Distraction set including a palatal distractor and an activation tool

Abstract

The present invention relates to a distraction assembly (1), comprising: - a palatal distractor (3), including an activation rod (7) and a body (9) segmented into a first part (11) comprising a first magnetic assembly (13) consisting of at least one first permanent magnet (15), and a second part (12), the rotation of the activation rod (7) causing a relative displacement of the first part (11) and the second part (12) along a distraction axis X, - an activation tool (5) removably fixed to the first part (11), including a drive member (19) configured to rotate the activation rod (7), and a second magnetic assembly (23) consisting of at least one second magnet, preferably permanent (25), the fixed connection between the first part (11) and the activation tool (5) comprising a magnetic coupling of the first magnetic assembly (13) and the second magnetic assembly (23). Figure for the abstract: Figure 1

Description

Title of the invention: Distraction assembly comprising a palatal distractor and an activation tool

[0001] The invention relates to the field of palatal distractors. More specifically, the invention relates to a distraction assembly comprising a palatal distractor and an activation tool.

[0002] A palatal distractor is a medical device, which rests on the teeth of a subject and exerts a force on them in order to widen the palate of the subject. A palatal distractor is generally placed by an orthodontist so as to match the shape of the palate. The force to widen the palate is applied by modifying the width of the palatal distractor along a distraction axis. The progressiveness of the widening is achieved through frequent activation, for example daily.

[0003] The art is already known in the state of the art, in particular from the document US 2003 / 013061 A1, an orthodontic tool for adjusting the distraction force of an orthodontic distraction screw, in particular a palatal distractor. In this document, a palatal distractor comprises a body segmented into two parts and a threaded distraction rod provided with a receiving area for a hand-held adjustment tool. The adjustment tool comprises a handle and an end provided with a key, the key being intended to be inserted into the distraction rod in order to carry out activation, i.e. a rotation of the distraction rod allowing a relative displacement of the two parts along a distraction axis.

[0004] However, the relative positioning of the adjustment tool, also called an activation tool, and the palatal distractor is difficult, in particular because a user handling the adjustment tool does not have easy access to the palatal distractor. This access is difficult, whether visually or by contact, due to the limited accessibility of the mouth opening. Furthermore, the use of a key as an adjustment tool may hinder or injure a subject on whom the palatal distractor is mounted, in particular because such a key is relatively thin. Indeed, this activation is painful and difficult because it requires great precision in the gesture, in particular to insert the key. This gesture is difficult to perform on a subject such as a child, for example an agitated child, or more generally on a subject with a mouth opening problem.Furthermore, the key can be difficult for a user to operate, especially an anxious parent who may be afraid of hurting their child.

[0005] Thus, the invention aims in particular to provide a distraction assembly comprising a palatal distractor and an activation tool, making it possible to carry out activation of the palatal distractor via the activation tool in a simpler and safer way.

[0006] To this end, the invention relates to a distraction assembly, comprising:

[0007] - a palatal distractor, which comprises an activation rod and a segmented body in a first part and in a second part, the rotation of the activation rod causing a relative displacement of the first part and the second part along a distraction axis X,

[0008] - an activation tool, which comprises a drive member configured to drive the activation rod in rotation, the activation tool being removably attached to the first part,

[0009] the first part comprising a first magnetic assembly composed of at least one first permanent magnet,

[0010] the activation tool comprising a second magnetic assembly composed of at least one second magnet,

[0011] the fixed connection between the first part and the activation tool comprising a magnetic coupling of the first magnetic assembly and the second magnetic assembly.

[0012] By virtue of the first magnetic assembly and the second magnetic assembly, a fixed connection is achieved in a simple manner. Thanks to the reversibility of the connection provided with a magnetic coupling, once activation has been carried out during which a distraction or a bringing together of the first part and the second part is carried out, a user can easily separate the activation tool from the first part of the palatal distractor. The use of a driving member makes the use of the activation tool even simpler, since the user does not have to carry out the driving of the activation rod himself. Furthermore, such use improves safety during activation, since once the fixed connection is made between the first part of the palatal distractor and the activation tool, there is no risk of injury due to movement of the activation tool, the activation tool being fixed on the first part of the palatal distractor.

[0013] According to other optional characteristics of the distraction assembly, taken alone or in combination:

[0014] - The second magnetic assembly is composed of at least one second magnet permanent. Thus, the second magnetic assembly is made in a simple way.

[0015] - The or each first permanent magnet is magnetized in a direction opposite to that of the or one of the second permanent magnets. Thus, each pair of magnets, formed by a first permanent magnet and a second permanent magnet, is such that the first permanent magnet and the second permanent magnet attract each other due to their opposite magnetizations. The magnetic coupling is then improved.

[0016] - At least one, preferably each pair of magnets, formed by a first magnet permanent magnet and by a second permanent magnet, is such that the first permanent magnet and the second permanent magnet are identical. Thus, the design is simplified while optimizing the magnetic coupling.

[0017] - The activation rod is at least partially threaded, the thread of which is inserted in a tapping of the second part. Thus, the rotation of the activation rod causes a sliding along the distraction axis X of the second part relative to the first part, and this in a particularly simple manner.

[0018] - The distraction assembly comprises a drive mechanism, arranged on the activation tool and / or on the palatal distractor, interposed between an output shaft of an electric motor driving the drive member and the activation rod, a rotation of the output shaft causing a rotation of the activation rod via the drive mechanism.

[0019] - The drive mechanism comprises a first toothed wheel and a screw without end or a second gear wheel, the first gear wheel being fixed on the activation rod, the worm or the second gear wheel being arranged on the activation tool and being rotated by the electric drive motor, the first gear wheel being meshed with the worm or the second gear wheel. Thus, the drive mechanism is made in a simple manner and makes it possible to limit the forces exerted in the radial direction relative to the distraction axis X.

[0020] - The drive mechanism comprises a flexible drive shaft comprising a first end and a second end opposite the first end, the first end being kinematically connected to the activation rod, reversibly tiltable by at least an angle between 15° and 90°, preferably between 25° and 45°, relative to its position axially aligned with the second end, the second end being kinematically connected to the output shaft of the electric drive motor. The use of such a flexible drive shaft simplifies the design while facilitating the manipulation by a user of the activation tool, with regard to the position of the palatal distractor in the mouth of a subject.

[0021] - The activation tool includes a handle configured to be held by the hand of a user. This makes it easier to grip the activation tool.

[0022] - The at least one first permanent magnet is integrated in an envelope in biocompatible material, preferably according to ISO 10993-1:2018.

[0023] - The at least one first permanent magnet is integrated in an envelope in plastic material. The use of plastic material allows for a lightweight and inexpensive envelope. Preferably, the plastic envelope is made from epoxy resin.

[0024] - The at least one first permanent magnet is integrated into a titanium casing or stainless steel, preferably non-magnetic stainless steel. The use of titanium or stainless steel makes it possible to create a particularly resistant casing.

[0025] - The at least one first permanent magnet and the first part are integrated in the same material. Thus, the design and manufacture of the palatal distractor are simplified.

[0026] - The at least one second permanent magnet is integrated in an envelope in biocompatible material, preferably according to ISO 10993-1:2018.

[0027] - The at least one second permanent magnet is integrated in an envelope in plastic material. The use of plastic material allows for a lightweight and inexpensive envelope. Preferably, the plastic envelope is made from epoxy resin.

[0028] - The at least one second permanent magnet is integrated into a titanium casing or stainless steel, preferably non-magnetic stainless steel. The use of titanium or stainless steel makes it possible to create a particularly resistant casing.

[0029] - The drive member comprises an electric drive motor. Thus, the drive member is made in a simple manner. Preferably, the electric drive motor is a stepper electric motor. This makes it easier to control the electric drive motor.

[0030] - The activation tool includes a rechargeable battery powering the motor electric drive. This makes the activation tool easy to use, particularly since it does not require a specific connection. Furthermore, since the electrical risk is significantly reduced, the safety of such an activation tool is thus increased.

[0031] - The at least one first permanent magnet and the at least one second magnet permanent magnets are of the neodymium type, preferably based on Nd2Fei4B. Thus, these permanent magnets can be produced in a particularly compact manner.

[0032] - The activation tool comprises mechanical coupling means, which are removably coupled with the palatal distractor. Preferably, the mechanical coupling means comprise a hook, the hook being removably hooked onto the palatal distractor. The use of such mechanical coupling means, preferably such a hook, prevents inadvertent decoupling of the magnetic coupling, for example due to forces exerted during training. The combination of the at least one first and at least one second permanent magnets and the mechanical coupling means, preferably the hook, thus allows for more secure training. The fixed connection is thus improved while remaining removable.

[0033] - The activation tool comprises a support stop on the body, preferably at less on the first part. This makes it easier to position the activation tool on the palatal distractor.

[0034] - The first magnetic assembly comprises a single first permanent magnet and The second magnetic assembly has a single second permanent magnet. Thus, the design of the distraction assembly is simplified.

[0035] - The first permanent magnet and the second permanent magnet are of the same shape asymmetrical in section orthogonal to the axis between their poles, for example L-shaped. Thus, the positioning of the activation tool on the palatal distractor is facilitated, because the asymmetrical shape has a foolproofing function.

[0036] - The first magnetic assembly comprises a plurality of first magnets permanent magnets and the second magnetic assembly comprises a plurality of second permanent magnets, and wherein the fixed connection between the palatal distractor and the activation tool comprises a magnetic coupling of the first permanent magnets of the first magnetic assembly and the second permanent magnets of the second magnetic assembly. Thus, positioning of the activation tool on the palatal distractor is facilitated.

[0037] - The first magnetic assembly comprises three first permanent magnets and the second magnetic assembly includes three second permanent magnets. The use of three pairs of permanent magnets makes positioning easier while optimizing the size of the first magnetic assembly and the second magnetic assembly.

[0038] - At least two first permanent magnets of the first magnetic assembly are such that the axis between the poles of one of the first two permanent magnets is oblique to the axis between the poles of the other of the first two permanent magnets.

[0039] - At least two second permanent magnets of the second magnetic assembly are such that the axis between the poles of one of the two second permanent magnets is oblique to the axis between the poles of the other of the two second permanent magnets.

[0040] - The second magnetic assembly is slidably arranged in a groove of the tool activation. Thus, the magnetic coupling between the first magnetic assembly and the second magnetic assembly can be greatly reduced due to the sliding of the second magnetic assembly in the groove. It is then easier for a user to separate the activation tool from the palatal distractor, and the risk of the palatal distractor being detached from the subject on which the palatal distractor is mounted is reduced. Brief description of the figures

[0041] The invention will be better understood on reading the following description given solely by way of example and with reference to the appended drawings in which:

[0042] [Fig.l] is a schematic view of a distraction assembly according to a first embodiment, in which the activation tool is attached to the palatal distractor;

[0043] [Fig.2] is a schematic view of a distraction assembly according to the first mode embodiment, in which the activation tool is separate from the palatal distractor;

[0044] [Fig.3] is a schematic sectional view of a portion of a distraction assembly according to a second embodiment, in which the activation tool is attached to the palatal distractor;

[0045] [Fig.4] is a schematic sectional view of part of a distraction assembly according to the second embodiment, in which the activation tool is separate from the palatal distractor;

[0046] [Fig.5] is a perspective view of part of a distraction assembly according to the second embodiment, wherein the activation tool is separate from the palatal distractor;

[0047] [Fig.6] is a perspective view of a distraction assembly according to a third embodiment, wherein the activation tool is attached to the palatal distractor, and wherein the second magnetic assembly is in an activation position;

[0048] [Fig.7] is a perspective view of a distraction assembly according to the third embodiment, wherein the activation tool is attached to the palatal distractor, and wherein the second magnetic assembly is in a separation position.

[0049] In all the figures, the same references refer to the same elements.

[0050] In this detailed description, the following embodiments are examples. Although the description refers to one or more embodiments, this does not mean that the features apply only to a single embodiment. Single features of different embodiments may also be combined and / or interchanged to provide other embodiments.

[0051] [Fig.l] and [Fig.2] show a distraction assembly according to a first embodiment, designated by the general reference 1, according to different configurations.

[0052] The distraction assembly 1 comprises a palatal distractor 3 and an activation tool 5.

[0053] The palatal distractor 3 comprises an activation rod 7 and a body 9 segmented into a first part 11 and a second part 12. The activation rod 7, the first part 11 and the second part 12 are made of biocompatible material, preferably according to the ISO 10993-1:2018 standard. For example, the activation rod 7 is made of stainless steel, preferably non-magnetic, the first part 11 is made of plastic material, preferably based on epoxy resin, and / or stainless steel, preferably non-magnetic, and / or titanium, and the second part 12 is made of plastic material, preferably based on epoxy resin, and / or stainless steel, preferably non-magnetic. magnetic, and / or titanium. The rotation of the activation rod 7 causes a relative displacement of the first part 11 and the second part 12 along a distraction axis X. In this embodiment, the activation rod 7 is at least partially threaded, the thread of which is inserted into a tapping of the second part 12. Thus, the rotation of the activation rod 7 causes a sliding along the distraction axis X of the second part 12 relative to the first part 11. The first part 11 comprises a first magnetic assembly 13 composed of at least one first permanent magnet 15. The at least one first permanent magnet 15 is of the neodymium type, preferably based on Nd2Fei4B. The at least one first permanent magnet 15 is integrated in a casing 17 made of biocompatible material, preferably according to the ISO 10993-1:2018 standard.In this embodiment, the at least one first permanent magnet 15 is integrated into a casing 17 made of plastic material, preferably based on epoxy resin, or into a casing made of titanium or stainless steel, preferably made of non-magnetic stainless steel. For example, the at least one first permanent magnet 15 and the first part 11 are integrated into the same material. In the example illustrated in Figures 1 and 2, the first magnetic assembly 13 comprises a single first permanent magnet 15.

[0054] The activation tool 5 comprises a drive member 19, as well as a second magnetic assembly 23 composed of at least one second magnet, in this embodiment of at least one second permanent magnet 25. The at least one second permanent magnet 25 is of the neodymium type, preferably based on Nd2Fei4B. The at least one second permanent magnet 25 is integrated in a casing 27 made of biocompatible material, preferably according to the ISO 10993-1:2018 standard. In this embodiment, the at least one second permanent magnet 25 is integrated in a casing 27 made of plastic material, preferably based on epoxy resin, or in a casing made of titanium or stainless steel, preferably non-magnetic stainless steel. In the example illustrated in Figures 1 and 2, the second magnetic assembly 23 comprises a single first permanent magnet 25. The activation tool also comprises a handle 29 configured to be held by a user's hand.

[0055] The drive member 19 comprises an electric drive motor 31. In this embodiment, the electric drive motor 31 is a stepper electric motor. In order to power the electric drive motor 31, the activation tool 5 comprises a rechargeable battery 33 powering the electric drive motor 31, for example of the Lithium-Ion type.

[0056] The activation tool 5 is removably attached to the first part 11. Thus, as shown in [Fig.l], the activation tool 5 is attached to the first part 11. In this configuration, the fixed connection between the first part 11 and the activation tool 5 comprises a magnetic coupling of the first magnetic assembly 13 and the second magnetic assembly 13. More specifically, the first permanent magnet 15 is magnetized in a direction opposite to that of the second permanent magnet 25, such an orientation thus making it possible to achieve the magnetic coupling. Indeed, the pair of magnets formed by the first permanent magnet 15 and the second permanent magnet 25 is such that the first permanent magnet 15 and the second permanent magnet 25 attract each other due to their opposite magnetizations. The drive member 19 is configured to drive the activation rod 7 in rotation. Once the activation has been carried out, a user separates the activation tool 5 from the palatal distractor 3 by exerting a force greater than the force generated by the magnetic coupling. As shown in [Fig. 2], the activation tool 5 is then separated from the first part 11, and can be removed pending a new activation.

[0057] The distraction assembly 1 comprises a drive mechanism 35, arranged on the activation tool 5 and / or on the palatal distractor 3, interposed between an output shaft of the electric drive motor 31 of the drive member 19 and the activation rod 7. Thus, a rotation of the output shaft causes a rotation of the activation rod 7 via the drive mechanism 35. In the embodiment shown in [Fig.l] and in [Fig.2], the drive mechanism 35 comprises a first toothed wheel 41 and a second toothed wheel 42, the first toothed wheel 41 being fixed on the activation rod 7, the second toothed wheel 42 being arranged on the activation tool 5 and being rotated by the electric drive motor 31. As can be seen in [Fig.l], the first toothed wheel 41 is meshed with the second toothed wheel 42.

[0058] According to a variant not shown of the first embodiment, the first permanent magnet 15 and the second permanent magnet 25 are of the same asymmetrical shape in section orthogonal to the axis between their poles, for example L-shaped.

[0059] [Fig. 3], [Fig. 4] and [Fig. 5] show a distraction assembly according to a second embodiment, designated by the general reference 1'. The elements composing the distraction assembly 1' according to the second embodiment are similar to those composing the distraction assembly 1 according to the first embodiment, with the exception of the elements set out below.

[0060] This distraction assembly 1' according to the second embodiment is distinguished from the distraction assembly 1 according to the first embodiment mainly in that in the first part 11', the first magnetic assembly 13' comprises a plurality of first permanent magnets 15', and in the activation tool 5', the second magnetic assembly 23' comprises a plurality of second permanent magnets 25'. More precisely, in this second embodiment, the first magnetic assembly 13' comprises three first permanent magnets 15' and the second magnetic assembly 23' comprises three second permanent magnets 25'. Thus, the fixed connection between the palatal distractor 3' and the activation tool 5' comprises a magnetic coupling of the first permanent magnets 15' of the first magnetic assembly 13' and the second permanent magnets 25' of the second magnetic assembly 23'. More specifically, each first permanent magnet 15' is magnetized in a direction opposite to that of one of the second permanent magnets 25', such an orientation thus making it possible to achieve the magnetic coupling. Thus, each pair of magnets, formed by a first permanent magnet 15' and a second permanent magnet 25', is such that the first permanent magnet 15' and the second permanent magnet 25' attract each other due to their opposite magnetizations.Furthermore, at least one, preferably each pair of magnets, formed by a first permanent magnet 15' and by a second permanent magnet 25', is such that the first permanent magnet 15' and the second permanent magnet 25' are identical.

[0061] In this second embodiment, at least two first permanent magnets 15' of the first magnetic assembly 13' are such that the axis A1 between the poles of one of the two first permanent magnets 15' is oblique relative to the axis A2 between the poles of the other of the two first permanent magnets 15'. Similarly, at least two second permanent magnets 25' of the second magnetic assembly 23' are such that the axis A3 between the poles of one of the two second permanent magnets 25' is oblique relative to the axis A4 between the poles of the other of the two second permanent magnets 25'.

[0062] Furthermore, in this second embodiment, the activation tool 5' comprises mechanical coupling means, which are removably coupled with the palatal distractor 3'. Preferably, the mechanical coupling means comprise a hook 51', the hook 51' being removably hooked onto the palatal distractor 3', as can be seen in [Fig. 3], in [Fig. 4] and in [Fig. 5]. The use of such a hook 51' prevents involuntary decoupling of the magnetic coupling, the fixed connection is thus improved while remaining removable. The activation tool also comprises a stop 53' for bearing on the body 2', preferably at least on the first part 11'.

[0063] Furthermore, in this second embodiment, instead of a second gear wheel 42, the drive mechanism 35' comprises a worm screw 52'. Thus, in this second embodiment, the drive mechanism 35' comprises a first gear wheel 41 and a worm screw 52', the first gear wheel 41 being fixed on the activation rod 7', the worm screw 52' being arranged on the activation tool 5' and being rotated by the electric drive motor 31. As can be seen in [Fig. 3], the first gear wheel 41 is meshed with the worm screw 52'. Furthermore, the drive mechanism 35' comprises a drive shaft flexible 54' comprising a first end and a second end opposite the first end. The first end is kinematically connected to the activation rod 7'. By "kinematically connected", it is to be understood in particular that a rotation on itself of the first end of the flexible drive shaft 54' causes a rotation of the activation rod 7'. More precisely, the first end of the flexible drive shaft 54' is fixed in this example to the worm screw 52', as can be seen in [Fig. 3]. The first end is reversibly tiltable by at least an angle between 15° and 90°, preferably between 25° and 45° as can be seen in particular in [Fig. 4], relative to its position axially aligned with the second end. The second end is kinematically connected to the output shaft of the electric drive motor 31.By "kinematically connected", it is to be understood in particular that a rotation of the output shaft of the electric drive motor causes a rotation on itself of the second end of the flexible drive shaft 54'. In fact, a rotation on itself of the second end of the flexible drive shaft 54' causes a rotation on itself of the flexible drive shaft 54', and consequently a rotation on itself of the first end of the flexible drive shaft 54', and a rotation of the activation rod 7' via the worm screw 52' and the toothed wheel 4L.

[0064] [Fig.6] and [Fig.7] show a distraction assembly 1” according to a third embodiment. The elements composing the distraction assembly 1” according to the third embodiment are similar to those composing the distraction assembly 1 according to the first embodiment or to those composing the distraction assembly 1' according to the second embodiment, with the exception of the elements set out below.

[0065] In this embodiment, the second magnetic assembly 23” is slidably disposed in a groove 55” of the activation tool 5” between an activation position, shown in [Fig. 6], and a separation position, shown in [Fig. 7]. For example, the sliding of the second magnetic assembly is operable by a user's finger. When the activation tool 5” is attached to the palatal distractor 3”, the second magnetic assembly 23” is further from the first magnetic assembly 13” in the separation position than in the activation position. Thus, it is easier for a user to separate the activation tool 5” from the palatal distractor 3”. For example, the first magnetic assembly 13” comprises a single first permanent magnet 15” and the second magnetic assembly 23” comprises a single second permanent magnet 25”.

[0066] The invention is not limited to the embodiments presented and other embodiments will become clear to those skilled in the art.

[0067] It is in particular possible to produce the at least one second magnet in the form of an electromagnet. Thus, when the electromagnet is activated, the attachment of the activation tool to the palatal distractor is then possible, and when the electromagnet is deactivated, the separation of the activation tool and the palatal distractor is facilitated. However, such a design is more complex and generates more space compared to the use of permanent magnets.

[0068] It is also possible to replace the first toothed wheel 41 with a wheel, preferably silicone-based, in order to reduce the quantity of residue likely to stick to it, in particular food when the subject has eaten. List of references

[0069] 1, 1', 1”: disjunction set 3, 3', 3”: palatal distractor 5, 5', 5”: activation tool 7, 7': activation rod 9, 9', 9”: body 11, 11', 11”: first part 12, 12', 12”: second part 13, 13', 13”: first magnetic set

[0070] 15, 15', 15”: first permanent magnet 17: envelope 19: drive organ

[0071] 23, 23', 23”: second magnetic assembly

[0072] 25, 25', 25”: second permanent magnet 27: envelope

[0073] 29: sleeve 31: electric drive motor 33: rechargeable battery

[0074] 35, 35': drive mechanism 41: first cogwheel 42: second cogwheel

[0075] 51': hook 52': worm screw 53': goal 54': flexible drive shaft

[0076] 55”: throat

[0077] X: distraction axis Al, A2, A3, A4: axis between the poles

Claims

Claims

1. Distraction assembly (1, 1', 1”), comprising: - a palatal distractor (3, 3', 3”), which comprises an activation rod (7, 7') and a body (9, 9', 9”) segmented into a first part (11, 11', 11”) and a second part (12, 12', 12”), rotation of the activation rod (7, 7') causing relative movement of the first part (11, 11', 11”) and the second part (12, 12', 12”) along a distraction axis X, - an activation tool (5, 5', 5”), which comprises a drive member (19) configured to drive the activation rod (7, 7') in rotation, the activation tool (5, 5', 5”) being removably attached to the first part (11, 11', 11”), the first part (11, 11', 11”) comprising a first magnetic assembly (13, 13', 13”) composed of at least one first permanent magnet (15, 15', 15”), the activation tool (5, 5', 5”) comprising a second magnetic assembly (23, 23', 23”) composed of at least one second magnet,the fixed connection between the first part (11, 11', 11”) and the activation tool (5, 5', 5”) comprising a magnetic coupling of the first magnetic assembly (13, 13', 13”) and the second magnetic assembly (23, 23', 23”).,

2. Distraction assembly (1, 1', 1”) according to the preceding claim, wherein the second magnetic assembly (23, 23', 23”) is composed of at least one second permanent magnet (25, 25', 25”).

3. Distraction assembly (1, 1', 1") according to any one of the preceding claims, which comprises a drive mechanism (35, 35'), arranged on the activation tool (5, 5', 5") and / or on the palatal distractor (3, 3', 3"), interposed between an output shaft of an electric drive motor (31) of the drive member (19) and the activation rod (7, 7'), a rotation of the output shaft causing a rotation of the activation rod (7, 7') via the drive mechanism (35, 35').

4. A distraction assembly (1, 1', 1”) according to the preceding claim, wherein the drive mechanism (35, 35') comprises a first gear wheel (41) and a worm screw (52') or a second gear wheel (42), the first gear wheel (41) being fixed to the activation rod (7, 7'), the worm screw (52') or the second gear wheel (42) being arranged on the activation tool (5, 5', 5”) and being rotated by the electric drive motor (31), the first gear wheel (41) being meshed with the worm screw (52') or the second gear wheel (42).

5. A distraction assembly (1, 1', 1”) according to any preceding claim, wherein the at least one first permanent magnet (15, 15', 15”) is integrated into a casing (17) made of plastic material.

6. A distraction assembly (1', 1”) according to any preceding claim, wherein the activation tool (5', 5”) comprises a hook (51'), the hook (51') being removably hooked onto the palatal distractor (3', 3”).

7. Distraction assembly (1', 1”) according to any one of the preceding claims, wherein the activation tool (5', 5”) comprises a stop (53') for bearing on the body (9', 9”), preferably at least on the first part (11', 11”).

8. A distraction assembly (1') according to any preceding claim, wherein the first magnetic assembly (13') comprises a plurality of first permanent magnets (15') and the second magnetic assembly (23') comprises a plurality of second permanent magnets (25'), and wherein the fixed connection between the palatal distractor (3') and the activation tool (5') comprises a magnetic coupling of the first permanent magnets (15') of the first magnetic assembly (13') and the second permanent magnets (25') of the second magnetic assembly (23').

9. Distraction assembly (1') according to the preceding claim, wherein: - at least two first permanent magnets (15') of the first magnetic assembly (13') are such that the axis between the poles of one of the two first permanent magnets (15') is oblique to the axis between the poles of the other of the two first permanent magnets (15'), and - at least two second permanent magnets (25') of the second magnetic assembly (23') are such that the axis between the poles of one of the two second permanent magnets (25') is oblique to the axis between the poles of the other of the two second permanent magnets (25').

10. A distraction assembly (1”) according to any one of claims 1 to 7, wherein the second magnetic assembly (23”) is slidably disposed in a groove (55”) of the activation tool (5”).

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