Method of determining orthodontic treatment regimen

Abstract

A method of generating an orthodontic treatment regimen for a dental arch of a user, comprising the following consecutive steps: (a) generating an initial model and a final model of the dental arch exhibiting an initial moment and a final moment; (b) determining, by the computer, a deformation scenario that transforms the initial model into a final model by displacement of the tooth model; (c) determining, by the computer,-a duration of time for implementing the deformation scenario; and-an intermediate time between an initial time and a final time of the deformation of the dental arch according to the deformation scenario.

Description

Technical Field

[0001] The present invention relates to a method for determining an orthodontic treatment plan, comprising determining a complete orthodontic treatment plan or a part of a complete orthodontic treatment plan.

[0002] The invention also relates to a computer program as well as a computer and a system for implementing such a method. Background Art

[0003] Orthodontic treatment aims to change the alignment of a user's teeth using orthodontic appliances.

[0004] Orthodontic devices include archwire and bracket orthodontic devices and orthodontic appliances.

[0005] Archwire and bracket orthodontic appliances have brackets, or "brackets," fixed to the teeth and connected to each other by an archwire, usually made of shape memory material. It reacts quickly to the movement of the teeth of the user being treated.

[0006] An aligner is a removable, one-piece appliance, usually made of a transparent polymer material. It has recesses shaped to accommodate a number of teeth on the dental arch, usually all of the teeth on the dental arch. The shape of the recesses is adjusted to keep the aligner fixed on the teeth while correcting the position of certain teeth. The initial effect of an orthodontic aligner is slower than that of an archwire and bracket orthodontic appliance. However, the aligner can be replaced by the user at his or her own convenience. In addition, the aligner is more discreet than an archwire and bracket appliance.

[0007] The implementation of orthodontic treatment requires the preparation of an orthodontic treatment plan in advance in order to plan the subsequent orthodontic treatment steps. Therefore, the orthodontic treatment plan defines the time when the dentist plans to check the dental arch and / or modify the orthodontic appliances, such as the time when the orthodontic appliances (such as orthodontic braces) are replaced, and / or the time when the orthodontic arch wire is replaced, and / or the time when the orthodontic appliances are planned to be made.

[0008] Typically, the orthodontic treatment planning is done by the dentist using a computer. In particular, the computer allows him to visualize the model of the dental arch and to modify this model in order to determine the possible evolutions of the position and orientation of each tooth until all the teeth of the dental arch reach the desired arrangement, this evolution being compatible with the evolutions of the positions and orientations of the other teeth. Thus, the dentist succeeds in determining a series of three-dimensional digital models, comprising a model representing the dental arch at the beginning of the orthodontic treatment, a model representing the dental arch at the end of the orthodontic treatment, and one or more "intermediate" models representing the dental arch at intermediate moments between the beginning and the end of the orthodontic treatment, the intermediate moments being the moments when the dentist plans to check the dental arch and / or modify and / or make orthodontic appliances. This series of models or "deformation scenarios" and the intermediate moments define the orthodontic treatment plan.

[0009] Software for processing dental arch models and generating orthodontic treatment plans are well known. However, they require learning the software and orthodontic skills. Orthodontic treatment planning can be laborious and time-consuming.

[0010] Additionally, these software may cause orthodontic treatment plans to result in rapid tooth displacement, which may be harmful to the user's health.

[0011] There is a need for methods and systems that allow for improved implementation of orthodontic treatment plans.

[0012] The object of the present invention is to meet this need. Summary of the invention SUMMARY OF THE INVENTION

[0014] According to a first main aspect, the present invention provides a method of generating an orthodontic treatment plan for a dental arch of a user, the method comprising the following consecutive steps:

[0015] (a) generating or acquiring an "initial" model which represents the dental arch in three dimensions at an initial moment, said initial model being cut into a tooth model and, optionally, a gum model, and

[0016] generating or acquiring a "final" model showing said dental arch in a "final" arrangement of the desired dental model at the end of said orthodontic treatment;

[0017] (b) determining by computer a set of continuous basic deformations, wherein the basic deformations transform the initial model into the final model by displacement of the tooth model, wherein each of the basic deformations follows a respective set of constraints, and the model obtained by continuous basic deformations is called a "transition model", and the set of continuous transition models is connected into a "basic deformation scenario";

[0018] (c) determined by a computer,

[0019] - a duration, called "treatment duration", i.e. from said initial moment, during which the deformation of the dental arch is achieved according to said basic deformation scenario, until the final arrangement is obtained at said final moment; and

[0020] - intermediate moments between the initial moment and the final moment of the dental arch deformation according to the basic deformation scenario, said intermediate moments being the moments when the dentist plans to check the dental arch and / or modify and / or produce an orthodontic appliance,

[0021] The basic deformation scenario and the intermediate moments define the orthodontic treatment plan, referred to as the "basic orthodontic treatment plan".

[0022] According to the basic orthodontic treatment plan, the moment when the dental arch is expected to take on the shape shown in the transition model is called the "transition moment".

[0023] As will be described in detail below in the description, the computer thus creates a basic orthodontic treatment plan based only on the initial model and the final model, quickly and automatically, i.e. without human intervention. The automated creation of an orthodontic treatment plan can advantageously be optimized, in particular by meta-heuristic methods, which allows obtaining performance that is very difficult to achieve manually, in particular by avoiding collisions or ensuring that the teeth are displaced as regularly as possible or as quickly as possible.

[0024] Preferably, the method according to the first main aspect of the present invention also has one or more of the following optional features:

[0025] - In step (a), the computer determines the final model based on the initial model;

[0026] - In step (a), in order to determine the final model, the computer:

[0027] - Analyze the shape of the initial model to determine the curvature and length of the dental arch and define a baseline with said curvature and length, then,

[0028] - for each of a plurality of dental models, preferably for each dental model of the initial model, determining the position and orientation of said dental model relative to said baseline, preferably according to predefined rules and / or by assimilating the dental arch of the user to a historical dental arch similar to the dental arch of the user;

[0029] - Preferably, before step (a), the predefined rules are determined by statistical processing of historical data;

[0030] - in step (b), the set of constraints comprises user-defined constraints, preferably specifying the importance the user attaches to the speed of orthodontic treatment, and / or the pain caused by orthodontic treatment, and / or the comfort during orthodontic treatment, and / or the cost of orthodontic treatment, and / or the aesthetic impact of orthodontic treatment, and / or the reliability of orthodontic treatment, i.e. the likelihood that orthodontic treatment will produce the expected results, and / or the duration of wearing orthodontic appliances, and / or the functional goals of orthodontic or pre-set treatment;

[0031] - in step (b), the computer displays a dynamic form suitable for inputting (preferably by a user) at least part of the information required to define the set of constraints, in particular the information required to define the demanding constraints;

[0032] - in step (b), said set of constraints allows a limited penetration of the tooth model into an adjacent tooth model, said penetration limit preferably being determined by the possibility of filing at least one tooth modeled by said tooth model, said possibility preferably being assessed according to orthodontic rules, preferably being assessed by a dentist during treatment,

[0033] To avoid collision between the teeth caused by the penetration;

[0034] - In step (b), the computer implements an optimization algorithm, preferably a first optimization algorithm, to determine a basic deformation scenario so that the model is as close as possible to the final model, and / or implements a second optimization algorithm to determine a basic deformation scenario that best meets one or more requirements set by one or more users;

[0035] - In step (b), the computer

[0036] - searching for a "coarse" deformation scenario comprising a coarse initial model comprising less than 5000 points, preferably less than 2000 points, preferably less than 1000 points, preferably less than 500 points, preferably less than 100 points and / or more than 50 points, the coarse initial model being obtained by simplifying a fine initial model comprising more points than the coarse initial model, preferably comprising 1.1, or 1.5, or 2, or 5, or 10 or 100 times more points than the coarse initial model, and then

[0037] - at least partially complete the transition model and the final model, i.e. add points to these models,

[0038] - determine, in the rough deformation scenario where the transition model and the final model have been completed, whether the tooth models collide unacceptably, and

[0039] In case of unacceptable collisions, adding points to the rough initial model, preferably to the collision area, preferably at least to the transition model and the final model within the collision area, or to all points to the transition model and the final model, and

[0040] - using the rough initial model to which the points have been added, repeating the above search, preferably continuing the cycle until a deformation scenario without unacceptable collisions is obtained, which constitutes the base deformation scenario;

[0041] - At the beginning of step (c), the computer

[0042] - for each tooth model, determining the closest moment to the initial moment that the tooth model can reach, its appearance in the final model or "path end moment", according to the basic deformation scenarios determined in step (b);

[0043] - Determine, among all tooth models, the tooth model whose path end moment is farthest from the initial moment, i.e., the "boundary tooth model";

[0044] - Setting the final time as the path end time of the boundary tooth model;

[0045] The computer preferably determines the end-of-path moment of the tooth model, preferably of each tooth model, by representing the displacement of the tooth model in the base deformation scenario

[0046] The distance divided by the speed representing the movement ability of the tooth model;

[0047] - In step (c), the computer determines the intermediate time by determining the intermediate time according to one or more

[0048] The ability of the orthodontic appliance to move the teeth modeled by the tooth model, preferably according to the ability of the orthodontic appliance to move the teeth modeled by the tooth model, the duration of treatment, and / or the treatment time is divided into equal time intervals, each interval preferably corresponding to the expected duration of use of the orthodontic appliance by the user, or corresponding to the control of orthodontic

[0049] the frequency with which treatment is successfully performed, which frequency is preferably predetermined;

[0050] - The method comprises, after step (c), the following first step (d):

[0051] (d) determining by computer a new deformation scenario, referred to as the "first revised deformation scenario",

[0052] - wherein the outer shape of the boundary tooth model, at any intermediate moment, preferably at any transition moment, is defined by the base deformation scenario determined in step (b),

[0053] and

[0054] - wherein the displacement speed, preferably each displacement speed, of at least one tooth model, except said boundary tooth model, i.e. the "slow tooth model", is modified between an initial moment and a final moment, i.e. wherein at least one speed parameter is reduced or optimized, preferably minimized, the first modified deformation scenario and said intermediate moments defining a new orthodontic treatment plan, referred to as the "first modified orthodontic treatment plan";

[0055] - Speed ​​parameters are selected from:

[0056] - the maximum value of the displacement speed achieved by the slow tooth model between the initial moment and the final moment, and / or

[0057] - the difference between the maximum value of the displacement speed and the minimum value of the displacement speed of the slow tooth model between the initial moment and the final moment, and / or

[0058] - the average change in the displacement speed of the slow tooth model between the initial moment and the final moment;

[0059] - Determine a first modified deformation scenario so that the position between the initial moment and the final moment

[0060] The maximum value of the displacement velocity is less than the initial value in the base deformation scenario determined in step (b).

[0061] The maximum value of said displacement velocity between the moment and the final moment;

[0062] - the method comprises, after said first step (d) one or more consecutive additional steps (d), each additional step (d) comprising determining by a computer an additional modified deformation scenario, wherein

[0063] - the boundary tooth model follows the path defined by the base deformation scenario determined in step (b), and

[0064] - in a step (d) preceding said additional step (d), said slow tooth model follows a path defined by said modified deformation scenario determined in said previous step (d) or said previous step (d), respectively,

[0065] Since an additional revised deformation scenario is determined for reducing or optimizing, preferably minimizing, said at least one speed parameter of at least one "additional" slow tooth model (different from the slow tooth model in the previous step (d)) between the initial moment and the final moment, the orthodontic treatment plan so modified is referred to as an "additional revised orthodontic treatment plan";

[0066] - the slow tooth model of the first step (d) or of the additional step (d) is selected according to the criterion of usefulness for the dentist and / or the user, respectively, preferably according to the risk to the user's health resulting from the application of the basic deformation scenario or the orthodontic treatment correction of the previous step (d);

[0067] - Usefulness criteria define usefulness in limiting health risks to users and / or satisfying user requirements;

[0068] - the slow tooth model in the first step (d) or in the additional step (d) is selected according to the risk to the health of the user posed by the use of high displacement speeds, in particular the displacement speed used corresponds to the physiologically acceptable maximum displacement speed of the slow teeth being modeled;

[0069] - the closer the additional step (d) is to step (c), the higher the risk, i.e. the computer will preferentially correct the displacement speed of the tooth model with the highest risk caused by rapid displacement;

[0070] - Preferably, the method comprises step (d) for each tooth model, except for said boundary tooth model;

[0071] - After step (c), the method optionally comprises step (d) or a supplementary step

[0072] (d), the following steps (e):

[0073] (e) designing and manufacturing at least one orthodontic appliance according to the basic orthodontic treatment plan obtained in step (c) or the orthodontic treatment revision plan obtained in step (d) or a cycle of step (d);

[0074] - the orthodontic device is an orthodontic appliance, and the intermediate time refers specifically to the time when the orthodontic appliance is planned to be replaced;

[0075] - the orthodontic device is an orthodontic archwire and / or an auxiliary device, and the intermediate moment is the moment when the orthodontic archwire and / or the auxiliary device is planned to be replaced;

[0076] - the auxiliary device is selected from hooks, buttons, splints, elastic chains, springs, elastic bands and micro screws;

[0077] - the orthodontic appliance is a kit comprising an orthodontic archwire and brackets (English "brackets") for fixing the orthodontic archwire to the teeth, and the intermediate moment refers specifically to the moment when the archwire and / or one or more brackets are planned to be replaced;

[0078] -The computer submits the basic orthodontic treatment plan and / or the revised orthodontic treatment plan to the dentist for verification.

[0079] A complete orthodontic treatment usually comprises several stages. Each stage or "part of orthodontic treatment" may be the target of an orthodontic treatment plan according to the method of the invention, wherein the initial model represents the dental arch at the beginning of the relevant stage, and the final model represents the dental arch in the arrangement of the desired tooth model at the end of the stage.

[0080] Therefore, the present invention also relates to a method for generating a complete orthodontic treatment plan for a user's dental arch, wherein the complete orthodontic treatment consists of a series of partial orthodontic treatments, each of which corresponds to a stage of the complete orthodontic treatment, the method comprising the following consecutive steps:

[0081] (A') generating or acquiring a first "beginning of stage" model, which presents the dental arch at the beginning of the first stage of complete orthodontic treatment, the first model being cut into tooth models, and generating or acquiring a last "end of stage" model, which presents the dental arch arranged according to the desired tooth model at the end of the last stage of complete orthodontic treatment (i.e., the end of complete orthodontic treatment);

[0082] (B') for each stage from the first stage to the penultimate stage, determining, preferably by computer or computer-assisted dental practitioner determination, a corresponding end-stage model of the dental arch presenting the desired tooth model arrangement at the end of the stage;

[0083] (C') For each stage, a method comprising steps (a) to (c), preferably comprising step (d), preferably one cycle of step (d), is implemented, wherein the initial model is the model at the beginning of the stage and the final model is the model at the end of the stage.

[0084] The method implemented in step (C') may include one or more optional features described in this specification.

[0085] The above-mentioned tooth model velocity evolution correction method can be generalized.

[0086] According to a first main aspect, the present invention provides a method of generating an orthodontic treatment plan for all or part of a user's dental arch, the method comprising the following consecutive steps:

[0087] (A) preferably according to step (a),

[0088] - generating or acquiring an "initial" model which three-dimensionally represents the dental arch at an initial moment, said initial model being cut into tooth models, and

[0089] - generating or acquiring a "final" model which three-dimensionally represents said dental arch in the "final" arrangement of the dental model desired at the end of all or part of the orthodontic treatment;

[0090] (B) For each tooth model,

[0091] - determining the distance corresponding to the difference between the contours of the tooth model in the initial model and in the final model;

[0092] - determining the shortest possible time for the tooth model to travel said distance, i.e. determining the shortest displacement time, or "minimum displacement time", for the tooth model to pass from its shape in the initial model to its shape in the final model;

[0093] (C) identifying the tooth model with the longest shortest displacement duration, or the “boundary tooth model”;

[0094] (D) determining a "first modified deformation scenario" according to which the initial model is transformed into the final model by displacement of the tooth model, and the first modified deformation scenario is determined so that for at least one first "slow" tooth model other than the boundary tooth model, a parameter is minimized, the parameter being selected from:

[0095] - the maximum value of the displacement speed achieved by the slow tooth model between the initial moment and the final moment, and / or

[0096] - a speed representing the displacement speed of the slow tooth model, preferably an average speed between an initial moment and a final moment, and / or

[0097] - the difference between the maximum value of the displacement speed and the minimum value of the displacement speed of the slow tooth model between the initial moment and the final moment, and / or

[0098] - An average change in the displacement speed of the slow tooth model between the initial moment and the final moment.

[0099] Preferably, an intermediate moment (preferably marking a time for a planned replacement of an orthodontic appliance), a first correction deformation scenario and said intermediate moment defining the first correction orthodontic treatment plan are determined, preferably by a computer.

[0100] The creation of the final model can be done by the dentist based on the initial model using a computer suitable for processing tooth models.

[0101] In one embodiment, the tooth arrangement between the initial model and the final model need not be determined in advance, for example, by comparing the initial model and the final model, a distance corresponding to the difference between the appearances of the tooth models in the initial model and the final model can be determined.

[0102] However, preferably, in step (B), a "base deformation scenario" of the dental arch is determined, preferably by computer, the base deformation scenario comprising a series of intermediate models that perform three-dimensional modeling of the dental arch at intermediate moments between an initial moment and a final moment, wherein the distance is determined according to the base deformation scenario, for example the distance is the distance traveled by one or more points of the tooth model according to the base deformation scenario; then

[0103] In step (C), a boundary tooth model is determined, preferably by computer, as the tooth model, which tooth model has the last tooth model whose shape is achieved in the final model according to the basic deformation scenario.

[0104] The basic deformation scenario and the intermediate moments form the “basic orthodontic treatment plan”.

[0105] It is not necessary to define base deformation scenarios in order to implement corrections, but pre-generation of base deformation scenarios significantly improves the reliability or “predictability” of the orthodontic treatment plan, i.e., it increases the probability that teeth will move according to the orthodontic treatment plan.

[0106] In one embodiment, to determine the base deformation scenario, the computer:

[0107] - determining a set of continuous elementary deformations that transform the initial model into the final model by displacement of the tooth model, each of which obeys a corresponding set of constraints;

[0108] - for each tooth model, said distance is determined from said set of elementary deformations, said distance preferably being the sum of elementary distances traversed by a point or points of the tooth model during elementary deformations.

[0109] The base deformation scenario and / or the displacement speed of the tooth model can be determined by the dentist using a computer suitable for processing the tooth model, for example by means of the "Treat" software described on the webpage https: / / en.wikipedia.Org / wiki / Clear_aligners#cite_note-invisalignsystem-10.

[0110] The base deformation scenario can be determined in step (b).

[0111] The displacement velocity can be calculated as follows:

[0112] - distances measured by comparing the initial model with the final model and / or distances determined according to a base deformation scenario, preferably according to step (b), and

[0113] - time intervals determined according to the duration of the treatment, preferably the time intervals determined according to step (c).

[0114] The first modified deformation scenario is preferably obtained by modifying the basic deformation scenario. This method can be advantageously used to modify a commonly defined basic orthodontic treatment plan, in particular for orthodontic treatment using a set of orthodontic aligners. In fact, such a plan is usually defined manually by a dentist using a computer by processing the tooth model from an initial model to a final model.

[0115] The dentist can also use software that provides transition and intermediate models, such as the "Treat" software. The dentist can then modify these models and the software will recalculate the intermediate moments accordingly.

[0116] The correction may alternatively be related to a computer autonomously determined base deformation scenario, as described in the first main aspect of the invention.

[0117] Corrections can be made autonomously by the computer.

[0118] Preferably, of all teeth modeled in the initial model, except the boundary teeth modeled by the boundary teeth model, the first slow-rate teeth are the most useful teeth for deceleration according to practicality criteria defined by the dentist and / or user and according to the basic orthodontic treatment plan.

[0119] The first slow tooth may be the tooth whose displacement speed is most critical to the health of the user.

[0120] For example, the first slow tooth may be the tooth whose displacement speed reaches the closest to a preset "acceptable" value, for example according to the basic orthodontic treatment plan, especially a value exceeding which would cause an unacceptable risk to the user's health.

[0121] Preferably, the method according to the second main aspect of the invention also has one or more of the following optional features:

[0122] The intermediate moments are the moments, preferably determined by a computer, at which the dentist plans to check the dental arch and / or modify and / or produce an orthodontic appliance, preferably plans to replace an orthodontic appliance.

[0123] - The first slow tooth is, among all teeth modeled in the initial model, except the boundary teeth modeled by the boundary tooth model, the tooth of the dental arch whose displacement speed is most critical for the user's health, ie the tooth whose rapid displacement poses the highest risk to the user.

[0124] - the method comprises, after determining the first modified deformation scenario, determining, preferably by computer, a second modified deformation scenario, said scenario reducing, preferably minimizing, the velocity parameter of the second slow teeth model, modeling the second slow teeth, excluding the boundary teeth model and the first slow teeth model, preferably reducing, preferably minimizing the maximum value of the displacement velocity reached by the second slow teeth model between the initial moment and the final moment, with the constraint that the boundary teeth model and the first slow teeth model follow the path defined by the first modified deformation scenario;

[0125] Preferably, the second slow-rate tooth is, of all the teeth modeled in the initial model, except for the boundary teeth and the first slow-rate teeth, the tooth on the dental arch that is most useful for deceleration according to a practicality criterion defined by the dentist and / or the user and according to the first orthodontic treatment correction plan, wherein the usefulness criterion is preferably the same as the usefulness criterion used to select the first slow-rate tooth.

[0126] - The second slow-moving tooth is the tooth whose displacement speed reaches the closest to a pre-set "acceptable" value according to the first orthodontic treatment basic correction plan, especially a value that is critical to the user's health.

[0127] The first modified deformation scenario and optionally the second modified deformation scenario are determined in the following manner:

[0128] - anatomical constraints, preferably specifying that the tooth model does not penetrate into adjacent tooth models, and / or the position of one or more points of the tooth model is contained within a shell defined around the tooth model, and / or the translation speed of the tooth model in one direction is less than an upper limit of the translation speed, and / or the rotation speed of the tooth model in one direction about an axis is less than an upper limit of the rotation speed; and / or

[0129] - orthodontic rules and / or clinical constraints imposed by the dentist, preferably prescribing the fixation of one or more tooth models, and / or prescribing technical constraints to be followed when moving a tooth model, and / or facilitating a displacement relative to other teeth, and / or

[0130] or specifying a movement sequence of the tooth models, and / or specifying a correct occlusion, and / or allowing or prohibiting tooth filing, i.e. allowing or prohibiting a tooth model from probing into an adjacent tooth model, and / or allowing limited tooth filing, i.e. limiting the extent to which a tooth model can protrude into an adjacent tooth model, and / or allowing or prohibiting the extraction of one or more teeth, and / or proposing a displacement speed of one or more teeth; and / or

[0131] - Required constraints proposed by the user, which take into account, for example, the user's needs, related to orthodontic treatment causing limited pain and / or limited duration and / or limited cost, and / or causing limited aesthetic impact and / or having minimum reliability, and / or requiring a limited wearing time of orthodontic appliances, in particular a maximum wearing time of orthodontic braces or archwire and brackets type orthodontic appliances, and / or a limited number of steps, in particular limiting the number of orthodontic braces required for orthodontic treatment related to a first correction deformation scenario, or optionally the number of orthodontic braces related to a second correction deformation scenario, and / or having a preset number of steps, and / or allowing or prohibiting tooth filing, and / or allowing limited tooth filing, and / or allowing or prohibiting the extraction of one or more teeth, and / or allowing or prohibiting the use of one or more auxiliary orthodontic appliances.

[0132] Typically, the method preferably includes, for each tooth model identified as a "slow tooth model" except the boundary tooth model, determining, preferably in sequence by a computer, a correction deformation scenario (a first correction deformation scenario for a first slow tooth, a second correction deformation scenario for a second slow tooth, and so on), each time with the constraint being based on a previously defined correction deformation scenario, and the boundary tooth model and the slow tooth model follow the path defined by the previously defined correction deformation scenario.

[0133] According to a first main aspect, the invention relates to a method for inputting information into a computer, in particular in a method for generating an orthodontic treatment plan for a dental arch, preferably according to the first or second main aspect of the invention, preferably at least inputting the required constraints, the input method comprising the following steps:

[0134] (01) A first user inputs first information into a computer, for example, into a first input field on a first page of a form displayed on a first screen of the computer;

[0135] (02) the computer analyzes the first information, and then prepares a second page form with a second input field and displays it on a second screen of the computer, so as to require the second user to enter the second information. Whether the second input field is displayed and / or the nature of the second information accepted by the second input field depends on the first information entered by the first user in the previous step;

[0136] (03) The second user inputs the second information into the computer through the second input field,

[0137] (04) Preferably, the computer uses the second information, and preferably also the first information, to define an orthodontic treatment plan and / or monitor the smooth progress of orthodontic treatment.

[0138] The second page form for inputting the second information may be a new page, or may be a modified version of the first page used in step (01) for inputting the first information.

[0139] According to the present invention, the table is a dynamic table.

[0140] As will be described in detail below in this specification, a dynamic form with one or more pages advantageously makes input more efficient than static form input. This is because it avoids laborious reading of input pages that are not suitable for the second user. Thus, the dynamic form speeds up the second user's input. It also limits the risk of input errors because it is easier to understand the situation.

[0141] The dynamic form closely guides the input, which advantageously allows the input to be made without assistance, in particular without the assistance of the dentist. In particular, the data input can be made remotely by the dentist, in particular via a mobile phone of the first and / or second user. For example, if several photos are to be acquired under different acquisition conditions, the form may require the input of a first photo and only after the first photo has been analyzed and verified, the input of a second photo.

[0142] Dynamic tables are particularly useful when the computer is integrated into a mobile phone. In practice it limits the information exchange with the mobile phone.

[0143] The second page of the table may be obtained by refreshing the first page of the table, or may be a new page of the table, especially when the first page of the table and the second page of the table do not belong to the same table, for example, when the display time of the first page of the table is more than 1 hour earlier than that of the second page of the table.

[0144] The first user may be the same person as the second user, in particular an individual undergoing or planning to undergo orthodontic treatment. The first and second screens are then preferably identical. For example, they may be the screens of the user's mobile phone.

[0145] The first user may be different from the second user. In particular, the first user may be a dentist and the second user may be an individual who is undergoing or planning to undergo orthodontic treatment. The first and second screens are then preferably different. For example, they may be a personal computer screen at the dentist's and a mobile phone screen of the user, respectively. This embodiment advantageously allows the first user to enter "professional" information that cannot be determined separately by the second user. For example, a dentist may analyze the dental condition of an individual, for example by analyzing oral photographs sent to him by the individual by mobile phone, and enter data characterizing this dental condition. The individual can then access a specific form suitable for his dental condition. More generally, this embodiment allows each user to enter information that is unknown to the other user, with the input interface of one user depending on the input made by another user.

[0146] Preferably, the method according to the third main aspect of the present invention also has one or more of the following optional features:

[0147] - the second input field accepts the second information only if it meets a criterion, for example if it belongs to a predefined range or a predefined list, said criterion being dependent on the first information;

[0148] - the format of the second input field depends on the first information;

[0149] the first information comprises at least one photograph, preferably at least one closed-mouth photograph and at least one open-mouth photograph and / or at least one panoramic and / or cephalometric X-ray, preferably at least one closed-mouth photograph, at least one open-mouth photograph, at least one frontal view photograph, one right-side view photograph and one left-side view photograph,

[0150] The right side and the left side are relative to the first user;

[0151] - the computer analyzes the one or more photos and displays or does not display the second input field and / or determines the nature of the second information accepted by the second input field according to the result of the analysis;

[0152] -After the first user inputs the first information, the computer analyzes the first information and adjusts the displayed page accordingly;

[0153] -The time of inputting the first information is less than 10 minutes earlier than the time displayed in the form on the second page;

[0154] -The first information and / or the second information are requirements extracted by the first and / or the second user, wherein the requirements expressed by the users relate to: the orthodontic treatment to be planned produces limited pain and / or limited duration and / or limited cost, and / or causes limited aesthetic impact and / or has minimum reliability, and / or requires limited time of wearing orthodontic appliances, and / or achieves predetermined orthodontic or therapeutic functional goals, in particular defining constraints to generate an orthodontic treatment plan according to the first and / or second main aspects of the present invention.

[0155] Preferably, only the input fields that need to be input are displayed. In other words, if input is not always required, the computer will ask the first user to determine whether the corresponding input field should be displayed.

[0156] For example, if the likelihood of benefiting from anesthesia depends on the second user's medical history, the computer may display an input field for the first user to indicate whether the second user has ever reacted to anesthesia before displaying a second input field for the second user to enter whether they consent to anesthesia, and only if the answer is "no" will the second input field be displayed for the second user to enter whether they consent to anesthesia.

[0157] In addition to one or more input fields, a form page usually has navigation buttons to allow displaying the previous or next page of the form, or exiting the form.

[0158] The first information and / or the second information may be of any nature, in particular a photograph of the dental arch, an X-ray film of the dental arch, data of planned or ongoing orthodontic treatment, a model of the dental arch or a view of a model of the dental arch or clinical instructions.

[0159] The first information and / or the second information may include information of the first and / or second user, such as data on the age or gender of the first user.

[0160] Preferably, they comprise photographs of the first user, preferably extraoral photographs, at least one dental arch photograph, preferably in the form of film. Preferably, the photographs comprise at least one open oral cavity photograph and at least one open oral cavity photograph. Preferably, the photographs comprise at least one frontal perspective photograph, one right side perspective photograph and one left side perspective photograph, the right side and the left side being relative to the user.

[0161] Preferably, the first information and / or the second information comprises a clinical order defining the number of teeth to be displaced and the numbers of teeth to be displaced and / or kept stationary.

[0162] Preferably, the first and / or second information comprises a definition of a treatment goal and / or a definition of a maximum number of orthodontic appliances for the orthodontic treatment to be planned.

[0163] The computer preferably includes a memory defining a set of conditional rules that directly or indirectly determine the second input field based on the first information.

[0164] For example, the conditional rule for directly determining the second input field of the second information based on the first information is: "If the age entered by the first user is less than 12 years old, the second input field is displayed, that is, asking the first user whether he has replaced all his deciduous teeth."

[0165] For example, a conditional rule that indirectly determines the second input field based on the first information is: "If the analysis of the dental arch photo of the first user shows the presence of calculus, then display the second input field, i.e., ask the first user whether he has undergone dental cleaning." In fact, the photo constituting the first information needs to be analyzed to determine whether calculus exists. The second input field will only be displayed if the analysis result requires the detection of calculus.

[0166] Preferably, the conditional rule also determines the representation form of the second input field, more generally determines the representation form of the object on the page containing the second input field. For example, the representation form may vary depending on the age of the first user.

[0167] Conditional rules can be arranged in the form of a decision tree.

[0168] In one embodiment, for each first information in a group of first information, the method includes a loop of steps (01) to (03), wherein the group of first information preferably includes more than 10, more than 50, more than 100 and / or less than 1000 first information, and whether the input field of step (02) of the loop is displayed and / or the nature of the input field of step (02) of the loop depends not only on the first information entered by the user in step (01) of the loop, but also on at least one first information and / or at least one second information entered in one or more previous loops.

[0169] The method preferably comprises a step (04).

[0170] The second input field can be in any format.

[0171] If a feature of one aspect of the present invention is technically compatible with another main aspect of the present invention, the feature may be applicable to the other aspect of the present invention.

[0172] In particular, features of the modification described in accordance with the first main aspect of the invention may be applicable to the second main aspect, and vice versa. In particular, when describing the two main aspects, certain terms such as "base deformation scenario" or "first modified deformation scenario" are used because they refer to similar objects and may refer to the same objects when the two main aspects are applicable. In particular, for these objects, features of the first main aspect of the invention may be applicable to the second main aspect, and vice versa.

[0173] The present invention also relates to:

[0174] - a computer program comprising program code instructions for:

[0175] - steps (b) and (c), preferably steps (a), (b) and (c), and optionally a first step (d) and preferably an additional step (d), and preferably a design operation of an orthodontic appliance for step (e), and / or

[0176] - step (C'), and preferably step (A') or (B'), preferably step

[0177] (A') and step (B') and step (C'), and / or

[0178] - step (02) of displaying a dynamic form according to the invention and preferably displaying an input of first information, and / or

[0179] - Steps (B), (C) and (D), and preferably (A),

[0180] When the program is executed by the computer:

[0181] - a computer medium on which such a program is stored, such as a memory or a CD-ROM, and

[0182] - a computer loaded with such a program,

[0183] - A kit comprising said computer and orthodontic appliance manufacturing equipment to implement step (e).

[0184] Preferably, the computer program includes program code instructions for automating all automatable operations.

[0185] Preferably, the computer program further comprises program code instructions for cutting the initial model into tooth models and / or determining a final model from the initial model.

[0186] The present invention also relates to a system comprising:

[0187] - a three-dimensional scanner capable of forming a "rough" model of the first user's dental arch, and

[0188] - A computer according to the invention, preferably optionally configured to transform said rough model into an initial model, optionally with the assistance of a dentist.

[0189] definition

[0190] "User" refers to any person who practices the method according to the present invention, whether or not that person is a patient.

[0191] "Dentist" means any dental practitioner in the broadest sense and specifically includes orthodontists and dentists.

[0192] "Complete orthodontic treatment" is treatment that aims to correct the arrangement of teeth on the dental arch to the user's desired final position. Orthodontic treatment that is part of complete orthodontic treatment is called "partial" orthodontic treatment. Unless otherwise specified, "orthodontic treatment" usually refers to either complete or partial orthodontic treatment.

[0193] Orthodontic treatment requires the use of one or more orthodontic appliances. Retainer treatment, which is intended to keep teeth in a permanent position, is not considered orthodontic treatment.

[0194] Orthodontic treatment is planned through a "treatment plan". Therefore, "orthodontic treatment" refers to the series of operations carried out in reality, while the "treatment plan" is the result of the orthodontic treatment design. Therefore, the treatment plan precedes the corresponding orthodontic treatment.

[0195] Orthodontic treatment with orthodontic appliances is the implementation of a treatment plan that defines, before orthodontic treatment, a model of the dental arch with the desired shape at various moments during orthodontic treatment. The generation of a treatment plan usually includes designing one or more orthodontic appliances and modeling them. Basavaraj Subhashchandra Phulari describes an example of appliance design in "History of Orthodontics". Thus, the treatment plan defines the models of the orthodontic appliances used, which are used to make the corresponding orthodontic appliances. Modeling of orthodontic appliances can be done automatically by a computer or manually by the dentist.

[0196] More specifically, a series of models of the user's dental arch (which present a continuous arch shape) and a corresponding series of orthodontic appliance models are typically determined, which allows orthodontic appliances to be manufactured so that each orthodontic appliance changes the shape of the dental arch from the shape presented by one arch model to the shape presented by the next arch model.

[0197] Therefore, each treatment plan "corresponds" to the orthodontic treatment, the dental arch models at the beginning and end of the relevant orthodontic treatment, and one or more orthodontic appliances during the implementation of the orthodontic treatment, wherein the orthodontic appliances are designed to make the shape of the dental arch consistent with the dental arch model at the end of orthodontic treatment.

[0198] An example of software that allows processing of tooth models and creation of treatment plans is the "Treat" program, as described on the web page https: / / en.wikipedia.org / wiki / Clear_aligners#cite_note-invisalignsystem-10. US patent US5975893A also describes the creation of treatment plans.

[0199] An “orthodontic appliance” is an appliance suitable for carrying out orthodontic treatment. Orthodontic appliances may be used for therapeutic or preventive treatment, as well as for cosmetic treatment.

[0200] The orthodontic appliance may be in particular an appliance of the archwire and bracket type, or an orthodontic brace, or a Carrière Motion type auxiliary appliance. The outer shape of the orthodontic appliance may in particular be determined to ensure its fixation on the teeth, but may also be determined according to the desired position of the teeth. More precisely, the shape is determined so that the orthodontic appliance exerts a stress when in the position of use, causing the treated teeth to tend to move towards their desired position.

[0201] A 3D scanner or "scanner" is a device that allows obtaining a model of the dental arch.

[0202] The "use position" is the position when an orthodontic appliance (e.g., an orthodontic brace) is fixed to a dental arch to treat the dental arch. Typically, the user can release the fixation of the orthodontic brace by simply pulling the brace.

[0203] "Computer" means an information processing device, which includes a set of several instruments, having information processing capabilities. Such a device may be integrated in particular into a scanner or a mobile phone, but may also be a PC-type computer or a server, for example a remote server of the user, such as a "cloud" or a computer located at the dentist's place.

[0204] Typically, a computer specifically includes a processor, a memory, a human-machine interface with a conventional screen, an Internet communication module, WIFI, or telephone network. A computer program configured to at least partially implement the method of the invention is loaded into the memory of the computer. The computer may also be connected to a printer.

[0205] In the method according to the invention, different computers communicating with each other can carry out the individual steps or, preferably, the same computer carries out all the steps. The computer is preferably integrated into the mobile phone.

[0206] "Computer form" means all pages displayed on a computer screen and allowing the user to enter information, ie, consisting of one or more pages.

[0207] A form is "dynamic" if it changes based on previously acquired information about the user, which is displayed on one or more pages that were previously displayed, such as through a dynamic form. It is therefore not predefined as a static questionnaire, which asks the same information in the same way regardless of previously entered information, especially information entered by the user.

[0208] The areas on a form page where users enter information into the computer are called "input fields."

[0209] For example, an input field could be:

[0210] -Multiple-choice questions, such as with checkboxes;

[0211] - text or number input box;

[0212] -Move cursor;

[0213] - Clickable buttons;

[0214] - An ordered set of buttons and / or checkboxes and / or checkboxes, e.g. Figure 8 The "teeth map" or "teethmap" shown.

[0215] The adjectives "first" and "second" are used to distinguish between the first page and the input field of the first page form. The first and second input fields can be different or the same, for example, if the first information only requires changing the appearance of the first input field.

[0216] "Model" refers to a three-dimensional digital model. The model consists of a set of voxels or "points". The model can be, for example, of .stl or .Obj, .DXF 3D, IGES, STEP, VDA or point cloud type. Advantageously, it is possible to observe such a model, called a "3D" model, at any angle.

[0217] The "dental arch model" is a three-dimensional digital model that presents the user's tooth arrangement. Preferably, the dental arch model also presents other organs of the oral cavity, especially the gums.

[0218] There is no limit to the number of points of the dental arch model. In one embodiment, the dental arch model, in particular the final model, contains only the points necessary to define the tooth arrangement.

[0219] A "tooth model" is a three-dimensional digital model of a tooth in a user's dental arch. The dental arch model may be cut to define a tooth model of at least a portion of the teeth, preferably a tooth model of all teeth represented in the dental arch model. Thus, a tooth model is a model in a dental arch model. Figure 3 An example of a view of a dental arch model cut into a tooth model 32 is shown, wherein only the tooth model is shown. There are computer tools to process the tooth model of the dental arch model. These tools allow constraints to be specified, in particular to limit the displacement of the tooth model to a practical displacement, in order to prevent, for example, adjacent tooth models from intruding into each other.

[0220] There is no limit to the number of points of a tooth model. In one embodiment, a tooth model contains only the points necessary to define its shape. In one embodiment, a tooth model contains points that may collide with other tooth models.

[0221] If the deformation scenario changes the position of the points of the tooth model of the initial model so that it is basically the same as the points of the tooth model of the final model at the final moment (or the transition model at the transition moment), then the points in the tooth model of the initial model are "matched" with the points in the tooth model of the final model (or the transition model).

[0222] According to the International Dental Federation's international convention, each tooth in the dental arch, and therefore each tooth model produced, has a pre-assigned "tooth number". The tooth numbers defined in this convention are given in Figure 4 .

[0223] A "markable point" is a point on a dental arch model or tooth model that can be identified, such as the top or cusp of a tooth, an interdental contact point, i.e., the point where a tooth contacts an adjacent tooth, such as the mesial or distal point of the incisal edge of a tooth, or the center point or "barycenter" of a crown.

[0224] "Cutting" the dental arch model into a "tooth model" is an operation that allows to define the teeth in the dental arch model (tooth model) and to render these teeth autonomously. There are computer tools to process the tooth model of the dental arch model. An example of software that allows to process the tooth model is the "Treat" program as described on the webpage https: / / en.wikipedia.org / wiki / Clear_aligners#cite_note-invisalignsystem-10.

[0225] When the dental arch model is cut into tooth models, other models, such as the gum model, can also be cut.

[0226] A "reference system" serves as a basis for marking points in space, in particular for measuring distances or measuring orientations or positions of points, for example on a dental model. For example, a reference system may be a three-dimensional coordinate system, such as an orthogonal coordinate system. In order to determine the arrangement of teeth in a dental arch model or the shape of teeth on a dental arch, a reference system fixed relative to the dental arch model is used. For example, the origin of the reference system may be located in the center of the user's mouth.

[0227] The "shape" of a tooth or tooth model refers to its position and orientation in a reference frame.

[0228] A "morphing scenario" is a set of transition models that are ordered in time. So it is a series of transition models. It can be thought of as a 3D movie showing how the dental arch model morphs in the space between the initial model and the final model.

[0229] The “fragmentation” of the deformation scenario consists in defining intermediate moments, i.e. specifying the moments when the deformation scenario occurs, the dentist examines the dental arch and / or modifies the orthodontic appliances, in particular the moments when orthodontic braces are replaced for orthodontic treatment with orthodontic braces, and / or the moments when orthodontic appliances need to be made.

[0230] An "orthodontic treatment plan" comprises a deformation scenario and intermediate moments defined for that deformation scenario.

[0231] A “step” is a period of an orthodontic treatment plan, defined as between the initial moment and the first intermediate moment, between two consecutive intermediate moments, or between the last intermediate moment and the final moment.

[0232] One phase usually consists of 2 to 150 steps. For example, after orthodontic treatment for a malocclusion, 2 or 3 orthodontic braces may be sufficient to correct a deviation or "relapse". A correction phase for a complex malocclusion may require dozens of orthodontic braces.

[0233] A "path" of a tooth model according to a deformation scenario is a set of continuous representations of the tooth model in a transition model of the deformation scenario. A path can be thought of as a 3D movie showing how the tooth model is displaced in space between an initial moment and a final moment. Thus, determining a deformation scenario by displacement of the tooth model comprises finding a set of paths for the tooth model of the dental arch.

[0234] The "movement capacity" of a tooth model defines the physiologically acceptable maximum value of the displacement speed of the tooth model.

[0235] Therefore, the physiologically acceptable maximum value of the tooth model speed refers to a value that, once exceeded, will cause a risk to the user's health (e.g., risk of tooth loosening). It depends on the nature of the teeth or the number of teeth. For example, the acceptable displacement speed of the incisors is greater than the acceptable displacement speed of the molars.

[0236] The physiologically acceptable maximum value of the tooth model speed is defined according to the number of teeth modeled, in particular based on statistical data. It can also depend on the user, for example taking into account the presence of a splint.

[0237] The physiologically acceptable maximum value of the velocity also depends on the type of movement considered and the direction of movement considered, such as outward or inward displacement. Preferably, a physiologically acceptable maximum value is defined for a plurality of displacement velocities.

[0238] The "displacement velocity" of the tooth model includes the translation velocity (eg, velocity vector modulus) and the rotation velocity.

[0239] To account for the different behaviors of teeth depending on the type of movement, displacement velocities may include:

[0240] - a point related to the tooth model, preferably a point related to the center of mass of the tooth model, the speed of translation along the various axes of a reference system fixed relative to the dental arch model, and

[0241] - The rotation speed of the tooth model about each of said axes.

[0242] In order to take into account the different behaviors of teeth depending on the direction of movement, the displacement speed may also include the translation and rotation speeds, while distinguishing the speed direction each time, for example, distinguishing between outward movement and inward movement.

[0243] The displacement speed of the tooth model corresponds to the expected displacement speed of the modeled teeth according to the orthodontic treatment plan.

[0244] The deformation scenario is "corrected" when reducing or minimizing a velocity parameter, which is preferably selected from:

[0245] - the maximum value of the displacement speed achieved by the slow tooth model between the initial moment and the final moment, and / or

[0246] - a speed representing the displacement speed of the slow tooth model, preferably an average speed between an initial moment and a final moment, and / or

[0247] - the difference between the maximum value of the displacement speed and the minimum value of the displacement speed of the slow tooth model between the initial moment and the final moment, and / or

[0248] - An average change in the displacement speed of the slow tooth model between the initial moment and the final moment.

[0249] A "representative velocity" of a tooth model is a velocity determined from one or more displacement velocities of the tooth model, for example the vector modulus of the translation velocity of the tooth model's center of mass, or the vector modulus of the rotation velocity of a markable point on the tooth model's surface.

[0250] A "representative distance" of the displacement of the tooth model is a distance calculated from the displacement of one or more points of the tooth model and / or one or more points associated with the tooth model (e.g. its centroid). An example of a representative distance is the length of the path traversed by the centroid of the tooth model according to the degeneration scenario. Another example of a representative distance is the Euclidean distance between the positions of the centroid of the tooth model in the final model and in the initial model.

[0251] "Correct occlusion" is the arrangement of the teeth of the two dental arches that allows acceptable contact between the two dental arches according to the rules of orthodontics. In particular, with correct occlusion, the tips of the teeth of the upper dental arch do not contact the tips of the teeth of the lower dental arch when the mouth is closed. The teeth of the two dental arches "interocclude", with the tips of the teeth of one dental arch penetrating into the alveoli or interdental spaces of the teeth of the other dental arch.

[0252] An "image" is a two-dimensional picture, such as a photograph or an image taken from a film. An image is made up of pixels.

[0253] "Dental arch image", "dental arch view", "dental arch representation", "dental arch scan" or "dental arch model" refers to an image, view, representation, scan or model of the whole or part of the dental arch, preferably showing at least 2 teeth, preferably at least 3 teeth, preferably at least 4 teeth. Figure 2 An example of a view of a dental arch model with 5000 points is shown.

[0254] “Meta-heuristic” methods are known optimization methods. They are preferably selected from:

[0255] - an evolutionary algorithm, preferably selected from the group consisting of evolutionary strategies, genetic algorithms, differential evolution algorithms, distribution estimation algorithms, artificial immune systems, Shuffled Complex Evolution path recombination, simulated annealing, ant colony algorithms, particle swarm optimization algorithms, taboo search and GRASP methods;

[0256] - Kangaroo algorithm, Fletcher and Powell method, sound effect method, random tunnel, restarted random walk algorithm, cross entropy method, and

[0257] - A hybrid approach of the above meta-heuristic methods.

[0258] A "statistical process" is a process which, when applied to a set of so-called "historical" data, allows the determination of an intrinsic characteristic of the set, such as the mean, standard deviation or median. Statistical processing tools are well known to those skilled in the art.

[0259] "Deep learning devices", also known as "deep learning" algorithms, are also well known in the art. They include "neural networks" or "artificial neural networks".

[0260] Those skilled in the art know how to select and train a neural network depending on the task to be performed.

[0261] In particular, the neural network may be selected from:

[0262] - Networks specialized for image classification, called "CNN" ("Convolutional Neural Network"), such as AlexNet (2012), ZF Net (2013), VGG Net

[0263] (2014), GoogleNet (2015), Microsoft ResNet (2015), Caffe: BAIR ReferenceCaffeNet, BAIR AlexNet, Torch:

[0264] VGG_CNN_S, VGG_CNN_M, VGG_CNN_M_2048, VGG_CNN_M_1024, VGG_CNN_M_128, VGG_CNN_F, VGGILSVRC-2014 16-layer, VGG ILSVRC-2014 19-layer, Network-in-

[0265] Network(Imagenet&CIFAR-10), Google: Inception(V3, V4),

[0266] -Networks specifically designed to locate and detect objects in images are called "object detection networks", such as R-CNN (2013), SSD (Single Shot MultiBox Detector: Object Detection network), Faster R-CNN (Faster Region-based Convolutional Network method: Object Detection network), Faster R-CNN (2015), SSD (2015), RCF (Richer Convolutional Features for Edge Detection) (2017), SPP-Net,

[0267] 2014, OverFeat (Sermanet et al.), 2013, GoogleNet (Szegedy et al.), 2015, VGGNet (Simonyan and Zisserman), 2014, R-CNN

[0268] (Girshick et al.), 2014, Fast R-CNN (Girshick et al.), 2015, ResNet (He et al.), 2016, Faster R-CNN (Ren et al.), 2016, FPN (Lin et al.), 2016, YOLO (Redmon et al.), 2016, SSD

[0269] (Liu et al.), 2016, ResNet v2 (He et al.), 2016, R-FCN (Dai et al.), 2016, ResNeXt (Lin et al.), 2017, DenseNet (Huang et al.), 2017, DPN (Chen et al.), 2017, YOLO9000 (Redmon and Farhadi), 2017, Hourglass (Newell et al.), 2016,

[0270] MobileNet (Howard et al.), 2017, DCN (Dai et al.), 2017, RetinaNet (Lin et al.), 2017, Mask R-CNN (He et al.), 2017, RefineDet (Zhang et al.), 2018, Cascade RCNN (Cai et al.),

[0271] 2018, NASNet (Zoph et al.), 2019, CornerNet (Law and Deng), 2018, FSAF (Zhu et al.), 2019, SENet (Hu et al.),

[0272] 2018, ExtremeNet (Zhou et al.), 2019, NAS-FPN (Ghiasi et al.), 2019, Detnas (Chen et al.), 2019, FCOS (Tian et al.),

[0273] 2019, CenterNet (Duan et al.), 2019, EfficientNet (Tan and Le), 2019, AlexNet (Krizhevsky et al.), 2012

[0274] - Networks specifically designed for generating images, such as Cycle-Consistent Adversarial Networks (2017), Augmented CycleGAN (2018), Deep PhotoStyle Transfer (2017), FastPhotoStyle (2018), pix2pix

[0275] (2017), Style-Based Generator Architecture for GANs (2018), SRGAN (2018).

[0276] This list is not intended to be limiting.

[0277] The training of a neural network consists in comparing it with a learning library containing information about two objects that the neural network should learn how to "match", ie connect them to each other.

[0278] Training may be performed starting from a learning base consisting of records, each record comprising a first object of a first type and a corresponding second object of a second type.

[0279] Alternatively, training can be performed starting from a learning library consisting of records, each record containing a first object of a first type, or a second object of a second type, but each record containing information about the type of object it contains. For example, such training techniques are described in the article "Unpaired image-to-image translation using cycle-consistent adversarial networks" by Zhu, Jun-Yan, et al.

[0280] The neural network is trained using these records so that it learns to provide a corresponding object of the second type based on any object of the first type.

[0281] The quality of the analysis performed by the neural network directly depends on the number of records in the training library. Preferably, the learning library contains more than 10,000 and / or less than 10,000,000 records.

[0282] Unless otherwise indicated, "including," "comprising," or "having" should be interpreted broadly and not restrictively.

[0283] BRIEF DESCRIPTION OF THE DRAWINGS

[0284] Other features and advantages of the present invention will be described by reading the following detailed description and referring to the accompanying drawings, in which:

[0285] -[ Figure 1 ] Figure 1 Schematically illustrating a method according to a first main aspect of the invention;

[0286] -[ Figure 2 ] Figure 2 An example of a model with 5000 points obtained using a scanner integrated into a mobile phone is shown;

[0287] -[ Figure 3 ] Figure 3 An example of a dental arch model cut into a tooth model is shown, the part number of the tooth model being 32 (only the tooth model is shown);

[0288] -[ Figure 4 ] Figure 4 The tooth numbering used in the dental field is shown;

[0289] -[ Figure 5 ] Figure 5 Schematically illustrating a method according to a second main aspect of the invention;

[0290] -[ Figure 6 ] Figure 6 a table page schematically showing a method according to the third main aspect of the invention;

[0291] -[ Figure 7 ] Figure 7 Schematically illustrating a method according to a third main aspect of the invention;

[0292] -[ Figure 8 ] Figure 8 Examples of teeth diagrams available in a dynamic table according to the present invention are presented.

[0293] Further details and advantages of the invention will be found in the following indicative, non-limiting embodiments. DETAILED DESCRIPTION

[0294] The method according to the first and second aspects of the invention aims to generate an orthodontic treatment plan from an initial moment to a final moment.The method may plan a complete or partial (ie insufficient alone to achieve the user's desired appearance) orthodontic treatment.

[0295] Partial orthodontic treatment corresponds to a phase of complete orthodontic treatment, such as a phase of remoteness aimed at separating the teeth in order to be able to subsequently reposition them, or a phase of aligning the centre of mass of the teeth along the curve of the dental arch that carries them, or a phase of rotation of the teeth about their centre of mass.

[0296] In one embodiment, the method is performed several times during each stage of complex orthodontic treatment.

[0297] In step (A'), the computer determines the initial model of the first stage, the "first stage initial model". This model represents the dental arch before the complex orthodontic treatment begins. The computer cuts it into tooth models, just like step (a).

[0298] The computer, preferably a computer-assisted dentist, also determines the final model of the last stage, the "final stage end model", as in step (a). This model represents the desired dental arch at the end of the complex orthodontic treatment.

[0299] In step (B'), the computer or computer-assisted dentist determines the end-stage model of each stage by displacement of the tooth model until the penultimate stage, the end-stage model of the last stage having been determined in step (A').

[0300] The end-of-stage model of a stage presents the objectives to be achieved at the end of the stage. The beginning-of-stage model of a stage is the end-of-stage model of the previous stage.

[0301] In a preferred embodiment, the computer defines the phase end models, from the first phase initial model to the last phase end model, but excluding the last phase end model that may appear. To this end, the orthodontic rules required to define these phases are learned in advance.

[0302] For example, in the previous example, after determining the tooth model that needs to be displaced, by comparing the first stage initial model and the last stage final model, the computer can displace the tooth model from the first stage initial model until they are separated by a sufficient distance so that their centers of mass can be aligned along the dental arch curve, and then they will rotate themselves so that the arch lines of the tooth model are basically aligned. The resulting model can be regarded as the first stage final model.

[0303] Starting from this model, the computer can then displace the tooth models so that they align along the curve of the dental arch. The resulting model can be considered the second stage final model.

[0304] Starting from this model, the computer can then rotate the tooth models so that their surfaces align along the arch line. The resulting model can be considered the final model of the third stage.

[0305] To search for the final model, the computer can use optimization algorithms, in particular simulated annealing.

[0306] In step (C'), the computer implements the method according to the first and / or second aspects of the present invention for each stage. Each time the method is implemented, the initial model used is the initial model of the stage, and the final model used is the final model of the stage.

[0307] An example of the method according to the first embodiment will now be described in detail. In this example, it is considered that there is only one stage of orthodontic treatment that needs to be planned.

[0308] In step (a), an initial model and a final model are generated.

[0309] Initial Model

[0310] The initial model is a three-dimensional digital model that presents the teeth that need to be displaced according to the expected arrangement of the teeth on the dental arch at the beginning of orthodontic treatment (i.e. the initial moment).

[0311] Preferably, the initial model is created based on measurements of the user's teeth or a physical model of their teeth (eg a plaster model).

[0312] An initial model is then preferably made within one month before the initial moment, preferably within 2 weeks before the initial moment, preferably within one week before the initial moment, so that it correctly matches the tooth arrangement at the beginning of orthodontic treatment.

[0313] The initial model is preferably created by professional equipment, such as a 3D scanner, preferably by a dentist, such as an orthodontist or an orthodontic technician. In an orthodontic clinic, a physical model of the user or his teeth can advantageously be arranged in a precise position and the professional equipment can be perfected. Thus a very accurate initial model is obtained. The initial model preferably provides information about the positioning of the teeth with an error of less than 5 / 10 mm, preferably less than 3 / 10 mm, preferably less than 1 / 10 mm.

[0314] In one embodiment, the tooth arrangement may have evolved between the time when the initial model was generated and the initial time. For example, the initial model may have been generated more than one month or more than two months before the initial time. The initial model is then updated, preferably deformed, preferably one or more tooth models are displaced, to match the tooth arrangement at the initial time. In particular, the initial model may be deformed to match one or more dental arch photographs taken within a week before the initial time.

[0315] The number of points of the initial model is preferably greater than 5,000, 10,000 or 15,000 and / or less than 100,000. It thus accurately represents the teeth. However, if the number of points is high, the computer processing speed of the initial model may be slowed down.

[0316] In one embodiment, the initial model contains less than 5000 points, or even less than 1000 points, which allows to speed up the implementation of the method. In particular, the time required to generate deformation scenarios, in particular the time required to generate deformation scenarios according to the first optimization algorithm described below, depends on the number of points in the initial model used to determine the first distance.

[0317] An initial model comprising less than 5000 points, i.e. a "coarse model", can in particular be obtained by simplifying a fine initial model, preferably acquired with a 3D scanner, for example comprising 10,000 or 20,000 points. The number of points of the initial model is preferably greater than 1000 and / or less than 500,000.

[0318] In one embodiment, the simplification of the initial model is achieved by randomly selecting points on the surface of the initial model. In one embodiment, the initial model contains all points that match points of the final model. Preferably, the initial model only contains points that match a corresponding point of the final model. In one embodiment, the initial model has no points whose position may be affected by orthodontic treatment.

[0319] In one embodiment, the initial model contains only a set of points that are just enough to define the position and orientation of each tooth model in space. For example, each tooth model contains only three unaligned markable points. Preferably, the set of points also contains points that may collide with adjacent tooth models, for example, points of the tooth model in the initial model that are close to the adjacent tooth model.

[0320] A match can be established between the tooth models in the fine model and the coarse model, which allows, if the deformation scenario was generated using the coarse initial model and thus contains a coarse transition model, to reconstruct a high-precision fine transition model, which can be used, for example, for the production of orthodontic appliances.

[0321] In order to deform the initial model, it is cut to generate a three-dimensional digital model of each tooth, the "tooth model". The tooth model is then displaced.

[0322] Preferably, the initial model is also cut to generate a three-dimensional digital model of the gums, ie, an "initial gum model".

[0323] Final Model

[0324] The final model is a three-dimensional digital model that presents the teeth in use, arranged in the dental arch as they are desired at the end of orthodontic treatment, ie at the final point in the future. It is therefore a theoretical model.

[0325] The goal of the final model is to provide the necessary information to define the orientation and position of each tooth on the dental arch at the final moment. The final model may not be as accurate as the initial model. In practice, the position of a tooth model can be defined by the position of a markable point on the tooth model, for example by the position of its center of mass. The orientation of a tooth model can be defined by two non-parallel vectors, for example, their common origin is the center of mass of the tooth model. Therefore, three markable points, such as the center of mass and two points that are not aligned with the center of mass of the tooth model, are sufficient to define the shape of the tooth. Therefore, the final model can be composed of a set of data comprising, for each tooth model, three markable points of the tooth model.

[0326] For example, the article “Dense Representative Tooth Landmark / axisDetection Network on 3D” by Guangxin Wei, Zhiming Cui, Jie Zhu, Lei Yang, Yuanfeng Zhou, Pradeep Singh, Ming Gu, and Wenping Wang (https: / / arxiv.org / pdf / 2111.04212v2.pdf) describes the determination of tooth positions.

[0327] The final model can be obtained by deforming the initial model caused by the displacement of the tooth model.

[0328] It can usually be determined by the dentist through displacement of the model using the "Treat" procedure as described on the following webpage https: / / en.wikipedia.org / wiki / Clear_aligners#cite_note-invisalignsystem-10.

[0329] In a preferred embodiment, in step (a), the computer analyses the initial model and infers the final model from it. Thus, no manipulation of the tooth model is required to define the final model. However, in one embodiment, the dentist may propose constraints, for example based on the orthodontic treatment being considered.

[0330] In one embodiment, there is a "historical" database in the memory of the computer containing a set of records, each record being associated with a historical initial model and a historical final model. In particular, the historical initial model and the historical final model can be models showing the user's tooth arrangement at the beginning and end of the "historical" orthodontic treatment.

[0331] Therefore, computer analysis of the initial model may include:

[0332] - Search the database for the closest historical initial model, i.e. the shape of the initial model that is closest to the shape of the initial model for which the final model needs to be searched, and then

[0333] - selecting for said final model the historical final model associated with the closest historical initial model.

[0334] Therefore, the user's dental arch is assimilated to the closest historical initial model, and the relevant historical final model is considered to be available to the user.

[0335] The historical database may also be used to train one or more neural networks to provide the position and / or orientation of the tooth model in the final model. For example, it may provide:

[0336] - records as input, each record contains the tooth number and data of the historical user,

[0337] The data defines the appearance of the tooth with the number, and

[0338] - Records are output, each record containing a tooth number and data defining the ideal shape of the tooth with said number.

[0339] In particular, specialized networks can be used in the above-mentioned image classification.

[0340] In one embodiment, the computer converts the initial model into the final model using predefined rules. For example, the predefined rules may specify that the teeth in the final model must be aligned, specify the gaps between model vertices of adjacent teeth, or specify the orientation of each tooth.

[0341] In one embodiment, the initial model is analyzed to:

[0342] - determining a curvature baseline based on a dental arch curvature, such as a curvature of a curve connecting the centroids of the teeth, and a length of the dental arch, such as a length of the baseline;

[0343] - Determine the theoretical position and orientation of each tooth on said baseline according to predefined rules.

[0344] Algorithms that allow the determination of the baseline and the tooth contour are well known, in particular for panoramic images obtained by tomography. In particular, the mean square value can be used, the standard function of which is ax 4 +bx 2 +c=0.

[0345] For example, predefined rules may dictate how the teeth should be distributed and oriented along the baseline according to the length and curvature of the dental arch.

[0346] For example, the predefined rules may be obtained by statistical processing of historical data providing said distribution and orientation of "historical" teeth of historical dental arches of historical users in terms of length and curvature.

[0347] Advantageously, a computer can determine the final model very quickly without human intervention.

[0348] Algorithms that allow the comparison of the shapes of two models are well known. For example, the ICP (Iterative Closest Point) algorithm is known, which is described in particular in the Wikipedia online encyclopedia.

[0349] In a preferred embodiment, the initial model of the dental arch is cut to generate an initial gingival model and to confirm whether the arrangement of the tooth model in the final model is compatible with the initial gingival model. This confirmation can be done by the dentist and / or by a computer (autonomously or under the control of an operator such as the dentist). Preferably, it is confirmed whether the tooth model in the final model protrudes into the initial gingival model and / or whether a physiologically unrealistic gap occurs between the tooth model in the final model and the initial gingival model. In case of such protrusion or gap, the initial gingival model is converted into the final gingival model to eliminate the protrusion or gap.

[0350] In step (b), the computer determines a series of continuous deformations of the initial model to obtain the final model.

[0351] The models obtained by the successive elementary deformations before reaching the final model are called “transition models”. Therefore, each transition model presents the tooth arrangement at the corresponding transition moment.

[0352] The number of transition models is preferably greater than 3, preferably greater than 10 and / or less than 1000. Preferably, it is determined that no point on the dental arch model between two consecutive transition models has a displacement of more than 1000 μm, 500 μm or 100 μm, and / or that at least one point on the dental arch model between two consecutive transition models has a displacement of more than 10 μm, 50 μm or 100 μm. The accuracy of the deformation scenario is improved.

[0353] Each basic deformation should follow a set of constraints. The constraints include:

[0354] - anatomical constraints, such as stipulating that during the basic deformation process, the tooth model cannot penetrate into the adjacent tooth model, and / or the position of one or more points of the tooth model should be contained in a shell defined around the tooth model, and / or the translation speed of the tooth model in one direction should be kept below a specified upper limit of the translation speed, and / or the rotation speed of the tooth model in one direction around an axis should be kept below a specified upper limit of the rotation speed;

[0355] - preferably, orthodontic rules and / or clinical constraints imposed by the dentist, for example specifying the fixation of one or more tooth models during the basic deformation process, for example taking into account gum problems, bone density problems, the presence of one or more implants, and / or requiring technical constraints to be followed when moving the tooth model, for example taking into account the available orthodontic instruments, and / or facilitating displacement relative to other teeth, and / or requiring a sequence of movement of the tooth model, and / or requiring a correct occlusion, and / or allowing or prohibiting tooth filing (English

[0356] "stripping"), and / or allowing limited tooth filing, and / or allowing or prohibiting the extraction of one or more teeth, and / or stipulating that the displacement of one or more teeth is as uniform as possible, that is, limiting the variation of the displacement speed of one or more teeth as much as possible, and / or stipulating an upper limit on the displacement speed of one or more teeth; and / or stipulating the existence of one or more stages and / or the execution order of the appendices;

[0357] - preferably, required constraints proposed by the user, taking into account e.g. the needs of the user, relating to orthodontic treatment causing limited pain and / or limited duration and / or limited cost, and / or a limited number of steps and / or having a pre-set number of steps, and / or allowing or prohibiting tooth filing, and / or allowing limited tooth filing, and / or allowing or prohibiting extraction of one or more teeth, and / or allowing or prohibiting the use of one or more auxiliary orthodontic appliances.

[0358] The set of constraints imposed on the basic deformations may vary depending on the dental arch model that produces the basic deformation (or "model to be deformed", i.e., the initial model or transition model). For example, the possible positions and orientations of the tooth model may be restricted by the presence of adjacent tooth models, whose positions and orientations may themselves change at each basic deformation.

[0359] In one embodiment, the set of constraints contains constraints that may lead to basic deformations that are not directly applicable in reality. In particular, the set of constraints may allow a limited penetration of a tooth model into an adjacent tooth model. The basic deformation thus obtained, in order to be operable, requires filing of one or two teeth whose tooth models penetrate each other. Preferably, the computer informs the dentist of the necessity of performing such filing.

[0360] Part or all of the constraints may be determined based on information input by the user, preferably through a dynamic table. Figure 6 An example of a page of such a form is shown. Figure 7 A dynamic table according to the third main aspect of the invention is shown.

[0361] In particular, the user can specify:

[0362] - the maximum number of orthodontic appliances used for orthodontic treatment, i.e. the maximum number of intermediate moments;

[0363] -The number of teeth that must remain immobile during orthodontic treatment, specifically by clicking on the boxes with these tooth numbers.

[0364] Figure 8 An example of a tooth diagram is presented. The user can select one or more teeth by clicking on the icons of the tooth numbers on the tooth diagram.

[0365] Figure 6 The page presented still allows the user to specify treatment goals, which the computer can use to determine the dental arch model at the end of orthodontic treatment.

[0366] The determination of the basic deformations and deformation scenarios is preferably done by a computer program called "generator", which is implemented by a computer.

[0367] Preferably, the computer cuts the initial model. Cutting the initial model to determine the model of the organ it represents is a well-known operation. Preferably, the initial model is cut so as to define at least the part representing the teeth, i.e. the "tooth model". The tooth model can be defined as described, for example, in the international patent application PCT / EP2015 / 074896.

[0368] To determine the basic deformation, the generator displaces the tooth model while respecting the set of constraints. The basic deformation comprises, and preferably only comprises, displacements of the tooth model.

[0369] Even if the tooth model is randomly displaced, the determination of the basic deformation is fast, especially when the number of points in the initial model is small. However, the determination of the deformation scenario may take a long time.

[0370] To speed up the search for deformation scenarios, the generator can implement rules used by dentists to generate orthodontic treatment plans. For example, it can

[0371] - facilitating the displacement of the tooth model along the shortest or fastest path towards the final model, taking into account one or more tooth models, for example by defining the path as the sum of paths traversed by a plurality of tooth models, preferably taking into account all tooth models, and

[0372] -Deviate from this path only if a collision with an adjacent tooth model occurs.

[0373] Preferably, the generator implements a first optimization algorithm, preferably a meta-heuristic method, preferably an evolutionary algorithm, preferably a simulated annealing method. In particular, in the definition of the meta-heuristic method, the first optimization algorithm can be selected from the algorithms listed above.

[0374] The first optimization algorithm allows the following steps to be implemented:

[0375] (i) Create “test cases”, i.e. apply a set of consecutive “test cases” to the initial model

[0376] basic deformation, preferably entirely by displacement of the dental model, so as to obtain a "to be tested" dental arch model;

[0377] (iii) determining a first distance corresponding to the shape difference between the model to be tested and the final model;

[0378] (iii) comparing the first distance with a first threshold to obtain a first score for the scenario to be tested;

[0379] (iv) If the first score is insufficient, for example, higher than a preset minimum first score, modify the scenario to be tested and repeat step (i).

[0380] Therefore, the cycle of steps (i) to (iv) is repeated until the score of the scenario to be tested is satisfactory, that is, the model to be tested can be considered to be close enough to the final model. The scenario to be tested can then be regarded as a "deformed scenario".

[0381] In step (i), a scenario to be tested may be randomly generated.

[0382] The scenario is preferably created taking into account the scores obtained in the previous cycles, for example in order to avoid applying basic deformations that do not produce good scores. Preferably, the creation of the scenarios to be tested is guided by the rules used by dentists to generate orthodontic treatment plans. For example, the scenarios to be tested may be selected to favor displacement of the tooth models along the shortest path to the final model and deviate from this path only in case of collision with adjacent tooth models.

[0383] In step (i), the scenario to be tested may in particular be a scenario to be tested of a previous cycle, to which additional basic deformations are added. In other words, the model to be tested is obtained by applying additional basic deformations to the model to be tested of the previous cycle. Thus, the scenario to be tested is "extended" from one cycle to the next until an acceptable scenario is obtained. In one embodiment, this construction of deformation scenarios is stopped if the first distance becomes greater than the distance of the scenario to be tested previously determined, wherein the preset deviation may be zero.

[0384] In step (ii), the first distance is, for example, the sum of the Euclidean distances between the points in the model to be tested and the corresponding points in the final model.

[0385] In step (iii), the first score may be, for example, the inverse of the difference between the first distance and a first threshold. The first threshold may be zero, so that the cycle of steps (i) to (iv) results in a final model.

[0386] Preferably, the generator generates a plurality of deformation scenarios of the dental arch and then selects the scenario that minimizes the distance, which has an ideal deformation scenario, for example, causing the smallest total deformation. Such a deformation scenario is called an "optimal deformation scenario".

[0387] Still preferably, the generator implements a second optimization algorithm to search for optimal deformation scenarios. The second optimization algorithm is preferably a meta-heuristic method, preferably an evolutionary algorithm, preferably a simulated annealing method. In particular, in the definition of the meta-heuristic method, the second optimization algorithm can be selected from the algorithms listed above.

[0388] The second optimization algorithm allows the following steps to be implemented:

[0389] (i') creating a "to be tested" deformation scenario, preferably by means of a first optimization algorithm;

[0390] (iii) measuring a second distance corresponding to the difference between the deformation scenario to be tested and the ideal dental arch deformation scenario;

[0391] (iii') comparing the second distance with a second threshold to obtain a second score for the deformation scenario to be tested, where the second score may be, for example, the inverse of the difference between the second distance and the second threshold; (iv') if the second score is insufficient, for example, higher than a preset minimum second score, modifying the deformation scenario to be tested and repeating step (i').

[0392] Therefore, the cycle of steps (i') to (iv') is repeated until the score of the deformation scenario to be tested is satisfactory, that is, it can be considered that the deformation scenario to be tested is close enough to the ideal deformation model. The deformation scenario to be tested is the "optimal" deformation scenario.

[0393] The second distance may be, for example, the cumulative Euclidean distance traversed by a set of points of the initial model (e.g., all points of the initial model) in the deformation scenario to be tested. In an ideal deformation scenario, the Euclidean distance is preferably the minimum distance, so that the second threshold may be, for example, zero, and the second fraction is equal to the second distance. For at least one tooth model of the initial model, preferably at least two, preferably at least three tooth models of the initial model, preferably each tooth model of the initial model, the set of points preferably comprises one point, preferably more than one point, more than two points. The second distance may give a weight greater than the Euclidean distance traversed by certain points, for example, points on certain tooth models that present teeth whose displacements should be particularly limited.

[0394] If the second threshold is zero, the second distance may define a second score. Step (iii') is then useless. It is therefore optional.

[0395] Preferably, the second distance takes into account one or more requirements put forward by the user. For example, the user may have filled out a computer questionnaire in the computer to specify these requirements, such as specifying the importance he attaches to the speed of orthodontic treatment and / or the pain caused by orthodontic treatment (e.g., pain measured by a pain coefficient), and / or the importance he attaches to comfort during orthodontic treatment (e.g., measured by a comfort coefficient), and / or the importance he attaches to the cost of orthodontic treatment.

[0396] Comfort can specifically refer to the effect of orthodontic treatment on esthetics.

[0397] Therefore, in one embodiment, the second distance depends on the duration and / or pain factor and / or comfort factor and / or cost associated with the deformation scenario to be tested. In the ideal deformation scenario, the duration, pain factor and cost are preferably the lowest, so that the comparison basis of these criteria can be, for example, 0. In the ideal deformation scenario, the comfort factor is preferably the highest, so that the comparison basis of this criterion can be, for example, the possible maximum value of this factor.

[0398] The assignment of duration (or duration coefficient standardized for duration) and / or pain coefficient and / or comfort coefficient and / or cost (or cost coefficient standardized for cost) associated with the deformation scenario to be tested can be determined by the dentist or preferably by an evaluation module programmed in a computer, which implements rules usually used by dentists or rules determined by a computer through statistical processing. For example, the deformation scenario to be tested can be compared with historical dental arch deformation scenarios in a database in order to determine similar historical deformation scenarios and to use the information on duration, pain coefficient, comfort coefficient and / or cost.

[0399] The criteria (duration, pain factor, comfort factor, cost) of the historical arch deformation scenarios can be evaluated based on surveys completed by persons who have been treated according to the historical arch deformation scenarios and / or by dentists who performed these treatments.

[0400] The neural network can also be trained to assign a duration (or duration coefficient) and / or a pain coefficient and / or a comfort coefficient and / or a cost (or a cost coefficient) to a deformation scenario to be tested. In particular, in the above-mentioned image classification, a special network can be used, which is not trained to provide the probability of occurrence of different predefined categories, but is trained to provide values ​​from an infinite set of values ​​(i.e. continuous values). For training, a deformation scenario, or preferably only an initial model and a final model, can thus be provided as input, as well as the duration (or duration coefficient), pain coefficient, comfort coefficient or cost (or cost coefficient) associated with the deformation scenario.

[0401] For example, if:

[0402] -l i represents the distance traveled by point Pi of the tooth model of the dental arch according to the deformation scenario to be tested,

[0403] -k1 represents the weight of the duration factor, for example between 1 and 10, preferably provided by the user, depending on how much he values ​​the speed of orthodontic treatment,

[0404] -k2 represents the weight of the pain coefficient, for example, between 1 and 10, preferably provided by the user,

[0405] Depending on how much he values ​​the pain that orthodontic treatment may cause him,

[0406] - k3 represents the weight of the comfort factor, for example between 1 and 10, preferably provided by the user, depending on how much he values ​​comfort during orthodontic treatment,

[0407] -k4 represents the weight of the cost coefficient, for example, between 1 and 10, preferably provided by the user,

[0408] Depending on how much he values ​​the cost of orthodontic treatment,

[0409] C represents a demand factor taking into account the coefficients of duration C1 and / or pain C2 and / or comfort C3 and / or cost C4 of the deformation scenario to be tested, for example being equal to a polynomial function of these coefficients, for example equal to (k1*C1+k2*C2+k3*C3+k4*C4),

[0410] The second distance and / or the second score may be, for example:

[0411] - a set of N points "i" l i The sum of N is preferably greater than 10; or

[0412] - a set of N points "i" l i The sum is multiplied by the required coefficient.

[0413] In one embodiment, a deformation scenario, preferably an optimal deformation scenario, is first searched with a rough initial model, for example containing 100 points. The initial model, transition model and final model are then completed to confirm that there are no unacceptable collisions, i.e., collisions that cannot be eliminated by filing if filing is allowed. In the event of an unacceptable collision, i.e., if the computer finds that the deformation scenario includes mutual penetration of adjacent tooth models beyond acceptable limits, points are added to the initial model and the search is repeated using a simplified initial model of one cycle before the points were added.

[0414] In a preferred embodiment, the initial model of the dental arch is cut to generate an initial gingival model, and for each transition model in turn, it is confirmed whether the arrangement of the tooth model in the transition model is compatible with the following models:

[0415] - For the first transition model, is it compatible with the initial gingival model, or

[0416] - For the subsequent transition model, whether it is compatible with the gingival model in the previous transition model.

[0417] This confirmation can be done by the dentist and / or by a computer (autonomously or under the control of an operator such as the dentist). Preferably, it is confirmed whether the tooth model in the considered transition model protrudes into the initial gingival model and / or whether a physiologically unrealistic gap occurs between the tooth model and the gingival model. In case of such protrusion or gap, the gingival model is modified to eliminate the protrusion or gap. Thus, each transition model has a gingival presentation that is compatible with the arrangement of the tooth model.

[0418] In step (c), the computer determines the final moment of the scenario determined in step (b).

[0419] For this purpose, for example, the deformation scenario can be compared with historical dental arch deformation scenarios in a database, which database provides an associated treatment duration for each historical dental arch deformation scenario.

[0420] The duration of the scenario, and the final moment, may then be determined based on the duration of similar historical deformation scenarios, for example, selected to be equal to the duration of similar historical deformation scenarios.

[0421] The orthodontic treatment steps in the deformed scenario obtained in step (b) are marked with intermediate moments, which are the moments when the dentist plans to check the dental arch and / or modify the orthodontic appliances worn by the user and / or make orthodontic appliances for use by the user.

[0422] Modifying the orthodontic appliance worn by the user may include modifying the structure or shape of the appliance, or replacing it with a new orthodontic appliance. In one embodiment, the intermediate moment is the moment when the orthodontic appliance is planned to be replaced.

[0423] The intermediate time is preferably the time to plan the replacement of the orthodontic appliance.

[0424] The intermediate moments can be selected so that the time interval between two consecutive intermediate moments (preferably the time interval between any two consecutive intermediate moments) is within a preset range, preferably constant and / or equal to the longest usage duration of the orthodontic instrument, such as the usage duration of an orthodontic brace.

[0425] The transition model at the intermediate moment is called the "intermediate model".

[0426] The number of intermediate models is preferably less than 0.1 times the number of transition models. The number is preferably greater than 1 and / or less than 150.

[0427] In one embodiment, the number of intermediate models is equal to the number of transition models.

[0428] Preferably, the intermediate moments and the final moments are determined according to the movement of the tooth model, depending on the deformation scenario and the orthodontic appliance considered. In practice, the possibilities for displacement of the teeth by various translational and rotational movements are different, depending on the number of teeth considered and the orthodontic appliance considered. For example, depending on the capabilities of the polymer from which the orthodontic appliance is made, the inward or outward translation of the tooth between two steps may be limited to less than 0.1 mm, the rotation may be limited to less than 3° of rotation, flipping or twisting, etc. By knowing the necessary movements between the initial model and the final model, these constraints related to the characteristics of the orthodontic appliance allow the calculation of intermediate moments and final moments that are compatible with the orthodontic appliance and the orthodontic treatment.

[0429] There is no limitation on the manner of determining the intermediate and final moments. The rules commonly used by dentists to select the most appropriate intermediate moments can be implemented by a computer.

[0430] In a preferred embodiment, the computer performs the following method:

[0431] The initial model is cut into tooth models, the basic deformation of the deformation scenario being obtained by displacement of the tooth model in translation and / or rotation. Preferably, when cutting the initial model, the number of each tooth present in the initial model is identified by a label set by an operator or preferably by computer recognition of the shape (e.g. by a neural network). Such shape recognition performed by a computer is well known to those skilled in the art.

[0432] The displacement movement capabilities of a tooth vary depending on the nature of the tooth. In particular, the physiologically acceptable maximum value of the displacement, translation or rotation speed of the tooth in each direction of space depends on the number of the tooth. These displacement capabilities allow the definition of each set of constraints proposed for each basic deformation. In particular, these constraints can determine the upper limit of the translation and rotation displacement speed of each tooth model in each axis of a reference system (for example a rectangular coordinate system fixed relative to the user's skull). In particular, the upper limit of the displacement speed may be the physiologically acceptable maximum value of this speed.

[0433] The tooth displacement kinetic capacities can be determined by statistical analysis, in particular by analyzing panoramic radiographs and / or cephalometric radiographs of historical users. They can also be determined by analyzing panoramic radiographs and / or cephalometric radiographs of users using the method. In one embodiment, the tooth displacement kinetic capacities are determined by statistical analysis of historical data (i.e. data related to historical users), and the obtained values ​​are then refined for each user using the method, for example taking into account the bone density of each tooth of the user and / or the condition of their gums.

[0434] Therefore, according to a computer table that gives the upper limits of the translation and rotation displacement speeds in each axial direction of the reference system according to each tooth number, the computer can determine the upper limits of each tooth model.

[0435] Furthermore, for a deformation scenario, the "path" of the tooth model includes all the shapes of the tooth model from the initial model to the final model, i.e. all the shapes in the initial model, the transition model and the final model. It is thus possible to determine the distance traveled in space by each point of the tooth model during the progression of the deformation scenario. It is also possible to determine the angular range traveled by each tooth model around each of the three axes of the reference system during the progression of the deformation scenario.

[0436] For each tooth model, considering that it displaces at the largest possible displacement speed while following the constraints, that is, reaching the upper limit of these speeds defined by the constraints as much as possible, the shortest time for the tooth model to change its shape from the initial model to the final model can be determined according to the deformation scenario.

[0437] The tooth model that requires the longest duration is called the "boundary tooth model" because the deformation scenario cannot be performed faster. This duration, i.e. the duration of the orthodontic treatment plan, can be added to the initial moment to determine the final moment and the time of each moment of the deformation scenario can be determined.

[0438] By analyzing the paths of the individual tooth models according to the deformation scenarios, preferably by a computer, a boundary tooth model may be defined. Alternatively, a boundary tooth model may be predefined, for example, because it is generally considered to be the boundary of an orthodontic treatment.

[0439] The deformation scenario is then fragmented so that the boundary tooth model can follow its path, wherein intermediate moments defining the fragments are determined according to the ability of the orthodontic appliance to implement the deformation scenario. For example, moments can be defined at which the orthodontic appliance worn by the user should be adjusted so that the boundary tooth model can follow its path.

[0440] In particular, when orthodontic treatment is performed by orthodontic braces, the orthodontic braces only allow limited tooth displacement. For example, their limited elasticity may require that the displacement of any point of any tooth is always less than a limit of about 1 mm, or even always less than 0.5 mm. In other words, once a point of the tooth moves 1 mm after the placement of the orthodontic braces, the orthodontic braces must be replaced. Knowing the ability of the orthodontic braces to displace the teeth, it is possible to determine the intermediate moment when the orthodontic braces need to be replaced.

[0441] For example, in orthodontic treatment where the molars need to move 3mm and the canines need to move 4mm, the upper limit of the displacement speed of the molars is 1mm per month, and the upper limit of the displacement speed of the canines is 2mm per month. The displacement of the molars takes at least 3 months, and the displacement of the canines takes at least 2 months. Therefore, the molar model is a boundary tooth model, and the duration of orthodontic treatment is 4 months. If the orthodontic braces are adjusted to ensure that each tooth is displaced by 1mm, intermediate moments can be selected so that each time a displacement of 1mm after the previous moment (intermediate or initial moment) is marked. Therefore, if to is the initial moment, the intermediate moments are to+1 month, to+2 months, and to+3 months.

[0442] However, the orthodontic treatment plan so defined may dictate a very fast path for the molar model, which causes pain to the user and / or increased health risks to the user. The following step (d) and the second main aspect of the invention provide an answer to this problem.

[0443] In step (d), optionally, in a particularly advantageous embodiment, a generator, preferably a first and a second optimization algorithm, is used to search for new deformation scenarios, most preferably so-called "corrected" deformation scenarios, while for each basic deformation a new set of constraints is proposed.

[0444] - for the boundary tooth model, following the path defined by the base deformation scenario determined in step (b), and

[0445] - Apart from the boundary tooth model, ie the "slow tooth model", for at least one other tooth model a so-called speed parameter is preferably optimized.

[0446] Preferably, the new set of constraints stipulates that the upper limit of the displacement speed is lower than the displacement speed obtained according to the orthodontic treatment plan in step (c). In other words, this set of constraints stipulates that the speed of the slow tooth model modeled for the "slow teeth" cannot reach the maximum value allowed by the properties of the other teeth. For example, the upper limit of one or more displacement speeds of the slow teeth is stipulated to be lower than the upper limit required by the orthodontic treatment plan obtained in step (c).

[0447] Correction advantageously allows for improved treatment predictability, ie, an increased consistency between the orthodontic treatment plan and its subsequent implementation in the user's mouth.

[0448] Preferably, the speed variation of the slow teeth during the displacement process during treatment is limited, that is, the difference between the highest and lowest speeds reached during treatment is reduced. To this end, the computer also specifies one or several minimum speeds of one or several speeds of the slow teeth model, that is, the lower limit of the speed.

[0449] Preferably, the computer calculates at least one average speed of the slow tooth model based on the deformation scenario obtained in step (c), such as the average speed of a certain point translation or rotation around an axis, and the average speed during the duration of the orthodontic treatment plan obtained in step (c). Then, the set of constraints stipulates that the instantaneous speed change of the slow tooth model cannot exceed a certain percentage of the average speed, such as more than + / -20% or + / -10%. Advantageously, the displacement of the slow tooth model is more regular.

[0450] The deformation scenarios thus corrected advantageously limit the risks to the user.

[0451] If the new set of constraints dictates that the speeds of several slow tooth models cannot reach the maximum allowed by the properties of the teeth they model, corrections can be applied to multiple teeth simultaneously.

[0452] In a preferred embodiment, several slow tooth models are modified consecutively.

[0453] In each iteration of step (d), the computer adds new paths that follow the tooth model in the constraints, which paths were not proposed in the previous step (d). Preferably, the correction is performed tooth by tooth, preferably starting with the teeth whose rapid displacement is most likely to be harmful to the user. In other words, preferably, the first few correction operations involve rapidly displacing the teeth that are most harmful to the user.

[0454] Therefore, in the above example, as described above, by stipulating that the tooth model modeling the molars follows the path determined by the deformation scenario determined in step (b), and stipulating that the instantaneous speed of the tooth model modeling the canines shall not exceed 10% of the specified upper limit of the canines at any time, the generator can search for the modified deformation scenario, preferably the optimal modified deformation scenario. Then, as described above, by stipulating that the tooth models modeling the canines and the molars follow their respective paths determined according to the previous modified deformation scenario, and stipulating that the instantaneous speed of the tooth model modeling, for example, the incisors shall not exceed 10% of the specified upper limit of the incisors at any time, the generator continues to search for the modified deformation scenario, preferably the optimal modified deformation scenario.

[0455] The corrections for each tooth can be updated. If the correction is unsuccessful, the constraints on the speed can be lowered, for example limiting the speed variation to less than 10% of the average speed. It is also possible to repeat the previously implemented corrections by lowering the speed constraints on these previous corrections.

[0456] In one embodiment, a computer implements an optimization algorithm to test several sets of constraints to be imposed on the basic deformation and derive the best modified deformation scenario, i.e., the maximum value achieved for the speed of the slow tooth model is as low as possible. The size of the possible speed range is advantageously reduced to a minimum.

[0457] The computer can also or alternatively present various correction deformation scenarios to the dentist so that the latter can select the correction deformation scenario he wants. The dentist's selection criteria can also be programmed into the computer so that the computer can select the deformation scenario.

[0458] After step (c) and possibly step (d), in step (e), the intermediate model is used to design and manufacture one or more orthodontic appliances, such as one or more orthodontic braces. The design can be done by a computer or by a dentist. The manufacture can be done by any suitable manufacturing equipment.

[0459] It is now clear that the invention allows a very fast implementation of a partial or complete orthodontic treatment plan. Tests have shown that a deformation scenario can be determined by the computer in less than 10 minutes, which is then fragmented by the computer to obtain a high-quality treatment plan that meets the user's requirements. Speed ​​correction also allows limiting the risks to the user's health.

[0460] Correction method

[0461] The above-mentioned correction method can be advantageously extended to a method comprising steps (A) to (D), such as Figure 5 shown.

[0462] In step (A), in order to generate or collect the initial model and the final model, it is preferred to operate according to step (a).

[0463] In step (B), the definition of the measurement distance of the tooth model can be arbitrary.

[0464] For example, after superimposing the initial and final models to incorporate the stationary parts of the dental arch, it is possible to measure:

[0465] - the Euclidean distance between a point on the initial model (particularly a labelable point, such as a centroid) and the corresponding point on the final model;

[0466] - The accumulated Euclidean distances between several points (preferably labelable points) of the initial model and the corresponding points of the final model.

[0467] A distance corresponding to the difference in the tooth model shape between the initial model and the final model, such as the sum of the Euclidean distances between points of the tooth model in the initial model and corresponding points of the tooth model in the final model, advantageously limits the calculations used to search for the boundary teeth. In one embodiment, the first revised deformation scenario is not previously determined for any deformation scenario.

[0468] After superimposing the initial model and the final model in order to merge the stationary part of the dental arch, the distance travelled by one or more points, preferably markable points, can be measured, for example based on a basic deformation scenario between the model and the final model, preferably a basic deformation scenario defined according to the first main aspect of the invention.

[0469] The distance covered by a set of points on the tooth model according to a basic deformation scenario, such as step (d), is more complex because of the need to define said basic deformation scenario, preferably according to step (b). However, it is more accurate and advantageously limits the risk of errors when determining the boundary teeth.

[0470] The distance measurement is preferably performed autonomously by a computer.

[0471] The travel time of said distance of the tooth model can be roughly estimated, for example, by dividing the measured distance of the tooth model by a prescribed constant speed of said tooth model.The speed assigned to the tooth model is preferably determined according to the number of the modeled teeth and / or according to the physiological likelihood of displacement of the modeled teeth.

[0472] In an advantageous embodiment, the speed assigned to the tooth model varies with the moment considered. In particular, it may increase starting from the initial moment, for example 5 days from the initial moment, and / or decrease towards the estimated final moment, for example 5 days before the estimated final moment. Preferably, it is lower at the moments close to the initial moment and the estimated final moment.

[0473] The constant speed may be a representative speed of one or more displacement speeds of one or more points of the tooth model. It may be, for example, the vector modulus of the translation speed of the center of mass of the tooth model.

[0474] The travel time of the tooth model distance can be estimated more accurately. For example, the speed of the tooth model can be variable, in particular depending on the nature of the displacement considered and therefore on the displacement considered during the change in the shape of the tooth model in the initial model and the final model. The path of the tooth model can be determined by establishing a deformation scenario according to step (b).

[0475] For example, the basic duration between two consecutive contours of the tooth model can be determined by dividing the basic distance that the tooth model travels between the two contours by the determined speed of the basic distance. The travel time of the distance, which is equivalent to the contour difference of the tooth model in the initial model (initial contour) and the final model (final contour), can be the sum of the basic times determined between the various consecutive contours from the initial contour to the final contour.

[0476] The travel time of the distance is preferably done autonomously by a computer, ie without human intervention, preferably by the computer that carried out the previous step.

[0477] In step (C), the durations determined for each tooth model are then compared and the boundary tooth model associated with the longest duration is then retained. The displacement of the modeled boundary teeth determines the shortest possible duration of the orthodontic treatment.

[0478] The duration associated with the boundary tooth model defines the duration of the orthodontic treatment. This duration can be added to the initial moment in order to define the final moment.

[0479] This duration is preferably accomplished autonomously by a computer, preferably by the computer that performs the preceding steps.

[0480] In a preferred embodiment, for each tooth model and each type of movement (mesotropy / exosseotropy, proximal / distalization, lingual / vestibular displacement, flip, twist, and rotation), the distance to be traveled between the initial and final contours is calculated and divided by the maximum speed. The longest duration determines the boundary tooth model.

[0481] In step (D), the computer determines a first modified deformation scenario, preferably minimizing a so-called speed parameter.

[0482] Preferably, the computer determines a first modified deformation scenario to reduce, preferably minimize, a maximum value of at least one displacement speed achievable by at least one tooth model between an initial moment and a final moment, excluding a boundary tooth model or "first slow model".

[0483] The first slow tooth model models a "first slow tooth". The first slow tooth is preferably a tooth of the dental arch whose displacement speed is most critical to the health of the user, that is, a tooth whose rapid displacement creates the highest risk to the user, among all teeth modeled in the initial model, except for the boundary teeth modeled by the boundary tooth model. In one embodiment, the computer determines a first corrective deformation scenario to slow down all tooth models except the boundary tooth model.

[0484] Regardless of which embodiment, step (D) is preferably repeated while changing the slowed-down tooth model each time, requiring that each time step (D) is performed, the tooth model that has been slowed down in the previous step (D) follows the path defined in the previous step (D), as described in step (d).

[0485] The order in which the dental patterns are successively slowed down is preferably determined based on practical criteria defined by the dentist and / or the user.

[0486] After step (D), the method may comprise a step (e) of designing and manufacturing at least one orthodontic appliance, in particular an orthodontic brace, according to the first revised orthodontic treatment plan.

[0487] Example

[0488] In step (A), a computer collects an initial model of the user's dental arch obtained by scanning with an optical scanner.

[0489] The final model is determined by the dentist either computer-assisted or computer autonomously.

[0490] In steps (B) and (C), the computer-assisted dentist or autonomous computer searches for the basis deformation scenarios between the initial model and the final model, as described in step (b), i.e. the path of each tooth model. Then, based on the path of the tooth model (for determining the distance traveled) and the kinematics (for determining the travel time of the distance), the boundary tooth model and the final moment are determined.

[0491] Alternatively, the computer-assisted dentist or an autonomous computer, does not determine the base deformation scenario, but determines the boundary tooth models by comparing the distance between the initial shape and the final shape of the individual tooth models.

[0492] Once the boundary tooth models are identified, the method preferably attempts to move the other tooth models as slowly as possible.

[0493] In step (D), the computer-assisted dentist or an autonomous computer selects a "slow speed tooth model", preferably a tooth model whose slow speed is most useful for the user's health and / or best meets the user's requirements.

[0494] To determine the first modified deformation scenario, the computer searches for a set of continuous basic deformations that transform the initial model into the final model at the final moment by displacement of the tooth model and minimize the speed parameter of the slow tooth model. The computer preferably implements a conventional optimization algorithm, preferably a meta-heuristic method, preferably selected from the methods described above.

[0495] In particular, the cost function to be minimized may be the maximum displacement reached by the slow tooth model between the initial moment and the final moment. The speed may be determined as the maximum instantaneous speed between these moments, which may be calculated by dividing the distance of the tooth model between the two contours by the time interval between the two contours.

[0496] In a substantially equivalent manner, the optimization can also be implemented by defining a set of constraints, which are imposed on the basis of the basic deformations and which stipulate that the instantaneous speed (for the displacement speed) between two consecutive basic deformations is less than a given value. The computer then searches for a deformation scenario that complies with these constraints and then, if the search is successful, reduces the given value. Thus, the computer can iteratively determine the minimum value of the upper limit of the displacement speed between the initial moment and the final moment, which allows the deformation scenario to be defined. This deformation scenario is then the first modified deformation scenario.

[0497] Preferably, step (D) is then repeated for other slow models in sequence, with priority being given to the tooth model whose slowing down is most useful for the user's health and / or best meets the user's requirements.

[0498] An intermediate time can be defined in terms of the effectiveness or in terms of the orthodontic appliance used for the orthodontic treatment, preferably at the end of the method.

[0499] In a preferred embodiment, when determining the modified deformation scenario, the outer shape of the tooth model at certain moments is specified.

[0500] In particular, for determining the first modified deformation scenario, all constraints prescribe the shape of the boundary tooth model. The prescribed shape is preferably a "transition" shape in the transition model of the basic deformation scenario, preferably a shape at an intermediate moment.

[0501] Similarly, in order to determine the second modified deformation scenario when performing step (D) for the second time, all constraints specify the shape of the boundary tooth model and the first slow tooth model. The specified shape is preferably the "transition" shape in the transition model of the first modified deformation scenario, preferably the shape at the middle moment. When continuing to repeat step (D), proceed in a similar manner.

[0502] Preferably, steps (B) to (D) are autonomously performed by a computer.

[0503] In one embodiment, revisions are implemented to complement an existing orthodontic treatment plan.

[0504] The dental technician or dentist defines the orthodontic treatment plan using a computer, preferably in a conventional manner, for example using the Treat software, by moving the tooth model from the initial tooth model to the desired shape at the end of the orthodontic treatment. He thus determines intermediate moments, in particular intermediate moments for changing orthodontic appliances, final moments and "conventional" deformation scenarios, including intermediate models of the dental arches at intermediate moments.

[0505] Based on these data, preferably determined in a conventional manner, the computer can implement steps (B) to (D), preferably autonomously. The dentist or technician thus has a solution that allows him to perfect the orthodontic treatment plan he has established.

[0506] It is now clear that the method according to the invention allows the computer to expand the path of the tooth model as much as possible in the time interval between the initial and final moments, that is, to correct the displacement of the tooth model as much as possible by slowing down the instantaneous displacement speed of the tooth model as much as possible.

[0507] Note that the present invention is not limited to the embodiments described above.

Claims

1. A method for generating an orthodontic treatment plan for a user's dental arch, the method comprising the following consecutive steps: (a) generating or acquiring an "initial" model which three-dimensionally represents the dental arch at an initial moment, the initial model being cut into tooth models, and generating or acquiring a "final" model showing the dental arch in the "final" arrangement of the dental model desired at the end of the orthodontic treatment; (b) determining by computer a set of continuous basic deformations, wherein the basic deformations transform the initial model into the final model by displacement of the tooth model, wherein each of the basic deformations follows a respective set of constraints, and the model obtained by continuous basic deformations is called a "transition model", and the set of continuous transition models is connected into a "basic deformation scenario"; (c) determined by a computer, - Duration, i.e. from the initial moment, the deformation of the dental arch is achieved according to the deformation scenario, until the final moment when the final arrangement is obtained; as well as - intermediate moments between the initial moment and the final moment of the dental arch deformation according to the basic deformation scenario, said intermediate moments being the moments when the dentist plans to check the dental arch and / or modify and / or produce an orthodontic appliance, The basic deformation scenario and the intermediate moments define the orthodontic treatment plan, referred to as the "basic orthodontic treatment plan".

2. A method according to the preceding claim, wherein in step (a), the computer determines the final model from the initial model.

3. A method according to the preceding claim, wherein in step (a), in order to determine the final model, the computer - analyzing the shape of the initial model to determine the curvature and length of the dental arch and defining a baseline having said curvature and length, then, - for each of a plurality of dental models, determining the position and orientation of said dental model relative to said baseline, preferably according to predefined rules and / or by assimilating the dental arch of the user to a historical dental arch similar to the dental arch of the user.

4. The method according to the preceding claim, wherein before step (a), the predefined rules are determined by statistical processing of historical data.

5. A method according to any one of the preceding claims, wherein at the start of step (c), the computer - for each tooth model, determining the closest moment to the initial moment that the tooth model can reach, its appearance in the final model or "path end moment", according to the basic deformation scenario determined in step (b); - Determine, among all tooth models, the tooth model whose path end point is farthest from the initial time, i.e., the "boundary tooth model"; - Setting the final time as the path end time of the boundary tooth model.

6. A method according to the preceding claim, wherein the computer preferably determines the path end moment of the dental model, preferably the path end moment of each dental model, by dividing the distance representing the displacement of the dental model in the basic deformation scenario by the speed representing the movement ability of the dental model.

7. The method according to any one of the preceding two claims, after step (c), comprising the following step (d): (d) determining, by the computer, a new deformation scenario, referred to as a "first revised deformation scenario", wherein The boundary tooth model follows the path defined by the base deformation scenario determined in step (b), and At least one speed parameter is optimized, The first revised deformation scenario and the intermediate moments define a new orthodontic treatment plan, referred to as the "first revised orthodontic treatment plan".

8. The method according to the preceding claim, wherein the speed parameter is selected from: - the maximum value of the displacement speed achieved by the slow tooth model between the initial moment and the final moment, and / or - the difference between the maximum value of the displacement speed and the minimum value of the displacement speed of the slow tooth model between the initial moment and the final moment, and / or - An average change in the displacement speed of the slow tooth model between the initial moment and the final moment.

9. The method according to any one of the two preceding claims, comprising, after said first step (d), one or more consecutive additional steps (d), each of said additional steps (d) comprising determining by a computer an additional modified deformation scenario, wherein - the boundary tooth model follows the path defined by the base deformation scenario determined in step (b), and - in a step (d) preceding said additional step (d), said slow tooth model follows a path defined by said modified deformation scenario determined in said previous step (d) or said previous step (d), respectively, Since the additional modified deformation scenario is determined to optimize at least one between the initial time and the final time at least one speed parameter of an "additional" slow tooth model (different from the slow tooth model in the previous step (d)), The additional corrective deformation scenarios and the intermediate moments define an orthodontic treatment plan, referred to as an "additional orthodontic treatment correction plan".

10. A method according to any one of the three preceding claims, wherein when claim 9 is applied, the slow tooth model in the first step (d) or the additional step (d) is selected based on the criterion of usefulness to the dentist and / or the user, respectively, preferably based on the risk to the user's health caused by applying the basic deformation scenario or the orthodontic treatment correction plan of the previous step (d).

11. The method according to any one of the preceding claims, after step (c), or after the first step (d) when claim 7 is applicable, or after the additional step (d) when claim 9 is applicable, comprises the following step (e): (e) designing and manufacturing at least one orthodontic device according to the present orthodontic treatment plan obtained in step (c), or according to the first revised orthodontic treatment plan when claim 7 is applicable, or according to the additional revised orthodontic treatment plan when claim 9 is applicable.

12. A method according to the preceding claim, wherein - the orthodontic device is an orthodontic brace, and the intermediate time is specifically the time when the orthodontic brace is planned to be replaced, or - the orthodontic appliance is a kit comprising an orthodontic archwire and brackets for fixing the orthodontic archwire to the teeth, and the intermediate moment is in particular a moment when the replacement of the archwire and / or one or more brackets is planned.

13. A method according to any one of the preceding claims, wherein the set of constraints comprises user-proposed requirement constraints.

14. A method according to any one of the preceding claims, wherein the computer displays a dynamic form adapted to input at least a portion of the information required to define the set of constraints.

15. A method according to any of the preceding claims, wherein the set of constraints allows a limited penetration of a tooth model into an adjacent tooth model, the extent of the penetration being determined by the possibility of filing at least one tooth modelled by the tooth model in order to compensate for the penetration.

16. A method according to any one of the preceding claims, wherein in step (b), the computer implements an optimization algorithm to determine the basic deformation scenario, which better meets one or more requirements put forward by the user to clarify the user's emphasis on the speed of orthodontic treatment, and / or the pain caused by orthodontic treatment, and / or the comfort during orthodontic treatment, and / or the cost of orthodontic treatment and / or the aesthetic impact of orthodontic treatment and / or the reliability of orthodontic treatment.

17. A method according to any one of the preceding claims, wherein in step (b), the computer - search for deformation scenarios with a coarse initial model containing less than 5000 points, obtained by simplifying a fine initial model containing more points than the coarse initial model, and then - adding points to the transition model of the deformation scenario and to the final model, then, - determining whether, in the rough deformation scenario in which the transition model and the final model have been completed, the tooth models collide unacceptably, and - In case of unacceptable collisions, adding points to the rough initial model and re-performing the search using the rough initial model with the added points.

18. A method for generating a complete orthodontic treatment plan for a user's dental arch, wherein the complete orthodontic treatment consists of a number of consecutive partial orthodontic treatments, each partial orthodontic treatment corresponding to a stage of the complete orthodontic treatment, the method comprising the following consecutive steps: (A') generating or acquiring a first "beginning" model representing the dental arch at the beginning of the first stage of complete orthodontic treatment, the first model being cut into tooth models, and generating or acquiring a final "end of stage" model presenting the dental arch arranged in the desired dental model at the end of the last stage of the complete orthodontic treatment; (B') for each stage from the first stage to the penultimate stage, determining, preferably by a computer or computer-assisted dentist, a corresponding end of stage model presenting the dental arch arranged in the desired dental model at the end of the stage; (C') for each stage, implementing a method according to any one of the preceding claims, The initial model is the model at the beginning of the stage, and the final model is the model at the end of the stage.

19. A computer having loaded therein a program comprising program code instructions for executing: - steps (b) and (c), preferably steps (a), (b) and (c), and optionally the first step (d) when claim 7 is applicable, or the additional step (d) when claim 9 is applicable, and / or - step (C') and preferably the last step (A') of the method according to claim 18 or (B'), and preferably step (A') and step (B'), At this time, the program is executed by the computer.

20. A computer according to the preceding claim, wherein the program instruction code is adapted to determine the final model from the initial model, preferably according to claim 3 or claim 4, and / or when claim 11 is applicable, to design the orthodontic appliance.

21. A system comprising - a three-dimensional scanner capable of forming a "rough" model of the first user's dental arch, and - A computer according to any of the two preceding claims, the rough model being used as an initial model, or the computer being configured to transform the rough model into an initial model, either by the computer alone or with the assistance of a dentist.

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