Orthodontic retention device and aid system for placing 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) referred to as end plates and at least two plates (2) referred to as intermediate plates, and in that said at least two intermediate plates (2) are configured to be rigidly fixed 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). Figure for the abbreviation: Figure 2

Description

Title of the invention: Orthodontic retention device and aid system for placing such a device. FIELD OF THE INVENTION

[0001] The present invention relates to the field of orthodontics, and more specifically to the field of fixed, intraoral orthodontic retention systems intended to be applied, but not exclusively, to the lingual face of the teeth. technological BACKGROUND

[0002] After orthodontic treatment, aimed for example 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 then referred to as relapse.

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

[0004] The function of the retainer is to provide sufficient rigidity to hold the teeth in position, while also providing adequate flexibility so that the teeth retain freedom of movement relative to one another. Indeed, physiologically, teeth exhibit a certain degree of natural mobility that allows them to absorb mechanical stresses through elasticity, particularly during chewing. The retainer must therefore allow controlled movement between the teeth.

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

[0006] There are also so-called fixed restraint 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 placement and / or removal and / or repair.

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

[0008] When the risk of relapse is high, i.e., when the patient's tooth mobility is high, the retention element may be a splint, particularly a metallic one, for example, cast and bonded to the lingual surface of the teeth. The high rigidity of this solution can cause the metallic splint to detach under the effect of chewing. Furthermore, irreversible damage to the teeth is necessary in order to to create a space on the teeth corresponding to the thickness of the material forming the bar and to limit discomfort in the mouth.

[0009] Another solution involves using a wire-type retention element, generally a multi-strand braided steel wire with a circular cross-section, of a length suitable for retaining a specific number of teeth. A specialist then shapes the wire, either directly on the lingual surface of the patient's teeth or in a laboratory on a model of the patient's teeth, so that the wire fits snugly against the lingual surface. The wire is then bonded to the teeth using composite resin pads. The wire can be replaced by a metal chain, a rectangular wire, or a fiberglass strip. Alternatively, the wire can be completely embedded in resin to hold it against the teeth.

[0010] The thickness of the resin must be sufficient to encase the retainer, provide adequate mechanical support, and minimize discomfort in the mouth. Therefore, the resin thickness influences, to varying degrees, patient comfort, ease of cleaning, and the risk of chewing difficulties, which could lead to detachment of the retainer and the need for emergency consultation with a specialist.

[0011] Furthermore, when the retention element is a wire, its complex folding increases the risk that the wire will not perfectly follow the lingual surface of each tooth, as well as the boundary between two adjacent teeth. More specifically, the wire, being locally straight, may not follow the double convexity of the tooth surfaces and creates a relief that causes discomfort for the patient and makes cleaning difficult.

[0012] Other techniques such as cast splints or fiber strips also present this increased disadvantage at the interdental limits, the surface area of ​​their cross-section being greater than that of the wire.

[0013] Document WO2022 / 200246 proposes a retention device that addresses, in particular, the aforementioned drawbacks. Specifically, it proposes a custom-made retention device that provides sufficient flexibility to allow the teeth the necessary freedom of movement during chewing, while remaining discreet enough to minimize discomfort for the patient. It also proposes a solution to facilitate the placement of the retention device in the mouth, notably through the implementation of a rigid, connected assembly comprising guides for the retention element and guides for the retention elements, called retainers, of the retention element.

[0014] Although this solution is satisfactory in providing the patient with a retention device perfectly adapted to the configuration of the dentition, when the retention device needs to be repaired, it must be completely removed from the patient's mouth in order to reproduce the rigid associated assembly and to be able to precisely reposition the retention device in the patient's mouth. For example, when the If the retainer wire, welded to all the brackets, breaks, a complete retainer assembly must be fabricated, increasing costs. Furthermore, when a bracket detaches from a tooth, it may remain in contact with the patient's tooth long enough for the defect to go unnoticed. The resulting lack of retention can then remain undetected for a sufficient period to cause misalignment of the teeth. Finally, the placement in the mouth, guided by the rigid support assembly, can lack precision. Indeed, the greater the number of teeth involved in the retainer, the longer the rigid support assembly, and the less precise the guidance for positioning the brackets. Similarly, the longer the rigid support 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 offer a fixed retainer for a patient that is easy to place on the patient's teeth and easy to repair.

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

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

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

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

[0021] A sixth aspect of the invention is to provide 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 cover 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 surface for rigid attachment to one face of a tooth in the patient's dentition and an opposing external surface comprising a point for attaching the connecting element. The device is particular in that 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.Furthermore, said at least two intermediate plates are configured to be rigidly fixed to the same face of the same patient's tooth, and form a pair of intermediate plates between the two end plates.

[0023] The device, comprising pairs of retainers, offers numerous advantages. In particular, it is easier to manufacture precisely, to install on the patient's teeth with greater accuracy, and to provide improved patient comfort. Repair is also facilitated. Debonding problems are detected more quickly, preventing unnoticed lapses in retention that would hinder achieving the desired alignment of the patient's teeth.

[0024] Depending on different aspects, it is possible to foresee 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 at the attachment point of each plate. Thus, a single piece forming the connecting element is handled and stored. Alternatively, the connecting element may comprise at least two distinct sections, namely a first section fixed on one side to a first end plate and on the other side to a first intermediate plate, and a second section fixed on one side to the second end plate and on the other side to a second intermediate plate, further facilitating the precise placement of the device on a patient's teeth.

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

[0027] According to one embodiment, the device can 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 point where each pad is attached. This can be done by cold welding, for example by magnetic pulse welding, which limits or even eliminates the risk of increasing the temperature of the connecting element, as such an increase could degrade the properties of the connecting element and ultimately compromise the retention provided by the device. It can also be done by spot welding, which localizes the temperature increase to the point of contact between the connecting element and the pad.

[0029] A second object of the invention is to provide an assistance system for the application of a restraint device as described above. The assistance system includes, in particular: • at least four plates, namely two so-called end plates and two so-called intermediate plates, each plate comprising an internal surface for rigid fixation to one face of a tooth of the patient's dentition and an opposing external surface comprising a fixation point 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 patient's tooth, and form a pair of intermediate plates between the two end plates; • at least two guides for the individual positioning of the brackets. The two guides are physically separate from each other. Each guide is configured to guide the placement of at least two brackets, at least one of which is an intermediate bracket. Each guide also includes at least one additional reference surface of at least a portion of a face of at least one corresponding tooth, the reference surface being suitable for application against the corresponding tooth in order to guide the brackets into a predetermined position on the teeth concerned.

[0030] Each guide and the two plates it guides form a connected unit, and each guide is designed to be removed once the plates are rigidly fixed to the patient's teeth. Thus, each guide concentrates the guidance on only two teeth, limiting the size of the reference surface to maintain high precision in guiding and therefore in the placement of the plates on the patient's teeth. Installation is facilitated, and patient comfort is increased.

[0031] According to one embodiment, at least one connected assembly includes at least one guiding surface for the connecting element extending between the two plates. The guiding surface for the connecting element is intended to be removed before placement in the patient's mouth. This facilitates the precise shaping of the connecting element.

[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 precisely positioned on a face of a patient's tooth by the complementarity of the first interlocking surface with the second interlocking surface.

[0033] According to one embodiment, at least one connected assembly includes 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 to 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 set of [Fig.3] seen along an external surface.

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

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

[0044] Figure 1 shows the lower jaw 100 of a human patient, intended to receive an orthodontic retention device 1 according to the invention on at least some of the teeth 101. Preferably, the retention device 1 is of the fixed type, that is, it is intended to remain in place in the patient's mouth continuously and permanently. The device will be described below with reference to the example of the lower jaw in Figure 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 lingual face 101a, i.e., facing the inside of the mouth and the tongue, a labial face 101b, i.e., facing the outside of the mouth and the lips or cheeks, a cusp face 101c, i.e., facing the other jaw, in this case the upper jaw as illustrated in [Fig. 1], and two lateral edges 101. Each lateral edge 101 of a tooth 101 may be in contact with, or face, a lateral edge 101d of an adjacent tooth, with the exception of one lateral edge 101 of the back teeth 101, i.e., the second or third molars, which is free.

[0046] 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] Figure 2 schematically illustrates an example of an embodiment of the retention device 1. The retention device 1 extends over at least three teeth, preferably three adjacent and successive teeth 101 in a patient's dentition. 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 experienced during the use of the retention device 1 placed in the mouth, under normal conditions of use, they do not deform.

[0048] Preferably, rigid brackets are made of metal or a metal alloy compatible with oral insertion. However, other materials such as ceramic, or more generally any material used in orthodontics, may be suitable.

[0049] The retention device 1 then comprises four rigid plates 2 to treat three teeth 101, that is, each tooth has 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 one plate 2, called the end plate, on each of the two teeth 101 at the end of the retention to be achieved, and two plates 101, called the 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 in [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 one pair of intermediate plates 2.

[0051] The plates 2 are fixed to the lingual 101a or labial 101b surface of the teeth 101 to be treated. More specifically, each plate 2 comprises an internal fixation surface 3 for a surface 101a or 101b of a tooth 101, i.e., intended to come into contact with the surface 101a or 101b of the tooth 101 and provide rigid fixation. The fixation may be achieved, in particular, by bonding, using an adhesive compatible with orthodontic application. The internal surface 3 may optionally have micro-patterns to promote adhesive retention. Each plate 2 further comprises an external surface 4, opposite the internal surface 3, which includes a fixation site 5 for a connecting element 6.The outer surface 4 is preferably smooth before the attachment of the connecting element 6, meaning it has no asperities detectable by the patient once the plate 2 is placed in the mouth, particularly with the tongue, in order to limit discomfort in the mouth and the risk of injury. However, the attachment point 5 for the connecting element 6 can be marked on the outer surface 4, for example by a micro-marking that can be slightly raised, either negative or positive. The thickness of each plate 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 material's strength thickness. The use of metal or metal alloys makes it possible to achieve very small strength thicknesses compared to most other materials commonly used in orthodontics, such as ceramics or resins.

[0052] The plates 2 can be individually dimensioned and shaped to measure from a model of the patient's jaw 100 and dentition, 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 both jaws, upper and lower, of a patient, taking into account, in particular, the distance from the gum and the contact points between the teeth during mastication. The dimensions and shape of the plates 2 can also be standardized, with, for example, several standards depending on the dentition 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 in a single format that can be cut by a technician as needed.Here again, the use of metal or a metal alloy to manufacture the plates 2 allows for 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 bulk on the patient's tooth 101.

[0054] The connecting element 6 is fixed to the fixation point 5 of each plate 2 by any means compatible with oral placement. Preferably, the fixation is achieved by welding or brazing, outside the patient's mouth. Welding ensures a rigid, high-quality fixation with high mechanical strength and minimizes discomfort in the mouth. Even more preferably, the connecting element 6 is of the wire type, meaning that it has a dimension, called its length, that is much greater than the other two, which may be very close or even identical. The connecting element 6 is, for example, a multi-strand metal wire, both flexible enough to be shaped by a technician, for example using a tool, to adapt to the teeth being treated and rigid enough to provide the required retention. The elastic properties of the connecting element 6 allow it to absorb masticatory stresses and prevent the risk of fracture.

[0055] According to one embodiment, the welding of the connecting element 6 to the fixing point 5 of each plate 2 is carried out cold, and more specifically, for example, by the technique known as magnetic pulse welding. Such a technique makes it possible to Limiting the temperature rise inherent in hot welding techniques is crucial. Indeed, the localized temperature rise at the weld point propagates through the connecting element 6 and the metal plates 2. In particular, heating the connecting element 6 can degrade its elastic properties, thus compromising the quality of the clamping action provided by the device 1. More precisely, magnetic field welding induces eddy currents in the connecting element 6, generating a Laplace force that firmly presses the connecting element 6 against the plate 2, creating a weld without the need for additional heat. The mechanical and elastic properties of the connecting element 6 and the plates 2 are preserved. To facilitate proper positioning between the connecting element 6 and a plate 2, the plate 2 may have a micro-groove on its outer face 4 passing through the fixing point 5. The micro-groove allows the connecting element 6 to be positioned on the plate 2 and held in place during the cold welding operation.

[0056] According to another embodiment, the welding is performed by spot welding, meaning 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 point of contact. The contact is maintained by applying appropriate pressure to obtain an intimate point of contact between the parts to be welded, ensuring a high-quality weld.Then, a controlled-intensity electric current (typically from a few amps to a few tens of amps) is sent through the parts, causing the materials to melt at the point of contact. This melting, combined with the pressure, ensures a high-quality weld and allows the temperature rise to be localized to the point of contact. The problems mentioned above regarding temperature rise and the impact on weld quality are thus minimized, or even completely avoided.

[0057] In general, any welding or brazing technique that allows the temperature rise of ITelement 6 of containment and / or of the plates 2 will be suitable.

[0058] The connecting element 6 can be a single section fixed to the attachment point 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 can be formed of a plurality of sections 61, each section extending between two plates 2 of two successive adjacent teeth. The connecting element 6 can 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 plate pair, and a second section extends between the second plate 2 of the intermediate plate pair and the second end plate 102.

[0059] The connecting element 6 can be custom-made from a model of the patient's jaw 100 and dentures and a model of the plates 2, for example using a CAD tool and then by 3D printing. It can also be shaped by a technician using hand tools or automatically by a bending robot.

[0060] In practice, the restraint device 1 can include 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 dentition can support several retention devices 1, for example when non-adjacent and successive teeth are involved in retention.

[0062] The retention device 1 thus formed makes it easier to install on the teeth 101 of a patient, but also makes it easier to repair.

[0063] Indeed, with regard to installation, the retention device 1 can be associated with a placement aid system 10. The placement aid system 10 comprises, for this purpose, at least four plates 2, namely two end plates 2 and two intermediate plates 2, 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 patient's jaw 100 and an opposing external surface 4 comprising a point 5 for attachment to at least one connecting element, typically a wire. The at least four plates 2 are intended to be the plates 2 of the retention device 1 described above.

[0064] The aid system 10 further comprises at least two guides 11 for the individual positioning of the pads 2. The two guides 11 are physically separate from each other, i.e., they can be manipulated independently. Each guide 11 is configured to guide the placement of at least two pads 2, at least one of which is an intermediate pad. In addition, each guide 11 includes at least one complementary reference surface 12 of at least a portion of the surface of at least one corresponding tooth 101. In a particular example, the portion of the surface of the tooth 101 in question includes at least a part of the apex face 101c of the tooth 101 in question. The reference surface 12 of each guide 11 is then suitable for being applied against the corresponding tooth 101 in order to guide the at least two pads 2 into a predetermined position on the teeth concerned.

[0065] More specifically, according to the example illustrated in the figures, each guide 11 allows the positioning of two plates 2 which are intended to be connected by the connecting element 6. In other words, each 11 allows the positioning of an end plate 2 and an intermediate plate 2 to be guided, or of two intermediate plates 2 of two distinct pairs. The reference surface 12 then corresponds preferably to a portion of the summit face 101c of the two teeth 101 concerned by the two plates 2.

[0066] The aid system 10 is thus formed of at least two connected sets 10' that 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 pads 2 that 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 corresponding teeth 101. The position of the plates 2 on the lingual face, for example 101a, 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 to the patient's teeth 101.

[0069] More specifically, each plate 2 of a connected assembly 10' can be connected to the guide 11 by a strip 13 of material ensuring material continuity between the guide 11 and the plates 2. The two plates 2 of a connected assembly 10' are thus rigidly connected to each other by a connecting element, which is formed by the strips 13 and the guide 11 itself. The connecting 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 band 13 is preferably shaped 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 bands 13 and the teeth to sever the band 13 once the plates 2 are fixed to the teeth 101. Thus, the practitioner receives the placement aid system 10 in the form of a plurality of connected assemblies 10'. Each connected assembly 10' is placed in the mouth, the plates 2, whose position is guided by the reference surfaces 12, are fixed to the teeth 101, and then the bands 13 are cut. The guide 11 and what remains of the strips 13 are removed from the mouth, leaving the plates 2 in place. Figures 4 to 8 show three different connected assemblies 10' intended to form a system 10 for assisting in 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 connected set 10' comprising a first end plate 2 and a first intermediate plate 2 ([Fig.7]); • A third connected set 10' comprising a second end plate 2 and a second intermediate plate 2 ([Fig.8]).

[0071] To avoid having to insert a cutting tool into the mouth before inserting the support device 10, the plates 2 of a connected assembly 10' are separated from the guide 11 by cutting before the retention device 1 is inserted. The cutting between the plates 2 and the guide 11 creates a cutting line that maintains a complementary fit between the plates 2 and the guide 11, so as to allow the precise interlocking of the plates 2 onto the guide 11 after cutting. More specifically, each cutting line involves the formation of a first interlocking surface on the guide 11 and a second interlocking surface on the plate 2 concerned. Thus, before the placement of the support system 10, the plates 2 are separated from the guides 11 by cutting. The guides 11 are placed in the mouth by corresponding reference surfaces 12 with the relevant teeth 101.Then, the plates 2 are placed on the teeth 101, guided by their complementary position 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 simply be removed from the mouth, the plates 2 remaining in place.

[0072] The use of such a placement aid system 10 is not mandatory. Any other means of placing the brackets is conceivable. For example, when the brackets are custom-made, the internal surface 3 of the brackets 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 bracket 2.

[0073] According to one embodiment, the positioning aid 10 can also assist in shaping the connecting element 6. More specifically, each connected assembly 10' can include a guide surface 14 for the connecting element 6, located between the two plates 2 of the connected assembly 10'. The guide surface 14 is, for example, formed on a material tab 15, integral with the reference surface 12. The tab 15 and the guide surface 14 are, for example, custom-made from a model of the patient's jaw 100 and dentition, using a CAD tool and then by 3D printing or molding.

[0074] The guide surface 14 allows the connecting element 6 between two plates 2 of the same connected assembly 10' of the assistive system 10 to be shaped 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 assistive system 10 before insertion into the mouth. Thus, once the connecting element 6 has been shaped to fit the patient's dentition and fixed to the attachment points 5 of the plates 2, the tab 15 is cut out and removed from the assistive system 10. Once inserted into the mouth with the plates 2, the linking element 6 is then in intimate contact with the lingual face 101a, or labial face 101, 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, such that each section 61 is shaped and fixed to a connected assembly 10' of the support system 10, leaving each assembly 10' independent of the others to allow each connected assembly 10' to be inserted 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 perfectly 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 setup aid system 10 thus simplifies the installation of the restraint device 1, while offering increased guidance accuracy.

[0077] Indeed, to install the retention device 1, the support system 10 is provided to the practitioner in the form of a plurality of interconnected assemblies 10' intended to be placed in a specific order on the teeth 101 of a patient's dentition. The connecting element 6 may already be fixed to the plates 2, in which case the guide surfaces 14 have been previously removed, or its shaping and fixing to 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 may shape the connecting element 6 directly on the patient's teeth 101.

[0078] In any event, the placement aid system 10, lacking 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 aligning the reference surface 12 of the guide with the corresponding teeth 101. The plates 2 are rigidly fixed to the teeth, and then the guides are removed from the mouth. If the connecting element 6 has not already been shaped and fixed to the plates 2, the connecting element 6 is then shaped and / or fixed to the plates 2 directly in the patient's mouth.

[0079] By thus dividing the support system 10 into a plurality of interconnected sets 10', it is no longer necessary to have a single reference surface extending continuously over all the teeth 101 involved in the retention: the reference surfaces 12, smaller in size than a single reference surface, provide guidance for placement with increased precision. Furthermore, it is easier for the practitioner to manipulate a smaller interconnected set 10' to precisely guide the position of two brackets 2.

[0080] Manufacturing the aid system 10 in a plurality of connected sets 10' is also easier. Indeed, the smaller the reference surface 12, The less important the precautions taken during manufacturing to achieve high reliability, the better.

[0081] Furthermore, if 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 anterior appliances, particularly when the connecting element is welded to the plates, it may then be necessary to remove the entire appliance from the mouth. It is then necessary either to repair the appliance by replacing the connecting element and re-welding it, or to fabricate a completely new retention appliance and then reinstall it in the mouth. The costs can be significant, and while repairing or fabricating a new appliance, retention on the patient's dentition is no longer guaranteed. 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 to form a section encompassing the break between two teeth. Thus, it is sufficient to remove two plates 2 and the broken section, leaving the remainder of the retainer 1 in place in the patient's mouth. To reposition two plates and a section 61 of the connecting element 6 in good condition, the practitioner can again use the placement aid system 10, employing a related element 10'. In this way, not only are repair costs reduced, but the gap in retention while the broken section is being replaced is limited to just two teeth.

[0082] Finally, the retention device 1 can allow for faster detection of the detachment of a bracket 2. Indeed, in the case of anterior appliances, the detachment of a bracket other than an end bracket can go unnoticed, for example, when it remains sufficiently in contact with the tooth. A considerable period can then elapse before the patient detects the detachment, and during this time, the lack of retention leads to misalignment of the teeth. In the device 1 according to the invention, when an intermediate bracket 2 detaches, it cannot remain in contact with the tooth, and thus presents a protruding edge that is immediately detectable by the patient due to the discomfort it causes in the mouth. A procedure to reattach the bracket 2 can then be performed quickly, limiting the period without retention.

[0083] According to one embodiment, the guides 11 can be made of a material having elastic properties that allow it to act on the alignment of the teeth. Elastic properties here refer to the ability of the guides to deform under the action of a force and to return to their initial shape when no force is applied. For example, the guides 11 can be made of a titanium-nickel alloy. Using the reference surfaces 12, the guides 11 can be fixed by any means adapted on teeth 101 to act on the alignment of 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 retainer 1 can be painted entirely or partially, for example by electrostatic paint deposition, in order to increase its discreetness once in place on a patient's teeth. Alternatively, opacifying agents, particularly photopolymerizable resin-based agents, can be used and applied by 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 inserts (2), the two guides (11) being physically distinct from one another, each guide (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 (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 inserts (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 patient's mouth.

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 patient's teeth (101).

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