Pad for a restraint device, restraint device comprising such a pad, and method for manufacturing such a restraint device

Abstract

A plate (4) intended to be rigidly fixed to a retention element (6) of a retention device (1), said plate (4) comprising an inner face (2) intended to be rigidly fixed to a face (101a, 101b) of a patient's tooth (101), an opposing outer face (3), and a lateral edge (5) forming the junction between the inner face (2) and the outer face (3), the inner face (2) being shaped in part to correspond to at least a portion of the relevant face (101a, 101b) of the tooth (101), the plate (4) further comprising at least one notch (7) on the inner face (2), the notch (7) comprising an opening (7a) leading to the lateral edge (5) of the plate so as to allow the insertion of a tool (20) into the notch (7) when the inner face (2) of the Plate (4) is fixed to the tooth (101). Figure for the abbreviation: figure 2

Description

Title of the invention: Pad for a restraint device, restraint device comprising such a pad, and method for manufacturing such a restraint device. SCOPE OF THE INVENTION

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

[0002] More specifically, the invention relates to a plate of an orthodontic retention device.... technological BACKGROUND

[0003] Following 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.

[0004] 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.

[0005] 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.

[0006] 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.

[0007] 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.

[0008] 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.

[0009] 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 tooth mutilation is necessary to create a space on the teeth corresponding to the thickness of the material forming the bar and to limit discomfort in the mouth.

[0010] 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.

[0011] The resin thickness must be sufficient to encase the retention element, 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 retention element and the need for emergency consultation with a specialist.

[0012] Document FR3005405 describes a passive fixed retention device comprising a support onto which metal brackets, called copings, are fixed. More specifically, the brackets have a groove forming a recess, and the support, which is typically a wire, is fixed inside the recesses. The support is fixed in the bracket recesses by bonding. The brackets are bonded to the teeth so as to hold the wire while remaining as close as possible to the tooth.

[0013] Such a retention device makes it possible to increase comfort in the mouth, in particular thanks to the plates, while providing effective and comfortable retention thanks to the retention wire held against the teeth.

[0014] However, it frequently happens that the wire is damaged or even breaks. Repair of the retainer must be carried out by a professional practitioner and involves removing at least one retainer from the patient's mouth, or even all of them. Removing a retainer is a delicate operation: the aim is for the retainer to be as close as possible to the tooth for the patient's comfort, with no gap between the retainer and the tooth to prevent food from getting stuck. The tool used to remove the retainer may not have a good grip. The tool is forced between the teeth. and the plate, with a high risk of slipping and damaging the teeth or even injuring the patient's mouth.

[0015] The invention thus aims to remedy in particular the aforementioned drawbacks. Summary of the invention

[0016] Thus, according to a first aspect, the invention relates to a pad, also called a retainer plate, intended to be rigidly attached to a retention element, such as a retainer wire, of a retention device. Such a retention device is preferably fixed. The pad includes, in particular, an inner face, called the intaglio surface, intended to be rigidly attached to a surface of a patient's tooth. The surface in question is typically the labial or lingual surface. The pad also includes an outer face, called the extrados, opposite the intaglio surface, and a lateral edge forming the junction between the inner and outer faces. The inner face is specifically intended to be attached to at least a portion of the relevant surface of the tooth. The pad further includes at least one notch on the inner face.The notch includes an opening on the lateral edge of the plate so as to allow a tool to be inserted into the notch when the inner face of the plate is fixed to the tooth.

[0017] The notch thus allows the tool to be inserted between the plate and the tooth to remove the plate safely and with great ease.

[0018] Depending on different aspects, it is possible to foresee one and / or the other of the characteristics below taken alone or in combination.

[0019] According to one embodiment, the inner face may include a groove intended to house at least part of the retention element, said groove opening at least at one point on the lateral edge of the plate and joining the entrance of the notch. Thus, any additional thickness of the plate caused by the notch is combined with the additional thickness expected from the groove. Since this additional thickness results in a ridge on the extrados, the notch and the groove together form a single ridge, minimizing discomfort in the patient's mouth.

[0020] According to one embodiment, the notch can be filled with a filling material less resistant than the material of the insert. Thus, when the insert is in the mouth, the risk of objects, particularly food, becoming trapped in the notch is reduced. Since the filling material is less resistant than the rest of the insert, it can be removed if necessary, for example by sandblasting.

[0021] In one embodiment, the retainer is made of metal, a metal alloy, or ceramic. The material is in all cases biocompatible. Such a retainer ensures good mechanical stability in the mouth and highly effective retention.

[0022] According to a second aspect, the invention relates to a restraint device comprising: • at least two plates, each plate comprising an internal surface for rigid fixation on one face of a tooth of the patient's dentition and an opposing external surface; • at least one added retention element rigidly fixed to each of the plates.

[0023] The retention device is intended to be placed in a patient's mouth to provide retention between at least two teeth in a so-called retention configuration, in which the inner surface of each plate is fixed to a tooth and the retention element is fixed to each plate, comprising a portion extending between the two plates, at least partially in contact with the teeth concerned by the retention. The retention device then comprises at least one plate as described above.

[0024] Preferably, all the pads of the retention device are as shown above, that is to say, they include, in particular, a notch. Any intervention on the device that requires the removal of one or more pads is thus facilitated.

[0025] According to a third aspect, the invention relates to a method for manufacturing the restraint device. The method includes, in particular: • determining the relative position between the plates and the retention element in the retention configuration of the retention device; • determining the position of at least one notch on the plate in question; • the manufacture of the plates. Brief description of the drawings

[0026] Embodiments of the invention will be described below with reference to the drawings, briefly described below:

[0027] [Fig-1] represents a top view of a lower jaw of a human patient.

[0028] [Fig.2] is a diagram representing a restraint device according to a mode of realization of the invention.

[0029] [Fig.3] is a schematic view of a restraint device comprising plates according to an embodiment of the invention.

[0030] [Fig.4] is an illustration of a tool for use with the device's pads of containment of the [Fig.3].

[0031] [Fig.5] is a three-dimensional schematic view of a model for a system aid in assembling the restraint device of the [Fig.3].

[0032] [Fig.6] is a view of the model of [Fig.5], on which a model of wafers has been added.

[0033] In the drawings, identical references designate identical or similar objects. DETAILED DESCRIPTION

[0034] 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.

[0035] Each jaw 100 supports a set of teeth comprising at least one tooth 101. Each tooth 101 comprises a face 101a called lingual, i.e. turned towards the inside of the mouth and the tongue, a face 101b called labial, i.e. turned towards the outside of the mouth and the lips or cheeks, a summit face 101c, i.e. oriented towards the other jaw, in this case the upper jaw according to the example of [Fig.1], and two lateral edges lOld. Each lateral edge of a tooth 101 can be in contact, or face, a lateral edge of an adjacent tooth, except for one lateral edge of the bottom teeth 101, at the ends of the jaw 100, i.e., the second or third molars, which is free.

[0036] Preferably, but not exclusively, the retention device 1 is intended to be fixed on the lingual face 101a of the teeth, for reasons of discretion and aesthetics.

[0037] The retention device 1 typically comprises pads 4, also called retainers, which are fixed to the teeth 101 such that each tooth 101 has at least one pad 4. Thus, if N teeth are involved in retention, the retention device 1 comprises at least N pads 4. The number N is a natural number, greater than or equal to two, and preferably greater than or equal to three. Each pad 4 has an inner face 2, called the intaglio surface, intended to face the surface 101a or 101b of the tooth 101 to which it is fixed, and an opposite outer face 3, called the extrados surface. Each pad 4 also includes a lateral edge, or contour, forming the junction between the intaglio and the extrados.

[0038] Each plate 4 is typically bonded to a tooth 101 using a fixing adhesive. The intaglio surface can be shaped to correspond at least partially to the face 101a or 101b of the tooth to which it is intended to be bonded. The intaglio surface shape can be customized from a model of the patient's teeth, or can to be standardized. The intrados 2 can be textured to increase adhesive retention for bonding to teeth. The face 101a or 101b of tooth 101, to which the plate 4 is intended to be fixed, can be finely hollowed out to accommodate the added thickness created by the plate 4 on tooth 101.

[0039] The pads 4 can be made of any type of biocompatible material. However, in order to ensure high-quality restraint with limited discomfort for the patient, the pads 4 are preferably made of metal, metal alloy, or ceramic.

[0040] The restraint device 1 comprises a restraint element 6 attached and fixed to each plate 4.

[0041] Preferably, the retention element 6 is of the wire type, meaning that it has a dimension called length that is very large compared to the other two, which may be very close or even identical. The cross-section of the retention element 6 is generally circular, square, or rectangular, but any other shape is suitable. The retention element 6 is, for example, a multi-strand metal wire, both flexible enough to be shaped by a technician, for example using a bending tool, to adapt to the teeth being treated and rigid enough to provide the required retention. The elastic properties of the retention element 6 allow it to absorb masticatory stresses and prevent the risk of fracture. As will be discussed later, the retention element 6 can also be custom-shaped and dimensioned to closely match the lingual or labial face of the teeth.

[0042] The restraint element 6 may comprise a single section extending continuously over all the plates 4 of the restraint device 1, or it may comprise several sections, each section being fixed to two successive and adjacent plates 4, i.e., plates that follow one another along the restraint element 6 without the interposition of another plate or any other element. In what follows, the restraint element 6 is considered to comprise a single continuous section and is referred to hereafter as the restraint wire 6.

[0043] The mechanical properties of the pads 4 and the retaining element 6 are generally different, because their functions are different. Thus, the pads 4 and the retaining element 6 are initially separate elements, manufactured separately, and then fixed together in an assembly step.

[0044] According to one embodiment, when the retaining plates 4 and wire 6 are metallic, the assembly can be carried out by welding or brazing, outside the patient's mouth. Welding ensures a rigid, high-quality fixation with high mechanical strength and limits discomfort in the mouth.

[0045] According to another embodiment, the assembly between the plates 4 and the wire 6 can be carried out by gluing, for example using a biocompatible acrylic resin type glue.

[0046] The intaglio surface 2 of each plate 4 is shaped to correspond to the portion of the tooth 101 surface on which the plate 4 is intended to be placed. When the wire 6 is fixed to the intaglio surface 2, the shape of the intaglio surface 2 takes into account the presence of the retention wire 6. In this case, the intaglio surface 2 includes a groove 2a in which the wire 6 is housed.

[0047] The intrados 2 includes at least one notch 7, i.e. a recess, which opens at least once on the lateral edge 5 of the plate 4, forming the entrance 7a of the notch 7. In other words, the notch 7 is concave in shape, turned towards the inside of the plate 4.

[0048] When the plate 4 is fixed to a tooth 101 by its intrados 2, the notch 7 allows for a localized, intentional, and controlled space between the plate 4 and the surface of the tooth 101 to which the plate 4 is fixed. The notch 7 is positioned and sized to allow the insertion, through the opening 7a, of a removal tool 20 between the plate 4 and the surface 101a, 101b of the tooth 101 to which the plate 4 is fixed, in order to exert force on the plate 4 and detach it from the tooth 101, while limiting the risk of injuring the patient's mouth.

[0049] The notch 7 is, for example, a few millimeters long, for example, 1 to 3 mm. The length of the notch 7 here refers to its extension on the intrados 2 of the plate from the opening 7a. The length of the notch 7 may, however, depend on the dimensions of the plate 4 in question. The notch 7 may have a substantially conical, or truncated conical, shape along its length. The maximum width of the notch 7, that is, its opening dimension 7a, on the lateral edge 5 of the plate, is, for example, greater than 0.5 mm, and for example, on the order of 1 mm. However, the dimensions of the opening 7a of the notch 7 may depend on the dimensions of the plate 4.

[0050] The inlet 7a of the notch 7 can be positioned at any level on the lateral edge 5 of the plate. Preferably, the inlet 7a of the notch is positioned substantially in the direction of the interdental line when the plate 4 is fixed to the tooth 101, that is, substantially in the direction of a tooth 101 adjacent to the one on which the plate 4 is fixed. In one embodiment, the inlet 7a of the notch is located on the lateral edge 5 substantially at the same level as a point where the groove 2a opens onto the lateral edge 5. For example, the groove 2a meets the inlet 7a of the notch 7 on the lateral edge 5. In this embodiment, the notch 7 then extends lengthwise substantially directly under the groove 2a, or even merges with the groove 2a. Thus, the number of reliefs on the extrados 3 the plate is limited: the trench 2a and the notch 7 form a single ridge on the extrados 3.

[0051] An example of a removal tool 20 is illustrated in [Fig. 4]. According to the example, the tool 20 comprises a handle 21 for being held by a practitioner, and a shaft 22 attached to the handle, which has a curved portion 23, for example at approximately 90° to the rest of the shaft 22. The shaft 22 terminates at its free end with a point 24. Such a tool 20 allows the practitioner to exert a lever arm manually, by holding the tool 20 by the handle 21, inserting the point 24 into the notch 7 between the plate 4 and the tooth 101, and using the curved portion 23 as leverage against the tooth 101 concerned, and / or against another tooth. Preferably, as the 7a inlet of the notch is turned towards the interdental line, the curved portion 23 rests on another plate 4 of the retention device, in particular plate 4 of a tooth adjacent to the one concerned by the removal of the plate.The length of the rod 22, and / or the angle of curvature of the curved portion 23 can be adapted to provide the appropriate lever arm.

[0052] The tool 20 is made of a suitable material, appropriate for use in the patient's mouth. This is, for example, stainless steel.

[0053] We will now describe an example of a method for assembling a restraint device 1 comprising a plate 4 provided with a notch 7.

[0054] It is proposed to use an assembly aid system for the restraint device 1, which includes at least one guide. The guide 11 includes: • at least two 12-guide surfaces, each 12-guide surface being shaped to be complementary at least in part to a single plate 4 of the retention device 1, • at least one guide marker 13 for the retention element 6,

[0055] [Fig. 5] illustrates a model for defining a guide 11 comprising the guide surfaces 12 and the guide marker 13, according to one embodiment. In what follows, the terms and references guide 11, guide surface 12, and guide marker 13 will be used to designate the models of these elements in [Fig. 5], the aid system being obtained directly from the model, as will be explained later.

[0056] A guide surface 12 can be complementary, for example, to a portion of the intrados 2, as in the example of [Fig. 6], and / or to a portion of the extrados 3 and / or to a portion of the lateral edge of a plate 4.

[0057] The guide surfaces 12 and the guide marker 13 are connected and are shaped and positioned relative to each other in a predetermined manner, to be complementary to the restraint device 1 in the restraint configuration. The guide 11 thus allows, by complementarity, the relative position between the plates 4 and the restraint element 6 to be fixed. The positioning of the element 6 of The retention for assembly with the plates 4 can thus be carried out precisely and reliably thanks to the guide mark 13.

[0058] More specifically, the guide 11 blocks the translation of the containment element 6 along at least one direction in at least two directions of space.

[0059] In what follows, a containment plane is defined on the guide as the mean plane of the guide marker 13, which is substantially parallel to the mean plane of the containment element 6. The containment plane can, for example, be calculated by the least squares method applied to the distance between the points of the guide marker 13 and the containment plane. Within the containment plane, a longitudinal direction is defined, corresponding to the overall extension direction of the guide marker 13, and a transverse direction, substantially perpendicular to the longitudinal direction. Finally, a vertical direction, substantially perpendicular to the containment plane, is defined. Thus, the three translational directions in space are referred to in what follows as the longitudinal direction, the transverse direction, and the vertical direction.

[0060] The translational locking of the retaining element 6 on the guide 11 is ensured along at least the transverse and vertical directions, in at least one direction in each direction. Correct positioning along the longitudinal direction can then result from the coincidence between the retaining element 6 and the guide marker 13.

[0061] Preferably, the locking of the wire 6 on the guide 11 is ensured along the three translational degrees of freedom, in at least one direction in each degree of freedom. In order to easily remove the retaining device 1 from the guide, the locking of the wire 6 on the guide 11 is ensured along the three translational degrees of freedom, in only one direction in each degree of freedom.

[0062] Each surface 12 of the positive guide 11 is formed by a recess 16, such that each recess 16 can only correspond to a single plate 4, in shape and dimensions. More specifically, each recess 16 comprises a bottom 16a and a contour 16b: the bottom 16a may be complementary, at least in part, to the intrados 2 of a single plate 4 and / or the contour 16b may be shaped to fit, at least in part, the lateral edge of the corresponding plate 4. The bottom 16a of the recesses 16 may further comprise grooves of small width relative to the wire 6, which will serve to facilitate the drainage of any excess glue between the plates 4 and the wire 6.

[0063] The guide further includes a guide reference 13 formed on the one hand by projections 17 in relation to the bottom 16a of the guide surfaces 12 according to the example shown, and on the other hand by support portions 18.

[0064] The projections 17 thus define a support against which the wire 6 can be placed to determine its position relative to the plates 4. Preferably, the wire 6 is intended to also be in contact with the teeth 101, or at least to be as close to them as possible, so that the bearing face 17a is preferably a face of the projection 17 that extends substantially perpendicularly to the vertical direction, the entire set of bearing faces 17a of the projections 17 thus being substantially parallel to the retention plane. The projections 17 thus ensure that the retention wire 6 is locked in one direction along the vertical direction. Preferably, the vertical locking is achieved in only one direction to facilitate handling. Optionally, the projections 17 may also include a second bearing face so as to lock the wire 6 in the second direction along the vertical direction.

[0065] The projections 17 rise, for example, from the bottom 16a of the grooves 16 of the guide, substantially in a median zone along the longitudinal direction. The projections 17 are arranged along the vertical direction so that their bearing surfaces 17a ensure the correct positioning of the retaining wire 6 in the retaining plane.

[0066] The projections 17 can form a single continuous projection, but preferably they are distinct from one another in a subtle manner. The number 17 of projections is then at least equal to the number of plates 4 of the retention device. Thus, for each plate 4, at least one projection 17 can be positioned longitudinally so as to come into contact with the wire 6 at at least one point where the wire 6 crosses the lateral edge 5 of the plate 4. The shape of a projection 17 corresponds substantially to the expected shape of a notch 7, in particular conical or truncated conical. Such a projection 17 then makes it possible, as will be seen later, to form the notch 7.

[0067] The bearing portions 18 correspond to the surface portion of the teeth 101 against which the retention wire 6 bears, so as to block the translation of the retention wire 6 along the transverse direction in one direction. The bearing surface portions 18 may form a continuous bearing surface, or extend discretely.

[0068] At least one projection 17 intended to guide an end portion of the restraint wire 6 forms a stop along the longitudinal direction, in one direction. Preferably, the restraint wire 6 is blocked in a single direction along the longitudinal axis to facilitate handling of the device 1 once assembled. However, it is possible to form a longitudinal stop on two projections 17 at the two extreme portions of the restraint wire 6.

[0069] When the retaining wire 6 is pressed against the faces 17a of the projections 17, the stop and the support portions 18, it is thus blocked in translation along at least one direction in all three directions. The reliable and precise positioning of the wire 6 relative to the The plates 4 themselves positioned on the guide 11 thanks to the surfaces 12 guide is thus guaranteed.

[0070] The system may include a removable locking device for one or more plates 4.

[0071] The restraint device 1 can then be manufactured in the following manner.

[0072] First, personalized information about the patient can be obtained, for example, to create a model of their teeth, as well as prescriptions concerning, for example, the width 6 of the wire and / or the thickness of the brackets 4. This information then makes it possible to determine the retention configuration for the retention device 1. More specifically, the retention configuration includes an optimal position of the wire 6 on the patient's teeth, as well as contour limits for the brackets 4 on the teeth. The position of the notches 7 on each bracket 4 is also determined to take into account the patient's dentition and optimize the use of the tool 20. From this, the position of the projections 17 is deduced, as illustrated in [Fig. 6].

[0073] The guide 11 is then designed from the retention configuration of the retention device 1, by transforming the model of the patient's teeth 101 on which the guide surfaces 12 and the projections 17 are placed, which is the model illustrated in [Fig.5].

[0074] The guide 11 can be designed digitally and then manufactured by any known technique, including 3D printing.

[0075] Alternatively, in the case of the positive guide 11, the manufacture of the guide 11 may include taking a mold of the patient's teeth and machining the guide surfaces 12 and the guide relief 13 on the mold. The machining can be carried out precisely using numerically controlled tools.

[0076] Once the guide 11 is obtained, the retaining wire 6 is manufactured, notably from the patient's personalized information.

[0077] According to a first example, the plates 4 are also manufactured in parallel with the manufacture of the wire 6. Then, the wire 6 is applied to the guide 11, resting on the bearing surfaces 17a and the bearing portions 18. If necessary, the wire 6 can be retained on the guide 11 by the retaining device. Each plate 4 is placed against the corresponding bearing surface 12, and over the wire 6 and at least one protrusion 17: the wire 6 fits into the groove 2a of each plate 4, and the protrusion 17 fits into the notch 7. The plates 4 can then be glued against the wire 6 to assemble the retaining device 1.

[0078] According to a second example, the plates 4 are manufactured to allow for a margin of error, for example in the manufacture of the wire 6. Indeed, although the shape and dimensions of the wire 6 were determined from the patient's information, the The manufacturing process for wire 6 can introduce discrepancies that are not initially accounted for during the fabrication of the plates 4. In particular, the complex folding of wire 6 can lead to differences between the calculated optimal wire position and the final manufactured result. Therefore, it is proposed to first fabricate wire 6 and position it on the positive guide 11, following the projections 17. Then, the assembly formed by the guide 11 and the retaining wire 6 in place on the guide 11 is scanned. From this scan, the plates 4 can then be designed to perfectly match the actual retaining wire 6. The plates 4 are then manufactured in a second step, incorporating the groove 2a and the notch 7, with increased precision. Patient comfort is thus improved.

[0079] The pads 4 are in turn positioned on the guide 11 along the guide surfaces 12, and the bonding between the pads 4 and the wire 6 can be carried out. The guide 11 may optionally include openings allowing at least partial access to a contact area between each pad 4 and the wire 6, so as to allow, for example, precise application of the adhesive. The size and position of such openings do not interfere with the correct positioning of the pads and the wire 6 on the guide 11.

[0080] The assembled retention device 1 can then be placed in the patient's mouth by bonding the plates 4 to the teeth 101, possibly with the aid of a placement guide. If necessary, before placing the retention device 1 in the mouth, any excess adhesive between the plates 4 and the wire 6 can be cleaned.

[0081] The notch 7 is filled with a filling material less resistant than the material of the plate 4. This is, for example, a resin, which could be the adhesive used to fix the plate 4 to a tooth 101, or the adhesive used to bond the wire 6 to the plate. The notch 7 can be filled before placing the device in the mouth, for example, when the wire 6 is bonded to the plates 4 with the assembly adhesive, or just before bonding the plates to the teeth with the adhesive. Thus, the risk of food, or any other object, becoming trapped in the notch 7 is virtually nil.

[0082] When a insert 4 needs to be removed, for example when the wire 6 needs to be changed, the notch 7 is first released. For this purpose, a sandblasting process can be used, in which a fine jet of a powdery material such as alumina is precisely projected onto the filling material in the notch 7, so as to at least partially expose the notch 7. The tool 20 can then be used as described above to remove the insert 4 with increased ease and safety.

Claims

Demands

1. A plate (4) intended to be rigidly fixed to a retention element (6) of a retention device (1), said plate (4) comprising an inner face (2) intended to be rigidly fixed to a face (101a, 101b) of a patient's tooth (101), an opposing outer face (3), and a lateral edge (5) forming the junction between the inner face (2) and the outer face (3), the inner face (2) being intended to be fixed to at least a portion of the relevant face (101a, 101b) of the tooth (101), the plate (4) further comprising at least one notch (7) on the inner face (2), the notch (7) comprising an opening (7a) leading to the lateral edge (5) of the plate so as to permit the insertion of a tool (20) into the notch (7) when the face (2) internal part of the plate (4) is fixed on the tooth (101).

2. Plate (4) according to claim 1, wherein the inner face (2) comprises a trench (2a) intended to house at least part of the retaining element (6), said trench (2a) opening at least at one place on the lateral edge (5) of the plate (4) and joining the inlet (7a) of the notch (7).

3. Plate (4) according to claim 1 or claim 2, wherein the notch (7) is filled with a filling material less resistant than the material of the plate (4).

4. Plate (4) according to any one of the preceding claims, wherein the plate (4) is made of metal, metal alloy or ceramic.

5. A retention device (1) comprising: • at least two plates (4), each plate (4) comprising an internal surface (2) for rigid fixation to one face (101a, 101b) of a tooth (101) of the patient's dentition and an opposing external surface (3); • at least one retention element (6) attached and rigidly fixed to each of the plates (4); the retention device (1) being intended to be placed in the mouth of a patient to provide retention between at least two teeth (101) in a so-called retention configuration, in which the internal surface (2) of each plate (4) is fixed to a tooth (101) and the retention element (6) fixed to each plate (4) comprises a portion (61) extending between the two plates (4) at least partly in contact with the teeth concerned by the retention, the retention device (1) comprising at least one plate (4) according to any one of the preceding claims,

6. Method of manufacturing a restraint device (1) according to the preceding claim, comprising: • determining the relative position between the pads (4) and the restraint element (6) in the restraint configuration of the restraint device (1); • determining the position of at least one notch (7) on the pad (4) concerned; • manufacturing the pads (4).

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