Oral orthodontic effect prediction method and optimal orthodontic scheme determination method

Abstract

The application belongs to the technical field of orthodontics, and provides an orthodontic effect prediction method and an optimal orthodontic scheme determination method, which are used for predicting the orthodontic effect of wearing an orthodontic device and determining an optimal orthodontic scheme. The orthodontic effect prediction method comprises the following steps: determining a target dental arch digital model based on an initial dental arch digital model; determining an orthodontic device digital model based on the initial dental arch digital model and the target dental arch digital model; simulating the wearing of the orthodontic device and the orthodontic process based on the initial dental arch digital model, the orthodontic device digital model and an orthodontic parameter combination, and obtaining a predicted dental arch digital model. The technical scheme of the application can accurately predict the orthodontic effect of the orthodontic device and determine an optimal orthodontic scheme according to the orthodontic effects corresponding to multiple orthodontic parameter combinations.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of orthodontics, further relates to a method for digitally simulating the orthodontic effect of an orthodontic appliance, and specifically provides an orthodontic effect prediction method and an optimal orthodontic scheme determination method. BACKGROUND

[0002] In recent years, more and more orthodontic appliances for treating various types of dental deformities are designed and manufactured using digital methods. Accordingly, in order to ensure that the designed and manufactured orthodontic appliances can achieve the desired orthodontic effect, it is necessary to predict their use effect during the design stage and evaluate whether the design is reasonable or whether further optimization is needed based on the prediction results.

[0003] In recent years, various methods for verifying the orthodontic effect of orthodontic appliances using digital simulation technology have been proposed. For example, patent 200580013846.4 proposes a design and manufacturing method for a shell-shaped appliance for aligning teeth, which uses a digital model of teeth to design a digital model of the shell-shaped appliance, and obtains the movement of the tooth roots after wearing the shell-shaped appliance through finite element simulation. Patent 201380007617.X determines one or more forces applied to the teeth by virtually placing a dental appliance on a set of virtual teeth.

[0004] The above-mentioned orthodontic effect simulation methods are mainly aimed at the use of shell-shaped appliances, which are also known as invisible aligners. They are made of relatively hard resin materials and are mainly used to apply corrective forces to the upper or lower dental arches to align the teeth. During the wearing and orthodontic process, the influence of the different occlusal relationships and forces on the alignment of the dental arches does not need to be considered. However, for occlusal induction appliances with combined orthodontic functions such as "aligning teeth-expanding dental arches-adjusting occlusal relationship", the simulation method that only considers the application of corrective forces by the appliance cannot accurately predict the orthodontic effect.

[0005] Therefore, a prediction method is needed that can comprehensively consider the effects of various factors during the wearing and orthodontic process of the orthodontic appliance on the orthodontic effect, in order to more accurately predict the orthodontic effect and select the appropriate orthodontic scheme or optimize the design of the orthodontic appliance based on the prediction results. SUMMARY

[0006] The purpose of the present application is to solve the problems existing in the prior art and provide an orthodontic effect prediction method for appliances with combined orthodontic functions.

[0007] The embodiments of the present application can be implemented by the following technical solutions:

[0008] An aspect of the present application provides an orthodontic effect prediction method for predicting the orthodontic effect of a dental arch wearing an orthodontic device, comprising the following steps:

[0009] S1: obtaining an initial dental arch digital model and a target dental arch digital model;

[0010] S2: obtaining an orthodontic device digital model;

[0011] S3: simulating the wearing of the orthodontic device and the orthodontic process based on the initial dental arch digital model, the orthodontic device digital model, and an orthodontic parameter combination to obtain a predicted dental arch digital model.

[0012] Further, the initial dental arch digital model is generated based on the actual morphology of the upper and lower jaws before the start of the orthodontic period and the actual occlusal relationship of the upper and lower jaws; the target dental arch digital model is generated based on the target morphology of the upper and lower jaws and the target occlusal relationship of the upper and lower jaws expected to be achieved at the end of the orthodontic period determined by the orthodontic prescription; and the predicted dental arch digital model is generated based on the predicted morphology of the upper and lower jaws and the predicted occlusal relationship of the upper and lower jaws at the end of the orthodontic period predicted by simulating the wearing of the orthodontic device and the orthodontic process.

[0013] Further, the initial dental arch digital model, the predicted dental arch digital model, and the target dental arch digital model can all have relative movement of the upper and lower jaws according to the corresponding occlusal relationship.

[0014] Further, the occlusal relationship includes the movement parameters of the condyle in the occlusal process.

[0015] Further, the movement parameters of the condyle in the occlusal process include the movement trajectory inclination angle and / or the movement trajectory curve of the condyle in the occlusal process.

[0016] Preferably, the actual occlusal relationship is automatically obtained by measuring the dental arch to be corrected using a jaw frame.

[0017] Preferably, the orthodontic parameter combination includes one or more of the following parameters: occlusal force of wearing the orthodontic device, duration of each wearing of the orthodontic device, number of times of wearing the orthodontic device per day, and total number of days of the orthodontic period.

[0018] Preferably, the occlusal force of wearing the orthodontic device is obtained by a force sensor arranged on the initial dental arch digital model.

[0019] Preferably, the simulation of the wearing of the orthodontic device and the orthodontic process in step S3 includes simulating at least one wearing process of the orthodontic device and at least one orthodontic process during the period from wearing to removing.

[0020] Further, step S3 includes the following steps:

[0021] S31: taking the initial dental arch digital model as a current dental arch digital model;

[0022] S32: simulating a wearing process of the current appliance based on the current dental arch digital model, the appliance digital model and the orthodontic parameters to determine an orthodontic force distribution of the current dental arch digital model after wearing the appliance;

[0023] S33: simulating an orthodontic process of the current wearing appliance based on the orthodontic force distribution and the orthodontic parameter combination to obtain an intermediate dental arch digital model after the current orthodontic process;

[0024] S34: determining whether the orthodontic period is over, if the determination result is yes, taking the intermediate dental arch digital model as a predicted dental arch digital model and ending the simulation, if the determination result is no, taking the intermediate dental arch digital model as a new current dental arch digital model and returning to step S32.

[0025] Further, the orthodontic force includes at least one of the following: a force on at least one tooth, a force on the upper jaw and / or the lower jaw, a traction force on the condyle.

[0026] Preferably, the simulation is performed by a nonlinear finite element calculation method.

[0027] Further, simulating the wearing process includes setting one or more of the following forced loading conditions: a forced velocity condition, a forced displacement condition, a forced rotation condition.

[0028] Preferably, the forced velocity condition is 0.001 m / s to 3 m / s; and simulating the wearing process further includes setting a damping parameter.

[0029] Another aspect of the present application provides a method for determining an optimal orthodontic scheme, which uses the oral orthodontic effect prediction method to obtain and evaluate the oral orthodontic effects corresponding to a plurality of orthodontic parameter combinations to determine an optimal orthodontic scheme, including the following steps:

[0030] A1: performing the steps S1 and S2 to obtain the initial dental arch digital model, the target dental arch digital model and the appliance digital model;

[0031] A2: establishing a search grid of orthodontic parameters to obtain a plurality of orthodontic parameter combinations corresponding to each search grid point;

[0032] A3: traversing the search grid, using each orthodontic parameter combination to simulate the wearing and orthodontic processes of the appliance by the step S3 to obtain a plurality of predicted dental arch digital models corresponding to each orthodontic parameter combination;

[0033] A4: evaluating the orthodontic effect corresponding to each group of orthodontic parameter combinations based on the target dental arch digital model and each predicted dental arch digital model, and determining the optimal orthodontic scheme or optimizing the digital model of the appliance according to the evaluation result.

[0034] Further, step A4 comprises the following steps:

[0035] A41: determining the deviation function corresponding to each group of orthodontic parameter combinations based on the deviation of each predicted dental arch digital model and the target dental arch digital model;

[0036] A42: determining the number N of deviation functions less than the deviation threshold value;

[0037] A43: if N=0, optimizing the digital model of the appliance, if N=1, selecting the group of orthodontic parameter combinations corresponding to the deviation function to formulate the optimal orthodontic scheme, and if N≥2, formulating multiple orthodontic schemes based on multiple groups of orthodontic parameter combinations corresponding to multiple deviation functions, and selecting the optimal orthodontic scheme therefrom.

[0038] Further, the deviation function is generated based on at least one of the following values: the pose difference value of at least one tooth to be corrected on the predicted dental arch digital model and the target dental arch digital model, the difference value of the dental arch form parameter of the predicted dental arch digital model and the dental arch form parameter of the target dental arch digital model, and the difference value of the occlusal relationship of the predicted dental arch digital model and the occlusal relationship of the target dental arch digital model.

[0039] The embodiment of the present application provides an orthodontic effect prediction method, which has at least the following beneficial effects:

[0040] (1) The technical scheme provided by the present application is aimed at the combined correction mechanism of occlusal induction appliance, extracts multiple parameters affecting the orthodontic effect to establish a multi-dimensional parameter search grid, determines the optimal orthodontic scheme or optimizes the appliance design based on the comprehensive evaluation of the multi-parameter cost function, and can effectively improve the accuracy of the simulation result, providing quantitative data reference for determining the orthodontic scheme and optimizing the appliance design.

[0041] (2) The technical scheme provided by the present application changes the existing orthodontic appliance correction effect simulation method which only performs static and linear finite element simulation on the orthodontic effect after the appliance is worn, considers the influence of the appliance wearing process on the orthodontic effect, uses a dynamic and nonlinear finite element calculation method to calculate the wearing state of the dental arch and the appliance and the distribution of the orthodontic force at the end of the wearing process, and further simulates the orthodontic process of the appliance on this basis, which can make the simulation process closer to the actual wearing and orthodontic process, thereby greatly increasing the credibility of the simulation result.

[0042] (3) The technical solution of the present application uses a dental arch digital model capable of moving according to the occlusion relationship to simulate the wearing process of the appliance, and abstracts different occlusion processes of the upper and lower jaws, such as opening and closing movement, forward and backward movement, and side occlusion movement, into condylar movement trajectory parameters, so that the relative movement of the upper and lower jaws during simulation of the wearing process of the appliance is truly reproduced, thereby improving the accuracy of the finite element simulation results. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is a perspective view of an existing shell-shaped appliance;

[0044] Figure 2A is a perspective view of an existing occlusion-inducing appliance;

[0045] Figure 2B is a rear view of an existing occlusion-inducing appliance;

[0046] Figure 2C is a top view of an existing occlusion-inducing appliance;

[0047] Figure 2D is a C-C sectional view of the occlusion-inducing appliance in Figure 2C

[0048] Figure 2E is a D-D sectional view of the occlusion-inducing appliance in Figure 2C

[0049] Figure 3A , Figure 3B respectively show different wearing effects achieved by wearing through different occlusion processes;

[0050] Figure 4 is an occlusion force curve when the upper and lower jaws perform various types of occlusion movements;

[0051] Figure 5 is a flowchart of an orthodontic effect prediction method according to an embodiment of the present application;

[0052] Figure 6 is a schematic view of the upper and lower jaws connected by the temporomandibular joint;

[0053] Figures 7A to 7D is various movement forms of the lower jaw;

[0054] Figure 8 is a schematic view of a specific jaw frame and its use state;

[0055] Figure 9 is a specific implementation process for obtaining an actual occlusion relationship through a jaw frame;

[0056] ​​Figures 10A to 10C a schematic diagram for dynamically reproducing the opening and closing process for an initial dental model according to an embodiment of the present application;

[0057] Figure 11 a flowchart for step S3 according to an embodiment of the present application;

[0058] Figure 12 a specific step for simulating the wearing process of an appliance according to an embodiment of the present application;

[0059] Figure 13 a comparison of structural oscillation of an appliance digital model before and after adding mass damping according to an embodiment of the present application;

[0060] Figures 14A to 14C a schematic diagram for simulating a specific wearing process according to an embodiment of the present application;

[0061] Figures 15A to 15C a change of orthodontic force on the initial dental model at each stage of the wearing process obtained by simulating a specific wearing process according to an embodiment of the present application;

[0062] Figure 16 a flowchart for the optimal orthodontic scheme determination method according to an embodiment of the present application. DETAILED DESCRIPTION

[0063] Hereinafter, the present application will be further described based on preferred embodiments and with reference to the accompanying drawings.

[0064] In addition, various components on the drawings are enlarged (thick) or reduced (thin) for convenience of understanding, but such practice is not intended to limit the scope of protection of the present application.

[0065] The singular form also includes the plural meaning, and vice versa.

[0066] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "inner", "outer" and the like indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the embodiments of the present application is usually placed, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, in the description of the present application, in order to distinguish different units, the first, second and the like are used in the specification, but these are not limited by the order of manufacture, and cannot be understood as indicating or implying relative importance, and the name may be different in the detailed description and the claims of the present application.

[0067] The terms in the specification are used to describe the embodiments of the present application, but are not intended to limit the present application. It should also be noted that, unless otherwise explicitly specified and limited, if the terms "arranged", "connected", "connected" appear, they should be understood broadly, for example, they can be fixedly connected, or detachably connected, or integrally connected; they can be mechanically connected, or directly connected, or indirectly connected through an intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood specifically.

[0068] In order to better illustrate the technical solutions of the present application, first, the orthodontic mechanism of different types of appliances for orthodontic treatment is described.

[0069] Figure 1 A shell-shaped appliance (also known as a clear aligner) for aligning teeth is shown, which is mainly used to correct the problems of tooth lip, tongue, twist and other posture irregularities. As shown in Figure 1 The shell-shaped appliance 100 has a plurality of tooth-containing shells 101, and the inner wall of each shell 101 forms a cavity 102 with the same shape as the crown part of the corresponding tooth. The plurality of shells are arranged according to the ideal posture of the corresponding teeth to form a U-shaped tooth groove. The manufacturing material of the above-mentioned shell-shaped appliance 100 is generally a resin material with certain hardness and elasticity. When it is worn on the teeth that need to be corrected, due to the difference between the posture of part (or all) of the teeth and the ideal posture, the part / or all of the shells will deform and generate a springback force to restore their original shape. The above-mentioned springback force acts on the teeth with irregular posture, which will gradually drive the teeth to move towards the ideal posture, thereby achieving the effect of correcting the misaligned teeth.

[0070] The stress and movement of the teeth after the shell-shaped appliance is worn on the teeth are calculated and simulated, which can predict and evaluate the orthodontic effect in advance, or further optimize the shape and structure. At present, there are many methods for finite element simulation of the orthodontic effect of the shell-shaped appliance, and the implementation ideas are roughly as follows: first, the finite element models of the shell-shaped appliance and the teeth are established respectively, then they are assembled together, and finally the stress and movement of the teeth are obtained through finite element calculation.

[0071] Figure 2A Another orthodontic appliance is shown in a perspective view, which is generally referred to as a bite-induced appliance, Figure 2B , Figure 2C , Figure 2D , Figure 2E are respectively the sectional views in the C-C direction and the D-D direction. As Figures 2A to 2EAs shown, the bite-inducing appliance 200 is composed of an outer wall 210 and an inner wall 220 in a substantially U-shape, and a bite pad 230 connected between the outer wall 210 and the inner wall 220. Further, the outer wall 210 can be subdivided into an outer wall upper portion 211 and an outer wall lower portion 212, and the inner wall 220 can be subdivided into an inner wall upper portion 221 and an inner wall lower portion 222. The inner surface of the outer wall upper portion 211, the inner surface of the inner wall upper portion 221, and the upper surface of the bite pad 230 form an upper tooth groove 240 for accommodating the upper dental arch. The inner surface of the outer wall lower portion 212, the inner surface of the inner wall lower portion 222, and the lower surface of the bite pad 230 form a lower tooth groove 250 for accommodating the lower dental arch.

[0072] Figures 2A to 2E The bite-inducing appliance is used to correct multiple dental malformations simultaneously, such as correcting the malposition of deciduous teeth, the malposition of permanent teeth, the crowding of the dental arch, and the malocclusion of the upper and lower jaws in children in the mixed dentition stage. The causes of the above problems include, but are not limited to, the malposition of tooth eruption, the insufficient width of the dental arch due to the delayed development of the dental and jaw bones, and the incorrect position and force habit of the muscle tissue due to the bad habits of the oral cavity. Obviously, a shell-shaped appliance for aligning the teeth cannot be applied to such a complex orthodontic operation.

[0073] As shown in Figures 2A to 2E The shape of the bite-inducing appliance 200 is designed to apply an aligning force to the teeth to guide the alignment of the teeth, to apply an expansion force to the upper and lower jaws to expand the dental arch, and to pull the temporomandibular joint and the nearby muscles to adjust the occlusal relationship of the upper and lower jaws. Specifically, as shown in Figures 2C to 2E The inner surfaces of the labial and lingual sides of the tooth groove are designed to match the crown surfaces of the aligned teeth, thereby guiding the teeth to move slightly to align; they extend along the mesial and distal directions according to the dental arch curve expected to be achieved during the treatment (as shown by the dashed line in Figure 2C Meanwhile, by adjusting the thickness, inclination angle, and other parameters of the bite pad at different positions, the relative positional relationship between the upper and lower tooth grooves is set according to the occlusal relationship of the upper and lower jaws expected during the treatment.

[0074] The manufacturing material of the bite-inducing appliance is generally soft medical silicone or the like, which is easy to deform under stress and has a smaller elastic force compared with resin materials, thereby being able to apply force to the soft tissues of the gums, jaws, and different parts of the oral cavity more gently.

[0075] Similar to shell-type orthodontic appliances, after designing the digital model of the aforementioned occlusal guiding orthodontic appliance, finite element simulation can be used to predict its achievable orthodontic effect or further optimize the appliance design. However, existing finite element simulation methods for shell-type orthodontic appliances are not suitable for simulating and calculating the orthodontic effect of the aforementioned occlusal guiding orthodontic appliance. This is because the complexity of simulating the orthodontic effect of occlusal guiding orthodontic appliances is far greater than that of shell-type orthodontic appliances.

[0076] (1) Most existing finite element simulation methods for the orthodontic effect of shell-shaped orthodontic appliances focus on calculating the orthodontic force and corresponding displacement of the teeth after wearing. The reason is that the finite element model of the teeth is generally set as a rigid body, while the finite element model of the shell-shaped orthodontic appliance is generally set as an elastic body with a large elastic modulus. After the appliance is assembled, it undergoes overall deformation. Moreover, the relative positional relationship between the dentition and the shell-shaped orthodontic appliance is independent of the wearing process. Therefore, the process of assembling the appliance into the dentition is generally simplified to an ideal situation. For example, during the assembly process, all degrees of freedom of the orthodontic appliance model at selected nodes and all degrees of freedom of the orthodontic appliance model in other selected nodes except for the wearing direction are restricted. Alternatively, several nodes are randomly selected at each tooth shape of the orthodontic appliance model and set as rigid connections.

[0077] (2) Unlike shell-shaped orthodontic appliances, bite-inducing orthodontic appliances accommodate both the upper and lower jaws and are generally made of soft medical silicone or other materials. Therefore, different wearing processes will produce significantly different wearing effects and further affect the orthodontic process after wearing.

[0078] For example, like Figure 3A and Figure 3B As shown, during the wearing of the occlusal guiding appliance 200, when the mandible 320 bites at different angles relative to the maxilla 310, the position of the mandibular dentition entering the lower alveolar 250 will be significantly different, which will cause the soft occlusal guiding appliance to undergo different degrees of morphological changes, resulting in a great difference in the distribution of orthodontic forces applied by the occlusal guiding appliance 200 to various parts of the dentition after wearing.

[0079] For example, Figure 4A specific upper and lower jaw occlusion force change curve is shown when the occlusion is performed. In daily life, the occlusion force generated by normal chewing is between 10-25 kg, the conscious occlusion force is 25-75 kg, and the night grinding is the unconscious occlusion, and the human body cannot effectively adjust the muscle force, so the night grinding occlusion force can reach more than 100 kg, which is greater than the conscious occlusion force during the day. Obviously, when the occlusion induction appliance is worn, the occlusion force generated by the upper and lower jaws is different in different stages and states, and the difference in the above occlusion force will also lead to different deformations of the occlusion induction appliance and different orthodontic forces on each part of the teeth and jaws.

[0080] Through the above analysis, it can be seen that in order to accurately simulate the wearing and orthodontic process of the occlusion induction appliance and the appliance with similar functions, the existing finite element simulation method needs to be improved to make the simulation results more consistent with the real wearing and orthodontic situation.

[0081] To solve the problems existing in the prior art, the embodiments of the present application provide an orthodontic effect prediction method and a computer device, Figure 5 The flow chart of the orthodontic effect prediction method according to the embodiments of the present application is shown, as Figure 5 The orthodontic effect prediction method includes the following steps:

[0082] S1: obtaining an initial dental arch digital model and a target dental arch digital model;

[0083] S2: obtaining an appliance digital model;

[0084] S3: simulating the wearing and orthodontic process of the appliance based on the initial dental arch digital model, the appliance digital model and the orthodontic parameter combination to obtain a predicted dental arch digital model.

[0085] The provided orthodontic effect prediction method of the present application determines a digital model of a target dental arch to be achieved by orthodontic treatment based on an initial dental arch digital model, and determines a digital model of an orthodontic appliance used for orthodontic treatment based on the initial dental arch digital model and the target dental arch digital model, then simulates the process of wearing the orthodontic appliance on the dental arch and the orthodontic process after wearing the orthodontic appliance by using a preset orthodontic parameter combination, and obtains a predicted dental arch digital model through simulation. The predicted dental arch digital model can be directly used as the prediction result of the orthodontic effect, and in some preferred embodiments, a quantitative orthodontic effect of the orthodontic effect can also be obtained based on the difference between the target dental arch digital model and the predicted dental arch digital model (the difference can include the difference in the arrangement state of the upper and lower dental arches, the difference in the shape of the upper and lower jaws, the difference in the occlusal relationship of the upper and lower jaws, etc.). The method changes the existing simulation method of the orthodontic effect of the orthodontic appliance, which only considers the orthodontic force applied to the dental arch after the orthodontic appliance is worn, and takes into account the influence of the wearing process of the orthodontic appliance on the orthodontic effect, so that the simulation process is closer to the actual wearing and orthodontic process, thereby greatly increasing the credibility of the simulation result

[0086] The specific embodiments of steps S1 to S3 are described in detail below with reference to the accompanying drawings.

[0087] Step S1 is used to obtain an initial dental arch digital model and a target dental arch digital model for predicting the orthodontic effect, wherein the initial dental arch digital model is a digital model determined based on the dental arch to be treated, and the target dental arch digital model is a digital model of the dental arch corresponding to the expected effect after orthodontic treatment of the dental arch to be treated.

[0088] There are various modeling methods for the initial dental arch digital model in the prior art, for example, the three-dimensional shape of the original data of each tissue in the oral cavity can be obtained by optical scanning, X-ray / ultrasound imaging, CT scanning or nuclear magnetic resonance, and a three-dimensional digital model of the dental arch can be further established by a three-dimensional modeling method. A dental arch digital model that can be applied to orthodontic treatment, such as digital design of dental implants or orthodontic appliances, generally includes a three-dimensional digital model of a dental arch composed of multiple teeth, periodontal tissue and jaw bones. FIG.

[0089] After obtaining the initial dental arch digital model, a doctor can make a diagnosis and issue a prescription based on the shape, and an experienced modeling personnel can adjust the initial dental arch digital model to the state expected to be achieved when the orthodontic treatment is completed, i.e., the target dental arch digital model, according to the prescription issued by the doctor. The method of generating the target dental arch digital model from the initial dental arch digital model according to the prescription has been widely used in the design and manufacturing process of the shell-shaped orthodontic appliance for correcting misaligned teeth.

[0090] The components of the dental arch digital model are diverse: it can be an independent maxillary digital model and / or a mandibular digital model, or a maxillary dental arch digital model and a mandibular dental arch digital model placed according to the positional relationship in the real three-dimensional space, thereby forming an "integrated" dental arch digital model. In addition, the data format of the dental arch digital model can also be adjusted according to the specific application requirements. For example, in some diagnostic, teaching and other application occasions, only the appearance structure of the dental arch needs to be displayed, at which time a triangular facet or the like data format can be used to form the outline of the teeth, periodontal tissue and jaw, etc. For example, when finite element simulation of orthodontic treatment is required, the various parts of the dental arch need to be solidified and given different material parameters to form the finite element model of the teeth, gums, periodontal membrane and jaw. The above-mentioned existing dental arch modeling method is known to those skilled in the art.

[0091] The dental arch digital model in the above-mentioned prior art, for example, the "integrated" dental arch model established according to the occlusal relationship, the positional relationship between the maxilla and the mandible of the model is often fixed and unchangeable. Through such a dental arch model, only the relative positional relationship between the maxilla and the mandible at the time of scanning and shooting the dental arch can be reflected, and the various occlusal processes of the mandible relative to the maxilla cannot be dynamically reproduced.

[0092] However, for some patients undergoing orthodontic treatment, there can be various oral problems. For example, a child patient in the mixed dentition period can have two or more of the following problems: malposition of deciduous teeth, malposition of permanent teeth, crowded dentition, and malocclusion of the upper and lower jaws. Orthodontic treatment of such a patient can require a combination of various corrective measures such as tooth alignment, arch expansion and occlusal relationship adjustment. Therefore, in order to perform orthodontic treatment on a patient with the above-mentioned conditions, it is necessary to more comprehensively and accurately reproduce the state of the patient's dental arch before treatment and the state expected to be achieved after treatment.

[0093] Therefore, in the embodiments of the present application, the dental arch digital model established in step S1 is a dynamic dental arch digital model that can accurately reproduce the actual occlusal process of the upper and lower jaws. Specifically, in some preferred embodiments of the present application, the initial dental arch digital model is generated based on the actual morphology of the upper and lower jaws and the actual occlusal relationship of the upper and lower jaws before the start of the orthodontic period. Further, the initial dental arch digital model can be moved relative to the upper and lower jaws according to the actual occlusal relationship of the upper and lower jaws before the start of the orthodontic period.

[0094] The actual occlusal relationship reflects the actual positional relationship of the teeth of the upper and lower jaws before the start of the orthodontic treatment, and is an important indicator for judging malocclusion. Figure 6 A schematic diagram of the upper jaw and the lower jaw connected by the temporomandibular joint is shown, Figures 7A to 7D Various forms of movement of the lower jaw are shown. For example, Figure 6As shown in Figure 7, the maxillary portion 310 (including the maxillary bone, maxillary dentition, and soft tissues such as the periodontal ligament and gingiva (not shown in the figure)) and the mandibular portion 320 (including the mandibular bone, mandibular dentition, and soft tissues such as the periodontal ligament and gingiva (not shown in the figure)) are connected by the temporomandibular joint. The temporomandibular joint includes an articular disc, a joint capsule, and a condyle 330 located within it, capable of rotation and translation. When the mandibular portion 320 is subjected to forces from different muscle groups such as the masseter, temporalis, medial pterygoid, and lateral pterygoid muscles, it undergoes various movements relative to the maxillary portion 310 (e.g., ...). Figures 7A to 7D The mandible is shown to be moving relative to the maxilla (opening, closing, protruding, retracting, and laterally shifting). Simultaneously, the condyle 330 is also pulled and rotates and translates accordingly, thus forming a specific movement trajectory or curve. The occlusal relationship between the maxilla and mandible can be accurately described through the aforementioned movement trajectory or curve of the condyle 330.

[0095] In some preferred embodiments of this application, the actual occlusal relationship includes the movement parameters of the condyle during actual occlusion. Further, the movement parameters of the condyle during actual occlusion include the inclination angle and / or curve of the movement trajectory of the condyle during actual occlusion. In some preferred embodiments of this application, the actual occlusal relationship can be automatically obtained by measuring the teeth to be treated using an articulator. An articulator, also known as an occlusal appliance, is an instrument that mimics the upper and lower jaws and the temporomandibular joint, and can simulate the movement of the upper and lower jaws to a certain extent.

[0096] Figure 8 This diagram illustrates a jaw frame and a schematic diagram of how the relative positional relationship between the upper and lower jaws and the corresponding temporomandibular joint state are obtained through the jaw frame. Using the jaw frame 500 shown in the diagram, the relative positions of the upper and lower jaws at different stages of the actual occlusal process can be measured. Simultaneously, by locating the condyle at measurement point 530, the corresponding temporomandibular joint motion data can be obtained. Fitting the measurement data from multiple locations yields data such as the condyle's motion parameters during the actual occlusal process.

[0097] Figure 9 It shows the way Figure 8 The illustrated jawbone system represents a specific implementation procedure for obtaining the actual occlusal relationship, such as... Figure 9As shown, firstly, the relative position information of the upper and lower jaws and the state information of the temporomandibular joint of the measurement object in the occlusion state (i.e. the closed mouth state) are measured by the jaw frame, and the initial values of the position and inclination angle of the condyle are determined based on the above information; then, the relative position information of the upper and lower jaws and the state information of the temporomandibular joint in multiple different opening states during the gradual opening of the measurement object are measured, and the measurement values of the corresponding condyle position and inclination angle are determined; finally, the motion parameters such as the motion trajectory curve of the condyle and the inclination angle change trend are fitted according to the initial values of the condyle position and inclination angle and the measurement values in multiple different opening states, and the above motion parameters represent the actual occlusion relationship of the measurement object in the opening and closing process.

[0098] It can be easily imagined that for other types of occlusion processes, such as the protrusion and retraction movements of the lower jaw, and the lateral occlusion movements of the lower jaw, similar processes can be used to obtain the motion parameters of the condyle in the occlusion process.

[0099] After obtaining the above actual occlusion relationship, it can be used to bind the upper jaw model and the lower jaw model of the initial dental arch digital model, for example, in some specific embodiments of the present application, the motion trajectory of the lower jaw relative to the upper jaw in various types of occlusion processes is obtained based on the above actual occlusion relationship, and then the above motion trajectory is bound to the lower jaw model, thereby obtaining the initial dental arch digital model generated based on the actual occlusion relationship.

[0100] Figures 10A to 10C Fig. 4 shows a schematic diagram of an initial dental arch digital model dynamically reproducing the opening and closing process according to one specific embodiment of the present application, wherein the initial dental arch digital model 400 includes an upper jaw model 410 and a lower jaw model 420; further, the upper jaw model 410 is further subdivided into a plurality of upper jaw tooth models 411 and an upper jaw gingival model 412 according to different parts, and the lower jaw model 420 is further subdivided into a plurality of lower jaw tooth models 421 and a lower jaw gingival model 422 according to different parts; in addition, the upper jaw model 410 also includes models of the upper jaw bone, the upper jaw periodontal membrane and other parts located in the upper jaw gingival model 412 (not shown in the figure), and the lower jaw model 420 also includes models of the lower jaw bone, the lower jaw periodontal membrane and other parts located in the lower jaw gingival model 422 (not shown in the figure). In addition, in some embodiments, in order to facilitate the implementation of subsequent assembly, manufacturing and other steps, the initial dental arch digital model 400 also includes an upper abutment model 413 and a lower abutment model 423 adapted to a tooling fixture.

[0101] In some embodiments, the digital models of the above different parts can be respectively given corresponding materials to form finite element models that can be used for simulation. Obviously, when the orthodontic force received by the dental arch is simulated by finite elements, the above upper abutment model and lower abutment model do not need to be converted into finite element models and do not need to participate in the finite element simulation.

[0102] In some preferred embodiments, in order to more clearly show various types of occlusion processes, as shown in the initial dental arch digital model, the condyle is visually displayed at the equivalent position point AX (point 430 in the figure), and the actual occlusion relationship is visually displayed as the movement trajectory inclination angle of the condyle in the actual occlusion process or the movement trajectory curve (the movement trajectory of the condyle in the actual occlusion process is shown by the dashed line in the figure, and the angle between the dashed line and the horizontal line OP represents the movement trajectory inclination angle of the condyle in the actual occlusion process). Figures 10A to 10C

[0103] After obtaining the initial dental arch digital model, the doctor can qualitatively or quantitatively analyze the arrangement of the upper and lower dental arches, the curve of the upper and lower dental arches, and the occlusion relationship exhibited by the upper and lower jaws in various occlusion processes through the initial dental arch digital model, and then issue an orthodontic prescription according to the above analysis results. The items listed in the orthodontic prescription can include: at least one existing oral malformation problem and its severity; the setting of the orthodontic force applied to each part of the dental arch, such as the correction force applied to each tooth, the correction force applied to the upper and lower jaws, the traction force applied to adjust the occlusion relationship, etc.; the orthodontic effect expected to be achieved by oral orthodontics, such as the target position and attitude of each tooth at the end of the orthodontic period, the dental arch curve after expansion of the jaw bones, the adjusted occlusion relationship of the upper and lower jaws, etc.

[0104] After the above orthodontic prescription is determined, in order to design and manufacture the appliance, experienced modeling personnel can manually or automatically / semi-automatically adjust the initial dental arch digital model (the adjustment basis can be the target position of the teeth, the target width of the dental arch, the target state of the occlusion relationship, or the target movement trajectory of the upper and lower jaws, etc. recorded in the orthodontic prescription), thereby obtaining a target dental arch digital model, i.e., in the preferred embodiments of the present application, the target dental arch digital model is generated based on the target state of the upper and lower jaws at the end of the orthodontic period and the target occlusion relationship of the upper and lower jaws determined by the orthodontic prescription.

[0105] The specific acquisition methods of the initial dental arch digital model and the target dental arch digital model are described in detail above, and the modeling process can be performed simultaneously when various examinations and measurements are performed on the oral cavity, and after the modeling is completed, the initial dental arch digital model and the target dental arch digital model are saved into the case database, which can be called when the oral orthodontic effect is predicted in the subsequent process.

[0106] ​Step S2 is used to obtain the digital model of the appliance required for orthodontic effect prediction. The modeling of the digital model of the appliance is generally performed after the modeling of the target dental arch digital model, which is similar to the modeling of the digital model of the appliance completed and saved in the case database for subsequent orthodontic prediction. The method of generating the digital model of the appliance based on the target dental arch digital model is known to those skilled in the art, and will not be described here.

[0107] After the initial dental arch digital model, the target dental arch digital model and the digital model of the appliance are obtained through steps S1 and S2 respectively, the orthodontic effect of the dental arch wearing the appliance using the preset orthodontic parameter combination can be predicted through step S3.

[0108] Based on the analysis of the differences between the shell-shaped appliance and the occlusal induction appliance in shape, structure, material and treatment mechanism, it can be seen that, unlike the wearing and using process of the shell-shaped appliance, the occlusal induction appliance needs to accommodate the upper and lower jaws at the same time, and the material used is soft material such as medical silica gel. Therefore, the process of "wearing - occlusal training - removal" needs to be repeated every day during the orthodontic process. The different wearing methods and occlusal forces used in the above processes, as well as the different lengths of occlusal training performed every day, will all have corresponding effects on the final orthodontic effect. Therefore, when using the occlusal induction appliance for orthodontic treatment, the orthodontic scheme (i.e. the rules or criteria that need to be followed when using the appliance for orthodontic treatment) can include multiple predetermined orthodontic parameters.

[0109] Specifically, in some preferred embodiments of the present application, the orthodontic parameter combination can include the occlusal force of wearing the appliance, the length of time of wearing the appliance each time, the number of times of wearing the appliance per day, and the total number of days of the orthodontic period. In other preferred embodiments of the present application, those skilled in the art can also add other orthodontic parameters according to the specific circumstances of the initial dental arch and the appliance.

[0110] Specifically, as shown in Figure 11 In some preferred embodiments of the present application, step S3 further includes the following steps:

[0111] S31: taking the initial dental arch digital model as the current dental arch digital model;

[0112] S32: simulating the wearing process of the appliance based on the current dental arch digital model, the digital model of the appliance and the orthodontic parameters to determine the orthodontic force distribution of the current dental arch digital model after wearing the appliance;

[0113] S33: simulating the orthodontic process of the current wearing of the appliance based on the orthodontic force distribution and the orthodontic parameter combination to obtain the intermediate dental arch digital model after the end of the current orthodontic process.

[0114] S34: determining whether the orthodontic period is ended, if the result of the determination is yes, taking the intermediate dental arch digital model as the predicted dental arch digital model and ending the simulation, if the result of the determination is no, taking the intermediate dental arch digital model as the new current dental arch digital model and returning to step S32.

[0115] By Figure 11 It can be seen that in the embodiments of the present application, the simulation process of step S3 includes simulating at least one wearing process of the appliance (step S32) and at least one orthodontic process during the period from wearing to taking off (step S33). Specifically, the simulation of step S32 and step S33 can be performed using the finite element calculation method.

[0116] Figure 12 Specific steps of simulating the wearing process of the appliance in some embodiments of the present application are shown as follows: Figure 12 As shown, simulating the wearing process of the appliance can include the following steps:

[0117] First step: setting the current dental arch digital model and the finite element constitutive parameters of the appliance;

[0118] Second step: setting the finite element calculation parameters;

[0119] Third step: setting the initial value of the mandibular motion trajectory;

[0120] Fourth step: obtaining the orthodontic parameter combination and extracting the occlusal force information of wearing the appliance;

[0121] Fifth step: performing finite element calculation on the wearing process of the appliance based on the occlusal force of wearing the appliance and the initial value of the mandibular motion trajectory to obtain the simulation result. Specifically, the simulation result includes the motion trajectory of the mandible during the wearing process of the appliance and the orthodontic force distribution of the current dental arch digital model during the wearing process of the appliance and after wearing the appliance.

[0122] In some specific embodiments, the constitutive parameters include the density, elastic modulus, Poisson's ratio and other parameters of the appliance digital model and the dental arch digital model (including teeth, gums, periodontal membrane, dental arch bone) as well as the finite element unit parameters, model type and the like; the calculation parameters include the contact conditions and boundary conditions of the appliance digital model and the dental arch digital model and the like. The technique of setting constitutive parameters and calculation parameters for the digital model of finite element simulation is known to those skilled in the art, which will not be described here.

[0123] Among the existing various methods for simulating the treatment effect of shell-shaped appliances, the wearing / fitting process is often only treated simply and idealistically, and different wearing results caused by different wearing angles, speeds, applied bite forces, etc. during the wearing / fitting process are not simulated. For shell-shaped appliances that only move the upper or lower jaw, the above-mentioned simplified treatment is reasonable and does not affect the subsequent simulation accuracy. However, for orthodontic appliances such as bite-induced appliances that are soft and act on the upper and lower jaws at the same time, if the wearing process is not analyzed in more detail, the simulation error of the treatment effect after wearing will be greatly increased.

[0124] Unlike this, in the technical solution of the present application, the simulation of the wearing process includes the steps of setting the initial value of the mandibular movement trajectory and the bite force of the worn appliance. The initial value of the mandibular movement trajectory can also be equivalently replaced by the initial value of the movement parameter of the condyle during biting. The bite force of the worn appliance can be obtained by a force sensor arranged on the initial dental digital model. The force sensor is generally placed on the occlusal surface of multiple teeth, and when a forced force is applied to the upper and lower parts of the dynamic dental digital model to make them enter the appliance, the force sensor can measure the bite force received by the contact part of the appliance and the occlusal surface of the teeth. By setting the above-mentioned parameters, the real process of wearing the induced appliance with different bite types can be simulated more realistically, and the relative position of the dental arch and the appliance at the end of wearing and the distribution of orthodontic forces received by each part of the dental arch are more accurate.

[0125] In some specific embodiments, the end condition of the simulation of the wearing process can also be set in advance, for example, in some preferred embodiments of the present application, when the bite force of the upper and lower jaws during the wearing process is greater than the average value of the maximum bite force limit in the human conscious state, the simulation is ended.

[0126] In particular, in some preferred embodiments of the present application, the simulation of the appliance wearing process is performed by a nonlinear finite element calculation method, because most of the existing various finite element simulation methods for the treatment effect of orthodontic appliances only perform static analysis of the interaction between the teeth and the orthodontic appliance. Such static analysis linear finite element calculation can obtain relatively accurate results. However, the wearing process of bite-induced appliances is a complex and dynamic interaction process between the structures of the upper and lower jaws and the soft medical silicone object, and only using static and linear calculation cannot obtain accurate calculation results.

[0127] In some preferred embodiments of the present application, simulating the wearing process further comprises setting one or more of the following forced loading conditions: forced velocity condition, forced displacement condition, forced rotation condition. By setting the forced loading velocity condition, the calculation efficiency of simulating the wearing process of the appliance can be improved.

[0128] Setting the forced loading velocity condition and other forced loading conditions may cause structural oscillation of the digital model of the appliance, resulting in unreasonable changes in the shape of the appliance. Therefore, in some preferred embodiments of the present application, simulating the wearing process further comprises setting a damping parameter, which can be a mass damping or other equivalent parameter, and the action time range of the damping parameter is between 1-1000 times the time step of the finite element model. Figure 13 A specific embodiment is shown before and after the addition of mass damping, and the structural oscillation of the digital model of the appliance is compared. As can be seen from the figure, the addition of mass damping can significantly reduce the error of the calculation results caused by structural oscillation.

[0129] The above describes in detail the specific implementation steps of step S32 for simulating the wearing process of the appliance. By simulating the wearing process of the appliance, the distribution of orthodontic forces exerted by the appliance on each part of the dental arch at the time of wearing can be obtained. Specifically, the orthodontic forces include at least one of the following orthodontic forces: orthodontic force on at least one tooth, orthodontic force on the maxillary bone and / or the mandibular bone, and traction force on the condyle.

[0130] Figures 14A to 14C A specific wearing process is simulated, as shown in the figure, as the maxillary model 410 and the mandibular model 420 of the current dental arch digital model gradually enter the appliance model 600, the shape of the appliance model 600 changes, and the orthodontic forces are exerted on each part of the current dental arch digital model accordingly.

[0131] Figures 15A to 15C The changes in the orthodontic forces on each part of the maxillary model 410 at each stage of the wearing process are shown, and the sizes and directions of the orthodontic forces acting on different parts are shown by arrows of different lengths. Similarly, by simulating the wearing process, the changes in the orthodontic forces on the mandibular model and the condyle at each stage of the wearing process can also be obtained.

[0132] After obtaining the distribution of the orthodontic forces after wearing the appliance, it is used as the stress applied to the current dental arch digital model, and the strain of each part of the dental arch at the end of the orthodontic process can be simulated by the finite element calculation method, i.e., the intermediate dental arch digital model at the end of the orthodontic process is obtained.

[0133] In the embodiments of the present application, the orthodontic treatment process refers to the continuous orthodontic treatment process of the dental arch during the wearing of the appliance and the removal of the appliance. Obviously, the end condition of the simulation of the orthodontic treatment process is the length of time of wearing the appliance. In the above treatment process, the occlusal force of the wearing of the appliance and the length of time of each wearing of the appliance will affect the effect of the orthodontic treatment process and cause the shape and occlusal relationship of the generated intermediate dental arch digital model to be different. The method of applying stress to the finite element model to simulate the strain of the finite element model is known to those skilled in the art, and the assignment of the constitutive parameters and the calculation parameters of the digital model participating in the simulation is the same as step S32, which will not be described here.

[0134] Steps S32 and S33 simulate the wearing process and the orthodontic treatment process respectively, and obtain the intermediate dental arch digital model after the simulation ends. For a specific orthodontic scheme, the orthodontic parameter combination further includes the number of wearing the appliance per day and the total number of days of the orthodontic period. In the process of cyclically executing steps S32 and S33, one day can include multiple “wearing-occlusal training-removal” processes, and the above process can be repeated every day in the orthodontic period. Finally, the simulation process ends after the number of days of the orthodontic period is reached, and the intermediate dental arch digital model obtained at this time is taken as the predicted dental arch digital model.

[0135] Similar to the initial dental arch digital model and the target dental arch digital model, the predicted dental arch digital model represents the predicted shape of the upper and lower jaws and the predicted occlusal relationship of the upper and lower jaws at the end of the orthodontic period obtained by simulation, and the relative movement of the upper and lower jaws can be performed according to the predicted occlusal relationship. Obviously, after obtaining the above predicted dental arch digital model, quantitative or qualitative analysis can be performed according to the difference between the predicted dental arch digital model and the target dental arch digital model to adjust the orthodontic scheme or optimize the design of the appliance.

[0136] The above is a description of the specific implementation of the orthodontic effect prediction method provided by the present application. Through the above method, the prediction result of the corresponding orthodontic effect can be obtained according to the orthodontic parameter combination in a predetermined orthodontic scheme. However, since the orthodontic parameter combination included in the orthodontic scheme contains multiple parameters that affect the orthodontic effect, the mutual restriction and coupling effect between the parameters make it difficult to find the best orthodontic scheme by simply adjusting a parameter.

[0137] To solve the above problem, another aspect of the embodiments of the present application provides a method for determining the optimal orthodontic scheme, which uses the above orthodontic effect prediction method to obtain and evaluate the corresponding orthodontic effects of multiple groups of orthodontic parameter combinations to determine the optimal orthodontic scheme. As shown in Figure 16 The optimal orthodontic scheme determination method provided by the embodiments of the present application includes the following steps:

[0138] A1: performing the steps S1, S2 to obtain the initial dental arch digital model, the target dental arch digital model and the digital model of the appliance;

[0139] A2: establishing a search grid of orthodontic parameters and obtaining each set of orthodontic parameter combinations corresponding to each search grid point;

[0140] A3: traversing the search grid, using each set of orthodontic parameter combinations to simulate the wearing of the appliance and the orthodontic process through the step S3 to obtain each predicted dental arch digital model corresponding to each set of orthodontic parameter combinations;

[0141] A4: evaluating the orthodontic effects of each set of orthodontic parameter combinations based on the target dental arch digital model and each predicted dental arch digital model, and determining the optimal orthodontic scheme or optimizing the digital model of the appliance according to the evaluation results.

[0142] The initial dental arch digital model, the target dental arch digital model and the digital model of the appliance obtained in step A1 can be generated by the modeling method described above, in addition, the digital models that have been modeled and saved can also be retrieved and called in the case database.

[0143] Step A2 is used to establish a search grid of orthodontic parameter combinations. In some embodiments of the present application, the orthodontic parameter combination includes at least two orthodontic parameters; in some preferred embodiments of the present application, the orthodontic parameter combination includes three or more orthodontic parameters. As described above, the optional orthodontic parameters include: the occlusal force of wearing the appliance, the duration of wearing the appliance each time, the number of wearing the appliance each day, the total number of days of the orthodontic period, etc. In addition to the above orthodontic parameters, those skilled in the art can consider the factors affecting the orthodontic effect of the appliance on the whole dental arch or a specific part, and add corresponding orthodontic parameters to the orthodontic parameter combination.

[0144] For each orthodontic parameter, the selection of the value range and the search step can be determined by considering the conventional situation of orthodontic treatment. For example, for the occlusal force of wearing the appliance, the minimum and maximum values of the value range can be taken as the lower limit and the upper limit of the muscle training occlusal force, and the search step is set to 1 kg. In addition, considering the case of wearing the appliance during sleep, the maximum value of the value range can be appropriately expanded; for example, for the duration of wearing the appliance each time in the orthodontic period, the minimum and maximum values of the value range can be set to 1 hour and 4 hours respectively, and the search step is 0.5 hours. In addition, the wearing of the orthodontic appliance can be further subdivided, such as adding the parameter of wearing time during sleep and setting the corresponding value range and step.

[0145] After the search grid is generated, each grid point corresponds to a specific set of orthodontic parameters. In step A3, the search grid is traversed, and each set of orthodontic parameters is used to simulate the wearing of the appliance and the orthodontic process. This results in a predicted dental arch digital model corresponding to each set of orthodontic parameters. The simulation process has been described in detail in the specific embodiments of the method for predicting the effect of orthodontic treatment.

[0146] The predicted dental arch digital models obtained by simulating different combinations of orthodontic parameters differ in shape from the target dental arch digital model. These shape differences can be used to qualitatively evaluate the orthodontic effects of different combinations of orthodontic parameters and select the optimal orthodontic parameters to develop an orthodontic treatment plan. However, the search grid may contain a large number of grid points, making it time-consuming to analyze and evaluate each one manually. Therefore, a feasible analysis method is to quantitatively and automatically analyze the deviation functions generated by comparing the predicted dental arch digital models with the target dental arch digital model.

[0147] Step A4 is used to evaluate the simulation results corresponding to each set of orthodontic parameters and determine the optimal orthodontic treatment plan. In some embodiments of the present application, step A4 further includes the following steps:

[0148] A41: Determine the deviation function corresponding to each set of orthodontic parameters based on the deviation between each predicted dental arch digital model and the target dental arch digital model.

[0149] A42: Determine the number N of deviation functions that are less than the deviation threshold.

[0150] A43: If N = 0, optimize the appliance digital model. If N = 1, select the set of orthodontic parameters corresponding to the deviation function to develop the optimal orthodontic treatment plan. If N ≥ 2, develop multiple orthodontic treatment plans based on multiple sets of orthodontic parameters corresponding to multiple deviation functions, and select the optimal orthodontic treatment plan.

[0151] The deviation function is used to quantitatively analyze the deviation between the simulation results of each set of orthodontic parameters and the expected orthodontic target. In some embodiments of the present application, the deviation function is generated based on at least one of the following values: the pose difference of at least one tooth to be treated in the predicted dental arch digital model and the target dental arch digital model, the difference between the dental arch shape parameters of the predicted dental arch digital model and the target dental arch digital model, and the difference between the occlusal relationship of the predicted dental arch digital model and the target dental arch digital model. One optional deviation function is generated by weighted summing the above differences. In addition, other forms of deviation functions can also be selected without departing from the concept of the present application.

[0152] The specific form of the deviation function is related to the selection of the combination of orthodontic parameters used for searching. For example, in some embodiments, the combination of orthodontic parameters used for searching only includes the bite force of wearing the appliance, i.e., the search grid is a 1-dimensional grid, and accordingly, the length of each wearing of the appliance, the number of wearing the appliance per day, the total number of days of the orthodontic period, and the like parameters adopt preset values, and the deviation function obtained at this time is a 1-dimensional function including only the bite force as a variable. In other embodiments, the combination of orthodontic parameters used for searching includes the bite force of wearing the appliance and the length of each wearing of the appliance in the orthodontic period, i.e., the search grid is a 2-dimensional grid, and accordingly, the number of wearing per day and the total number of days of the orthodontic period, and the like parameters adopt preset values, and the deviation function obtained at this time is a 2-dimensional function including the bite force and the length of each wearing as variables.

[0153] When the deviation function corresponding to the 1st combination of orthodontic parameters is less than the preset deviation threshold, it can be considered that the combination of orthodontic parameters can more ideally achieve the orthodontic target, and the combination of orthodontic parameters can be selected to formulate the optimal orthodontic scheme. If there are more than one combination of orthodontic parameters corresponding to the deviation function less than the deviation threshold, multiple orthodontic schemes will be generated through the multiple combinations of orthodontic parameters corresponding thereto, and at this time, the optimal orthodontic scheme can be selected from the multiple orthodontic schemes by the attending doctor in combination with the actual situation of orthodontics. If there is no deviation function less than the deviation threshold, it means that the currently designed appliance can not achieve the expected orthodontic effect, and at this time, the appliance digital model can be optimized, and the search is performed again for the optimized appliance digital model.

[0154] The specific embodiments of the present application are described in detail above, and for those skilled in the art, without departing from the principles of the present application, some improvements and modifications can be made to the present application, and these improvements and modifications also belong to the protection scope of the claims of the present application.

Claims

1. A method for predicting the effect of orthodontic treatment, used to predict the orthodontic effect of wearing orthodontic appliances, characterized in that, Includes the following steps: S1: Obtain the initial and target digital models of the dental arch; S2: Obtain the digital model of the orthodontic appliance; S3: Based on the initial digital model of the dentition, the digital model of the appliance, and the combination of orthodontic parameters, the wearing of the appliance and the orthodontic process are simulated to obtain a predicted digital model of the dentition. The orthodontic appliance is an occlusion guiding orthodontic appliance, which includes a U-shaped outer wall and an inner wall, and an occlusion pad connecting the inner wall and the outer wall. The initial digital model of the jaw, the predicted digital model of the jaw, and the target digital model of the jaw can all perform relative movements of the upper and lower jaws according to the corresponding occlusal relationship, which includes the motion parameters of the condyle during the occlusal process.

2. The method for predicting the effect of orthodontic treatment according to claim 1, characterized in that: The initial digital model of the jaws is generated based on the actual morphology of the upper and lower jaws and the actual occlusal relationship of the upper and lower jaws before the start of the orthodontic cycle. The target dental digital model is generated based on the target morphology of the maxilla and mandible and the target occlusal relationship of the maxilla and mandible as determined by the orthodontic prescription at the end of the orthodontic cycle. The predicted dental digital model is generated based on the predicted morphology of the upper and lower jaws and the predicted occlusal relationship at the end of the orthodontic cycle, obtained by simulating the wearing of the orthodontic appliance and the orthodontic process.

3. The method for predicting the effect of orthodontic treatment according to claim 1, characterized in that: The motion parameters of the condyle during occlusion include the inclination angle and / or the trajectory curve of the condyle during occlusion.

4. The method for predicting the effect of orthodontic treatment according to claim 2, characterized in that: The actual occlusal relationship is automatically obtained by measuring the teeth to be treated using an articulator.

5. The method for predicting the effect of orthodontic treatment according to claim 1, characterized in that, The orthodontic parameter combination includes one or more of the following parameters: Bite force while wearing braces, duration of each brace wearing session, number of times braces are worn per day, and total number of days in the orthodontic cycle.

6. The method for predicting the effect of orthodontic treatment according to claim 5, characterized in that: The biting force of the orthodontic appliance is obtained by a force sensor set on the initial digital model of the jaw.

7. The method for predicting the effect of orthodontic treatment according to claim 5, characterized in that: The simulation of the wearing and orthodontic process of the orthodontic appliance described in step S3 includes simulating at least one wearing process of the orthodontic appliance and at least one orthodontic process from wearing to removal.

8. The method for predicting the effect of orthodontic treatment according to claim 7, characterized in that, Step S3 further includes the following steps: S31: Use the initial digital model of the dental jaw as the current digital model of the dental jaw; S32: Based on the current digital model of the jaw, the digital model of the appliance, and the combination of orthodontic parameters, simulate the wearing process of the appliance to determine the distribution of orthodontic forces on the current digital model of the jaw after wearing the appliance. S33: Based on the orthodontic force distribution and orthodontic parameters, the orthodontic process of wearing the appliance is simulated to obtain a digital model of the intermediate teeth after the orthodontic process is completed. S34: Determine whether the orthodontic cycle has ended. If the result is yes, use the intermediate dentition digital model as the predicted dentition digital model and end the simulation. If the result is no, use the intermediate dentition digital model as the new current dentition digital model and return to step S32.

9. The method for predicting the effect of orthodontic treatment according to claim 8, characterized in that, The orthodontic force includes at least one of the following corrective forces: Orthodontic force on at least one tooth, orthodontic force on the maxilla and / or mandible, and traction force on the condyle.

10. The method for predicting the effect of orthodontic treatment according to claim 8, characterized in that: The simulation was performed using the nonlinear finite element method.

11. The method for predicting the effect of orthodontic treatment according to claim 10, characterized in that, Simulating the wearing process involves setting one or more of the following forced loading conditions: Forced velocity condition, forced displacement condition, forced rotation condition.

12. The method for predicting the effect of orthodontic treatment according to claim 11, characterized in that: The forced speed condition is 0.001 m / s to 3 m / s; Simulating the wearing process also includes setting damping parameters.

13. A method for determining an optimal orthodontic scheme, comprising using the orthodontic effect prediction method as described in any one of claims 1 to 12 to obtain and evaluate the orthodontic effects corresponding to multiple combinations of orthodontic parameters to determine the optimal orthodontic scheme, characterized in that, Includes the following steps: A1: Perform steps S1 and S2 to obtain the initial digital model of the jaw, the target digital model of the jaw, and the digital model of the orthodontic appliance; A2: Establish a search grid for orthodontic parameters and obtain the combinations of orthodontic parameters corresponding to each search grid point; A3: Traverse the search grid, use each set of orthodontic parameter combinations, simulate the wearing of the orthodontic appliance and the orthodontic process through step S3, and predict each predicted digital model of the dentition corresponding to each set of orthodontic parameter combinations. A4: Evaluate the orthodontic effects of each combination of orthodontic parameters based on the target dentition digital model and each predicted dentition digital model, and determine the optimal orthodontic plan or optimize the digital model of the aligner based on the evaluation results.

14. The method for determining the optimal orthodontic scheme according to claim 13, characterized in that: Step A4 further includes the following steps: A41: Determine the deviation functions corresponding to each group of orthodontic parameter combinations based on the deviation between each predicted digital model of the dentition and the target digital model of the dentition; A42: Determine the number N of deviation functions that are less than the deviation threshold; A43: If N=0, optimize the digital model of the orthodontic appliance; if N=1, select a set of orthodontic parameters corresponding to the deviation function to formulate the optimal orthodontic plan; if N≥2, formulate multiple orthodontic plans based on multiple sets of orthodontic parameter combinations corresponding to multiple deviation functions, and select the optimal orthodontic plan from them.

15. The method for determining the optimal orthodontic scheme according to claim 14, characterized in that, The deviation function is generated based on at least one of the following values: The difference in pose of at least one tooth to be treated on the predicted digital model of the dentition and the target digital model of the dentition, the difference in dental arch morphology parameters between the predicted digital model of the dentition and the target digital model of the dentition, and the difference in occlusal relationship between the predicted digital model of the dentition and the target digital model of the dentition.

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