Bracket with a ligation-free bracket slot for orthodontic treatment with firmly seated treatment technology

Abstract

The invention relates to a bracket (10) with a bracket slot for orthodontic treatment with firmly seated treatment technology, which bracket slot no longer requires ligation, i.e. fastening of the guide bow. As a result, the brackets used can be made much smaller and rounder, which is far more comfortable for the person being treated. The bracket (10) comprises a body (11) which has: an adhesive surface (12) for adhesively fastening to a tooth; an outer surface (14) adjacent to the adhesive surface (12); and a groove-like recess or bracket slot (20) provided in the outer surface (14) and extending parallel to a reference plane which corresponds to the occlusion plane or the gingival plane or is inclined thereto at up to ± 45°, wherein the groove-like recess (20) is limited by: a groove base (22) facing the adhesive surface (12) and comprising a groove base portion (26), two groove walls (32, 42) and a third groove wall (52). The bracket (10) is characterised in that between a first groove wall (32) and the third groove wall (52) an opening remains for introducing and removing an elastically twistable, resilient guide bow (70) after corresponding twisting of the guide bow (70), wherein the guide bow (70) has a rectangular, square or parallelogram-shaped cross section, and wherein both the first groove wall portion (36) and the second groove wall portion (46) as well as the third groove wall (52) and the groove base portion (26) serve as surfaces which, after the guide bow (70) has untwisted, cause the automatic locking of the guide bow in the recess (20). By way of recesses on the groove walls (32, 42) opposite the opening, slot-filling guide bows dimensioned exactly to the slot size can be inserted. As each tooth can be activated with a torque in the bracket longitudinal cross section in two opposite directions, there are differently designed recesses for each rotational direction or a different insertion direction.

Description

[0001] BRACKET WITH A LIGATION-FREE BRACKET SLOT FOR ORTHODONTIC TREATMENT USING FIXED TREATMENT TECHNIQUE

[0002] The present invention relates to brackets with a ligation-free bracket slot for orthodontic treatment with fixed treatment techniques.

[0003] In fixed orthodontic treatment, brackets are used with predominantly rectangular, groove-shaped recesses, called bracket slots. The guide wire is inserted into these slots from bracket to bracket, thereby transferring the corresponding forces and torques to the teeth to be moved.

[0004] Traditionally, the guide arches were ligated into the slots with wire or rubber ligatures using protruding bracket wings with undercuts. Later, self-ligating mechanisms were also developed to shorten the time-consuming process of ligating the guide arch. However, in these cases, the self-ligating mechanism only assists in ligating the arches and thus remains a treatment task.

[0005] Both the space-consuming bracket wings and the usually sharp-edged, self-ligating mechanisms usually lead to a massive enlargement of the bracket body and thus to friction and pressure problems for the patient.

[0006] The object of the present invention is to completely avoid the time-consuming ligation, to massively reduce the bracket dimensions and to create a relatively smooth surface without bulges that are annoying for the patient.

[0007] This object is achieved with a completely redesigned bracket according to claim 1. Advantageous further developments of the invention are the subject of the dependent claims.

[0008] The bracket according to the invention for orthodontic treatment with a fixed treatment technique comprises a body having: an adhesive surface for adhesive attachment to a tooth; an outer surface adjoining the adhesive surface; and a groove-shaped recess provided in the outer surface, which runs parallel to a reference plane corresponding to the occlusal plane or the gingival plane or is inclined by up to ± 45° thereto, wherein the groove-shaped recess is delimited by: a groove base facing the adhesive surface and comprising a groove base section, with a first end facing the reference plane and a second end facing away from the first end; a first groove wall having a first end facing the adhesive surface and a second end facing away from the first end, which adjoins the first end of the groove base at its first end and has a first groove wall section running parallel to the reference plane;a second groove wall with a first end facing the adhesive surface and a second end facing away from the first end, which adjoins the second end of the groove base at its first end and has a second groove wall section running approximately parallel to the first groove wall section, wherein the second groove wall extends further away from the adhesive surface than the first groove wall, and a third groove wall with a first end facing the reference plane and a second end facing away from the first end, which adjoins the second end of the second groove wall in one piece and in a dimensionally stable manner at its second end and extends less far towards the reference plane than the groove base.

[0009] Between the second end of the first groove wall and the second end of the third groove wall there remains an opening for inserting and removing an elastically twistable, spring-elastic guide arch after corresponding twisting of the guide arch, wherein the guide arch has a rectangular, square or parallelogram-shaped cross-section, and wherein both the first groove wall section and the second groove wall section as well as the third groove wall and the groove base section serve as surfaces which, after the twisting of the guide arch has been reset, cause it to lock automatically in the recess, i.e. that the guide arch is ligation-free. The guide arch does not necessarily lie against all four of the aforementioned surfaces at the same time, but the contact of the guide arch against just two of them can be sufficient for locking. The elastically twistable, spring-elastic guide arch can have rounded corners.

[0010] If the groove-shaped recess is to be aligned essentially perpendicular to the bonding surface, the reference plane corresponds to the occlusal plane or the gingival plane, depending on whether the guide bow is to be inserted from the occlusal plane or the gingival plane, depending on the desired direction of tooth rotation. Depending on the desired treatment, it may be advantageous if the reference plane, and thus also the orientation of the groove-shaped recess, is inclined by up to ± 45° relative to the occlusal plane or the gingival plane.

[0011] Thus, the guide arch is not inserted into the groove-shaped recess or bracket slot in a straight line throughout, but rather by first twisting the guide arch at the point on the bracket against the direction in which torque is later to be exerted - this is often also referred to as "torqued" - and in this twisted position is inserted into the groove through the opening at an open corner in an oblique-lateral direction. As soon as the guide arch is received far enough in the groove, it is released and, due to its elasticity, can release itself from its twisted position. The guide arch thus automatically clicks into the groove and is thus secured. It can then exert the intended torque on the corresponding surfaces of the groove and thus on the bracket and ultimately the tooth. Due to the inventive design of the bracket, which does not require any auxiliary elements for ligating orSecuring the guide bow in the groove-shaped recess not only allows the bracket to be designed to be small and have a smooth surface, but also completely avoids the otherwise time-consuming ligation, as securing is done automatically by releasing the twisted guide bow.

[0012] A particularly simple adaptation to the needs of orthodontic treatment is achieved by providing the bracket, depending on the intended torque direction, either with a recess in the groove base area and a recess in the wall area, or with a recess in the groove base area and a recess in the wall area, depending on the intended torque direction. The term "in the area" here means a section a short distance from the element in question or directly adjacent to it. Before bonding the bracket, the torque direction of the bracket must be determined, thereby establishing a corresponding torque effect. This, however, is usually not a problem.

[0013] It is advantageous if fillets are provided in the groove base side recess and in the wall side recess, which can facilitate the complete insertion of the guide arch and the resetting of the twisting of the guide arch, since this greatly reduces the risk of the guide arch becoming caught and facilitates the locking of the twisted guide arch (i.e. pre-activated by the twisting).

[0014] The insertion of the twisted guide sheet can be simplified if a first guide surface extending away from the adhesive surface is connected to the first end of the third groove wall and / or a second guide surface extending away from the adhesive surface is connected to the second end of the first groove wall for inserting the guide sheet. Thus, the guide surface(s) control and assist the insertion of the twisted guide sheet. This guide surface(s) can be suitably rounded or angled according to the insertion direction.

[0015] For the insertion of the guide bow, it is particularly advantageous if the opening and the recess, with any appropriately inclined guide surfaces present, are designed in such a way that the guide bow can be inserted through the opening into the recess after twisting against the desired torque direction by 10 - 45°, in particular by 15 - 30°.

[0016] The treatment, and in particular the application of the intended torque and / or force, can be carried out with particular precision if the first groove wall section and the second groove wall section are designed to serve as contact surfaces for the guide arch, transmitting torque and / or force from the guide arch to the bracket. In addition, the third groove wall and the groove base section can also serve as such contact surfaces.

[0017] For the insertion of the guide arch, it may be advantageous if the groove base section is aligned at an angle between 75° and 90° to the first groove wall section and the second groove wall section is aligned at an angle between 90° and 115° to the third groove wall.

[0018] If the distance between the groove base and the third groove wall corresponds to the distance between the first and second groove wall sections, a guide arch with a square cross-section can be used particularly efficiently for treatment. Additional options for orthodontic treatment arise when a through-hole is provided through the body, running parallel to the groove-shaped recess, between the adhesive surface and the outer surface, and can be used to attach additional treatment elements. Multiple through-holes can also be provided.

[0019] If the adhesive surface has a substantially trapezoidal, rectangular or parallelogram-shaped base, the bracket can be bonded to the tooth particularly quickly, precisely and securely.

[0020] According to an advantageous embodiment, the bracket body has rounded corners and edges, so that the bracket is also optimized as an attachment for orthodontic aligner therapy. The transition from the groove-shaped recess to the outer surface is also preferably rounded. The brackets are also characterized by a very flat, slightly conical shape and are therefore ideally suited as attachments for subsequent orthodontic aligner treatment for fine adjustment of the respective dental arches and occlusion. The adhesive side facing the tooth can be adapted to the rounded labial and buccal tooth morphology. A micro-retentive surface design can also be used here to achieve the best possible bond to the luting resin with which the bracket is bonded to the respective tooth.In addition, additive 3D ceramic precision printing also allows for individual design of the surface design of the bonding surface to the tooth according to the actual tooth surface morphology.

[0021] Further advantages, features, and special features of the invention will become apparent from the following description of advantageous, but non-limiting, embodiments of the invention with reference to the schematic and not necessarily to scale drawings. They show:

[0022] Fig. 1a to Fig. 1c show various schematic views of a bracket according to the invention, namely front view, side view from the left and top view, respectively, with a groove-shaped recess;

[0023] Fig. 2 is a greatly enlarged view of Fig. 1a for a clearer illustration; Figs. 3a and 3b are side views of further embodiments; and

[0024] Fig. 4a to 4h show different stages during the insertion of a guide arch into the groove-shaped recess.

[0025] To facilitate further explanation, directional and orientation information refers, without any restriction, to an adhesive surface of the bracket facing downwards, exemplified here as horizontal, to the tooth surface. Figs. 1a to 1c and Fig. 2 show an embodiment of the bracket 10 according to the invention, wherein Figs. 1a and 2 show an adhesive surface 12 for attachment to a tooth surface (not shown) at the bottom. In Fig. 2, reference numeral 8 denotes a reference plane, such as the occlusal plane or the gingival plane, which is approximately horizontal in a standing person with a natural head posture.For simplicity of illustration, it is assumed below that the reference plane 8 coincides with the occlusal plane, which, as shown, is equivalent to a guide bow—as described in more detail later—being inserted from the occlusal plane into a groove-shaped recess 20 (also called a groove, slot, or bracket slot) of the bracket 10. If the reference plane 8 coincides with the gingival plane, the guide bow would thus be inserted from the gingival plane into the groove-shaped recess. Although not shown in detail, the reference plane 8 can be inclined by up to ± 45° relative to the occlusal or gingival plane. The more precise structure of the bracket 10 according to the invention is explained primarily with reference to Fig. 2. Starting from the adhesive surface 12 shown below, an outer surface 14 extends and encloses a bracket body 11.In the right half of the bracket 10, the groove 20 is provided, running parallel to the reference plane 8, which is accessible via an opening 60 indicated by dashed lines for inserting a guide arch 70 shown later (see, for example, Fig. 3). The groove 20 consists of a groove base 22, running parallel to the adhesive surface 12 here, a first groove wall 32 shown on the right, a second groove wall 42 shown on the left, and a third groove wall 52 partially closing the groove 20 at the top and leaving the opening 60 free. Between the groove-shaped recess 20 and the left edge of the outer surface 14, a through-bore 80 is provided, which penetrates the body 11 and extends essentially parallel to the recess 20 and serves to fasten additional elements.

[0026] The first groove wall 32 has a first, lower end 33 and a second, upper end 34. A first, right-hand end 23 of the groove base 22 adjoins the first end 33 of the first groove wall 32, and a first, lower end 43 of the second groove wall 42 adjoins the second, left-hand end 24 of the groove base 22. A second, left-hand end 54 of the third groove wall 52 adjoins a second, upper end 44 of the second groove wall 42. The other, first and thus right-hand end 53 of the third groove wall 52, together with the second end 34 of the first groove wall 32, defines the opening 60.

[0027] Adjacent to the first end 53 of the third groove wall 52 is a first guide surface 58, which extends diagonally upwards and away from the adhesive surface 12 or the groove 20. In addition, adjoining the second end 34 of the first groove wall 32 is a curved or rounded second guide surface 38, which also extends diagonally upwards and away from the adhesive surface 12 or the groove 20. These two guide surfaces 38, 58 serve to facilitate the insertion of the previously twisted guide arc 70, for example with a rectangular cross-section, which in the example shown here occurs in an angular range of 15 to 25° with respect to the reference plane 8. In order to enable the complete insertion of the guide arch 70 obliquely to the groove 20, a wall-side recess 48 is provided in the lower region of the second groove wall 42 and a groove-base-side recess 28 is provided in the right half of the groove base 22.After the guide arch is released, its twisting is released, and the guide arch comes into contact with a first groove wall section 36 of the first groove wall 32 and a second groove section 46 of the second groove wall 42. Via these two groove wall sections 36, 46, the guide arch can then exert the desired rotation for orthodontic treatment on the tooth provided with the bracket 10 by applying a corresponding torque. In the region of the second end 34 of the first groove wall 32, a further groove wall section 37 is provided, which in this embodiment is a straight continuation of the first groove wall section 36, but whose precise design can generally be varied.

[0028] In Fig. 1a and Fig. 2, the recess 28 on the groove base side and the recess 48 on the wall side are shown with respective straight surfaces. Instead, however, curved or rounded recesses 28 and 48 can also be provided, as shown in Fig. 3a for a guide arch 70 with a square cross-section. An arrow indicates how the guide arch 70 rotates counterclockwise when it is released after being inserted into the groove 20 and can be released from its twist. The guide arch 70 then rests against the first groove wall section 36 and the second groove wall section 46 and can exert the desired counterclockwise torque on the bracket 10 and thus the tooth. Fig. 3b, on the other hand, shows the situation in which the guide arch 70 is inserted into the groove and rotates clockwise, which is also indicated by an arrow.This rotation is facilitated by a rounded recess 29 on the groove base side in the region of the left end 24 of the groove base 22 and a rounded recess 49 on the wall side in the region of the second end 44 of the second groove wall 42. Here, the guide arch 70 rests against a groove base section 26 and the third groove wall 52 and can exert the desired clockwise torque on the bracket 10.

[0029] Figs. 3a and 3b each schematically show a square slot with slot dimensions of 0.5588 x 0.5588 mm (equivalent to .022 x .022 inch) with opposing torque orientation and maximum slot-to-arc fit, and the resulting pronounced recesses on the surfaces opposite the insertion corner. In Fig. 3a, a counterclockwise torque is generated, while in Fig. 3b, a clockwise torque is generated against the adhesive surface 12 indicated downwards on the tooth to be bonded. The more precisely the guide arch 70 fits into the groove 20, ie the more groove-filling the guide arch 70 is to be, the more pronounced the corresponding groove-base-side recess 28 and the wall-side recess 48 must be provided on the surfaces opposite the opening 60, ie on the groove base 22 and on the second groove wall 32, which are geometrically adapted to the respective insertion direction running obliquely to the groove 20.However, it is important that the surfaces active for the desired torque development, i.e. the first groove wall section 36 and the second groove wall section 46 or the groove base section 26 and the third groove wall 52, remain untouched.

[0030] Since each tooth can be activated with a torque in the longitudinal cross-section of the bracket in two opposing directions of rotation, there are differently designed recesses for each direction of rotation. This means that before the bracket is bonded, the torque direction of the bracket must be determined and set to a torque effect, although this is generally not a problem clinically. Fig. 4a shows an enlarged scale of the groove 20, into which the guide bow 70 can be inserted along the guide surfaces 58 and 38 through an indicated opening 60. The following Figs. 4b to 4g show successive stages of inserting the guide bow 70, which is shown in dashed lines, into the groove 20. In Fig. 4b, the guide bow 70 can be seen in a position approximating the groove 20, and in Fig.In Fig. 4c, the guide arch 70 is already twisted clockwise by a certain angle—which represents merely an intermediate stage. In Fig. 4d, the guide arch 70 is then twisted to such an extent that one side surface rests against the first guide surface 58, while its other side surface is not far from the second guide surface 38. The guide arch 70 is held in this twist and can then be inserted into the groove 20 in a translational movement until it reaches the position shown in Fig. 4e, in which it engages both the recess 28 in the groove base and the recess 48 in the wall. As soon as the guide bow 70 is released or twisted in the opposite direction to the twisting, it "relaxes" and moves from the position shown in Fig. 4f to the position shown in Fig. 4g, in which it engages neither in the recess 28 on the groove base side nor in the recess 48 on the wall side.Since the remaining twist still exerts a torque opposite to the direction of the original twist, the guide arch 70 continues to rotate until it comes into contact with the first groove wall section 36 and the second groove wall section 46, exerting the desired torque on the bracket 10 and thus also on the tooth bonded thereto. Fig. 4h thus shows the orthodontic guide arch 70 in the final position with active counterclockwise torque.

[0031] As is currently common with all programmed, so-called straight-wire brackets, the ligation-free bracket slot (i.e. groove 20) can be freely aligned three-dimensionally in the bracket body in both torque alignment (the rotation in the bracket's longitudinal cross-section) and angulation according to the bracket prescription, thus ensuring compatibility with almost all fixed orthodontic treatment philosophies.

[0032] The brackets according to the invention, with a ligation-free bracket slot, are primarily designed for ceramic injection molding and 3D ceramic precision printing, but can also be printed stereolithographically in a 3D printer using a ceramic-filled plastic hybrid material. Aluminum oxide (AL2O3) or zirconium oxide (ZrO2) is used as the material. A ceramic-filled plastic hybrid material suitable for use with special resin printers is also possible. Production in conventional stainless steel is also possible, although this may be perceived as less aesthetically pleasing.

[0033] As already mentioned, the ligation-free bracket slot is shown on the right-hand side in the occlusal tooth direction with the opening facing upwards to the right. The slot dimensions of 0.5588 x 0.7112 mm (equivalent to .022 x .028 inch) are designed to accommodate a guide wire measuring 0.4826 x 0.635 mm (equivalent to .019 x .025 inch) and are widely used in modern fixed orthodontics. This ensures the necessary tolerances for problem-free insertion of the guide wire and the play of the guide wire in the slot, as the tooth must be able to move along the guide wire. The same applies to guide wires with a square cross-section. The active torque direction is counterclockwise; the limiting surface during insertion, or guide surface 38 and / or 58, is angled 20 degrees relative to the slot depending on the insertion direction.

[0034] In the above embodiments, the third groove wall is substantially parallel to the groove base or the groove base section. It is understood that deviations from this can also be advantageous. Furthermore, grooves, bead-like, or dome-like projections can be provided on the first and second groove walls, on which the inserted guide arch can rest and which can reduce the friction of the guide arch in the slot.

[0035] It should be noted that the features of the invention described with reference to individual embodiments, such as the position and orientation of the groove-shaped recess and the surfaces bounding it, may also be present in other embodiments, unless otherwise stated or technically prohibited. Furthermore, such features of individual embodiments described in combination do not necessarily always have to be implemented in a given embodiment.

[0036] LIST OF REFERENCE SYMBOLS

[0037] 8 Reference plane

[0038] 10 Bracket

[0039] 11 Bracket body

[0040] 12 Adhesive surface Outer surface Groove-shaped recess / slot Groove base First end of the groove base Second end of the groove base Groove base section , 29 Groove base-side recess First groove wall First end of the first groove wall Second end of the first groove wall First groove wall section Further groove wall section Second guide surface Second groove wall First end of the second groove wall Second end of the second groove wall Second groove wall section , 49 Wall-side recess Third groove wall First end of the third groove wall Second end of the third groove wall First guide surface Opening Guide arc Through hole

Claims

PATENT CLAIMS:

1. Bracket (10) for orthodontic treatment with a fixed treatment technique, comprising a body (11) having: an adhesive surface (12) for adhesive attachment to a tooth; an outer surface (14) adjoining the adhesive surface (12); and a groove-shaped recess (20) provided in the outer surface (14), which runs parallel to a reference plane (8) corresponding to the occlusal plane or the gingival plane or is inclined by up to + 45° thereto, wherein the groove-shaped recess (20) is delimited by: - a groove base (22) facing the adhesive surface (12) and comprising a groove base section (26) with a first end (23) facing the reference plane (8) and a second end (24) facing away from the first end (23), - a first groove wall (32) with a first end (33) facing the adhesive surface (12) and a second end (34) facing away from the first end (33), which adjoins the first end (23) of the groove base (22) at its first end (33) and has a first groove wall section (36) which runs parallel to the reference plane (8), - a second groove wall (42) with a first end (43) facing the adhesive surface (12) and a second end (44) facing away from the first end (43), which adjoins the second end (24) of the groove base (22) at its first end (43) and has a second groove wall section (46) running approximately parallel to the first groove wall section (36), wherein the second groove wall (42) extends further away from the adhesive surface (12) than the first groove wall (32), and - a third groove wall (52) with a first end (53) facing the reference plane (8) and a second end (54) facing away from the first end (53), which integrally and dimensionally stable adjoins the second end (44) of the second groove wall (42) at its second end (54) and extends less far towards the reference plane (8) than the groove base (22), wherein an opening (60) for inserting and removing an elastically twistable, spring-elastic guide arch (70) remains between the second end (34) of the first groove wall (32) and the second end (54) of the third groove wall (52) after corresponding twisting of the guide arch (70), wherein the guide arch (70) has a rectangular, square or parallelogram-shaped cross-section, and wherein both the first groove wall section (36) and the second groove wall section (46) as well as the third groove wall (52) and the groove base section (26) serve as areas that after resetting the twist of the guide bow (70) cause it to lock automatically in the recess (20).

2. Bracket (10) according to claim 1, wherein either a groove base-side recess (28) is provided in the region of the first end (23) of the groove base (22) and a wall-side recess (48) is provided in the region of the first end (43) of the second groove wall (42), or a groove base-side recess (29) is provided in the region of the second end (24) of the groove base (22) and a wall-side recess (49) is provided in the region of the second end (44) of the second groove wall (42).

3. Bracket (10) according to claim 2, wherein in the groove base-side recess (28, 29) and in the wall-side recess (48, 49) fillets are provided which facilitate the complete insertion of the guide arch (70) and the resetting of the twist of the guide arch (70).

4. Bracket (10) according to one of the preceding claims, wherein a first guide surface (58) extending away from the adhesive surface (12) adjoins the first end (53) of the third groove wall (52) and / or a second guide surface (38) extending away from the adhesive surface (12) for inserting the guide arch (70) adjoins the second end (34) of the first groove wall (32).

5. Bracket (10) according to one of the preceding claims, wherein the opening (60) and the recess (20) are designed such that the guide arch (70) can be inserted into the recess (20) through the opening (60) after twisting by 10 - 45°, in particular by 15 - 30°.

6. Bracket (10) according to one of the preceding claims, wherein either the first groove wall section (36) and the second groove wall section (46) and optionally the third groove wall (52) and / or the groove base section (26) serve as surfaces for transmitting force and / or torque from the guide arch (70) to the bracket (10).

7. Bracket (10) according to one of the preceding claims, wherein the groove base section (26) is aligned at an angle between 75° and 90° to the first groove wall section (36) and the second groove wall section (46) is aligned at an angle between 90° and 115° to the third groove wall (52).

8. Bracket (10) according to one of claims 1 to 6, wherein the distance of the groove base section (26) to the third groove wall (52) corresponds to the distance between the first groove wall section (36) and the second groove wall section (46).

9. Bracket (10) according to one of the preceding claims, wherein a through-bore (80) is provided which penetrates the body (11) and runs parallel to the groove-shaped recess (20) and runs between the adhesive surface (12) and the outer surface (14).

10. Bracket (10) according to one of the preceding claims, wherein the adhesive surface (12) has a substantially trapezoidal, rectangular, or parallelogram-shaped base area.

11. Bracket (10) according to one of the preceding claims, characterized in that it has rounded corners and edges so that it is optimized as an attachment for an orthodontic aligner.

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