Extraoral imaging device

Abstract

Extraoral imaging device. Extraoral imaging device (1) comprising: - a support (3) having a hollow support portion (7), - a dental retractor (9) carried by the hollow support portion, the dental retractor defining a retractor opening (17), the area of ​​the surface covered by the retractor opening being greater than 2 cm², - an image acquisition device (5) for taking images through the retractor opening, the hollow support portion (7) delimiting a camera chamber (15), the image acquisition device (5) being at least partially, preferably entirely, housed within the camera chamber. Figure for the abbreviation: Fig. 1

Description

Title of the invention: Extraoral imaging device

[0001] The present invention relates to a device for imaging dental arches.

[0002] It is known, for example from WO 2016 / 066651 A1, to monitor the progress of a patient's orthodontic treatment by comparing the evolution of an orthodontic model generated from images of the patient's lower and upper dental arches acquired prior to the implementation of orthodontic treatment with images of said arches acquired during the orthodontic treatment.

[0003] The acquisition of images of the dental arches can be carried out using a camera equipped with an image acquisition device and a dental retractor.

[0004] Examples of such imaging devices are described in EP 3 391 810 A1 and in WO 2022 / 008533 A1, which carry a mobile phone equipped with a camera for taking pictures of dental arches.

[0005] However, a mobile phone is bulky and can make it difficult to handle these devices once the dental retractor has been inserted into the user's mouth.

[0006] There is therefore a permanent need for a new device for taking extraoral images of dental arches, in particular one that is easy to handle.

[0007] The invention relates to an extraoral imaging device, comprising

[0008] - a support comprising a hollow support portion,

[0009] - a dental retractor carried by the hollow support portion, the dental retractor finishing a spreader opening, and

[0010] - an image acquisition device for taking images through the aperture of spreader.

[0011] According to a first aspect of the invention, the area of ​​the surface covered by the gap opening is greater than 2 cm2, and the hollow support portion delimits a camera chamber, the image acquisition device being at least partially, preferably entirely, housed in the camera chamber.

[0012] The device according to the first aspect of the invention is thus easily handled. Since the acquisition device is at least partially located in the camera chamber, it hinders the handling of the device little or not at all during shooting.

[0013] According to a second aspect of the invention, the image acquisition device is preferably fixed on the support, preferably on the hollow portion of the support, and comprises a camera, preferably less than 15 cm away, better less than 7 cm away, from the dental retractor.

[0014] As will become clearer in the rest of the description, the device According to the second aspect of the invention, it is advantageously compact, resulting in particular from the short distance separating the image acquisition device from the dental retractor, which makes it easily manipulable.

[0015] The device according to the first aspect of the invention preferably has the characteristics of the device according to the second aspect of the invention and vice versa.

[0016] Furthermore, the device according to the invention, and in particular according to any one of its first and second aspects, may include one or more of the optional features described below.

[0017] The dental retractor defines an upper support surface and / or a lower support surface intended to contact and move the user's lower lip and / or upper lip, respectively, into the device's operating position in which the retractor is inserted into the user's mouth. The distance between the dental retractor and the image acquisition device is the smaller of the distances between the lower support surface of the dental retractor and the image acquisition device or between the upper support surface of the dental retractor and the camera.

[0018] Extraoral images are acquired using the device according to the invention, which, in a service configuration where 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 distant from the oral cavity.

[0019] The image acquisition device is preferably positioned less than 6 cm from the dental retractor. It is preferably positioned between 2.5 cm and 6 cm from the dental retractor. This increases the resolution of the images acquired by the image acquisition device. Furthermore, when the device is positioned for occlusal imaging, the risk of it striking the user's face, for example, their nose, is reduced.

[0020] The volume occupied by the image acquisition device is preferably less than 40 cm3, preferably less than 20 cm3, or even less than 10 cm3.

[0021] The mass of the image acquisition device is preferably less than 50 g, preferably less than or equal to 30 g.

[0022] Preferably, the length of the hollow support portion, measured along the longitudinal axis, is less than 10 cm.

[0023] The image acquisition device may be without a screen and / or a telephone communication module. Preferably, the image acquisition device is not embedded in a mobile phone. Preferably, the image acquisition device is different from a mobile phone.

[0024] The image acquisition device includes, or even consists of, at least one camera for taking images through the spreader opening.

[0025] The camera may have a focal length between 25 mm and 90 mm, preferably between 30 mm and 45 mm.

[0026] Preferably, the camera's focal length is fixed, which advantageously allows for the implementation of a compact camera. In one embodiment, the camera may include a focusing system by varying the focal length, of the "autofocus" type.

[0027] The camera can extend along an axis parallel to, or even coinciding with, the longitudinal axis of the support. The camera's viewing axis can be parallel to, or even coinciding with, the longitudinal axis of the support.

[0028] According to one embodiment, the image acquisition device may comprise, or even consist of, at least two cameras. The cameras may be arranged along different viewing axes, each acquiring different views of the same dental scene. The image acquisition device can thus provide a stereoscopic view of the dental scene. The cameras may have the same focal length.

[0029] The image acquisition device can be fixed relative to the dental retractor. Thus, the device allows images to be taken under similar conditions at different times during the orthodontic procedure. "Similar conditions" of acquisition include the position and relative orientation of the image acquisition device with respect to the patient's teeth. In an alternative embodiment, the image acquisition device can be mobile relative to the dental retractor.

[0030] The image capture device may include a connection module for transferring the images acquired by the image acquisition device, for example to a digital image storage unit, for example a Flash memory. In one embodiment, the image capture device may include the image storage unit.

[0031] The connection module can be fixed to the support, in particular to the hollow portion of the support, for example glued to a wall of the support.

[0032] Alternatively, the image acquisition device may include the connection module. In particular, the image acquisition device may include a housing in which the camera(s) and the connection module are housed. The camera(s) and the connection module may be attached to each other.

[0033] The connection module may include a connection socket for a data transfer cable, for example a USB® cable, or such a data transfer cable, or is a remote data transfer module, for example implementing the Wifi® or Bluetooth® data transfer protocol.

[0034] For example, the connection module is a connection socket for a data transfer cable, for example a USB® socket. The support may extend along a longitudinal axis and have an opening, for example axial or transverse, by which the connection socket opens out of the support, in particular out of the hollow portion of the support.

[0035] The hollow support portion can extend longitudinally and the dental retractor can extend the hollow support portion.

[0036] The hollow support portion may be made of cardboard or, preferably, of a thermoplastic material. The device is shaped such that, in the operating configuration, the hollow support portion is at least partially, and preferably entirely, outside the user's mouth.

[0037] The hollow support portion can be grasped. It can have raised and / or hollow shapes designed to ensure optimal grip on the device.

[0038] The hollow support portion may include a back wall, for example a solid one, positioned longitudinally opposite the spreader opening. The image acquisition device may be in contact with the back wall and, in particular, fixed to the back wall.

[0039] The hollow support portion may be shaped like a longitudinally extending housing that opens substantially to the outside 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 condensation produced by the user in the device's operating configuration. The hollow support portion may be substantially cylindrical in shape.

[0040] The hollow support portion may have a wall, preferably opaque, which delimits the camera chamber. It may be substantially tubular.

[0041] According to one variant, the support further comprises a graspable support portion which is mounted on the hollow support portion, the manipulation of the device can then be carried out by grasping the graspable support portion.

[0042] The graspable support portion can extend longitudinally from the hollow support portion and protrude transversely from it.

[0043] Preferably, the hollow support portion is arranged between the dental retractor and the graspable support portion.

[0044] The hollow support portion can be fixed, for example removably, onto the graspable support portion. Preferably, the graspable support portion and the hollow support portion form a monolithic unit.

[0045] The graspable support portion may define a cavity and include a cover sealing the cavity. The device may include an electronic board comprising a printed circuit board and / or a battery controlling and / or powering the image acquisition device, preferably housed within the cavity. The cavity may also be made watertight, in particular by means of one or more seals.

[0046] Furthermore, the battery can be autonomous. It can be electrically charged by induction, or via a wired connection, for example USB. It can be powered directly by a wired electrical connection to an external power source.

[0047] The hollow support portion and / or the graspable support portion may be covered at least in part by a flexible material facilitating its handling, for example a thermoplastic elastomer called "TPE", in particular a thermoplastic rubber called "TPR", such as styrene-butadiene-styrene, a thermoplastic polyurethane called "TPU".

[0048] The dental retractor is preferably shaped to displace, and preferably curl, the upper and lower lips of the user, respectively, upwards and downwards, in a device service configuration in which the dental retractor is inserted into the user's mouth so as to maximize the tooth surface visible to the imaging device. "Upward" and "downward" refer to the directions along a vertical axis when the user is standing.Preferably, the dental retractor is shaped so that, when in at least one position of the camera's service configuration in which the dental retractor is inserted into the user's mouth, the upper and lower lips are displaced, preferably curled up, 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.

[0049] The dental retractor may be a rim, in particular annular or part-ring shaped, extending radially outwards from one end of the hollow support portion, and for example transversely to said portion. "Radially outwards" means that the tubular portion extends away from the longitudinal axis of the device in a plane transverse to that axis. The rim may be rigid or elastically deformable. In particular, it may be made of a material having a Young's modulus less than or equal to the Young's modulus of the material of the hollow support portion.

[0050] Furthermore, the dental retractor can be formed from the same material as the support, and in particular from the graspable portion of the support. In other words, the dental retractor and the graspable portion of the support can be produced together during the same manufacturing operation. The graspable portion of the support and the dental retractor can be obtained by molding and / or by additive manufacturing.

[0051] According to one embodiment, the dental retractor can be mounted on the hollow support portion. It can be fixed to the hollow support portion. The dental retractor can be rigidly fixed to the hollow support portion. For example, it is snapped, screwed, or glued to the grippable part. Alternatively, the retractor The dental retractor can be removably mounted on the hollow support portion, for example, by magnetic coupling or using a hook-and-loop fastener, or by complementary shape between the hollow support portion and the dental retractor. Advantageously, it is possible to mount different retractors of varying sizes on the grippable support portion, thus allowing the selection of the dental retractor best suited to the morphology of each user's mouth.

[0052] Preferably, the area covered by the spreader opening has an area greater than 3 cm², preferably greater than 5 cm², preferably greater than 10 cm², or even greater than 15 cm², for example, approximately 19 cm². Preferably, it is less than 30 cm², preferably less than 25 cm². This area is measured transversely to the longitudinal axis. The outline of the spreader opening can be delineated by observing the imaging device along the longitudinal axis from a position opposite the image acquisition device along the longitudinal axis.

[0053] The device may include a mirror fixed to the support such that the image acquisition device acquires a composite image comprising a direct image of the retractor opening and an image of the retractor opening reflected by the mirror. Thus, in the operating configuration, the image acquisition device sees a composite image comprising a direct image of the teeth observed directly through the retractor opening and a reflected image of the teeth returned by the mirror.

[0054] Furthermore, the device may include a light source arranged to illuminate through the spacer opening.

[0055] The light source may include at least one lamp, in particular a light-emitting diode lamp, and / or a flash.

[0056] The light source is preferably located in the camera chamber.

[0057] The device may include a control module to control the properties of the radiation emitted by the light source, particularly as a function of the light radiation received through the spreader aperture. For example, the control module may be configured so that more than 50%, more than 90%, or even substantially 100% of the radiation received by the spreader aperture comes from the light source.

[0058] In particular, the device may include 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 within the casing.

[0059] In order to determine the color and / or translucency of the user's teeth, the device may include a colorimetric target and / or a translucency target respectively, fixed on the support, the image acquisition device seeing said target(s).

[0060] The device may include a control module to control the acquisition images.

[0061] The control module may include an actuator and be configured to trigger image acquisition by the acquisition device following actuation of the actuator. The actuator is, for example, electrically connected to the acquisition device.

[0062] The actuator is, for example, a push button. It can be supported by the support.

[0063] The control module may include a memory storing a computer program and a processor to execute the computer program, the computer program including instructions to guide the user, for example by emitting a voice message, in order to position the device relative to the patient's teeth to a predetermined acquisition position and / or orientation, and optionally, specify to the user the number of images to be acquired.

[0064] The control module can be housed in the camera chamber.

[0065] Alternatively, the camera system can communicate, for example by a wireless or cable connection with a control device, for example a mobile phone or personal computer, comprising a control module as described above.

[0066] Furthermore, the imaging device may also include one or more additional cameras intended, in at least one configuration of the device, to be positioned 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, imaging of the lingual surfaces of the teeth, interdental spaces, caries screening, or palate examination. In particular, the imaging device may include a telescopic arm between a folded configuration and at least one extended configuration, with the additional camera mounted on the telescopic arm. Preferably, in the folded configuration, the additional camera(s) are entirely housed within the support.Preferably, in the service configuration of the imaging device and in the extended position of the arm, the additional camera(s) are positioned in the user's oral cavity to acquire at least one intraoral view of the lower dental arch and / or the upper dental arch.

[0067] Other features and advantages of the invention will become apparent from the detailed description that follows and the accompanying drawing in which:

[0068] [Fig.1] and [Fig.2] are perspective views from different observation points and axes of observation of a first example of an extraoral viewing device according to the invention,

[0069] [Fig.3] is a view along the longitudinal axis of the device illustrated in [Fig.1],

[0070] [Fig.4] is a cross-sectional view along plane (AA) shown in [Fig.2],

[0071] [Fig.5] and [Fig.6] are a side view, along axes normal to the longitudinal axis, of the device,

[0072] [Fig.7] is a cross-sectional view along plane (BB) shown in [Fig.5],

[0073] [Fig.8] is a cross-sectional view along a longitudinal median plane of a second example of an embodiment of the device support according to the invention,

[0074] [Fig.9] is a view along the longitudinal axis and through the spreader opening of the illustrated support on [Fig.8],

[0075] [Fig. 10] is a perspective view of a third example of an extraoral viewing device according to the invention,

[0076] [Fig. 11] and [Fig. 12] are perspective views from different observation points and axes of observation of a fourth example of an extraoral viewing device according to the invention, and

[0077] [Fig. 13] and [Fig. 14] are side and top views of the fourth example.

[0078] A first example of an extraoral imaging device 1 according to the invention is illustrated in figures 1 to 7.

[0079] The device comprises a support 3 and an image acquisition device 5.

[0080] The support 3 includes a hollow support portion 7. The device further includes a dental retractor 9.

[0081] The hollow support portion 7 has a generally elongated shape extending along a longitudinal axis X. It comprises a hollow tubular section 11 and a bottom wall 13 that closes one longitudinal end of the tubular section. The tubular section 11 and the bottom wall 13 define a camera chamber 15 in which the image acquisition device 5 is housed.

[0082] The back wall 13 may be solid, or may have ventilation openings passing through its entire thickness, for example in the form of cylindrical holes and / or grooves. In one embodiment, the grippable support portion 7 may be free of such a back wall.

[0083] At least part of the tubular part 11, or even the entire tubular part as illustrated, preferably extends parallel to the longitudinal axis X, to facilitate holding and handling the hollow support portion, which is thus also graspable.

[0084] The tubular portion 11 has at least one transverse section S to the longitudinal axis X having a generally oblong shape, delimited by the dashed outline in [Fig. 3]. Such a shape of the hollow support portion facilitates gripping the support and also corresponds substantially to the shape of the contour of the opening providing access to a user's oral cavity, which is delimited by the lower and upper lips when the user separates their lower and upper jaws from each other.

[0085] The tubular part 11 opens through another end opposite longitudinally to the bottom wall, onto a spacer opening 17.

[0086] The contour 19 of the spreader opening has a saddle-like shape. In other words, when viewed from two perpendicular directions orthogonal to the longitudinal direction, as illustrated in Figures 5 and 6, the contour 19 of the retractor opening 17 presents two convex portions 21 opposite each other and connected by concave portions 23 opposite each other.

[0087] The shape of the retractor opening is preferably adapted to the general shape of the user's dental arches.

[0088] Preferably, when viewed along the longitudinal axis, the maximum width lmax of the spacer opening is between 60 mm and 70 mm and the minimum width lmin of the spacer opening is between 28 mm and 40 mm. "Maximum width" and "minimum width" are respectively the diameter of the smallest circle circumscribed around the contour of the retractor opening and the diameter of the large small circle inscribed in the contour of the retractor opening 17. Preferably, when viewed along an axis perpendicular to the longitudinal axis, the height H of the contour of the retractor opening, measured along the longitudinal axis, is between 8 mm and 14 mm.

[0089] The dental retractor 9 is fixed to the hollow support portion 7. In the illustrated example, it is made of the same material as the hollow support portion. Other conformations can be envisaged, the dental retractor being, for example, made of a different material than the hollow support portion.

[0090] The dental retractor 9 comprises two portions 25a-b rigidly linked together, 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 with and move the lower lip and / or the upper lip of the user respectively into the service position of the device according to which the dental retractor is introduced into the mouth of the user.

[0091] The dental retractor 9 is a rim that projects outward from the tubular part 11, radially outward, from the longitudinal end of the tubular part opposite the bottom wall 13.

[0092] The rim is annular in shape, deformed into a saddle. The contour of the rim, observed along the X axis, is homothetic to the contour of the spreader opening.

[0093] The rim can extend a distance e from between 3 mm and 6 mm from the hollow support portion. The distance e is measured, in a cross-section to the longitudinal axis, between the outermost radial end of the rim and the hollow support portion, along an axis T tangent to the rim and passing through the point of intersection between the hollow support portion and the rim.

[0094] The image acquisition device 5 can be fixed to the support 3. For example, as illustrated in Figures 1, 4 and 7, the support has a receptacle 27 which defines a housing 29 of complementary shape to the acquisition device and in which the image acquisition device is received.

[0095] The receptacle comprises a receptacle wall 31, for example of hemicylindrical shape, which extends transversely between the opposite inner faces of the tubular part and longitudinally from the bottom wall of the hollow support portion.

[0096] In the illustrated example, the receptacle is formed from the material along with the hollow support portion. Alternatively, it can be fixed onto the hollow support portion.

[0097] The image acquisition device comprises a housing 33 and two optical assemblies 34, each including a camera 35 and an LED lamp 37, which are entirely housed within the housing. This number of cameras and lamps is not limited. The image acquisition device 5 may further include a communication module housed within the casing for transmitting the images captured through the spacer opening 17 by the cameras 35 to a storage unit. For example, the communication module may include a connector for a data transfer cable, and the back wall 13 may have a recess 39 through its thickness for inserting the connector of such a cable and plugging it into the connector.

[0098] In the illustrated example, each camera 25 is equidistant from the dental retractor 9. Each camera is positioned at a distance D of less than 42 mm from the dental retractor. Furthermore, the length L of the hollow support portion 7, measured along the longitudinal axis, can be less than 8 cm. Thus, the imaging device is particularly compact, which facilitates its handling.

[0099] In order to take extraoral images of his dental arches, the user takes hold of the hollow support portion 7 to introduce the dental retractor 9 into his mouth and bring the lower support surfaces 27a and upper 27ben into contact with his lower and upper jaws respectively, so as to curl up the lower and upper lips respectively.

[0100] Extraoral shots and the acquisition of corresponding images can then be carried out.

[0101] Figures 8 and 9 illustrate a second embodiment of the image-capturing device according to the invention. This other embodiment differs from the first embodiment shown in Figures 1 to 7 in that it comprises two receptacles 27 shaped to each receive an image acquisition device. The receptacles may be formed from the same material as the hollow support portion or be fixed to the hollow support portion.

[0102] The receptacles are symmetrical to each other with respect to a longitudinal plane median P of the support which contains the longitudinal axis X.

[0103] The receptacles each define tubular housings with respective axes Yi and Y2 which are inclined with respect to the longitudinal axis X by the same angle 0.

[0104] The acquisition devices, not illustrated, may each include an optical assembly.

[0105] The optical assemblies can be arranged symmetrically with respect to the longitudinal median plane of the support, for example, so as to construct a 3D stereoscopic model representing the common scene seen by the cameras through the spreader aperture. The cameras of each optical assembly are, for example, aligned along axes Yi and Y2, respectively. The light sources of each optical assembly comprise, for example, LEDs distributed around the camera's periphery regularly around the respective axes Yi and Y2.

[0106] The example illustrated in [Fig. 10] differs from the example illustrated in [Fig. 1] in that it comprises two image acquisition devices 5 in contact with the bottom wall 13 of the hollow support portion 7 and arranged symmetrically with respect to each other with respect to a first median longitudinal plane PL. Each image acquisition device 5 comprises two optical assemblies 34 each comprising a camera 35 and an LED lamp 37.

[0107] The optical assemblies 34 are arranged symmetrically with respect to a second median longitudinal plane P2 of the device, orthogonal to the first median longitudinal plane. The viewing axes of the cameras may be parallel to each other, or form an angle between them, as in the second example illustrated in [Fig. 8], and for example intersect at a single point.

[0108] Figures 11 to 14 illustrate a fourth example of device 1 according to the invention, which differs from the devices illustrated in Figures 1 to 10 in particular in that the support 3 comprises a hollow support portion 7 and a graspable support portion 41 which extends the hollow support portion 7.

[0109] The support portion 7 further comprises ridges 43 which are carried by the outer wall 45 of the tubular part 11. The ridges 43 are arranged symmetrically with respect to a longitudinal median plane P of the hollow support portion 7. They are each longitudinally surmounted by a head 47 on which a dental retractor not shown, such as described for example in application WO 2022 / 008533, can be snapped or fitted by complementary shape.

[0110] The hollow support portion 7 has the shape of a tubular housing opening through a support opening 49 and includes a bottom wall 13, opposite the support opening 49. The bottom wall 13 separates the hollow support portion 7 from the graspable support portion 4L. An acquisition device 5 is disposed in contact with the bottom wall and includes an optical assembly equipped with a camera for viewing a scene through the support opening 49 and the retractor opening, not shown.

[0111] The hollow support portion 7 is disposed between the dental retractor and the graspable portion 41.

[0112] The graspable support portion 41 may have a general parallelepiped shape, the length, width, and height of which are chosen for easy grasping. However, any other suitable shape may be considered. The graspable support portion 41 extends longitudinally, opposite the dental retractor, from the base wall 13. It also projects laterally from the hollow support portion 7. The graspable support portion 41 may be hollow and include a cavity 51 accessible through an access opening 53 opposite the retractor opening.

[0113] The access opening 53 may be covered by a lid, not shown, to close off the cavity 51 in order to protect components that may be housed in the cavity, to conceal them from the user's view, and to facilitate handling of the device. An electronic board, not shown, for controlling and / or monitoring the image acquisition device may be housed in the cavity, as well as a battery to power the electronic board and the image acquisition device.

[0114] Furthermore, side windows 55 are provided in the side wall 57 of the graspable support portion 41, for example for the passage through the side wall into the cavity of a data transfer cable and / or electrical charging cable for the battery, or for providing a switch to turn the device on and / or off.

[0115] Obviously, the invention is not limited to the examples described by way of illustration and not limitation.

[0116] For example, in a variant of the device illustrated in Figures 11 and 14, the support may include a dental retractor being a rim coming from material with the tubular part 11, as illustrated in [Fig.1].

Claims

Claims

1. Device (1) for extraoral photography, comprising - a support (3) comprising a hollow support portion (7), - a dental retractor (9) carried by the hollow support portion, the dental retractor defining a retractor opening (17), the surface area covered by the retractor opening being greater than 2 cm2, - an image acquisition apparatus (5) for taking images through the retractor opening, the hollow support portion (7) delimiting a photography chamber (15), the image acquisition apparatus (5) being at least partially, preferably entirely, housed in the photography chamber, the support (3) further comprising a gripping support portion (41) which is mounted on the hollow support portion (7), the hollow support portion being removably fixed to the gripping support portion.

2. Device according to claim 1, the volume occupied by the image acquisition device being less than 40 cm3.

3. Device according to any one of claims 1 and 2, the image acquisition apparatus being fixed on the support, preferably on the hollow support portion, and comprising a camera (25) less than 15 cm, preferably less than 7 cm, from the dental retractor.

4. Device according to any one of the preceding claims, the camera (25) having a focal length of between 25 mm and 90 mm, preferably between 30 mm and 45 mm.

5. A device according to any preceding claim, the image acquisition apparatus being spaced less than 6 cm, preferably between 2.5 cm and 6 cm, from the dental retractor.

6. Device according to any one of the preceding claims, comprising a connection module for transferring the images acquired by the image acquisition device, preferably comprising a connection socket for a data transfer cable, for example a USB® cable, or such a data transfer cable, or being a remote data transfer module, for example implementing the Wifi® or Bluetooth® data transfer protocol.

7. Device according to any one of the preceding claims, the image acquisition apparatus comprising, or even consisting of, at least two cameras, preferably arranged along view axes different, and to acquire each of the different views of the same dental scene.

8. A device according to any preceding claim, the hollow support portion (7) extending longitudinally and the dental spacer (9) extending the hollow support portion.

9. Device according to the preceding claim, the dental retractor (9) being a rim, in particular annular or in the form of a part of a ring, extending radially outwards from one end of the hollow support portion (7).

10. A device according to any one of claims 8 and 9, the dental retractor being integral with the hollow support portion.

11. Device according to the preceding claim, the hollow support portion (7) being arranged between the dental retractor (9) and the grippable support portion (41).

12. A device according to any preceding claim, comprising a control module for controlling the acquisition of the images, preferably comprising a memory storing a computer program and a processor for executing the computer program, the computer program comprising instructions for guiding the user, for example by issuing a voice message, in order to position the device relative to the patient's teeth to a predetermined acquisition position and / or orientation.

Images