CN113134969B - Methods for manufacturing shell-shaped dental instruments - Google Patents
Methods for manufacturing shell-shaped dental instrumentsInfo
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- CN113134969B CN113134969B CN202010067433.4A CN202010067433A CN113134969B CN 113134969 B CN113134969 B CN 113134969B CN 202010067433 A CN202010067433 A CN 202010067433A CN 113134969 B CN113134969 B CN 113134969B
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
- A61C7/00—Orthodontics, i.e. obtaining or maintaining the desired position of teeth, e.g. by straightening, evening, regulating, separating, or by correcting malocclusions
- A61C7/08—Mouthpiece-type retainers or positioners, e.g. for both the lower and upper arch
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
- B29C64/10—Processes of additive manufacturing
- B29C64/106—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
- B29C64/112—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material using individual droplets, e.g. from jetting heads
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
- B29C64/30—Auxiliary operations or equipment
- B29C64/386—Data acquisition or data processing for additive manufacturing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
- B29C64/30—Auxiliary operations or equipment
- B29C64/386—Data acquisition or data processing for additive manufacturing
- B29C64/393—Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y10/00—Processes of additive manufacturing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y50/00—Data acquisition or data processing for additive manufacturing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y50/00—Data acquisition or data processing for additive manufacturing
- B33Y50/02—Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Optics & Photonics (AREA)
- Health & Medical Sciences (AREA)
- Oral & Maxillofacial Surgery (AREA)
- Dentistry (AREA)
- Epidemiology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Dental Tools And Instruments Or Auxiliary Dental Instruments (AREA)
Abstract
本申请的一方面提供了一种壳状牙科器械制作方法，包括：获取牙齿的三维数字模型；基于所述牙齿的三维数字模型产生壳状牙科器械的非参数化三维数字模型；基于所述壳状牙科器械的非参数化三维数字模型产生壳状牙科器械的参数化三维数字模型；修改所述壳状牙科器械的参数化三维数字模型的至少一个几何参数；基于所述经修改的壳状牙科器械的参数化三维数字模型产生3D打印数字文件；以及利用所述3D打印数字文件控制3D打印设备制作壳状牙科器械。
One aspect of this application provides a method for manufacturing a shell-shaped dental instrument, comprising: acquiring a three-dimensional digital model of a tooth; generating a non-parametric three-dimensional digital model of the shell-shaped dental instrument based on the three-dimensional digital model of the tooth; generating a parametric three-dimensional digital model of the shell-shaped dental instrument based on the non-parametric three-dimensional digital model of the shell-shaped dental instrument; modifying at least one geometric parameter of the parametric three-dimensional digital model of the shell-shaped dental instrument; generating a 3D printing digital file based on the modified parametric three-dimensional digital model of the shell-shaped dental instrument; and controlling a 3D printing device to manufacture the shell-shaped dental instrument using the 3D printing digital file.
Description
Technical Field
The present application relates generally to shell dental instrument manufacturing methods, and more particularly to shell dental instrument manufacturing methods based on 3D printing techniques.
Background
Shell-shaped dental appliances (e.g., shell appliances, shell holders, etc.) based on polymeric materials are becoming increasingly popular due to their aesthetic, convenience, and cleaning benefits.
The traditional method of manufacturing shell dental instruments is based on a hot press film forming process, however, limitations of the process itself place limitations on aspects of the shell dental instruments.
In view of the above, there is a need to develop a new method of manufacturing shell dental instruments that is free of the limitations of conventional processes on the shell dental instruments.
Disclosure of Invention
An aspect of the present application provides a method of manufacturing a shell dental appliance comprising obtaining a three-dimensional digital model of a tooth, generating a non-parametric three-dimensional digital model of the shell dental appliance based on the three-dimensional digital model of the tooth, generating a parametric three-dimensional digital model of the shell dental appliance based on the non-parametric three-dimensional digital model of the shell dental appliance, modifying at least one geometric parameter of the parametric three-dimensional digital model of the shell dental appliance, generating a 3D printed digital file based on the modified parametric three-dimensional digital model of the shell dental appliance, and controlling a 3D printing device to manufacture the shell dental appliance using the 3D printed digital file.
In some embodiments, the shell dental appliance can be a shell appliance for repositioning teeth from a first configuration to a second configuration.
In some embodiments, the non-parametric three-dimensional digital model expresses geometry in geometric data only, and the parametric three-dimensional digital model expresses geometry in both geometric data and parametric descriptions.
In some embodiments, the geometric parameter comprises thickness.
In some embodiments, the parametric three-dimensional digital model may be a parametric shell-unit model.
In some embodiments, the method of manufacturing a shell dental instrument may further comprise verifying a parameterized three-dimensional digital model of the shell dental instrument, wherein modifying the parameterized three-dimensional digital model of the shell dental instrument is based on results of the verifying.
In some embodiments, the verification may be based on finite element analysis.
In some embodiments, the non-parametric three-dimensional digital model may be an STL model.
Drawings
The above and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments of the present disclosure and are not therefore to be considered limiting of its scope, the present disclosure will be described with additional specificity and detail through use of the accompanying drawings.
FIG. 1 is a schematic flow chart of a method of manufacturing a shell dental instrument in one embodiment of the application;
FIG. 1A is a schematic flow chart of generating a parameterized three-dimensional digital model of a shell dental implement based on a three-dimensional digital model of a tooth in one embodiment of the application;
FIG. 2 schematically illustrates a simplified numerical model in one embodiment of the application;
FIG. 3 schematically illustrates the relationship between force value and cross-sectional area of a shell appliance in one embodiment of the application;
FIG. 4 schematically illustrates a cross-sectional profile of a shell-like appliance in one embodiment of the application;
FIG. 5 schematically illustrates the relationship between force value and wrap area for a shell appliance in one embodiment of the application;
FIG. 6A schematically illustrates a cross-sectional profile of a shell-like appliance with an oversized wrap area;
FIG. 6B schematically illustrates a cross-sectional profile of a shell-like appliance with reduced wrap area in one embodiment of the present application;
Fig. 7 schematically illustrates a cross-sectional profile of a shell-like appliance capable of opening a bite in one embodiment of the present application.
Detailed Description
In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, like reference numerals generally refer to like elements unless the context indicates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter described herein. It should be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, could be arranged, substituted, and combined in a wide variety of different configurations, all of which are explicitly contemplated and make part of this disclosure.
In order to overcome the limitations of the traditional hot-press film forming technology on all aspects of the shell-shaped dental instrument, the inventor of the application develops a manufacturing method of the shell-shaped dental instrument based on the 3D printing technology through a great deal of work.
The shell dental appliance is a unitary shell that defines a cavity for receiving a tooth, the geometry of the cavity substantially matching a particular layout of the tooth.
In one embodiment, the shell dental appliance can be a shell appliance having a geometry that enables it to reposition teeth from a first configuration to a second configuration using the spring force created by the deformation. In yet another embodiment, the shell dental appliance may be a shell retainer for retaining teeth in a current configuration.
Referring to fig. 1, a schematic flow chart of a method 100 for manufacturing a shell dental instrument based on 3D printing technology in one embodiment of the application is shown.
At 101, a parameterized three-dimensional digital model of the shell dental implement is generated based on the three-dimensional digital model of the tooth.
In one embodiment, the three-dimensional digital model of the tooth is a non-parametric three-dimensional digital model.
The non-parametric three-dimensional digital model expresses geometry only in geometric data, without parametric description of geometric features. For example, a non-parametric three-dimensional digital model typically expresses geometric shapes in terms of geometric data such as vertices, patches, normal vectors, etc., and, for example, STL (Stereolithography)'s document, the geometric data includes the vertices of each triangular patch, and the coordinate values of all the vertices in the world coordinate system.
The parameterized three-dimensional digital model expresses geometry in both geometric data and parameterized descriptions. The geometric parameters in the parameterized three-dimensional digital model may include variable parameters and invariant parameters. Examples of geometric parameters include thickness, curvature, radius, positional relationship, and the like.
Modification of the geometry of a non-parametric three-dimensional digital model can only be achieved by directly modifying the geometry data, and the geometrical features (e.g., thickness, curvature, radius, etc.) cannot be intuitively and accurately controlled, which makes targeted modification of the geometry of the three-dimensional digital model (e.g., obtaining a specific thickness, curvature, radius, etc.) very difficult. In contrast, since the parameterized three-dimensional digital model includes not only geometric data but also parameters describing geometric features, modification of the parameterized three-dimensional digital model can intuitively and accurately obtain the target geometric form by modifying the corresponding parameters, which makes control of the geometric form of the three-dimensional digital model very convenient, intuitive and accurate.
Referring to FIG. 1A, a schematic flow chart of one embodiment 101 of the present application is shown.
At 1011, a three-dimensional digital model of the tooth is acquired.
In one embodiment, the shell dental appliance can be a shell appliance and the three-dimensional digital model of the teeth can be a three-dimensional digital model of the dentition (e.g., maxillary dentition or mandibular dentition) in a target layout corresponding to the appliance step.
In yet another embodiment, the shell dental appliance may be a shell retainer and the three-dimensional digital model of the tooth may be a three-dimensional digital model of the dentition (e.g., maxillary dentition or mandibular dentition) in a desired layout.
Dental orthodontic appliances using shell appliances typically require dividing the appliance into a plurality of sequential appliance steps (e.g., 20-40 sequential appliance steps), one shell appliance for each appliance step for repositioning teeth from an initial placement for that appliance step to a target placement for that appliance step.
In one embodiment, shell appliances may be made based on a three-dimensional digital model of the dentition under a target layout corresponding to the appliance steps.
In one embodiment, a series of successive target layouts of orthodontic steps may be generated based on a three-dimensional digital model of the dentition under an original layout prior to orthodontic treatment.
In one embodiment, a three-dimensional digital model of the dentition in the original layout may be obtained by directly scanning the patient's dentition. In yet another embodiment, a three-dimensional digital model of the dentition in the original layout may be obtained by scanning a solid model of the patient's dentition, such as a plaster model. In yet another embodiment, a three-dimensional digital model of the dentition in the original layout may be obtained by scanning the bite model of the patient's dentition.
In one embodiment, after a three-dimensional digital model of the dentition in the original layout is obtained, it may be segmented such that the teeth in the three-dimensional digital model are independent of each other, thereby enabling each tooth to be moved individually.
In one embodiment, a series of successive intermediate layouts, i.e., a series of successive target layouts of the correction steps, can be generated based on the original layout and the desired layout.
In one embodiment, a three-dimensional digital model of the dentition in the desired layout may be obtained based on the three-dimensional digital model of the dentition in the segmented original layout. In one embodiment, the three-dimensional digital model of the dentition under the segmented original layout may be manually manipulated to move each tooth to a desired position to obtain a three-dimensional digital model of the dentition under the desired layout. In yet another embodiment, a computer may be utilized to automatically move each tooth to a desired position based on the three-dimensional digital model of the dentition in the original segmented layout, resulting in a three-dimensional digital model of the dentition in the desired layout.
In one embodiment, after the original and desired layouts are obtained, interpolation calculations can be performed based on both to obtain a series of successive target layouts of the correction steps.
In yet another embodiment, a three-dimensional digital model of the dentition under the original layout may be manually manipulated to directly obtain a target layout of a series of successive correction steps.
In yet another embodiment, a computer can be used to automatically generate a series of successive target layouts of the appliance steps based on a three-dimensional digital model of the dentition under the original layout using a particular method (e.g., a spatial search method).
A more general format of the three-dimensional digital model of teeth is an STL model (or STL file), and each embodiment of the present application will be described below by taking the three-dimensional digital model of teeth in the STL format as an example. The STL file format is an interface protocol established by 3D SYSTEMS corporation in 1988, and is a three-dimensional graphics file format serving rapid prototyping techniques. The STL file is composed of a plurality of triangle patch definitions, each triangle patch definition including three-dimensional coordinates of each vertex of the triangle and a normal vector of the triangle patch. The STL model is essentially a three-dimensional body surrounded by a closed surface, which has no thickness definition.
In 1013, a non-parametric three-dimensional digital model of the shell dental implement is generated based on the three-dimensional digital model of the tooth.
In one embodiment, the three-dimensional digital model of the tooth may be a three-dimensional digital model of the dental jaw that retains only the crown portion after the gingival part is removed.
In one embodiment, the three-dimensional digital model of the tooth may be subjected to a wrapping operation to produce a first three-dimensional digital model wrapping the three-dimensional digital model of the tooth, with a portion of the surface of the first three-dimensional digital model corresponding to the crown being an inner surface of the three-dimensional digital model of the shell dental appliance. Then, a second three-dimensional digital model is obtained based on the first three-dimensional digital model and expanded outwards by a preset distance along the normal direction (namely, the set thickness of the shell-shaped dental instrument), and the part of the surface of the second three-dimensional digital model corresponding to the dental crown is taken as the outer surface of the shell-shaped dental instrument three-dimensional digital model. Next, a third three-dimensional digital model is generated as a shell dental implement three-dimensional digital model by joining surfaces of the first three-dimensional digital model and the second three-dimensional digital model. In one embodiment, the shell dental implement three-dimensional digital model may be an STL model.
In 1015, the non-parametric three-dimensional digital model of the shell dental implement is converted to a parametric three-dimensional digital model.
In one embodiment, the parameterized three-dimensional digital model may be in IGES (INITIAL GRAPHICS Exchange Specification) or STEP (Standard for the Exchange of Product Model Data) format.
In one embodiment, the parameterized model of the shell dental instrument may be a parameterized shell element model.
In finite element analysis, there are two common models, one is a solid unit model and the other is a shell unit model. For finite element analysis of thin-walled structures, a stable solution can be converged relatively easily using a shell-cell model. Because the shell-shaped dental instrument is also of a thin-wall structure, when a parameterized model of the shell-shaped dental instrument is generated, the shell unit model in finite element analysis can be referenced, and meanwhile, the thickness parameters can be given to the shell unit model, so that the thickness of each part of the shell-shaped dental instrument can be conveniently controlled.
In one embodiment, a parameterized shell element model with thickness parameters in IGES or STEP format may be generated based on the STL model of the shell dental instrument using Geomagic, hyperMesh, 3-matic, etc. software.
In yet another embodiment, the STL model of the shell dental instrument may be directly edited using CAE software such as HYPERMESH, LSTC, ABAQUS or Ansys, changing its data structure and assigning parameters including thickness to it to yield a parameterized shell element model.
In yet another embodiment, a parameterized shell element model of the shell dental instrument may be directly generated based on point cloud data of the STL model of the shell dental instrument.
In yet another embodiment, NURBS (Non-Uniform Rational B-Splines, i.e., non-uniform rational B-spline) curves and curved surfaces may also be used to describe the geometry of the shell dental implement. In one embodiment, a three-dimensional model may be divided into a number of curved surfaces with NURBS curves, which enclose a NURBS curved surface. Both NURBS curves and NURBS curves are functional forms, and the geometric features of the shell dental instrument parametric three-dimensional digital model can be changed by changing parameters in the functions.
The NURBS curves can be obtained based on point cloud fitting, and one NURBS curve can be used as a common boundary of two adjacent NURBS curves so as to ensure continuous splicing of the curves. Specific methods can be referred to NURBS curved surface reconstruction research based on point cloud data, which is published in volume 38 and phase 4 of the agricultural machinery journal 2007 by Zhao Jijun and Yu Chengliang.
It will be appreciated from the teachings of the present application that other suitable parametric three-dimensional digital models may be employed in addition to the parametric shell element models and NURBS curves and surfaces mentioned above, and are not exhaustive.
At 103, a parameterized three-dimensional digital model of the shell dental implement is verified.
In one embodiment, a computer may be used to determine whether a shell dental instrument represented by the shell dental instrument is acceptable based on a parameterized three-dimensional digital model of the shell dental instrument.
In one embodiment, for a shell appliance, one aspect of determining whether it is acceptable is to see if it is capable of repositioning teeth from the initial layout to the target layout for the corresponding appliance step. It will be appreciated from the teachings of the present application that the verification of the shell appliance may include, but is not limited to, whether the shell appliance is damaged during wear, whether the appliance force applied by the moving teeth is in a suitable zone during wear (different appliance movement designs, different tooth positions, the required suitable appliance force zone may be different, if the appliance force is too small, the moving teeth are not easy to move, if the appliance force is too large, periodontal tissue may be damaged), whether the force applied by the primary teeth is reasonable during wear, whether the ratio of the translational force value to the moment value applied by the moving teeth is in a suitable zone during wear, whether the extraction force of the appliance is too great, etc.
In one embodiment, a parametric three-dimensional digital model of the shell dental instrument may be verified using finite element analysis. The following is a description of an example of a test as to whether the shell appliance is capable of repositioning teeth from an initial to a target placement corresponding to the appliance step.
In one embodiment, a finite element model of the shell dental instrument and the dental jaw may be generated based on the parameterized three-dimensional digital model of the shell dental instrument and the three-dimensional digital model of the dental jaw, respectively. Then, the finite element model of the shell-shaped dental instrument can be worn on the finite element model of the dental jaw in a finite element simulation environment, and whether the shell-shaped dental instrument represented by the parameterized three-dimensional digital model is qualified or not is judged based on the layout of the teeth and the born load when the balance is achieved.
In one embodiment, the osteogenic biological process of the alveolar bone may not be considered for simplifying the calculation when calculating the effect of the shell appliance to position the teeth based on finite element simulation.
In one embodiment, the tooth may be assumed to be absolutely stiff (i.e., no displacement occurs), the load of the tooth when the mechanical static balance is achieved is calculated using a statics solution method, the displacement of the tooth in the actual situation is calculated based on the calculated load, and a parametric three-dimensional digital model of the shell dental implement is examined based thereon.
Since the periodontal ligament is an elastic body, when a tooth is subjected to a load, the tooth is displaced by elastic deformation of the periodontal ligament, but when the load is removed, the periodontal ligament is restored, and accordingly, the displacement of the tooth is also changed by restoration of the periodontal ligament. In yet another embodiment, to more accurately calculate the effect of positioning the teeth of the shell appliance, the effect of elastic deformation due to the periodontal ligament and restoration on positioning the teeth of the shell appliance can be factored.
In yet another embodiment, in order to make the simulation result more realistic, the osteogenic biological process of the alveolar bone may be simulated in a finite element simulation. In one embodiment, the osteogenic biological process of the alveolar bone may be expressed as a function f (σ, t) that varies with time and with stress distribution. At this time, the finite element model of the dental jaw may include a finite element model of a crown, a root, a periodontal ligament, and an alveolar bone (may include cortical bone and cancellous bone).
Specific methods for inspecting the shell-shaped appliance by using the finite element analysis can refer to a verification method of a shell-shaped dental appliance manufacturing process based on hot-press film forming technology in China patent application No. 201710130613.0 of the medical appliance science and technology limited company of the tin-free era, 3 rd month and 7 th month, a verification method of a shell-shaped dental appliance manufacturing process based on hot-press film forming technology in China patent application No. 201710130668.1 of the application of the 2017 3 rd month and 7 th month, a verification method of a shell-shaped dental appliance based on computer finite element analysis in China patent application No. 201710057418.X of the application of the 20171 month and 26 th month, a verification method of an accessory of a shell-shaped dental appliance based on computer finite element analysis in China patent application No. 201710057403.3 of the application of the 2017 month and 27 th month and a verification method of a computer-assisted dental appliance in China patent application No. 201710286619.7 of the application of the 2017 month and 27 th month.
In yet another embodiment, a parameterized three-dimensional digital model of the shell dental instrument may be verified based on a simplified numerical model.
In one embodiment, to simplify the calculation, the movement of the teeth can be estimated based on the stress conditions of the teeth under dynamic static balance without considering the osteogenic biological process of the alveolar bone during the correction.
Referring to fig. 2, a simplified numerical model in one embodiment of the application is schematically illustrated.
In this simplified numerical model, an alveolar bone 201 (an alveolar bone portion supporting a mobile tooth), a periodontal ligament 203 (a periodontal ligament coating a mobile tooth root), a mobile tooth 205, a shell appliance 207, an anchorage tooth 209, a periodontal ligament 211 (a periodontal ligament coating an anchorage tooth root), and an alveolar bone 213 (an alveolar bone portion supporting an anchorage tooth) form an interactive chain.
In one embodiment, the shell appliance and periodontal ligament can be reduced to individual springs, each of which parameters can be assigned by root morphology, tooth movement design, tooth placement, shell appliance morphology. The assignment of spring parameters can be based on theoretical deduction of structural mechanics and continuous mechanics, can be based on a mechanics database, and can be based on the full-element simulation method (namely, modeling the material, the shape, the boundary condition and the like according with the actual situation and simulating based on the finite element model). In one embodiment, the spring parameters may include tensile modulus and rotational modulus, respectively, that characterize the stiffness of translation and rotation of the tooth. After the assignment is carried out on the springs in the model, the displacement generated by the movement of the teeth under the action of the shell-shaped appliance can be calculated, and whether the shell-shaped appliance meets the design requirement can be judged based on the displacement.
It will be appreciated from the teachings of the present application that the three-dimensional digital model of the shell dental instrument may be inspected by sampling finite volume methods (Finite Volume Method), finite difference methods (FINITE DIFFERENCE methods), regional decomposition methods, finite point methods, boundary element methods, and the like, in addition to the finite element methods and simplified numerical models described above.
If the test results show that the shell dental instrument represented by the parameterized three-dimensional digital model is acceptable, jump to 107, otherwise jump to 105.
At 105, at least one geometric parameter of a parameterized three-dimensional digital model of the shell dental instrument is modified based on the inspection results.
The inventors of the present application have found that the forces applied to the teeth by the shell appliance are directly related to the cross-sectional shape and cross-sectional area of the shell appliance. Referring to fig. 3, in one embodiment of the present application, the relationship between the force value of the shell-shaped appliance and the cross-sectional area of the shell-shaped appliance, which the teeth bear in the mesial-distal direction and the buccal-lingual direction, is shown without a major change in the cross-sectional shape of the shell-shaped appliance. Wherein curve 301 represents the relationship between the force value of the shell appliance to which the tooth is subjected in the mesial-distal direction and the cross-sectional area of the shell appliance, curve 303 represents the relationship between the force value of the shell appliance to which the tooth is subjected in the facial-lingual direction and the cross-sectional area of the shell appliance, and interval 305 represents the more ideal range of tooth forces, which can be used to guide modification of the parameterized model of the shell appliance. In one embodiment, curves 301 and 303 may be derived by statistical methods through experimentation or simulation.
In one embodiment, if the test shows that the force applied to a tooth is too great or too small, the thickness of the corresponding portion of the shell (e.g., the portion of the shell connecting the tooth to the adjacent tooth) can be adjusted according to the curve shown in FIG. 3 so that the force applied to the tooth is in the desired zone 305.
In one embodiment, the region of the parameterized three-dimensional digital model of the shell appliance where thickness adjustment is desired can be manually selected and the thickness parameters of the selected region modified. In one embodiment, the modification to the thickness parameter may be a direct input of a thickness value that needs to be increased or decreased, and in yet another embodiment, the modification to the thickness parameter may also be a function to control the thickness taper such that the thickness transition is smoother.
The inventors of the present application have found that the thickness of the various portions of the shell appliance made based on the conventional hot-pressed film process is about the same, in which case the more the teeth that are closer to the moving teeth are subjected to the greater the anchorage, the uneven distribution of the anchorage may cause the adjacent moving teeth to be subjected to excessive anchorage or the moving teeth to be insufficiently anchorage.
The inventors of the present application have found that the magnitude of the force applied by a shell appliance to a tooth is positively correlated with the thickness of the portion of the shell appliance corresponding to that tooth, the greater the thickness, the greater the force. In order to make the distribution of the anchorage more reasonable, so as to protect the anchorage teeth and ensure the correction effect, the aim of adjusting the distribution of the anchorage can be achieved by adjusting the thickness of the corresponding part of the side wall (covering the labial cheek side and the lingual side) of the shell-shaped appliance.
Referring to fig. 4, a partial thickness profile of a shell appliance in one embodiment of the application is schematically illustrated.
Teeth 401 are moving teeth and teeth 403, 405 and 407 are all anchorage teeth. In one embodiment, to equalize the resistance of the anchorage teeth, the thickness of the shell appliance may be gradually increased from the adjacent teeth 403 of the movable teeth 401 in a direction away from the movable teeth 401, which may equalize the resistance of the anchorage teeth 403, 405, and 407.
As is known in the art, different teeth can withstand different forces, e.g., a molar can withstand a greater force than an anterior tooth. In one embodiment, the thickness of the various portions of the shell appliance can be adjusted based on the anchorage capacity of the different teeth, and the larger anchorage capacity of the teeth can be assigned a greater anchorage capacity, thereby fully and reasonably utilizing the anchorage teeth.
In one embodiment, the thickness of the parameterized three-dimensional digital model of the shell dental implement is locally adjusted, leaving the inner surface unchanged without modification to its inner surface (the surface surrounding the teeth), and the local thickness adjustment only changes the geometry of the outer surface.
The inventors of the present application found that, in the case of opening the gaps between teeth, the force applied by the shell appliance to the teeth was related to the area where it wrapped around the teeth. When the wrapping area is too small, the shell-shaped appliance lacks enough force application points to the teeth, which may cause insufficient force application, and when the wrapping contact area is too large, the rigidity of the shell-shaped appliance at the tooth gap part may be insufficient, which may eventually cause insufficient force application. Referring to fig. 5, a graph 501 representing the relationship between package contact area and force value is schematically illustrated in one embodiment of the present application.
Referring to fig. 6A, an example of an excessive area of wrap around teeth resulting in an appliance having insufficient rigidity at the interproximal areas is schematically illustrated. Because shell-like appliance 601 enters the gap between teeth 603 and 605 too deeply, its area surrounding teeth 603 and 605 is too large, resulting in insufficient rigidity in the mesial-distal direction at the site where teeth 603 and 605 are joined, resulting in too little force being applied in the mesial-distal direction to open the gap between teeth 603 and 605, lying within section 503 shown in fig. 5.
In one embodiment, the configuration of the portion of shell appliance 601 that connects between teeth 603 and 605 can be modified to reduce the curvature of the portion in the mesial-distal direction to flatten it and thereby increase its stiffness. Referring to fig. 6B, a shell appliance 601' is schematically shown with the site connecting teeth 603 and 605 modified.
For some orthodontic cases, to facilitate adjustment of the tooth pose, the posterior bite needs to be opened.
In one embodiment, the condition of the verification may include whether the shell-like appliance is open to the desired degree. The parameterized three-dimensional digital model of the shell appliances may be modified based on the results of the verification to increase the thickness of specific areas of the occlusal surfaces of the upper and/or lower shell appliances so that the shell appliances they represent can open the bite to a desired extent.
Referring to fig. 7, a schematic representation of a shell appliance cross-sectional profile from a buccal lingual view is shown in one embodiment of the application. To open the bite, the thickness of the occlusal surface of the shell appliance 701 is increased to correspond to the area of the posterior teeth 703 where it forms the bite pad 705, and at the same time, the thickness of the occlusal surface of the shell appliance 711 is increased to correspond to the area of the posterior teeth 713 where it forms the bite pad 715. Upon bite, bite pads 705 and 715 abut, thereby opening the bite. In one embodiment, bite pads 705 and 715 may be contoured to match each other to reduce the chance of bite slippage.
After the modification is completed, the process jumps to 103 to check the modified parametric three-dimensional digital model of the shell dental instrument, and the process is circulated until a qualified parametric three-dimensional digital model of the shell dental instrument is obtained.
At 107, a 3D printed digital file is generated based on the parameterized three-dimensional digital model of the shell dental instrument passing the verification.
Currently, the more commonly used 3D printed digital files are STL and STP format files. Although some manufacturers' 3D printing devices support OBJ, BREP, MAX, 3DM, 3DS, x_ T, SKP, SLDPRT, PRT, ASM, F3D, FBX, RVT, WIRE, etc. format files, it is rare. The following examples will be described with reference to a shell element model to STL file.
In one embodiment, if the shell element is triangular, the shell element model can be converted into the STL file by importing, converting and exporting the shell element model by using preprocessing software of CAE business software such as HYPERMESH, LSTC, ABAQUS and Ansys.
After the parameterized model is converted to the STL file, the surfaces and curves are replaced and converted to mesh, forming a series of triangle patches and point cloud data representing the exact geometric meaning of the prototype.
In one embodiment, the 3D printing device may be inspected and repaired to ensure that the triangular patches form a fully enclosed surface before it is controlled to perform 3D printing using the STL file.
At 109, a shell dental appliance is fabricated using the 3D printed digital file to control a 3D printing device.
Currently, 3D printing devices suitable for use in fabricating shell dental appliances include light curing molding (Stereo Lithography Appearance, SLA) devices (such as those provided by 3D Systems), digital light processing (DIGITAL LIGHT Procession, DLP) devices (such as those provided by Envision TEC), and polymer jetting (PolyJet) devices (such as those provided by Stratasys), among others.
After the 3D printed digital file is obtained, it can be used to control the 3D printing device to make a shell dental appliance.
Although various aspects and embodiments of the present application are disclosed herein, other aspects and embodiments of the present application will be apparent to those skilled in the art from consideration of the specification. The various aspects and embodiments disclosed herein are presented for purposes of illustration only and not limitation. The scope and spirit of the application are to be determined solely by the appended claims.
Likewise, the various diagrams may illustrate exemplary architectures or other configurations of the disclosed methods and systems, which facilitate an understanding of the features and functions that may be included in the disclosed methods and systems. The claimed subject matter is not limited to the example architectures or configurations shown, but rather, desired features may be implemented with various alternative architectures and configurations. In addition, with regard to the flow diagrams, functional descriptions, and method claims, the order of the blocks presented herein should not be limited to various embodiments that are implemented in the same order to perform the described functions, unless the context clearly indicates otherwise.
Unless explicitly indicated otherwise, the terms and phrases used herein and variations thereof are to be construed in an open-ended fashion, and not in a limiting sense. In some instances, the occurrence of such expansive words and 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 represent a narrowing case in examples where such expansive terms may not be available.
Claims (7)
1. A method of making a shell dental appliance comprising:
acquiring a three-dimensional digital model of the tooth;
Generating a non-parametric three-dimensional digital model of a shell dental implement based on the three-dimensional digital model of the tooth;
generating a parametric three-dimensional digital model of the shell dental instrument based on the non-parametric three-dimensional digital model of the shell dental instrument;
modifying a thickness parameter of a localized region of a parameterized three-dimensional digital model of the shell dental instrument;
Generating a 3D printed digital file based on the parameterized three-dimensional digital model of the modified shell dental instrument, and
And controlling the 3D printing equipment to manufacture the shell-shaped dental appliance by using the 3D printing digital file.
2. The method of claim 1, wherein the shell dental appliance is a shell appliance for repositioning teeth from a first configuration to a second configuration.
3. The method of claim 1, wherein the non-parametric three-dimensional digital model expresses geometry in geometric data alone, and wherein the parametric three-dimensional digital model expresses geometry in both geometric data and a parametric description.
4. The method of claim 1, wherein the parametric three-dimensional digital model is a parametric shell-unit model.
5. The method of claim 1, further comprising inspecting a parametric three-dimensional digital model of the shell dental instrument, wherein modifying the parametric three-dimensional digital model of the shell dental instrument is based on a result of the inspecting.
6. The method of manufacturing a shell dental instrument of claim 5, wherein the verification is based on finite element analysis.
7. The method of claim 1, wherein the non-parametric three-dimensional digital model is an STL model.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010067433.4A CN113134969B (en) | 2020-01-20 | 2020-01-20 | Methods for manufacturing shell-shaped dental instruments |
| PCT/CN2020/113791 WO2021147335A1 (en) | 2020-01-20 | 2020-09-07 | Method for manufacturing shell-shaped dental instrument |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010067433.4A CN113134969B (en) | 2020-01-20 | 2020-01-20 | Methods for manufacturing shell-shaped dental instruments |
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| CN113134969B true CN113134969B (en) | 2025-11-04 |
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| CN113134973A (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 with accessories |
| 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 |
| CN114404078B (en) * | 2022-01-04 | 2023-05-23 | 深圳技术大学 | Preparation method of invisible appliance and invisible appliance |
| CN117503393A (en) * | 2022-07-29 | 2024-02-06 | 上海时代天使医疗器械有限公司 | Method for producing cutting lines for shell-shaped dental instruments |
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| WO2021147335A1 (en) | 2021-07-29 |
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