Extra-oral image taking kit

Abstract

Disclosed is an image taking kit (1) comprising: • an extra-oral image taking device (2) comprising O a support (4) provided with a mouthpiece (9) defining a mouthpiece opening (17), O an image acquisition apparatus (5) attached to the support and comprising a camera (35) for acquiring at least one image of a dental scene seen through the mouthpiece opening (17), and • a display device (3) comprising a screen for displaying an image representing the scene acquired by the image acquisition apparatus, the image acquisition apparatus comprising an additional screen and / or the support defining an image taking chamber (15), the image acquisition apparatus being at least partially, preferably entirely, accommodated in the image taking chamber.

Description

[0001] Description

[0002] Title: Extraoral Photography Kit

[0003] The present invention relates to a kit for taking views of dental scenes from a point of view located outside the mouth and for viewing the corresponding images.

[0004] It is known, for example from WO 2016 / 066651 A1, to monitor the progress of an orthodontic treatment of a patient by comparing the progress of an orthodontic model generated from images of the patient's lower and upper dental arches acquired prior to the implementation of the orthodontic treatment with images of said arches acquired during the orthodontic treatment.

[0005] The acquisition of images of the dental arches can be carried out by means of a shooting device comprising an image acquisition apparatus and a dental retractor. Examples of such shooting devices are described in EP 3 391 810 A1 and in WO 2022 / 008533 A1, which comprise a hollow tubular support, carrying at one end a dental retractor, and at the opposite end of which is mounted a mobile phone equipped with a camera directed towards the patient's mouth to take images of the dental arches. The images can then be transmitted to an orthodontist or a dentist who can analyze them directly or after appropriate digital processing.

[0006] However, the patient who implements the devices of EP 3 391 810 A1 and WO 2022 / 008533 A1 cannot directly observe the images that he is acquiring on the screen of the mobile phone, the camera of the mobile phone being arranged on the face opposite the screen. In addition, to control the taking of a picture, he may have to press the touch screen of the phone. To overcome these problems, he must use a mirror, which is impractical.

[0007] So there is a need to solve this drawback.

[0008] The invention proposes a shooting kit comprising:

[0009] • an extraoral photography device comprising o a support, o a dental retractor defining a retractor opening and carried by the support, o an image acquisition device fixed to the support and comprising a camera for acquiring at least one image of a dental scene seen through the retractor opening, and

[0010] • a display device comprising a screen for displaying an image representing the dental scene and acquired by the image acquisition device, the image acquisition device preferably comprising an additional screen and / or the support defining a shooting chamber, preferably the image acquisition device being at least partially, preferably entirely, housed in the shooting chamber.

[0011] The user of the kit can thus directly view the image acquired by the image acquisition device immediately after acquisition thereof. For example, with the dental retractor positioned in the mouth, the user can easily check the quality, for example the contrast and / or brightness, of the image and / or can move the imaging device relative to his dental arches, so as to acquire an image from another point of view, for example one more suited to representing the dental scene.

[0012] Furthermore, the implementation of the kit according to the invention can make it possible to reduce the light pollution induced by the use of a mirror. Indeed, observation by means of a mirror as described above is generally carried out in a bathroom, where specific and powerful lighting is generally associated with the mirror and can disrupt the acquisition of images.

[0013] An "extraoral" image is acquired by means of the image acquisition device, which in a service configuration in which the dental retractor is inserted into the user's mouth, is such that the image acquisition device is outside the user's oral cavity. An extraoral image is acquired from a position remote from the oral cavity.

[0014] The display device is preferably movable relative to the shooting device.

[0015] The display device may be chosen from a mobile phone, a digital tablet, a desktop computer, particularly a portable computer, or a television, particularly a connected television. The screen of the display device may be touch-sensitive.

[0016] Preferably, the kit comprises a communication module for transferring the images acquired by the image capture device to the display device. The communication module may be a wireless communication module, in particular by radio waves, for example by implementing the Wifi® or Bluetooth® data transfer protocol. In particular, the image capture device may comprise a wave transmitter for sending an image acquired by the image acquisition apparatus and the display device may comprise a wave receiver for receiving said image.

[0017] According to one variant, the communication module comprises a data transmission cable, for example of the USB type, for connecting the image capture device to the display device, and the image capture device and the display device each comprise a connection socket for connecting the data transmission cable.

[0018] Furthermore, the kit may include a control module to trigger image acquisition. The image capture device and / or the display device may include the control module.

[0019] The control module preferably comprises a computer program comprising instructions for guiding the user to position the image capture device in at least one image acquisition position and a processor for executing the computer program. In particular, in the variant in which the acquisition device is housed in the image capture chamber, the control module is housed in the display device.

[0020] The computer program may include instructions for processing the acquired image(s) in order to provide at least one piece of information to the user. The information may be audio, for example in the form of a voice message, in order to position the device relative to the user's dental arches to a predetermined acquisition position and / or orientation, and optionally, specify to the user the number of images to be acquired. Where appropriate, the image-taking device and / or the display device may further include a loudspeaker for broadcasting the information. The information may be visual and may be displayed on the screen, alongside or appearing visually superimposed on the displayed image.

[0021] The information may be chosen from the number of images to be acquired, information relating to the adjustment of the geometry of the support, the orientation of the support and / or a positioning of the user's mouth on the retractor. The computer program may further comprise instructions to require and / or wait for an action from the user, for example in order to trigger the acquisition of an image. For example, after execution by the processor, the computer program may require pressing on an area of ​​the touch screen of the display device. According to another example, it may wait for a voice command from the user. In particular for this purpose, the image-taking device and / or the display device may comprise a microphone.

[0022] The control module may comprise an actuator and be configured to trigger the acquisition of images by the acquisition device following actuation of the actuator. The actuator is for example electrically connected to the acquisition device. The actuator is for example a push button. It may be carried by the support.

[0023] The control module can be configured to detect the presence of a pattern and / or an object in the scene seen by the camera, and to trigger the acquisition of images as soon as the pattern and / or the object is detected. The detection of the pattern and / or the object is carried out, for example, by means of a deep learning algorithm, or a computer vision technique, or computer vision in English.

[0024] The control module is preferably configured to trigger the transfer of the image(s) acquired by the image capture device to the display device. It can be configured so that the transfer of the images is carried out in real time, that is to say in such a way that the screen displays in real time the image acquired by the acquisition device. By real time, it is meant that the duration between the acquisition and the display of an image is less than 1 s, or even less than 500 ms, or even less than 10 ms.

[0025] According to a variant where the display device includes the control module, the control module can in particular send at least one control signal to the shooting device via the communication module.

[0026] The image capture device and / or the display device may include a storage module, for example a hard disk or Flash memory, in order to digitally store the images acquired by the acquisition device.

[0027] The camera may have a focal length of between 25 mm and 90 mm, preferably between 30 mm and 45 mm. The focal length of the camera may be fixed, which advantageously allows the implementation of a compact camera. In one variant, the camera may include a focusing system by varying the focal length, of the “autofocus” type.

[0028] The camera may extend along an axis parallel to, or even coincident with, the longitudinal axis of the support. The camera's viewing axis may be parallel to, or even coincident with, the longitudinal axis of the support.

[0029] The image acquisition device may include, or even consist of, several cameras. The cameras may be arranged along different viewing axes, and each may acquire different views of the same dental scene. The image acquisition device may thus provide a stereoscopic view of the dental scene. The cameras may have the same focal length.

[0030] The image acquisition device may be fixed relative to the dental retractor. Thus, the imaging device allows for imaging under similar conditions at different times during the orthodontic procedure. Similar acquisition conditions include the position and relative orientation of the image acquisition device relative to the patient's teeth. Alternatively, the image acquisition device may be movable relative to the dental retractor.

[0031] The support may include a longitudinally extending hollow support portion and the dental retractor may extend the hollow support portion. The hollow support portion may be grippable. The hollow support portion may include shaped reliefs and / or depressions to ensure optimal grip of the imaging device.

[0032] The shooting device is shaped such that in the service configuration, the hollow support portion is at least partly, preferably entirely, outside the user's mouth.

[0033] The hollow support portion may be made of cardboard or, preferably, of a thermoplastic material.

[0034] The hollow support portion may have the shape of a housing extending longitudinally and opening substantially outwards only through the spacer opening, and optionally through a ventilation opening, for example longitudinally opposite the spacer opening. The ventilation opening facilitates the evacuation of the mist produced by the user, in the service configuration of the shooting device. The hollow support portion may have a substantially cylindrical shape.

[0035] The hollow support portion may comprise a bottom wall, for example solid, longitudinally opposite the spacer opening. The image acquisition device may be in contact with, in particular fixed to, the bottom wall.

[0036] The hollow support portion can be sandwiched between the dental retractor and the image acquisition device.

[0037] Preferably, the hollow support portion defines the shooting chamber. Alternatively, the image acquisition apparatus, preferably according to the second embodiment described below, the image acquisition apparatus is remote from the shooting chamber.

[0038] The length of the hollow support portion, measured along the longitudinal axis, is less than 15 cm, preferably less than 10 cm.

[0039] At least the hollow support portion, or even the support itself, can be telescopic, that is, its length, measured along its longitudinal axis, is variable. For example, it is formed of several pieces sliding into each other.

[0040] According to a variant, the support further comprises a grippable support portion which is mounted on the hollow support portion, the device then being able to be manipulated by gripping the grippable support portion.

[0041] The grippable support portion may longitudinally extend the hollow support portion and project transversely therefrom.

[0042] Preferably, the hollow support portion is disposed between the dental retractor and the grippable support portion.

[0043] The hollow support portion may be fixed, for example removably, to the grippable support portion. Preferably, the grippable support portion and the hollow support portion form a monolithic assembly.

[0044] The grippable support portion may define a cavity and include a cover closing the cavity. The device may include a printed circuit and / or a battery controlling and / or electrically powering the image acquisition device, and which are preferably housed in the cavity. The cavity may further be made waterproof, in particular by means of one or more seals. Furthermore, the battery may be autonomous. It may be electrically charged by induction, or by a wired connection, for example of the USB type. It may be powered directly by a fixed electrical connection to an external power source.

[0045] The hollow support portion and / or the grippable support portion may be covered at least in part by a flexible material making it easier to hold, for example a thermoplastic elastomer called “TPE”, in particular a thermoplastic rubber called “TPR”, such as styrene-butadiene-styrene, a thermoplastic polyurethane called “TPU”.

[0046] The dental retractor is preferably shaped to move, and preferably curl, the upper and lower lips of the user upwards and downwards respectively, in an operating configuration of the imaging device in which the dental retractor is inserted into the mouth of the user of the imaging device, so as to maximize the dental surface visible by the image acquisition apparatus. By "upward" and "downward" are meant the directions along a vertical axis when the user of the imaging device is standing.Preferably, the dental retractor is shaped so that, when in at least one position of the operating configuration of the camera device in which the dental retractor is introduced into the user's mouth, the upper and lower lips are moved, preferably curled, upwards and downwards respectively in such a way that at least the incisors, and preferably at least part of the canines and / or molars, of the upper and lower dental arches respectively are visible to the camera.

[0047] The dental retractor may be made of a single material with the support, in particular with the hollow support portion. In other words, the dental retractor and the support, in particular the hollow support portion, may be obtained jointly during the same manufacturing operation. The hollow support portion and the dental retractor may be obtained by molding and / or by additive manufacturing.

[0048] Alternatively, the dental retractor may be mounted on the hollow support portion. It may be fixed to the support, in particular to the hollow support portion. For example, it is snapped, screwed or glued onto the support, in particular to the hollow support portion. Alternatively, the dental retractor may be removably mounted on the support, in particular to the hollow support portion, for example by magnetic coupling, by means of a hook-and-loop strip, or by form-fitting between the support, in particular the hollow support portion, and the dental retractor. Advantageously, it is possible to mount on the support, in particular to the hollow support portion, different retractors of various sizes and thus to choose the dental retractor best suited to the morphology of the mouth of each user.

[0049] Preferably, the surface area covered by the spacer opening is greater than 2 cm 2, preferably greater than 3 cm 2 , preferably greater than 5 cm 2 , preferably greater than 10 cm 2 , or even greater than 15 cm 2 , for example about 19 cm 2 . Preferably, it is less than 30 cm 2 , preferably less than 25 cm 2 . Said area is measured transversely to the longitudinal axis. The contour of the spacer opening can be delimited by observing the imaging device along the longitudinal axis, from a position opposite the image acquisition device along the longitudinal axis.

[0050] The imaging device may include a mirror attached to the support such that the image acquisition apparatus acquires a composite image including a direct image of the retractor opening and an image of the retractor opening reflected by the mirror. Thus, in the service configuration, the image acquisition apparatus sees a composite image including a direct image of the teeth viewed directly through the retractor opening and a reflected image of the teeth returned by the mirror.

[0051] Furthermore, the shooting device may comprise a light source arranged to illuminate through the spacer opening.

[0052] The light source may include at least one lamp, in particular one with light-emitting diodes, and / or a flash.

[0053] The light source is preferably placed in the camera.

[0054] The imaging device may include a control module for controlling the properties of the radiation emitted by the light source, in particular as a function of the light radiation received through the spacer opening. For example, the control module may be configured so that more than 50%, more than 90%, or even substantially 100% of the radiation received through the spacer opening comes from the light source.

[0055] In particular, the shooting device may comprise several light sources and several cameras, each light source being arranged to illuminate the optical field of a corresponding camera. The light source(s) may be housed in the housing.

[0056] In order to determine the color and / or translucency of the user's teeth, the imaging device may comprise a colorimetric target and / or a translucency target respectively, fixed to the support, the image acquisition device seeing said target(s).

[0057] Furthermore, the imaging device may further comprise one or more additional cameras intended, in at least one configuration of the imaging device, to be arranged in the user's oral cavity to acquire at least one intraoral view of the lower dental arch and / or the upper dental arch, facilitating, for example, the imaging of the lingual surfaces of the teeth, the interdental spaces, the control of caries or the control of the palate. In particular, the imaging device may comprise a telescopic arm between a folded configuration and at least one unfolded configuration, the additional camera being mounted on the telescopic arm. Preferably, in the folded configuration, the additional camera(s) are entirely housed in the support.Preferably, in the service configuration of the imaging device and in the unfolded position of the arm, the additional camera(s) are arranged in the oral cavity of the user to acquire at least one intraoral view of the lower dental arch and / or the upper dental arch.

[0058] Furthermore, in a first embodiment described below, the image acquisition device is housed, at least in part, in the shooting chamber. Preferably, it also has a volume of less than 40 cm 3 . In addition to the characteristics described above, according to this first embodiment, the kit may have any of the following characteristics.

[0059] Preferably, the camera is less than 15 cm, preferably less than 7 cm, preferably less than 6 cm and preferably more than 2.5 cm from the dental retractor.

[0060] The dental retractor defines an upper bearing surface and / or a lower bearing surface intended to contact and move the lower lip and / or the upper lip of the user respectively in the operating position of the device in which the retractor is introduced into the user's mouth. The distance between the dental retractor and the image acquisition device is the smallest distance separating the lower bearing surface of the dental retractor and the image acquisition device or separating the upper bearing surface of the dental retractor and the camera.

[0061] The image acquisition device may include an additional screen. Preferably, the image acquisition device does not have an additional screen and / or a telephone communication unit. Preferably, the image acquisition device is not embedded in a mobile phone. Preferably, the image acquisition device is different from a mobile phone.

[0062] In a second embodiment, the image acquisition apparatus comprises an additional screen. In addition to the features described above, according to this second embodiment, the kit may have any of the following features.

[0063] In particular, the shooting device may be as described in EP 3 391 810 A1 or in WO 2022 / 008533 A1.

[0064] In particular, the image acquisition device may be a mobile phone. The mobile phone may digitally store the computer program described above.

[0065] Preferably, the image acquisition device is removably mounted on the support. In particular, prior to its mounting on the support, the acquisition device may be configured to detect the support, for example at a distance of less than 10 cm, so as to trigger the execution of the computer program.

[0066] For example, the support includes a detection member, for example an RFID chip or an NFC chip, detectable by the image acquisition device.

[0067] The display device may be configured to disable the display on the additional screen. In the variant where the image acquisition device is a mobile telephone, the display device may be configured to disable access to the mobile telephone network, in order to prevent the user from being interrupted by a telephone call during image acquisition.

[0068] The kit according to the second embodiment may include any of the features of the kit according to the first embodiment, and vice versa.

[0069] Furthermore, the invention also relates to a method for taking extraoral images using the image-taking kit according to the invention, the method comprising a) gripping the support and positioning the dental retractor in the mouth of a user, b) acquiring at least one image of the lower dental arch and / or the upper dental arch of the user by the image acquisition device, and c) displaying the image on the display device which is visible to the user.

[0070] The positioning of the image acquisition device is thus greatly facilitated, since the user thus directly views the image which is acquired by the image acquisition device. The operator, who may be the user, can thus move the support to a desired and / or optimal acquisition position while viewing on the display device the corresponding image(s) of the dental arches. Preferably, the method further comprises the movement, for example by the user, of the image-taking device relative to the user's mouth following observation of the image displayed on the screen.

[0071] In step a), the positioning of the dental retractor allows the user's lower and upper lips to be separated from each other to improve the visibility of the lower and upper dental arches respectively.

[0072] Gripping and / or positioning of the support can be carried out by an operator other than the user.

[0073] In step b), the user may be guided by the execution of the computer program as described above. The acquisition may be triggered automatically following the introduction of the dental retractor into the user's mouth. The method may include measuring the light intensity in the imaging chamber, and triggering the acquisition of the images when the light intensity is below a predetermined minimum light intensity.

[0074] The acquisition of the image can be triggered by the user or by an operator other than the user, for example in response to information provided by the control module. The user can trigger the acquisition by issuing a control command read by the image-taking device and / or the display device. The control command is, for example, the actuation of a push button fixed to the support, or a pressure on a touch screen of the display device.

[0075] Several images can be acquired in step b). They can be acquired in series, that is to say that the image acquisition device acquires successively, and in particular according to a fixed acquisition frequency, the images following a single triggering of the acquisition. The images can be displayed according to step c) in real time on the display device.

[0076] Preferably, the display device is separated from the image acquisition device by a distance of less than 5 m, or even less than 1 m, and preferably greater than 20 cm.

[0077] Preferably, the method comprises processing the image(s) acquired at a position of the image acquisition apparatus and generating information, preferably intended for the user. Preferably, the information is displayed by the display device.

[0078] The invention can be better understood by reading the detailed description which follows and the attached drawing in which:

[0079] [Fig. 1] represents an example of a shooting kit according to the invention,

[0080] [Fig. 2] is a perspective view of an example of a shooting device,

[0081] [Fig. 3] is a sectional view along a longitudinal plane of the shooting device of Figure 2,

[0082] [Fig. 4] and [fig. 5] are perspective views from different observation points of another example of a shooting device,

[0083] [Fig. 6] schematically illustrates an example of implementation of the image acquisition method using the kit according to the invention.

[0084] Detailed description

[0085] Figure 1 illustrates an example of a camera kit 1 according to the invention. The kit 1 comprises a camera device 2 and a display device 3. The camera device 2 comprises a support 4 and an image acquisition device 5. The image acquisition device 5 may have a volume of less than 40 cm 3 , resulting in a particularly compact shooting device.

[0086] The support 4 comprises a hollow support portion 7. The device also comprises a dental spacer 9.

[0087] The hollow support portion 7 has a generally tubular and elongated shape extending along a longitudinal axis X. It comprises a hollow tubular part 11 and a bottom wall 13 which closes a longitudinal end of the tubular part. The tubular part 11 and the bottom wall 13 delimit a camera chamber 15 in which the image acquisition device 5 is housed.

[0088] The bottom wall 13 may be solid or may have ventilation openings passing right through its thickness, for example in the form of cylindrical holes and / or grooves. In a variant, the hollow support portion 7 may be free of such a bottom wall.

[0089] At least a portion of the tubular portion 11, or even the entire tubular portion as illustrated, preferably extends parallel to the longitudinal axis X, to facilitate the holding and handling of the hollow support portion.

[0090] The tubular portion 11 has at least one cross-section to the longitudinal axis X having a substantially oblong general shape. Such a shape of the hollow support portion facilitates the gripping of the support and furthermore corresponds substantially to the shape of the contour of the access opening to the oral cavity of a user, which is delimited by the lower and upper lips when the user moves his lower and upper jaws apart from each other.

[0091] The tubular part 11 opens through another end longitudinally opposite the bottom wall, into a spacer opening 17.

[0092] The contour 19 of the spreader opening has a saddle shape. In other words, when observed in two perpendicular directions which are themselves orthogonal to the longitudinal direction, the contour 19 of the spreader opening 17 has two convex parts 21 opposite each other and connected to each other by concave parts 23 opposite each other.

[0093] The shape of the retractor opening is preferably adapted to the general shape of the user's dental arches.

[0094] The dental retractor 9 is fixed to the hollow support portion 7. In the example illustrated, it is integral with the hollow support portion. Other configurations may be envisaged, the dental retractor being, for example, made of a different material than the hollow support portion and / or being mounted on the hollow support portion.

[0095] The dental retractor 9 comprises two portions 25a-b rigidly connected to each other, preferably symmetrical to each other with respect to a median plane, which respectively define an inner bearing surface 27a and an outer bearing surface 27b, to come into contact and move the lower lip and / or the upper lip of the user respectively in the service position of the device in which the dental retractor is introduced into the user's mouth.

[0096] The dental spacer 9 is a rim which projects from the tubular part 11, radially outwards, from the longitudinal end of the tubular part opposite the bottom wall 13.

[0097] The rim is annular in shape, deformed into a horse saddle. The contour of the rim is homothetic to the contour of the spreader opening.

[0098] The image acquisition apparatus 5 may be attached to the support 3. For example, as illustrated in FIGS. 2 and 3, the support comprises a receptacle 28 which defines a housing 29 of complementary shape to the image acquisition apparatus 5 and in which the image acquisition apparatus is received.

[0099] The receptacle comprises a receptacle wall 31, for example of semi-cylindrical shape, which extends transversely between the opposite inner faces of the tubular part and longitudinally from the bottom wall of the hollow support portion.

[0100] The receptacle is integral with the hollow support portion. Alternatively, it can be attached to the hollow support portion.

[0101] The image acquisition apparatus comprises a housing 33 and two optical assemblies 34, each including a camera 35 and an LED lamp 37, which are entirely housed in the housing. This number of cameras and lamps is not limiting.

[0102] The image acquisition device 5 further comprises a USB type connection socket 39, arranged in a recess made in the thickness of the bottom wall 13. The socket allows the connection of a data transfer cable to transmit the images taken through the spacer opening 17 by the cameras 35 to the display device 3.

[0103] Figures 3 and 4 illustrate a variant of the image-taking device 3, as described in EP 3 391 810 A1, in which the dental retractor 9 is removably mounted on the support 4, which can also be telescopic, and the image acquisition device 5 is a mobile phone 40 provided with a screen 42 removably mounted on the support and not directly visible to the user when the dental retractor is introduced into the user's mouth. In the example illustrated, the display device 3 is a digital tablet 44 comprising a screen 46, a digital data storage memory in which is loaded in particular a computer program to guide the acquisition of images by means of the image-taking device 2 and a processor to execute the computer program. However, other types of display devices 3 can be envisaged.For example, the display device is a personal computer, a mobile phone, or a connected television, also known as a “smart TV.” In particular, the display device may be a mobile phone and the acquisition device may be another mobile phone.

[0104] The transfer of images between the shooting device and the display device can be carried out by means of a cable connected by one of its ends to the connection socket 39 of the shooting device of figure 2 or by that of the mobile telephone, and by the other of its ends, to the connection socket of the digital tablet. Alternatively, the data, and in particular the images, can be transferred by wireless connection, for example by WIFI, between the shooting device and the display device.

[0105] Figure 5 illustrates an example of implementation of the method according to the invention using the shooting kit according to the invention, for example as illustrated in Figures 1 to 4.

[0106] In order to acquire images of his dental arches, the user 50 takes the support 4 in hand and introduces the dental retractor into his mouth, in order to curl his lips and free his arches so that they are visible by the image acquisition device 5 through the retractor opening.

[0107] It can further control the execution of the computer program on the display device. For example, the execution of the program triggers the acquisition of images by the image acquisition apparatus 5 and the real-time transfer of said images to the acquisition device via a connection cable 52. The user can thus directly view the image acquired by the image-taking device 2 as indicated by the arrow V on the screen 46. As illustrated, the method can be implemented simply and comfortably for the user. Following the acquisition of the image, the user can manipulate the support 4 in order to modify the position and orientation of the image acquisition apparatus relative to his face to acquire new images which he can again view directly on the screen 46 and in order to evaluate the quality of the acquisition.

Claims

Claims 1) Shooting kit (1) including: • an extraoral imaging device (2) comprising o a support (4), o a dental retractor (9) defining a retractor opening (17) and carried by the support, o an image acquisition device (5) fixed to the support and comprising a camera (35) for acquiring at least one image of a dental scene seen through the retractor opening (17), and • a display device (3) comprising a screen (46) for displaying an image representing the scene acquired by the image acquisition device, the image acquisition device comprising an additional screen (42) and / or the support defining a camera chamber (15), the image acquisition device being at least partially, preferably entirely, housed in the camera chamber. 2) Kit according to claim 1, the display device being chosen from a mobile phone, a digital tablet, a desktop computer, in particular a transportable one, a television in particular a connected one. 3) Kit according to any one of claims 1 and 2, comprising a communication module for transferring the images acquired by the image capture device (2) to the display device (3). 4) Kit according to the preceding claim, the communication module being a wireless communication module, in particular by radio waves. 5) Kit according to claim 3, the communication module comprising a data transmission cable (52), for example of the USB type, for connecting the image capture device (2) to the display device (3), and the image capture device and the display device each comprise a connection socket for connecting the data transmission cable. 6) Kit according to any one of the preceding claims, comprising a control module for triggering the acquisition of images. ) Kit according to the preceding claim, the control module comprising a computer program comprising instructions for guiding the user to position the image-taking device in at least one image acquisition position and a processor for executing the computer program. ) Kit according to the preceding claim, the computer program comprising instructions for processing the acquired image(s), in order to provide at least one piece of information to the user. ) Kit according to any one of the preceding claims, the image acquisition apparatus may comprise several cameras (35), in particular arranged along different view axes and each for acquiring different views of the same dental scene. 0) Kit according to any one of the preceding claims, the image acquisition apparatus having a volume of less than 40 cm 3. 1) Kit according to any one of the preceding claims, the surface area covered by the spacer opening being greater than 2 cm 2. 2) Kit according to any one of the preceding claims, the support comprising a hollow support portion (11) extending longitudinally, the dental retractor (9) extending the hollow support portion. 3) Kit according to the preceding claim, the dental retractor (9) being integral with the hollow support portion or being mounted, in particular removably, on the hollow support portion (11). 4) Kit according to any one of the preceding claims, the camera (35) being less than 15 cm, preferably less than 7 cm, preferably less than 6 cm and preferably more than 2.5 cm from the dental retractor (9). 5) Kit according to any one of the preceding claims, the image acquisition apparatus (5) not being embedded in a mobile phone and / or being different from a mobile phone.6) Kit according to any one of claims 1 to 13, the image acquisition device comprising an additional screen (42), in particular the image acquisition device being a mobile phone (40). 7) Method for taking extraoral images using the image acquisition kit according to any one of the preceding claims, the method comprising. a) gripping the holder (4) and positioning the dental retractor (9) in the mouth of a user (50), b) acquiring at least one image of the lower dental arch and / or the upper dental arch of the user by the image acquisition apparatus (5), and c) displaying the image on the display device (3) which is visible to the user (50).

Images