Orthodontic device

Abstract

The invention relates to an orthodontic device capable of causing a displacement of a mandible relative to a maxilla, comprising a lower part attached to said mandible, an upper part attached to said maxilla, and two telescopic rods (3) connecting the upper and lower parts, said device comprising, for each rod (3), coupling means (4) with the lower part and with the upper part, each coupling means (4) comprising a connecting piece (5) movable relative to one of the ends of said rod (3), characterized in that for at least one coupling means (4), said device comprises a wire (7) the first end of which is attached to said connecting piece (5), and the second end is fixed to the corresponding lower or upper part, said wire (7) being configured so as to be able to be twisted by a practitioner after fixing said device on a patient.Figure for the summary: Fig 3.

Description

Title of the invention: Orthodontic device Technical field

[0001] The present invention is in the field of orthodontics. It relates more particularly to an orthodontic device capable of causing a displacement of a mandible relative to a maxilla and comprising in particular two connecting rods. The invention makes it possible to have a device that can be adjusted after placement on the patient, in order to be as well adapted as possible to their morphology and their treatment program. Prior art

[0002] Various solutions have been proposed to cause a displacement of the mandible relative to the maxilla. The aim is to move the mandible relative to its original position by a very small distance, of the order of a few millimeters, initially, in order, in particular, to stimulate growth. This mandibular propulsion can be used as part of a class II or class III orthodontic treatment, or to increase respiratory flow, in order to resolve problems of sleep apnea syndromes.

[0003] The invention relates more particularly to an orthodontic assembly of the type perfectly known to a person skilled in the art, under the name of “Herbst orthosis” or “Herbst connecting rods”.

[0004] Essentially, this type of orthosis has gutters cooperating, respectively, with the upper row of teeth and the lower row of teeth. These gutters are generally made of a rigid material, for example thermoformed acrylic resin, and are connected to each other by a system of rods mounted with sliding capacity. More particularly, two metal rods are arranged, respectively, on each side of the upper gutter and the lower gutter. The two rods are connected with articulation capacity to the gutters usually by means of a frame, substantially at the level of the first molars for the upper gutter and substantially at the level of the canine for the lower gutter.

[0005] Document EP2198802 proposes an orthodontic device of this type. A disadvantage of this device is that since the framework and the connecting rods are rigid, it is necessary to manufacture them very precisely in order to best adapt to the patient's morphology and the treatment program. In some cases, these elements do not correspond perfectly to the patient, which results either in suboptimal treatment or in the manufacture of one of the elements again, which generates costs and a loss of time. This problem is all the more common since the device being most often used in children, its morphology changes constantly and sometimes unexpectedly with growth. Statement of the invention

[0006] The present invention aims to overcome these drawbacks by proposing an orthodontic device comprising a wire which can be twisted after placement on the patient, in order to finely adjust the position of the connecting rods on the patient.

[0007] For this purpose, the invention relates to an orthodontic device capable of causing a displacement of a mandible relative to a maxilla, comprising a lower part secured to said mandible, an upper part secured to said maxilla, and two telescopic links connecting the upper and lower parts, said device comprising, for each link, means for coupling with the lower part and with the upper part, each coupling means comprising a connecting piece movable relative to one of the ends of said link, characterized in that for at least one coupling means, said device comprises a wire of which a first end is secured to said connecting piece, and the second end is fixed to the corresponding lower or upper part, the wire being configured to be able to be twisted by a practitioner after fixing said device on a patient.

[0008] Thanks to these provisions, the orthodontic device can be adjusted after placement on the patient, which allows it to be best adapted to the patient's anatomy and the treatment program. In particular, the lateral position and the inclination of the connecting rods can be finely adjusted, in order to be best adapted to the joints of the mouth.

[0009] Said wire may have a diameter of between 0.9 and 2.0 mm, which, given the materials conventionally used in orthodontics, allows it to be sufficiently flexible to be twisted by hand, in particular with pliers, after placement on a patient, but not too flexible for this twisting to be lasting.

[0010] Said wire may have a modulus of rigidity of between 65 and 90 GPa and a modulus of elasticity of between 150 and 230 GPa, which makes it possible to obtain the desired flexibility and resistance so that the wire can bend without breaking, while maintaining its bent shape.

[0011] Said wire can be made of chrome-cobalt alloy or stainless steel, inexpensive and effective materials.

[0012] Cobalt chrome is preferred because it is generally more soft and flexible than stainless steel. Cobalt chrome is a metal alloy used primarily in dentistry and orthopedics, including the manufacture of dentures, implants, and medical devices. It is valued for its high strength, durability, and biocompatibility.

[0013] Compared to stainless steel, cobalt-chromium has a flexural strength superior, meaning it can bend and flex without breaking easily.

[0014] In each coupling means, said connecting piece may be a ball joint arranged in a hemispherical cage of an end piece located at the end of the connecting rod and secured to this end, which makes it possible to give the connecting rod a great freedom of mobility relative to its fixing points on the patient.

[0015] A second section of said wire comprising its second end can be embedded in a maxillary or mandibular plate, which is a simple and robust embodiment of the invention.

[0016] In each coupling means, said connecting piece may be integral with a rod arranged in a fixing piece, a first section of said wire comprising its first end being able to be arranged in a housing of said fixing piece so as to be kept rectilinear, which is a simple means of achieving the desired mobility of the connecting rods relative to the patient's jaw.

[0017] Said first section may have a length of between 2.0 and 3.0 mm, which makes it possible to fix the wire in a sufficiently strong manner to be able to twist it without this fixing risking breaking.

[0018] Said rod can be oriented substantially perpendicular to said first section of said wire, which makes it possible to optimize the size of the device according to the invention in the patient's mouth.

[0019] Said wire may comprise a free section located between the first and second sections, said free section measuring between 10 and 20 mm, which gives the orthodontist sufficient space to perform a twisting of the wire.

[0020] The present invention also relates to a method of manufacturing an orthodontic device according to the invention, characterized in that said first section is fixed in the housing of the fixing part by brazing, said fixing part comprising at least one passage between the exterior of said fixing part and said housing, a filler metal being deposited in said passage.

[0021] Thanks to these arrangements, the attachment of the wire to the fixing part is solid and does not risk breaking when the wire is twisted. Brief description of the drawings

[0022] The present invention and its advantages will appear better in the following description of several embodiments given as non-limiting examples, with reference to the appended drawings, in which:

[0023] [Fig-1] is a schematic view of a preferred embodiment of a device or thodontic device according to the invention before placement on a patient, the upper wire being shown outside the device.

[0024] [Fig.2] is an exploded view of a detail of [Fig.l].

[0025] [Fig.3] is a perspective view of the orthodontic device of [Fig.l], placed on a dental cast, in the closed jaw position.

[0026] [Fig.4] is a front view of the orthodontic device of [Fig.l], placed on a dental cast, in open jaw position.

[0027] [Fig.5] is a front view of the orthodontic device of [Fig.l], placed on a dental cast, in closed jaw position and with a lateral shift of the maxilla relative to the mandible.

[0028] [Fig.6] is a front view of the orthodontic device of [Fig.l], placed on a dental cast, the maxilla and mandible being laid flat, the lower and upper elements of the connecting rods being separated.

[0029] [Fig.7] is a perspective view of the orthodontic device of [Fig.l], in closed jaw position. Description of the embodiments

[0030] In the illustrated embodiments, identical elements or parts bear the same reference numbers. Furthermore, terms which have a relative meaning, such as vertical, horizontal, right, left, front, rear, above, below, etc. must be interpreted under normal conditions of use of the invention, and as shown in the figures. Furthermore, the geometric positions indicated in the description, such as “perpendicular”, “parallel”, “symmetrical” are not limited to the strict sense defined in geometry, but extend to geometric positions which are close, that is to say which accept a certain tolerance in the technical field considered, without influence on the result obtained. This tolerance is notably introduced by the adverb “substantially”, without this term necessarily being repeated before each adjective.

[0031] With reference to the figures, the orthodontic device according to the invention is capable of causing a displacement of a mandible 1 relative to a maxilla 2. The orthodontic device comprises a lower part, secured to the mandible 1, an upper part, secured to the maxilla 2, and two telescopic links 3, connecting the upper and lower parts. A first link 3 is located on the right of the patient, for example substantially at the level of the first right molars for the top of the link 3, and for example substantially at the level of the right canine for the bottom of the link 3. The second link 3 is located on the left of the patient, for example substantially at the level of the first left molars for the top of the link 3, and for example substantially at the level of the left canine for the bottom of the link 3.

[0032] In the context of the present invention, the term "link" designates a set of two elongated elements, one sliding in the other so that the total length of the connecting rod is variable. Usually in the devices according to the invention, it is the lower element which slides in the upper element.

[0033] The orthodontic device according to the invention also comprises, for each connecting rod 3, coupling means 4 with, on the one hand, the upper part of the device, and on the other hand with the lower part of the device.

[0034] The coupling means 4 preferably allow significant freedom of movement of the connecting rods relative to the jaw. Such mobility is visible in [Fig.4] with an upward movement of the maxilla relative to the connecting rods, and in [Fig.5] with a lateral movement of the top of the connecting rods relative to the mandible.

[0035] The coupling means 4 each comprise a connecting piece 5. In a preferred embodiment of the invention, the connecting piece 5 is a ball joint arranged in a hemispherical cage of an end piece 6 located at the corresponding end of the connecting rod 3 and secured to this end.

[0036] More particularly, the articulation of the connecting rods 3 with a ball joint 5 may be as described in document EP2198802, in order to allow total freedom of articulation of the connecting rods 3 both in an anteroposterior plane and in a lateral plane, and this in a reduced bulk.

[0037] At at least one coupling means 4, the orthodontic device according to the invention comprises a wire 7, a first end of which is secured to said connecting piece, and the second end is fixed to the corresponding lower or upper part.

[0038] The wire 7 is configured to be able to be twisted after the device according to the invention has been placed on a patient. Thus, the orthodontist can finely adapt the position of the connecting rods 3 relative to the mandible and maxilla of the patient, so that the movement of one relative to the other is optimal and in accordance with the treatment program. Small manufacturing inaccuracies or an imperfect match between the orthodontic device and the anatomy of the patient, for example, can be corrected by this twisting step.

[0039] A wire 7 may be located on the upper coupling means 4, between the upper part of the device and the connecting rods 3, or on the lower coupling means 4, between the lower part of the device and the connecting rods 3. Preferably, the device according to the invention comprises a wire 7 at each coupling means 4.

[0040] The attachment of the first end of the wire 7 to the connecting piece 5 can be carried out in various ways. In the embodiment illustrated in [Fig.l] and 2, this attachment is carried out by means of a fixing piece 8. The attachment is particularly visible in [Fig.2], with an exploded view along an axis A. The fixing piece 8 is made integral with the connecting piece 5, for example by means of a rod 9 secured to the connecting piece 5. The rod 9 is for example welded or formed in one piece with the connecting piece 5. The rod 9 can be threaded, so that it can be fixed in a corresponding thread of the fixing piece 8, or it can be clipped, or any other means of assembly with the fixing piece 8.

[0041] In a preferred embodiment, an example of which is illustrated in [Fig. 1] and 2, the rod 9 is oriented substantially perpendicular to the first section of the wire 7. This allows for minimum bulk of the device according to the invention.

[0042] The first end of the wire 7 is then made integral with the fixing part 8. Preferably, a first section 7a comprising the first end of the wire 7 is arranged in a housing of the fixing part 8, in order to be kept rectilinear. This allows a solid anchoring of the wire 7 relative to the connecting rods 3, and makes it possible to prevent the first end of the wire 7 from moving during its twisting. To achieve this result, the first section 7a of the wire 7 preferably has a length of between 2.0 and 3.0 mm, for example 2.5 mm.

[0043] The first section 7a is visible in [Fig.l]. In this figure, in the upper coupling means 4, the first section 7a is not inserted into the housing of the connecting piece 8, whereas in the lower coupling means 4, the first section 7a is inserted into the housing of the connecting piece 8.

[0044] The first section 7a may be secured in the housing of the fastening part 8 by any suitable technique, such as gluing, brazing or laser welding. The fastening part 8 preferably comprises at least one passage 8a between the exterior of the part and the housing, such as at least one window or slot. The passage 8a is oriented laterally, that is to say it gives access to one side of the first section 7a of the wire 7 when it is in the housing. The passage 8a allows the deposition of a filler metal, in the case of brazing, or of an adhesive, in order to secure the wire 7 and the fastening part 8 together.

[0045] The attachment of the second end of the wire 7 to the corresponding lower or upper part of the device may vary depending on the type of lower or upper part. In a preferred embodiment, illustrated in particular by [Fig. 6] and 7, the lower part comprises a mandibular plate 10 and the upper part a maxillary plate 11, also called a palatal plate, and a second section 7b of the wire 7 comprising its second end is embedded in the corresponding plate, as illustrated in [Fig. 6] and 7. Such a plate is generally made of acrylic resin.

[0046] The wire 7 has a free section to which the orthodontist has access, and on which he can perform the torsion. In the embodiment of [Fig.l] to 7, the free section is located between the first section 7a and the second section 7b. The free section has a length preferably between 10 and 20 mm, for example 15 mm, which gives the orthodontist sufficient freedom of movement to perform the torsion, while maintaining sufficient rigidity so that the orthodontic device can be effective.

[0047] The wire 7 has the flexibility necessary to be twisted by an orthodontist, but it is not too flexible, so that its orientation and shape are not altered during normal wearing of the orthodontic device by the patient, and the twisting carried out by the orthodontist is durable. The twisting can be carried out with a manual tool, such as pliers, or by a machine.

[0048] The wire 7 can be made of any material compatible with orthodontics and sufficiently strong and flexible, such as a chrome-cobalt alloy, a polyetheretherketone (PEEK), or even a polyaryletherketone (PAEK).

[0049] In the context of the present invention, the term “chromium-cobalt alloy” designates any alloy in which the sum of the chromium and cobalt contents is greater than or equal to 50%.

[0050] The wire 7 preferably has a diameter of between 0.9 and 2.0 mm, for example 1.3 mm.

[0051] The rigidity modulus of the wire 7 may be between 65 and 90 GPa, preferably between 75 and 80 GPa, for example 77 GPa.

[0052] The wire 7 preferably has a hard elasticity, that is to say that in the event of high tensions, it undergoes only little deformation. The modulus of elasticity of the wire 7 may be between 150 and 230 GPa, preferably between 180 and 200 GPa for example 190 GPa.

[0053] The present invention is of course not limited to the embodiments described but extends to any modification and variant obvious to a person skilled in the art. Furthermore, the technical characteristics of the different embodiments and variants mentioned above may be, in whole or in some cases, combined with each other.

Claims

Claims

1. Orthodontic device capable of causing a displacement of a mandible relative to a maxilla, comprising a lower part secured to said mandible, an upper part secured to said maxilla, and two telescopic connecting rods (3) connecting the upper and lower parts, said device comprising, for each connecting rod (3), coupling means (4) with the lower part and with the upper part, each coupling means (4) comprising a connecting piece (5) movable relative to one of the ends of said connecting rod (3), characterized in that for at least one coupling means (4), said device comprises a wire (7) of which a first end is secured to said connecting piece (5), and the second end is fixed to the corresponding lower or upper part, said wire (7) being configured to be able to be twisted by a practitioner after fixing said device on a patient.

2. Orthodontic device according to claim 1, characterized in that said wire (7) has a diameter between 0.9 and 2.0 mm.

3. Orthodontic device according to any one of claims 1 to 2, characterized in that said wire (7) has a modulus of rigidity of between 65 and 90 GPa and a modulus of elasticity of between 150 and 230 GPa.

4. Orthodontic device according to any one of claims 1 to 3, characterized in that said wire (7) is made of chrome-cobalt alloy or stainless steel.

5. Orthodontic device according to any one of claims 1 to 4, characterized in that in each coupling means (4) said connecting piece (5) is a ball joint arranged in a hemispherical cage of an end piece (6) located at the end of the connecting rod (3) and integral with this end.

6. Orthodontic device according to any one of claims 1 to 5, characterized in that a second section (7b) of said wire (7) comprising its second end is embedded in a maxillary (11) or mandibular (10) plate.

7. Orthodontic device according to any one of claims 1 to 6, characterized in that in each coupling means (4), said connecting piece (5) is integral with a rod (9) arranged in a fixing piece (8), a first section (7a) of said wire (7) comprising its first end being arranged in a housing of said fixing part (8) so as to be kept rectilinear.

8. Orthodontic device according to claim 7, characterized in that said first section (7a) has a length of between 2.0 and 3.0 mm

9. iliili. Orthodontic device according to any one of claims 7 to 8, characterized in that said rod (9) is oriented substantially perpendicular to said first section (7a) of said wire (7).

10. Orthodontic device according to claim 6 and any one of claims 7 to 9, characterized in that said wire (7) comprises a free section located between the first section (7a) and the second section (7b), said free section measuring between 10 and 20 mm.

11. A method of manufacturing an orthodontic device according to any one of claims 7 to 10, characterized in that said first section (7a) is fixed in the housing of the fixing part (8) by brazing, said fixing part (8) comprising at least one passage (8a) between the exterior of said fixing part (8) and said housing, a filler metal being deposited in said passage (8a).

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