CN108831551B - Computer-aided testing method for orthodontic appliances - Google Patents
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Abstract
本申请的一方面提供了一种计算机辅助牙科正畸矫治器械的检验方法，包括：获取牙颌多网格数字模型，其中，该牙颌多网格数字模型包括多颗牙齿的多网格数字模型、牙周膜多网格数字模型以及牙槽骨多网格数字模型；获取牙科正畸矫治器械的多网格数字模型；将所述牙科正畸矫治器械的多网格数字模型佩戴于所述牙颌多网格数字模型并进行计算，获得包括以下至少之一的计算结果：在所述牙科正畸矫治器械的多网格数字模型、所述牙周膜多网格数字模型以及所述牙槽骨多网格数字模型的作用下，所述多颗牙齿的多网格数字模型所达到的新的布局；以及基于所述计算结果检验所述牙科正畸矫治器械。
An aspect of the present application provides a method for testing a computer-aided dental orthodontic appliance, comprising: acquiring a multi-grid digital model of a tooth and jaw, wherein the multi-grid digital model of the tooth and jaw includes a multi-grid digital model of a plurality of teeth model, periodontal ligament multi-grid digital model and alveolar bone multi-grid digital model; obtain the multi-grid digital model of the orthodontic appliance; wear the multi-grid digital model of the orthodontic appliance on the The multi-grid digital model of the teeth and jaw is calculated and calculated to obtain a calculation result including at least one of the following: the multi-grid digital model of the dental orthodontic appliance, the periodontal ligament multi-grid digital model and the Under the action of the multi-grid digital model of the alveolar bone, a new layout is achieved by the multi-grid digital model of the plurality of teeth; and the orthodontic appliance is checked based on the calculation result.
Description
Technical Field
The present application relates generally to a method of computer-aided inspection of orthodontic appliances.
Background
Due to manufacturing processes, materials, and the like, the dental orthodontic appliances actually manufactured may deviate from the original design, and thus the intended correction purpose may not be achieved.
For example, shell-shaped orthodontic appliances based on polymer materials, which are becoming more popular due to the advantages of beauty, convenience, and convenience for cleaning, are usually manufactured based on a hot-pressing film forming process, but the characteristics of the process determine that the appliances actually manufactured are likely to deviate from the design.
In addition, for some cases, it may be desirable to provide some attachments to the teeth to mate with the shell orthodontic appliance so that the shell orthodontic appliance can apply a predetermined force and/or moment to the dentition as designed. However, there is no established method for guiding the design of accessories, and the accessories are designed mainly according to the experience of a clinician or a technician, which may not fully achieve the expected effect.
In view of the above, there is a need to provide a method of verifying orthodontic appliances to guide and optimize their design.
Disclosure of Invention
One aspect of the present application provides a method for verifying a computer-assisted orthodontic appliance, comprising: acquiring a multi-grid digital model of a jaw, wherein the multi-grid digital model of the jaw comprises a multi-grid digital model of a plurality of teeth, a periodontal ligament multi-grid digital model and an alveolar bone multi-grid digital model; acquiring a multi-grid digital model of the orthodontic appliance; the multi-grid digital model of the orthodontic appliance is worn on the multi-grid digital model of the jaw and the tooth is calculated, and a calculation result comprising at least one of the following is obtained: the new layout of the multi-grid digital models of the teeth is achieved under the action of the multi-grid digital model of the orthodontic appliance, the periodontal ligament multi-grid digital model and the alveolar bone multi-grid digital model; and verifying the orthodontic appliance based on the calculation result.
In some embodiments, the dental multi-mesh digital model can be a multi-mesh digital model of a full dental jaw, or a multi-mesh digital model of a partial dental jaw.
In some embodiments, the dental multi-mesh digital model, the multi-mesh digital model of a plurality of teeth, the multi-mesh digital model of a periodontal ligament, the multi-mesh digital model of an alveolar bone, and the multi-mesh digital model of an orthodontic appliance are finite element models, and the calculating is a finite element analysis.
In some embodiments, the periodontal ligament finite element model encapsulates a root portion of the finite element model of the plurality of teeth, and the alveolar bone finite element model encapsulates the periodontal ligament finite element model.
In some embodiments, the periodontal ligament finite element model and the finite element model of the plurality of teeth have a limited relative degree of freedom of a node at an interface between the two.
In some embodiments, the periodontal ligament finite element model and the finite element models of the plurality of teeth share a node at the interface.
In some embodiments, the periodontal ligament finite element model and the alveolar bone finite element model are constrained in relative degrees of freedom of a node at a contact surface of the two.
In some embodiments, the periodontal ligament finite element model and the alveolar bone finite element model share a node on a contact surface.
In some embodiments, the material of the periodontal ligament finite element model has a Poisson ratio of 0.4 to 0.49, such that the material is substantially incompressible.
In some embodiments, the modulus of elasticity of the material of the alveolar bone finite element model is lower than the actual modulus of elasticity of the alveolar bone.
In some embodiments, after wearing the finite element model of the orthodontic appliance on the finite element model of the jaw, the fluctuation of the interaction force between the two is less than a predetermined value and maintained for a predetermined period of time, and the layout of the plurality of teeth at this time is taken as the new layout.
In some embodiments, the orthodontic appliance is verified by comparing the design layout of the plurality of teeth to the new layout.
In some embodiments, the finite element model of at least one of the plurality of teeth includes an attachment affixed thereto, and the finite element model of the orthodontic appliance is a finite element model of a shell-like orthodontic appliance having a structure thereon that mates with the attachment to enable the finite element model of the shell-like orthodontic appliance to apply a particular force and/or moment to the finite element model of at least one of the plurality of teeth.
Drawings
The above and other features of the present application will be further explained with reference to the accompanying drawings and detailed description thereof. It is appreciated that these drawings depict only several exemplary embodiments in accordance with the disclosure and are therefore not to be considered limiting of its scope. The drawings are not necessarily to scale and wherein like reference numerals refer to like parts, unless otherwise specified.
FIG. 1 is a schematic flow chart of a method of verifying an orthodontic appliance based on computer finite element analysis in one embodiment of the present application;
FIG. 2A schematically illustrates a finite element model of a jaw wearing a finite element model of a shell-like dental appliance;
FIG. 2B is a cross-sectional view of the shell dental appliance and finite element model of the dental jaw shown in FIG. 1; and
fig. 3 is a schematic flow chart of a method for optimizing orthodontic appliances in one embodiment of the present application.
Detailed Description
The following detailed description refers to the accompanying drawings, which form a part of this specification. The exemplary embodiments mentioned in the description and drawings are for illustrative purposes only and are not intended to limit the scope of the present application. Those skilled in the art, having benefit of this disclosure, will appreciate that many other embodiments can be devised which do not depart from the spirit and scope of the present application. It should be understood that the aspects of the present application, as described and illustrated herein, may be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are within the scope of the present application.
One aspect of the present application provides a method for verifying an orthodontic appliance based on computer finite element analysis. The methods of the present application can be used to test a variety of orthodontic appliances, such as traditional bracket-wire appliances and the more popular current invisible appliances. In the following embodiments, a shell-shaped invisible appliance will be described as an example.
Referring to fig. 1, a schematic flow chart of a method 100 for verifying an orthodontic appliance based on computer finite element analysis according to an embodiment of the present application is shown.
In 101, a finite element model of a dental jaw is acquired.
The dental jaw can be either the upper jaw or the lower jaw.
The dental jaw may be a full or partial dental jaw depending on the appliance to be tested.
The finite element models of the jaw may include finite element models of a plurality of teeth of the dentition, a periodontal ligament finite element model, and an alveolar bone finite element model.
In one embodiment, a geometric model of the teeth, periodontal ligament, and alveolar bone of a patient's jaw can be obtained by CT scanning.
In the case of performing correction using a shell-shaped orthodontic appliance (e.g., an invisible appliance), the correction generally needs to be divided into a plurality of successive stages (e.g., 20 to 40 successive stages), each stage corresponding to one shell-shaped orthodontic appliance. However, the jaw of each stage is different, for example, the arrangement of teeth is different in each stage, and the orientation of the cavity of alveolar bone for accommodating the tooth root may be different in each stage. In order to verify a shell-like orthodontic appliance at a certain stage, it is necessary to obtain a geometric model of the jaw at the beginning of the stage.
In one embodiment, the periodontal membrane thickness is assumed to be constant and fixed relative to the root and alveolar bone interface, thus allowing the orientation of the alveolar bone cavity that receives the root to be determined based on the current tooth placement. If the outer contour of the alveolar bone is not changed, a geometric model of the dental jaw can be obtained. If the layout of the teeth at the beginning of each stage is assumed to be consistent with the design, the geometric model of the jaw at the beginning of any stage can be obtained by the method. Methods for obtaining the tooth layout at each stage are well known in the art and will not be described herein.
In a further embodiment, the geometric model of the jaws at the end of a certain stage obtained by analyzing the effect of the shell-like orthodontic appliance in a finite element method can be used as the geometric model of the jaws at the beginning of the next stage.
In one embodiment, the thickness of the periodontal ligament can be set empirically to obtain a geometric model of the periodontal ligament. For example, the thickness of the periodontal ligament may be set to 0.25 to 0.38 mm.
In one embodiment, the material model of the teeth may be an elastic plastic or rigid material model.
If an elastic-plastic material model is adopted, the tooth deformation is small in the correction process, and the strain amount of plastic deformation cannot be achieved, so that the plastic deformation can not be considered. In one example, the modulus of elasticity of the material model of the tooth may be set to a value between 15000 and 25000MPa, such as 20000 MPa. In one example, the Poisson's ratio of the material model of the teeth may be set to a value between 0.15 and 0.4, such as 0.3.
The properties of periodontal ligament mainly include almost incompressible. In one embodiment, the modulus of elasticity of the material model of the periodontal ligament can be set to a value between 0.05 and 70MPa, such as 0.68 MPa. When the poisson's ratio is 0.5, the material is incompressible. In one example, the Poisson's ratio of the material model of the periodontal ligament can be set to a value between 0.4 and 0.49, such as 0.45, making it almost incompressible.
In one embodiment, the material model of the alveolar bone may employ an elastic-plastic or rigid material model, and plastic deformation may not be considered, similar to the case of teeth.
In one example, the modulus of elasticity of the material model of the alveolar bone may be set to a value between 12000 and 15000MPa, such as 13700 MPa. In one example, the Poisson's ratio of the material model of the alveolar bone may be set to a value between 0.2 and 0.4, such as 0.3.
Alveolar bone is subject to osteoclastogenesis during actual orthodontics. Therefore, when one correction stage is completed, the shell-shaped orthodontic appliance worn on the dentition is less stressed, and accordingly, the shell-shaped orthodontic appliance is less deformed. Since the finite element model of the alveolar bone in one embodiment of the present application does not include the characteristic of osteoclastogenesis, when the finite element model of the shell-shaped orthodontic appliance is worn on the finite element model of the jaw and reaches a balance, the stress of the finite element model of the shell-shaped orthodontic appliance is large, and accordingly, the deformation of the finite element model of the shell-shaped orthodontic appliance is large, that is, the tooth layout of the finite element model of the jaw is different from the tooth layout that the shell-shaped orthodontic appliance can actually reach at this time.
In one example, to compensate to some extent for the deviation due to the fact that the finite element model of alveolar bone does not have osteoclastic properties, the elastic modulus of the material may be reduced accordingly to be lower than the actual elastic modulus of alveolar bone.
In one embodiment, to simplify the calculation, the relative freedom of the contact surface of the finite element model of the tooth and the finite element model of the periodontal ligament can be constrained, i.e. the contact surface of the tooth root and the periodontal ligament is set not to be displaced relatively. In one embodiment, the contact surfaces of the finite element model of the tooth and the finite element model of the periodontal ligament may be made to share a node, thereby limiting the relative degrees of freedom of the two contact surfaces.
Similarly, in one embodiment, to simplify the calculations, the relative degrees of freedom of the interface of the alveolar bone finite element model and the periodontal ligament finite element model can be constrained, i.e., the interface of the alveolar bone and the periodontal ligament is set to be free from relative displacement. In one embodiment, the contact surfaces of the bone finite element model and the periodontal ligament finite element model can share a node, thereby limiting the relative freedom of the contact surfaces.
Based on the geometric models, the material models and the constraint conditions of the teeth, the periodontal ligament and the alveolar bone, the finite element model of the jaw can be obtained.
In 103, a finite element model of the orthodontic appliance is obtained.
At present, the hot pressing film forming process is a relatively common method for manufacturing shell-shaped dental instruments. In the method, a polymer membrane is subjected to hot-pressing film forming on a dental model to obtain a corresponding female die, and then the redundant part of the female die is cut off to obtain the shell-shaped dental appliance.
The tooth layout of the cast may substantially correspond to the target tooth layout for one stage of correction. In one embodiment, a digital model of the dental cast may be obtained and then the dental cast may be fabricated using the digital model control apparatus. Thus, in one embodiment, a digital model of the corresponding negative mold may be generated based on the digital model of the dental cast and a finite element model of the shell-like orthodontic appliance may be generated based thereon.
Since the shell-shaped orthodontic appliance manufactured based on the hot pressing film forming method may have the situations of uneven thickness distribution and inconsistency of the actual shape with the designed shape, in order to make the analysis closer to the actual situation, in one embodiment, finite element simulation may be performed on the manufacturing process of the shell-shaped orthodontic appliance to obtain a finite element model of the shell-shaped orthodontic appliance closer to the actual situation. The applicant of the present application filed 201610304667.X, application serial No. 3, 201610304301.2, filed 2016, 5, 10, discloses a method for finite element simulation of a shell-shaped dental instrument manufacturing process, wherein the method is based on a hot-press forming technique for verifying a dental mouthpiece manufacturing process, and the method is based on a hot-press forming technique for verifying a dental mouthpiece manufacturing process.
At 105, a finite element model of the orthodontic appliance is worn on the finite element model of the jaw and a finite element analysis is performed.
In one embodiment, the finite element model of the orthodontic appliance is worn on the finite element model of the jaw, that is, the finite element model of the jaw and the finite element model of the orthodontic appliance are constrained and combined, and the problem of rigid-flexible coupling dynamic contact as a nonlinear structure can be solved.
In one embodiment, the degrees of freedom of the finite element models of the teeth may be restricted first in the finite element models of the jaws, and the restrictions on the degrees of freedom of the finite element models of the teeth may be released after the finite element model of the orthodontic appliance is worn on the finite element models of the jaws. This simplifies the calculation of wearing a finite element model of an orthodontic appliance on a finite element model of the jaw.
Taking the shell-shaped orthodontic appliance as an example, in one embodiment, three points which are not on the same straight line can be randomly selected on the position of the finite element model of the shell-shaped orthodontic appliance corresponding to each tooth, and the three points are set to be in rigid connection, namely, six degrees of freedom of each connected node are completely synchronous and have no relative deformation with each other. This may make the calculation of the finite element analysis more stable.
Then, one can randomly select a point (which is not present in the penetrating interference of the tooth) on the site of the finite element model of the shell-like orthodontic appliance corresponding to each tooth, apply full constraint of six degrees of freedom to the points, or define only the rotational degrees of freedom of the points in all directions. This may also make the calculation of the finite element analysis more stable.
The mutual position of the inner surface of the finite element model of the shell-like orthodontic appliance and the outer surface of the finite element model of the tooth may then be defined in a manner of initial conditions, for example, by performing a preliminary form fit using a best fit alignment algorithm, or by moving the inner surface of the finite element model of the shell-like orthodontic appliance to the outer surface of the finite element model of the tooth by means of a finite element preprocessing tool.
The finite element model of the shell orthodontic appliance is then subjected to a constant load in a direction (e.g., normal to the outer surface of the dentition) using an explicit algorithm. After establishing the initial contact, the previously applied load is slowly unloaded using an explicit algorithm.
After contact establishment is completed by using an explicit algorithm, releasing all contact constraints on the shell-shaped orthodontic appliance, and then performing stress redistribution calculation by using an implicit algorithm to eliminate unreal stress concentration caused by the constraints, so as to obtain a finite element model of the shell-shaped orthodontic appliance worn on the dental jaw, wherein the finite element model includes but is not limited to the geometric form and the stress distribution of the shell-shaped orthodontic appliance worn on the dentition.
At this time, the limitation of the degree of freedom of the finite element model of the tooth can be released to perform the finite element analysis of the movement of the tooth under the action of the shell-shaped orthodontic appliance.
In one embodiment, the contact between teeth and shell orthodontic appliances may be provided as non-adhesive, slidable, frictional, non-penetrating contact types/characteristics.
In one embodiment, the contact between the tooth and the periodontal ligament, and between the periodontal ligament and the alveolar bone, may be provided as a adhesively bonded, non-slidable, non-releasable, non-penetrating contact type/feature. Further, in one embodiment, the tooth may be made to share a node with the periodontal ligament, which shares a node with the alveolar bone.
In one embodiment, a finite element node can be arbitrarily selected on the finite element model of the alveolar bone at a position not in contact with the finite element model of the periodontal ligament, and full constraint of six degrees of freedom (the alveolar bone can be deformed but is not displaced as a whole) is applied to the node as one of boundary conditions of finite element analysis on tooth movement.
In one embodiment, a finite element node can be arbitrarily selected on the finite element model of the tooth at a position without contact with the shell-shaped orthodontic appliance, and the node is rigidly connected with the origin of the local coordinate system of the tooth, so that the local coordinate system of the tooth moves along with the movement of the tooth.
In one embodiment, a threshold may be set when the force fluctuations across the finite element model of the shell orthodontic appliance are less than the threshold and held for a period of time that is considered to be equilibrium. The new layout of the teeth at this time can be used as the orthodontic effect which can be achieved by the shell-shaped orthodontic appliance, namely, the layout of the teeth after the shell-shaped orthodontic appliance is fully worn.
Referring to fig. 2A, a geometric model of a dental jaw 201 is schematically illustrated with a geometric model of a shell-like orthodontic appliance 205 worn thereon. Wherein the geometric model 201 of the dental jaw comprises attachments 203 a-203 d fixedly arranged on some of the teeth.
Referring again to fig. 2B, a cross-sectional view at a-a of the geometric model 201 of the dental jaw and the geometric model of the shell-like orthodontic appliance 205 of fig. 2A is shown.
The geometric model 201 of the dental jaw includes a geometric model 2011 of the tooth, a geometric model 2013 of the periodontal ligament covering the root portion of the geometric model 2011 of the tooth, and a geometric model 2015 of the alveolar bone covering the geometric model 2013 of the periodontal ligament.
The geometric model 205 of the shell-shaped orthodontic appliance is provided with an external protrusion 2051 to cooperate with the geometric model 203c of the attachment provided on the geometric model 2011 of the tooth to enhance the mutual fixation between the geometric model 205 of the shell-shaped orthodontic appliance and the tooth. It is understood that the protruding structure 2051 may be replaced by a hollowed-out structure.
In 107, the orthodontic appliance is verified based on the finite element analysis results.
In one embodiment, the new arrangement of teeth obtained in 105 can be compared to a design-expected arrangement of teeth, and if the difference (including distance and angle) between the two meets a predetermined requirement, the orthodontic appliance is qualified, otherwise, the orthodontic appliance is not qualified.
In one embodiment, a tooth position deviation threshold and a lower match rate limit may be preset. When the new tooth layout is compared with the designed tooth layout, if the range of the form matching area smaller than the tooth position deviation threshold value is larger than the lower limit of the matching rate, the orthodontic appliance is qualified.
In one embodiment, the tooth position deviation threshold may be set to 0.1mm and the lower match rate limit may be set to 90%.
In one embodiment, the orthodontic appliance can include a shell-like orthodontic appliance and an attachment secured to a tooth. In some cases, in order to make a tooth act as an anchorage, or to apply a specific force to the tooth (such as a force to lower or raise the tooth), it is necessary to fixedly provide an attachment to the tooth, and to provide a corresponding structure (such as a hollowed structure or an outwardly protruding structure) on the shell orthodontic appliance to cooperate with the attachment so that the shell orthodontic appliance can apply a desired force to the tooth.
The application discloses a computer finite element analysis-based method for inspecting orthodontic appliances, which can inspect the orthodontic effect of the appliances at the design stage before the appliances are manufactured, so that the design of the appliances is guided, the design is improved, the orthodontic efficiency is improved, and the economic benefit is improved.
Referring to fig. 3, a schematic flow chart of a method 300 for optimizing an orthodontic appliance in one embodiment of the present application is shown.
In 301, the quality of the orthodontic appliance is verified, where the computer finite element analysis based orthodontic appliance verification method of the present application may be employed.
And if the test result is qualified, jumping to 303 and ending the process.
If the test result is "not qualified", the process jumps to 305, and the design of the orthodontic appliance is optimized based on the result of the finite element analysis.
For the shell-shaped orthodontic appliance, the manufacturing parameters can be optimized, and the manufacturing parameters comprise process parameters (such as hot-pressing film forming process parameters), materials (different materials are selected to obtain different mechanical and mechanical properties), thicknesses (such as membranes with different thicknesses are selected), and geometric forms of the male die (such as the undercut of the male die can be modified to change the matching of the shell-shaped orthodontic appliance and the dentition, the dental arch curve of the male die can be modified (such as expansion compensation) to change the matching of the shell-shaped orthodontic appliance and the dentition, and the matching structure of the shell-shaped dental appliance and accessories can be modified to change the matching of the shell-shaped dental appliance and the accessories fixed on the dentition).
In some embodiments, attachments may be provided on the teeth that mate with corresponding structures on the shell orthodontic appliance so that the shell orthodontic appliance can apply the forces to the dentition as intended. Design optimization of orthodontic appliances may also include optimization of attachment design. In some embodiments, accessory design can be optimized by changing the geometry, dimensions, and mounting orientation of the accessory.
In one embodiment, a finite element analysis may be performed on the fabrication process of the shell-shaped orthodontic appliance based on the design of the optimized orthodontic appliance to obtain a finite element model of the optimized shell-shaped orthodontic appliance.
And jumping to 301, the optimized orthodontic appliance is checked. And circulating the steps until the qualified orthodontic appliance is obtained.
The finite element analysis in the present application may be implemented using any suitable finite element analysis software. Currently, the more popular finite element analysis software includes ANSYS, NASTRAN, CATIA, FEPG, SciFEA, JiFEX, KMAS, FELAC, DYNAFORM, LS-DYNA, ABAQUS, HyperWorks, etc.
Although the above embodiments have described the Method for inspecting an orthodontic appliance according to the present invention by taking Finite element analysis as an example, it is understood that the Finite element Method is only one of numerical calculation methods of a multi-mesh model, and may be implemented by sampling a Finite Volume Method (Finite Volume Method), a Finite Difference Method (Finite Difference Method), a region decomposition Method, a Finite point Method, a boundary element Method, and the like, in addition to the Finite element Method.
While various aspects and embodiments of the disclosure are disclosed herein, other aspects and embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification. The various aspects and embodiments disclosed herein are for purposes of illustration only and are not intended to be limiting. The scope and spirit of the application are to be determined only by the claims appended hereto.
Likewise, the various diagrams may illustrate an exemplary architecture or other configuration of the disclosed methods and systems that is useful for understanding the features and functionality that may be included in the disclosed methods and systems. The claimed subject matter is not limited to the exemplary architectures or configurations shown, but rather, the desired features can be implemented using a variety of alternative architectures and configurations. In addition, to the extent that flow diagrams, functional descriptions, and method claims do not follow, the order in which the blocks are presented should not be limited to the various embodiments which perform the recited functions in the same order, unless the context clearly dictates otherwise.
Unless otherwise expressly stated, the terms and phrases used herein, and variations thereof, are to be construed as open-ended as opposed to limiting. In some instances, the presence of an extensible term or phrases such as "one or more," "at least," "but not limited to," or other similar terms should not be construed as intended or required to imply a narrowing in instances where such extensible terms may not be present.
Claims (9)
1. A method of computer-assisted verification of orthodontic appliances, comprising:
acquiring a multi-grid digital model of a jaw, wherein the multi-grid digital model of the jaw comprises a multi-grid digital model of a plurality of teeth, a periodontal ligament multi-grid digital model and an alveolar bone multi-grid digital model;
acquiring a multi-grid digital model of the orthodontic appliance;
the multi-grid digital model of the orthodontic appliance is worn on the multi-grid digital model of the jaw and the tooth is calculated, and a calculation result comprising at least one of the following is obtained: the new layout of the multi-grid digital models of the teeth is achieved under the action of the multi-grid digital model of the orthodontic appliance, the periodontal ligament multi-grid digital model and the alveolar bone multi-grid digital model; and
verifying the orthodontic appliance based on the calculation,
the dental jaw multi-grid digital model, the multi-grid digital models of a plurality of teeth, the periodontal ligament multi-grid digital model, the alveolar bone multi-grid digital model and the multi-grid digital model of the orthodontic appliance are finite element models, the calculation is finite element analysis, the Poisson ratio of a material of the periodontal ligament finite element model is 0.4-0.49, and the elastic modulus of the material of the alveolar bone finite element model is lower than the actual elastic modulus of the alveolar bone.
2. The method of computer-aided orthodontic appliance examination of claim 1, wherein the periodontal ligament finite element model wraps a root portion of the finite element model of the plurality of teeth, and the alveolar bone finite element model wraps the periodontal ligament finite element model.
3. The method of computer-assisted orthodontic appliance examination of claim 2 wherein the periodontal ligament finite element model and the finite element model of the plurality of teeth have a limited relative degree of freedom of a node at the interface.
4. The method of computer-assisted orthodontic appliance inspection of claim 3 wherein the periodontal ligament finite element model and the finite element models of the plurality of teeth share a node at the interface.
5. The method of computer-assisted orthodontic appliance examination of claim 2, wherein the periodontal ligament finite element model and the alveolar bone finite element model have a limited relative degree of freedom of a node at a contact surface therebetween.
6. The method of computer-assisted orthodontic appliance examination of claim 5, wherein the periodontal ligament finite element model and the alveolar bone finite element model share a node on a contact surface.
7. The computer-aided method of inspecting an orthodontic appliance according to claim 1, wherein after the finite element model of the orthodontic appliance is worn on the finite element model of the jaw, the fluctuation of the interaction force between the finite element model and the jaw is less than a predetermined value and is maintained for a predetermined period of time, and the layout of the plurality of teeth at this time is taken as the new layout.
8. The method of computer-aided orthodontic appliance inspection of claim 1 wherein the orthodontic appliance is inspected by comparing the design layout of the plurality of teeth to the new layout.
9. The method of computer-aided orthodontic appliance of claim 1 wherein the finite element model of at least one of the plurality of teeth includes an attachment affixed thereto and the finite element model of the orthodontic appliance is a finite element model of a shell-like orthodontic appliance having a structure thereon that mates with the attachment such that the finite element model of the shell-like orthodontic appliance is capable of applying a particular force and/or moment to the finite element model of the at least one of the plurality of teeth.
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| CN110298072A (en) * | 2019-05-17 | 2019-10-01 | 太原理工大学 | The design method of human body posture corrective belt based on finite element analysis |
| CN110559093B (en) * | 2019-09-20 | 2022-07-01 | 正雅齿科科技(上海)有限公司 | Preparation method and preparation device of dental instrument and electronic equipment |
| CN111046451B (en) * | 2019-12-06 | 2023-06-13 | 正雅齿科科技(上海)有限公司 | Periodontal ligament stress analysis method and device |
| CN111265316B (en) * | 2019-12-06 | 2021-12-14 | 正雅齿科科技(上海)有限公司 | Tooth model stress analysis method and device for simulating wearing of orthodontic appliance |
| CN111274721B (en) * | 2019-12-06 | 2023-02-28 | 正雅齿科科技(上海)有限公司 | Dental instrument design method and device |
| CN111274653B (en) * | 2019-12-06 | 2023-03-24 | 正雅齿科科技(上海)有限公司 | Design inspection method and device for dental instrument |
| CN111027111B (en) * | 2019-12-06 | 2023-06-13 | 正雅齿科科技(上海)有限公司 | Digital periodontal ligament model generation method and device |
| CN113134974A (en) * | 2020-01-20 | 2021-07-20 | 上海阔鸿信息科技有限公司 | Method for manufacturing shell-shaped dental instrument |
| CN114861507B (en) * | 2022-06-20 | 2024-11-29 | 淮阴工学院 | Modeling and finite element method for orthodontic appliance manufacturing process of dental film |
| CN115410714A (en) * | 2022-09-16 | 2022-11-29 | 罗慕科技(北京)有限公司 | Orthodontic effect prediction method and optimal orthodontic scheme determination method |
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| US6471511B1 (en) * | 1997-06-20 | 2002-10-29 | Align Technology, Inc. | Defining tooth-moving appliances computationally |
| US5975893A (en) * | 1997-06-20 | 1999-11-02 | Align Technology, Inc. | Method and system for incrementally moving teeth |
| US7987099B2 (en) * | 2004-02-27 | 2011-07-26 | Align Technology, Inc. | Dental data mining |
| CN101589968A (en) * | 2009-06-17 | 2009-12-02 | 徐宝华 | Make the method for orthodontic bracket |
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