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 guides for individual positioning of the inserts. The two guides are physically distinct from one another. Each guide is configured to guide the placement of at least two inserts, at least one insert of which is an intermediate insert. Each guide further comprises at least one reference surface complementary to at least a portion of a face of at least one corresponding tooth, the reference surface being capable of being applied against the corresponding tooth in order to guide the inserts into a determined position on the teeth concerned.

[0030] Each guide and the two pads it guides form a connected assembly, and each guide is intended to be removed once the pads are rigidly fixed to the patient's teeth. Thus, each guide concentrates 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, precise shaping of the connecting element is facilitated.

[0032] According to one embodiment, the guide 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, at least one connected assembly comprises a connecting element extending between the at least two corresponding plates, the connecting element being intended to be removed once the plates are rigidly fixed on the patient's teeth. Brief description of the drawings

[0034] Embodiments of the invention will be described below with reference to the drawings, briefly described below:

[0035] [Fig-1] represents a top view of a lower jaw of a human patient;

[0036] [Fig.2] is a diagram representing a restraint device according to an embodiment of the invention.

[0037] [Fig.3] represents a diagram of an 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.

[0038] [Fig.4] represents a first connected set of [Fig.3] seen along an external surface.

[0039] [Fig.5] represents the first connected set of [Fig.4] seen along an internal surface.

[0040] [Fig.6] represents the first connected set of [Fig.4] seen along a reference surface.

[0041] [Fig.7] represents a second connected assembly of [Fig.3] seen along an external surface.

[0042] [Fig.8] represents a third connected assembly of [Fig.3] seen along an external surface.

[0043] In the drawings, like references designate identical or similar objects. DETAILED DESCRIPTION

[0044] 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. 1], it being understood that the device 1 can be applied in the same way to the teeth of an upper jaw.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] The retention device 1 then comprises four rigid plates 2 for treating three teeth 101, that is to say that one 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 intermediate plates, 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.

[0050] 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.

[0051] 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 external surface 4 is preferably smooth before the attachment of the connecting element 6, that is to say that it does not have any roughness detectable by the patient once the plate 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 external surface 4, for example by a micro-marking which can be in slight negative or positive relief on the external surface 4. The thickness of each plate 2, . that is to say the average distance between the internal surface 3 and the external surface 4, is the smallest possible, and corresponds for example to the smallest possible thickness to obtain the required rigidity, called the resistance 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.

[0052] 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 the patient concerned. The plates 2 can also be presented in a single format and which can be cut by a technician according to the needs.Here again, the use of metal or a metal alloy to manufacture the plates 2 allows good control of their geometry, so that it can be optimized.

[0053] 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.

[0054] 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 that 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.

[0055] According to one embodiment, the welding of the connecting element 6 to the location 5 of attachment 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, heating the connecting element 6 can degrade its elastic properties, and therefore the quality of the support provided 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 heat input. The mechanical and elastic properties of the connecting element 6 and the plates 2 are preserved. In order to facilitate the 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 maintain it there during the cold welding operation.

[0056] 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 to be a point of contact. The contact is maintained by exerting a pressure adapted to obtain an intimate point of contact between the parts to be welded, guaranteeing 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 point of contact. The fusion combined with the pressure ensures high-quality welding, and allows the temperature rise to be localized at the point of contact. The problems mentioned above regarding the temperature rise on the quality of the contention are again minimized, if not completely avoided.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] In practice, the retention device 1 may comprise 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.

[0061] A set of teeth may carry several retention devices 1, for example when non-adjacent and successive teeth are affected by the retention.

[0062] 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.

[0063] Indeed, concerning the installation, the retention device 1 can be associated with a system 10 for assisting with the installation. The assistance system 10 comprises for this purpose 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 place 5 for 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.

[0064] The assistance system 10 further comprises at least two guides 11 for the individual positioning of the inserts 2. The two guides 11 are physically distinct from one another, that is to say they can be manipulated independently of one another. Each guide 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 reference surface 12 complementary to 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 reference surface 12 of each guide 11 is then capable of being applied against the corresponding tooth 101 in order to guide the at least two inserts 2 into a determined position on the teeth concerned.

[0065] More precisely, according to the example illustrated in the figures, each guide 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 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 reference surface 12 then preferably corresponds to a portion of the top face 101c of the two teeth 101 concerned by the two plates 2.

[0066] The assistance system 10 is thus formed of at least two connected sets 10' which are physically independent of each other, i.e. they can be manipulated independently of each other. Each connected set 10' is formed of a guide 11 and at least the two plates 2 which it guides.

[0067] To place the plates 2 on the patient's teeth 101, each connected set 10' is applied to the corresponding teeth, the reference surface 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.

[0068] The guides 11 are intended to be removed once the plates 2 are rigidly fixed on the patient's teeth 101.

[0069] More precisely, each plate 2 of a connected set 10' can be connected to the guide 11 by a strip 13 of material ensuring continuity of material between the guide 11 and the plates 2. The two plates 2 of a connected set 10' are thus rigidly connected to each other by a connection element, which is formed by the strips 13 and the guide 11 itself. The connection element is said to be rigid because it is more rigid than the connecting element 6. The position in space of the two plates 2 relative to each other is thus maintained.

[0070] According to one embodiment, the strip 13 is preferably formed so as not to be in contact with the teeth 101 when the reference surface 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. 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 reference surfaces 12, are fixed on the teeth 101, then the strips 13 are cut. The guide 11 and what remains of the strips 13 are removed from the mouth, leaving the pads 2 in place. Figures 4 to 8 show three different connected sets 10' intended to form a system 10 for assisting in the placement of four pads 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 assembly 10' comprising a second end plate 2 and a second intermediate plate 2 ([Fig.8]).

[0071] In order to avoid having to introduce a cutting tool into the mouth, before placing the aid device 10 in the mouth, the plates 2 of a related set 10' are separated from the guide 11 by cutting before placing the retention device 1 in the mouth. The cutting between the plates 2 and the guides 11 creates a cutting line which maintains complementarity between the plates 2 and the guide 11, so as to allow the precise fitting of the plates 2 on the guide 11 after cutting. More precisely, each cutting line involves the formation of a first fitting surface on the guide 11 and a second fitting surface on the plate 2 concerned. Thus, before placing the placement aid system 10 in the mouth, the plates 2 are separated from the guides 11 by cutting. The guides 11 are placed in the mouth by correspondence of reference surfaces 12 with the teeth 101 concerned.Then, the plates 2 are placed on the teeth 101 while being guided by the complementarity with the guides 11 along the cutting lines, thanks to the interlocking surfaces. Once the plates 2 are fixed on the teeth 101, the guides 11 can be simply removed from the mouth, the plates 2 remaining in place.

[0072] The use of such a system 10 for assisting with placement is not obligatory. 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.

[0073] According to one embodiment, the device 10 for assisting with placement 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 tongue 15 of material, integral with the reference surface 12. The tongue 15 and the guide surface 14 are for example made 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.

[0074] The guide surface 14 makes it possible to shape the connecting element 6 between two plates 2 of the same connected assembly 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 placement 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 lingual face 101a, or 101 labial, of the teeth 101, limiting discomfort for the patient.

[0075] 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.

[0076] The installation assistance system 10 thus simplifies the installation of the restraint device 1, while providing increased guidance precision.

[0077] 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.

[0078] In any case, the positioning assistance system 10, devoid of the guide surfaces 14, is then placed in the mouth by positioning each assembly 10' individually on the teeth 101. More precisely, each connected assembly 10' is placed by correspondence of the reference surface 12 of the guide 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.

[0079] By thus dividing the assistance system 10 into a plurality of connected sets 10', it is no longer necessary to have a single reference surface which extends continuously over all of the teeth 101 concerned by the retention: the reference surfaces 12, of reduced dimensions compared to a single reference surface, provide guidance for the placement with increased precision. It is also easier for the practitioner to manipulate a connected set 10' of reduced dimension to guide the position of two plates 2 with precision.

[0080] The manufacture of the aid system 10 in a plurality of connected assemblies 10' is also easier. Indeed, the smaller the reference surface 12, the fewer precautions that need to be taken during manufacturing to achieve high reliability.

[0081] 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.

[0082] 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 wafer other than an end wafer can go unnoticed, for example when it remains in sufficient contact with the tooth. A fairly long period can 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 wafer 2 detaches, it cannot remain in contact against 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 wafer 2 can then be implemented quickly, limiting the period without retention.

[0083] According to one embodiment, the guides 11 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 capacity 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 11 may be made of a titanium and nickel alloy. By using the reference surfaces 12, the guides 11 may be fixed by any means adapted to the teeth 101 to act on the alignment of the teeth 101. The guides 11 can for example be used in this way when the retention device 1 is damaged, while it is being repaired or replaced.

[0084] 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.

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 or claim 2, 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 fixing location (5). of each plate (2).

7. 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 guides (11) for the individual positioning of the pads (2), the two guides (11) being physically distinct from one another, each guide (11) being configured to guide the placement of at least two pads (2), of which at least one pad (2) is an intermediate pad (2), each guide (11) further comprising at least one reference surface (12) complementary to at least one portion of a face (101c) of at least one corresponding tooth (101), the reference surface (12) being capable of being applied against the corresponding tooth (101) in order to guide the pads (2) into a determined position on the teeth (101) concerned, each guide (11) and the two plates (2) which it guides forming a connected assembly (10'), and each guide (11) being intended to be removed once the plates (2) are rigidly fixed on the patient's teeth (101).

8. Assistance system (10) according to the preceding claim, in which 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 placement in the mouth on the patient.

9. An aid system according to claim 7 or claim 8, wherein the guide (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. An aid system (10) according to any one of claims 7 to 9, wherein at least one related assembly (10') comprises a connecting element (11, 13) extending between the at least two corresponding plates (2), the connecting element (11, 13) being intended to be removed once the plates (2) are rigidly fixed on the teeth (101) of the patient.

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