Self-ligation bracket for orthodontics

Abstract

To provide a self-ligating bracket for orthodontics.SOLUTION: A self-ligating bracket 1 comprises a clamp 25 that is resilient and comprises a first clamp leg and a second clamp leg 27, which are connected with an occlusally or gingivally arranged clamp bend 28. The first clamp leg is inserted into a slit and can be moved in the gingival-occlusal direction between a closed and open position of the clamp. The clamp has an access opening 40 for engagement of a bracket opener in the region of the clamp bend. In a view along the longitudinal direction of the first clamp leg or in a top view of the clamp unwound into a plane, the access opening is delimited laterally by two arms 43 and 44 running in a V-shape towards each other. A distance measured from mesial to distal between the two arms is at least as large as the arm width of each of the two arms measured from mesial to distal.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a self-ligating bracket for orthodontics having the features shown in the preamble of claim 1.

Background Art

[0002] Such brackets are known from Patent Document 1. This bracket includes an elastic clamp having two clamp legs and a clamp bend connecting the two clamp legs. At the bend of the clamp, the clamp has a constant width in the mesial-distal direction and has a circular access opening for engaging a bracket opener. Due to the access opening, the cross-section of the clamp becomes weak, and the strength of the clamp may be impaired. The spring force of the clamp may decrease over time. Also, the clamp may break at the portion where the cross-section is weakened by the access opening. In either case, the bracket ceases to function.

[0003] From Patent Document 2, a non-ordinary bracket is known, which also consists of an elastic clamp having two clamp legs and a clamp bend connecting the two clamp legs. However, the access opening for engaging the bracket opener is located on the second clamp leg that bears little bending stress. Plaque may accumulate in the depressions and recesses of the bracket over time. Especially when plaque accumulates in the slit into which the first clamp leg is inserted, it may prevent the clamp from being moved to the open position. After a while, when replacing the arch wire passing through the groove, if the movement of the first clamp leg is sluggish or blocked, it is very likely that the bracket opener engages with the second clamp leg, causing the clamp to be bent unintentionally. Such a bracket can no longer perform its function properly.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The object of the present invention is to improve the bracket of the type described at the beginning.

Means for Solving the Problems

[0006] This object is achieved by a bracket having the features defined in claim 1. Advantageous embodiments of the present invention are the subject matter of the dependent claims.

[0007] The self-ligating bracket for orthodontics according to the present invention comprises a base, an occlusal wall extending from the base, a gingival wall extending from the base, a groove separating the occlusal wall and the gingival wall and continuously extending in a direction from mesial to distal, and the bracket-side surface facing the opposite side of the groove is called a fixed side surface prepared to be adhesively bonded to a tooth. The bracket according to the present invention can bond its fixed side surface to the lingual surface or the vestibular surface of a tooth. In technical terms, the groove is also called a "slot" and is used to hold an archwire. The archwire usually passes through a series of brackets attached to a series of adjacent teeth. By pulling or twisting the archwire, pretension is generated in the wire and transmitted from the archwire to the bracket and from the bracket to one or more teeth, thereby changing the position of the teeth.

[0008] The bracket has a slit extending in the gingival-occlusal direction. This slit can be delimited by a lingual guiding surface and a labial guiding surface. The bracket further has an elastic clamp, and this clamp has a first clamp leg and a second clamp leg connected to each other by a curved portion.

[0009] This curved portion is substantially C-shaped and is hereinafter referred to as the clamp bending portion. The clamp bending portion can be arranged on the occlusal side or the gingival side according to the direction in which the bracket is adhered to the tooth surface. In the case of a bracket whose fixed surface is intended to be adhered to the vestibular surface of the tooth, the first clamp leg is also called the lingual leg, and the second clamp leg is also called the labial leg.

[0010] The first clamp leg has a longitudinal direction in the gingival-occlusal direction and extends in a plane. The first clamp leg is inserted into the slit and is movable in the gingival-occlusal direction between the closed position and the open position of the clamp. The longitudinal direction of the first clamp leg coincides with the displacement direction. The first clamp leg can be guided between the lingual surface and the labial surface of the slit.

[0011] In an embodiment, when the clamp is moved from the gingival side to the occlusal side to be opened, the clamp bending portion is arranged on the occlusal side. In this case, the second clamp leg extends into the notch of the gingival wall at the closed position of the clamp.

[0012] At the open position of the clamp, the tip of the second clamp leg hangs on the occlusal wall, and the arch wire can be inserted into or removed from the groove. At the closed position, the second clamp leg closes the groove and elastically rests against the arch wire to press the arch wire against the bottom surface of the groove.

[0013] Therefore, such a bracket is called an "active bracket". When the arch wire applies a force exceeding the restoring force of the clamp to the second clamp leg, the arch wire can apply a sufficiently large force to the second clamp leg so that the notch of the gingival wall can be restricted by the stop based on the contact of the second clamp leg.

[0014] This stop limits the distance of the second clamp leg from the bottom of the groove. The stop on the gingival wall of the bracket also limits the maximum possible dimension of the arch wire in the labiolingual direction. Alternatively, the clamp can be opened by moving it from the occlusal side to the gingival side. In such a case, the clamp bend is arranged on the gingival side, and the second clamp leg extends into the notch in the occlusal wall in the closed position and its tip rests on the gingival wall in the open position.

[0015] In the case of a clamp bend arranged on the occlusal surface, the clamp is held in the closed position by the second clamp leg being spring-pressed against the occlusal wall when pushed into the closed position, and can only be moved from the closed position to the open position by elastic bending. In the case of a clamp bend arranged on the gingiva, the second clamp leg is spring-biased against the gingival wall.

[0016] The clamp of the bracket according to the invention comprises an access opening in the clamp bend for engaging a bracket opener. The bracket opener is a tool for opening the clamp. The bracket opener can have a handle and an access end, in particular a cylindrical access end, for engaging the access opening of the clamp.

[0017] As the bracket opener, a probe normally used by a dentist to examine the tooth surface can also be used. Accordingly, the access opening can also be called a probe access opening. The access end of the bracket opener can be inserted into the access opening to move the clamp from the closed position to the open position.

[0018] The first clamp leg can be configured to prevent accidental loss of the clamp. Due to the interaction between the first clamp leg and the other parts of the bracket, the clamp cannot be moved beyond its open position in the bending directions towards the occlusal side or the gingival side of the clamp, respectively.

[0019] The corresponding embodiments of the first clamping leg are known, for example, from Patent Document 1 and Patent Document 2 described at the beginning. Pushing the first clamping leg out of the slit is restricted so that the clamp does not fall out of the slit.

[0020] According to the present invention, the access opening is laterally delimited in a view along the longitudinal direction of the first clamping leg or in a top view with the clamp unwound onto a plane by two arms running in a V-shape towards each other. One of the two arms is in contact with the access opening on the proximal side thereof. The other arm is in contact with the access opening on the distal side. The distance between the two arms measured in the proximal-distal direction is at least as large as the arm width of each of the two arms measured in the proximal-distal direction. The arm width of each of the two arms can be half of the width of the clamp bending part in the region outside the access opening.

[0021] Each arm can have a linearly extending segment. The width of each of the two arms can be at most the same as the maximum distance between the two arms. The distance between the two arms can be at least 0.7 mm. The predetermined dimensional specifications and dimensional ratios refer to the respective nominal dimensions, which can vary within the range of normal manufacturing tolerances.

[0022] The cross-section of the clamp at the clamp bending part greatly influences the spring characteristics of the clamp. There is a maximum value in the clamp cross-section of the clamp bending part, which is hereinafter referred to as the "maximum cross-section". The cross-section of the clamp at the clamp bending part also has a minimum value, which is hereinafter referred to as the "minimum cross-section".

[0023] Each arm has an arm cross-section in the region of the access opening. This cross-section is the area of the cut surface of the clamp cut along the longitudinal direction of the groove at each position. In the case of a rectangular clamp cross-section, the cross-section can be calculated by multiplying the thickness and width of the clamp. The sum of the cross-sections of the two arms measured at one point of the clamp bending part is less than 10%, particularly less than 6%, smaller than the minimum cross-section.

Advantages of the Invention

[0024] The present invention has great advantages.

[0025] Since the two arms form a V shape with each other, a rectangular access opening is formed. Since the width of this opening is large near the second clamp leg, it is easy to insert the bracket opener.

[0026] At the same time, the two arms running in a V shape with each other exert a centering effect on the bracket opener. As a result, the bracket opener is centered in the centripetal - centrifugal direction during the opening process and is positioned at the center of the clamp.

[0027] Due to the rectangular access opening, the access opening can be brought closer to the first clamp leg. Therefore, the access opening can be arranged at the clamp bending part very close to the base of the bracket. As a result, the opening force exerted by the bracket opener can be made to act almost in the middle of the two clamp legs.

[0028] By applying force at the center, the force exerted by the bracket opener on the clamp is optimized. In the initial stage of opening the legs, since the opening force is evenly distributed to both clamp legs, even a clamp that has become sluggish due to dirt can be opened without being distorted.

[0029] Due to the centering effect of the two arms, the force point of the bracket opener can move even closer to the first clamp leg during the opening process. As a result, a large proportion of the opening force acts on the first clamp leg rather than the second clamp leg. The movement of the first clamp leg often becomes sluggish throughout the movement path due to plaque deposition, while for the second clamp leg, there is no significant dulling in the further progress of the opening movement after overcoming the initial obstacle. This makes the opening of the clamp even easier.

[0030] The present invention can ensure that, except for manufacturing tolerances, the total cross-section of the arm matches the cross-section of the clamp in the area of the clamp bend outside the access opening. This also applies if the width of each of the two arms is half of the minimum width of the clamp bend outside the access opening.

[0031] The access opening in the area of the clamp bend, where the clamp is most stressed by bending stress, can prevent the clamp from becoming weak. Since the two arms extend in a V-shape with respect to each other, the width of the clamp can be increased at the clamp bend without changing the cross-section of the clamp.

[0032] The cross-section of the clamp that determines the spring effect can be kept substantially constant throughout the entire clamp bend. As a result, a uniform bending behavior can be obtained over the entire clamp bend, improving the bending behavior and spring characteristics of the clamp.

[0033] The clamp according to the present invention has very high stability, fatigue strength, and good cycle resistance. Considering 240,000 chewing cycles per year in the patient's oral cavity, this means that the spring force does not significantly decrease even during a usage period of more than 18 months. Furthermore, breakage of the clamp due to material fatigue can be avoided.

[0034] The clamp can be made very easily from sheet metal. The rectangular access opening can be made very easily, for example, by punching, before bending. Except for the clamp bend between the two clamp legs, no plastic deformation is required during the manufacture of the clamp.

[0035] In a further embodiment of the clamp, the angle between the two arms can be in the range of 40° to 75°, particularly in the range of 45° to 70°. One of the arms can run at an angle within the range of 20° to 45°, particularly within the range of 23° to 33°, with respect to the longitudinal direction of the clamp in a top view of the clamp wound back onto a plane. The aforementioned angle of the arm can be measured particularly with respect to the longitudinal direction of the first clamp leg. In addition to the aforementioned angle ranges, the possible angles of the bracket need to be considered.

[0036] In one embodiment, the oval access opening can extend over at least 50%, particularly at least 55%, of the clamp bend. The rectangular access opening can extend over a bending angle of the clamp bend of at least 100°, particularly at least 120°. In particular, when the total bending angle is 200° or more, the access opening can extend over a bending angle of at least 125°.

[0037] The term "total bending angle" means the total bending angle of the clamp bend from the first clamp leg to the second clamp leg. A segment of the clamp bend where the two arms run in a V-shape with respect to each other can be adjacent to a segment of the clamp bend where the two arms run parallel to each other. A segment where the two arms extend parallel to each other can be adjacent to the second clamp leg. Each arm can extend with a substantially constant arm width over a segment of the clamp bend. As a result, the rectangular access opening can be made large enough to extend over a particularly large bending angle of the clamp bend.

[0038] In a further embodiment, the maximum cross-section can be made 20% or less larger than the minimum cross-section. The cross-sections of the two arms differ by only 10% or less at one point of the clamp bend. Furthermore, the change in the cross-section of the arm along the course of the arm can be 10% or less for each arm.

[0039] For example, in the case of a clamp having a certain thickness, this is ensured if the nominal width of each of the two arms is within a tolerance of ±5%. In particular, segments of the clamp bending part with a cross-section larger than the minimum cross-section by more than 10% can only extend to a bending angle of 20% or less of the total bending angle of the clamp bending part, and in particular not exceeding 30°.

[0040] By taking these measures individually, and in particular in combination with each other, it is possible to cover cross-sectional changes due to manufacturing tolerances. Since the cross-section of the clamp bending part can be kept constant within a narrow range, it is possible to achieve a particularly uniform bending behavior over the entire clamp bending part. Nevertheless, the overall width of the clamp can increase by more than 50%, in particular between 50% and 70%, in the region of the clamp bending part compared to the width of the first clamp leg. Furthermore, a transition radius can be provided between different clamp segments to avoid an acute transition, for example from a segment containing an arm running in a V-shape to a segment without an access opening.

[0041] In the case of a series of self-ligating brackets for dental orthodontics consisting of a number of brackets according to the invention, it is possible to make the nominal dimension of the minimum cross-section of the clamp in the region of the clamp bending part the same for all brackets of the series. The minimum cross-section of one of the series of brackets can differ by no more than 10% from the respective minimum cross-sections of the other brackets of the series. This means that it is also possible to achieve a particularly uniform bending behavior over the entire series of brackets to which the brackets adhered to the patient's dental arch are selected. Thereby, a uniform state can be achieved along the entire arch wire.

[0042] The clamp bending part can have a center when viewed in a longitudinal section passing through the first clamp leg. If the clamp is bent with a uniform bending radius in the region of the clamp bending part, this center is the center point of the bending radius, and the bending angle is the corresponding central angle. If the bending radius is not uniform, the bending angle can be measured by analogy around the approximate center of the clamp bending part.

[0043] The center of the clamp bending part can be at a first height H1 above the first clamp leg when viewed in a longitudinal section passing through the first clamp leg. The end of the access opening facing the first clamp leg can be located at a second height H2 above the first clamp leg. The second height H2 can be within a range delimited by the first height reduced by 20% and the first height increased by 20%. Thus, the second height H2 can be in the range from 0.8*H1 to 1.2*H1. In particular, the second height H2 can be in the range of the first height H1 ± 0.1 mm (H1 ± 0.1 mm). As a result, the application of force to the center of the bracket opener can be ensured particularly well, and the opening force is particularly evenly distributed to both legs at the start of the opening process.

[0044] In a further embodiment, the bracket can have a widened base on its fixed side, the width of which is larger than the corresponding width of the base measured from the mesial to the distal and / or from the gingiva to the occlusion.

[0045] Such a widened base, also known as a "pad", increases the area available for adhering the bracket on the fixed side, thereby improving the adhesion between the bracket and the tooth.

[0046] Also, on the fixed side, structures such as undercut protrusions with alternating orientations can be provided, which significantly improves the adhesion between the bracket and the tooth when the bracket is adhered to the tooth. In the case of a metal bracket, the pad can also be manufactured separately and then connected to the bracket base by welding.

[0047] The occlusal wall can have at least one occlusal ligation wing. The gingival wall can have at least one gingival ligation wing. The ligation wire can be attached to the ligation wing by a method known per se.

[0048] The wall assigned to the clamp bending part can form a recess at its end that is away from the bottom surface of the groove when viewed along the longitudinal direction of the first clamp leg.

[0049] The recess can receive the second clamp leg and / or the clamp bending part of the clamp in the closed position. When the clamp is open, the second clamp leg can fit into the recess. Thereby, the guidance during the opening and closing of the clamp can be improved. Furthermore, the comfort during the patient's bracket attachment can be enhanced. The depth of the recess can be at least 80% of the thickness of the clamp.

[0050] The slit into which the first clamp leg is inserted can extend transversely to the groove, particularly perpendicular to the groove. In particular, the slit can extend continuously through the base, for example, in the form of a passage. Alternatively, the slit can close on the side of the bracket facing away from the clamp bending part, and in this case, particularly on the gingival side of the bracket.

[0051] The slit can pass through the base between the groove and the fixed side surface of the bracket. In particular, the bottom of the groove can extend continuously from the mesial to the distal without interruption. As a result, there is no passage between the slit and the groove. Thereby, the manufacturing of the bracket, particularly a single-piece bracket, can be simplified. Furthermore, there is less free space inside the bracket that may be clogged by deposits.

[0052] In a further embodiment, the bracket can have a support surface for the bracket opener. The support surface faces the clamp bending part. The support surface is inclined with respect to the first clamp leg. The support surface can extend at an angle of 60° - 85°, particularly 70° - 80°, with respect to the first clamp leg. The inclined support surface facilitates the opening of the clamp by the bracket opener.

[0053] The groove of the bracket can have inclined surfaces and / or curvatures at its centrifugal end and its centripetal end. Two ribs can be provided on the wall facing the clamp curvature, particularly the occlusal wall, of the groove, and these ribs extend in the linguolabial direction. The ribs can have chamfered edges or rounded edges.

[0054] Due to the ribs, it is very easy to finely adjust the width of the groove measured in the gingivo-occlusal direction when manufacturing the bracket. The bracket can have rounded edges.

[0055] Further details and advantages of the present invention are described using exemplary embodiments of the present invention with reference to the accompanying drawings. Corresponding reference numerals are assigned to identical components and corresponding components.

Brief Description of the Drawings

[0056]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Mode for Carrying Out the Invention

[0057] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Example

[0058] FIGS. 1 to 5 show exemplary embodiments of a bracket 1 according to the present invention. The bracket 1 according to the present invention consists of a curved fixed side surface 2, the curvature of which approximates the vestibular surface of a tooth (not shown). On the fixed side surface 2, protrusions 3 are arranged in a row. An adhesive for adhering the bracket 1 to the vestibular side of the tooth can be applied on the fixed side surface 2.

[0059] In this way, the fixed side surface 2 forms the lingual side of the bracket 1. In the case of a bracket adhered to the lingual side of a tooth, the terms "lingual side" and "labial side" must be exchanged accordingly.

[0060] The bracket 1 consists of a base 4, from which a gingival wall 5 and an occlusal wall 6 extend. These two walls 5, 6 extend parallel to each other, extend linearly from the distal to the mesial, and are separated by a groove 7 that opens in the labial direction.

[0061] The gingival wall 5 is provided with two ligation wings 8 protruding in the gingival direction. The occlusal wall 6 is provided with two ligation wings 9 protruding in the occlusal direction.

[0062] Therefore, in FIG. 4, the directions for attaching the bracket to the tooth are as follows with respect to the sublingual direction, supra-labial direction, right occlusal direction, left gingival direction, and centripetal - centrifugal direction perpendicular to the drawing plane.

[0063] The groove 7 has a rectangular cross-section and is used to accommodate an arch wire (not shown) that is not part of the bracket. By applying prestress to the arch wire, torque can be applied to the bottom 11 of the groove 7 and the walls 5 and 6.

[0064] For this purpose, the clear cross-section of the groove 7 is basically rectangular. In this case, it is delimited by the bottom 11 of the groove 7 and two ribs 12 on the occlusal wall 6, and serves to reduce the friction of the arch wire within the groove 7.

[0065] The bottom 11 extends continuously without interruption from the centripetal to the centrifugal. At both ends of the groove 7, there are provided inclined surfaces 14 with rounded bottoms on the bottom 11, inclined surfaces 15 with rounded bottoms on the gingival wall 5, and inclined surfaces with rounded bottoms on the occlusal wall 6, which also serve to widen the entrance of the groove 7 and reduce the friction of the arch wire lying across the groove 7. This is particularly advantageous in cases of large tooth displacements that require an irregular course of the arch wire.

[0066] Below the bottom 11 of the groove 7, a slit 18 runs parallel to the bottom 11. This slit 18 is delimited by the lingual side 19, the labial side 20, and two narrow side walls 21. The side walls 21 are parallel to each other and extend between the lingual side 19 and the labial side 20. The slit 18 extends continuously through the base 4 and is not connected to the groove 7.

[0067] The brackets 1 in FIGS. 1 to 5 include a spring clamp 25 shown separately in FIGS. 6 to 9. This is cut out from a flat sheet metal of a certain thickness D into the shape shown in FIG. 9 and bent. It has a straight first clamp leg 26 and a short second clamp leg 27 running almost straight. The first clamp leg 26 is the lingual leg, and the second clamp leg 27 is the labial leg.

[0068] The two clamp legs 26, 27 are connected by a substantially arcuate portion called the clamp bend 28. In the case shown, the clamp bend 28 forms a segment located on the occlusal side of the clamp 25. In the case of a bracket adhered to teeth in the opposite direction, the clamp bend 28 can form the gingival segment of the clamp 25, and the designations "occlusal" and "gingival" should be exchanged accordingly.

[0069] The first clamp leg 26 fits into the slit 18 with little play. The second clamp leg 27 has a width measured from mesial to distal, which substantially corresponds to the length of the groove 7 within the bracket. It is not parallel and forms an acute angle with the first clamp leg 26, approaching from the clamp bend 28. The clamp bend 28 has a total bending angle F of 210°.

[0070] The transition from the clamp bend 28 to the clamp legs 26, 27 is shown by dashed lines in FIG. 9. Line 26a indicates the starting portion of the first clamp leg 26, and line 27a indicates the starting portion of the second clamp leg 27.

[0071] At its free end (gingival end), the second clamp leg 27 extends towards the gingiva and has an extension 27b that angles towards the labial direction. This extension 27b is narrower in width than the second clamp leg 27 and narrower than the first clamp leg 26, so it fits into the notch 24 arranged in the gingival wall 5 with little play.

[0072] The first clamping leg 26 consists of a longitudinal direction 29 and an oval recess 30 running parallel to the longitudinal direction 29. The longitudinal direction 29 is indicated by a dotted line (see FIGS. 6 and 9). The recess 30 is designed as a rectangular hole and is located at the center of the first clamping leg 26.

[0073] A projection 31 protrudes tongue - side into the recess 30 from the lip side surface 20 of the slit 18. The lip side surface 20 is designed as a flat guiding surface of the first clamping leg 26. The projection 31 has the shape of a latching lug. The (occluding) side of the projection 31 facing the clamp bending portion 28 extends at an angle of approximately 20° with respect to the lip side surface 20. The (gum) side of the projection 31 facing away from the clamp bending portion 28 is inclined with respect to the lip side surface 20 more than the side facing the clamp bending portion 28. The projection 31 is integrally formed with the base 4.

[0074] The recess 30 is delimited at its (gum) end facing away from the clamp bending portion 28, at the free (gum) end of the first clamping leg 26, by a stopper 33 formed by a bar running from the proximal to the distal direction.

[0075] The tongue side surface 19 of the slit 18 consists of two guiding surfaces 19a, 19b for the first clamping leg 26, between which a channel 35 is arranged. The guiding surfaces 19a, 19b run parallel to the lip side surface 20. The guiding surfaces 19a, 19b and the channel 35 extend from the gum to the occluding surface over the entire length of the slit 18.

[0076] When the clamp 25 is attached, the first clamp leg 26 is inserted into the slit 18 along the longitudinal direction 29. The stopper 33 reaches the protrusion 31, and the first clamp leg 26 is elastically deformed in the tongue direction. The channel 35 forms a swiveling escape space when the stopper 33 slides over the protrusion 31 when the clamp 25 is inserted. The first clamp leg 26 is bent around its longitudinal direction 29 in the region of the stopper 33 by the guide surfaces 19a, 19b and the protrusion 31. When the stopper 33 is pushed onto the protrusion 31, the first clamp leg 26 returns to its planar initial shape. When the first clamp leg 26 is fully inserted into the slit 18, the clamp 25 is in the closed position with reference to FIGS. 1, 3, and 4.

[0077] To move the clamp 25 from the closed position to the open position, an access opening 40 is arranged in the region of the clamp bending portion 28, and this access opening 40 can be accessed using a tool (see FIGS. 10 to 12) called a bracket opener 41. The bracket opener 41 is composed of a cylindrical access end 42 for engaging with the access opening 40. The bracket opener 41 is provided with a handle (not shown) at an end away from the access end 42.

[0078] The access opening 40 is laterally bounded by the centripetal arm 43 and the centrifugal arm 44. Referring to FIG. 7 along the longitudinal direction 29 of the first clamp leg and referring to FIG. 9 which is a top view of the clamp 25 unwound in a plane, the two arms 43, 44 run in a V-shape towards each other. The two arms 43, 44 have an angle V and a distance A with respect to each other. The distance A is measured from the centripetal to the centrifugal.

[0079] The angle V is about 63° in the illustrated embodiment. In the top view of FIG. 9, the two arms 43 and 44 each extend at an angle C with respect to the longitudinal direction 29 of the clamp 25, which is half the size of the angle V. The first clamp leg 26 has a constant width B, which is 1.44 mm in the illustrated embodiment. The arm 43 has a constant width B1 that is half of the width B, and the arm 44 has a constant width B2 that corresponds to the width B1. A transition radius 45 is provided to prevent the two arms 43, 44 from becoming angled towards each other in the V-shaped region. Starting from the transition radius 45, the distance A increases as the distance from the first clamp leg 26 increases. The segment where the two arms 43, 44 run in a V-shape with respect to each other is followed by a segment of the clamp bend 28 where the two arms 43, 44 run parallel to each other and have a constant distance A. At at least one point of the clamp bend 28, the distance A between the two arms 43, 44 can be measured, and this distance A is at least as large as the widths B1 and B2.

[0080] In the illustrated embodiment, the distance A in the region of the access opening 40 facing away from the transition radius 45 is 0.96 mm. The rectangular access opening 40 extends over more than 60% of the total clamp bend 28 with a bend angle E of 126° of the clamp bend 28, and thus a total bend angle F of 210°.

[0081] The clamp bend 28 is bent with a bend radius of 0.55 mm. In the longitudinal section of the first clamp leg 26 shown in FIG. 8, the center 46 of the clamp bend 28 is thus at a height H1 of 0.55 mm from the first clamp leg 26. The end of the access opening 40 facing the first clamp leg 26, i.e., the lower end in FIGS. 7 and 8 delimited by the transition radius 45, is located at a second height H2 above the first clamp leg 26. The second height H2 is in the range delimited by the first height reduced by 10% (0.9*H1) and the first height increased by 10% (1.1*H1). Thus, according to this calculation rule (H1±10%), the range of the second height H2 is from 0.495 mm to 0.605 mm.

[0082] The second height (H2) may be within a range delimited by the first height reduced by 20% (0.8*H1) and the first height increased by 20% (1.2*H1).

[0083] In FIG. 5, a cut surface of the intersecting clamp 25 is shown, and this cut surface shows the respective cross-sections of the clamp 25.

[0084] In the illustrated embodiment, the sum of the arm cross-sections of both arms 43, 44 coincides with the cross-section of the first clamp leg 26. Since the thickness D of the clamp 25 is constant, the minimum cross-section in the region of the clamp bending portion 28 outside the access opening 40 is located in the region of the minimum width B, as shown in FIG. 9. In the direction of the transition radius 45, the width of the clamp 25 increases, so the cross-section increases. The maximum cross-section of the clamp bending portion 28 is located in the region of the transition radius 45. In the illustrated embodiment, its width is 1.64 mm, and the maximum cross-section is 14% larger than the minimum cross-section.

[0085] In the region of the parallel arms 43, 44, the outer clamp width is 2.4 mm, which is 67% larger than the 1.44 mm of the minimum width B. However, due to the above-mentioned nominal dimensions B1, B2, the sum of the two arm cross-sections corresponds to the minimum cross-section outside the access opening 40. As a result, the clamp 25 has very good bending behavior and uniform spring characteristics, and the fatigue strength of the clamp 25 is increased.

[0086] The (engaging) wall 6 assigned to the clamp bending portion 28 has a recess 50 at its (labial) end, and this recess 50 faces away from the bottom 11 of the groove 7. Referring to FIG. 5, the clamp bending portion 28 of the clamp 25 in the closed position is located in this recess 50. The depth J of the recess 50 is at least 80% of the thickness D of the clamp 25. When the bracket is open, the second clamp leg 27 fits into the recess 50 (see FIG. 2).

[0087] Bracket 1 is provided with a support surface 51 that supports the access end 42 of the bracket opener 41. The support surface 51 faces the clamp bending portion 28. The support surface 51 is inclined at an angle G = 75° with respect to the first clamp leg 26.

[0088] To move the clamp 25 from its closed position (see FIG. 1) to its open position (see FIG. 2), the bracket opener 41 is inserted into the access opening 40 together with its access end 42 (FIGS. 10 and 12a). When the access end 42 is inserted in the direction of arrow X in FIG. 12a, it is positioned at the center of the region of the clamp bending portion 28 by the support surface 51 and two arms 43 and 44 that run in a V-shape towards each other. The access end 42 rests in the region of the transition radius 45 on the clamp 25 (see FIG. 12a), and the clamp 25 is still in its closed position.

[0089] When the access end 42 is further pushed in the (tongue) direction X, the opening force exerted by the access end 42 is initially distributed substantially evenly between the two clamp legs 26 and 27. The opening movement of the clamp 25 begins, and the access end 42 slides along the support surface 51. The access end 42 approaches the first clamp leg 26 (see FIG. 12b). Then, when the access end 42 is further pushed in the direction of arrow Y in FIG. 12, most of the leg-opening force exerted by the access end 42 acts on the first clamp leg 26 (FIG. 12c).

[0090] This is particularly advantageous when a plaque is deposited in the slit 18 and the movement of the first clamp leg 26 is sluggish. The protrusion 31 is received in the recess 30 and does not prevent movement. The displacement movement in the (occlusion) direction Y ends when the stopper 33 hits the protrusion 31. At this time, the clamp 25 is in the open position as also shown in FIG. 11. In this open position, the second clamp leg 27 has a stationary position on the occlusion wall 6, and access to the groove 7 from the lip direction is possible at this stationary position.

[0091] The first exemplary embodiment of bracket 1 in FIGS. 1 to 11 is an angular bracket where slit 18 is perpendicular to groove 7. Therefore, clamp 25 runs along a straight line as shown in FIG. 9.

Example

[0092] The second exemplary embodiment shown in FIGS. 13 to 16 is bracket 1 with an angle of 6°. The angle K between groove 7 and the longitudinal direction 29 of slit 18 or the first clamp leg 26 is thus 84°. As a result, the angles C, C’, C’’, C’’’ of the two V-shaped arms 43, 44 with respect to the longitudinal direction of clamp 25 are different. The constant widths B1 and B2 of arms 43 and 44 result in V = C + C’ and V = C’’ + C’’’ respectively. Furthermore, since the design and function of the second exemplary embodiment are the same as those of the first exemplary embodiment, reference is made to avoid repetition.

Explanation of Reference Numerals

[0093] 1…Bracket 2…Fixed Side 3…Projection 4…Base 5…Gingival Wall 6…Occlusal Wall 7…Groove 8…Gingival Ligation Wing 9…Occlusal Ligation Wing 11…Bottom of Groove 7 12…Rib of Wall 6 14…Inclined Plane of Bottom 11 15…Inclined Plane on Wall 5 18…Slit 19…Lingual Side 19a…Guide Surface 19b…Guide Surface 20…Labial Side 21…Side Wall 24…Notch 25…Clamp 26…First Clamp Leg 26a…Beginning of First Clamp Leg 26 27…Second Clamp Leg 27a…The starting part of the second clamp leg 27 27b…Extension part 28…Clamp bending part 29…Longitudinal direction 30…Recess 31…Projection 33…Stopper 35…Channel 40…Access opening (tool) 41…Bracket opener 42…Access end 43…Proximal arm 44…Distal arm 45…Transition radius 46…Center 50…Recess 51…Support surface A…Distance B…Width B1…Width B2…Width C…Angle D…Thickness E…Bending angle F…Bending angle G…Angle H1…The first height H2…The second height J…Depth K…Angle V…Angle X…Direction Y…Direction

Claims

1. A self-ligating bracket (1) for dental orthodontics, comprising: a base (4); an occlusal wall (6) extending from the base (4); a gingival wall (5) extending from the base (4); a groove (7) separating the occlusal wall (6) and the gingival wall (5) and continuously extending from the mesial side to the distal side; a fixing side surface (2) facing the opposite side from the groove (7) for adhering the bracket (1) to the lingual surface or the vestibular surface of a tooth; a slit (18) extending in a direction from the gingiva toward occlusion; an elastic clamp (25) composed of a first clamp leg (26) and a second clamp leg (27), which are connected to each other by a clamp bending portion (28) arranged on the occlusal side or the gingival side; and the first clamp leg (26) is inserted into the slit (18) and is movable in the gingival-occlusal direction between the closed position and the open position of the clamp (25), and the clamp (25) has an access opening (40) for engaging a bracket opener (41) in the region of the clamp bending portion (28), the access opening (40) is laterally delimited by a mesial arm (43) and a distal arm (44) running in a V-shape toward each other along the longitudinal direction (29) of the first clamp leg (26) or when viewing the clamp (25) wound back in a plane from above, the distance (A) measured from the mesial to the distal between the mesial arm (43) and the distal arm (44) is at least as large as the respective arm widths (B1; B2) of the two arms (43, 44) measured from the mesial to the distal, the cross-section of the clamp (25) in the region of the clamp bending portion (28) outside the access opening (40) has a minimum value called the minimum cross-section, each of the mesial arm (43) and the distal arm (44) has an arm cross-section in the region of the access opening (40), and the sum of the two arm cross-sections at a point of the clamp bending portion (28) is smaller than the minimum cross-section by 10% or less. A self-ligating bracket characterized by this.

2. In claim 1, The self-ligating bracket is characterized in that each of the arm widths (B1; B2) of the centripetal arm (43) and the centrifugal arm (44) is half the width of the minimum width (B) of the clamp bending portion (28) in the region outside the access opening (40).

3. In claim 1, the cross-section of the clamp (25) in the region of the clamp bending portion (28) has a maximum value called the maximum cross-section, the self-ligating bracket is characterized in that the maximum cross-section is enlarged by 20% or less of the minimum cross-section.

4. In claim 1, the self-ligating bracket is characterized in that the clamp bending portion (28) having a cross-section 10% or more larger than the minimum cross-section has a bending angle exceeding 20% of the total bending angle (F) of the clamp bending portion (28) and not exceeding 30°.

5. In claim 1, the self-ligating bracket is characterized in that the distance (A) between the centripetal arm (43) and the centrifugal arm (44) is at least 0.7 mm.

6. In claim 1, the self-ligating bracket is characterized in that the angle (V) between the centripetal arm (43) and the centrifugal arm (44) is in the range of 40° to 75°.

7. In claim 1, the self-ligating bracket is characterized in that one of the two arms (43; 44) travels at an angle (C; C'; C''; C''') in the range of 20° to 45° with respect to the longitudinal direction of the clamp (25) in a top view in which the clamp (25) is wound back to a plane.

8. In claim 1, the access opening (40) is oval and extends over at least 50% of the entire clamp bending portion (28), the self-ligating bracket being characterized thereby.

9. In claim 1, the access opening (40) is oval and extends over a bending angle (E) of the clamp bending portion (28) of at least 100°, the self-ligating bracket being characterized thereby.

10. In claim 1, the section of the clamp bending portion (28) where the two arms (43, 44) run parallel to each other is adjacent to the section of the clamp bending portion (28) where the two arms (43, 44) run in a V-shape towards each other, the self-ligating bracket being characterized thereby.

11. In claim 1, the clamp bending portion (28) has a center (46) located at a first height (H1) above the first clamp leg (26) as viewed in a longitudinal section passing through the first clamp leg (26), the end of the access opening (40) facing the first clamp leg (26) is located at a second height (H2) above the first clamp leg (26), the second height (H2) is within a range delimited by the first height reduced by 20% (0.8 * H1) and the first height increased by 20% (1.2 * H1), characterized in that it is a self-ligating bracket.

12. In claim 1, a support surface (51) for a bracket opener (41) is provided, which faces the clamp bending portion (28), is oblique to the first clamp leg (26), and runs at an angle (G) of 60° to 85°, characterized in that it is a self-ligating bracket.

13. In claim 1, the occlusal wall (6) or the gingival wall (5) is assigned to the clamp bending portion (28), where, as viewed along the longitudinal direction (29) of the first clamp leg (26), the wall (6) assigned to the clamp bending portion (28) has a recess (50) at an end facing away from the bottom of the groove (7), and the second clamp leg (27) and / or the clamp bending portion (28) of the clamp (25) in the closed position are seated in the recess (50), characterized in that it is a self-ligating bracket.

14. In claim 13, the depth (J) of the recess (50) is at least 80% of the thickness (D) of the clamp (25), characterized in that it is a self-ligating bracket.

15. A series of the orthodontic self-ligating brackets (1) comprising a number of brackets (1) according to any one of claims 1 to 14, wherein the minimum cross-section of the clamp (25) in the region of the clamp bending portion (28) of one bracket (1) in the series differs by 10% or less from the respective minimum cross-sections of the other brackets (1) in the series, characterized in that it is a series of orthodontic self-ligating brackets (1).

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