Jaw displacement system for influencing mandibular growth

Abstract

A jaw displacement system for moving a mandible (5) relative to a maxilla (6), comprising at least one bone anchor (7), an elongated jaw displacement device (8), and a frame (9), wherein the jaw displacement device (8), when the frame (9) is fixed to a molar (10) and the bone anchor (7) is fixed to a bone of the mandible (5) on the vestibular side, enables pressure to be applied between the frame (9) and the bone anchor (7) to move the mandible (5) ventrally relative to the maxilla (6).

Description

[Technical Field]

[0001] The present invention relates to a jaw displacement system for moving the mandible relative to the maxilla. The system includes at least one bone anchor including a fixation plate for fixing the bone anchor to a bone of the mandible. The fixation plate is connected to a connecting element that leads to an attachment member. When the bone anchor is attached to the bone, the connecting element must protrude through the gums so that the attachment member is located in the oral cavity.

[0002] The jaw displacement system further includes an elongated jaw displacement device having two opposing ends, one of which can be attached to a mounting member, allowing pressure to be exerted between the ends of the jaw displacement device. Thus, the jaw displacement device is adapted to be attached to a mounting member in the oral cavity at one end.

[0003] The jaw displacement system according to the present invention is particularly suitable as a medical device for influencing the growth and occlusion of the mandible in patients with a Class II occlusion, also known as a distal occlusion. In such patients, the teeth of the upper jaw are positioned too far forward compared to the teeth in the lower jaw. This is often caused by underdevelopment of the lower jaw and / or excessive growth of the upper jaw, resulting in a convex facial profile. [Background technology]

[0004] Patients with Class II malocclusion typically have an underdeveloped lower jaw, which causes the lower dental arch to be positioned too far back relative to the maxillary dental arch. This increases the distance between the upper and lower incisors. This can lead to one or more of the following complications: - Palatal bite of the lower incisors, - Ectopic lower and upper incisors, - Functional problems such as bruxism and temporomandibular joint pathology, and - Disfiguring facial features due to underdeveloped jaws and convex soft tissue contours.

[0005] Additionally, a receding lower jaw relative to the upper jaw can also lead to sleep apnea.

[0006] Several treatments currently exist for patients with Class II malocclusion. In young patients, attempts are made to stimulate mandibular growth. Moving the mandible into a forward position over time can induce growth changes in the temporomandibular joint and jaw angle (gonial angle), resulting in a permanent forward displacement of the jaw. This forward displacement of the mandible can be achieved through the use of removable or bonded orthodontic appliances, also known as orthopedic appliances because they attempt to alter jaw growth. A drawback of using such appliances is that they rest on the teeth, causing undesired tooth movement. Forward movement of the lower incisors is particularly undesirable. When using such over-the-teeth appliances, the undesired tooth movement ultimately becomes significantly greater than the intended growth change of the jaw.

[0007] In patients with Class II malocclusion, if there is no sufficient stimulation of mandibular growth or if growth has stopped, the mandible can only be moved forward by performing jaw surgery, specifically osteotomy.

[0008] One of the orthopedic devices used today to correct Class II malocclusions is the so-called Herbst device. The Herbst device has two telescopic joints that extend along both sides of the dental arch. The telescopic joints are connected to a frame attached to the upper and lower teeth. This device therefore ensures that the lower teeth, and the lower jaw itself, are pushed forward relative to the upper jaw as soon as the patient closes their mouth. However, due to the dental fixtures in the Herbst device, this primarily moves the teeth and only to a limited extent alters the growth of the lower jaw. The lower premolars and incisors are now moved forward, and these lower incisors are also tilted forward. This further leads to occlusion problems, periodontal problems, and bone loss at the roots of the lower incisors.

[0009] For example, patent documents U.S. Patent Application Publication No. 2014 / 0272759 and U.S. Patent No. 4,462,800 describe such uses of the Herbst device.

[0010] The Herbst device's telescoping joint is typically attached between a hinge located on the upper first molar and a hinge located on the lower first premolar. If the longitudinal axis of the telescoping joint, and more specifically the direction of the applied force, is excessively tilted relative to the occlusal plane and extends above the temporomandibular joint, this will cause posterior rotation of the mandible. This increases facial height and moves the jaw backward.

[0011] To overcome these drawbacks, mini-implants are sometimes used as an alternative to dental anchors to transmit the pressure of the Herbst device directly to the jawbone. Such systems are described, for example, in U.S. Patent Application Publication No. 2006 / 0172251, International Publication No. 2009 / 085321, or International Publication No. 2010 / 037195. However, the use of these mini-implants requires that the mini-implants be attached to the jawbone far enough away from the tooth roots to avoid damage to the roots, resulting in the orientation of the Herbst device deviating too far from the occlusal plane. As previously mentioned, such an orientation of the Herbst device causes posterior rotation of the mandible and does not provide sufficient stimulation for forward jaw growth in the ventral direction. Additionally, mini-implants are not well suited to absorbing the relatively large forces associated with the use of the Herbst device, resulting in frequent failure.

[0012] Furthermore, such treatment often results in a so-called crossbite as a result of moving the mandible forward relative to the maxilla, so that the widest part of the mandibular arch is positioned opposite the narrower part of the maxillary arch, thereby causing a crossbite. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] U.S. Patent Application Publication No. 2014 / 0272759 [Patent Document 2] U.S. Patent No. 4,462,800 [Patent Document 3] U.S. Patent Application Publication No. 2006 / 0172251 [Patent Document 4] International Publication No. 2009 / 085321 [Patent Document 5] International Publication No. 2010 / 037195 Summary of the Invention [Problem to be solved by the invention]

[0014] The present invention aims to solve the above-mentioned drawbacks by proposing a jaw displacement system having a jaw displacement device that allows the mandible to be moved ventrally relative to the maxilla without exerting pressure directly on the mandibular teeth. This ensures that the orientation of the jaw displacement device, and in particular the direction in which it exerts pressure, is as close as possible to the orientation of the occlusal plane. Furthermore, the jaw displacement system also makes it possible to absorb relatively large forces, for example, even in young patients whose maxilla and / or mandible have not yet fully grown. [Means for solving the problem]

[0015] For this purpose, the jaw displacement system comprises a frame that allows rigidly connecting the molars of the same quadrant of the maxilla to one another, the frame comprising a connection element for one of the ends of the jaw displacement device, when the frame is fixed to the molars and the bone anchor is fixed vestibularly to the bone of the mandible, the jaw displacement system according to the invention allows connecting said end of the jaw displacement device to said mounting member and said connection element, respectively, in order to exert pressure between the bone anchor and the frame to move the mandible in a ventral direction relative to the maxilla.

[0016] The frame preferably forms a rigid whole.

[0017] Preferably, the connecting element is provided on the frame at a position distal to the first molar when the frame is attached to the molar.

[0018] According to an interesting embodiment of the jaw displacement system according to the invention, a frame is provided in each of the two quadrants of the upper jaw, these two frames possibly being rigidly connected to each other.

[0019] According to a preferred embodiment of the present invention, the jaw displacement system comprises a rod and a rod guide, the rod connected to one end of the jaw displacement device and the rod guide connected to the opposite end of the jaw displacement device, whereby the rod can be moved relative to the rod guide in the longitudinal direction of the rod guide.

[0020] According to a particularly interesting embodiment of the invention, the rod guide comprises a spring element which makes it possible to exert pressure along the longitudinal direction of the rod guide, so that the rod guide can be deformed in its longitudinal direction between a compressed state and an extended state.

[0021] In an interesting manner, the jaw displacement device is at least partially made of a superelastic material, such as, for example, a nickel-titanium alloy. More particularly, the rod is preferably made of a superelastic material.

[0022] Thus, the present invention is advantageously applied to influence the growth of the mandible in patients with Class II malocclusion before the mandible has fully grown.

[0023] Further details and advantages of the invention will become apparent from the following description of some particular embodiments of the jaw displacement system according to the invention. This description is given by way of example only and does not limit the scope of the protection claimed. The reference numbers used hereafter refer to the accompanying drawings. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a schematic side view of the mandible and temporomandibular joint showing the effect of treatment with a jaw displacement system according to the present invention; [Figure 2] 1 is a schematic side view of a mandible and a maxilla fitted with a jaw displacement system according to an interesting embodiment of the invention; [Figure 3] FIG. 3 is a schematic front view of the mandible and maxilla with the jaw displacement system from FIG. 2. [Figure 4] 1 is a schematic perspective view of a frame and bone anchor with a jaw displacement device of a jaw displacement system according to the present invention; [Figure 5] 1 is a schematic side view of an interesting embodiment of a jaw displacement device for use in a jaw displacement system according to the invention; [Figure 6] FIG. 6 is a schematic side view of a variation of the jaw displacement device of FIG. 5 additionally including a compression spring. [Figure 7] FIG. 10 is a schematic perspective view of an end piece of the jaw displacement device forming a first end. [Figure 8] FIG. 8 is a schematic front view of the end piece from FIG. [Figure 9] 1 is a schematic perspective view of a rod for a jaw displacement device according to the present invention; FIG. [Figure 10] FIG. 1 is a schematic perspective view of a rod guide for a jaw displacement device according to the present invention; [Figure 11] 1 is a schematic view of the palate of the upper jaw provided with a frame according to an advantageous embodiment of the jaw displacement system according to the invention; [Figure 12] 1 is a schematic view of the upper palate provided with a frame according to a preferred embodiment of the jaw displacement system according to the invention; [Figure 13] FIG. 3 is a schematic side view of the upper jaw with the frame and rod guide from Figure 2 in the rod guide mounting position. [Figure 14] FIG. 3 is a schematic side view of the maxilla with the frame and rod guide from FIG. 2 when the rod guide is hanging freely in the oral cavity. DETAILED DESCRIPTION OF THE INVENTION

[0025] The jaw displacement system according to the present invention allows for the forward movement of a patient's mandible. When treating a patient with the system according to the present invention, several very favorable changes are observed in the patient's jaw that do not occur simultaneously with existing systems. Indeed, existing systems are thought to primarily ensure the displacement of the mandibular teeth relative to the jaw. However, when the jaw displacement system according to the present invention is used, several significant changes are achieved in the mandibular and maxillary jaws. FIG. 1 shows, in solid lines, a schematic representation of the jaw shape before treatment with the jaw displacement system according to the present invention is initiated, and in dotted lines, a schematic representation of the jaw shape after completion of treatment.

[0026] Thus, by applying the jaw displacement system according to the invention, it is ensured that the mandible 5 is stretched in the ventral direction, as indicated by reference number 1. In addition, it is also observed that the shape of the mandible 5 has changed, as the gonial angle of the mandible 5 has increased, as indicated by reference number 2. Furthermore, in the maxilla 6, the shape and position of the glenoid cavity, also called the mandibular fossa, also appears to have been surprisingly altered. As indicated diagrammatically by reference number 3, this has been moved slightly downward and forward by the treatment performed. A further advantage obtained by applying the invention is the reverse inclination of the incisors of the mandible 5, as indicated by reference number 4.

[0027] Thus, by applying the present invention, it is possible to achieve a combination of these beneficial effects to correct, for example, a patient's Class II malocclusion, a result that has not yet been achieved using existing non-surgical treatment methods for Class II malocclusion.

[0028] 2, 3 and 4 show diagrammatically a first embodiment of a jaw displacement system according to the invention, which allows for ventral movement of the lower jaw 5 relative to the upper jaw 6.

[0029] To this end, the jaw displacement system includes at least a bone anchor 7 , a jaw displacement device 8 , and a frame 9 .

[0030] The bone anchor 7 has a fixation plate 10 that must be fitted into the bone of the mandible 5 in order to fasten the bone anchor 7 to the mandible 5. Thus, through drill holes 11 in the fixation plate 10, the bone anchor is firmly fixed to the bone of the mandible 5 using screws. The fixation plate 10 is fitted onto a connection element 12 that leads to an attachment member 13. Here, the fixation plate 10 must press against the bone of the jaw 5 and extend below the gums, and the connection element 12 must protrude through these gums so that the attachment member 13 extends into the oral cavity. The connection element 12 preferably has a circular cross-section to ensure a good fit between the gums and this connection element 12.

[0031] The jaw displacement device 8 has an elongated shape and therefore two opposing ends 14 and 15. The first end 14 is provided with a fastening member for directly fastening the jaw displacement device 8 to the mounting member 13 of the bone anchor 7. In the proposed embodiment, the mounting member 13 has a hook 16 for this purpose, and the fastening member is formed by an annular eye 17. As shown in the figure, when the bone anchor 7 is attached to the mandible 5, the opening 18 of the hook 16 preferably faces away from the occlusal surface and is located primarily on the ventral side of the hook 16. This makes it possible to attach the jaw displacement device 8 to the bone anchor 7 by sliding the annular eye 17 along the opening 18 from bottom to top on the hook 16, thus directly connecting them. The description "bottom to top" means that the eye 17 is moved from the mandible 5 toward the maxilla 6 in a direction extending approximately transverse to the plane defined by the dental arch of the mandible 5.

[0032] A frame 9 of the jaw displacement system is provided for rigidly connecting the molars of the same quadrant of the maxilla 6. Such a frame 9 is custom-made for each individual patient. To this end, an intraoral scan of at least the molars of the patient's maxilla is performed, and based on the data obtained from this scan, frames are then digitally designed and manufactured for both quadrants of the maxilla 6 by so-called rapid prototyping techniques, such as, for example, selective laser melting (SLM).

[0033] Naturally, it is also possible to manufacture such a frame 9 in a manner known per se, starting from a physical model of the upper jaw.

[0034] The frame 9 consists of a rigid structure that must be connected laterally to the maxillary molars 19. It is usually preferred that this structure rigidly connect the first premolar, second premolar, and first molar in the same quadrant of the maxilla 6. The second molars are usually not surrounded distally by the frame 9, as there is a risk that the distal frame will be enlarged by the gums during treatment.

[0035] However, in order to avoid differences in the height of the chewing surfaces of the first and second molars due to the forces exerted on the frame 9 by the jaw displacement device 8 during treatment, it may in some cases be interesting to provide an occlusal support 20 on the frame 9. This occlusal support 20 extends above the chewing surface of the second molar, but does not necessarily have to rest on it, so that the growth of this second molar is not hindered unless it comes into contact with the occlusal support 20.

[0036] The frame 9 has a fastening element for the second end 15 of the jaw displacement device 8. This fastening element therefore makes it possible to connect the second end 15 of the jaw displacement device 8 directly to the frame 9.

[0037] This fastening element of the frame 9 is formed by a ring 21 which cooperates with a corresponding hook 22 provided for this purpose at the second end 15 of the jaw displacement device 8. Thus, the jaw displacement device 8 is detachably connected to the frame 9 by attaching the hook 22 to the ring 21 by hooking it onto this ring 21.

[0038] Jaw displacement device 8 generally comprises a rod 25 and a rod guide 26. The first end 14 in this case forms part of rod 25, while the end of rod guide 26 forms the second end 15 of jaw displacement device 8 and is provided with hook 22. Rod 25 is movable longitudinally of rod guide 26. By this movement of rod 25 relative to rod guide 26, the length of jaw displacement device 8 can be changed.

[0039] In the illustrated embodiment of the rod guide 26, it is made hollow. More specifically, the rod guide 26 has a central cylindrical bore that is open on both sides, through which the rod 25 can be moved longitudinally. The rod 25 in this case preferably comprises a cylindrical bar 27 that can be guided through the rod guide 26 in a telescopic manner.

[0040] The rod 25 is provided with an end piece 28, for example as shown in Figures 7 and 8. This end piece 28 is partly cylindrical and includes the annular eye 17 on one side and has an axial bore 29 on the opposite side, in which the cylindrical bar 27 is clamped or fastened. As a result, this cylindrical bar 27 has a diameter slightly smaller than that of the end piece 28. As a result, this end piece 28 forms a stop or cushion for the rod guide 26 when it slides over the cylindrical bar 27 of the rod 25.

[0041] Thus, when the jaw displacement system is mounted in the patient's mouth on either side of the jaw by means of bone anchors 7, jaw displacement devices 8, and frame 9, as shown in Figure 3, this ensures that the mandible 5 is pushed forward relative to the maxilla 6 when the mouth is closed. More specifically, the dimensions of rod guide 26 and end piece 28 of rod 25 are selected so that rod guide 26 presses against end piece 28 when the mouth is closed. As a result, in this position, pressure is applied between bone anchor 7 and frame 9, which displaces mandible 5 ventrally relative to maxilla 6.

[0042] Furthermore, the length of the rod 25, and more particularly the cylindrical bar 27, is selected so that when the jaws 5 and 6 are moved to the normal open position of the mouth, the bar 27 always extends partially within the rod guide 26, thereby causing the jaw displacement device 8 to extend integrally between the frame 9 and the mounting member 13 of the bone anchor 7.

[0043] The rod 25 and rod guide 26 of the jaw displacement device 8 are inflexible and preferably substantially incompressible in their longitudinal direction. Therefore, when the jaw displacement device 8 is placed in a patient's mouth, pressure can be applied by the jaw displacement device 8 between the bone anchor 7 and the frame 9. Therefore, when the patient closes their mouth, the lower jaw is moved forward relative to the upper jaw as a result of the pressure applied by the jaw displacement device 8. The rod 25 and rod guide 26 can be made of, for example, titanium, a memory alloy, or a relatively rigid plastic. Therefore, it is important that the rod 25 and rod guide 26 are inflexible to allow the jaw displacement device 8 to apply pressure longitudinally between the bone anchor 7 and the frame 9. Typically, jaw displacement devices are not flexible, allowing pressure to be applied between their ends. A flexible material or object is defined as a material or object that does not allow pressure to be applied between their opposite ends, such as in the case of a rope, rubber band, paper strip, etc.

[0044] To remove or fit jaw displacement device 8 into the oral cavity, jaws 5 and 6 are opened wide. In this wide-open position of the mouth, the total length of rod 25 and rod guide 26 is less than the distance between mounting member 13 and ring 21 of frame 9.

[0045] 13 shows the mounted position of the rod guide 26. In this position, the longitudinal direction of the rod guide 26 is tilted upward and extends partially above the frame 9, while the hook 22 remains connected to the frame 9 by the ring 21. In this mounted position, the opening 30 of the hook 22 is also oriented toward the top of the frame 9, facing away from the chewing surfaces of the teeth of the upper jaw 6. Thus, to remove the rod guide 26 from the hook 22, it is sufficient to move the rod guide 26 downward from the mounted position. To attach the rod guide 26 to the ring 21 on the frame 9, the rod guide 26 undergoes the same movement, but in reverse.

[0046] Thus, to assemble the jaw displacement device 8, after the rod guide 26 is connected to the frame 9 and the rod 25 to the bone anchor 7 as previously described, the jaws 5 and 6 are opened wide and the bar 27 is inserted into the bore in the rod guide 26. When the jaws are closed again, the bar 27 slides through the rod guide 26 until it reaches the corresponding end piece 28, at which point the mandible 5 is forced forward.

[0047] FIG. 6 shows an alternative embodiment of the jaw displacement device 8 according to the invention. Here, a compression spring 33 is arranged around the cylindrical bar 27 between the end piece 28 of the rod 25 and the rod guide 26. In the proposed embodiment, this compression spring 33 is formed by a helical spring coaxial with the rod 25. The presence of this compression spring 33, on the one hand, ensures that the displacement of the rod guide 26 toward the end piece 28 is somewhat damped when the jaws 5 and 6 close. Thus, the forces exerted on the frame 9 and the bone anchor 7 when the jaws 5 and 6 close are also damped, and the bone anchor 7 is subjected to a less impulse load. On the other hand, the presence of the compression spring 33 allows the pressure exerted by the jaw displacement device 8 on the bone anchor 7, and thus on the mandible 5, to be adjusted depending on the selected compression spring 33.

[0048] To avoid any plastic deformation when manipulating jaw displacement device 8, or more specifically rod 25, jaw displacement device 8 is preferably made at least partially of a superelastic material, in particular, for example, a nickel-titanium alloy. Thus, jaw displacement device 8 automatically returns to its original shape after it has been intentionally or unintentionally deformed. Preferably, rod 25 or cylindrical bar 27 of this rod is made of such a superelastic metal. Superelastic materials often have a relatively high elasticity but are not flexible.

[0049] Furthermore, if it is preferred to manufacture the rods 25 or bars 27 from a superelastic material, the diameter of these parts can be chosen to be smaller than if a non-superelastic metal were used, and indeed in the latter case it must be ensured that the diameter of the parts is large enough to avoid plastic deformation, for example by folding or bending.

[0050] In order to prevent the jaw displacement device 8, and more particularly the hook 22 of the rod guide 26, from being inadvertently or unintentionally removed from the ring 21 on the frame 9, the ring 21 is oriented relative to the frame 9 so that the central axis 23 of the ring 21 has a maximum angle α of about 20°, preferably 15°, with respect to the perpendicular to the plane 24 of the dental arch of the upper jaw 6, as represented diagrammatically in Figure 13. Preferably, it is ensured that the central axis 23 is virtually parallel to this perpendicular.

[0051] When the rod 25 is unintentionally or accidentally removed from the rod guide 26, the rod guide 26 automatically assumes the position shown in Fig. 14 due to gravity or the anatomical shape of the oral cavity. Here, the rod guide 26 extends mainly below the chewing surface of the maxilla 6 or below the frame 9 and is oriented towards the mandible 5. This ensures that the opening 30 of the hook 22 also faces the mandible, so that the hook 22 cannot be removed from the ring 21. Indeed, to remove the hook 22, the rod guide 26 must be manually placed in the mounting position described above and depicted in Fig. 13.

[0052] 11 shows a variant embodiment of the frames 9 of the jaw displacement system according to the invention, where one frame 9 is placed on the molars of each quadrant of the maxilla 6, and these frames 6 are connected by a rigid connecting rod 31.

[0053] 12 shows a very interesting embodiment of the frames 9 of the jaw displacement system according to the invention. Here, frames 9 are provided on the molars in each quadrant of the maxilla 6. These frames 9 are rigidly connected opposite the palate by palate expansion modules 32. Such modules are known per se to specialists and are frequently used to widen the maxilla 6 of a patient.

[0054] In the jaw displacement system according to the invention, it is very interesting to provide such extension modules 32 between the frames 9 of the upper jaw 6. Indeed, when the lower jaw 5 is moved forward relative to the upper jaw 6, as a result of the stimulated growth and the change in shape of the lower jaw 5, the lower dental arch will gradually move forward relative to the upper dental arch, which may result in a gradual crossbite during the treatment of the patient.

[0055] By applying the palate expansion module 32 during treatment with the jaw displacement device 8, it is also possible to gradually adjust the width of the upper jaw 6 in accordance with the displacement of the lower jaw 5 during gradual forward displacement and growth of the lower jaw 5, thereby avoiding the occurrence of crossbite.

[0056] It is also important to note that the lower jaw 5 and the upper jaw 6 are subjected to lateral displacement relative to one another by the use of eyes 17 or rings 21 which cooperate with respective hooks 16 or 22 of the connections at the ends 14 and 15 of the jaw displacement device 8. This allows the jaws 5 and 6 to be moved comfortably relative to one another, for example during chewing movements, regardless of the presence of an intraoral jaw displacement system.

[0057] In certain cases, it may be interesting to provide fastening means on the lateral sides of the frame 9 in order to, for example, fix orthodontic wires and thus also carry out orthodontic treatment in conjunction with the displacement of the mandible 5. More particularly, it is therefore possible, for example, to orthodontally treat the incisors of the upper jaw in this way. Figures 2 and 4 show such a fastening means in the form of a cylinder 34 having a bore with a rectangular section for the orthodontic wire.

Claims

1. A jaw displacement system for moving a lower jaw (5) relative to an upper jaw (6), comprising: at least one bone anchor (7), comprising a fixation plate (10) provided for fixing said bone anchor (7) to the bone of said mandible (5), said fixation plate (10) being connected to a connection element (12) leading to an attachment member (13), said connection element (12) having to protrude through the gums when said bone anchor (7) is fixed to said bone so that said attachment member (13) is located in the oral cavity; an elongated jaw displacement device (8) having two opposite ends (14, 15), a first of said ends (14) having a fastening member (17) that allows said jaw displacement device (8) to be attached to said mounting member (13); A jaw displacement system comprising:

1. A jaw displacement system comprising: a frame (9) provided for rigidly connecting molar teeth (19) of the same quadrant of the maxilla (6); the frame (9) comprising a fastening element (21) for a second end (15) of the jaw displacement device (8), thereby connecting the ends (14, 15) of the jaw displacement device (8) to the mounting member (13) and the fastening element (21), respectively, in such a way that, when the frame (9) is fixed to the molar teeth (19) and when the bone anchor (7) is fixed to the bone of the mandible (5) on the vestibular side, pressure can be applied between the frame (9) and the bone anchor (7), in particular the mounting member (13), in order to move the mandible (5) ventrally with respect to the maxilla (6).

2. 2. The jaw displacement system of claim 1, wherein the jaw displacement device (8) is not flexible and allows pressure to be applied longitudinally between two ends (14, 15) of the jaw displacement device (8).

3. 3. A jaw displacement system according to claim 1 or 2, wherein the fastening element forms a ring (21) and cooperates with a corresponding hook (22) provided for cooperation on the second end (15) of the jaw displacement device (8).

4. 4. A jaw displacement system according to claim 3, wherein the ring (21) is oriented relative to the frame (9) to which it is connected such that the central axis (23) of the ring (21) has a maximum deviation of 20° from a perpendicular to a plane (24) defined by the dental arch of the upper jaw (6), the central axis (23) preferably being substantially parallel to the perpendicular.

5. 5. The jaw displacement system according to claim 1, wherein the jaw displacement device (8) comprises a rod (25) and a rod guide (26), the rod (25) being connected to one end (14) of the jaw displacement device (8) and the rod guide (26) being connected to an opposite end (15) of the jaw displacement device (8), and the rod (25) being movable relative to the rod guide (26) in the longitudinal direction of the rod guide (26).

6. 6. The jaw displacement system of claim 5, wherein the rod guide (26) is made hollow, with the first end being open to allow the rod (25) to be moved and longitudinally guided within the rod guide (26).

7. 7. A jaw displacement system according to claim 5 or 6, wherein the jaw displacement device (8) is at least partly made from a superelastic material, in particular a nickel-titanium alloy.

8. A jaw displacement system according to any one of claims 5 to 7, wherein the rod (25) is at least partly made from a superelastic material, in particular a nickel-titanium alloy.

9. 9. A jaw displacement system according to claim 5, wherein the rod (25) comprises an end piece (28) forming the first end (24) and a bar (27) connecting to the end piece (28).

10. 10. The jaw displacement system of claim 9, wherein the bar (27) is made from a superelastic material.

11. A jaw displacement system according to any one of claims 1 to 10, wherein the frame (9) forms a rigid whole.

12. 12. The jaw displacement system according to claim 1, wherein the fastening element (21) is provided on the frame (9) at a position distal to and opposite the first molar (19) when the frame (9) is fixed to the molar (19).

13. 12. The jaw displacement system according to claim 1, wherein the fastening element (21) is provided on the frame (9) at a position that is between the first molar and the second molar when the frame (9) is fixed to the molars (19).

14. 14. The jaw displacement system according to claim 1, wherein the frame (9) has an occlusal support (20) which must extend at least partially opposite the chewing surface of the second molar when the frame (9) is fixed to the molar.

15. 15. The jaw displacement system according to any one of claims 1 to 14, wherein the fastening element (21) extends to the frame (9) buccally opposite the molar (19) when the frame (9) is fixed to the molar (19).

16. 15. A jaw displacement system according to any one of claims 1 to 14, wherein a frame (9) is provided for each of both quadrants of the upper jaw (6), and both frames (6) are rigidly connected to each other.

17. 16. The jaw displacement system according to any one of claims 1 to 15, wherein a frame (9) is provided for each of both quadrants of the upper jaw (6), and the frames (9) are connected by a palate extension module (32) that extends opposite the palate.

18. 18. A jaw displacement system according to any one of claims 1 to 17, wherein the frame (9) is provided for attachment to the molars (19), the frame at least partially surrounding each of the molars (19).

19. 19. A jaw displacement system according to any one of the preceding claims, wherein the jaw displacement device (8) comprises a spring element (33) making it possible to apply pressure between the ends (14, 15).

20. 20. A jaw displacement system according to any one of claims 1 to 19 for influencing the growth of the mandible (5) of a patient with a Class II malocclusion before said mandible (5) is fully grown.

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