WO2025017269A1 - Orthodontic bracket - Google Patents

Abstract

Orthodontic bracket (10) comprising a body having a base intended to be fixed to the outer surface of a tooth and a vestibular part intended to retain an orthodontic arch (13) extending in a generally mesio-distal direction, characterized in that it comprises a receptacle (111) at least partially open on said base, in order to open onto said tooth when said base is fixed to the outer surface of said tooth, and intended to receive an adhesive material defining, once hardened, a retention pad for an orthodontic aligner, a separation rib forming a projection of the base, placed on the periphery and in the extension of said receptacle (111), configured to separate the adhesive material intended to be received in said receptacle (111) from the adhesive material intended to be received on the rest of said base, and a fold groove (114) on the vestibular part, transverse thereto, and facing said receptacle (111).

Description

Description

Title: Orthodontic bracket

Technical field

[0001] The present disclosure relates to the field of orthodontic brackets or implants. According to another aspect, the invention relates to an extraction tool for such an orthodontic bracket or implant.

Previous technique

[0002] Various devices are known for orthodontic care, for the treatment of tooth positioning. In particular, orthodontic implants, or orthodontic brackets are particularly effective in correcting occlusion problems, filling the gap between teeth, aligning teeth or correcting dental crowding. These are implants that are individually glued to the teeth and through which an orthodontic arch passes. Thanks to the pressure exerted by the brackets and the arch, the teeth see their position corrected after a long treatment period, generally several months or years.

[0003] Depending on the needs and budgets, there are several types, in particular, metal brackets are known and very widespread for their various advantages such as their resistance or their versatility. However, due to the duration of the treatment, there is an increasingly strong demand from patients for more comfortable treatments.

[0004] First of all, from the point of view of physical comfort, brackets with a smoother and more rounded shape are known, in order to limit snagging and possible oral-gingival injuries. Ceramic brackets are also known to provide aesthetic comfort by being less visible.

[0005] Sapphire crystal brackets are known which, although more expensive, allow both effective treatment with physical and aesthetic comfort due to their transparency.

[0006] In addition, for physical and aesthetic comfort purposes, some treatments include the fitting of an orthodontic alignment splint. Such a splint, custom-made for each patient's teeth, remains an effective and widespread way to correct dental alignment problems. A major advantage of orthodontic splints is their transparency.

[0007] Also, treatments then combine both brackets and orthodontic aligners. In particular, the brackets first perform a large part of the treatment first, and the end of the treatment is performed by one or more aligners, so as to free the patient from the discomfort caused by the brackets as quickly as possible while maintaining a very reasonable treatment duration.

[0008] However, fitting such a splint requires preparing supports on the teeth that protrude from the enamel of the teeth, called "retention pads", intended to hold the splint firmly on the teeth. Thus, for such treatments, before fitting the splint, the brackets must be removed, the tooth cleaned of the glue that was used to bond the brackets, and a retention pad must be molded on the surface of the tooth. Generally, such retention pads are formed from a material similar or identical to the adhesive material used to bond the brackets.

[0009] In addition, the alignment splint is generally modeled by computer and requires a faithful impression of the patient's teeth. To make a sufficiently faithful impression, the patient's brackets are removed. From this impression, a splint, called a transfer splint, is made, serving as a mold for forming retention pads on the patient's teeth, and a first treatment splint requiring the retention pads. In addition to the waste of the transfer splint which is only used to form the retention pads, the patient remains without treatment during the manufacturing time (one to two weeks) of the two splints: his brackets having been removed.

[0010] It is also noted that in other treatments, aligners are sometimes used before brackets, in which case, when switching from aligners to brackets, the patient's teeth are cleaned of retention studs, the precision value of which in their placement is lost.

[0011] There is a need to improve this situation in order to overcome the current drawbacks of the prior art cited above.

Summary

[0012] The present disclosure improves the situation.

[0013] An orthodontic bracket is provided comprising a body having a base intended to be fixed to the external surface of a tooth and a vestibular portion intended to retain an orthodontic arch extending in a generally mesio-distal direction, characterized in that it comprises:

- a housing at least partly open on said base to open onto said tooth when said base is fixed on the external surface of said tooth, and intended to receive an adhesive material defining, once hardened, a retention block for orthodontic gutter, or intended to receive an already hardened retention block,

- a separation rib projecting from the base, placed around the perimeter and in the extension of said housing, configured to separate the adhesive material intended to be received in said housing from the adhesive material intended to be received on the rest of said base, and

- a fold groove on the vestibular part, transverse to it, and opposite said housing.

[0014] In a variant, said bracket can fold around said folding groove, and alternate between:

- an initial state, in which the bracket is in a functional configuration,

- a folded state, in which the bracket is folded around said folding groove and separated from any contents of said housing to release the retention stud.

[0015] In one embodiment of the bracket, said body comprises:

- a base intended to be fixed on said tooth, comprising said housing, said separation rib and said folding groove, and further comprising a channel configured to receive an orthodontic arch, and

- a valve, articulating with said base and defining at least two positions: o an open position in which the valve does not cover said channel of the base and allows the insertion of an orthodontic arch into it, and o a closed position in which the valve at least partially covers said channel, thus retaining any orthodontic arch previously inserted into said channel.

[0016] Advantageously, said valve is removable.

[0017] In variants of the invention,

- the base comprises a guide rail, and at least one stop notch positioned along the longitudinal central axis of said guide rail, and

- the valve comprises a transverse slide configured to articulate with said guide rail, and a stop tooth projecting from the valve, such that during articulation, the stop tooth can be housed in the stop notch, thus marking a position of the valve. [0018] Advantageously, said folding groove extends in a mesio-distal direction in said channel.

[0019] Alternatively, the valve includes a support bracket projecting at one end, configured to receive an elastomeric ligature.

[0020] Advantageously, the body of the orthodontic bracket comprises gripping poles placed at the two ends of the body of the bracket, these poles thus being arranged on either side of the folding groove, these gripping poles being configured to receive a part of an extraction tool and facilitate the folding of said body.

[0021] And advantageously, the gripping poles are made in the widest and strongest parts of the bracket.

[0022] Even more advantageously, the gripping poles can also be used for the insertion of elastomeric ligatures, for certain patient treatments.

[0023] Alternatively, the walls of said housing are smooth.

[0024] Alternatively, the walls of said housing are covered with a surface coating reducing their adhesion to adhesive materials.

[0025] In variants, said housing extends in a vestibulo-lingual direction over 0.5 to 3 millimeters and in the other directions over less than 3 millimeters.

[0026] Advantageously, said base intended to be fixed to the external surface of a tooth comprises a plurality of support feet, projecting from the base and distributed thereon, preferably equally or equidistantly. Advantageously, they are placed around the periphery of the surface of the base.

[0027] These feet may have different lengths to give a particular torque to the present bracket and/or to adapt to the vestibular anatomy of the tooth.

[0028] Alternatively, this bracket may comprise a hollow insert intended to be attached to its housing, this insert comprising, at one end, two lateral wings intended to at least partially cover said separation rib, and able to extend over a part of said base, said lateral wings being configured to impart a predetermined torque to said bracket relative to said external surface of the tooth, said lateral wings being able to be curved to adapt to the vestibular anatomy of the corresponding tooth.

[0029] Such an accessory, or insert, advantageously makes it possible to have a common flat base of the brackets and by the addition of such an insert, or accessory, received in part in the housing, allow to confer a torque angle, for example of +/- 5° to a given bracket.

[0030] Such a hollow insert can be fixed in the housing by fitting it into the latter or by clipping it into the latter.

[0031] Of course, this hollow insert can have a frame at its end, instead of side wings, which completely covers the separation rib.

[0032] It is noted that when said lateral wings are adapted to the vestibular anatomy of the corresponding tooth, they ensure comfort of installation for the operator and stability of the bracket.

[0033] Alternatively, it is possible to give a particular shape by molding to the base and possibly to the separation rib so that they match the anatomy of the supporting tooth.

[0034] Advantageously, the bracket can be produced mainly:

- in a metallic material, such as stainless steel, titanium or a nickel-based alloy, or in a ceramic, such as a zirconia-alumina alloy, or in a composite material, such as polyetheretherketone, or

- in sapphire crystal.

[0035] According to a second aspect of the invention, there is provided a device for gripping the gripping poles of an orthodontic bracket, the gripping device being provided with two gripping arms, configured to be inserted respectively into each of the gripping poles of said orthodontic bracket, to allow it to be folded around the folding groove.

[0036] According to a third aspect of the invention, there is provided an assembly for forming a retention pad for an orthodontic splint comprising an orthodontic bracket, and a prosthetic sealing substance such as a liquid or viscous adhesive substance or a composite, preferably self-polymerizable or photopolymerizable, or a cement, said prosthetic sealing substance being intended to be received at least in said housing to form by hardening a retention pad for an orthodontic splint. [0037] According to a fourth aspect of the invention, there is provided a method for forming a retention pad on a destination surface from an orthodontic bracket, characterized in that the following steps are carried out:

- providing an orthodontic bracket comprising a body having a base intended to be fixed on said destination surface and an external part intended to retain an arch, and further comprising: o an open housing on said base and opening onto said destination surface, and configured to receive an adhesive material defining, once hardened, a retention pad, o a separation rib projecting from the base and on the periphery and in the extension of said housing, configured to remain free of adhesive material, thus separating the adhesive material of said housing from the adhesive material of said base, and o a folding groove on the external part, transverse to the latter, and facing said housing so that said bracket can fold around said folding groove, and alternate between:

- an initial state, in which the bracket is in a functional configuration,

- a folded state, in which the bracket is folded around said folding groove and separated from the contents of said housing, and in which the following is carried out:

- an application of an adhesive material on the base of said bracket, comprising the filling of said housing with adhesive material,

- an affixing of the base of said bracket on the destination surface, during which said separation rib comes into direct contact with the destination surface,

- a hardening of the adhesive material, fixing said bracket to the destination surface and forming a retention pad in said retention bracket housing,

- folding said bracket around said folding groove, thereby releasing the contents of said housing,

- an extraction of said bracket from the destination surface, so that the pad formed of adhesive material remains securely fixed to the destination surface.

Brief description of the drawings

[0038] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analysis of the attached drawings, in which:

Fig. 1

[0039] [Fig. f] schematically shows a bracket and its main components according to one embodiment. Fig. 2

[0040] [Fig. 2] schematically shows the base of a bracket according to one embodiment.

Fig. 3

[0041] [Fig. 3] schematically shows the flap of a bracket according to one embodiment.

Fig. 4

[0042] [Fig. 4] shows a bracket with a flap in the open position configured to receive an elastomeric ligature according to one embodiment.

Fig. 5

[0043] [Fig. 5] shows a mesial sectional view of a bracket according to one embodiment.

Fig. 6

[0044] [Fig. 6] shows the base of Figure 2 from another point of view.

Fig. 7

[0045] [Fig. 7] shows a variant of the base illustrated in Figure 6.

Fig. 8

[0046] [Fig. 8] schematically shows in a mesial view a bracket bending under the force of an extraction tool according to one embodiment.

Fig. 9

[0047] [Fig. 9] schematically shows the reference axes in a mouth comprising a bracket according to one embodiment.

Fig. 10

[0048] [Fig. 10] is a schematic perspective representation of a bracket according to another embodiment of the invention.

Fig. 11

[0049] [Fig. 11] shows the base of the bracket illustrated in Fig. 10.

Fig. 12

[0050] [Fig. 12] is a longitudinal sectional view of the bracket illustrated in Fig. 10.

Fig. 13

[0051] [Fig. 13] is a bottom and perspective view of the single flap of the bracket illustrated in Fig. 10.

Fig. 14

[0052] [Fig. 14] is a view of the bracket illustrated in Fig. 10, in which the flap is in the withdrawn position. Description of the embodiments

[0053] Reference is now made to Figure 1 which schematically shows a bracket and its main components according to one embodiment, and to Figure 9 which schematically shows the reference axes in a mouth in which a bracket is located. It is noted that the measurements are not necessarily to scale.

[0054] According to the present invention, the bracket 10 comprises a body intended on a first internal side 332, that is to say in the direction of the tooth, (also called "lingual" 332, in the direction of the tongue) to be fixed to a tooth and on a second external or vestibular side 331 (that is to say in the direction of the cheek or the lips) to retain an orthodontic arch 13. This arch 13 generally extends in a mesial direction 311, that is to say towards the median line 310 of the dental arch, and in a distal direction 312 to the median line 310. The so-called mesio-distal direction of the arch 13 thus follows the dental arch.

[0055] We also define a gingival direction 321, that is to say oriented towards the gum, and occlusal 322 opposite to the gingival direction 321, towards the tip of the tooth or the closing of the jaw.

[0056] The body of the bracket 10 comprises two parts:

- a base 11 is the part intended to be glued to a tooth and serve as a support for

- a flap 12 which articulates with the base 11 to be able to effectively retain the orthodontic arch 13.

[0057] Reference is now made to Figures 2 and 3 showing respectively schematically the base and the flap of a bracket according to one embodiment of the invention.

[0058] The base 11 comprises a guide rail 115, while the valve 12 comprises a slide 125. The guide rail 115 and the slide 125 are sized to be able to cooperate together and advantageously allow the valve 12 to perform a translational movement on the base 11.

[0059] Advantageously, the guide rail 115 can have a narrower width at its base (on a lingual side 332) than at its upper face (vestibular 331), so as to prevent a vestibulo-lingual movement of the flap 12 on the base 11, and to maintain the rail 115 in the slide 125 by forming a tenon-mortise system.

[0060] Advantageously, the guide rail 115 extends in an occluso-gingival direction (i.e. from the tip of the tooth towards the gum), orthogonally to the insertion channel 110 intended to receive an orthodontic arch 13 in a mesio-distal direction. This therefore allows the flap 12 to cooperate with the base 11 to completely surround and effectively retain the arch 13.

[0061] In a variant not illustrated, the valve is a cap which is fixed (for example clipped) onto the base by directly surrounding an arc 13 previously inserted into the insertion channel 110.

[0062] Advantageously, the base 11 of the invention comprises stop notches 116, and the valve 12 comprises a stop tooth 126, such that when the valve 12 performs a translational movement on the rail 115 of the base 11, the stop tooth 126 can be housed in the different stop notches 116 and thus marks positions at each stop notch.

[0063] In particular, a first stop notch 116 makes it possible to maintain the valve 12 in a position which closes the insertion channel (and surrounds a possible arc 13), this position is called “closed position” or “front position”. Figure 1 illustrates for example a valve 12 in the closed position.

[0064] Alternatively, another stop notch 116 holds the valve 12 sufficiently far from the insertion channel 110 to allow the insertion of an arc 13 into the latter. The valve 12 is then said to be in the “open position” or “rear position”. FIG. 4 illustrates for example a valve 12 in the open position.

[0065] Furthermore, the valve 12 may comprise a second tooth 122, called an open stop, in order to advantageously limit, by a stop on the base 11, a translation of the valve which would take it further than an open position.

[0066] Alternatively, the valve 12 is advantageously removable and can be interchanged. For example, as illustrated in FIG. 4, the valve 12 has been interchanged for a version of the valve 12 which includes a bracket 120, intended to receive an orthodontic elastic.

[0067] In addition, the base 11 comprises a concave stop 117, into which the valve 12 is inserted in the closed position. By its design, this stop 117 advantageously makes it possible to recenter the valve 12 on the guide rail 115.

[0068] Advantageously, in the closed position, the flap 12 forms with the base 11 a substantially continuous and smooth vestibular surface, in order to avoid potential injuries arising from the bracket catching on the patient's cheek or lip and to provide the latter with significant comfort.

[0069] The valve 12 can also advantageously comprise a gripping zone 121, configured to receive a tool for manipulating the valve 12 on the rail 115 of the base 10, in particular to alternate it between a open and closed position, and/or to be able to remove it completely from the guide rail 115.

[0070] In a variant not illustrated, the body of the bracket 10 is made up of a single base comprising a mechanism for retaining the arch 13, such as a ratchet or a retention tooth. Such a variant advantageously makes it possible to limit the number of parts of the bracket while maintaining sufficient effectiveness thereof for treatment.

[0071] Reference is now made to Figure 5 which shows a mesial section view of the bracket 10 according to one embodiment, to Figure 6 which presents the base 11 from a predominantly lingual point of view and to Figure 7 which presents a variant of this base 11.

[0072] The bracket 10 advantageously comprises a housing 111 designed to receive an adhesive material and form a retention pad. This retention pad is in this way already formed at the time of placing the bracket on the patient's tooth. Once the bracket is removed, the retention pad remains on the tooth to advantageously ensure the treatment by gutter which follows, without requiring any additional operation on the part of the practitioner.

[0073] This housing 111 is advantageously open on the base 113 intended to be glued to a tooth of the patient. When adhesive material is applied to the base 113, the housing is advantageously filled with adhesive material at the same time.

[0074] In different embodiments, the housing 111 can be filled with a material different from the glue applied to the base 113, in particular a material specific to the retention pads.

[0075] In order to cleanly separate the material on the base 113 from the material contained in the housing 111, the bracket 10 comprises a separation rib 112 in relief on the base 113 and on the periphery of the housing 111, the rib 112 then extending the housing 111. When the bracket 10 is placed on a patient's tooth, the separation rib 112 is placed in direct contact with the tooth and then remains free of glue.

[0076] Advantageously, by construction, the relief created by this separation rib pushes the adhesive material on its sides when the practitioner sticks the bracket 10 on the tooth. Thus the groove can have an oblique profile on one or more sides so that the material thus pushed escapes more easily.

[0077] Alternatively, the separation rib can be easily scraped, prior to placing the bracket 10 on a tooth, to remain free of material. adhesive, without further adhesive material being removed from the base 113 or the housing 111.

[0078] Advantageously, the base 113 may have a surface relief in order to increase the contact interface with the adhesive material; preferably, the base 113 is striated.

[0079] Similarly, the base 113 may have cavities or holes (not shown) so as to increase the volume of adhesive material and/or the contact surface with the adhesive material. These holes, and their edges with the base 113, are then intended to receive at least part of the adhesive material to allow better adhesion of the base 113, and for example, the internal surfaces of the holes may also have a surface relief.

[0080] Alternatively, as illustrated in FIG. 7, the base 113 may comprise a set of support feet 1131 to advantageously limit the risks of the bracket 10 tilting or of inaccuracy when installing it.

[0081] In addition, they advantageously limit the shearing and rotational forces around a vestibulo-lingual axis of the base 11 on the tooth. These support feet 1131 are advantageously distributed on the base 113 and even more advantageously on the intrados of the periphery of the base 113 to project therewith.

[0082] The support feet 1131 advantageously protrude as much as the separation rib 112, with the base 113, so that both the rib and the feet come into contact with the tooth when the bracket 10 is placed, and are thus at least partially free of adhesive material. The support feet are between 0.2 millimeters and 1 millimeter thick, and preferably 0.5 millimeters, and ideally, as much as the separation rib.

[0083] The support feet 1131 can adopt different shapes, for example and in a non-exhaustive manner, they can be in the shape of a cylinder, a half-sphere as illustrated, a parallelepiped or more generally a prismatoid.

[0084] Advantageously, the support feet are distributed equally or almost equally, on the base 113 or on the periphery thereof, for example 4 in number, in a diamond shape at the gingival, occlusal, mesial and distal ends, or as illustrated in FIG. 7, 6 in number in the shape of a hexagon (regular or almost regular).

[0085] The housing 111 advantageously comprises a smooth surface preventing the adhesive material contained therein from adhering to the bracket 10. Indeed, during extraction of the bracket 10, the adhesive material contained in the housing 111 then does not remain attached to the bracket 10, so that the retention pad thus formed is whole and securely attached to the tooth.

[0086] The housing 111 may also include fillets 1111 or chamfers, on its internal edges, so as to more easily release the retention stud when extracting the bracket.

[0087] Alternatively, in a non-illustrated variant, the housing 111 may comprise one or more holes opening out, preferably in a vestibular direction, so as to limit any suction effect when extracting the bracket.

[0088] Advantageously, the housing 111 may comprise a surface coating reducing its adhesion to the material it contains. For example, a sterile water-based lubricating gel present on the internal walls of the housing 111 makes it possible to ensure extraction of the bracket 10 from the tooth without snagging the material of the housing 111.

[0089] The housing 111 thus serves as a mold for the retention block, and can take different shapes. For example, it can take a parallelepiped shape as illustrated, or a cylindrical, pyramidal, conical, prismatic shape, etc. The shape of the housing can be advantageously adapted to different types of orthodontic gutters.

[0090] Advantageously, in a variant not shown, the housing may have a shape that can be adapted by inserting an adapter. For example, in a cylindrical housing, an adapter whose outer surface is exactly the same cylindrical shape is inserted and fixed there by fixing means provided for this purpose in the housing. The adapter itself then comprises a second housing of smaller size and of a different shape, for example cubic. This makes it possible, in this example, to adapt a cylindrical housing into a smaller cubic housing.

[0091] Generally, a housing 111 extends over a depth (vestibulo-lingual) of 0.5 to 3 millimeters and preferably 1 millimeter, and its shape is inscribed in a circle with a diameter of less than 5 millimeters (in a plane normal to the depth).

[0092] Preferably, the housing 111 and the rib are configured to form a retention pad whose shape and dimensions make it possible to support an orthodontic splint. [0093] The precise location and exact shape of the housing 111 in the bracket 10 provide a great advantage in the treatment of the patient, since it is then possible to make a dental impression with the brackets, and to deduce exactly the location of the retention studs on the teeth when these are released, from the location of the brackets.

[0094] In order to be able to release the retention stud more easily, the bracket 10, and more particularly the base 11, comprises a folding groove 114. Advantageously, this folding groove 114 is placed on the vestibular side of the bracket, and its depth extends in a lingual direction 332. Furthermore, the folding groove 114 is advantageously transverse to the bracket 10.

[0095] Advantageously, such a groove 114 makes it possible to provide fragility to the bracket 10 and allows it to be able to bend. Indeed, the groove being transverse, if two forces, called bending forces, are applied respectively on each side of the groove (in a single first vestibular direction), the induced moments of force (of opposite signs) tend to bend the bracket 10 at the bending groove 114. The bracket 10 can then pass from an initial state in which it is in a functional configuration to a folded state.

[0096] The bracket 10 can thus bend around the folding groove 114, by the shape of the groove and by the elasticity intrinsic to the material of the bracket. In a variant, the groove is in a material different from the bracket, advantageously improving the elasticity and reducing the risk of breakage.

[0097] Advantageously, the bracket can thus undergo elastic deformation in the folding groove 114, in which case the bracket returns to its initial position when the folding forces cease. Or, alternatively, the bracket 10 can undergo plastic deformation and maintain a folded position when the folding forces cease.

[0098] In these variants, the bracket can thus be made mainly of a metallic material, such as stainless steel, titanium or a nickel-based alloy, or of ceramic such as a zirconia-alumina alloy, or of a composite material such as polyetheretherketone (PEEK), or of sapphire crystal and advantageously retain its foldable nature.

[0099] Alternatively, it is advantageously possible to adapt the depth and/or the profile of the folding groove during the manufacture of the bracket, in particular depending on the material used for the orthodontic bracket at the level of the folding groove. [0100] In a non-illustrated variant, the groove may comprise a hinge articulating the walls of the groove together, in order to advantageously facilitate folding around this hinge and limit the risk of breakage.

[0101] Alternatively, in another embodiment, the bracket may be frangible at the groove of the groove 114, so as to be able to release the retention stud when it is broken.

[0102] The groove 114 is thus advantageously placed opposite the housing 111. When the bracket 10 is folded, the housing 111 gains volume, and then easily releases the retention pad made of adhesive material that it contained and molded.

[0103] Although the groove 114 may extend transversely in a generally occluso-gingival direction, it is advantageous for the groove 114 to extend transversely in a mesio-distal direction, and even more advantageously from the insertion channel 110 intended to receive an orthodontic arch 13.

[0104] The groove thus placed at the bottom of the channel 110 is located on an area of the bracket where the vestibulo-lingual thickness is advantageously low, and where the channel

110 (empty of any orthodontic arch 13) leaves space for the vestibular parts of the bracket 10 to move during bending.

[0105] Advantageously, the gingival and occlusal walls of the canal 110 can meet during folding, thus creating a stop to avoid breaking the bracket in the folding groove 114. The bracket can thus advantageously fold without breaking.

[0106] Alternatively, the folding groove 114 has a V-shaped section, the walls of which form a stop during folding.

[0107] In another embodiment, for a treatment in which the bracket is to be placed after a treatment by splint, retention pads are already present on the surface of the patient's teeth. The bracket 10, the housing of which

111 is empty (only the base 113 then has an adhesive material), can be advantageously folded, and placed so that the retention stud already present is correctly positioned in the housing 111, and unfolded in order to maintain the retention stud in the housing 111. The bracket placed in this way on the tooth of a patient advantageously uses the precision of the positioning of the retention stud (positioned using a faithful impression of the patient's teeth).

[0108] Reference is now made to Figure 8, which illustrates in a mesial view a bracket, according to one embodiment, being bent by an extraction tool. [0109] The bracket advantageously comprises gripping poles 118, located at its occlusal and gingival ends. These gripping poles 118 thus easily allow the insertion of an extraction tool to exert said forces. Their extreme distance from the groove 114 advantageously allow an optimal lever arm to bend the bracket 10.

[0110] In addition, the gripping poles 118 advantageously comprise chamfers or fillets on their outer periphery, facilitating the entry into said poles 118 of the jaw of an extraction tool.

[0111] Advantageously, a third force (opposite to the first two, in a lingual direction 332) can be applied at the groove, so as to facilitate folding by concentrating the forces in the folding groove.

[0112] The bracket may thus comprise a support zone partly on the groove 114, advantageously making it possible to receive and maintain a support arm of an extraction tool. The support zone may thus be a slight depression (of a depth less than that of the groove) in which such a support arm can be inserted.

[0113] Alternatively, the support zone may have a projecting element and the support arm may have the imprint of this element, so as to form a recess and advantageously prevent the tool from slipping.

[0114] A bracket 10 in such a folded state can be unfolded and returned to an initial state with a functional configuration, by its intrinsic elasticity or by applying opposing forces if it has undergone plastic deformation. This characteristic gives the bracket a removable character, since it can be folded and removed by releasing the retention studs for the time to carry out a treatment such as a dental impression, then unfolded and replaced around the retention stud and continue to treat the patient for the time, for example, that a splint resulting from the impression is manufactured.

[0115] Alternatively, it is advantageously possible to make a digital impression of the patient's teeth, without even requiring the extraction of the bracket, since the exact location of the retention stud of a bracket can be determined by geometry: knowing the exact shape of a bracket, it is possible to deduce the shape and location of the retention stud of a bracket from the impression.

[0116] Alternatively, the bracket 10 includes extraction handles 119 at the mesial and distal ends, which allow the bracket to be gripped and a shearing or “peeling” force to be applied to the bracket 10 on the tooth. Advantageously, this effort allows the bracket to be removed by tearing the retention stud from the fff housing, in cases where it would not prove useful during a particular treatment or for a particular tooth.

[0117] Alternatively, the guide rail 115 of the base 11 can have the role of the extraction handles 119. Indeed, for example when the guide rail 115 extending in an occluso-gingival direction has a narrower width at its base (on a lingual side 332) than at its upper face (vestibular direction 331), the cavity thus created can allow the bracket 10 to be gripped by an extraction tool and form a shearing force.

[0118] The extraction tool 20 thus comprises two levers, an upper lever 21 (or gingival) and a lower lever 22 (or occlusal), which are articulated around a pivot element to form a clamp.

[0119] Each lever 21, 22 thus comprises on a first side of the pivot a gripping part for the practitioner's hand, and on the other side a gripping part comprising an offset arm with a jaw 211, 221 at its end. The jaw projects and thus forms an angle with the offset arm.

[0120] Thus, the extraction tool 20 is configured so that the jaws 211, 221 are inserted into the gripping poles 118 of a bracket of the invention by a clamping movement.

[0121] Advantageously, the jaws 211, 221 are inserted there obliquely, so as to press on the internal vestibular surface of the gripping poles 118. Thus, such a clamp movement applies a force in a vestibular direction to each of the gripping poles 118.

[0122] Furthermore, the extraction tool 20 advantageously comprises a support arm 23, configured to maintain a substantially constant ratio between the two angles formed by the support arm with each of the two offset arms of the levers 21, 22, regardless of the pivot angle of the levers. Preferably, said two angles are equal, and the support arm then extends along the bisector of the opening angle formed by the levers.

[0123] For example, the ratio may be maintained substantially constant by holding the support arm loose in the pivot member, with two springs held between the support arm and each of the offset arms. Or alternatively, the support arm is retained in the pivot member by a gear system configured to maintain said angle ratio constant.

[0124] Optionally, the support arm 23 comprises at its end a hollow or projecting element so as to form an embedding of the support arm 23 in a support area of the bracket, on an element respectively projecting or hollow in this support area; it advantageously prevents the extraction tool from slipping.

[0125] In another embodiment, the extraction tool comprises a handle provided at one end with a U-shaped gripping head and preferably perpendicular to the handle, each side of which forms a gripping arm of the bracket, intended to be inserted into a gripping pole 118 of a bracket of the invention.

[0126] It is thus possible to insert the head of such a tool into the gripping poles 118 of the bracket by a movement along the mesio-distal axis. Once the head is inserted, a movement of the tool in a vestibular direction allows the bracket to be bent.

[0127] The shape of the head of such a tool is not limiting, it only determines the movement to insert itself into the gripping poles. For example, the head can follow the edges of a pyramid with a regular square base (when only 2 opposite edges starting from the apex and 2 opposite edges from the base are kept), the head then being inserted by a rotational movement around the height (central axis) of such a pyramid when it is colinear with the vestibulo-lingual axis, and translation in a lingual direction.

[0128] Figures 10 to 14 show an orthodontic bracket 40 according to another embodiment.

[0129] The elements shown in Figs. 10 to 14 and bearing the same references as those illustrated in Figs. 1 to 9 represent the same objects, which will not be described again below.

[0130] The orthodontic bracket 40, illustrated in Figs. 10 to 14, differs essentially from that disclosed in Figs. 1 to 9 in that the flap 41 is removable, and can be inserted into position on, or extracted from, the base 42 by a movement along the z axis, or else a vertical axis relative to the base 113, the latter being flat and received on a horizontal plane.

[0131] The valve 41 comprises at one end a recentering member 43 intended to cooperate and to be housed in an end-of-travel stop 44 placed on the base 42. This configuration makes it possible to eliminate the grooves and therefore the movement of the valve 41 is done by sliding.

[0132] The removal of the valve 41 is carried out by sliding and vertical withdrawal using a tool inserted into a slot 45 provided for this purpose in the body of the valve 41. [0133] Very advantageously, this flap 41 being removable, it can be changed during orthodontic treatment:

- to add an intermaxillary elastic support bracket,

- to change or individualize the shade corresponding to the patient's enamel shade, or

- to replace a valve worn by repeated friction movements or broken by an impact.

Claims

Claims [Claim 1] Orthodontic bracket (10) comprising a body having a base (113) intended to be fixed to the external surface of a tooth and a vestibular portion intended to retain an orthodontic arch (13) extending in a generally mesio-distal direction, characterized in that it comprises: - a housing (111) at least partly open on said base (113) to open onto said tooth when said base (113) is fixed on the external surface of said tooth, and intended to receive an adhesive material defining, once hardened, a retention pad for an orthodontic splint, or intended to receive a retention pad already hardened, - a separation rib (112) projecting from the base (113), placed on the periphery and in the extension of said housing (111), configured to separate the adhesive material intended to be received in said housing from the adhesive material intended to be received on the rest of said base (113), and - a folding groove (114) on the vestibular part, transverse to it, and opposite said housing. [Claim 2] Orthodontic bracket (10) according to claim 1, characterized in that said bracket can bend around said folding groove (114), and alternate between: - an initial state, in which the bracket (10) is in a functional configuration, - a folded state, in which the bracket is folded around said folding groove (114) and separated from any contents of said housing to release the retention pad. [Claim 3] Orthodontic bracket (10) according to claim 1 or 2, characterized in that said body comprises: - a base (11) intended to be fixed on said tooth, comprising said housing (111), said separation rib (112) and said folding groove (114), and further comprising a channel (110) configured to receive an orthodontic arch (13), and - a valve (12), articulated with said base and defining at least two positions: o an open position in which the valve (12) does not cover said channel (110) of the base (11) and allows the insertion of an orthodontic arch (13) therein, and o a closed position in which the valve (12) at least partly covers said channel (110), thus retaining a possible orthodontic arch (13) previously inserted in said channel (110). [Claim 4] Orthodontic bracket (10) according to the preceding claim, wherein said flap (12) is removable. [Claim 5] An orthodontic bracket (10) according to claim 3 or 4 wherein, - the base (11) comprises a guide rail (115), and at least one stop notch (116) positioned along the longitudinal central axis of said guide rail (115), and - the valve (12) comprises a transverse slide (125) configured to articulate with said guide rail (115), and a stop tooth (126) projecting from the valve (12), such that during articulation, the stop tooth (126) can be housed in the stop notch (116), thus marking a position of the valve (12). [Claim 6] An orthodontic bracket (10) according to any one of claims 3 to 5 wherein said folding groove (114) extends in a mesio-distal direction in said channel (110). [Claim 7] An orthodontic bracket (10) according to any one of claims 3 to 6 wherein the flap (12) comprises a support bracket (120) projecting at one end, configured to receive an elastomeric ligature. [Claim 8] Orthodontic bracket (10) according to any one of the preceding claims in which the body of the orthodontic bracket comprises gripping poles (118) placed at both ends of the body of the bracket, these poles (118) being thus arranged on either side of the folding groove (114), these gripping poles (118) being configured to receive a portion of an extraction tool and facilitate the folding of said body. [Claim 9] An orthodontic bracket (10) according to any preceding claim wherein the walls of said housing (111) are smooth. [Claim 10] An orthodontic bracket (10) according to any preceding claim wherein the walls of said housing (111) are covered with a surface coating configured to reduce their adhesion to adhesive materials. [Claim 11] An orthodontic bracket (10) according to any preceding claim wherein said housing (111) extends in a vestibulo-lingual direction by 0.5 to 3 millimeters and in other directions by less than 3 millimeters. [Claim 12] An orthodontic bracket (10) according to any one of claims 1 to 11, wherein said base (113) for attachment to the external surface of a tooth comprises a plurality of support feet (1131), projecting from the base and distributed thereon, preferably equally or equidistantly around the periphery of the surface of the base (113). [Claim 13] Orthodontic bracket (10) according to any one of claims 1 to 11, wherein it comprises a hollow insert attached to said housing (111), said hollow insert comprising two lateral wings intended to at least partially cover said separation rib (112), and able to extend over a portion of said base (113), said lateral wings being configured to impart a predetermined torque to said bracket relative to said external surface of the tooth, said lateral wings being able to be curved to adapt to the vestibular anatomy of the corresponding tooth. [Claim 14] Assembly for forming a retention block of an orthodontic splint comprising an orthodontic bracket (10) according to any one of claims 1 to 13, and a prosthetic sealing substance such as a liquid or viscous adhesive substance or a composite, preferably self-polymerizable or photopolymerizable, or even a cement, said prosthetic sealing substance being intended to be received at least in said housing to form by hardening a retention block for an orthodontic gutter. [Claim 15] Device for gripping the gripping poles of an orthodontic bracket (10) according to any one of claims f to 13, characterized in that the gripping device is provided with two gripping arms, configured to be inserted respectively into each of the gripping poles of said orthodontic bracket, to allow its folding around the folding groove.