need to be simulated and estimated, and the accuracy of the mode has certain deviation, so that the actual corrected position of the teeth is probably not consistent with the expected target correction position in the actual correction process, the correction effect is not ideal for light persons, and the correction period is prolonged; even in severe cases, the tooth root is removed from the alveolar bone in the process of correcting the tooth, which causes serious medical accidents.

Aiming at the problems, the invention provides a corresponding solution, and the technical scheme provided by the invention solves the problem that the selected rotation center in the digital tooth arrangement process is deviated from the rotation center in the actual correction process. The technical scheme provided by the invention is as follows: