Simulation device, program, and simulation method

Abstract

Provided are a simulation apparatus, a program for simulation, and a simulation method that are lighter in load for calculation processing and capable of accurate simulation than conventional techniques. A simulation apparatus 1 that predicts the movement of teeth when performing orthodontic treatment on a patient's teeth using an aligner, comprising a movement calculation unit 13 that calculates a predetermined tooth arrangement state based on the patient's tooth information and aligner information, wherein the movement calculation unit 13 calculates the arrangement state based on the orthodontic force by the aligner and the magnitude of the load generated by the surrounding tissues of a predetermined tooth, and the movement calculation unit 13 calculates the magnitude of the load using an attenuation model that attenuates according to a predetermined characteristic over time and calculates the arrangement state.

Description

Technical Field

[0001] The present disclosure relates to a simulation device, program, and simulation method for orthodontic treatment using an aligner.

Background Art

[0002] In recent years, orthodontic treatment using an aligner has been performed. In this orthodontic treatment using an aligner, the aligner individually created according to the patient's condition is worn by the patient according to a preset plan, thereby correcting the teeth. An aligner is a mouthpiece-shaped orthodontic appliance formed from a material having a certain degree of elasticity. This aligner is designed such that when worn by a patient, the portion corresponding to the teeth that need to be corrected (the teeth to be corrected) is stretched by a certain ratio. For this reason, when the patient wears the aligner, a force that the stretched portion of the aligner tries to return acts on the teeth to be corrected. The teeth are corrected by this force.

[0003] Since there is a limit to the distance by which teeth can be moved by a single aligner, in actual orthodontic treatment, a plurality of aligners are used. That is, the orthodontic treatment is performed by the patient wearing a plurality of pre-made aligners in a predetermined order.

[0004] Since an aligner is generally made of a soft material, the patient feels less discomfort than in conventional orthodontic treatment using brackets, wires, etc. Also, since an aligner is formed of a transparent resin or the like, it is said to be superior in aesthetics to conventional orthodontic treatment using brackets, wires, etc.

[0005] On the other hand, if the aligner design is inappropriate, the teeth to be corrected may move to a position different from the ideal position or may tilt more than the ideal state. In addition, since orthodontic treatment takes a long time until its completion, it is difficult to determine whether the aligner design is appropriate before starting orthodontic treatment. For this reason, as shown in Patent Document 1, for example, a simulation is performed using a computer to confirm the effect of orthodontic treatment in advance.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In the technology described in Patent Document 1 above, in order to analyze the interaction of forces acting between the orthodontic appliance and the teeth, complex computational processes such as finite element analysis are performed. For this reason, it is necessary to use a CPU having a high computing power, and furthermore, an enormous amount of time is required to execute the necessary computational processes.

[0008] On the other hand, in order to improve the processing speed, simulations according to simple theories are also being carried out. For example, it is also assumed that the teeth to be corrected translate by an external force, and a simulation is performed with simple arithmetic processing. However, in such a simulation, while the processing speed can be improved, the result may become inaccurate. That is, there is a possibility that an analysis process that does not appropriately reflect the actual movement of the teeth in orthodontic treatment is performed.

[0009] The present disclosure discloses an example of a simulation apparatus, a program, and a simulation method for orthodontic treatment that can perform accurate analysis processing with a lighter load for calculation processing than conventional techniques using calculation processing such as complex finite element analysis.

Means for Solving the Problems

[0010] To achieve the above object, the present disclosure provides the following means. The simulation apparatus of the present disclosure is a simulation apparatus that predicts the movement of a patient's teeth when performing orthodontic treatment of the patient's teeth using an aligner. The simulation apparatus of the present disclosure includes a movement calculation unit that calculates an arrangement state indicating the arrangement position and posture of a predetermined tooth after orthodontic treatment based on the patient's tooth information and the aligner information. The tooth information is information including at least information regarding the shape of each tooth of the patient, information indicating the arrangement state of the patient's teeth before orthodontic treatment, and information regarding the surrounding tissues of the patient's teeth. The aligner information is information including at least information regarding the shape and physical properties of the aligner. Then, the movement calculation unit calculates the arrangement state based on the orthodontic force applied to a predetermined tooth by the aligner and the magnitude of the load generated by the surrounding tissues of the predetermined tooth when the orthodontic force is applied to the predetermined tooth. At this time, the movement calculation unit calculates the magnitude of the load using a decay model that decays according to a predetermined characteristic over time, and calculates the arrangement state.

[0011] By being configured as described above, an accurate simulation considering the characteristics of the tissues surrounding the teeth can be performed. That is, the simulation apparatus of the present disclosure can accurately predict the movement of a predetermined tooth due to orthodontic treatment and the arrangement state of the teeth after orthodontic treatment, considering the characteristics of the tissues surrounding the teeth, without performing complex arithmetic processing as in the prior art.

[0012] In the above disclosure, the attenuation model is preferably a mathematical model based on the creep phenomenon of a predetermined substance. By doing so, without performing complex arithmetic processing, by calculating the magnitude of the load considering the characteristics of the actual surrounding tissue, the arrangement state of the teeth after orthodontic treatment can be accurately predicted.

[0013] In the above disclosure, the movement calculation unit preferably calculates the arrangement state using a simple model in which the aligner, the patient's teeth, and the surrounding tissue of the teeth are each represented by a plurality of beam elements having a beam-like shape, based on the tooth information and the aligner information. Each of the beam elements constituting this simple model corresponds to a part of any one of the aligner, the teeth, and the surrounding tissue of the teeth, and the movement calculation unit preferably calculates the arrangement state assuming that each beam element has a bending stiffness and a torsional stiffness corresponding to the physical properties of the part to which they correspond.

[0014] With this configuration, since the aligner, the teeth, and the surrounding tissue of the teeth are each represented by a simple model, a simulation considering the interaction between them can be performed with a reduced computational load for analysis processing. That is, an accurate simulation reflecting the characteristics of each part can be performed at an improved processing speed.

[0015] In the above disclosure, when an attachment used for orthodontic treatment is provided on a tooth, the movement calculation unit preferably sets the torsional stiffness of the beam element corresponding to the part of the aligner related to the tooth provided with the attachment to a larger value than when no attachment is provided on the tooth to be orthodontically treated, and calculates the arrangement state.

[0016] With the above configuration, a simulation appropriately reflecting the characteristics when an attachment is provided on a predetermined tooth can be performed without performing an additional process.

[0017] Furthermore, the present disclosure also includes a program for operating an electronic computing device (computer) as the above-described simulation device, and a simulation method for performing similar processing.

Advantages of the Invention

[0018] According to the simulation device, program, and simulation method of the present disclosure, it is possible to perform an accurate simulation in which the characteristics of each part are reflected at a processing speed improved from the conventional technology.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

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Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Modes for Carrying Out the Invention

[0020] The simulation device 1 of the present disclosure will be mainly described with reference to FIGS. 1 to 7. In the following description, the front-back, left-right, and up-down directions shall be the directions shown in the figures respectively unless otherwise specified. Also, the oral side of the patient's teeth is described as the inner side, and the opposite side (lip side or buccal side) (oral vestibule side) is described as the outer side. Further, the surface facing the outside of the patient's teeth is also described as the outer surface or vestibular surface, and the surface on the oral side of the patient's teeth is also described as the inner surface or oral surface. Also, when the teeth are in occlusion, the surface on the occluding side with the opposing teeth (the surface where food etc. is chewed) is also described as the occlusal surface.

[0021] 1. Description of the configuration First, the configuration of the simulation device 1 will be described. The simulation device 1 is a general-purpose computer (electronic computing device) installed with dedicated software (program). The simulation device 1 mainly includes a computer main body 10, an input device 3, and a display / output device 4 (see FIG. 1). The simulation device 1 may further include additional configurations different from the above.

[0022] The computer main body 10 has configurations typically provided in a general-purpose computer or server device, such as a CPU 5, a memory 6 such as a RAM and a ROM, and an interface unit 7. Examples of the interface unit 7 include a communication interface and an input / output device interface. The computer main body 10 also includes a storage unit 2 which is a general-purpose storage device such as a hard disk or an SDD. The storage unit 2 may be built-in to the computer main body 10 or externally attached. Alternatively, it may be a storage device that is accessible and connected to a network to which the computer main body 10 is connected, or a storage device provided in another computer or server device connected to the same network. Also, the storage unit 2 may be a combination of a plurality of storage devices. The configuration of the computer main body 10 is not limited to the above as long as it can realize each of the functions described below.

[0023] The input device 3 is a device such as a mouse or a keyboard that a user operates. The display / output device 4 is an output device that performs an output according to an output signal from the computer main body 10. Examples of the display / output device 4 include a display device such as an LCD display and a printer, but it is not particularly limited.

[0024] The simulation device 1 reads a dedicated program installed in the storage unit 2 or the like, and by operating in cooperation with hardware such as the CPU 5, the memory 6, and the interface unit 7, realizes the functions of each part described hereinafter.

[0025] Specifically, the simulation device 1 realizes each function of the information acquisition unit 11, the array calculation unit 12, the movement calculation unit 13, and the display signal output unit 14 by the cooperation of a dedicated program and the hardware constituting the computer. In other words, the simulation device 1 includes an information acquisition unit 11, an array calculation unit 12, a movement calculation unit 13, and a display signal output unit 14 (see FIG. 2). Details of the functions of each part will be described later. Note that the simulation device 1 may be composed of dedicated hardware having the functions of each part described below.

[0026] The information acquisition unit 11 has a function of acquiring information regarding the shape of teeth, information regarding the shape of surrounding tissues, and information regarding the characteristics of tissues from the three-dimensional information of a patient acquired by an X-ray CT device or the like. Hereinafter, information including at least information regarding the teeth of the patient and the surrounding tissues acquired by the information acquisition unit 11 is also referred to as "tooth information".

[0027] Tooth information includes at least information regarding the shape of each tooth of the patient and information indicating the patient's dental occlusion (tooth arrangement state) before orthodontic treatment. For example, it includes at least information regarding the three-dimensional shape of the crown and root portions of the teeth in each of the patient's upper and lower dental arches, information regarding the arrangement position and posture (inclination) of each tooth, and information indicating the arrangement state of each tooth.

[0028] In addition, tooth information also includes information regarding the tissues surrounding the teeth. The tissues surrounding the teeth are parts such as the gingiva, alveolar bone, and periodontal ligament. In the following description, the tissues surrounding the patient's teeth described above will also be referred to as "tissues surrounding the teeth" or simply "surrounding tissues".

[0029] Information regarding the tissues surrounding the teeth includes, for example, information indicating the shape of the alveolar bone and the distance between the alveolar bone and the corresponding tooth (the thickness of tissues such as the periodontal ligament). In addition, information regarding the tissues surrounding the teeth also includes information representing their characteristics. Examples of information representing the characteristics of the surrounding tissues include the patient's bone density, but information representing other physical or physiological characteristics of the tissues surrounding the teeth may also be included.

[0030] Tooth information also includes information regarding the attachment when an attachment is provided on a specific tooth. That is, it also includes information regarding the position of the tooth on which the attachment is provided and the shape of the attachment. Details of the case where an attachment is provided on a tooth will be described later.

[0031] The information acquisition unit 11 acquires information in which the three-dimensional information regarding the forms of teeth and their surrounding tissues included in the acquired tooth information is converted into general-purpose data conforming to a predetermined format. As this general-purpose data, STL data is exemplified. Note that the information acquisition unit 11 may acquire information converted into data conforming to other formats. Hereinafter, the data converted by the information acquisition unit 11 is also referred to as "STL information". The tooth information acquired by the information acquisition unit 11 and the converted STL information are stored in the storage unit 2. Note that the information acquisition unit 11 may have a function of converting information acquired by an X-ray CT apparatus or the like into general-purpose data such as STL information. Further, the information acquisition unit 11 also has a function of acquiring information regarding a patient, information regarding an aligner, etc. based on information input by the user using the input device 3 or the like. Examples of the information regarding the patient include information regarding the bone density of the patient, information regarding the age of the patient, etc. Examples of the information regarding the aligner include information such as the material of the aligner.

[0032] The array calculation unit 12, the movement calculation unit 13, and the display signal output unit 14 are mainly parts that perform analysis processing for simulation and output processing of the results. The array calculation unit 12 has a function as a preprocessor for the analysis processing.

[0033] The array calculation unit 12 has a function of generating three-dimensional information indicating an ideal tooth arrangement state after orthodontic treatment according to an operation by the user. Specifically, it has a function of creating three-dimensional information (information indicating an ideal tooth arrangement) showing the state in which the patient's teeth are arranged in an ideal state, which is set by the user operating the input device 3 or the like.

[0034] Furthermore, the array calculation unit 12 has a function of creating information regarding the aligner used for orthodontic treatment. The information regarding the aligner includes information regarding the dimensions of the aligner required for the analysis processing. The information regarding the dimensions of this aligner includes at least information regarding the dimensions of each part of the aligner and information regarding the deformation ratio of the aligner when orthodontic treatment is performed.

[0035] Specifically, the array calculation unit 12 has a function of calculating information on the dimensions of each part of the aligner corresponding to the patient's teeth based on information on the shape of teeth and the like included in the patient's tooth information and information indicating the ideal tooth arrangement state set by the user. Further, the array calculation unit 12 has a function of calculating the deformation ratio of the aligner during orthodontic treatment as one of the information on the dimensions of the aligner. That is, the array calculation unit 12 has a function of calculating, as one of the information on the dimensions of the aligner, how much (how much it needs to be stretched) the aligner needs to be deformed from its original state in order to move the teeth to be corrected to the ideal position set by the user. As described above, in orthodontic treatment using an aligner, when the patient wears the aligner, the part corresponding to the teeth to be corrected of the aligner is stretched (deformed), and the teeth are corrected by the force that the part tries to return to its original state. That is, the movement distance (orthodontic movement distance) required to move the teeth to be corrected to the ideal position corresponds to the amount by which the aligner is deformed (the length by which it is stretched) for orthodontic treatment. Therefore, the array calculation unit 12 calculates the movement distance (orthodontic movement distance) required to move the teeth to be corrected to the ideal position based on the information indicating the ideal tooth arrangement state set by the user and the information indicating the tooth arrangement state before orthodontic treatment. And it has a function of storing the calculated orthodontic movement distance in the storage unit 2 as the amount by which the aligner is deformed during orthodontic treatment.

[0036] Since the distance that the teeth to be corrected can be moved with one aligner is limited, in actual orthodontic treatment, a plurality of aligners are used. That is, the amount by which the aligner is deformed during orthodontic treatment is the sum of the respective deformation amounts (the lengths by which they are stretched) of each aligner used for orthodontic treatment. In other words, the orthodontic movement distance corresponds to the sum of the deformation amounts (the lengths by which they are stretched) of each aligner used for orthodontic treatment.

[0037] In addition, the array calculation unit 12 also has a function of calculating the number of aligners required for orthodontic treatment. As described above, the distance that the teeth to be corrected can be moved by one aligner is limited. Therefore, the array calculation unit 12 has a function of calculating the number of aligners required for orthodontic treatment based on the moving distance required to move the teeth to be corrected to an ideal position and the distance that the teeth to be corrected can be moved by one aligner.

[0038] Furthermore, the array calculation unit 12 has a function of calculating the force that the teeth to be corrected receive from the aligner during the orthodontic treatment period. Hereinafter, the force that the patient's teeth receive from the aligner, in other words, the force acting on a predetermined tooth by the aligner, is also referred to as "orthodontic force". The array calculation unit 12 calculates the magnitude of the orthodontic force using an orthodontic force calculation model, the details of which will be described later, based on the information regarding the dimensions of the aligner and the information regarding the physical properties of the aligner.

[0039] The information regarding the physical properties of the aligner is information indicating physical characteristics of the material constituting the aligner. The information regarding the physical properties of this aligner includes, for example, information such as the bending rigidity and torsional rigidity of the material (material) constituting the aligner.

[0040] In the following description, the above-mentioned information regarding the aligner is also referred to as "aligner information". That is, the information regarding the aligner used for the patient's orthodontic treatment, such as the information regarding the dimensions of the aligner and the information regarding the physical properties of the aligner, is also collectively referred to as "aligner information".

[0041] Furthermore, the array calculation unit 12 has a function of creating a simplified model in which the patient's teeth, the surrounding tissues, and the aligner are represented in a shape simpler than the actual shape. Specifically, the array calculation unit 12 has a function of creating a simplified model in which each part of the teeth, the surrounding tissues, and the aligner is represented by a plurality of beam elements having a beam-like shape based on the tooth information and the aligner information. The details of the simplified model will be described later.

[0042] The movement calculation unit 13 is a part that analyzes the forces acting on predetermined teeth of a patient by orthodontic treatment using an aligner and calculates the movement of the teeth due to the orthodontic treatment by the aligner. In other words, the movement calculation unit 13 analyzes the forces acting on each of the patient's teeth affected by the worn aligner and calculates the movement of each tooth. Referring to FIG. 3(a) for explanation, generally when a patient wears the aligner 26, the crown portion 20a where the aligner 26 is worn receives a corrective force F from the aligner 26 in the direction in which the stretched portion of the aligner 26 tries to return to its original state. On the other hand, since the tooth root portion 20b is surrounded by surrounding tissues such as the dental stem 23, the periodontal ligament 24, and the alveolar bone 25, when the corrective force F acts, it receives a force (load R) in the direction opposite to the direction of the corrective force F from the surrounding tissues (see FIG. 3(a)).

[0043] It is known that in a state where a force in a predetermined direction is applied, the magnitude of the load R (resistance) received by a tooth from its surrounding tissues decreases with the passage of time. The movement calculation unit 13 has a function of calculating the magnitude of this load R using an attenuation model that decreases according to a predetermined characteristic with the passage of time. Details of the attenuation model will be described later.

[0044] In addition, the movement calculation unit 13 has a function of calculating the arrangement position and posture (tilt) of each tooth after orthodontic treatment using the simple model created by the arrangement calculation unit 12, the corrective force by the aligner, and the attenuation model. Hereinafter, the state indicating the arrangement position and posture of a predetermined tooth will also be referred to as the "arrangement state". The movement calculation unit 13 also has a function of creating information indicating the tooth alignment (tooth arrangement state) at that time based on the calculated arrangement state of each tooth.

[0045] The display signal output unit 14 is a part that performs post - processing in the analysis process. It has the function of generating a three - dimensional image based on the STL information converted by the information acquisition unit 11 and the analysis results calculated by the movement calculation unit 13. Hereinafter, the image created based on the STL information will also be referred to as the "STL image". That is, the display signal output unit 14 has the function of generating three - dimensional image information representing the arrangement state of each tooth based on the STL information stored in the storage unit 2 and the analysis processing results performed by the movement calculation unit 13. The three - dimensional image information generated by the display signal output unit 14 is output to the display / output device 4. In the following description, the three - dimensional image showing the tooth alignment state of the patient before orthodontic treatment will also be referred to as the "three - dimensional image before orthodontic treatment". Also, the three - dimensional image showing the ideal tooth alignment state set according to the operation by the user will also be referred to as the "three - dimensional image of the ideal tooth alignment".

[0046] The storage unit 2 is a part where information necessary for the simulation is stored. A dedicated program for performing the simulation is stored in the storage unit 2. Also, the storage unit 2 stores the patient's tooth information, STL information, information regarding the ideal arrangement state of the patient's teeth set by the user, and information calculated by the movement calculation unit 13, etc.

[0047] Also, the storage unit 2 stores information regarding the physical properties of the aligner. Specifically, information regarding the physical properties of the materials generally used to form the aligner is stored in association with information representing the name and type of the material. Also, the storage unit 2 stores information regarding the orthodontic force calculation model and information regarding the attenuation model, the details of which will be described later.

[0048] 2. Regarding the orthodontic force calculation model Since the aligner is formed from an elastic material, when the aligner is deformed by stretching or the like, a force that tries to return it to its original state is generated. The magnitude of this force that tries to return to its original state changes according to the deformation ratio of the aligner. That is, the aligner has the property that when its change ratio is large, a large force (corrective force) is generated, and as its deformation ratio decreases, the magnitude of that force decreases. Here, the deformation ratio is information (change amount) indicating how much the shape of the aligner has deformed from its original state.

[0049] The simulation device 1 calculates the corrective force based on the above characteristics of the aligner. Specifically, using a corrective force calculation model, which is a mathematical model representing the relationship between the deformation ratio (change amount) of the aligner and the corrective force (the force that tries to return from the deformed state to its original state) as exemplified in FIG. 4, the magnitude of the corrective force generated when the aligner is worn is calculated. The simulation device 1 calculates the deformation ratio of the aligner when a predetermined aligner is worn by a patient based on the aligner information and the tooth information. Then, the simulation device 1 refers to the corresponding corrective force calculation model based on the calculated deformation ratio and calculates the corrective force.

[0050] Since the relationship between the deformation ratio (change amount) of the aligner and the corrective force differs depending on the material that constitutes the aligner, a plurality of corrective force calculation models corresponding to the material of the aligner are stored in the storage unit 2 (see FIG. 4). FIG. 4 shows three corrective force calculation models M1, M2, and M3 with different characteristics according to the material of the aligner. That is, according to the information regarding the material of the aligner input by the patient, one of the corrective force calculation models M1, M2, and M3 is selected and the corrective force is calculated. Note that FIG. 4 is an example, and the number of corrective force calculation models and their characteristics are not limited to the content shown in FIG. 4.

[0051] 3. Regarding the attenuation model As described above, in a state where an orthodontic force is acting on a tooth, it is known that the magnitude of the load R (resistance) received by the tooth from its surrounding tissues decreases (attenuates) according to a predetermined characteristic over time. This is because the tissue on the side of the alveolar bone surrounding the tooth root that is receiving the force by the orthodontic force (the tissue in the region P surrounded by the broken line in Fig. 3(a)) dies due to the pressure from the reaction force of the load R received by the tooth, and the tissue on the opposite side (the tissue in the region Q surrounded by the broken line in Fig. 3(a)) grows. For this reason, it is known that the magnitude of the load (resistance) received by the tooth to which the orthodontic force is applied decreases (attenuates) according to the same characteristic (tendency) in generally any patient.

[0052] The simulation device 1 calculates the magnitude of the load (resistance) at a predetermined time using an attenuation model (see Fig. 5), which is a mathematical model representing the decrease in the load according to a predetermined characteristic over time. This predetermined characteristic is such that the magnitude of the load decreases at a large rate in the initial certain period, gradually the rate of decrease becomes gentler, and then it decreases gently as exemplified in Fig. 5. The movement calculation unit 13 performs a process of calculating the magnitude of the load (resistance) received by the tooth under the orthodontic force from the surrounding tissues by referring to this attenuation model based on the time elapsed after the aligner is worn.

[0053] This attenuation model is a mathematical model created by paying attention to the fact that the characteristics that occur in the surrounding tissues when a corrective force acts on a patient's tooth are similar to the characteristics of the creep phenomenon of a specific substance, based on the results of physical experiments using multiple clinical models and the analysis data thereof. That is, this attenuation model is a mathematical model created by paying attention to the fact that the characteristics based on the physiological phenomena that occur in the surrounding tissues such as the alveolar bone when a corrective force acts on a patient's tooth have characteristics similar to the creep phenomenon, which is one of the physical phenomena. Here, the specific substance is any substance in which the characteristics based on the physiological phenomena occurring in the surrounding tissues and the creep phenomenon with similar characteristics occur, and it may be a substance different from the substances included in the composition of the surrounding tissues of the patient's tooth, or it may be the same substance as the substances included in the composition of the surrounding tissues of the patient's tooth.

[0054] The attenuation model is created to have the same characteristics as the characteristics of the phenomena that occur in the actual surrounding tissues such as the alveolar bone, based on the results of physical experiments using a clinical model that reflects the characteristics of the actual tissue and the analysis data thereof. The clinical model used in this physical experiment is a model created based on a plurality of clinical data (tooth information) obtained from a plurality of patients and subjects, and reflects the physical characteristics of the teeth and their surrounding tissues of the human body. It has been confirmed that the attenuation model can obtain results very close to the results of physical experiments using the clinical model.

[0055] It is known that the magnitude of the load (resistance) received by a tooth to which a corrective force is applied from the surrounding tissues and the characteristics of its attenuation vary depending on the state of the surrounding tissues. For example, it is known that the characteristics of the load (resistance) received from the surrounding tissues differ depending on the patient's bone density, the patient's age, etc. Therefore, the memory unit 2 stores a plurality of attenuation models corresponding to information about the patient such as the patient's age and bone density. FIG. 5 shows three attenuation models m1, m2, and m3 with different characteristics according to the patient's bone density. That is, the attenuation models m1, m2, and m3 are selected according to the information about the patient such as the bone density input by the user, and the magnitude of the load (resistance) received from the surrounding tissues is calculated. Note that FIG. 5 is an example, and the number of attenuation models and their characteristics are not limited to the content shown in FIG. 5.

[0056] 4. About the simple model Hereinafter, the simple model used in the analysis process will be described. The simple model used in the simulation device 1 of the present disclosure is a model in which the patient's teeth, their surrounding tissues, and the aligner are represented by a plurality of beam elements having a beam shape. The array calculation unit 12 divides the parts such as the patient's teeth, the surrounding tissues, and the aligner according to predetermined conditions, and generates beam elements corresponding to the divided parts. Specifically, the array calculation unit 12 generates beam elements corresponding to the divided parts based on the tooth information and the aligner information. Then, the array calculation unit 12 generates a simple model in which each of the divided parts is replaced with the generated beam element. That is, the array calculation unit 12 generates a simple-shaped model in which the information about the dimensions of each part of the actual teeth, their surrounding tissues, and the aligner and the information about the physical properties of each part are reflected.

[0057] Hereinafter, with reference mainly to FIGS. 3(b) and 6, the details of the simplified model will be described. In FIG. 3(b), two adjacent teeth 30 and 40 on the upper jaw side of the patient, the surrounding tissue 60 of the teeth 30 and 40, and an aligner part 50P which is a part of the aligner 50 used for orthodontic treatment are shown. Here, specifically explaining the aligner part 50P, the aligner part 50P is about half of the regions of the outer surface, inner surface, and occlusal surface of the tooth 30 (about half of the region on the side of the tooth 40), and further about half of the regions of the outer surface, inner surface, and occlusal surface of the tooth 40 (about half of the region on the side of the tooth 30), which is the part of the aligner 50 covering these regions. The region shaded in FIG. 3(b) is the aligner part 50P.

[0058] Hereinafter, the approximately half regions on the adjacent sides of each of the two adjacent teeth as described above are collectively referred to as the interval between the two teeth. For example, the part of the tooth 30 on the side of the tooth 40 and the part of the tooth 40 on the side of the tooth 30, whose occlusal surface sides are covered by the aligner part 50P as described above, are collectively referred to as the interval between the tooth 30 and the tooth 40.

[0059] FIG. 6 shows a simplified model 100 corresponding to FIG. 3(b). In FIG. 6, the positive direction of the X-axis corresponds to the direction from the patient's oral cavity to the outside, and the negative direction of the X-axis corresponds to the direction toward the inside.

[0060] In the simplified model 100, the tooth 30 is represented by a beam part 30A in which a beam element 31a and a beam element 31b are linearly connected at a node 33. The beam element 31a is the part indicated by a two-dot chain line connecting between the node 32 and the node 33 in FIG. 6, and the beam element 31b is the part indicated by a two-dot chain line connecting the node 33 and the node 34. The beam element 31a corresponds to the crown part of the tooth 30, and the beam element 31b corresponds to the root part of the tooth 30. Similarly, the tooth 40 is represented by a beam part 40A in which a beam element 41a and a beam element 41b are linearly connected at a node 43. The beam element 41a is the part indicated by a two-dot chain line connecting between the node 42 and the node 43, and the beam element 41b is the part indicated by a two-dot chain line connecting the node 43 and the node 44.

[0061] In the simplified model 100, the aligner portion 50P covering the section between the teeth 30 and 40 is represented by four beam elements 51f, 51r, 52f, and 52r. The beam elements 51f and 52f correspond to the portions disposed on the outer surfaces of the teeth 30 and 40. The beam elements 51r and 52r correspond to the portions disposed on the inner surfaces of the teeth 30 and 40. The beam elements 51f and 51r correspond to the portions disposed on the occlusal surface side of the section between the teeth 30 and 40, and the beam elements 52f and 52r correspond to the portions disposed on the gingival side of the section between the teeth 30 and 40.

[0062] If the number of beam elements representing the aligner portion 50P is two or more, it may be represented by a number of beam elements different from four. For example, it may be represented by two or three beam elements, or may be represented by five or more beam elements.

[0063] In the simplified model 100, the node 32 corresponds to the portion of the occlusal surface of the tooth 30 that protrudes most in the direction away from the tooth root. The node 35 corresponds to the portion that protrudes most inwardly or outwardly of the inner or outer surface of the tooth 30. The same applies to the nodes 42 and 45. Further, the beam elements 53f to 56f and the beam elements 53r to 56r each represent a portion of the crown portion of the tooth 30.

[0064] In the simplified model 100, the node 33 corresponds to the boundary between the crown portion and the root of the tooth 30. Further, the node 34 corresponds to the end portion on the side far from the occlusal surface of the tooth root of the tooth 30. Similarly, the nodes 43 and 44 correspond to the respective portions of the tooth 40.

[0065] In the simplified model 100, the surrounding tissue 60 such as the alveolar bone surrounding the periphery of the tooth root of the tooth 30 is represented by the beam elements 36x, 36y, 36z and the beam elements 37x, 37y, 37z. The beam elements 36x, 36y, 36z correspond to the tissue on the side closer to the crown portion of the tooth 30 among the surrounding tissue 60 of the tooth 30. Further, the beam elements 37x, 37y, 37z correspond to the tissue on the side farther from the crown portion of the tooth 30 among the surrounding tissue 60 of the tooth 30. Similarly, the surrounding tissue 60 surrounding the periphery of the tooth root of the tooth 40 is also represented by the beam elements 46x, 46y, 46z and the beam elements 47x, 47y, 47z.

[0066] Each of the beam elements 36x, 36y, and 36z extends in the same directions as the X, Y, and Z axes of the reference coordinates of the simplified model. That is, the beam element 36x extends in the same direction as the X axis, the beam element 36y extends in the same direction as the Y axis, and the beam element 36z extends in the same direction as the Z axis. That is, the beam element 36x represents the characteristics of the surrounding tissue 60 of the tooth 30 in the X-axis direction, the beam element 36y represents the characteristics of the surrounding tissue 60 of the tooth 30 in the Y-axis direction, and further, the beam element 36z represents the characteristics of the surrounding tissue 60 of the tooth 30 in the Z-axis direction. The same applies to the beam elements 37x to 37z, the beam elements 46x to 46z, and the beam elements 47x to 47z. Hereinafter, the beam elements 36x to 36z are also collectively referred to as the beam portion 36. Similarly, the beam elements 37x to 37z, the beam elements 46x to 46z, and the beam elements 47x to 47z are also referred to as the beam portion 37, the beam portion 46, and the beam portion 47, respectively. In this way, since the surrounding tissue 60 is represented by a plurality of beam elements extending in the same directions as the X, Y, and Z axes of the reference coordinates of the simplified model, a model in which the characteristics of the surrounding tissue 60 are appropriately reflected is obtained.

[0067] The array calculation unit 12 represents the length of each beam element, in principle, by a length corresponding to the actual length of the corresponding portion. For example, in the simplified model 100, the beam elements 31a and 31b are represented by lengths corresponding to the actual lengths of the crown portion and the root portion of the tooth 30, respectively. On the other hand, the length of the beam element may be optimized (corrected) so that the actual characteristics of the corresponding portion are accurately reflected and appropriate analysis is performed. In addition, for the beam elements representing the surrounding tissue 60, lengths corresponding to the characteristics of the surrounding tissue 60 are set. For example, the lengths of the respective beam elements of the beam elements 36x, 36y, 36z and the beam elements 37x, 37y, 37z are set to lengths that appropriately represent the components in the reference axis directions (X, Y, Z directions) of the load generated when a correction force acts on the tooth 30.

[0068] In the simple model 100, characteristics corresponding to the physical properties of the corresponding parts are set for each beam element. These characteristics include the bending stiffness and torsional stiffness corresponding to the physical properties of the corresponding parts. For example, for the beam elements 51f to 52r representing the aligner part 50P, characteristics corresponding to the physical properties of the corresponding parts of each beam element of the aligner part 50P are set. Taking an example for explanation, for the beam element 51f, characteristics such as bending stiffness and torsional stiffness corresponding to the physical properties of the part of the aligner part 50P that covers the occlusal surface side of the outer surfaces of the teeth 30 and 40 are set. Similarly, for the beam elements 51r, 52f, and 52r, characteristics such as bending stiffness and torsional stiffness corresponding to the physical properties of the corresponding parts of the aligner part 50P for each beam element are set.

[0069] Similarly, for other beam elements, characteristics corresponding to the physical properties of the corresponding parts are set respectively. That is, since the beam elements 31a, 31b, 41a, 41b, and the beam elements 53f to 56r correspond to the parts of the rigid teeth 30 and 40, characteristics as a rigid body are set respectively. Also, for the beam elements 36x to 37z and the beam elements 46x to 47z, characteristics estimated from the features of the surrounding tissue 60, such as the shape of the alveolar bone, the distance between the teeth 30, 40 and the alveolar bone (such as the thickness of the periodontal ligament), and the bone density of the bone, are reflected. That is, the components in the reference axis direction of the characteristics of the surrounding tissue 60 obtained based on the tooth information are assigned and set to the corresponding beam elements.

[0070] <When an attachment is provided on a specific tooth> When an attachment for fixing an aligner is provided on a patient's tooth, the array calculation unit 12 sets the torsional rigidity of the beam element corresponding to each part of the aligner related to the tooth on which the attachment is provided to a value larger than that when the attachment is not provided. Here, each part of the aligner related to the tooth on which the attachment is provided is each part of the aligner that is mechanically affected by the presence of the attachment. For example, it is a part of the aligner that covers the space between the tooth on which the attachment is provided and the tooth adjacent to that tooth, or a part of the aligner within a certain length range from the tooth on which the attachment is provided.

[0071] When an attachment is provided on a patient's tooth, the corresponding part of the aligner fits into and is fixed to the attachment, making it difficult for the aligner to shift or twist. Therefore, when an attachment is provided on a patient's tooth, the array calculation unit 12 regards that a more torsion-resistant aligner than normal is worn on that part, and sets the torsional rigidity of the beam element corresponding to the part of the aligner related to that tooth to a large value. That is, a process is performed to set the torsional rigidity of the beam element to a value larger than that when the attachment is not provided. By performing such a process, the array calculation unit 12 reflects the characteristics due to the attachment in the simplified model by a simple method.

[0072] 5. Analysis process (simulation) using a simplified model Next, the analysis process using the simplified model performed by the movement calculation unit 13 will be described. As described above, when orthodontic treatment using an aligner is performed, the movement calculation unit 13 analyzes the forces applied to the patient's teeth respectively and calculates the movement of the patient's teeth during the orthodontic period. When performing this process, the movement calculation unit 13 applies the aforementioned orthodontic force calculation model and attenuation model to the simplified model respectively to perform the analysis process. Specifically described with reference to FIG. 6, the movement calculation unit 13 applies the orthodontic force calculation model to the beam elements corresponding to the aligner part 50P of the simplified model 100, and calculates the forces generated by each beam element based on the deformation ratios occurring in each part of the aligner part 50P to perform the analysis process. For example, the movement calculation unit 13 applies the orthodontic force calculation model to the beam element 51f of the simplified model 100 and calculates the orthodontic force generated in that part based on the deformation ratio of the corresponding part of the aligner part 50P. Similarly, for the beam elements 51r, 52f, 52r corresponding to the other parts of the aligner part 50P, the orthodontic force calculation model is applied to calculate the orthodontic forces generated by each part.

[0073] Also, the movement calculation unit 13 applies the attenuation model to each of the beam elements constituting the beam parts 36, 37, 46, 47 corresponding to the surrounding tissue 60 of the simplified model 100 to calculate the magnitude of the load generated by each beam element and perform the analysis process. For example, the movement calculation unit 13 applies the attenuation model to the beam elements 36x, 36y, 36z corresponding to the surrounding tissue 60 on the crown side of the tooth 30 to calculate the magnitude of the load generated by the beam elements 36x, 36y, 36z.

[0074] Then, the movement calculation unit 13 calculates the state of the simplified model 100 after a predetermined time has elapsed based on the angles formed by the respective beam elements, the lengths of the beam elements, their rotational moments, and the characteristics (bending stiffness and torsional stiffness) set for each beam element.

[0075] 6. Flow of the process Hereinafter, mainly with reference to FIGS. 7 to 11, the flow of processing by the simulation device 1 will be described. That is, the simulation method by the simulation device 1 will be described. Hereinafter, the aligner used for orthodontic treatment will be described as the aligner 80.

[0076] First, the information acquisition unit 11 acquires the dental information of the patient (S100) (dental information acquisition step). The information acquisition unit 11 may acquire the dental information from the data output from an X-ray CT device or the like according to a standard such as DICOM. Alternatively, the information acquisition unit 11 may acquire the dental information from the information directly communicated by the computer main body 10 with an X-ray CT device or the like. The three-dimensional information of the patient used for acquiring the dental information is not limited to the information from the X-ray CT device, and may be information from a device different from the X-ray CT device that acquires the three-dimensional information using light other than X-rays, for example. The information acquisition unit 11 stores the acquired dental information in the storage unit 2.

[0077] The information acquisition unit 11 acquires information about the patient, for example, by causing the display / output device 4 to display an input screen and requesting the user to input information. For example, information about the patient's bone density, information about the patient's age, and other information about the patient required for the analysis process are acquired. Information about the patient's bone may be calculated by other parts of the information acquisition unit 11 or the computer main body 10 based on the acquired image information of an X-ray CT device or the like. Alternatively, based on the patient's age, information about the bone density obtained by referring to a table in which the standard bone density stored in the storage unit 2 is associated with the age may be used. The information acquisition unit 11 stores the acquired information about the patient in the storage unit 2 as part of the dental information.

[0078] In addition, the information acquisition unit 11 requests the user to input information about the material of the aligner used for orthodontic treatment, and acquires information about the material of the aligner. The information acquisition unit 11 stores the acquired information about the material of the aligner in the storage unit 2 as part of the aligner information.

[0079] Furthermore, the information acquisition unit 11 reads out the tooth information stored in the storage unit 2 and converts it into STL information (S110). The information acquisition unit 11 stores the converted STL information in the storage unit 2.

[0080] Subsequently, according to the user's operation, a process of setting the ideal tooth alignment state after orthodontic treatment is performed. Specifically, the display signal output unit 14 displays the three-dimensional image before orthodontic treatment on the display / output device 4 based on the STL information (S120) (see FIG. 8). In FIG. 8, STL images of teeth 71 to 76, which are the upper jaw teeth of the patient before orthodontic treatment, are shown. Note that in FIG. 8, the surrounding tissues surrounding the root portions of each of the teeth 71 to 76 are not shown.

[0081] While checking the three-dimensional image before orthodontic treatment displayed on the display / output device 4, the user operates the input device 3 such as a mouse to set the position and posture of the teeth to be corrected. The array calculation unit 12 creates information indicating the ideal tooth alignment state set according to the user's operation (S130). The display signal output unit 14 creates a three-dimensional image showing the ideal tooth alignment based on the created information and displays it on the display / output device 4 (see FIG. 9). FIG. 9 exemplifies a three-dimensional image of the ideal arrangement set by the user. Teeth 71i to 76i in FIG. 9 respectively correspond to teeth 71 to 76 in FIG. 8. In FIG. 8, tooth 73 is the tooth to be corrected, and FIG. 9 shows the ideal arrangement state in which tooth 73 in FIG. 8 has been moved to the gap between tooth 72 and tooth 74.

[0082] The three-dimensional image of the ideal arrangement set by the user may be displayed superimposed (overlaid) on the three-dimensional image before orthodontic treatment. Alternatively, it may be displayed in a region different from the three-dimensional image before orthodontic treatment.

[0083] When the ideal tooth alignment state is set by the user, the array calculation unit 12 creates aligner information of the aligner 80 used for the patient's orthodontic treatment.

[0084] Specifically, the arrangement calculation unit 12 generates information regarding the dimensions of each part of the aligner 80, which is necessary when creating a simple model based on the tooth information. Further, the arrangement calculation unit 12 creates, as aligner information, the deformation ratio (deformation amount) of the aligner 80 during orthodontic treatment based on the information indicating the ideal tooth arrangement state set by the user and the information indicating the tooth arrangement state before orthodontic treatment.

[0085] The arrangement calculation unit 12 calculates the overall magnitude of the orthodontic force acting on the teeth to be corrected by the aligner 80 used in the orthodontic treatment during the orthodontic treatment. Specifically, based on the orthodontic movement distance and the information regarding the physical properties of the material of the aligner 80, the arrangement calculation unit 12 calculates the magnitude of the orthodontic force applied to the teeth during the orthodontic treatment by the aligner 80 used in the orthodontic treatment.

[0086] The arrangement calculation unit 12 generates aligner information by associating the information regarding the dimensions of the aligner 80 and the information regarding the material (raw material) of the aligner 80 respectively (aligner information creation step). The arrangement calculation unit 12 stores the aligner information and the information regarding the calculated overall magnitude of the orthodontic force in the storage unit 2.

[0087] Subsequently, the analysis process when the aligner is worn is performed (movement calculation step). First, the aligner information is read (S150) (aligner information read / update step). Specifically, the arrangement calculation unit 12 refers to the storage unit 2 and reads the aligner information of the aligner 80. The arrangement calculation unit 12 also reads the STL information of the teeth before orthodontic treatment together.

[0088] Based on the read aligner information, the tooth STL information, and the tooth information, the array calculation unit 12 generates a simplified model 200 (see FIG. 10). Specifically, a simplified model 200 is created (S160) (simplified model creation step) in which the patient's teeth 71 to 76, the respective surrounding tissues of the teeth 71 to 76, and the respective parts of the aligner 80 are replaced with beam elements having corresponding lengths. In FIG. 10, the tooth 71 is represented by a beam portion 71A in which a beam element 71a and a beam element 71b are linearly connected. Similarly, the teeth 72 to 76 are also represented by beam portions 72A to 76A. In FIG. 10, the beam portions 71A to 76A are represented by thick two-dot chain lines.

[0089] Among the aligners 80 used for orthodontic treatment, the portion covering the section between the tooth 71 and the tooth 72 is represented by a beam portion 81A composed of four beam elements 811f, 811r, 812f, and 812r. Similarly, the portion covering the section between the tooth 72 and the tooth 73 of the aligner 80 is represented by a beam portion 82A composed of four beam elements. The portions of the aligner 80 covering the respective sections between the tooth 73 and the tooth 74, between the tooth 74 and the tooth 75, and between the tooth 75 and the tooth 76 are also represented by beam portions 83A, 84A, and 85A. In FIG. 10, the beam portions 83A, 84A, and 85A are represented by thick dashed lines.

[0090] The surrounding tissues of the tooth 71 are represented by beam portions 61a and 61b composed of three beam elements extending in the same directions as the XYZ axes respectively. Similarly, the respective surrounding tissues of the teeth 72 to 76 are also represented by beam portions 62a to 66b. In FIG. 10, the beam portions 61a to 66b are shown by thin solid lines.

[0091] Subsequently, the movement calculation unit 13 applies a correction force calculation model to each beam element constituting the beam parts 81A to 85A corresponding to the aligner 80, and calculates the correction forces generated in the beam parts 81A to 85A (correction force calculation step) (S170). Note that the movement calculation unit 13 selects a correction force calculation model corresponding to the material (material quality) of the aligner 80 input by the user, and calculates each correction force. The movement calculation unit 13 associates the calculated correction forces with the corresponding beam elements respectively, and stores them in the storage unit 2 as correction force data.

[0092] Based on the tooth information and the attenuation model, the movement calculation unit 13 sets the characteristics corresponding to the surrounding tissue for each beam element corresponding to the surrounding tissue of the tooth (physical property parameter setting step) (S180). Taking the surrounding tissue of the tooth 71 as an example, the movement calculation unit 13 assigns, according to the direction, the characteristics as the load possessed by the surrounding tissue to each beam element constituting the beam parts 61a and 61b based on the attenuation model. Similarly for the surrounding tissues of the other teeth 72 to 76, the movement calculation unit 13 assigns the corresponding characteristics to each beam element constituting each of the beam parts 62a to 66b based on the tooth information and the attenuation model. Note that the movement calculation unit 13 selects an attenuation model corresponding to the information about the patient (such as bone density and age) input by the user, and sets it for the beam elements corresponding to the surrounding tissue.

[0093] Based on the aligner information, the movement calculation unit 13 sets the bending rigidity and torsional rigidity corresponding to the physical properties of the corresponding part of the corresponding aligner 80 for each beam element constituting the beam parts 81A to 85A.

[0094] The movement calculation unit 13 calculates the magnitude and direction of the forces and loads generated in each part of the simplified model 200, and also calculates the time change of each of them (simulation step) (S190). Based on the calculated results, the movement calculation unit 13 performs a process of changing the information regarding the position and orientation of each beam element after a certain period of time has elapsed. That is, the movement calculation unit 13 calculates the arrangement state of the beam parts 71A to 76A after a certain period of time has elapsed.

[0095] When the movement calculation unit 13 determines that a predetermined time has elapsed and the correction by the aligner 80 has ended, it causes the storage unit 2 to store the information of the simple model 200 at that time. The display signal output unit 14 generates a three-dimensional image showing the arrangement state of the teeth 71 to 76 based on the information of the simple model 200 on which the movement calculation unit 13 has performed the analysis process, and displays it on the display / output device 4 as a three-dimensional image showing the simulation result after correction (S200) (see FIG. 11).

[0096] FIG. 11 shows a three-dimensional image of the teeth 71s to 76s, which is the simulation result. The teeth 71s to 76s in FIG. 11 respectively correspond to the teeth 71 to 76 in FIG. 8. The three-dimensional image showing the simulation result may be displayed superimposed on the three-dimensional image of the ideal tooth arrangement so that the difference from the three-dimensional image of the ideal tooth arrangement set by the user can be understood. Alternatively, it may be displayed in a region different from the three-dimensional image of the ideal tooth arrangement. Or, it may be displayed superimposed on the three-dimensional image before the orthodontic treatment so that it can be compared with the state before the orthodontic treatment. Alternatively, it may be displayed in a region different from the three-dimensional image of the ideal state before the orthodontic treatment.

[0097] 7. Explanation of the effect In the simulation device 1 configured as described above, the movement calculation unit 13 performs a process of calculating the arrangement state of each tooth based on the tooth information and the aligner information. For this reason, analysis processing is performed based on the teeth of the patient, the state of the surrounding tissues thereof, and the characteristics of the aligner used for orthodontic treatment. In other words, it is possible to predict the effect of orthodontic treatment considering the state of the patient and the characteristics of the aligner. Further, the movement calculation unit 13 calculates, using a damping model, the magnitude of the load received by the patient's teeth from the surrounding tissues during orthodontic treatment. Since this damping model is a simple mathematical model, it is not necessary to perform complex arithmetic processing compared to conventional simulations. That is, in the simulation by the simulation device 1 of the present disclosure, the required arithmetic processing ability is reduced compared to the prior art. For this reason, accurate analysis processing that appropriately reflects the characteristics of the surrounding tissues of the patient's teeth can be performed without performing complex analysis processing such as that of a conventional simulation device. That is, it is possible to accurately predict the movement of the teeth and the arrangement state of the teeth after orthodontic treatment when orthodontic treatment of the patient's teeth is performed using an aligner without performing complex analysis processing. The dedicated program of the simulation device 1 and the simulation method by the simulation device 1 have the same effects.

[0098] This damping model is a mathematical model based on the creep phenomenon of a predetermined substance. For this reason, accurate analysis processing that appropriately reflects the characteristics of the surrounding tissues in actual orthodontic treatment can be performed without performing complex arithmetic processing.

[0099] Further, in the simulation device 1 of the present disclosure, analysis processing is performed using a simple model in which each part of the teeth, the surrounding tissues of the teeth, and the aligner is represented by a plurality of beam elements. Each beam element is set with bending characteristics and torsional characteristics corresponding to the physical properties of the corresponding part.

[0100] Therefore, during orthodontic treatment, the forces acting on the teeth, their surrounding tissues, and each part of the aligner, as well as their movements, can be analyzed by performing simple arithmetic operations. That is, accurate analysis processing can be performed at a processing speed improved from that of conventional simulations, taking into account the morphological and physical characteristics of each part.

[0101] Also, as shown in the above embodiment, for example, by representing a patient's teeth with two beam elements corresponding to the crown part and the root part of each tooth, the clinical characteristics of the teeth can be reflected in the simplified model. Further, the aligner can be divided for each region where it is disposed, and the aligner can be represented using beam elements corresponding to each region. In this way, when orthodontic treatment is being performed, a simplified model can be obtained that takes into account the size (area) of each region and the difference in the forces acting on each region.

[0102] That is, by performing analysis processing using the simplified model configured as described above, an accurate simulation can be performed taking into account the different characteristics of each part of the teeth, the surrounding tissues of the teeth, and the aligner, the size of each part, and the difference in the forces acting on each part.

[0103] Furthermore, when an attachment is provided on a predetermined tooth, the torsional rigidity of the beam element corresponding to the aligner related to the tooth on which the attachment is provided is set to a value larger than that when no attachment is provided. That is, the analysis processing is performed on the assumption that a part of the aligner with a torsional rigidity larger than normal is disposed in the part related to the tooth on which the attachment is provided. Therefore, it is not necessary to perform additional processing due to the provision of the attachment, and the analysis processing can be performed by the same process as in the normal case (when there is no attachment).

[0104] Note that the technical scope of the present disclosure is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present disclosure. Furthermore, the present disclosure only needs to conform to the gist of the disclosure described in the above embodiments, and is not limited to the above embodiments. Therefore, a configuration in which at least two of the above-described multiple embodiments are combined, or a configuration in which any one of the constituent elements illustrated or described with reference numerals in the above embodiments is abolished may also be acceptable.

Explanation of Reference Numerals

[0105] 1…Simulation device 2…Storage unit 3…Input device 4…Display / output device 5…CPU 6…Memory 7…Interface unit 10…Computer main body 11…Information acquisition unit 12…Array calculation unit 13…Movement calculation unit 14…Display signal output unit 20, 100, 200…Simple models 30, 40, 71 to 76…Teeth 50…Aligner 50P…Aligner part 60…Surrounding tissue 30A, 40A, 71A to 76A, 81A to 85A, 91 to 95…Beam parts

Claims

1. A simulation device for predicting movement of a patient's teeth when orthodontic treatment of the patient's teeth is performed using aligners, comprising: a movement calculation unit that calculates an arrangement state indicating a position and a posture of a predetermined tooth after orthodontic treatment based on tooth information including at least information on the shape of each of the teeth of the patient, information indicating the arrangement state of the teeth of the patient before the orthodontic treatment is performed, and information on the tissues surrounding the teeth of the patient, and aligner information including at least information on the shape and physical properties of the aligner, the movement calculation unit calculates the positioning state based on an orthodontic force applied to the specific tooth by the aligner and a magnitude of a load generated by tissue surrounding the specific tooth when the orthodontic force is applied to the specific tooth, the movement calculation unit calculates the magnitude of the load using a damping model in which the load damps over time according to a predetermined characteristic, to calculate the placement state; Simulation device.

2. The damping model is a mathematical model based on the creep phenomenon of a given material. The simulation device according to claim 1 .

3. The movement calculation unit performs the following steps based on the tooth information and the aligner information: The positioning state is calculated using a simplified model in which the aligner, the patient's teeth, and tissues surrounding the teeth are each represented using a plurality of beam elements having a beam-like shape; Each of the beam elements constituting the simplified model corresponds to a part of either the aligner, the tooth, or the tissue surrounding the tooth, The movement calculation unit calculates the arrangement state assuming that each of the beam elements has bending rigidity and torsional rigidity corresponding to physical properties of the corresponding part. The simulation device according to claim 1 or 2.

4. The movement calculation unit is When the tooth is provided with an attachment used in the orthodontic treatment, the torsional stiffness of the beam element corresponding to the portion of the aligner related to the tooth provided with the attachment is set to a value greater than that when the tooth is not provided with the attachment, and the positioning state is calculated. The simulation device according to claim 3.

5. A program for operating an electronic computing device as a simulation device for predicting the movement of a patient's teeth when orthodontic treatment of the patient's teeth is performed using aligners, the program comprising: The electronic computing device, a movement calculation unit that calculates an arrangement state indicating a position and a posture of a predetermined tooth after orthodontic treatment based on tooth information including at least information on the shape of each of the teeth of the patient, information indicating the arrangement state of the teeth of the patient before the orthodontic treatment is performed, and information on the tissues surrounding the teeth of the patient, and aligner information including at least information on the shape and physical properties of the aligner, the movement calculation unit calculates the positioning state based on an orthodontic force applied to the specific tooth by the aligner and a magnitude of a load generated by tissue surrounding the specific tooth when the orthodontic force is applied to the specific tooth, the movement calculation unit calculates the magnitude of the load using a damping model in which the load damps over time according to a predetermined characteristic, to calculate the placement state; A program that operates as a simulation device.

6. 1. A simulation method for predicting tooth movement of a patient during orthodontic treatment of the patient's teeth using aligners, using an electronic computing device, comprising: a movement calculation step in which an electronic computing device calculates an arrangement state indicating an arrangement position and posture of a specific tooth after orthodontic treatment based on tooth information including at least information on the shape of each of the patient's teeth, information indicating the arrangement state of the patient's teeth before the orthodontic treatment is performed, and information on the tissues surrounding the patient's teeth, and aligner information including at least information on the shape and physical properties of the aligner; The movement calculation step is a step of calculating the positioning state based on the orthodontic force applied to the predetermined tooth by the aligner and the magnitude of the load generated by the tissue surrounding the predetermined tooth when the orthodontic force is applied to the predetermined tooth, In the movement calculation step, the magnitude of the load is calculated using a damping model in which the load damps over time according to a predetermined characteristic, and the placement state is calculated. Simulation method.

Images