Extra-oral image taking device

Abstract

Disclosed is an extra-oral image taking device (1) comprising: - a support (3) having a hollow support portion (7), - a mouthpiece (9) borne by the hollow support portion, the mouthpiece defining a mouthpiece opening (17), the area of the surface covered by the mouthpiece opening being greater than 2 cm2, - an image acquisition apparatus (5) for taking images through the mouthpiece opening, the hollow support portion (7) delimiting an image taking chamber (15), the image acquisition apparatus (5) being at least partially, preferably entirely, accommodated in the image taking chamber.

Description

[0001] Description

[0002] Title: Extraoral photography device

[0003] The present invention relates to a device for taking pictures of dental arches.

[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 using a camera equipped with an image acquisition device and a dental retractor.

[0006] Examples of such imaging devices are described in EP 3 391 810 A1 and WO 2022 / 008533 A1, which carry a mobile phone equipped with a camera for taking images of dental arches.

[0007] However, a cell phone is bulky and can make it difficult to handle these devices once the dental retractor is inserted into the user's mouth.

[0008] There is therefore a constant need for a new device for taking extraoral views of dental arches, particularly one that is easy to handle.

[0009] The invention relates to a device for extraoral photography, comprising

[0010] - a support comprising a hollow support portion,

[0011] - a dental retractor carried by the hollow support portion, the dental retractor defining a retractor opening, and

[0012] - an image acquisition device for taking images through the retractor opening.

[0013] According to a first aspect of the invention, the area of ​​the surface covered by the spacer opening is greater than 2 cm 2 , and the hollow support portion delimits a shooting chamber, the image acquisition device being at least partially, preferably entirely, housed in the shooting chamber. The device according to the first aspect of the invention is thus easily manipulated. The acquisition device being arranged at least partially in the shooting chamber, it hinders little or no manipulation of the device during shooting.

[0014] According to a second aspect of the invention, the image acquisition device is preferably fixed to the support, preferably to the hollow support portion, and comprises a camera, preferably less than 15 cm, better still less than 7 cm, from the dental retractor.

[0015] As will become more clear in the remainder of the description, the device according to the second aspect of the invention is advantageously compact, resulting in particular from the short distance separating the image acquisition device from the dental retractor, which makes it easy to handle.

[0016] 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.

[0017] Furthermore, the device according to the invention, and in particular according to any one of its first and second aspects, may comprise one or more of the optional characteristics described below.

[0018] 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.

[0019] “Extraoral” images are acquired by means of the device according to the invention, which in a service configuration in which the dental retractor is introduced into the user's mouth, is such that the image acquisition apparatus is outside the user's oral cavity. An extraoral image is acquired from a position remote from the oral cavity.

[0020] The image acquisition device is preferably spaced less than 6 cm from the dental retractor. It is preferably spaced 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 photography, the risk of it hitting the user's face, for example the nose, is reduced.

[0021] The volume occupied by the image acquisition device is preferably less than 40 cm 3, preferably less than 20 cm 3 , or even less than 10 cm 3 .

[0022] The mass of the image acquisition device is preferably less than 50 g, preferably less than or equal to 30 g.

[0023] Preferably, the length of the hollow support portion, measured along the longitudinal axis, is less than 10 cm.

[0024] The image acquisition device may not have 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.

[0025] The image acquisition device comprises, or even consists of, at least one camera for taking images through the spacer opening.

[0026] The camera can have a focal length between 25 mm and 90 mm, preferably between 30 mm and 45 mm.

[0027] Preferably, the focal length of the camera is 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] According to one variant, the image acquisition device may comprise, or even consist of, at least two cameras. The cameras may be arranged along different view axes, and each to 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 device allows images to be taken 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 image capture device may comprise 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 comprise the image storage unit.

[0032] The connection module can be fixed to the support, in particular to the hollow support portion, for example glued to a wall of the support.

[0033] Alternatively, the image acquisition device may comprise the connection module. In particular, the image acquisition device may comprise 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.

[0034] The connection module may comprise a socket for connecting 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.

[0035] 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 include an opening, for example axial or transverse, through which the connection socket opens out of the support, in particular out of the hollow support portion.

[0036] The hollow support portion can extend longitudinally and the dental retractor can extend the hollow support portion.

[0037] The hollow support portion may be made of cardboard or, preferably, of a thermoplastic material. The device is shaped such that in the service configuration, the hollow support portion is at least partially, preferably entirely, outside the user's mouth.

[0038] The hollow support portion may be grippable. It may include reliefs and / or shaped hollows to ensure optimal handling of the device.

[0039] The hollow support portion may comprise a bottom wall, for example a solid one, longitudinally opposite the spacer opening. The image acquisition device may be in contact with the bottom wall and in particular fixed to the bottom wall. 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 operating configuration of the device. The hollow support portion may have a substantially cylindrical shape.

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

[0041] 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.

[0042] The grippable support portion may longitudinally extend the hollow support portion and project transversely therefrom.

[0043] Preferably, the hollow support portion is disposed between the dental retractor and the grippable support portion.

[0044] 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.

[0045] The grippable support portion may define a cavity and include a cover closing the cavity. The device may include an electronic card including 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 sealing gaskets.

[0046] Furthermore, the battery can be autonomous. It can be charged electrically by induction, or by 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 grippable support portion may be covered at least in part by a flexible material facilitating its grip, for example a thermoplastic elastomer called "TPE", in particular a thermoplastic rubber called "TPR", such as styrene-butadiene-styrene, a thermoplastic polyurethane called "TPU". The dental retractor is preferably shaped to move, and preferably to curl, upwards and downwards respectively the upper and lower lips of the user, in a service configuration of the device according to which the dental retractor is introduced into the mouth of the user of the device, so as to maximize the dental surface visible by the image acquisition device. By "upwards" and "downwards" is meant the directions along a vertical axis when the user of the 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.

[0048] The dental retractor may be 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, and for example transversely to said portion. By "radially outwards" is meant that the tubular portion extends away from the longitudinal axis of the device in a plane transverse to this 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.

[0049] Furthermore, the dental retractor may be made of the same material as the support, and in particular with the grippable support portion. In other words, the dental retractor and the grippable support portion may be obtained jointly during the same manufacturing operation. The grippable support portion and the dental retractor may be obtained by molding and / or by additive manufacturing.

[0050] According to one variant, the dental retractor can be mounted on the hollow support portion. It can be fixed on the hollow support portion. The dental retractor can be rigidly fixed on the hollow support portion. For example, it is snapped, screwed or glued onto the gripping part. Alternatively, the dental retractor can be removably mounted on the hollow support portion, for example by magnetic coupling or by means of a hook-and-loop strip, or by form-fitting between the hollow support portion and the dental retractor. Advantageously, it is possible to mount different retractors of various sizes on the gripping support portion and thus to choose the dental retractor most suited to the morphology of the mouth of each user.

[0051] Preferably, the surface covered by the spacer opening has an area 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.

[0052] The device may include a mirror attached to the support such that the image acquisition apparatus 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 service configuration, the image acquisition apparatus thus sees a composite image comprising a direct image of the teeth viewed directly through the retractor opening and a reflected image of the teeth returned by the mirror.

[0053] Furthermore, the device may comprise a light source arranged to illuminate through the spacer opening.

[0054] The light source may include at least one lamp, in particular one with light-emitting diodes, and / or a flash.

[0055] The light source is preferably placed in the camera.

[0056] The 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.

[0057] In particular, the 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. In order to determine the color and / or translucency of the user's teeth, the device may comprise a colorimetric target and / or a translucency target respectively, fixed to the support, the image acquisition device seeing said target(s).

[0058] The device may include a control module to control the acquisition of images.

[0059] 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.

[0060] The actuator is for example a push button. It can be carried by the support.

[0061] The control module may comprise 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, and optionally, specifying to the user the number of images to be acquired.

[0062] The control module can be housed in the camera chamber.

[0063] Alternatively, the camera device may communicate, for example wirelessly or via a cable, with a control device, for example a mobile phone or a personal computer, comprising a control module as described above.

[0064] Furthermore, the imaging device may further comprise one or more additional cameras intended, in at least one configuration of the device, to be 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, 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.

[0065] Other characteristics and advantages of the invention will become apparent upon reading the detailed description which follows and the attached drawing in which:

[0066] [Fig. 1] and [Fig. 2] are perspective views according to different observation points and observation axes of a first example of an extraoral view device according to the invention,

[0067] [Fig. 3] is a view along the longitudinal axis of the device illustrated in Figure 1, [Fig. 4] is a sectional view along the plane (A- A) shown in Figure 2, [Fig. 5] and [Fig. 6] are a side view, along axes normal to the longitudinal axis, of the device,

[0068] [Fig. 7] is a sectional view along the plane (BB) shown in Figure 5,

[0069] [Fig. 8] is a sectional view along a longitudinal median plane of a second exemplary embodiment of the support of the device according to the invention,

[0070] [Fig. 9] is a view along the longitudinal axis and through the spacer opening of the bracket illustrated in Fig. 8,

[0071] [Fig. 10] is a perspective view of a third example of an extraoral viewing device according to the invention,

[0072] [Fig. 11] and [Fig. 12] are perspective views from different observation points and observation axes of a fourth example of an extraoral view device according to the invention, and

[0073] [Fig. 13] and [Fig. 14] are side and top views of the fourth example.

[0074] A first example of a device 1 for extraoral photography according to the invention is illustrated in Figures 1 to 7.

[0075] The device comprises a support 3 and an image acquisition device 5.

[0076] The support 3 comprises a hollow support portion 7. The device further comprises a dental retractor 9.

[0077] The hollow support portion 7 has a generally 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.

[0078] 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 grippable support portion 7 may be free of such a bottom wall.

[0079] At least a portion of the tubular part 11, or even the entire tubular part as illustrated, preferably extends parallel to the longitudinal axis X, to facilitate the holding and handling of the hollow support portion, which is thus also grippable.

[0080] The tubular part 11 has at least one transverse section S to the longitudinal axis X having a substantially oblong general shape, delimited by the dotted line outline in Figure 3. Such a shape of the hollow support portion facilitates gripping of the support and also corresponds substantially to the shape of the outline 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.

[0081] The tubular part 11 opens through another end longitudinally opposite the bottom wall, into a spacer opening 17.

[0082] 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 and as illustrated in Figures 5 and 6, 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.

[0083] The shape of the retractor opening is preferably adapted to the general shape of the user's dental arches.

[0084] Preferably, when viewed along the longitudinal axis, the maximum width l max of the spacer opening is between 60 mm and 70 mm and the minimum width 1min of the spacer opening is between 28 mm and 40 mm. The "maximum width" and "minimum width" are respectively the diameter of the smallest circle circumscribed around the contour of the spacer opening and the diameter of the large small circle inscribed in the contour of the spacer opening 17. Preferably, when observed along an axis perpendicular to the longitudinal axis, the height H of the contour of the spacer opening, measured along the longitudinal axis, is between 8 mm and 14 mm.

[0085] 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 can be envisaged, the dental retractor being, for example, made of a different material than the hollow support portion.

[0086] 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.

[0087] 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.

[0088] The rim is annular in shape, deformed into a horse saddle. The contour of the rim, observed along the X axis, is homothetic to the contour of the spreader opening.

[0089] The rim may extend a distance e of between 3 mm and 6 mm from the hollow support portion. The distance e is measured, in a section transverse to the longitudinal axis, between the most radially outer end of the bead 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.

[0090] The image acquisition apparatus 5 may be attached to the support 3. For example, as illustrated in FIGS. 1, 4 and 7, the support comprises a receptacle 27 which defines a housing 29 of complementary shape to the acquisition apparatus and in which the image acquisition apparatus is received.

[0091] 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.

[0092] In the example illustrated, the receptacle is integral with the hollow support portion. Alternatively, it may be fixed to the hollow support portion. 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. The image acquisition apparatus 5 may further comprise a communication module received in the housing for transmitting the images taken through the spacer opening 17 by the cameras 35 to a storage unit. For example, the communication module may comprise a connection socket for a data transfer cable, and the bottom wall 13 may comprise a recess 39 passing through its thickness to insert the connection plug of such a cable and plug it into the connection socket.

[0093] In the illustrated example, each camera 25 is equidistant from the dental retractor 9. The cameras are each arranged at a distance D less than 42 mm from the dental retractor. Furthermore, the length L of the hollow support portion 7, measured along the longitudinal axis, may be less than 8 cm. Thus, the camera device is particularly compact, which makes it easier to grip.

[0094] 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 27a and upper 27b bearing surfaces into contact with his lower and upper jaws respectively, so as to curl the lower and upper lips respectively.

[0095] Extraoral shots and acquisition of the corresponding images can then be carried out.

[0096] Figures 8 and 9 illustrate a second example of embodiment of the shooting device according to the invention. This other example differs from the first example illustrated in Figures 1 to 7 in that it comprises two receptacles 27 shaped to each receive an image acquisition device. The receptacles can be made of the same material as the hollow support portion or be fixed to the hollow support portion.

[0097] The receptacles are symmetrical to each other with respect to a median longitudinal plane P of the support which contains the longitudinal axis X.

[0098] The receptacles each define tubular housings of respective axes Yi and Y2 which are inclined relative to the longitudinal axis X by the same angle 9.

[0099] The acquisition devices, not shown, may each comprise an optical assembly. The optical assemblies may 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 spacer opening. The cameras of each optical assembly are for example of axis Yi and Y2 respectively. The light sources of each optical assembly comprise for example LEDs distributed around the camera regularly around the respective axes Y1 and Y2.

[0100] The example illustrated in Figure 10 differs from the example illustrated in Figure 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.

[0101] 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 view 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 the same point.

[0102] 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 grippable support portion 41 which extends the hollow support portion 7.

[0103] The support portion 7 further comprises beads 43 which are carried by the outer wall 45 of the tubular part 11. The beads 43 are arranged symmetrically with respect to a longitudinal median plane P of the hollow support portion 7. They are each surmounted longitudinally by a head 47 on which a dental retractor not shown, as described for example in application WO 2022 / 008533, can be snapped or fitted by form-fitting.

[0104] The hollow support portion 7 has the shape of a tubular housing opening through a support opening 49 and comprises a bottom wall 13, opposite the support opening 49. The bottom wall 13 separates the hollow support portion 7 from the grippable support portion 4L. An acquisition device 5 is arranged in contact with the bottom wall and comprises an optical assembly provided with a camera for viewing a scene through the support opening 49 and the spacer opening, not shown.

[0105] The hollow support portion 7 is arranged between the dental retractor and the gripping portion 41.

[0106] The grippable support portion 41 may have a generally parallelepiped shape, the length, width and height of which are chosen for easy gripping. Any other suitable shape may, however, be envisaged. The grippable support portion 41 extends longitudinally, opposite the dental retractor, from the bottom wall 13. It also projects laterally from the hollow support portion 7. The grippable support portion 41 may be hollow and include a cavity 51 accessible via an access opening 53 opposite the retractor opening.

[0107] The access opening 53 may be topped with a cover, not shown, to close the cavity 51 in order to protect organs that may be housed in the cavity, to hide them from the user's view, and to facilitate gripping of the device. An electronic card, not shown, for controlling and / or monitoring the image acquisition device may be housed in the cavity, as well as a battery for electrically powering the electronic card and the image acquisition device.

[0108] Furthermore, side windows 55 are provided in the side wall 57 of the grippable support portion 41, for example for the passage through the side wall into the cavity of a data transfer cable and / or electric recharging of the battery, or for providing a switch for turning the device on and / or off.

[0109] Obviously, the invention is not limited to the examples described for illustrative and non-limiting purposes.

[0110] For example, in a variant of the device illustrated in Figures 11 and 14, the support may comprise a dental retractor being a rim integral with the tubular part 11, as illustrated in Figure 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 cm 2 , - an image acquisition apparatus (5) for taking images through the spacer opening, the hollow support portion (7) delimiting a camera chamber (15), the image acquisition apparatus (5) being at least partially, preferably entirely, housed in the camera chamber, the support (3) further comprising a grippable support portion (41) which is mounted on the hollow support portion (7), the hollow support portion being removably fixed to the grippable support portion.

2. Device according to claim 1, the volume occupied by the image acquisition device being less than 40 cm 3 .

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 of between 30 mm and 45 mm.

5. Device according to any one of the preceding claims, 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 different view axes, and each for acquiring different views of the same dental scene.

8. Device according to any one of the preceding claims, 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 spacer (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. Device according to any one of claims 8 and 9, the dental retractor being integral with the hollow support portion.

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

12. Device according to any one of the preceding claims, 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 the emission of a voice message, in order to position the device relative to the patient's teeth to a predetermined acquisition position and / or orientation.

13. Device according to any one of the preceding claims, the grippable support portion (41) defining a cavity (51) and comprising a cover closing the cavity.

14. Device according to any one of the preceding claims, comprising an electronic card comprising a printed circuit and / or a battery controlling and / or electrically powering the image acquisition device, 15. Device according to claims 13 and 14, the electronic card and / or the battery being housed in the cavity (51).

16. Device according to any one of claims 13 to 15, the cavity (51) being made watertight, in particular by means of one or more sealing joints.

Images