Orthodontic retention device and assistance system for fitting such a device

Abstract

Orthodontic retention device (1) intended to extend over at least {2+N} teeth (101), the device (1) comprising rigid plates (2) and at least one connecting element (6) rigidly fixed to the plates (2), the device (1) being characterized in that it comprises at least {2+2N} plates (2), namely two plates (2) called end plates and at least two plates (2) called intermediate plates, and in that said at least two intermediate plates (2) are configured to be rigidly fixed on the same face (101a, 101b) of the same tooth (101) of the patient, and form a pair of intermediate plates (2) between the two end plates (2). Figure for the abstract: figure 2

Description

Title of the invention: Orthodontic retention device and assistance system for fitting such a device FIELD OF THE INVENTION

[0001] The present invention relates to the field of orthodontics, and more precisely to the field of fixed, intra-oral orthodontic retention systems intended to be applied, but not exclusively, to the lingual surface of the teeth. TECHNOLOGICAL BACKGROUND

[0002] After orthodontic treatment, for example aimed at restoring alignment of a patient's teeth, it is not uncommon to see, after a certain time, a partial or total reappearance of the initial dental malpositions. This is called relapse.

[0003] To limit the risk of recurrence, it is known to prescribe a retention device to the patient in order to maintain the position of the teeth. Since the risk of recurrence is lifelong, the retention device should preferably be worn for life.

[0004] The retention device then has the function of providing sufficient rigidity to keep the teeth in position, while providing suitable flexibility so that the teeth retain freedom of movement relative to each other. Indeed, physiologically, the teeth have a certain natural mobility allowing them to absorb mechanical physical constraints by elasticity, in particular during chewing. The retention device must therefore allow controlled mobility between the teeth.

[0005] There are so-called removable retention devices, worn mainly at night. The effectiveness of removable devices depends on the patient's willingness and diligence, and frequent forgetfulness will affect their effectiveness.

[0006] There are also so-called fixed support devices, intended to be worn constantly by the patient, for a period of several months or even years, and requiring the intervention of a specialist for their installation and / or removal and / or repair.

[0007] Fixed retention devices are mainly intra-oral, and consist of fixing to the teeth, preferably on their non-visible lingual surface, a retention element having the required rigidity characteristics.

[0008] When the risks of recurrence are high, that is to say when the patient's dental mobility is high, the retention element may be a splint, in particular a metal one, for example cast and glued to the lingual surface of the teeth. The high rigidity of this solution may cause the metal splint to detach under the effect of chewing. In addition, irreversible mutilation of the teeth is necessary in order to provide space on the teeth corresponding to the thickness of the material forming the bar and limit discomfort in the mouth.

[0009] Another solution is to use a wire-type retention element, generally a braided multi-strand steel wire of circular cross-section, of a length suitable for providing retention on a given number of teeth. A specialist then shapes the wire, either directly on the lingual surface of the patient's teeth, or in the laboratory on a model of the patient's teeth, so that the wire is tightly pressed against the lingual surface of the teeth. The wire is then glued using composite resin pads to the teeth. The wire can be replaced by a metal chain, a rectangular cross-section wire, or a strip of glass fibers. Alternatively, the wire can be completely embedded in resin in order to be held against the teeth.

[0010] The thickness of the resin must allow the retention element to be coated, provide sufficient mechanical strength and limit discomfort in the mouth. Thus, the thickness of the resin influences to varying degrees the patient's comfort, the ease of cleaning and the risk of discomfort when chewing which can lead to detachment of the retention element and an emergency consultation with a specialist.

[0011] Furthermore, when the retention element is a wire, the complex bending thereof increases the risk that the wire does not perfectly follow the lingual surface of each tooth, as well as the boundary between two neighboring teeth. More precisely, the wire, locally rectilinear, may not follow the double convexity of the dental surfaces and creates a relief which is a source of discomfort for the patient and difficulty in cleaning.

[0012] Other techniques such as the cast splint or the fiber strip also have this increased disadvantage at the interdental limits, the surface area of ​​their section being greater than that of the wire.

[0013] Document WO2022 / 200246 proposes a retention device providing a solution in particular to the aforementioned drawbacks. In particular, it proposes a custom-made retention device making it possible to provide sufficient flexibility to the retention to allow the teeth the necessary freedom during chewing, while being sufficiently discreet to limit discomfort in the mouth for the patient. It also proposes a solution to assist the placement in the mouth of the retention device, in particular thanks to the implementation of a rigid connected assembly comprising guides for the retention element and guides for retaining elements, called plates, of the retention element.

[0014] Although this solution provides satisfaction in providing the patient with a retention device perfectly adapted to the configuration of the teeth, when the retention device must be repaired, it must be completely removed from the patient's mouth in order to reproduce the rigid connected assembly and to be able to replace the retention device in the patient's mouth with precision. For example, when the retention wire, welded to the entire set of plates, breaks, a complete retention device must be remanufactured, increasing costs. In addition, when a plate detaches from a tooth, it may remain in sufficient contact with the patient's tooth for the latter not to notice the defect. The resulting lack of retention may then remain unnoticed for a long enough time to cause poor alignment of the teeth. Finally, placement in the mouth guided by the rigid connected assembly may lack precision. Indeed, the greater the number of teeth affected by the retention, the greater the length of the rigid connected assembly, and the less precision the guidance for positioning the plates. Similarly, the greater the length of the rigid connected assembly, the more difficult it is to custom-make the wire.

[0015] The invention thus aims to provide a solution in particular to the aforementioned drawbacks.

[0016] A first aspect of the invention is to propose a fixed retainer for a patient which is easy to put in place on the patient's teeth and easy to repair.

[0017] A second aspect of the invention is to provide a fixed retainer that can be placed in a patient's mouth with increased precision.

[0018] A third aspect of the invention is to propose a fixed restraint whose costs remain limited.

[0019] A fourth aspect of the invention is to propose a fixed restraint which limits the risks of having a defect going unnoticed.

[0020] A fifth aspect of the invention is to provide a fixed retainer which provides sufficient comfort in the mouth for the patient.

[0021] A sixth aspect of the invention is to propose a fixed retainer that is easy to put in place on the patient's teeth by a practitioner. Summary of the invention

[0022] Thus, according to a first aspect, the invention relates to an orthodontic retention device intended to extend over at least {2+N} teeth to be treated in a patient's dentition. N is a natural number greater than or equal to 1. The device comprises in particular rigid plates and at least one connecting element rigidly fixed to the plates. Each plate comprises an internal rigid fixing surface on one face of a tooth in the patient's dentition and an opposite external surface comprising a place for fixing the connecting element. The device is particular in particular because it comprises at least {2+2N} plates to cover the {2+N} teeth to be treated, namely two so-called end plates and at least two so-called intermediate plates.In addition, said at least two intermediate plates are configured to be rigidly fixed on the same face of the same tooth of the patient, and form a pair of intermediate plates between the two end plates.

[0023] The device thus comprising pairs of plates has many advantages. In particular, it is easier to produce precisely, to install on the patient's teeth and with increased precision, for greater comfort for the patient. Its repair is made easier. Detachment problems are detected more quickly, avoiding a lack of retention which would go unnoticed and which would prevent the desired alignment of the patient's teeth from being obtained.

[0024] According to different aspects, it is possible to provide one and / or the other of the characteristics below taken alone or in combination.

[0025] According to one embodiment, the connecting element comprises a single section fixed to the attachment location of each plate. Thus, a single part forming the connecting element is handled and stored. Alternatively, the connecting element may comprise at least two separate sections, namely a first section fixed on the one hand to a first end plate and on the other hand to a first intermediate plate, and a second section fixed on the one hand to the second end plate and on the other hand to a second intermediate plate, further facilitating the precise installation of the device on the teeth of a patient.

[0026] According to one embodiment, the device is devoid of a connecting element section between two intermediate plates of the same pair, so that the device is presented in separate pieces which can for example be installed, removed, repaired by handling each piece independently of the other pieces. Handling is facilitated.

[0027] According to one embodiment, the device may comprise a plurality of pairs of intermediate plates between the two end plates, each intermediate plate of a pair being connected either to an intermediate plate of another pair or to an end plate by the connecting element.

[0028] According to one embodiment, the connecting element is welded to the attachment location of each plate. This may involve cold welding, for example by magnetic pulse, limiting or even avoiding the risk of increasing the temperature of the connecting element, such an increase being able to degrade the properties of the connecting element and ultimately the support provided by the device. It may also involve spot welding, localizing the temperature increase at the point of contact between the connecting element and the plate.

[0029] A second object of the invention is to propose an assistance system for the installation of a restraint device as presented above. The assistance system comprises in particular: • at least four plates, namely two so-called end plates and two so-called intermediate plates, each plate comprising an internal rigid fixing surface on one face of a tooth of the patient's dentition and an opposite external surface comprising a fixing location for at least one connecting element. Said at least two intermediate plates are then configured to be rigidly fixed on the same face of the same tooth of the patient, and form a pair of intermediate plates between the two end plates; • at least two guide assemblies for the individual positioning of said inserts. The two guide assemblies are physically distinct from one another. Each guide assembly is configured to guide the placement of at least two inserts, at least one insert of which is an intermediate insert. Each guide assembly further comprises at least one complementary guide for at least a portion of a face of at least one corresponding tooth, the guide being capable of being applied against the corresponding tooth in order to guide the inserts into a determined position on the teeth concerned. In addition, each guide assembly comprises at least one connection device between the two inserts.

[0030] Each guide assembly and the two pads it guides form a connected assembly, and each guide assembly is intended to be removed once the pads are rigidly fixed to the patient's teeth. Thus, each guide assembly can concentrate the guidance on two teeth only, limiting the size of the reference surface so as to maintain high guidance accuracy and therefore the placement of the pads on the patient's teeth. Installation is facilitated, and patient comfort is increased.

[0031] According to one embodiment, at least one connected assembly comprises at least one guide surface for the connecting element extending between the two plates. The guide surface for the connecting element is intended to be removed before placement in the mouth on the patient. Thus, the precise shaping of the connecting element is facilitated.

[0032] According to one embodiment, the guide assembly of at least one connected assembly comprises at least one first interlocking surface and at least one plate of said connected assembly comprises a second interlocking surface complementary to the first interlocking surface. In this way, said plate is positioned precisely on a face of a tooth of a patient by complementarity of the first interlocking surface with the second interlocking surface.

[0033] According to one embodiment, for at least one connected assembly, the connection device of the guide assembly is merged with the guide.

[0034] According to one embodiment, for at least one connected assembly, the connection device of the guide assembly comprises a connection arm, said arm being distinct from the guide and extending between the two plates of the connected assembly. This avoids having to act on the guide, for example by breaking the connection between the guide and the inserts, so as to limit the risks of damaging the guide and losing positioning precision. In addition, the guide and the inserts can then be produced separately, in different materials, reducing manufacturing costs and increasing the possible properties to choose for the guide.

[0035] According to one embodiment, for at least one connected assembly, the material arm comprises a first portion extending from a first plate of said connected assembly to a free edge and a second portion extending from a second plate of said connected assembly to a free edge. The first portion of the arm and the second portion of the arm come into contact with each other by their free edge. A locking system is then provided for locking the free edge of the first portion with the free edge of the second portion. Brief description of the drawings

[0036] Embodiments of the invention will be described below with reference to the drawings, briefly described below:

[0037] [Fig-1] represents a top view of a lower jaw of a human patient;

[0038] [Fig.2] is a diagram representing a restraint device according to one embodiment of the invention.

[0039] [Fig.3] represents a diagram of a first embodiment of a system for assisting in the placement of a restraint device according to the invention, the system comprising a plurality of connected assemblies.

[0040] [Fig.4] represents a first connected set of [Fig.3] seen along an external surface.

[0041] [Fig.5] represents the first connected set of [Fig.4] seen along an internal surface.

[0042] [Fig.6] represents the first connected assembly of [Fig.4] seen along a guide surface of a guide.

[0043] [Fig.7] represents a second connected assembly of [Fig.3] seen along an external surface.

[0044] [Fig.8] represents a third connected assembly of [Fig.3] seen along an external surface.

[0045] [Fig.9] represents another embodiment of a connected assembly seen along an external surface.

[0046] [Fig. 10] shows a related assembly similar to that of [Fig.9], in which the plates are provided with grooves.

[0047] [Fig. 11] schematically represents a restraint device according to the invention obtained from a connected assembly according to [Fig. 10].

[0048] [Fig. 12] is a diagram illustrating the transport of a wafer on a support.

[0049] In the drawings, like references designate identical or similar objects. DETAILED DESCRIPTION

[0050] In [Fig. 1], a lower jaw 100 of a human patient is shown, intended to receive an orthodontic retention device 1 according to the invention on at least part of the teeth 101. Preferably, the retention device 1 is of the fixed type, that is to say that it is intended to remain in place in the patient's mouth continuously and permanently. In the following, the device will be described with reference to the example of the lower jaw of [Fig.l], it being understood that the device 1 can be applied in the same way to the teeth of an upper jaw.

[0051] Each jaw 100 supports a set of teeth comprising at least one tooth 101. Each tooth 101 comprises a so-called lingual face 101a, i.e. facing towards the inside of the mouth and the tongue, a so-called labial face 101b, i.e. facing towards the outside of the mouth and the lips or cheeks, a top face 101c, i.e. facing towards the other jaw, in this case the upper jaw according to the example of [Fig.l], and two lateral edges 101c. Each lateral edge 101d of a tooth 101 may be in contact with, or face, a lateral edge 101d of an adjacent tooth, with the exception of a lateral edge 101d of the back teeth 101, i.e. the second or third molars, which is free.

[0052] More preferably, the retention device 1 is intended to be fixed on the lingual face 101a of the teeth, for reasons of discretion and aesthetics.

[0053] In [Fig.2], an example embodiment of the retention device 1 is shown schematically. The retention device 1 extends over at least three teeth, preferably three adjacent and successive teeth 101 on a patient's set of teeth. The device comprises rigid plates 2. By rigid, it is meant here that the plates do not deform under normal conditions of use: under the effect of the stresses undergone during the use of the retention device 1 placed in the mouth, under normal conditions of use, they do not deform.

[0054] Preferably, the rigid plates are made of metal or a metal alloy compatible with placement in the mouth. Other materials such as ceramic, or more generally any material used in orthodontics, may however be suitable.

[0055] The retention device 1 then comprises four rigid plates 2 for treating three teeth 101, that is to say that a tooth carries two plates 2. More generally, to treat a number (2+N) of teeth 101, where N is greater than or equal to one, the retention device 1 comprises a plate 2 called an end plate on each of the two teeth 101 at the end of the retention to be carried out, and two plates 101 called in intermediate, forming a pair, on each of the other teeth to be treated. Thus, in other words, for (2+N) teeth to be treated by the device 1, the retention device 1 comprises at least (2+2N) plates including N pairs of intermediate plates.

[0056] Thus, according to the diagram of [Fig.2], to treat three teeth 101, the retention device 1 comprises at least four rigid plates 2 to exert retention on three teeth: two end plates 2 and a pair of intermediate plates 2.

[0057] The plates 2 are fixed on the lingual face 101a or labial face 101b of the teeth 101 to be treated. More precisely, each plate 2 comprises an internal surface 3 for fixing on a face 101a or 101b of a tooth 101, that is to say intended to come into contact with the face 101a or 101b of the tooth 101 and providing a rigid fixing. The fixing can be carried out in particular by gluing, using an adhesive compatible with an orthodontic application. The internal surface 3 can optionally have micro-patterns to promote the retention of the adhesive. Each plate 2 further comprises an external surface 4, opposite the internal surface 3, which comprises a fixing location 5 for a connecting element 6.The outer surface 4 is preferably smooth before the attachment of the connecting element 6, that is to say it does not have any roughness detectable by the patient once the wafer 2 is placed in the mouth, in particular using the tongue, in order to limit discomfort in the mouth and the risks of injury. However, a marking of the location 5 of attachment of the connecting element 6 can be made on the outer surface 4, for example by a micro-marking which can be in slight negative or positive relief on the outer surface 4. The thickness of each wafer 2, that is to say the average distance between the inner surface 3 and the outer surface 4, is as small as possible, and corresponds for example to the smallest possible thickness to obtain the required rigidity, called the strength thickness of the material.The use of metal or metal alloy makes it possible to achieve very low resistance thicknesses compared to most other materials traditionally used in orthodontics, such as ceramic or resins.

[0058] The plates 2 can be individually sized and shaped to measure from a model of the patient's jaw 100 and his teeth, for example using CAD (Computer Aided Design) software and then by 3D printing. For example, the position, shape and dimensions of each plate 2 can be optimized using a model of the two jaws, lower and upper, of a patient, taking into account in particular the distance from the gum and the points of contact between the teeth during chewing. The dimensions and shape of the plates 2 can also be standard, with for example several standards depending on the teeth concerned and / or the tooth 101 on which the plate 2 is intended to be fixed and / or of the patient concerned. Platelets 2 can also come in a single format and can be cut by a technician according to needs. Here again, the use of metal or a metal alloy to manufacture platelets 2 allows good control of their geometry, so that it can be optimized.

[0059] The intermediate plates 2 intended to be fixed to the same tooth 101 may have substantially complementary shapes, so as to minimize the space taken up on the patient's tooth 101.

[0060] The connecting element 6 is fixed to the attachment location 5 of each plate 2 by any means compatible with placement in the mouth. Preferably, the attachment is carried out by welding or brazing, outside the patient's mouth. Welding ensures a good quality rigid attachment, with high mechanical strength and limits discomfort in the mouth. More preferably, the connecting element 6 is of the wire type, that is to say that it has a dimension called length which is very large compared to the other two, these being able to be very close or even identical. The connecting element 6 is for example a multi-strand metal wire, both sufficiently flexible to be shaped by a technician, for example using a tool, to adapt to the teeth to be treated and sufficiently rigid to provide the required support. The elastic properties of the connecting element 6 allow it to absorb chewing stresses and prevent the risk of fracture.

[0061] According to one embodiment, the welding of the connecting element 6 to the attachment location 5 of each plate 2 is carried out cold, and more precisely for example by the technique known as magnetic pulse welding. Such a technique makes it possible to limit the temperature rise inherent in hot welding techniques. Indeed, the temperature rise locally at the welding point propagates in the connecting element 6 and the metal plates 2. In particular, the heating of the connecting element 6 can degrade its elastic properties, and therefore the quality of the containment offered by the device 1. More precisely, magnetic field welding makes it possible to induce eddy currents in the connecting element 6, causing a Laplace force strongly pressing the connecting element 6 onto the plate 2 to the point of producing a weld, without the addition of heat.The mechanical and elastic properties of the connecting element 6 and the plates 2 are preserved. In order to facilitate correct positioning between the connecting element 6 and a plate 2, the plate 2 may comprise on its external face 4 a micro-groove passing through the fixing location 5. The micro-groove makes it possible in particular to position the connecting element 6 on the plate 2 and to hold it there during the cold welding operation.

[0062] According to another embodiment, the welding is carried out by spot welding, that is to say that the parts to be welded, in this case the connecting element 6 and a plate 2, are first brought into contact with each other at what is considered a contact point. Contact is maintained by exerting appropriate pressure to obtain an intimate contact point between the parts to be welded, ensuring a quality weld. Then, an electric current of controlled intensity (typically from a few amperes to a few tens of amperes) is sent to flow through the parts, and causes the materials to melt at the contact point. The fusion combined with the pressure ensures a high-quality weld, and allows the temperature rise to be localized at the contact point. The problems mentioned above regarding the temperature rise on the quality of the contention are again minimized, if not completely avoided.

[0063] Generally speaking, any welding or brazing technique making it possible to limit the temperature rise of the retention element 6 and / or the plates 2 may be suitable.

[0064] The connecting element 6 may be a single section fixed to the attachment location 5 of each plate 2, and extending continuously between the two end plates 2. Alternatively, and as illustrated in [Fig.2], the connecting element 6 may be formed from a plurality of sections 61, each section extending between two plates 2 of two successive adjacent teeth. The connecting element 6 may then be devoid of a section between two intermediate plates 2 of the same pair. Thus, according to the example in [Fig.2], the connecting element 6 comprises two sections 61: a first section 61 extends between a first end plate 102 and a first plate 2 of the intermediate pair of plates and a second section extends between the second plate 2 of the intermediate pair of plates and the second end plate 102.

[0065] The connecting element 6 can be custom-made, from the model of the patient's jaw 100 and his teeth and a model of the plates 2, for example using a CAD tool then by 3D printing. It can also be shaped by a technician using manual tools or automatically by a folding robot.

[0066] In practice, the retention device 1 may comprise a plurality of pairs of intermediate pads 2 between the two end pads 2, each intermediate pad 2 of a pair being connected either to an intermediate pad 2 of another pair or to an end pad 2 by the connecting element 6.

[0067] A set of teeth may carry several retention devices 1, for example when non-adjacent and successive teeth are affected by the retention.

[0068] The retention device 1 thus formed makes it easier to install it on the teeth 101 of a patient, but also makes it easier to repair it.

[0069] Indeed, concerning the installation, the restraint device 1 can be associated with a system 10 for assisting with installation. The assistance system 10 comprises for this purpose at at least four plates 2, namely two plates 2 called end plates and two plates 2 called intermediate plates, each plate 2 comprising an internal surface 3 for rigid attachment to the lingual face 101a or labial face 101b of a tooth 101 of the teeth of the jaw 100 of the patient and an opposite external surface 4 comprising a location 5 of attachment for at least one connecting element, typically wired. The at least four plates 2 are intended to be the plates 2 of the retention device 1 described above.

[0070] The assistance system 10 further comprises at least two guide assemblies 11 for the individual positioning of the inserts 2. The two guide assemblies 11 are physically distinct from one another, i.e. they can be manipulated independently of one another. Each guide assembly 11 is configured to guide the placement of at least two inserts 2, at least one insert 2 of which is an intermediate insert. In addition, each guide 11 comprises at least one guide 12, which provides guidance in the positioning of the inserts 2 on the teeth 101 by complementarity with at least one surface portion of at least one corresponding tooth 101. According to a particular example, the surface portion of the tooth 101 concerned comprises at least a part of the top face 101c of the tooth 101 in question.The guide 12 of each guide assembly 11 is then able to be applied against the corresponding tooth 101 in order to guide the at least two plates 2 into a determined position on the teeth concerned.

[0071] More precisely, according to the example illustrated in the figures, each guide assembly 11 makes it possible to guide the positioning of two plates 2 which are intended to be connected by the connecting element 6. In other words, each guide assembly 11 makes it possible to guide the positioning of an end plate 2 and an intermediate plate 2, or of two intermediate plates 2 of two distinct pairs. The guide 12 is then preferably complementary with a portion of the top face 101c of the two teeth 101 concerned by the two plates 2.

[0072] Each guide assembly 11 further comprises a connection device between the plates 2 which are concerned, that is to say that the plates 2 concerned are held in a relative position with respect to each other which is fixed.

[0073] The assistance system 10 is thus formed of at least two connected assemblies 10' which are physically independent of each other, i.e. they can be manipulated independently of each other. Each connected assembly 10' is formed of a guide 11 and at least the two plates 2 which it guides. Each connected assembly 10' is said to be rigid, because the connection device is more rigid than the connecting element 6. Thus, the connectivity, i.e. the rigid connection, between plates 2 obtained in a connected assembly 10' is preferably preserved at least until the connecting element 6 is fixed between the plates 2 of the same connected assembly 10'.

[0074] As will be explained later, the connectivity between two plates 2 within a connection assembly 10' may be permanent or temporary. By permanent, we mean here a connection which requires the definitive destruction of the connection element. By temporary, we mean here a connection which can be successively locked and unlocked.

[0075] To place the plates 2 on the patient's teeth 101, each connected set 10' is applied to the corresponding teeth, the guide 12 being placed in a complementary position on the teeth 101 by correspondence. The position of the plates 2 on the face, for example 101a, lingual of the teeth 101 is thus ensured with precision.

[0076] The guides 11 are intended to be removed once the plates 2 are rigidly fixed on the teeth 101 of the patient. The connectivity can be removed before, for example after the connecting element 6 has been fixed on the plates 2.

[0077] According to a first embodiment, the connection device of the guide assembly 11 of a connected assembly 10' is merged with the guide 12. More precisely, the guide 12 may comprise a strip 13 of material connecting it to each plate 2. The strip 13 of material ensures continuity of material between the plates 2. The two plates 2 of a connected assembly 10' are thus rigidly connected to each other by the connection element, which is formed by the guide 12 itself. The position in space of the two plates 2 relative to each other is thus maintained. Once the connecting element 6 is welded between the plates 2, the plates 2 are separated from the guide 12, for example by milling the strips 13 of material.Alternatively, the strip 13 is preferably formed so as not to be in contact with the teeth 101 when the guide 12 is in contact with the teeth 101, so as to allow the introduction of a cutting tool between the strips 13 and the teeth to cut the strip 13 once the plates 2 are fixed on the teeth 101.

[0078] Thus, the practitioner receives the system 10 for assisting with placement in the form of a plurality of connected sets 10'. Each connected set 10' is placed in the mouth, the plates 2, the position of which is guided by the guides 12, are fixed to the teeth 101, then the bands 13 are cut. The guide 11 and what remains of the bands 13 are removed from the mouth, leaving the plates 2 in place. Figures 4 to 8 show three different connected sets 10' intended to form a system 10 for assisting with the placement of four plates 2, namely: • A first connected set 10' comprising two intermediate plates 2, each intermediate plate 2 being part of a different pair (figures 4 to 6); • A second related assembly 10' comprising a first end plate 2 and a first intermediate plate 2 ([Fig.7]); • A third related set 10' comprising a second plate 2 end and a second intermediate plate 2 ([Fig.8]).

[0079] According to a second embodiment, the connection device is, as in the first embodiment, merged with the guide 12. However, it is not desirable to introduce a tool into the patient's mouth to remove the connectivity between the plates 2 of a connected assembly 10'. Therefore, the guide assembly 11 of a connected assembly 10' may comprise a fitting system between the guide 12 and the plates 2 of the connected assembly 10'. For this purpose, for example, before placing the aid device 10 in the mouth, the plates 2 of a connected assembly 10' are separated from the guide 12 by cutting, for example at the level of the band 13, before placing the retention device 1 in the mouth.The cutting between the inserts 2 and the guide 12 of a related set 10' creates the interlocking system: the cutting edges of the inserts maintain a complementarity with the cutting edges of the guide 12, along the cutting line, so as to allow the precise interlocking of the inserts 2 on the guide 12 after cutting. More precisely, the cutting line involves the formation of a first interlocking surface on the guide 12 and a second interlocking surface on each insert 2 of the related set 10'. Thus, before the placement assistance system 10 is placed in the mouth, the inserts 2 are separated from the guides 12 by cutting. The guides 12 are placed in the mouth in correspondence with the teeth 101 concerned. Then, the plates 2 are placed one by one on the teeth 101 while being guided by the complementarity with the guides 12 along the cutting edges, thanks to the interlocking surfaces.Once the plates 2 are fixed on the teeth 101, the guides 11 can simply be removed from the mouth, the plates 2 remaining in place.

[0080] According to a third embodiment, in order to avoid having to produce the cutting line of the second embodiment which could damage the guide 12 and cause inaccuracy in the positioning of the plates 2, the guide 12 and the plates 2 of a related assembly 10' are manufactured separately, that is to say as physically distinct parts, while retaining a fitting system 16, obtained for example by 3D printing by manufacturing complementary edges between the plates 2 and the guide 12. The connection element between the plates 2 of a related assembly 10' is then produced by a connection arm 17 extending between the two plates 2.More specifically, the connecting arm 17 is distinct from the guide 12, and comprises a first portion 18 extending from a first plate 2 of the related assembly 10' and comprises a second portion 19 extending from the second plate 2 of the related assembly 10' to join the first portion 18. For example, considering that the guide 12 extends from a first side of the plates 2, the portions 18, 19 of the arm 17 extend from a second side of the plate 2 substantially opposite the first side. According to the third embodiment, the first . portion 18 and the second portion 19 of the connecting arm 17 are made of one piece, that is to say in a single piece. To remove the connecting arm 17, for example after the connecting element 6 has been welded onto the plates 2, the two portions 18 and 19 of the arm 17 are separated for example by milling. Then the first portion 18 is separated from the first plate 2 by holding the first plate 2 using a pliers-type tool, and likewise the second portion 19 is separated from the second plate 2 by holding the second plate 2 using a pliers-type tool. The risk of damaging the guide 12 by cutting it to separate it from the plates 2 is thus avoided.

[0081] According to a fourth embodiment, the connection element comprises a locking system 20, making it possible to lock and unlock the connection between the plates 2 of a connected assembly 10'. For example, the connected assembly 10' is similar to that of the third embodiment, but the first portion 18 and the second portion 19 of the connection arm 17 are not monobloc. More precisely, the first portion 18 extends from the first plate 2 to a free edge 18a; likewise the second portion 19 extends from the second plate 2 to a free edge 19a. The locking system 20 then comprises a first part formed on the free edge 18a of the first portion 18 and a second part formed on the free edge 19a of the second portion 19, the two parts of the locking system 20 having complementary shapes ensuring total locking, that is to say in all directions.The complementary shapes are for example teeth. Thus, to fix the connecting element 6 on two plates 2 of a connected assembly 10', the two portions 18, 19 of the arm 17 are locked relative to each other by means of the locking system 20, and the locking is maintained while the fixing is carried out, for example using clamps which each hold a plate 2 of the connected assembly 10'. Once the fixing of the connecting element 6 on the plates 2 has been carried out, the two portions 18 and 19 are unlocked by separating them, then they are separated by milling or cutting the plates 2 as previously in the third embodiment.

[0082] Thus, the connectivity between two plates 2 within a connected assembly 10' can be obtained by continuity of material, that is to say by producing a continuous strip of material between the two plates 2, as in the first, second and third embodiments. The connectivity can also be obtained by relative positioning, as in the fourth embodiment, that is to say there is no continuity of material between the plates, but a locking of their relative position at least during the fixing of the connecting element 6 thanks to the locking system 20.

[0083] According to the second, third and fourth embodiments, the guides 12 and the plates 2 can be produced separately. It is then possible to manufacture the guides 12 in a material different from that of the plates 2, for example in plastic or resin, less expensive than metal.

[0084] According to the third and fourth embodiments, the guide 12 of a related assembly 10' may comprise as many separate portions as there are inserts 2 in the related assembly 10'. Thus, when the related assembly 10' comprises two inserts 2, the guide 12 may comprise two separate portions, each portion being complementary to a surface portion of a single tooth. By further reducing the dimensions necessary for complementarity to achieve guidance, the precision is further increased.

[0085] According to the third and fourth embodiments, the two portions 18, 19 of the connecting arm 17 are made so as to be coplanar. Thus, a check of their coplanarity makes it possible to ensure that the plates 2 to which the arm 17 is attached are correctly positioned relative to each other before fixing the connecting element 6.

[0086] The use of such a system 10 for assisting with placement is not mandatory. Any other means for placing the pads is conceivable. For example, when the pads are custom-made, the internal surface 3 of the pads 2 may be sufficiently complementary to a portion of the lingual face 101a, or labial face 101b, of the corresponding tooth 101 to ensure the correct positioning of the pad 2.

[0087] According to one embodiment, the positioning aid device 10 can also assist in shaping the connecting element 6. More specifically, each connected assembly 10' can comprise a guide surface 14 for the connecting element 6, between the two plates 2 of the connected assembly 10'. The guide surface 14 is for example formed on a tab 15 of material, integral with the guide 12. When the connected assembly 10' is in accordance with the third or fourth embodiment, the tab of material can be integral with the connecting arm 17. The tab 15 and the guide surface 14 are made for example to measure from a model of the patient's jaw 100 and his teeth, using a CAD tool and then by 3D printing or by molding.

[0088] The guide surface 14 makes it possible to shape the connecting element 6 between two plates 2 of the same connected set 10' of the aid system 10, outside the patient's mouth. The guide surface 14 extends into the corresponding volume between two teeth 101. It is therefore intended to be removed from the aid system 10 before placing in the mouth. Thus, once the connecting element 6 has been shaped to take the shape adapted to the patient's teeth and fixed to the places 5 where the plates 2 are fixed, the tab 15 is cut and removed from the aid system 10. Once placed in the mouth with the plates 2, the connecting element 6 is then in intimate contact with the face 101a lingual, or 101 labial, teeth 101, limiting discomfort for the patient.

[0089] It is then particularly advantageous to use a connecting element 6 formed from a plurality of sections 61, so that each section 61 is shaped and fixed to a connected assembly 10' of the aid system 10, leaving each assembly 10' independent of each other to allow each connected assembly 10' to be placed in the mouth one by one. However, the use of a connecting element 6 in the form of a single continuous section fixed to plates 2 of several connected assemblies 10' is entirely possible, since the connection then formed by the connecting element 6 between two plates 2 of two successive connected assemblies 10' has no effect on the retention.

[0090] The installation assistance system 10 thus simplifies the installation of the restraint device 1, while providing increased guidance precision.

[0091] Indeed, to install the retention device 1, the assistance system 10 is provided to the practitioner in the form of a plurality of connected assemblies 10' which are intended to be placed in an identified order on the teeth 101 of a patient's dentition. The connecting element 6 may already be fixed on the plates 2, in which case the guide surfaces 14 have been previously eliminated, or its shaping and fixing on the plates may be left to the practitioner, in which case the guide surfaces 14 may still be present when the system 10 is provided to the practitioner. Alternatively, the practitioner may not use a guide surface 14, and shape the connecting element 6 directly on the patient's teeth 101.

[0092] As already indicated previously, the connecting element 6 can be guided by the plates 2 themselves. Such guidance is particularly advantageous when the face 101a on which a plate 2 is to be fixed is small, so that the available space is insufficient to place the guide surface 14 of the connecting element 6. According to one embodiment, the guidance is achieved by means of a groove 21 on the external surface 4 of each plate 2. Thus, the connecting element 6 is pressed as close as possible to the external surface 4 of the plates 2 to which it is fixed.In order to prevent the thickness of the plates 2 from inducing a marked and uncomfortable radius of curvature for the patient on the connecting element 6 at the level of the change in level between the external surface 4 of the plate 2 and the tooth, the groove 21 may have a slope in the thickness of the plate 2, that is to say that the thickness of the plate in the groove 21 decreases to zero at the level of a free edge 2a of the plate 2. Thus, for example, the groove 21 comprises a non-through portion 21a on the plate 2 and a through portion 21b opening onto the free edge 2a of the plate 2. The groove 21 thus makes it possible both to guide the connecting element 6 between two plates 2 of a connected set 10' while increasing comfort in the mouth.

[0093] In any case, the system 10 for assisting with placement, without the surfaces 14 for guiding the connecting element 6, is then placed in the mouth by positioning each set 10' individually on the teeth 101. More specifically, each related set 10' is placed by correspondence of the guide 12 on the corresponding teeth 101. The plates 2 are rigidly fixed on the teeth, then the guides are removed from the mouth. In the event that the connecting element 6 has not already been shaped and fixed on the plates 2, the connecting element 6 is then shaped and / or fixed on the plates 2 directly in the patient's mouth.

[0094] By thus dividing the assistance system 10 into a plurality of connected sets 10', it is no longer necessary to have a single guide which extends continuously over all of the teeth 101 concerned by the retention: the guides 12, of reduced dimensions compared to a single guide, provide guidance for the placement with increased precision. It is also easier for the practitioner to manipulate a connected set 10' of reduced dimensions to guide the position of two plates 2 with precision.

[0095] The manufacture of the assistance system 10 in a plurality of connected assemblies 10' is also easier. Indeed, the smaller the surface area of ​​the guidel2 required for guidance, the fewer precautions need to be taken during manufacture to achieve high reliability.

[0096] Furthermore, in the case where an intervention on the retention device 1 is necessary, this is also facilitated. For example, it frequently happens that the connecting element 6 breaks between two teeth. On the devices of the prior art, in particular when the connecting element is welded onto the plates, it may then be necessary to remove the entire device from the mouth. It is then necessary either to repair the device by changing the connecting element and redoing the welds, or to completely manufacture a new retention device, then put everything back in the mouth. The costs can be significant, and by the time it takes to repair or manufacture a new device, the retention on the patient's teeth is no longer ensured. Thanks to the retention device 1 according to the invention, it is sufficient to remove the two plates 2 between which the connecting element 6 has broken.When the connecting element 6 is a single continuous section, it can be pre-cut so as to form a section including the break between two teeth. Thus, it is sufficient to remove two plates 2 and the broken section, the rest of the retention device 1 remaining in place in the patient's mouth. To replace two plates and a section 61 of the connecting element 6 in good condition, the practitioner can again use the system 10 for assisting with placement, using a related element 10'. Thus, not only are repair costs reduced, but in addition the absence of retention, while the broken section is being replaced, is localized to two teeth.

[0097] Finally, the retention device 1 can make it possible to detect the detachment of a wafer 2 more quickly. Indeed, in the case of the devices of the prior art, the detachment of a plate other than an end plate may go unnoticed, for example when it remains in sufficient contact with the tooth. A fairly long period may then pass before the patient detects the detachment, and during which the absence of retention causes poor alignment of the teeth. In the device 1 according to the invention, when an intermediate plate 2 detaches, it cannot remain in contact with the tooth, and then offers a protruding edge detectable by the patient immediately by the discomfort caused in the mouth. An intervention to reattach the plate 2 can then be implemented quickly, limiting the period without retention.

[0098] According to one embodiment, the guides 12 may be made of a material having elastic properties enabling it to act on the alignment of the teeth. By elastic properties, we mean here the ability of the guides to deform under the action of a force, and to return to their initial shape in the absence of force. For example, the guides 12 may be made of a titanium and nickel alloy. By using the complementarity with the teeth, the guides 12 may be fixed by any suitable means on the teeth 101 to act on the alignment of the teeth 101. The guides 12 may for example be used in this way when the retention device 1 is damaged, while it is being repaired or replaced.

[0099] According to one embodiment, the retention device 1 may be painted entirely or in part, for example by depositing electrostatic paint, in order to increase its discretion once in place on a patient's teeth. Alternatively, opacifying agents may be used, in particular resin-based, photo-polymerizable, and which may be applied with a brush to all or part of the device 1.

[0100] According to one embodiment, when the guide 12 is produced separately from the pads 2, and can therefore be made of a material other than metal, it can be made of a flexible and elastic material, for example plastic such as an acrylic resin, so as to be able to provide locking of the pads 2 by friction during transport. More precisely, during transport, the pads 2 can be placed on a support 22, generally a molding of the teeth of the patient concerned. In order to maintain the correct relative positioning between the pads 2, they must preferably be locked on the support 22. For this purpose, the guide 12 can comprise a portion 23 in the form of a cap which grips the support 22 and comprises a locking foot 24 which bears on the pad 2, at the level of the external surface 4 of the pad 2.The hat portion 23 is the portion which will complement the corresponding tooth portion to ensure guidance. The friction between the foot 24 and the external surface 4 of the plate 2, as well as the contact between the guide 12 and the plate 2 at the level of the interlocking system 16 guarantees that the plate 2 is held in place on the support 22.

[0101] According to one embodiment, during transport, the guides 12 physically separated from each other can be temporarily made integral when they are in place on the support 22, using a securing system, for example of the key type. The securing system is implemented during transport, then removed at the practitioner's. The stability of all the guides 12, and therefore of the plates 2, on the support 22, is thus ensured during transport.

Claims

Claims

1. Orthodontic retention device (1) intended to extend over at least {2+N} teeth (101) to be treated in a patient's dentition, with N greater than or equal to 1, the device (1) comprising rigid plates (2) and at least one connecting element (6) rigidly fixed to the plates (2), each plate (2) comprising an internal rigid fixing surface (3) on a face (101a, 101b) of a tooth (101) of the patient's dentition and an opposite external surface (4) comprising a place (5) for fixing the connecting element (6), the device (1) being characterized in that it comprises at least {2+2N} plates (2), namely two so-called end plates (2) and at least two so-called intermediate plates (2), and in that said at least two intermediate plates (2) are configured to be rigidly fixed on the same face (101a, 101b) of the same tooth (101) of the patient,and form a pair of intermediate plates (2) between the two end plates (2).

2. Device (1) according to claim 1, in which the connecting element (6) comprises a single section fixed to the location (5) of fixing of each plate (2).

3. Device (1) according to claim 1, in which the connecting element (6) comprises at least two separate sections (61), namely a first section (61) fixed on the one hand to a first end plate (2) and on the other hand to a first intermediate plate (2), and a second section (61) fixed on the one hand to the second end plate (2) and on the other hand to a second intermediate plate (2).

4. Device (1) according to the preceding claim, which is devoid of a section of connecting element (6) between two intermediate plates (2) of the same pair.

5. Device (1) according to any one of the preceding claims, comprising a plurality of pairs of intermediate plates (2) between the two end plates (2), each intermediate plate (2) of a pair being connected either to an intermediate plate (2) of another pair or to an end plate (2) by the connecting element (6).

6. Device (1) according to any one of the preceding claims, in which the connecting element (6) is welded to the location (5) of attachment of each plate (2).

7.

8. System (10) for assisting in the placement of a restraint device (1) according to any one of the preceding claims, the system (10) comprising: • at least four plates (2), namely two so-called end plates (2) and two so-called intermediate plates (2), each plate (2) comprising an internal surface (3) for rigid attachment to a face (101a, 101b) of a tooth (101) of the patient's teeth and an opposite external surface (4) comprising a location (5) for attachment to at least one connecting element (6), said at least two intermediate plates (2) being configured to be rigidly attached to the same face (101a, 101b) of the same tooth (101) of the patient, and form a pair of intermediate plates (2) between the two end plates (2); • at least two guide assemblies (11) for the individual positioning of said inserts (2), the two guide assemblies (11) being physically distinct from one another, each guide assembly (11) being configured to guide the placement of at least two inserts (2), of which at least one insert (2) is an intermediate insert (2), each guide assembly (11) comprising at least one guide (12) complementary to at least a portion of a face (101c) of at least one corresponding tooth (101), the guide (12) being capable of being applied against the corresponding tooth (101) in order to guide the inserts (2) into a determined position on the teeth (101) concerned, and each guide assembly (11) further comprising at least one connection device between the two inserts (2), each guide assembly (11) and the two plates (2) which it guides forming a connected assembly (10'), and each guide assembly (11) being intended to be removed once the plates (2) are rigidly fixed on the patient's teeth (101). Assistance system (10) according to the preceding claim, wherein at least one related assembly (10') comprises at least one guide surface (14) for the connecting element (6) extending between the two plates (2), the guide surface for the connecting element (6) being intended to be removed before placing in the mouth of the patient.

9. An aid system according to claim 7 or claim 8, wherein the guide assembly (11) of at least one related assembly (10') comprises at least one first interlocking surface and at least one plate (2) of said related assembly (10') comprises a second interlocking surface complementary to the first interlocking surface, so that said plate (2) is positioned on a face (101a, 101b) of a tooth (101) of a patient by complementarity of the first interlocking surface with the second interlocking surface.

10. Assistance system (10) according to any one of claims 7 to 9, wherein, for at least one related assembly (10'), the connection device of the guide assembly (11) is merged with the guide (12).

11. Assistance system (10) according to any one of claims 7 to 10, wherein, for at least one related assembly (10'), the connection device of the guide assembly (11) comprises a connection arm (17), said arm (17) being distinct from the guide (12) and extending between the two plates (2) of the related assembly (10').

12. Assistance system according to the preceding claim, wherein, for at least one connected assembly (10'), the connecting arm (17) comprises a first portion (18) extending from a first plate (2) of said connected assembly (10') to a free edge (18a) and a second portion (19) extending from a second plate (2) of said connected assembly (10') to a free edge (19a), and the first portion (18) of the arm (17) and the second portion (19) of the arm (17) coming into contact with each other by their free edge (18a, 19a), the assistance system (10) comprising a system (20) for locking the free edge (18a) of the first portion (18) with the free edge (19a) of the second portion (19).

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