Method for acquiring a model of a dental arch

Abstract

The invention relates to a method for acquiring at least one image of at least one dental arch of a user (U) by means of a mobile telephone (12') and an acquisition tool (31') having an acquisition head (32') provided with a camera (33'), in which method the acquisition head: - acquires the image and transmits the image to the mobile telephone, or - acquires a signal and transfers the signal to the mobile telephone in order that the mobile telephone generates the image from the signal, autonomously or with the aid of a computer with which the mobile telephone is in communication, the method including, after the acquisition step, an analysis of the image so as to define the dental situation of the user and / or to check the proper implementation of an ongoing active or passive orthodontic treatment.

Description

[0001] Description

[0002] Title: METHOD FOR ACQUIRING A MODEL OF A DENTAL ARCH

[0003] Technical field

[0004] The present invention relates to a method for acquiring a model of a user's dental arch and a computer program for implementing this method.

[0005] State of the art

[0006] It is advisable for everyone to have their teeth checked regularly, in particular to verify that the position and / or shape and / or appearance (or "texture") of their teeth is not changing unfavorably.

[0007] During orthodontic treatment, this unfavorable development may lead to a change in treatment. After orthodontic treatment, this unfavorable development, called "relapse," may lead to a resumption of treatment. Finally, more generally and independently of any treatment, everyone may wish to monitor any possible movements and / or changes in the shape and / or appearance of their teeth.

[0008] Traditionally, check-ups are performed by an orthodontist or dentist, who alone have the appropriate equipment. These check-ups are therefore expensive. Furthermore, the visits are restrictive. Finally, the professional scanners available are accurate, but require specific skills. They are traditionally used on the patient, for intraoral acquisition, or on a mold of the patient's arches, for extraoral acquisition.

[0009] Furthermore, US 15 / 522,520 describes a method which allows, from a simple photograph of the teeth taken by the user at an updated instant, to accurately evaluate the movement and / or deformation of the teeth since an initial instant. To this end, a digital three-dimensional model of the user's dental arch is created at the initial instant, preferably with a professional scanner. This initial model is then cut out so as to define a tooth model for each tooth. Finally, the tooth models are moved so as to transform the initial model of the dental arch so that it corresponds as closely as possible to the photograph. This method makes it possible to obtain a model representing the arch at the updated instant with excellent precision, without the user having to move for a scan of his teeth. This model can then be compared to the initial model to check the positioning and / or shape of the user's teeth.

[0010] This process is convenient for the user, but requires at least one appointment to acquire the initial arch model. It then requires heavy computer processing to cut the initial model and then deform it.

[0011] There is therefore a need for a method allowing monitoring of a user's dental situation remotely, as described in US 15 / 522,520, but which is even more practical for the user and faster to implement.

[0012] An objective of the present invention is to address, at least partially, this problem.

[0013] Summary of the invention

[0014] The invention provides a method for acquiring a model of at least one dental arch of a user, said method comprising the following steps: a) at an updated time, acquisition, preferably extraoral, with a portable scanner, by the user, of a digital three-dimensional model of said arch, or "acquired model", and optionally cutting out the model of the arch so as to isolate a part of the model of the arch, preferably a tooth model, so as to obtain an "updated model", the updated model thus being able to be the acquired model or the part of the acquired model isolated by cutting out, the object represented by the updated model being called "updated object".

[0015] As will be seen in more detail in the remainder of the description, the inventors have discovered that it is possible to use a portable scanner to produce, preferably extraorally and without any particular precautions, a model of an arch or a tooth of sufficient quality to be used in orthodontics. Such a method seemed incompatible with the acquisition of a sufficiently complete and precise model.

[0016] Advantageously, the acquisition can be carried out by the user himself, which opens up a wide range of applications. In particular, the acquisition no longer requires a trip to a dental care professional. In addition, a method according to the invention allows an analysis of the user's dental situation more quickly than according to the methods of the prior art. In particular, no construction of an arch model from photos is required. Generally speaking, 3D models of dental arches are conventionally acquired intraorally, with a 3D optical scanner, an intraoral acquisition allowing the sensor to be very close to the arch, and therefore to provide highly precise information.

[0017] Extraoral (or "extrabuccal") acquisition devices, i.e. in which the acquisition sensor, in particular the sensor of a camera or a photo device, is not introduced into the user's mouth, are recent and use photos to deform an initial model obtained with a conventional 3D optical scanner. The computer processing necessary for this deformation is expensive.

[0018] It is the inventors' merit to have tested a portable scanner, preferably extraoral, in particular a laser remote sensor, and to have discovered that such a scanner allows the patient to acquire a good quality model of his dental arches himself. Advantageously, no initial model, for example acquired at the start of orthodontic treatment, needs to be acquired, then be deformed from the images acquired by the scanner. The processing of the images acquired by the scanner allows, in fact, following the techniques conventionally used for 3D optical scanners, to directly obtain a model of the dental arch.

[0019] In an advantageous embodiment, the portable scanner is of low precision. It is sufficient to note the spatial position of a few notable points of the arch to create an updated model. Advantageously, the acquisition of a low-precision model is possible with limited and portable technical means. A low-precision model also requires little memory to be stored. It can easily and quickly be transmitted remotely, for example by radio waves.

[0020] Preferably the portable scanner

[0021] - is integrated into a mobile phone for so-called extraoral acquisition, or

[0022] - includes a mobile phone and an acquisition tool comprising an acquisition head capable of being inserted into the user's mouth, which

[0023] - acquires the acquired model, preferably by means of a laser remote sensor, and transmits it to the mobile phone, or

[0024] - acquires a signal and transfers it to the mobile phone so that said mobile phone generates the acquired model from said signal, autonomously or with the help of a computer with which said mobile phone is in communication. Preferably, the mobile phone transmits the acquired model and / or the updated model to a dental care professional, preferably by radio, preferably at a distance greater than 100 m, or greater than 1 km, or greater than 10 km and / or less than 50,000 km from the user.

[0025] An analysis method according to the invention may also include one or more of the following optional characteristics:

[0026] - in step a), the updated model is processed electronically to correct it, the correction possibly involving a modification of the updated model or a replacement of the updated model with a correction model;

[0027] - in step a), the updated model is compared with a correction model so as to obtain a measure of a difference in shape between the updated model and the correction model, then

[0028] - the updated model is modified so as to reduce said difference in shape, preferably so as to minimize said difference in shape, preferably by means of a metaheuristic method, in particular chosen from the methods listed below, preferably by simulated annealing, or

[0029] - depending on the said measure, the updated module is left unchanged or the updated model is replaced by the correction model;

[0030] - in step a), the updated model is submitted to a trained neural network to make a digital three-dimensional model presented to it as input more realistic;

[0031] - the updated object is said arch of the user or a tooth of said arch;

[0032] - the correction model is a model

[0033] - obtained, at a time different from the updated time, by a scan of said updated object, or

[0034] - representing said updated object with a theoretical form, preferably resulting from a simulation, or

[0035] - a model of an object representative of a set of individuals, said object being of the same type as the updated object, preferably an arch or a tooth, for example a typodont or a tooth from a typodont; - the correction model is:

[0036] - an updated model of the object obtained by scanning, preferably with a portable scanner or with a professional scanner, preferably at a time earlier than 2 weeks, 4 weeks, 6 weeks, 2 months, 3 months and / or less than 12 months, or less than 6 months before the updated time, or

[0037] - a model of the updated object, which simulates the shape of said updated object as anticipated for the updated instant and which, preferably, was produced at a time earlier than 2 weeks, 4 weeks, 6 weeks, 2 months, 3 months and / or less than 6 months before the updated instant, or

[0038] - a model of the updated object, which simulates the shape of said updated object as anticipated for a “correction” instant, subsequent or prior to the updated instant, the time interval between the updated and correction instants preferably being greater than one week, preferably greater than 2 weeks, 4 weeks, 6 weeks, 2 months and / or less than 6 months, said model having preferably been produced more than 2 weeks, more than 4 weeks, more than 6 weeks, more than 2 months or more than 3 months before the updated instant, or

[0039] - a historical model chosen from a historical library containing more than 1,000 historical models representing objects of the same type as the updated model, said choice preferably being guided so that the historical model chosen is the historical model presenting the greatest proximity in form to the updated model, or

[0040] - a model obtained by statistical processing of the historical models of said historical library, preferably in such a way that the model obtained by statistical processing is representative of a population of individuals;

[0041] - the historical library only includes historical models that meet the same classification criteria as the updated model, for example relating to individuals with at least one characteristic in common with the user, for example the same age and / or the same sex and / or the same pathology and / or following the same or similar orthodontic treatment;

[0042] - in step a), the updated model is corrected by inputting the updated model to the input of a neural network trained to correct models, preferably chosen from the neural networks listed in the detailed description of step iv) below; and / or - in step a), the updated model is corrected by following the following steps: i) creating a historical library comprising more than 1,000, preferably more than 5,000, preferably more than 10,000 historical models, each historical model modeling an object of the same type as the updated object, for example modeling an arch or a tooth if the updated model models an arch or a tooth, respectively, and assigning to each historical model a value for a classification criterion; ii) analyzing the updated model, so as to determine the value of said classification criterion for the updated object;(iii) searching the historical library for a historical model having the same value for said classification criterion and presenting maximum proximity to said updated model, or “optimal model”; (iv) modifying the updated model based on information relating to the optimal model, the modification possibly involving a replacement of the updated model by the optimal model;

[0043] - in step a), the acquired model is divided up so as to define a plurality of tooth models, then for each tooth model considered as an updated model, a cycle of steps i) to iv) is carried out in which the optimal model determined in step iv) is arranged so as to replace, in the acquired model, said tooth model, which advantageously makes it possible to reconstitute a high-precision arch model from an acquired low-precision model;

[0044] - in step a), the updated model is corrected by following the following steps: i') definition of:

[0045] - a first certain zone made up of points of the updated model representing a part of the patient, for example a tooth, with an accuracy greater than 90%, preferably greater than 95%, preferably greater than 99% or “first certain points”, and

[0046] - a first uncertain zone, constituting the 100% complement of the updated model; ii') extrapolation of the first certain zone, from the first certain zone alone, to define, in the region of the first uncertain zone, a first reconstituted zone, then definition of: - a second certain zone consisting of the points of the first uncertain zone separated from the first reconstituted zone by a distance less than a threshold distance, or "second certain points"; and

[0047] - a second uncertain zone, constituting the 100% complement of the first uncertain zone; iii') extrapolation of the set consisting of the first and second certain zones, from the set alone, to define, in the region of the second uncertain zone, a second reconstituted zone, then replacement of the second uncertain zone by the second reconstituted zone, so as to obtain a cleaned updated model;

[0048] - in step a), the updated model is corrected by submitting the updated model to a trained neural network by providing it with raw models of objects of the same type as the updated object as input, and said raw models made hyperrealistic as output;

[0049] - in step a), the updated model is processed electronically to simplify it;

[0050] - the portable scanner is integrated into a mobile phone or includes a mobile phone and an acquisition tool comprising an acquisition head capable of being inserted into the user's mouth, the acquisition tool being in communication with the mobile phone to transmit the acquired model or the updated model;

[0051] - the acquisition head is connected to the mobile phone, preferably via Bluetooth® or cable;

[0052] - the mobile phone is used to transmit, by radio, the acquired model or the updated model, preferably to a dental care professional, and in particular to an orthodontist, and / or to a computer processing center, preferably for the implementation of steps b) and / or c);

[0053] - the portable scanner is a laser remote sensor, in English lidar, for "light detection and ranging"; in step a), the portable scanner projects a structured light directly onto the patient's teeth and acquires different photo images; - in step a), the user modifies the angulation of the portable scanner, preferably by moving the portable scanner relative to the patient's teeth, preferably horizontally and / or vertically, preferably with the mouth open and the mouth closed;

[0054] - in step a), the user separates his lips and / or his cheeks to make his teeth visible to the portable scanner, then acquires the acquired model, preferably extraorally, that is to say without making the portable scanner penetrate, even partially, into his mouth;

[0055] - preferably, the user implements a spreader and / or a portable scanner support to improve the quality of the acquired model;

[0056] - in step a), the portable scanner is immobilized on a support comprising a rim, the rim being inserted between the lips and teeth of the user;

[0057] - the support comprises a tubular spacer which defines an oral opening, said rim extending to the periphery of the oral opening;

[0058] - in step a), the user modifies the angulation of the portable scanner, preferably by moving the support relative to the patient's teeth, preferably horizontally and / or vertically, preferably with the mouth open and the mouth closed, keeping the edge of the support between the user's teeth and the user's lips;

[0059] - in step a), the model acquired with the portable scanner is cut so as to define a plurality of tooth models, then each of said tooth models is successively corrected and / or simplified, preferably as described above;

[0060] - the method comprises, after step a), the following step: b) determining at least one value of a dimensional parameter of the updated model, or “dimensional value”, and / or an aspect parameter of the updated model, or “aspect value”;

[0061] - in step b), more than two dimensional values ​​are defined, preferably enough dimensional values ​​to define a position in space of at least one point of the updated model, preferably more than 10, more than 100, more than 500 points of the updated model; the dimensional parameter is chosen from - a dimension of the updated model; - a distance of a remarkable point of the updated model with respect to a reference frame, preferably fixed with respect to the updated model, preferably a reference model arranged, like the updated model, in a standardized configuration, and

[0062] - a parameter derived from one or more dimensions of the updated model and / or one or more distances from one or more notable points of the updated model relative to said reference system;

[0063] - the appearance parameter is chosen from a color, a reflectance, a transparency, a reflectivity, a tint, a translucency, an opalescence, an index on the presence of tartar, dental plaque or food on the tooth;

[0064] - to determine a said dimensional value, a distance is measured between a point of the updated model and a reference model arranged, like the updated model, in a standardized configuration;

[0065] - the reference model is preferably

[0066] - an updated model of the object obtained by scanning, preferably with a portable scanner or with a professional scanner, preferably at a time earlier than 2 weeks, 4 weeks, 6 weeks, 2 months, 3 months and / or less than 6 months before the updated time, or

[0067] - a model of the updated object, which simulates the shape of said object as anticipated for the updated instant and which, preferably, was produced at a time prior to the updated instant by more than 2 weeks, 4 weeks, 6 weeks, 2 months, 3 months and / or less than 6 months, or

[0068] - a model of the updated object, which simulates the shape of said object as anticipated for a reference instant, later or earlier than the updated instant, the time interval between the updated and reference instants being preferably greater than one week, preferably greater than 2 weeks, 4 weeks, 6 weeks, 2 months and / or less than 6 months, said model having preferably been produced more than 2 weeks, more than 4 weeks, more than 6 weeks, more than 2 months or more than 3 months before the updated instant, or

[0069] - a historical model chosen from a historical library containing more than

[0070] 1,000, preferably more than 10,000, preferably more than 100,000 historical models representing objects of the same type as the updated object, said choice preferably being guided so that the historical model chosen is the historical model having the greatest proximity in form to the updated model, or

[0071] - a model obtained by statistical processing of the historical models of said historical library, preferably in such a way that the model obtained by statistical processing is representative of a population of individuals;

[0072] - the method comprises, after step b), the following step: c) use of the dimensional value and / or the appearance value for:

[0073] - detect or evaluate a position or shape of a tooth and / or an evolution of a position or shape of a tooth and / or a speed of evolution of a position or shape of a tooth, and / or

[0074] - detect or evaluate a position or shape of an orthodontic appliance and / or a change in a position or shape of an orthodontic appliance and / or a speed of change in a position or shape of an orthodontic appliance, and / or

[0075] - measure an evolution in the shape of the patient's teeth between two dates, and / or

[0076] - in dentistry;

[0077] - in step c), the dimensional value and / or the aspect value are used for

[0078] - detect or evaluate a position or shape of a task or cavity:

[0079] - follow the eruption of a tooth, and / or

[0080] - detect a recurrence or abnormal position of a tooth, and / or

[0081] - detect an abrasion of a tooth, and / or

[0082] - follow the opening or closing of at least one space between two teeth, and / or

[0083] - control the stability or modification of the occlusion,

[0084] - follow the movement of a tooth towards a predetermined position, and / or

[0085] - detect or assess detachment of a ring or orthodontic splint,

[0086] - optimize the date of making an appointment with a dental care professional, and / or

[0087] - evaluate an orthodontic index, in particular chosen from the orthodontic indices listed in the definition of an orthodontic index below, preferably an orthodontic index indicating whether

[0088] - the user has reached an occlusion class No. I for the canines, and / or

[0089] - the user has reached an occlusion class No. I for the molars, and / or

[0090] - the patient's anterior spaces are closed, and / or

[0091] - all spaces resulting from tooth extraction are closed, and / or

[0092] - the user has a normal horizontal overhang, or "overjet" in English, preferably between 1 and 3 mm, and / or

[0093] - the user has a normal vertical overbite, preferably between 1 and 3 mm, and / or

[0094] - the midlines of the lower and upper arches are offset, and / or

[0095] - the user does not have a lateral shift of the upper arch in relation to the lower arch, and / or

[0096] - during the last two checks, no movement of a tooth was detected, and / or

[0097] - all temporary teeth have fallen out, or an orthodontic index quantitatively evaluating and / or evaluating the temporal evolution of:

[0098] - the occlusion class for the canines, and / or

[0099] - the occlusion class for molars, and / or

[0100] - the patient's anterior spaces, and / or

[0101] - spaces resulting from tooth extraction, and / or

[0102] - the horizontal overhang, and / or

[0103] - the vertical overhang, and / or

[0104] - the offset between the midlines of the lower and upper arches, and / or

[0105] - the lateral offset of the upper arch in relation to the lower arch, and / or

[0106] - the movement of a tooth during the last two check-ups, and / or

[0107] - assess the effectiveness of active orthodontic treatment, and / or

[0108] - measure the activity of an active orthodontic appliance; and / or

[0109] - measure a loss of effectiveness of a passive orthodontic appliance; and / or

[0110] - compare the positioning of the user's teeth, at the updated time, with that of said teeth as represented by a target theoretical model, preferably an intermediate model representing said teeth in an anticipated position, according to a treatment plan, for a final stage or for an intermediate stage of the orthodontic treatment, in English "intermediate set-up"; and / or

[0111] - assess the need to correct or adapt orthodontic treatment, for example by designing and manufacturing a new series of orthodontic aligners as part of orthodontic treatment with orthodontic aligners, or by changing the type of orthodontic treatment, for example from treatment with arches and attachments (“brackets” in English) to treatment with orthodontic aligners, or vice versa); and / or

[0112] - measure an evolution in the shape of the patient's teeth between two dates separated by the occurrence of a shock to the teeth or by the implementation of a dental device intended for the treatment of sleep apnea, or by the occurrence of a graft in the patient's mouth;

[0113] - in step a), the model acquired with the mobile phone is cut so as to define a plurality of tooth models, then a said step b) is carried out to define at least one dimensional value for each tooth model, defined as the updated model for said step b);

[0114] - in step a), the user acquires, preferably with the same mobile phone, said acquired model and one or more updated images, preferably color photos, preferably in realistic colors, and in step b), information relating to a dimension and / or the appearance of one or more objects, preferably teeth, represented on the updated image(s) is determined, then said information is used to complete and / or correct said dimensional value and / or said appearance value determined from the updated model;

[0115] - in step a), the acquired model has less than 500 points.

[0116] The invention also relates to:

[0117] - a computer program, and in particular a specialized application for a mobile phone, comprising program code instructions for the execution of step a), and preferably of step b), and preferably of step c), when said program is executed by a computer,

[0118] - a computer medium on which such a program is recorded, for example a memory or a CD-ROM, and

[0119] - a portable scanner, in particular incorporated in a mobile phone, into which such a program is loaded.

[0120] The invention thus relates to a portable scanner, preferably integrated into a mobile telephone, capable of implementing the acquisition in step a), and preferably one or more of the correction and / or simplification methods described in the present description, and preferably step b), and more preferably step c). Definitions

[0121] By "user" is meant any person for whom a method according to the invention is implemented, whether this person is ill or not, undergoing orthodontic treatment or not.

[0122] A “dental care professional” means any person qualified to provide dental care, which includes in particular an orthodontist and a dentist.

[0123] An “orthodontic treatment” is all or part of a treatment intended to modify the shape of a dental arch (active orthodontic treatment) or to maintain the shape of a dental arch, in particular after the end of active orthodontic treatment (passive orthodontic treatment).

[0124] Orthodontic indices are indices that allow, in a synthetic manner, to evaluate the shape and / or the evolution of the shape of the dental arches. They can be specific to one arch or to both arches together ("inter-arch" indices). Examples include: vertical overbite, horizontal overbite, crowding, in particular the Nance index, deviation of the inter-incisor midpoints, canine and / or molar occlusion classes, an irregularity index, in particular the Little index, anterior open bite, lateral open bite, posterior lingual cross bite, posterior buccal cross bite, ideal arch length, the presence or absence of interdental space, a leveling index of the curve of Spee, the presence of significant rotation, for example greater than 10°, on certain teeth, as well as combinations of these indices and their evolution.Examples of orthodontic indices are those used to define the American Board of Orthodontics' ABO Discrepancy Index.

[0125] An "orthodontic appliance" is a device worn or intended to be worn by a user. An orthodontic appliance may be intended for therapeutic or prophylactic treatment, but also for aesthetic treatment. An orthodontic appliance may be, in particular, an appliance with arches and brackets, or an orthodontic splint, or an auxiliary appliance such as Carrière Motion.

[0126] The term "arch" or "dental arch" refers to all or part of a dental arch. The term "image" refers to a two-dimensional digital representation, such as a photograph or a frame from a film. An image is made up of pixels.

[0127] By "model" we mean a digital three-dimensional model. A model is made up of a set of voxels. It typically includes a mesh made up of points connected by straight line segments, i.e., an assembly of triangles.

[0128] A "tooth model" is a three-dimensional digital model of a tooth. A model of a dental arch can be sliced ​​so as to define, for at least some of the teeth, preferably for all the teeth represented in the model of the arch, tooth models. The tooth models are therefore models within the model of the arch.

[0129] A “model of an arch” is a model representing at least a portion of a dental arch, preferably at least 2, preferably at least 3, preferably at least 4 teeth.

[0130] A model, especially a model of an arch or a tooth, is "hyperrealistic" when the observer has the impression of observing the modeled object itself. In particular, the colors of the model are those of the modeled object.

[0131] By “raw” model, we mean a model resulting from a scan and possibly corrected according to the invention, but whose color has not been modified to make it hyperrealistic.

[0132] The "type" of a modeled object, and in particular of the updated object, defines the nature of this object. The object can be in particular of the type "tooth" or "arch" or "gum". The object can also be a subgroup of teeth, for example the group of incisors or the group of teeth bearing one or more tooth numbers, or an arch subgroup, for example the upper arch.

[0133] A "classification criterion" is an attribute of a modeled object, in particular an arch or a tooth, that allows it to be classified. For example, the classification criterion may be an occlusion class, a range for a dimension (e.g., height, width, concavity, inter-canine distance, inter-premolar width, inter-molar width, arch length or arch splay, arch perimeter) of the modeled object, the age, sex, pathology, or orthodontic treatment of the person who owns the modeled object, an orthodontic index, in particular one chosen from the orthodontic indices listed above, or a combination of these criteria.

[0134] Using a classification criterion allows, in particular, the selection of modeled objects that have similar or identical characteristics. Advantageously, it allows the creation of a learning base well adapted to the object that a neural network is intended to process. For example, if a neural network is intended to correct tooth models representing teeth with the number 14, it is preferable to train it with a learning base containing only records relating to teeth number 14. The tooth number is then a classification criterion.

[0135] A "normalized configuration" is a positioning of a model, in space, following a predetermined orientation, with a predetermined scale. To compare the shape of two models representing an object, for example an arch or a tooth, the two models can be arranged according to the normalized configuration. The normalization methods for arranging and sizing a model according to a normalized configuration are well known. To compare the shape of two models, one can in particular use an iterative closest point search algorithm (ICP, or "Iterative Closest Point" in English, described in htps: / / fr.wikipedia.org / wiki / Iterative_Closest_Point).

[0136] "Slicing" an arch model into "tooth models" is an operation that allows the representations of teeth (tooth models) in the arch model to be delimited and made autonomous. There are computer tools for manipulating the tooth models of an arch model. An example of software for manipulating tooth models and creating a treatment scenario is the Treat program, described on the page https: / / en.wikipedia.org / wiki / Clear_aligners#cite_note-invisalignsystem-l 0.

[0137] A “statistical processing” is a processing which, when applied to a set of data, makes it possible to determine characteristics specific to this set, for example a mean, a standard deviation, or a median value. Statistical processing tools are well known to those skilled in the art.

[0138] “Metaheuristic” methods are known optimization methods. In the context of the present invention, they are preferably chosen from the group formed by:

[0139] - evolutionary algorithms, preferably chosen from evolutionary strategies, genetic algorithms, differential evolution algorithms, distribution estimation algorithms, artificial immune systems, Shuffled Complex Evolution path recomposition, simulated annealing, ant colony algorithms, particle swarm optimization algorithms, taboo search, and the GRASP method;

[0140] - the kangaroo algorithm, - the Fletcher and Powell method,

[0141] - the sound effects method,

[0142] - stochastic tunneling,

[0143] - climbing hills with random restarts,

[0144] - the cross-entropy method, and

[0145] - hybrid methods between the metaheuristic methods cited above.

[0146] A "match" or "fit" between two objects is a measure of the difference, or "distance," between the two objects. A match is maximal ("best fit") when this difference is minimal.

[0147] A "neural network" or "artificial neural network" is a set of algorithms well known to those skilled in the art. To be operational, a neural network must be trained by a learning process called "deep learning", from a learning base.

[0148] A "training database" is a database of computer records suitable for training a neural network. The quality of the analysis performed by the neural network depends directly on the number of records in the training database. Typically, the training database contains more than 1,000, preferably more than 10,000 records.

[0149] The training of a neural network is adapted to the purpose pursued and does not pose any particular difficulty to the person skilled in the art. The training of a neural network consists of confronting it with a learning base containing information on first objects and second objects that the neural network must learn to "match", that is to say to connect one to the other.

[0150] Training can be done using a "paired" or "paired" learning base, consisting of "pair" records, i.e., each containing a first object for the input of the neural network, and a second corresponding object, for the output of the neural network. We also say that the input and output of the neural network are "paired". Training the neural network with all these pairs teaches it to provide, from an object similar to the first objects, a corresponding object similar to the second objects. The article "Image-to-Image Translation with Conditional Adversarial Networks" by Phillip Isola Jun-Yan Zhu, Tinghui Zhou, Alexei A. Efros, Berkeley AI Research (B AIR) Laboratory, UC Berkeley, illustrates the use of a paired learning base.

[0151] A "reference frame" serves as a basis for measuring one or more distances. A reference frame may, for example, be a three-dimensional reference frame, for example orthonormal. The three-dimensional reference frame is preferably fixed relative to the model in question. If the model represents an arch, it may, for example, have its origin at the center of the user's oral cavity. In particular, the three-dimensional reference frame is preferably independent of the position and orientation of the portable scanner.

[0152] The dimensions (length, width, height) of an arch are conventionally measured by considering that the arch is in a horizontal plane. The height direction Y is then the vertical direction. The width direction X is the transverse direction for the user, which extends from the right to the left of the user. The length direction Z is the depth direction for the user, which extends from the front to the back of the user.

[0153] The dimensions (length, width, height) of a tooth are conventionally measured by considering that the arch is in a horizontal plane. The height direction Y' is then the vertical direction. The width direction X' is the direction of the largest dimension of the tooth when observed from the front, perpendicular to the height direction. The length direction Z' is the direction perpendicular to the Y' and X' directions.

[0154] According to the international convention of the Fédération Dentaire Internationale, each tooth in a dental arch has a predetermined number. The tooth numbers defined by this convention are shown in Figure 6.

[0155] A "notable point" is a point on an arch or tooth model that can be identified, for example, the apex of the tooth or at the tip of a cusp, a point of interdental contact, that is, of a tooth with an adjacent tooth, for example, a point mesial or distal to the incisal edge of a tooth, or a point at the center of the tooth's crown, or "barycenter."

[0156] An "angulation" is an orientation of the optical axis of the portable scanner relative to the user, when acquiring the model in step a). A 3D scanner, or "scanner", is a device for obtaining a model of a tooth or a dental arch. It conventionally uses structured light and, from different images and, preferably by matching particular points on these images, manages to constitute a 3D model.

[0157] Specifically, the handheld scanner projects structured light onto the patient's teeth while acquiring said images. The scanner can project a light pattern onto the teeth. The deformation of this pattern allows for spatial interpretation of the scene.

[0158] Classically used techniques include 1-dimensional or 2-dimensional pattern projection, multi-stripe laser triangulation (MLT), digital fringes, and phase-modulated techniques.

[0159] Alternatively or in addition to structured light projection, the portable scanner projects modulated light onto the patient's teeth while acquiring said images. The projected light is then changing and the scanner's camera measures the variation of the reflected light over time in order to deduce the distance it travels. Among the techniques conventionally used, we can cite in particular the phase-modulated technique.

[0160] Image analysis allows the construction of the model.

[0161] The images can be of the same type as images acquired by conventional intraoral 3D optical scanners.

[0162] The images are representations of the observed scene, in this case the patient's teeth, but their nature is specific to the nature of the light source illuminating the scene. The images are preferably not photographs representing the scene realistically, as a person would directly observe it.

[0163] The maximum difference in shape between the model acquired with the scanner and the actual scanned object is inversely proportional to the scanner's performance. It is called the scanner's "acquisition resolution" or "accuracy." The smaller the resolution, the more realistic the model is.

[0164] A laser remote sensor is particularly well suited to the invention because it allows extraoral acquisition of an accurate model of the arch, by the patient himself, the laser light being projected directly onto the patient's teeth. A professional scanner preferably has an accuracy of less than 5 / 10 mm (i.e. the maximum difference in shape between the model acquired with the scanner and the actual object scanned, at actual scale, is less than 5 / 10 mm), preferably less than 3 / 10 mm, preferably less than 1 / 10 mm, preferably less than 1 / 50 mm, preferably less than 1 / 100 mm and / or greater than 1 / 500 mm.

[0165] A "mobile phone" or "cell phone" is a device such as an iPhone®. Such a device typically weighs less than 500 g, or less than 200 g, is equipped with a camera with a lens allowing it to take films or photos, or even a scanner allowing it to acquire three-dimensional digital models. A mobile phone is also capable of exchanging data with another device more than 500 km away from the mobile phone, and is capable of displaying on a screen the films, photos or models that it has enabled to be acquired.

[0166] A retractor, or dental retractor, is a device for retracting the lips. It has an upper and a lower rim, and / or a right and a left rim, extending around a retractor opening and intended to be inserted between the teeth and lips. In the operating position, the user's lips rest on these rims, so that the teeth are visible through the retractor opening. A retractor thus allows the teeth to be observed without being obstructed by the lips.

[0167] The teeth, however, do not rest on the retractor, so the user can, by turning their head relative to the retractor, change which teeth are visible through the retractor opening. They can also change the distance between their dental arches. In particular, a retractor does not press on the teeth so as to separate the two jaws from each other, but on the lips.

[0168] In one embodiment, a retractor is configured to elastically spread the upper and lower lips apart so as to clear the teeth visible through the retractor opening.

[0169] In one embodiment, a spacer is configured such that the distance between the top rim and the bottom rim, and / or between the right rim and the left rim is constant.

[0170] Spacers are for example described in PCT / EP2015 / 074896, US 6,923,761, or US 2004 / 0209225. The “service position” is the position in which the user acquires the model acquired in step a). When using a holder to rigidly fix the portable scanner, the holder is partially inserted into the user's mouth, as illustrated in Figures 2 and 3.

[0171] The "closed mouth" position is the occlusion position in which the patient's upper and lower dentitions are in contact. An "open mouth" position is a mouth opening position, in which the patient's upper and lower dentitions are not in contact.

[0172] The method (apart from the acquisition operation with the portable scanner) according to the invention is implemented by computer, preferably exclusively by computer.

[0173] By "computer" is meant a computer processing unit, which includes a set of several machines, having computer processing capabilities. This unit can be integrated in particular in the portable scanner, or in a mobile phone integrating the portable scanner, or be a PC type computer or a server, for example a server remote from the user, for example be the "cloud" or a computer placed at a dental care professional. The mobile phone and the computer then include means of communication to exchange between them, in particular to transmit the updated model, optionally corrected and / or simplified, and / or one or more dimensional values ​​determined according to the invention.

[0174] Conventionally, a computer comprises in particular a processor, a memory, a human-machine interface, conventionally comprising a screen, a communication module via the internet, WIFI, Bluetooth® or the telephone network. Software configured to implement a method of the invention is loaded into the computer's memory. The computer can also be connected to a printer.

[0175] “First”, “second” are used for clarity.

[0176] Also, for clarity:

[0177] - “basic” refers to a model used in the preferred simplification process;

[0178] - “reference” refers to a model used in step b) to evaluate a dimensional value or an appearance value, or at a time at which the object modeled by the reference model is expected to have the shape or appearance of that model;

[0179] - “correction” refers to a model or time used in a preferred correction process; - “updated” refers to step a), and in particular to the model resulting from step a);

[0180] - “historical” refers to one or more models acquired prior to the updated time, in particular modeling an arch or a tooth of a “historical” person different from the user;

[0181] - “optimal” refers to a model which, among a set of models, presents the closest form to the updated model.

[0182] "Vertical", "horizontal", "right", "left", "front" or "from the front", "behind", "above", "below" refer to a user standing upright, vertically.

[0183] "Comprising" or "comprising" or "presenting" should be interpreted in a non-restrictive manner, unless otherwise indicated.

[0184] Brief description of the figures

[0185] Other characteristics and advantages of the invention will become apparent upon reading the detailed description which follows and upon examining the attached drawing in which:

[0186] - [Fig 1] Figure 1 represents, schematically, an example of a kit according to the invention;

[0187] - [Fig 2] Figure 2 shows, schematically, the kit according to the invention in a service position, the user being seen from the front;

[0188] - [Fig 3] Figure 3 shows, schematically, the kit according to the invention in a service position, the user being seen from the side;

[0189] - [Fig 4] Figure 4 represents an acquired model, with three different acquisition resolutions;

[0190] - [Fig 5] Figure 5 is an example of an acquired model, after processing to cut tooth models; an example of a tooth model is colored in dark gray;

[0191] - [Fig 6] Figure 6 illustrates the tooth numbering used in the dental field;

[0192] - [Fig 7] Figure 7 illustrates an acquisition method according to the invention;

[0193] - [Fig 8] Figure 8 illustrates a first correction method according to the invention;

[0194] - [Fig 9] Figure 9 illustrates a second correction method according to the invention;

[0195] - [Fig 10] Figure 10 schematically represents an example of a portable scanner in one embodiment of the invention;

[0196] - [Fig 11] Figure 11 shows different images providing additional data; - [Fig 12] Figure 12 schematically represents an example of a device for implementing an image acquisition method according to the invention.

[0197] In the various figures, like references are used to designate analogous or identical objects.

[0198] Detailed description

[0199] The objective of a method according to the invention, illustrated in Figure 7, is to quickly provide a digital three-dimensional model of a user's arch, or part of this arch, i.e. an "updated model".

[0200] In step a), at an updated time, the user generates, with a portable scanner 6, the “acquired model”.

[0201] Preferably, the acquired model represents at least 2, preferably at least 3, preferably at least 4 teeth, preferably all the teeth of the arch.

[0202] A portable scanner is a self-contained scanner, particularly in that it has its own power source, typically a battery, and in that its weight allows it to be handled by hand.

[0203] Preferably, the portable scanner weighs less than 1 kg, preferably less than 500 g, preferably less than 200 g, and / or more than 50 g.

[0204] Preferably, the largest dimension of the portable scanner is less than 30 cm, 20 cm or 15 cm and / or greater than 5 cm.

[0205] The portable scanner preferably has an acquisition resolution of less than 10 mm, preferably less than 5 mm, preferably less than 3 mm, preferably less than 2 mm, preferably less than 1 mm, preferably less than 1 / 2 mm, preferably less than 1 / 5 mm, preferably less than 1 / 10 mm.

[0206] The portable scanner is preferably configured so that the acquired pattern has more than 5,000 and / or less than 200,000, or less than 150,000 points.

[0207] Figure 4 shows examples of arcade 8 models acquired with a handheld scanner with 5000, 11,500, and 154,000 points, respectively.

[0208] The portable scanner 6 can be integrated into a mobile phone 12, as in FIG. 1, or be in communication with a mobile phone. Step a) is thus easy for the user to implement. The mobile phone also makes it possible to transfer the updated model to a remote computer.

[0209] The updated time may be during orthodontic treatment undergone by the user or outside of any orthodontic treatment.

[0210] In step a), the portable scanner is preferably carried by hand by the user. Preferably, it is not immobilized, for example by means of a structure resting on the ground, for example a tripod. Preferably, the user's head is not immobilized.

[0211] In one embodiment, the user scans the dental arch without using any device other than the handheld scanner.

[0212] In a preferred embodiment, he uses a tool to free his lips, and better expose the dental arch to the portable scanner. The tool can be, for example, a spoon inserted into his mouth.

[0213] In one embodiment, he uses a retractor and / or a mouth support which he partially inserts into his mouth.

[0214] In a particularly advantageous embodiment, in step a), the user uses a kit 10 comprising the portable scanner 6 and a support 14 (figure 1) allowing simultaneously

[0215] - to spread the user's lips to expose the teeth, and

[0216] - to facilitate the positioning and orientation of the portable scanner 6 in relation to the teeth.

[0217] The support 14 preferably has the general shape of a tubular body, one opening of which, called the “oral opening” Oo, is intended to be introduced into the patient's mouth, and the opposite opening of which, called the “acquisition opening”, faces the objective of the portable scanner, rigidly fixed, preferably removably, on the support 14.

[0218] Preferably, the acquisition aperture also faces a flash of the portable scanner, which allows it to be used to illuminate the user's teeth during acquisition.

[0219] The support 14 makes it possible to define a spacing between the portable scanner and the oral opening Oo as well as an orientation of the portable scanner relative to the oral opening. Advantageously, in the service position, the data acquired by the portable scanner 6 through its objective, the acquisition opening and the oral opening are thus acquired at a predetermined distance from the user's teeth and according to a predefined orientation. Preferably, the support is configured so that this spacing and this orientation are constant.

[0220] Preferably, the support 14 comprises:

[0221] - a tubular spacer 16 which defines the oral opening Oo and preferably comprises a rim 22 extending radially outwards, at the periphery of the oral opening Oo, intended to be introduced between the lips and the teeth of the user, and

[0222] - an adapter 18 on which the portable scanner 6 is fixed, for example clamped between two jaws 241 and 242, as illustrated in figure 1, the adapter 18 being rigidly fixed on the spacer 16, preferably in a removable manner, for example by means of a clip 20, or made in one piece with the spacer, so that the lens of the portable scanner can “see” the oral opening.

[0223] The maximum height I122 of the rim 22 is preferably greater than 3 mm and less than 10 mm.

[0224] To acquire the acquired model, the user assembles the tubular spacer 16 to the adapter 18 by means of the clips 20, then the portable scanner on the adapter 18 so that the portable scanner can then perform a scan through the tubular spacer 16 and the adapter 18. He then introduces into his mouth the end of the tubular spacer opposite the portable scanner, inserting the rim 22 between his lips and the teeth. The lips thus rest on the tubular spacer 16, outside the latter, which allows a clear view of the teeth through the oral opening Oo.

[0225] In the service position obtained, as illustrated in Figures 2 and 3, the teeth do not rest on the support, so that the user U can, by turning his head relative to the support, modify the teeth that are visible to the portable scanner through the oral opening. He can also modify the spacing between his dental arches. In particular, the support separates the lips, but does not press on the teeth so as to separate the two jaws from each other.

[0226] The acquired model can represent totally or partially one dental arch or both dental arches. In one embodiment, the model of the arch acquired with the portable scanner is cut, preferably to define at least one tooth model 30. In one embodiment, the updated model is thus reduced to a portion of the acquired model, preferably reduced to a tooth model.

[0227] Preferably, steps b) and c) are then carried out successively for each tooth model.

[0228] Cutting a model can use any known cutting process.

[0229] Correcting the updated model, possibly resulting from a cutting of the acquired model, consists of modifying it so that it is more consistent with the object it models. To this end, we can notably improve the resolution of the model and / or complete it and / or give it more realistic colors, for example to make it hyper realistic, and / or clean it. Cleaning the model consists of removing parts of the model that do not model the target object, for example removing the representation of an orthodontic bracket when the target object is a tooth or removing defects resulting from the acquisition operation, in particular to clean artifacts due to saliva during acquisition.

[0230] Correction

[0231] The updated model is preferably processed by computer for correction. Correction of the updated model can be carried out after or before a simplification.

[0232] In a preferred embodiment, illustrated in Figure 8, the updated model is compared to a "correction model" and then corrected based on the results of this comparison.

[0233] Preferably, the following steps are carried out when the model to be corrected is a tooth model: i) creating a historical library comprising more than 1,000 tooth models, called “historical tooth models”, and assigning a tooth number to each historical tooth model; ii) analyzing the tooth model to be corrected, so as to determine the number of the tooth modeled by said tooth model to be corrected; iii) searching, in the historical library, for a historical tooth model having the same number and exhibiting maximum proximity to said tooth model to be corrected, or “optimal tooth model”; iv) modifying the tooth model to be corrected based on information relating to the optimal tooth model, the modification possibly comprising a replacement of the tooth model to be corrected by the optimal tooth model.

[0234] In step i), a historical library is created, preferably comprising more than 2,000, preferably more than 5,000, preferably more than 10,000 and / or less than 1,000,0000 historical tooth models.

[0235] A historical tooth model can be obtained in particular from a model of a dental arch of a "historical" patient obtained with a scanner. This arch model can be cut in order to isolate the representations of the teeth, that is to say the tooth models, as in Figure 5.

[0236] The historical library therefore contains historical tooth models and the numbers of the teeth modeled by these historical tooth models.

[0237] In step ii), the tooth model to be corrected is analyzed to determine its number.

[0238] Tooth numbers are conventionally assigned according to a standard rule. Therefore, it is sufficient to know this rule and the number of a modeled tooth to determine the numbers of the other tooth models.

[0239] In a preferred embodiment, the shape of the tooth model to be corrected is analyzed to define its number. This shape recognition is preferably carried out using a neural network.

[0240] Preferably, a neural network is used, preferably chosen from “Object Detection Networks”, for example from the following neural networks: 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, 2014, OverFeat (Sermanet et al.), 2013, GoogleNet (Szegedy et al.), 2015, VGGNet (Simonyan and Zisserman), 2014, R-CNN (Girshick et al.), 2014, Fast R-CNN (Girshick et al.), 2015, ResNet (He et al.), 2016, Faster R-CNN (Ren et al.), 2017 ... al.), 2016, FPN (Lin et al.), 2016, YOLO (Redmon et al.), 2016, SSD (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, YOL09000 (Redmon and Farhadi), 2017, Hourglass (Newell et al.), 2016, 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.), 2018, NASNet (Zoph et al.), 2019, CornerNet (Law and Deng), 2018, FSAF (Zhu et al.), 2019, SENet (Hu et al.), 2018, ExtremeNet (Zhou et al.), 2019, NAS-FPN (Ghiasi et al.), 2019, Detnas (Chen et al.), 2019, FCOS (Tian et al.), 2019, CenterNet (Duan et al.), 2019, EfficientNet (Tan and Le), 2019, AlexNet (Krizhevsky et al.), 2012, Cbnet (2020), Pointgnn (2020), MDFN (2020), CADN (2021).

[0241] Preferably, the neural network is trained by providing it with tooth models as input and the associated tooth number as output. The neural network thus learns to provide a tooth number for a tooth model presented to it as input.

[0242] The tooth model to be corrected can then be modified from a historical tooth model with the same number.

[0243] In step iii), the historical library is searched for the historical tooth model with the maximum proximity to the tooth model to be corrected, among the historical tooth models having the same number as the tooth model to be corrected. This historical tooth model is called the "optimal tooth model".

[0244] "Proximity" is a measure of the difference in shape between the historical tooth model and the tooth model to be corrected. The difference in shape can be, for example, an average distance between the historical tooth model and the tooth model to be corrected after they have been arranged in a standardized configuration.

[0245] Preferably, maximum proximity, or "maximum concordance," is considered to be achieved when the cumulative Euclidean distance between the points of the historical tooth model and those of the tooth model to be corrected is minimal.

[0246] In step iv), the tooth model to be corrected is modified based on information relating to the optimal tooth model, which serves as the correction model.

[0247] For example, areas of the tooth model to be corrected which, in the standardized configuration, are deviated from the optimal tooth model by a distance greater than a first distance threshold, for example by more than 1 mm, may be replaced by areas of the optimal tooth model which face them, and / or "white" areas of the tooth model to be corrected, i.e. undefined areas, which face areas of the optimal tooth model which are not white may be replaced by these areas of the optimal tooth model. The modification of the tooth model to be corrected may also consist of replacing the tooth model to be corrected with the optimal tooth model.

[0248] Preferably, steps i) to iv) are performed for each tooth model cut from the acquired model.

[0249] The above method can be applied to an updated model representing a dental arch. In steps ii) and iii), the classification criterion of the updated model is adapted accordingly. Instead of being the tooth number, the classification criterion can be, for example, one or more attributes relating to one arch, for example the width of the arch, or to both arches. The classification criterion can in particular be chosen from those listed above, in the definition of a classification criterion.

[0250] The updated model can be submitted to a neural network trained for this purpose using a learning base.Le réseau de neurones peut être en particulier choisi parmi les réseaux suivants : Shape Inpainting using 3D Generative Adversarial Network and Recurrent Convolutional Networks (2017), Deformable Shape Completion with Graph Convolutional Autoencoders (2018), Learning 3D Shape Completion Under Weak Supervision (2018), PCN: Point Completion Network (2019), TopNet: Structural Point Cloud Decoder (2019), RL-GAN-Net: A Reinforcement Learning Agent Controlled GAN Network for Real-Time Point Cloud Shape Completion (2019), Cascaded Refinement Network for Point Cloud Completion (2020), PF-Net: Point Fractal Network for 3D Point Cloud Completion (2020), Point Cloud Completion by Skip-attention Network with Hierarchical Folding (2020), GRNet: Gridding Residual Network for Dense Point Cloud Completion (2020), et Style-based Point Generator with Adversarial Rendering for Point Cloud Completion (2021).

[0251] For example, each record in the learning base may include:

[0252] - an incomplete model of an object, for example a dental arch, or a tooth model, and

[0253] - the same model, but complete.

[0254] Preferably, the objects modeled in the recordings belong to the same class defined by means of a classification criterion. For example, if these objects are teeth, the tooth number of the tooth models is preferably identical for all the recordings in the training base. Preferably, a neural network specialized in image generation is used, for example:

[0255] - Cycle-Consistent Adversarial Networks (2017),

[0256] - Augmented CycleGAN (2018),

[0257] - Deep Photo Style Transfer (2017),

[0258] - FastPhotoStyle (2018),

[0259] - pix2pix (2017),

[0260] - Style-Based Generator Architecture for GANs (2018),

[0261] - SRGAN (2018),

[0262] - WaveGAN 2020

[0263] - GAN-LSTM 2019,

[0264] - CSGAN 2021,

[0265] - DivCo 2021.

[0266] After being trained with this learning base, by providing it, successively for each recording, the incomplete model and as output the corresponding complete model, the neural network can transform an incomplete model into a complete model.

[0267] The complete model serves as a “correction model”.

[0268] The correction model can be used to perform quality control during the acquisition of the acquired model, i.e. to check that this acquisition has not generated defects. A defect is a part of the acquired model that does not correctly represent the dental arch(s). For example, the model may have roughness or indentations that, in reality, i.e. on the dental arch(s), do not exist.

[0269] Correction of the acquired model can also be used to remove such defects resulting from the acquisition operation.

[0270] Cleaning

[0271] A cleaning of the updated model is preferably carried out, independently of the modification method above (steps i) to iv)). The objective is to process the updated model to remove the representation of an external object, but also to replace it with a surface representing as faithfully as possible the surface of the arch covered by this object. In a preferred embodiment, illustrated in Figure 9, the updated model is cleaned to remove the representation of an object external to the user, for example an orthodontic bracket, partially masking at least the object to be modeled, for example a tooth, by proceeding according to the following steps: i') definition of:

[0272] - a first certain zone made up of the points of the updated model representing the object to be modeled, for example a tooth, with a precision greater than 90%, or “first certain points”, and

[0273] - a first uncertain zone, constituting the 100% complement of the updated model; ii) extrapolation of the first certain zone, from the first certain zone alone, to define, in the region of the first uncertain zone, a first reconstituted zone, then definition of:

[0274] - a second certain zone made up of points of the first uncertain zone separated from the first reconstituted zone by a distance less than a threshold distance, or

[0275] "second certain points"; and

[0276] - a second uncertain zone, constituting the 100% complement of the first uncertain zone; iii') extrapolation of the set consisting of the first and second certain zones, from the set alone, to define, in the region of the second uncertain zone, a second reconstituted zone, then replacement of the second uncertain zone by the second reconstituted zone, so as to obtain a cleaned updated model.

[0277] These operations advantageously make it possible to remove the representation of the external object from the updated model and to obtain a cleaned updated model representing the object to be modeled with good precision.

[0278] The external object may include all or part of an orthodontic appliance, a crown, an implant, a bridge, an elastic band or a veneer. It may also be food, a drop of saliva, or all or part of a tool.

[0279] In step i'), the representation of the external object is isolated. More precisely, the points of the updated model which are, with almost certainty, representations of points of the arcade are identified. Algorithms for detecting objects in images are well known to those skilled in the art. Preferably, a neural network is used, preferably chosen from “Object Detection Networks”, for example from those listed above.

[0280] These neural networks are capable, after training, of detecting points in the updated model which, with an accuracy greater than a precision threshold of 90% or more, represent points in the arcade, or "first certain points". The set of these points, called the "first certain zone", constitutes a fraction of the updated model. The points in the updated model which are not in the first certain zone together form the "first uncertain zone".

[0281] Preferably, the accuracy threshold is greater than 95%, preferably greater than 98%, preferably greater than 99% and / or less than 99.99%.

[0282] Training a neural network to detect an object in an image poses no difficulty for those skilled in the art. For example, it can be provided with arch models as input and the same arch models as output, on which the areas representing the arch and the areas representing an external object have been identified. It thus learns to define these areas on an arch model.

[0283] The following steps aim to fill the "first white area" of the updated model that appears if we remove the first uncertain area.

[0284] In step ii'), the first certain zone is used to define a surface to fill the said first white zone. This surface is called the "first reconstituted zone".

[0285] The techniques for performing this extrapolation are well known. Examples include WENDLAND, Holger. Piecewise polynomial, positive definite and compactly supported radial functions of minimal degree. Advances in computational Mathematics, 1995, vol. 4, no. 1, pp. 389-396.

[0286] To refine the reconstruction of the surface of the arcade masked by the external object, we then identify the points of the first uncertain zone which are close to the first reconstructed zone. These points are therefore points of the updated model which are close to a surface extrapolated from points representing, with near certainty, points of the arcade.

[0287] These points of the updated model, or "second certain points", are also considered, with great precision, points representing points of the arcade. We call the set of these points "second certain zone". These points are therefore points of the updated model that the analysis of step i') had discarded, but which are retained because they are close to a surface extrapolated from the points that the analysis of step i') had retained.

[0288] The points of the updated model that do not belong to the first certain zone, nor to the second certain zone together form the “second uncertain zone”.

[0289] The proximity of a point in the first uncertain zone to the first reconstructed zone can be assessed by measuring the Euclidean distance between this point and this first reconstructed zone. A point in the first uncertain zone is considered to fall within the second certain zone if this distance is less than a threshold distance.

[0290] If the model is at scale 1, i.e. represents the modeled object with the real dimensions of this object, the threshold distance is preferably greater than 0.1 mm and / or less than 1 mm.

[0291] The threshold distance can also be determined by an analysis of the distribution of said Euclidean distances between the points of the first uncertain zone and the first reconstructed zone, for example as a function of the mean and the standard deviation of these distances. A dynamic calculation with a method of the “3 sigma rule” type can be implemented, for example.

[0292] In step iii'), the objective is to replace the second uncertain zone with a second reconstructed zone that better matches the surface of the arch. To this end, the first and second certain zones are extrapolated into the region of the second uncertain zone.

[0293] Particularly noteworthy, the extrapolation is not based on the first certain zone alone, but on the entire set of the first and second certain zones. Tests have shown that this extrapolation thus makes it possible to obtain a second reconstructed zone representing, with high reliability, the surface of the arch.

[0294] The extrapolation in step iii') may use the same methods as those implemented in step ii'). It may also use different methods.

[0295] The first and second certain zones and the second reconstructed zone constitute the cleaned updated model, on which the representation of external objects has been removed. Preferably, the updated model is made hyper-realistic, preferably using a neural network.

[0296] The updated model can be submitted to a neural network trained for this purpose using a learning base, as described for example in http: / / cs230.stanford.edu / projects_winter_2020 / reports / 32639841.pdf.

[0297] For example, each record in the learning base may include:

[0298] - a rough model of an object, for example a dental arch, or a tooth model, and

[0299] - the same model, but hyperrealistic.

[0300] The raw models preferably have a similar appearance to the updated model. They may be scans, preferably made with a scanner identical or similar to the portable scanner used in step a).

[0301] Raw models may, for example, have been made hyper-realistic by projecting photos.

[0302] Preferably, the objects modeled in the records belong to the same class defined by means of a classification criterion. For example, if these objects are teeth, the tooth number of the tooth models is preferably identical for all records in the training base.

[0303] Preferably, a neural network specialized in image generation is used, for example:

[0304] - Cycle-Consistent Adversarial Networks (2017)

[0305] - Augmented CycleGAN (2018)

[0306] - Deep Photo Style Transfer (2017)

[0307] - FastPhotoStyle (2018)

[0308] - pix2pix (2017)

[0309] - Style-Based Generator Architecture for GANs (2018)

[0310] - SRGAN (2018).

[0311] After being trained with the learning base, by successively providing it for each recording with the raw model as input and the hyperrealistic model as output, the neural network can transform a raw model into a hyperrealistic model. Thanks to the correction methods described above, an updated model can be advantageously transformed into an updated model representing the modeled object, for example the real arch, with great realism.

[0312] Simplification

[0313] Before being used, for example in step b), the updated model, possibly corrected, can be simplified, in particular to facilitate processing in step b). The simplification can also be carried out before or after the possible correction, or between two correction treatments.

[0314] The updated, preferably corrected, model is preferably displayed on a screen, preferably on the screen of the mobile phone when the latter integrates the portable scanner and / or on a screen in the office of a dental care professional.

[0315] One or more of the cutting and / or correction and / or cleaning and / or appearance correction and / or simplification operations described above may be implemented

[0316] - in the portable scanner, preferably in the mobile phone incorporating the portable scanner or in communication with an acquisition tool, or

[0317] - in a computer processing center in communication with said mobile phone, to which said mobile phone has transmitted the acquired model or the updated model.

[0318] In step b), at least one value of a dimensional parameter of the updated model, or “dimensional value”, and / or at least one value of an aspect parameter of the updated model, or “aspect value”, is determined.

[0319] Step b) can be implemented in the mobile phone or in a processing center, remote from the mobile phone and to which the mobile phone transmits the updated model.

[0320] The updated model used in step b) can be

[0321] - the acquired model, i.e. the raw model as generated by the portable scanner, or

[0322] - a part of the acquired model, for example resulting from a computer cutting of the acquired model, or

[0323] - the said model acquired after correction and / or simplification, or

[0324] - the said part of the acquired model after correction and / or simplification. A “dimensional value” is a value which depends on the shape of the updated model. This value is that of a “dimensional parameter”, which can be chosen in particular from

[0325] - a dimension of the updated model, for example the width, length or height of the dental arch or a tooth;

[0326] - a distance of a point of the updated model from a reference frame, or

[0327] - a parameter derived from these dimensions and distances, for example an orthodontic index, a canine / molar occlusion class, a measurement of a vertical overjet (in English

[0328] "overbite") or a horizontal overjet, a tooth number, or an indication of the presence or absence of a tooth.

[0329] The dimensional value can be measured on the updated model or obtained from one or more measurements made on the updated model.

[0330] For example, one can measure a gap between two teeth, the position of a remarkable point in relation to a reference point, for example orthonormal, fixed in relation to the updated object (arch or tooth in particular) or in relation to another tooth, for example to evaluate the alignment of a tooth in relation to the other teeth, the misalignment of a tooth in relation to the others or in relation to a predetermined position in the reference point, the positioning of one or more teeth in relation to a fixed or removable orthodontic appliance positioned on the teeth or soft tissues, the index of crowding and / or irregularity of the arch, the misalignment of a tooth in relation to the other teeth or in relation to the gum, a deformation of a tooth, for example the depth of a cavity, a deformation of the gum, the width of the arch or the relative position of one arch in relation to the other.

[0331] The dimensional value can also be a measure of a difference in shape between the updated model and a reference model. In particular, one can compare the shapes and / or positions of teeth in the updated model and in a reference model.

[0332] An "appearance value" is a value that depends on the appearance of the surface of the updated model. This value is that of an "appearance parameter", which can be chosen in particular from a color, a reflectance, a transparency, a reflectivity, a tint, a translucency, an opalescence, an index on the presence of tartar, dental plaque or food on the tooth. The appearance value can also be a measure of a difference in appearance between the updated model and a reference model. In particular, the appearances of teeth in the updated model and in a reference model can be compared.

[0333] The reference model is chosen based on the intended application.

[0334] For example, if the objective is to check whether the dental situation is normal at the updated time, that is to say to check that it does not require intervention by a dental care professional, in particular for therapeutic or aesthetic reasons, the reference model may be a model that represents an object of the same type as the updated object, or even the updated object, in a dental situation considered normal at the updated time.

[0335] The reference model may be representative of a set of individuals, preferably comprising more than 100 individuals, preferably more than 1000 individuals and / or less than 1,000,0000 individuals, for example

[0336] - a tooth from a typodont if the updated object is a tooth, or

[0337] - an arcade corresponding to an average arcade shape for all individuals if the updated object is an arcade.

[0338] The reference model may be a model that represents an object of the same type as the updated object, preferably the updated object, but in a position and / or with a shape and / or with an appearance that is that(s) of the anticipated updated object(s) for a reference instant, prior or subsequent to the updated instant or simultaneous with the updated instant.

[0339] The reference time may in particular be a stage of an orthodontic treatment undergone by the user (for example at the start or end of the orthodontic treatment or at an intermediate stage of the orthodontic treatment, in English “intermediate set-up”, or “staging”).

[0340] The time interval between the updated and reference times may be greater than one week, preferably greater than 2 weeks, 4 weeks, 6 weeks, 2 months and / or less than 6 months.

[0341] The reference model may be obtained by means of a scanner, for example with the user's portable scanner, preferably by means of a professional scanner, or be obtained by construction from photos of the arch and a library of historical teeth, as described in EP18184486, equivalent to US16 / 031,172. The reference model is preferably obtained by computer simulation, so that it represents the dental arch in the configuration intended at the reference time, in particular at the end of an orthodontic treatment or at the updated time.

[0342] For example, it may result from a modification of an initial model, for example generated by means of a scan of a user's arch, preferably generated more than a week before the updated time, for example at the start of an orthodontic treatment. The initial model is conventionally cut in order to define tooth models. The movement of the tooth models then makes it possible to simulate the progress of the orthodontic treatment.

[0343] An example of software for manipulating tooth models and creating a treatment scenario is the Treat program, described at https: / / en.wikipedia.org / wiki / Clear_aligners#cite_note-invisalignsystem-10. US5975893A also describes the creation of a treatment scenario.

[0344] In one embodiment, the following steps are carried out:

[0345] - a cutting of the reference model produced previously at the updated time or of the updated model, so as to generate tooth models,

[0346] - a displacement of one or more said tooth models, without deformation of the tooth models, until a modified model having a maximum shape concordance with the updated or reference model is obtained, respectively,

[0347] - an evaluation of the positioning difference (determination of at least one dimensional value) of at least one tooth model between its position in the reference or updated model, respectively, and its position in the modified model.

[0348] In step c), the dimensional value and / or the appearance value determined in step b) is / are used, in particular to decide whether an action for therapeutic or aesthetic purposes is necessary and / or to contribute to the determination of this action.

[0349] The dimensional value and / or the appearance value, and preferably the updated model, may be presented to the user, for example by being displayed on the screen of his mobile phone.

[0350] Additionally or alternatively, they may also be transmitted, preferably by radio, preferably by a mobile phone incorporating the portable scanner or in communication with the acquisition tool, to a dental care professional, in particular an orthodontist or to a remote computer in communication with the mobile phone. Preferably, the dimensional value and / or the appearance value is / are interpreted, preferably by computer, preferably by a mobile phone incorporating the portable scanner, and a recommendation is presented to the user, preferably on the screen of his mobile phone.

[0351] Using updated images

[0352] In a particularly advantageous embodiment, in step a), the user acquires, in addition to the updated model, one or more “updated” images, preferably extra-oral. Preferably, he uses the mobile phone implemented to acquire the acquired model.

[0353] Preferably, the updated images are photographs or images extracted from a film. They are preferably in color, preferably in real color. Preferably, they represent the dental arches substantially as seen by the operator of the device acquiring these images.

[0354] The information provided by the updated images makes it possible to supplement that provided by the acquired model. The information may in particular relate to a dimension and / or the appearance of one or more objects, preferably teeth, represented on the updated image(s). In particular, the analysis of an updated image, preferably by computer, makes it possible to confirm and / or correct a dimensional value and / or an appearance value determined from the updated model, and / or to supplement the information drawn from the updated model.

[0355] For example, the updated model may detect a cavity on the surface of a tooth, and an updated image may reveal a darker area at the cavity location. The updated image thus confirms the presence of the cavity. It also confirms its position. Analyzing the model and updated images thus makes it possible to detect and track the progression of cavities.

[0356] Updated images can also provide very reliable information about the appearance of teeth, such as their color. Projected onto the updated model, they allow the surface of the updated model to be colored very realistically.

[0357] More preferably, several updated images are acquired taken at different angles, i.e. with different orientations of the acquisition device relative to the user's oral cavity. For example, the set of updated images may comprise 6 images representing the dental arches "front views", "right-front views", "right views", "left-front views", "left views" and "bottom views", respectively.

[0358] Preferably, at least one updated image is acquired facing the user (front view). Preferably, at least one updated image is acquired from the right of the user, and at least one updated image is acquired from the left of the user.

[0359] The set of updated images preferably comprises more than two, preferably more than three, preferably more than 5, preferably more than 6 and / or less than 30, preferably less than 20, preferably less than 15, preferably less than 10 updated images.

[0360] In one embodiment, the updated images are processed to generate a said correction model and / or a said reference model. For this purpose, all conventional techniques can be implemented.

[0361] The acquisition of two models at the updated time, namely the updated model and a model obtained from updated images, and then the comparison of these models advantageously makes it possible to make the best use of the 3D and 2D representations provided by the portable scanner and the image acquisition device, respectively.

[0362] The procedure can be implemented independently of any orthodontic treatment, in particular to monitor that the position and / or shape of the teeth are not "abnormal", i.e. when they do not meet a therapeutic or aesthetic standard. Preferably, an appointment with a dental professional should then be made. The procedure can be implemented before orthodontic treatment.

[0363] Prior to orthodontic treatment, the process can be implemented in particular to acquire the positioning and anatomy of the teeth of the future patient and to launch the manufacture of an interceptive orthodontic appliance or a custom-made orthodontic appliance, for example transparent orthodontic aligners, or to design an individualized treatment using archwires and brackets.

[0364] The method can be implemented during an orthodontic treatment, in particular to monitor its progress, step a) being implemented less than 3 months, less than 2 months, less than 1 month, less than 1 week, less than 2 days after the start of the treatment, i.e. after the fitting of an appliance intended to correct the positioning of the user's teeth, called an "active retention appliance". During an orthodontic treatment, the method can be implemented to acquire an updated model of the teeth and allow the manufacture of a new orthodontic appliance, for example an implant, an orthodontic splint, or a vestibular orthodontic appliance.

[0365] Preferably, the updated model generated in step a) and / or the value(s) determined in step b) is / are transmitted to a dental professional to assist in making a diagnosis.

[0366] The method can also be implemented after orthodontic treatment, to check that the positioning of the teeth does not change unfavorably ("relapse"). Step a) is then preferably implemented less than 3 months, less than 2 months, less than 1 month, less than 1 week, less than 2 days after the end of the treatment, that is to say after the installation of a device intended to keep the teeth in position, called a "passive retention device".

[0367] The dimensional value is preferably used for

[0368] - detect a recurrence, and / or

[0369] - determine the speed of change in the positioning of the teeth, and / or

[0370] - optimize the date of making an appointment with a dental care professional, and / or

[0371] - evaluate the effectiveness of orthodontic treatment, and / or

[0372] - assess the evolution of the positioning of teeth towards a reference model corresponding to a determined positioning of the teeth, in particular an improved positioning of the teeth, and / or

[0373] - modify an ongoing orthodontic treatment, for example by manufacturing a new series of orthodontic aligners, and / or

[0374] - in dentistry, and / or

[0375] - visualize and / or measure and / or detect dental plaque, and / or caries, and / or micro-cracks, and / or wear, for example resulting from bruxism or the use of an active or passive orthodontic appliance, in particular in the event of breakage or detachment of an orthodontic arch;

[0376] - visualize and / or measure and / or detect a change in volume, in particular during tooth growth or following an intervention by a dental care professional, for example a deposit of glue on the surface of the teeth; - assess the opportunity for interceptive treatment, before any orthodontic treatment, in particular to assess the benefit of orthodontic treatment.

[0377] The appearance value is preferably used to detect or evaluate a position or shape of a stain or decay.

[0378] In a particularly advantageous embodiment, both the dimensional value and the appearance value are used. Advantageously, the method can thus be used for precise and localized monitoring of the development of certain pathologies, in particular stains, demineralization, or cavities.

[0379] As is now clear, the invention provides a method enabling a particular user, for example a patient, to generate a model of one or more of his arches, or one or more of his teeth. He does not need any specific hardware, other than the portable scanner, which is preferably integrated into his mobile phone.

[0380] The acquired model can be acquired without introducing the portable scanner into the user's mouth, i.e. extraorally. Processing the updated model to correct it allows in particular to correct it to model regions of the mouth to which the portable scanner has not had access, for example in an interproximal space.

[0381] In one embodiment, in step a), the acquired model is coarse. It may in particular represent a “3D skeleton” of the user’s dental arch(s), and comprise only less than 500 points, less than 200 points, less than 100 points or less than 50 points and / or more than 10 points. Processing the updated model to correct it, in particular with a neural network or from a historical library, advantageously makes it possible to reconstruct a much more precise model of the user’s dental arch(s).

[0382] In one embodiment, the portable scanner is partially inserted into the user's mouth. Advantageously, the intrados of the teeth can be scanned.

[0383] As shown in Figure 10, preferably, the portable scanner 6 comprises a mobile phone 12 and an acquisition tool 31 in communication with the mobile phone, preferably by radio, preferably by Bluetooth®. Communication by cable is also possible.

[0384] The acquisition tool is provided with an acquisition head 32 which can be introduced into the user's mouth. The acquisition head acquires the acquired model and transmits it to the mobile phone 12, or acquires a signal, for example a set of images, and transfers it to the mobile phone 12 so that the latter generates the acquired model from said signal.

[0385] Preferably, the acquisition tool does not have a physical link to the mobile phone or is connected to the mobile phone by a flexible link, for example a cable.

[0386] Preferably, the acquisition tool has a handle 34 facilitating its handling, by the user himself or one of his relatives, for example in the manner of a toothbrush.

[0387] In one embodiment, the acquisition tool is attached to the mobile phone, for example by means of a clip, a hook-and-loop strip, clamping jaws, a screw, a magnet, a cover or a flexible, preferably elastic, strip. The attachment may also result from a form fit with the mobile phone. For example, the acquisition tool may be attached to a phone case.

[0388] In one embodiment, the method also implements a measuring head in communication with the mobile phone and which is introduced into the user's mouth in order to acquire additional data, for example data on the interdental space of the teeth the lingual surfaces of the teeth the palate including for example the midpalatal suture the soft tissues (canker sores, benign or malignant lesions, recessions, etc.) the color of the teeth the presence of cavities or stains the condition and / or shape of implants, crowns and / or bridges the condition of vestibular or lingual treatment devices (e.g. lingual or vestibular brackets, maxillary expander or any other treatment aid) or retention (palatal arch) the distances between the different parts of the same vestibular device,lingual or any other auxiliary condition of anchoring devices (mini-screw type) distance between anchoring devices and appliances present in the mouth soft tissue stitches post-surgical soft tissue healing Spee curve Wilson curve intercanine distance intermolar distance,

[0389] Figure 11 shows different images providing additional data, in particular on the palate including a mid-palatal suture (image 1), soft tissue sutures (image 2), distances between the different parts of the same vestibular, lingual or any other auxiliary device (images 3 and 4), the condition and / or shape of implants, crowns and / or bridges (images 5 and 8), the condition of anchoring devices (miniscrew type) and the distance between the anchoring devices and the devices present in the mouth (image 6), the condition of vestibular or lingual treatment devices (for example lingual brackets, vestibular, maxillary expander or any other treatment auxiliary) or retention (palatal arch) (image 7), the interdental space and post-surgical soft tissue healing (image 9), the lingual surfaces of the teeth (image 10), the intercanine distance and the intermolar distance (image 10), the shade of the teeth (image 11),the curve of Spee (image 12), the Wilson curve (image 13), and the presence of cavities or stains (image 14).

[0390] The measuring head may be integrated into a measuring tool having one or more of the characteristics of the acquisition tool. Unlike the latter, however, the measuring tool is not used for acquiring the acquired model.

[0391] The acquired model can then be corrected, in particular to be completed and / or cleaned and / or made hyperrealistic. The user can transmit to a dental professional, possibly to a dental professional he has never met, a model that the dental professional can analyze, in particular to establish a diagnosis and / or to give advice to the user and / or to set an appointment date.

[0392] Of course, the invention is not limited to the embodiments described and shown.

[0393] The methods of correcting and simplifying the updated model described above are inventions, independently of the method of description.

[0394] Improvements

[0395] Beyond the method described above and more generally, the invention also relates to a method for acquiring at least one image of at least one dental arch of a user by means of a mobile telephone and an acquisition tool comprising an acquisition head provided with a camera, preferably capable of being introduced into the user's mouth, method in which the acquisition head:

[0396] - acquires said image and transmits it to the mobile phone, or

[0397] - acquires a signal and transfers it to the mobile phone so that said mobile phone generates the image from said signal, independently or with the help of a computer with which said mobile phone is in communication.

[0398] Said at least one image is preferably a photograph, preferably a photograph representing the dental arch in a realistic manner, as a person would directly observe it.

[0399] The image can be used to generate a model as in step a), but the image acquisition method according to the invention is no longer limited to this particular embodiment, the image being able to be used for other purposes. This method is therefore referred to below as a “generalized method”.

[0400] To the extent that a feature described above for step a) is technically compatible with the generalized method, it can however be applied to this method.

[0401] The mobile phone and the acquisition tool are preferably operated exclusively by the user.

[0402] The acquisition can be performed extraorally, with the camera of the acquisition tool not entering the user's mouth. The acquisition can be performed intraorally, with the camera of the acquisition tool entering the user's mouth.

[0403] In one embodiment, the acquisition tool is attached to the mobile phone, for example by means of a clip, a hook-and-loop strip, clamping jaws, a screw, a magnet, a cover or a flexible, preferably elastic, strip. The attachment may also result from a form fit with the mobile phone. For example, the acquisition tool may be attached to a phone case.

[0404] Preferably, however, the mobile phone and the acquisition tool communicate with each other, but are movable independently of each other. Preferably, no rigid device, preferably no mechanism, connects the mobile phone and the acquisition tool together so that the mobile phone can be moved in space, preferably in all dimensions of space, without necessarily dragging the acquisition tool with it.

[0405] Preferably, the screen displays the scene observed by the camera of the acquisition head. The independence of movement between the mobile phone and the acquisition tool makes it possible in particular to use the screen of the mobile phone to view the scene observed by the camera of the acquisition head, without this viewing being hindered by the manipulation of the acquisition head.

[0406] In one embodiment, during acquisition, the user observes the screen of the mobile phone, the mobile phone preferably being stationary relative to the ground, for example placed on a table, and manipulates the acquisition tool. He can thus easily position the acquisition tool in a desired position, preferably for extraoral acquisition. In addition, this embodiment advantageously allows the user to use the camera of the mobile phone arranged on the side opposite the screen, without having to use a mirror.

[0407] Preferably, the user acquires at least one front-view image, preferably at least one image from the user's right, and more preferably at least one image from the user's left.

[0408] Preferably, the user acquires at least one open mouth image and at least one closed mouth image.

[0409] The set of acquired images preferably comprises more than two, preferably more than three, preferably more than 5, preferably more than 6 and / or less than 30, preferably less than 20, preferably less than 15, preferably less than 10 images.

[0410] Preferably, the user uses a tool to free their lips, and better expose the dental arch to the camera of the acquisition tool. The tool can be, for example, a spoon inserted into their mouth.

[0411] In one embodiment, he uses a retractor which he partially inserts into his mouth.

[0412] Preferably, the generalized method comprises, after said acquisition, an analysis of said image in order to define the dental situation of the user, and preferably to design an active or passive orthodontic treatment plan, and / or to verify the proper progress of an active or passive orthodontic treatment in progress.

[0413] Preferably, the acquisition method comprises, after said analysis of said image, the manufacture of an orthodontic appliance, for example an orthodontic splint, and preferably the sending of said orthodontic appliance to the user. The uses mentioned above for the updated images can also be applied to the image or images acquired according to the generalized method.

[0414] Said at least one image is preferably used for

[0415] - detect a recurrence, and / or

[0416] - determine the speed of change in the positioning of the teeth, and / or

[0417] - optimize the date of making an appointment with a dental care professional, and / or

[0418] - evaluate the effectiveness of orthodontic treatment, and / or

[0419] - assess the evolution of the positioning of teeth towards a reference model corresponding to a determined positioning of the teeth, in particular an improved positioning of the teeth, and / or

[0420] - modify an ongoing orthodontic treatment, for example by manufacturing a new series of orthodontic aligners, and / or

[0421] - in dentistry, and / or

[0422] - visualize and / or measure and / or detect dental plaque, and / or caries, and / or micro-cracks, and / or wear, for example resulting from bruxism or the use of an active or passive orthodontic appliance, in particular in the event of breakage or detachment of an orthodontic arch;

[0423] - visualize and / or measure and / or detect a change in volume, in particular during tooth growth or following an intervention by a dental care professional, for example a deposit of glue on the surface of the teeth;

[0424] - assess the appropriateness of interceptive treatment, before any orthodontic treatment, in particular to assess the benefit of orthodontic treatment.

[0425] Figure 12 illustrates a device 6' for implementing such an image acquisition method. This kit comprises a mobile phone 12' and an acquisition tool 31' in communication with the mobile phone, preferably by radio, preferably by Bluetooth® or WiFi. Communication by cable is also possible.

[0426] The acquisition tool 31' is provided with an acquisition head 32' which can be introduced into the user's mouth. The acquisition head comprises a camera 33' which acquires the image and transmits it to the mobile phone 12', or acquires a signal and transfers it to the mobile phone 12' so that the latter generates the image from said signal.

[0427] Preferably, the acquisition tool does not have a physical connection to the mobile phone or is connected to the mobile phone by a flexible connection, for example a cable. Preferably, the acquisition tool has a handle 34' facilitating its handling, by the user himself or one of his relatives, for example in the manner of a toothbrush.

[0428] The mobile phone 12' may include one or more of the features of the mobile phone 12. Preferably, it is not attached to any support, and in particular to any support attached to the user such as the support10 described above, and the user can handle it freely.

Claims

Demands 1. A method for acquiring at least one image of at least one dental arch of a user (U) using a mobile phone (12') and an acquisition tool (31') comprising an acquisition head (32') equipped with a camera (33'), a method wherein the acquisition head: - acquires said image and transmits it to the mobile phone, or - acquires a signal and transfers it to the mobile phone so that said mobile phone generates the image from said signal, autonomously or with the help of a computer with which said mobile phone is in communication, said at least one image being a photo or an image extracted from a film.

2. Method according to the preceding claim, wherein the mobile phone (12') and the acquisition tool (31') are exclusively handled by the user.

3. A method according to any one of the preceding claims, wherein the acquisition is carried out extraorally, the camera of the acquisition tool not penetrating the user's mouth.

4. A method according to any one of claims 1 to 2, wherein the acquisition is carried out intraorally, the camera of the acquisition tool penetrating the user's mouth.

5. A method according to any one of the preceding claims, wherein the mobile phone and the acquisition tool are movable independently of each other.

6. A method according to any one of the preceding claims, wherein, during acquisition, the user observes the mobile phone screen to view the scene observed by the camera of the acquisition head.

7. Method according to the immediately preceding claim, wherein during acquisition, the mobile phone is stationary relative to the ground and the user manipulates the acquisition tool.

8. A method according to any one of the preceding claims, wherein the user acquires at least one image viewed from the front, at least one image from the right of the user, at least one image from the user's left, at least one image with their mouth open, and at least one image with their mouth closed. A method according to any one of the preceding claims, wherein the user uses a tool to retract their lips and better expose the dental arch to the camera of the acquisition tool. A method according to the immediately preceding claim, wherein said tool is a retractor. A method according to any one of the preceding claims, wherein the acquisition tool communicates with the mobile phone via radio waves. A method according to any one of the preceding claims, wherein said at least one image is used to - determine the rate of change of tooth positioning, and / or - optimize the appointment date with a dental care professional, and / or - evaluate the evolution of tooth positioning towards a reference model corresponding to a determined tooth positioning, and / or - to visualize and / or measure and / or detect a microcrack, and / or wear, and / or - to visualize and / or measure and / or detect a change in volume during tooth growth or following an intervention by a dental professional. A method according to any one of the preceding claims, wherein the image is used to generate a three-dimensional digital model.

Images