Coupling system for orthodontic or orthopaedic components

Abstract

Orthodontic or orthopaedic connection system comprising: - a fastening stalk (1) with a first end (2) fixed to a first component (3), - a connection aperture (12) that is part of a second component (11), and - an elastic ring-shaped locking member (8) wherein the external diameter (D8) is larger than the diameter of said connection aperture (12), wherein the fastening stalk (1) has a spindle element (5) connecting to said first end (2), whose diameter is smaller than the diameter of said connection aperture (12) and wherein a second end (4) of the fastening stalk (1) has a stalk head (6) whose diameter (D6) is larger than the internal diameter (d8) of the locking member (8) and smaller than the diameter of said connection aperture (12), whereas a fixing shaft (7) having a diameter (d7) which is smaller than the diameter (D6) of the stalk head (6) extends between the stalk head (6) and said spindle element (5).

Description

[0001] COUPLING SYSTEM FOR ORTHODONTIC OR ORTHOPAEDIC COMPONENTS

[0002] The invention relates to an orthodontic or orthopaedic appliance with a connection system for detachably connecting two components of this appliance. More specifically, the invention relates to a connection system that allows a movable component to be connected to an anchor element such as, for example, a bone anchor or a frame, the frame being provided to fit neatly onto teeth of an upper or lower jaw.

[0003] Such a connection system is used for various orthodontic or orthopaedic applications in the mouth, but it is particularly relevant for applications where a connection with a high degree of rotational freedom between two components must be realised. This is the case, for example, when using Herbst appliances and jaw displacers derived from the latter, which allow a lower jaw to be moved relative to an upper jaw.

[0004] In such applications, the jaw displacer, in particular the Herbst appliance, ensures that the lower jaw is displaced in an anterior direction relative to the upper jaw. In addition, it must be ensured that the jaw displacer also allows other movements of the jaws relative to each other, such as, for example, lateral displacements to allow chewing movements while eating and vertical movements to open or close the mouth. Consequently, it is important that the connection between the jaw displacer and an anchor element fixed to the jaw not only ensures that the lower jaw is moved forward relative to the upper jaw, but also allows a rotation in a vertical or horizontal direction of the jaw displacer around this connection.

[0005] Furthermore, during a patient's treatment, it is generally necessary to detach and possibly remove the jaw displacer from the mouth at regular intervals to adjust it depending on the treatment's progress. To this end, it is therefore necessary that the connection system enables the treating physician to easily detach the jaw displacer from the anchor element to which it is attached with the connection system and subsequently reattach it if required. In addition, this connection system must be designed in such a way that the jaw displacer is not inadvertently detached from the anchor element.

[0006] According to the current state of the art, various connection systems are used. For example, in documents EP 2198802, US 6241517, US 6832911, US 2006 / 0172251, US 2006 / 0234180, WO 2010 / 037195 and WO 2018 / 136407, the use of small screws to connect the jaw displacer to an anchor element is described. Attaching or detaching such small screws in the oral cavity with an instrument provided for this purpose is very inconvenient for the physician due to the limited space and difficult accessibility in the oral cavity.

[0007] As an alternative to using a screw connection, a ball joint is often provided. However, these are relatively complex systems that often require many different small parts or for which a relatively complex custom design of the jaw displacer is required. A connection system with a ball joint is described, for example, in documents DE 4114285, EP 0774934, FR 2935261, US 5378147, US 5562445, US 5620321 and US 2007 / 0190477. The system described in document US 5378147, for example, is disadvantageous in that it is easily inadvertently dislodged when moving the jaws relative to each other, for example while chewing food.

[0008] Other connection systems use hooks, for example, as in US 2002 / 164555 and US 2002 / 0164555. In addition, there are some systems in which the jaw displacer has a ring at the far end that must be slid over a pin as described, for example, in CN 209661829U, EP 0419626, FR 2952294, US 4583944 or US 2014 / 272758. The latter systems can easily become unintentionally detached or they require the use of separate small, hard- to-handle parts.

[0009] The invention aims to remedy the above disadvantages by proposing a technically very simple and easy-to-produce connection system that can be easily assembled or disassembled very quickly by a physician. This connection system also allows great freedom of rotation to a component, such as in a jaw displacer, which is fitted with the latter without it becoming unintentionally detached.

[0010] To this end, the orthodontic or orthopaedic appliance according to the invention has a connection system for detachably connecting two components of the appliance, this connection system being provided with:

[0011] - a fastening stalk with a first end that is to be firmly connected to a first component of said components,

[0012] - a connection aperture with a diameter forming part of a second component of said components, and

[0013] - an elastic annular locking member with an internal diameter and an external diameter, the external diameter being greater than the diameter of said connection aperture.

[0014] According to the invention, the fastening stalk has a spindle element connecting to said first end. The diameter of the fastening stalk is smaller than the diameter of the connection aperture. A second end of the fastening stalk, opposite said first end, has a stalk head whose diameter is larger than the internal diameter of the locking member and smaller than the diameter of said connection aperture. A fixing shaft having a diameter smaller than the diameter of the stalk head hereby extends between the stalk head and said spindle element.

[0015] According to a simplified embodiment of the fastening stalk, the diameter of the fixing shaft corresponds to that of the spindle element and the spindle element forms part of the fixing shaft.

[0016] In a preferred embodiment of the appliance according to the invention, said two components form a jaw displacer and an anchor element respectively, the anchor element being provided to be firmly fixed relative to an upper or lower jaw.

[0017] According to an interesting embodiment of the appliance according to the invention, said first component forms the anchor element and preferably comprises a bone anchor or a frame, wherein the frame is provided to fit neatly onto teeth of an upper or lower jaw.

[0018] In an advantageous embodiment of the appliance according to the invention, said second component forms a jaw displacer, wherein one end of this jaw displacer is provided with said connection aperture.

[0019] The jaw displacer includes, for example, a rod and a rod guide, wherein the rod connects to a first end of the jaw displacer and the rod guide connects to a second end of the jaw displacer opposite to said first end. The rod is movable in this case along the longitudinal direction of the rod guide relative to the latter.

[0020] According to a very interesting embodiment of the appliance according to the invention, said locking member is formed by an elastic ring made of an elastomer or rubber. Alternatively, the ring can be formed by, for example, a circlip or a Seeger ring.

[0021] Preferably, the locking member forms a ring with a rectangular crosssection. When the locking member is made of elastomer or rubber, it normally forms a closed ring.

[0022] In certain embodiments of the appliance according to the invention, the stalk head has a lateral recess leading to the surface of the fastening stalk and extending at least to the fixing shaft, for example to the spindle element.

[0023] Other particularities and advantages of the invention will become apparent from the following description of some specific embodiments of the appliance according to the invention. This description is given as an example only and does not limit the scope of the claimed protection; the reference figures used hereinafter refer to the figures added thereto.

[0024] Figure 1 is a schematic front view of a fastening stalk according to an interesting embodiment of the invention.

[0025] Figure 2 is a schematic side view of the fastening stalk from Figure 1.

[0026] Figure 3 is a schematic top view of the fastening stalk from Figure 1.

[0027] Figure 4 is a schematic side view of a locking member formed by an elastic ring according to the invention.

[0028] Figure 5 is a schematic top view of the ring from Figure 4.

[0029] Figure 6 is a schematic front view of the fastening stalk from Figure 1 onto which a jaw displacer is attached with a locking member.

[0030] Figure 7 is a schematic front view of a fastening stalk according to another alternative embodiment of the appliance according to the invention.

[0031] Figure 8 is a schematic front view of the fastening stalk from Figure 7 onto which a jaw displacer is attached with a locking member.

[0032] Figure 9 is a schematic view of a dental instrument that can be used to remove the locking member from the fastening stalk.

[0033] Figure 10 is a schematic bottom view of an upper jaw provided with a frame having two fastening stalks according to the invention.

[0034] Figure 11 is a schematic side view of the upper jaw with the frame from

[0035] Figure 10 together with a lower jaw on which a bone anchor is placed and a jaw displacer.

[0036] Figure 12 is a schematic side view of an example of a jaw displacer according to the invention.

[0037] Figure 13 is a schematic side view of the rod guide of the jaw displacer from Figure 12.

[0038] Figure 14 is a schematic side view of the rod of the jaw displacer from

[0039] Figure 12.

[0040] Figure 15 is a variant embodiment of a jaw displacer, where it includes a helicoidal spring.

[0041] Figure 16 is a schematic side view of an upper jaw and a lower jaw provided with the appliance according to the invention.

[0042] Figure 17 is a schematic view of a bone anchor provided with a fastening stalk according to the invention. In the different figures, the same reference numerals refer to the same or analogous elements.

[0043] The invention generally relates to a connection system that is commonly used in orthodontic or orthopaedic treatments to connect two different components. This connection system allows the components to rotate relative to each other around a rotation axis on the one hand, and to also undergo a certain rotational displacement in a direction transverse to said rotation axis on the other hand. This connection system is therefore very suitable for attaching a jaw displacer, such as for example a Herbst appliance, to an anchor element, such as a bone anchor or a frame connected to the teeth. In addition, this connection system makes it possible to easily detach and reconnect the jaw displacer and the anchor element. This is particularly useful when, for example, the length of the jaw displacer needs to be adjusted as a function of the treatment's progress.

[0044] According to a preferred embodiment of the invention, the connection system for connecting two components comprises a fastening stalk 1 as shown in Figures 1 to 3. This fastening stalk 1 has a first end 2 connected to a first component 3. Adjacent to the first end 2, the fastening stalk 1 has a spindle element 5. Opposite the first end 2 and the first component 3, the fastening stalk 1 has a second end 4 onto which a stalk head 6 of this fastening stalk 1 connects. A fixing shaft 7 is provided between the stalk head 6 and the spindle element 5. The diameter d7of this fixing shaft 7 is smaller in this case than the maximum diameter Dg of the stalk head 6.

[0045] Further, the connection system comprises an annular locking member 8. Figures 4 and 5 show an interesting embodiment of such a locking member according to the invention. This locking member 8 is formed by a closed elastic ring 9 having an internal diameter dg. Here, the maximum diameter Dg of the stalk head 6 is larger than this internal diameter dg of the ring 9 or, in general, of the locking member 8.

[0046] In general, a locking member 8 forming a closed elastic ring 9 is preferably made of an elastomer or of rubber.

[0047] However, in an alternative embodiment, the locking member 8 may also be formed by an open ring. Such an open ring can be made of an elastic material such as plastic or metal. An example of an open ring is a so-called circlip or Seeger ring. Alternatively, the locking member 8 may form an elastic open ring that can be detachably attached around the fixing shaft 7.

[0048] A second component that can be connected to the first component 3 by means of the connection system is provided with a connection aperture 12. Figure 6 shows a cross-sectional view of a part of a second component 11, where said part of the second component 11 includes said connection aperture 12. In the embodiment represented in Figure 6, the connection aperture 12 is formed by the central part of an annular connection element 13. The connection aperture 12, as represented in the figure, is thus circular and has a diameter which is slightly larger than the diameter Dg of the stalk head 6. Thus, the stalk head 6 can be inserted as a whole through the connection aperture of the connection element 13. To this end, the connection aperture 12 in the annular connection element 13, over the full height of the connection aperture 12, has a diameter that is larger than the maximum diameter Dg of the stalk head 6. Normally, the height of the connection aperture 12 corresponds to the thickness of the annular connection element 13 in a direction transverse to the diameter of the opening 12.

[0049] Thus, the diameter Dg of the stalk head 6 is smaller than the diameter of the connection aperture 12, and the diameter of this connection aperture 12 is larger than the diameter D5of the spindle element 5. This allows the second component 11 with the connection aperture 12 to slide over the stalk head 6 of the fastening stalk 1 up to over the spindle element 5.

[0050] The spindle element 5 is preferably axially symmetrical, wherein the central axis 20 of the spindle element 5 extends along the longitudinal direction of the fastening stalk 1. The spindle element 5 preferably has a circular cross-section in this case. This ensures that the second component 11 can rotate smoothly around the central axis 20 of the spindle element 5 when it is connected to the first component 2 by means of the fastening stalk 1. In this respect, it is also interesting that the connection aperture 12 has a circular shape.

[0051] The surface of the spindle element 5, as represented in Figures 1 to 6, is preferably defined by a concave surface of revolution. Thus, according to the central axis 20 thereof, it has a minimum diameter at half its height and a maximum diameter at the connection to the first component 3 and to the fixing shaft 7. Such a shape ensures that the second component 11 can also undergo a limited rotation around the spindle element 5, around an axis extending transversely with respect to the central axis 20. The latter is relevant, for example, to allow lateral displacements of the jaws with respect to each other when the fastening stalk 1 is used to connect a jaw displacer, such as a Herbst appliance, to a jaw. The surface of the spindle element 5, or said concave surface of revolution, is thus defined, for example, by a portion of a hyperboloid or of a torus. However, it goes without saying that the spindle element 5 may also be formed by a cylinder. In addition, it is also possible that, instead of a circular cross-section, it has a cross-section in the form of an ellipse or any other shape around which the second component 11 may rotate via the connection aperture 12. For example, in certain cases, a spindle element 5 may be chosen having a cross-section in the form of a polygon, such as, for example, a regular octagon.

[0052] When the spindle element 5 is inserted through the connection aperture 12 of the second component 11, the locking member 8 is placed around the fixing shaft 7 so that the second component 11 is locked via the connection aperture to the fastening stalk 1 which is fixed to the first component 3, as shown in Figure 6. However, for this purpose, it is important that the external diameter D8of the locking member 8 is larger than the diameter of the connection aperture 12 when the locking member 8 extends around the fixing shaft 7.

[0053] In order to thus connect the first component 3 with the second component 11 by means of the connection system according to the invention, the annular connection element 13 with the connection aperture 12 is first slid entirely over the stalk head 6 so that the spindle element 5 protrudes through the opening 12. Next, the locking member 8 is slid over the stalk head 6 up to around the fixing shaft 7 so that this locking member extends between the connection element 13 and the stalk head 6. In this way, both components 3 and 11 are connected to each other in such a way that they can still move relative to each other and can undergo a rotational movement relative to each other. In addition, the locking member 8 must always be removed from the fastening stalk 1 before the connection aperture 12 can be moved over the stalk head 6 in order to detach both components 3 and 11 from each other.

[0054] Since the diameter of the connection aperture 12 is smaller than the diameter of the locking member 8 around the fixing shaft, the second component 11 is prevented from inadvertently being detached from the fastening stalk 1 or thus from the first component 1. On the other hand, the internal diameter ds of the locking member 8 is smaller than the diameter Dsof the stalk head 6 so that the locking member 8 cannot be inadvertently removed from the fastening stalk 1.

[0055] Additionally, the locking member 8 preferably has a rectangular crosssection, as shown in the figures. The ring 9 represented in Figures 4, 5 and 6 has such a rectangular cross-section. This additionally ensures that the ring 9 cannot unintentionally slide over the stalk head 6 and could therefore be unintentionally removed from the fastening stalk 1.

[0056] In addition, the side of the stalk head 6 that connects to the fixing shaft 7 preferably forms an annular flat surface 14 that extends almost transversely to the axial direction of the fixing shaft 7 and connects to this fixing shaft 7. This ensures that a certain adhesion may occur between the ring 9 and this surface 14 so that the unintentional removal of the ring 9 from the fixing shaft 7 is additionally prevented. To this end, the surface 14 may optionally also be concave in a radial direction.

[0057] When both components 3 and 11 are connected to each other via the connection system according to the invention, in particular by means of the fastening stalk 1, the connection element 13 with the connection aperture 12, the locking member 8 and the stalk head 6 thus successively extend along the central axis 20 or the longitudinal direction of the fastening stalk 1. Thus, the locking member 8 is not enclosed so that the locking member 8 is freely accessible for removal independently of the second component 11 of the fastening stalk 1.

[0058] When the locking member 8 is formed by an elastic ring 9, as shown for example in Figures 4 to 6, the cross-section of the stalk head 6 will preferably gradually increase from the second end 4 of the fastening stalk 1 towards the fixing shaft 7. More specifically, in a plane transverse to the longitudinal direction of the fastening stalk 1, the diameter of the stalk head 6 increases from said second end 4 of the fastening stalk 1 to said first end 2. Thus, the stalk head 6 has the shape of, for example, a truncated cone, a spherical segment, a spherical cap or the like.

[0059] A stalk head 6 with such a shape is particularly interesting to easily apply a locking member 8 formed by an elastic closed ring 9. In this case, the ring 9 is placed, for example with a finger, against the second end 4 of the fastening stalk 1, or in other words against the narrowest part of the stalk head 6. Due to the preferably axially-symmetrical shape of the stalk head 6, the ring 9 centres itself almost automatically around the stalk head 6. When the ring 9 is subsequently pressed against the stalk head 6, the ring 9 will elastically deform and slide with its internal wall 10 over the stalk head 6 while its internal diameter gradually increases, as does the elastic deformation. When the ring 9 is partially opposite the fixing shaft 7, the ring 9 will slide further almost automatically as a result of its elastic action, its internal diameter decreasing again, until it extends completely around the fixing shaft 7. When the elastic ring 9 needs to be removed again from the fixing shaft 7 , for example, to remove a jaw displacer from the fastening stalk 1, this can be done by inserting a needle-shaped part of a dental instrument between the fastening stalk 1 and the ring 9 and by then pulling the ring over the stalk head 6 with this needle-shaped part. A dental instrument suitable for this purpose is shown in Figure 9 and is also known as a dental probe 15. Such an instrument is formed by a rod-shaped handle 16, one end of which forms a needle-shaped pin 17 extending into a fine tip 18. Thus, in order to remove the locking member 8, or more specifically the elastic ring 9, from the fixing shaft 7, it is important that it is not enclosed so that the locking member 8 is accessible for removal, for example using said dental instrument.

[0060] According to an interesting embodiment of the fastening stalk 1 according to the invention, said stalk head 6 is provided with a lateral recess which leads to the surface of the fastening stalk 1 and extends at least up to the fixing shaft 7. This recess 19 is shown, for example, in Figures 1 to 3 and Figure 6 and allows an elastic ring 9 to be removed from the fastening stalk 1 in a simple manner. Preferably, this recess 19 extends from the stalk head 6 to the spindle element 5.

[0061] In order to thus remove an elastic ring 9 from the fixing shaft 7 when such a recess 19 is present, the needle-shaped pin 17 on the stalk head 6 is inserted into the recess 19 and then pushed further into this recess between the ring 9 and the fixing shaft 7 until the tip 18 of the pin 17 has almost reached the spindle element 5. The pin 17 can then be tilted so that the ring 9 elastically deforms and is pulled over the stalk head 6 to thus remove the ring 9 from the fastening stalk 1. In order to allow a needle-shaped pin to be easily inserted into the recess 19, it is preferably made rectilinear.

[0062] Figures 7 and 8 show an alternative embodiment of the fastening stalk 1. In this embodiment, the spindle element 5 and the fixing shaft 7 have the same diameter.

[0063] In the embodiments of the fastening stalk 1 shown in the figures, it has a central axis 20, whereby the pivot element 5, the stalk head 6 and the fixing shaft 7 are coaxial with this central axis 20. The fastening stalk 1 also has a circular cross-section over its entire length along this central axis 20.

[0064] However, in embodiments of the fastening stalk 1 according to the invention that are not represented in the figures, it is not necessary for the spindle element 5, the stalk head 6 and the fixing shaft 7 to be coaxial with the central axis 20. They may, for example, be slightly offset with respect to each other. The fastening stalk 1 of the appliance according to the invention is fixed via its first end 2 to a first component 3. This first component is preferably an anchor element to be fixed in a fixed position on an upper or lower jaw. Thus, this anchor element is, for example, a frame which is provided to fit neatly onto the teeth of an upper or lower jaw, or a bone anchor.

[0065] Figure 10 shows an example of a frame 21 forming said first component 3 and provided with two fastening stalks 1. This frame 21 is neatly attached to teeth 22, more specifically molars, of an upper jaw 23. This frame thus ensures that the fastening stalks 1 of the appliance according to the invention are firmly and virtually immovably connected to the jaw 23. The longitudinal direction or the central axis 20 of the fastening stalks 1 extends transversely to the dental arch of the upper jaw 23 so that the stalk head 6 can be relatively easily reached in the oral cavity in order to, for example, apply or remove a locking member 8.

[0066] The frame 21 is provided to rigidly connect molars of the same quadrant of the upper jaw 23. Such a frame 9 is custom-made for each patient. For this purpose, an intra-oral scan of at least the molars of the upper jaw of a patient is performed, for example, and based on the data obtained from this scan, a frame 21 is then digitally designed and manufactured for both quadrants of the upper jaw 23 by means of, for example, a so-called rapid-prototyping technique, such as selective laser melting (SLM). Preferably, this involves manufacturing the frame 21 in one piece together with the fastening stalks 1 provided thereon. Usually, it is decided to manufacture the frame from a chromium-cobalt alloy or from titanium.

[0067] Of course, it is also possible to manufacture such a frame 21 in a manner known as such, starting from a physical model of the upper jaw.

[0068] The frame 21 is formed by a rigid structure that must connect laterally to the molars 22 of the upper jaw. It is usually decided to rigidly connect the first premolar, the second premolar and the first molar of the same quadrant of the upper jaw 23 by means of this structure.

[0069] Figure 11 shows a lateral view of the upper jaw from figure 10 together with a lower jaw 24. In this case, the frame 21 is connected, via the fastening stalk 1 fixed to it, to a second component 11 formed by a jaw displacer 25. This jaw displacer 25 is also shown in Figures 12 to 14.

[0070] The jaw displacer 25 includes a rod 26 and a rod guide 27, wherein the rod 26 connects to a first end 28 of the jaw displacer 25 and the rod guide 27 connects to a second end 29 of the jaw displacer 25 opposite said first end 28. The rod 26 is movable relative to the rod guide 27 in the longitudinal direction of the latter. In the embodiment shown, the rod guide 27 is hollow in order to allow the rod 26 to be moved and guided in the rod guide 27 in its longitudinal direction. The jaw displacer 25 thus forms what is called a Herbst appliance.

[0071] As shown in Figure 11, the first end 28 of the jaw displacer 25 is detachably fixed to a bone anchor 30, while the opposite second end 29 of the jaw displacer

[0072] 25 is connected to the frame 21 via said fastening stalk 1 according to the invention.

[0073] The second end 29 of the jaw displacer 25 is provided with an annular connection element 13 which thus defines a connection aperture 12. In Figure 11, the fastening stalk 1 protrudes through the connection aperture 12 of this connection element 13 and an elastic ring 9 is slid over the stalk head 6 in order to detachably lock the jaw displacer to the frame 21. This corresponds to the situation as is schematically shown in Figure 6.

[0074] The first end 28 of the jaw displacer 25 also has an annular connection element 13 defining a circular connection aperture 12. This connection element 13 at the first end 28 is therefore fixed to one end of the rod 26. In the embodiment of the appliance shown in Figure 11, this connection element 13 is attached to a hook 31 which is part of the bone anchor 30 fixed to the lower jaw 24.

[0075] The bone anchor 30 is mounted against the bone of the lower jaw 24. To this end, the bone anchor 30 includes a fixation plate 32 to fix it against the bone of the jaw 24. This fixation plate 32 is connected to a connection element 33 which extends into a mounting device that includes said hook 31. The connection element 33 should protrude through the gums when the bone anchor 30 is fixed to the bone of the jaw 24 so that the hook 31 is located in the oral cavity. The connection element 33 forms a rod with a circular cross-section.

[0076] The appliance according to the invention, shown in Figures 10 and 11, allows the lower jaw 24 to be displaced in a ventral direction relative to the upper jaw 23. Upon closing the mouth, the rod 26 slides almost entirely into the rod guide 27 up against a collar on the rod 26. As the mouth is closed further, any further displacement of the rod

[0077] 26 in the rod guide 27 is no longer possible, as a result of which the jaw displacer 25 will exert a compressive force between its two ends 28 and 29, pushing the lower jaw 24 forward relative to the upper jaw 23. As the jaws 23 and 24 move relative to each other, the jaw displacer 25 rotates around the central axis 20 of the fastening stalk 1 via the annular connection element 13. Moreover, the connection between the jaw displacer 25 and the frame 21 also allows for a displacement around an axis that extends almost transversely to the central axis 20, so that it is possible to move the jaws somewhat laterally relative to each other in order to allow chewing movements, for example. The operation of the connection between the jaw displacer 25 and the frame 21 is thus somewhat similar to the operation of a ball joint.

[0078] As a function of the progression of a treatment in which the anterior jaw 23 is forced forward by means of the jaw displacer 25, as shown in Figure 11, it is important to regularly replace the rod 26 or rod guide 28 with a rod 26 or rod guide 28 of greater length so that a further displacement of the lower jaw 24 relative to the upper jaw 23 can be obtained. In such a case, the locking member 8 can be simply removed from the fixing stem 1, as described above, and after adjusting the length of the jaw displacer 25, it is very easily reattached to the frame 21 via the fastening stalk 1 and locked by sliding an elastic ring 9 over the stalk head 6 again.

[0079] Figure 15 shows, byway of example, an alternative embodiment of a jaw displacer 25. It is additionally provided with a helical compression spring 34 that is coaxial with the rod 26. This spring exerts a compressive force between said rod guide 27 on the one hand and a collar provided on the rod 26 on the other hand. Thus, this compression spring ensures, for example, that the movement of the rod 26 with respect to the rod guide is somewhat dampened and that a compressive force is always exerted between the ends 28 and 29 of the jaw displacer 25. The latter thus ensures that a continuous force is exerted on the lower jaw in the ventral direction.

[0080] Figure 16 shows a situation in which a jaw displacer 25 is mounted between two bone anchors 30, each provided with a connecting system having a fastening stalk 1 according to the invention. To this end, a fastening stalk 1 is provided at the end of the connection element 33 of these bone anchors 30 extending into the oral cavity. The orientation of these fastening stalks 1 in the oral cavity may possibly be adjusted depending on the specific situation of a patient. An example of a potentially suitable bone anchor 30 is shown in Figure 17, for example. In this case, the bone anchor 30 adjacent to said first end 2 of the fastening stalk has a thickening whose diameter is larger than that of the connection aperture 12 provided on the jaw displacer 25. Thus, this thickening prevents the bone anchor from sliding past said first end 2. When in the above description the diameter of the fastening stalk 1, the spindle element 5, the stalk head 6, the fixing shaft 7 , the locking member 8, the ring 9 or the connection aperture 12 is mentioned, usually the diameter in a plane transverse to said central axis 20 is being referred to.

Claims

CLAIMS1. Orthodontic or orthopaedic appliance having a connection system for detachably connecting two components (3,11) of the appliance, wherein said connection system is provided with a fastening stalk (1) with a first end (2) to be firmly connected to a first component (3) of said components (3,11), a connection aperture (12) having a diameter that is part of a second component (11) of said components (3, 11), and an elastic ring-shaped locking member (8) having an internal diameter (dg) and an external diameter (Dg), wherein the external diameter (Dg) of the locking member is larger than the diameter of said connection aperture (12), wherein the fastening stalk (1) has a spindle element (5) connecting to said first end (2), the diameter of the spindle element (5) being smaller than the diameter of said connection aperture (12) and wherein a second end (4) of the fastening stalk (1) opposite said first end (2) has a stalk head (6) whose diameter (Dg) is larger than the internal diameter (dg) of the locking member (8) and smaller than the diameter of said connection aperture (12), whereas a fixing shaft (7) having a diameter (d7) which is smaller than the diameter (Dg) of the stalk head (6) extends between the stalk head (6) and said spindle element (5), characterised in that the diameter (Dg) of the stalk head (6) is smaller than the diameter of the connection aperture (12), so that the second component (11) can be slid over the stalk head (6) by means of the connection aperture (12) up to over the spindle element (5), such that the spindle element (5) protrudes through the connection aperture (12) and the locking member (8) can extend around the fixing shaft (7) between the stalk head (6) and the second component (11).

2. Appliance according to claim 1, wherein the connection aperture (12), the locking member (8) and the stalk head (6) extend successively along the length of the fastening stalk (1), with the locking member (8) not being enclosed.

3. Appliance according to claim 1 or 2, wherein said second component (11) comprises a connection element (13) provided to cooperate with said fastening stalk (1), wherein the connection element (13) is provided with said connection aperture (12).

4. Appliance according to claim 3, wherein said connection element(13) is annular.

5. Appliance according to claim 3 or 4, wherein said connection aperture (12) has a diameter which is larger than the diameter (Dg) of said stalk head (6), wherein the height of the connection aperture (12) corresponds to the thickness of the connection element (13) in a direction perpendicular to the diameter of the opening (12).

6. Appliance according to any one of claims 1 to 5, wherein said connection aperture (12) is circular.

7. Appliance according to any one of claims 1 to 6, wherein said stalk head (6) has an annular surface (14) extending almost transversely to the axial direction (20) of the fixing shaft (7) and connecting to this fixing shaft (7).

8. Appliance according to any one of claims 1 to 7 , wherein said locking member (8) is annular and made of an elastomer or rubber.

9. Appliance according to any one of claims 1 to 7 , wherein said locking member (8) comprises a circlip.

10. Appliance according to any one of claims 1 to 9, wherein said locking member (8) forms a ring (9) with a rectangular cross-section.

11. Appliance according to any one of claims 1 to 10, wherein said locking member (8) forms a closed ring (9).

12. Appliance according to any one of claims 1 to 11, wherein said stalk head (6) has a lateral recess (19) leading to the surface of the fastening stalk (1) and extending at least to said fixing shaft (7).

13. Appliance according to claim 12, wherein said recess (19) extends as of said stalk head (6) up to the spindle element (5).

14. Appliance according to any one of claims 1 to 13, wherein the diameter of the stalk head (6) in a plane transverse to the longitudinal direction of the fastening stalk (1) increases from said second end (4) of the fastening stalk (1) to said first end (2).

15. Appliance according to any one of claims 1 to 14, wherein said fastening stalk (1) has a central axis (20) and wherein the spindle element (5), the stalk head (6) and the fixing shaft (7) are coaxial.

16. Appliance according to any one of claims 1 to 15, wherein the spindle element (5) and the fixing shaft (7) have the same diameter.

17. Appliance according to any one of claims 1 to 16, wherein said fastening stalk (1) has a central axis (20) and a circular cross-section.

18. Appliance according to any one of claims 1 to 17, wherein said spindle element (5) has a concave surface of revolution.

19. Appliance according to any one of claims 1 to 18, wherein said spindle element (5) describes a surface forming part of a hyperboloid or of a torus.

20. Appliance according to any one of claims 1 to 19, wherein said two components (3,11) form a jaw displacer (25) and an anchor element respectively, wherein the anchor element is provided to be rigidly fixed relative to an upper or lower jaw (23,24).

21. Appliance according to any one of claims 1 to 20, wherein said first component (3) forms the anchor element.

22. Appliance according to claim 20 or 21, wherein said anchor element includes a bone anchor (30) or a frame (21), wherein the frame (21) is provided so as to fit neatly onto teeth (22) of an upper or lower jaw (23,24).

23. Appliance according to claim 22, wherein said bone anchor (30) comprises a fixation plate (32) provided to fasten the bone anchor (30) against the bone of an upper or lower jaw (23,24), wherein said fixation plate (32) is connected to a connection element (33) that leads to a mounting device comprising said fastening stalk (1) and wherein the connection element (33) should protrude through the gums when the bone anchor (30) is fastened to said bone so that the mounting device is located in the oral cavity.

24. Appliance according to any one of claims 1 to 23, wherein said second component (11) forms a jaw displacer (25), wherein an end (28,29) of said jaw displacer (25) is provided with said connection aperture (12).

25. Appliance according to claim 24, wherein said jaw displacer (25) includes a rod (26) and a rod guide (27), wherein the rod (26) connects to a first end (28) of the jaw displacer (25) and the rod guide (27) connects to a second end (29) of the jaw displacer (25) opposite said first end (28), wherein the rod (26) can be moved in the longitudinal direction of the rod guide (27) with respect to the latter.

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