Elliptical hollow steel needle appliance and correction system

Abstract

The utility model discloses an elliptical hollow steel needle appliance and an orthodontic system.The elliptical hollow steel needle appliance comprises a bracket body, a cover plate, an elastic part and a working part, the cover plate is slidably assembled on the bracket body, and a first groove body, a second groove body and a third groove body are formed in the cover plate; at least the section of the working part is non-circular and has a long axis direction and a short axis direction which are opposite to each other, the long axis direction of the working part points to the extension direction of the arch wire groove, and the short axis direction of the working part points to the first direction; when the cover plate is located in the closed arch wire groove, the working part is located in the first groove body, the restraining side wall of the first groove body is attached to and wraps the peripheral face of the working part in the long axis direction, and the receding side wall of the first groove body is away from the peripheral face of the working part in the short axis direction to form a receding area. Through optimization of the locking mechanism, especially collaborative optimization of the positioning groove and the elastic piece, synchronous improvement of the locking effect and the operation experience of the cover piece is achieved, the user experience is improved, and positive significance is achieved on improvement of the correction effect.

Description

Technical Field

[0001] The present application relates to the field of dental correction, and in particular to an elliptical hollow steel needle correction appliance and a correction system. Background Art

[0002] Brackets are a type of equipment used in orthodontic correction, and are mainly used by orthodontists to perform clinical orthodontic treatment of dentition. Currently in the orthodontic industry, self-ligating brackets have become a market trend, with complete parameters, and are beginning to trend towards mid- to high-end products. Self-ligating brackets are used in conjunction with archwires, which apply force to control the direction of the teeth to achieve the purpose of correcting teeth.

[0003] Self-ligating brackets usually include a mesh base for bonding, a bracket body located on the mesh base, a cover sheet movably mounted on the bracket body, and a locking structure provided between the cover sheet and the bracket body support. Self-ligating brackets rely on a locking structure to change the cover sheet to maintain a specific position, especially the closed position where the cover sheet closes the archwire slot. However, during actual use, the archwire located in the archwire slot will exert forces in various dimensions on the bracket body and the cover sheet. Combined with the impact of foreign matter on the self-ligating bracket during eating, the cover sheet is prone to appearing and falling under the impact of foreign matter, self-locking failure, and plastic deformation of the locking mechanism. The above risks range from product failure to damage the patient's oral cavity.

[0004] The market is constantly iterating on the optimization of self-ligating bracket structures, but there is always a need to balance the locking strength and ease of operation, which are somewhat contradictory technical requirements, and there is room for improvement. Utility Model Content

[0005] In order to solve the above technical problems, the present application discloses an elliptical hollow steel needle appliance, comprising:

[0006] a bracket body, the bracket body defining a slideway;

[0007] A cover sheet is slidably assembled on the slideway, the slideway only allows the cover sheet to move in the first direction, and the cover sheet is provided with a positioning groove, the positioning groove comprising a first groove body, a second groove body and a third groove body which are sequentially connected in the first direction;

[0008] The elastic member comprises a fitting portion inserted into the bracket body and a working portion extending into the positioning groove, wherein at least the cross section of the working portion is non-circular and has a relative long axis direction and short axis direction, the long axis direction of the working portion points to the extension direction of the archwire slot, and the short axis direction of the working portion points to the first direction;

[0009] When the cover plate is in the closed position closing the arch wire groove, the working part is located in the first groove body. The two opposite side walls of the first groove body are constraint side walls. The two constraint side walls are attached and wrap the outer peripheral surface of the working part in the long axis direction. The side wall connecting the two constraint side walls of the first groove body is an avoidance side wall, and the avoidance side wall forms an avoidance area away from the outer peripheral surface of the working part in the short axis direction.

[0010] When the cover plate is in the open position opening the arch wire groove, the working part is located in the third groove body. The side wall of the third groove body squeezes the working part in the long axis direction to drive it to deform and fits the outer peripheral surface of the working part in the short axis direction.

[0011] When the cover plate moves between the closed position and the open position, the side wall at the connection position between the groove bodies of the positioning groove squeezes the working part in the long axis direction to drive it to deform and enter the second groove body. The degree of deformation of the working part in the second groove body is greater than the degree of deformation of the working part in the third groove body.

[0012] The following also provides several optional ways, but it is not an additional limitation to the above overall solution, but only a further supplement or preference. Without technical or logical contradictions, each optional way can be combined with the above overall solution alone, or multiple optional ways can be combined with each other.

[0013] In one embodiment, the second groove body is a straight groove open at both ends and communicates with the first groove body and the third groove body at both ends respectively. The side walls of each groove body are smoothly arranged and the connection positions between the groove bodies are smoothly transitioned.

[0014] In one embodiment, the cross-sectional shapes of the first groove body and the third groove body are C-shaped and the openings are used to cooperate with the working part. The bottom of the C-shape of the first groove body forms an avoidance area away from the outer peripheral surface of the working part.

[0015] In one embodiment, the inside of the working part is hollow and the outer edge of the cross-sectional shape is an ellipse. The minimum distance between the two constraint side walls is less than the major axis dimension of the ellipse. In the first direction, each constraint side wall extends at least to both sides of the major axis of the ellipse.

[0016] In one embodiment, the bracket body is provided with a positioning hole facing the cover plate. At different positions of the cover plate, the positioning hole respectively aligns with different groove bodies of the positioning groove, and at least the assembly part of the elastic part is inserted into the positioning hole.

[0017] In one embodiment, the positioning hole penetrates through the bracket body. An enlarged diameter section is provided at one end of the positioning hole close to the cover plate. The elastic member further includes an adaptation portion located between the assembly portion and the working portion. During the deformation process of the working portion, the adaptation portion deforms in a convergent manner and is released through the enlarged diameter section.

[0018] In one embodiment, the elastic member is of an integral structure and is in an overall cylindrical structure. The assembly portion, the adaptation portion, and the working portion are respectively provided by the respective axial sections of the cylindrical structure. The outer edge of the cross-sectional shape of the cylindrical structure is an ellipse, and the side walls of the cylindrical structure are uniformly arranged. The ratio range of the dimension D1 in the major axis direction to the dimension D2 in the minor axis direction of the ellipse is from 1.1 to 1.45.

[0019] In one embodiment, a dovetail slider is provided on one of the bracket body and the cover plate, and a dovetail groove is provided on the other. The dovetail slider or the dovetail groove on the bracket body is used to define the slideway, and the positioning hole penetrates through the dovetail slider or the dovetail groove in the height direction.

[0020] In one embodiment, in the axial direction of the elastic member, the length L1 of the working portion accounts for at least 10% of the total length L2 of the elastic member; the ratio range of the length L1 of the working portion to the dimension D3 in the minor axis direction of the working portion is from 0.4 to 1; the depth of the positioning groove is adapted to the length of the working portion.

[0021] The present application also discloses an orthodontic system, including a plurality of orthodontic appliances and arch wires. At least one orthodontic appliance is the elliptical hollow steel needle orthodontic appliance in the above technical solution.

[0022] Through the optimization of the locking mechanism, especially the coordinated optimization of the positioning groove and the elastic member, the technical solution disclosed in the present application realizes the synchronous improvement of the locking effect and the operation experience of the cover plate, improves the user experience, and has positive significance for improving the orthodontic effect.

[0023] The specific beneficial technical effects will be further explained in combination with specific structures or steps in the specific implementation manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of an orthodontic appliance in one embodiment;

[0025] Figure 2 It is Figure 1 a schematic diagram of the internal mating structure of the orthodontic appliance shown in

[0026] Figure 3 It is Figure 1 an exploded view of the orthodontic appliance shown in

[0027] Figure 4Schematic structural diagram of the cross-section where the positioning groove is located in an embodiment (the elastic member is omitted in the figure);

[0028] Figure 5 is Figure 5 Schematic diagram of the cooperation between the positioning groove and the elastic member shown in;

[0029] Figure 6 Orthodontic appliance schematic diagram in another embodiment.

[0030] The reference signs in the figure are explained as follows:

[0031] 1. Bracket body; 11. Slideway; 111. Dovetail slider; 12. Arch wire groove; 13. Positioning hole; 131. Diameter-expanded section;

[0032] 2. Cover plate; 21. Positioning groove; 211. First groove body; 2111. Constraint side wall; 2112. Avoidance side wall; 2113. Avoidance area; 212. Second groove body; 213. Third groove body;

[0033] 3. Elastic member; 31. Assembly part; 32. Adaptation part; 33. Working part;

[0034] 4. Traction hook. Specific implementation manners

[0035] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0036] It should be noted that when a component is referred to as being "connected" to another component, it can be directly connected to the other component or there may also be an intermediate component. When a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may be an intermediate component at the same time.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the specification of this application herein are only for the purpose of describing specific embodiments, and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0038] Referring to Att Figure 1 to Att Figure 5 shown, the present application discloses an elliptical hollow steel needle orthodontic appliance, including:

[0039] Bracket body 1, the bracket body 1 defines a slideway 11;

[0040] Cover plate 2, slidably assembled on the slideway 11, the slideway 11 only allows the cover plate 2 to move in the first direction (for example, the direction of the slideway 11 shown in the attached drawing), a positioning groove 21 is provided on the cover plate 2, and the positioning groove 21 includes a first groove body 211, a second groove body 212 and a third groove body 213 that are sequentially communicated in the first direction;

[0041] Elastic member 3, including an assembly portion 31 inserted into the bracket body 1 and a working portion 33 extending into the positioning groove 21, at least the cross-section of the working portion 33 is non-circular and has opposite major axis directions and minor axis directions, the major axis direction of the working portion 33 points to the extension direction of the arch wire groove 12, and the minor axis direction of the working portion 33 points to the first direction.

[0042] The non-circular working portion 33 can better adjust its own shape to synchronously improve the use effect under different working conditions. For example, in the closed position of the cover plate 2, the non-circular working portion 33 has a better locking effect to avoid the locking failure of the cover plate 2; for another example, during the process of the cover plate 2 switching positions, the setting with optimized major axis and minor axis direction dimensions can concentrate stress to drive the deformation of the working portion 33 and reduce the resistance during the movement of the cover plate 2.

[0043] Specifically, when the cover plate 2 is in the closed position closing the arch wire groove 12 (refer to the attached Figure 4 drawing), the working portion 33 is located in the first groove body 211, the opposite side walls of the first groove body 211 are constraint side walls 2111, the two constraint side walls 2111 are attached and wrap the outer peripheral surface of the working portion 33 in the major axis direction, the side wall of the first groove body 211 connecting the two constraint side walls 2111 is an avoidance side wall 2112, and the avoidance side wall 2112 forms an avoidance area 2113 away from the outer peripheral surface of the working portion 33 in the minor axis direction;

[0044] When the cover plate 2 is in the open position opening the arch wire groove 12, the working portion 33 is located in the third groove body 213, and the side wall of the third groove body 213 squeezes the working portion 33 in the major axis direction to drive its deformation and fits the outer peripheral surface of the working portion 33 in the minor axis direction;

[0045] When the cover plate 2 moves between the closed position and the open position, the side walls at the connection positions between the groove bodies of the positioning groove 21 squeeze the working portion 33 in the major axis direction to drive its deformation and enter the second groove body 212, and the deformation degree of the working portion 33 in the second groove body 212 is greater than the deformation degree of the working portion 33 in the third groove body 213.

[0046] Overall, through the optimization of the locking mechanism, especially the coordinated optimization of the positioning groove 21 and the elastic member 3, the present application achieves the synchronous improvement of the locking effect and the operating experience of the cover sheet 2, improves the user experience, and has a positive significance for improving the orthodontic effect.

[0047] It can be understood that the movement and positioning of the cover sheet 2 mainly depend on the cooperative setting of the positioning groove 21 and the elastic member 3, which will be elaborated separately below.

[0048] In terms of the specific setting details of the positioning groove 21, referring to the attached Figure 4 and the attached Figure 5 In the embodiment shown, the second groove body 212 is a straight groove with both ends open and is connected to the first groove body 211 and the third groove body 213 at both ends respectively. The working part 33 can move in each groove body. In order to reduce the running resistance, the side walls of each groove body are smoothly arranged and the connection positions between the groove bodies are smoothly transitioned. In terms of the specific shape, the cross-sectional shapes of the first groove body 211 and the third groove body 213 are C-shaped and the openings are used to cooperate with the working part 33. The bottom of the C-shape of the first groove body 211 forms an avoidance area 2113 away from the outer peripheral surface of the working part 33. The avoidance area 2113 can release the deformation space of the working part 33, thereby improving the driving experience in a specific driving direction of the cover sheet 2.

[0049] In terms of the specific setting details of the elastic member 3, referring to the attached Figures 2 to 3 and the attached Figure 5 In the embodiment shown, the working part 33 is hollow inside and the outer edge of the cross-sectional shape is an ellipse. The hollow setting of the working part 33 can be used to adjust the elastic performance of the elastic member 3, so as to adapt to different design requirements. The minimum distance between the two constraint side walls 2111 is less than the major axis dimension of the ellipse. In the first direction, each constraint side wall 2111 extends at least to both sides of the major axis of the ellipse. For example, in the attached Figure 5 In, the constraint side walls 2111 extend at least to both sides of the major axis of the ellipse in the left-right direction in the figure. Each constraint side wall 2111 can avoid the problem of reduced constraint moment caused by the hollow setting of the elastic member 3 by enclosing the outer surface near the major axis, thereby avoiding the accidental unlocking of the cover sheet 2. In the overall shape, the elastic member 3 is an integral structure and is a cylindrical structure as a whole. The assembly part 31, the adaptation part 32 and the working part 33 are respectively provided by the axial sections of the cylindrical structure. The outer edge of the cross-sectional shape of the cylindrical structure is an ellipse and the side walls of the cylindrical structure are evenly arranged. The ratio range of the major axis direction dimension D1 to the minor axis direction dimension D2 of the ellipse is 1.1 to 1.45. The side wall thickness H1 of the cylindrical structure is 0.05 mm to 0.15 mm. In the figure, the ratio range of the major axis direction dimension D1 to the minor axis direction dimension D2 of the ellipse is 1.2 to 1.4. The side wall thickness H1 of the cylindrical structure is 0.06 mm to 0.1 mm. In terms of the specific material, the elastic member is a thin-walled structure made of an elastic metal such as nickel-titanium or stainless steel.

[0050] In the mating relationship between the elastic member 3 and the positioning groove 21, as can be seen from the attached Figure 5 figure, when the working portion 33 is located in the first groove body 211, it fits against the constraint side wall 2111, that is, the dimensional tolerances of the two belong to a transition fit. In the free state, the working portion 33 does not deform within the first groove body 211. When the working portion 33 is located in the third groove body 213, it is squeezed against the side wall of the third groove body 213, that is, the dimensional tolerances of the two belong to an interference fit. In the free state, the working portion 33 deforms within the third groove body 213. The working portion 33 located in the third groove body 213 shown by the dashed line in the attached Figure 5 figure is in an un-squeezed state, that is, the size of the working portion 33 located in the first groove body 211 is used to clearly indicate the dimensional difference between the first groove body 211 and the third groove body 213. The advantage of this setting is that it can generate a prestress on the working portion 33 located in the third groove body 213 to improve the working process of the working portion 33 leaving the third groove body 213. Corresponding to the relative position of the cover plate 2, the cover plate 2 preferably can be better held in the closed position and more easily enter the closed position from the open position. Based on this, the connection position between the third groove body 213 and the second groove body 212 is smoother than the connection position between the first groove body 211 and the second groove body 212.

[0051] In terms of the installation method of the elastic member 3, it can be directly arranged on the bracket body 1. For example, in the Figure 3 embodiment shown in the attached figure, the bracket body 1 is provided with a positioning hole 13 facing the cover plate 2. At different positions of the cover plate 2, the positioning hole 13 is respectively aligned with different groove bodies of the positioning groove 21, and at least the assembly portion 31 of the elastic member 3 is inserted into the positioning hole 13. Further, as shown in the attached Figure 2 figure, the positioning hole 13 penetrates through the bracket body 1. The end of the positioning hole 13 away from the cover plate 2 can be closed by various methods such as welding and bonding, for example, by a mesh bottom (not shown in the figure). The above setting facilitates the installation and debugging of the elastic member 3. In the attached Figure 2 figure, Figure 3 figure, Figure 4 and the attached figure, the end of the positioning hole 13 close to the cover plate 2 is provided with an enlarged diameter section 131. The elastic member 3 further includes an adaptation portion 32 located between the assembly portion 31 and the working portion 33. During the deformation process of the working portion 33, the adaptation portion 32 deforms in a similar manner and is released through the enlarged diameter section 131. The adaptation portion 32 can further improve the compliance of the elastic member 3.

[0052] In the matching relationship between the positioning hole 13 and the elastic member 3, refer to the attached Figure 2 figure and the attached Figure 5As shown, in the axial direction of the elastic member 3, the length L1 of the working portion 33 accounts for at least 10% of the total length L2 of the elastic member 3; the ratio range between the length L1 of the working portion 33 and the dimension D3 in the short-axis direction of the working portion 33 is from 0.4 to 1. The dimension D2 in the short-axis direction and the dimension D3 in the short-axis direction may be equal, or may be differently set in different embodiments. Further, the depth of the positioning groove 21 is adapted to the length of the working portion 33. The adaptation may be set such that the top end of the working portion 33 contacts the upper top surface of the positioning groove 21, or may be set such that there is a clearance between the top end of the working portion 33 and the upper top surface of the positioning groove 21, and the clearance distance is less than or equal to the side wall thickness H1 of the cylindrical structure.

[0053] In terms of the implementation manner of the slideway 11, the publicly disclosed solutions in the prior art may be adopted, or as shown in the figure, a dovetail slider 111 is provided on one of the bracket body 1 and the cover sheet 2, and a dovetail groove (not shown in the figure) is provided on the other. The dovetail slider 111 or the dovetail groove on the bracket body 1 is used to define the slideway 11 and is provided with a positioning hole 13 penetrating through the dovetail slider 111 or the dovetail groove in the height direction. In the figure, the bracket body 1 is provided with a dovetail slider 111, and the cover sheet 2 is provided with a dovetail groove. The dovetail slider 111 and the dovetail groove are engaged with each other in the height direction to enable the cover sheet 2 to move only in the first direction. The dovetail slider 111 and the dovetail groove can also cooperate with the positioning hole 13. For example, the dovetail slider 111 or the dovetail groove on the bracket body 1 is used to define the slideway 11 and is provided with a positioning hole 13 penetrating through the dovetail slider 111 or the dovetail groove in the height direction.

[0054] In addition, the orthodontic appliance disclosed in the present application can be further optimized for different tooth positions and orthodontic treatment plans, for example, Figure 6 The orthodontic appliance in Figure 1 to Figure 5 Compared with the embodiments shown, a traction hook 4 is further provided on the bracket body 1, and the traction hook 4 is arranged away from the arch wire groove 12 on the surface of the bracket body 1. Correspondingly, the extending direction of the arch wire groove 12 and the connection relationship of the bracket body 1 relative to the mesh bottom can be adjusted accordingly to meet the needs of orthodontic data expression.

[0055] According to the above description, it is not difficult to understand that the present application also discloses an orthodontic system, including a plurality of orthodontic appliances and an arch wire (not shown in the figure), and at least one orthodontic appliance is the elliptical hollow steel needle orthodontic appliance in the above technical solution.

[0056] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification. When the technical features in different embodiments are shown in the same drawing, it can be regarded that the drawing also discloses the combination examples of the respective embodiments involved.

[0057] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several variations and improvements can still be made, and these all fall within the protection scope of the present application.

Claims

1. Elliptical hollow steel needle appliance, characterized in that: include: a bracket body, the bracket body defining a slideway; A cover sheet is slidably assembled on the slideway, the slideway only allows the cover sheet to move in the first direction, and the cover sheet is provided with a positioning groove, the positioning groove comprising a first groove body, a second groove body and a third groove body which are sequentially connected in the first direction; The elastic member comprises a fitting portion inserted into the bracket body and a working portion extending into the positioning groove, wherein at least the cross section of the working portion is non-circular and has a relative long axis direction and short axis direction, the long axis direction of the working portion points to the extension direction of the archwire slot, and the short axis direction of the working portion points to the first direction; When the cover is in a closed position that closes the archwire slot, the working part is located in the first slot body, and the two opposite side walls of the first slot body are constraining side walls, which are attached to and cover the outer peripheral surface of the working part in the direction of the major axis, and the side wall of the first slot body connecting the two constraining side walls is an avoidance side wall, which is away from the outer peripheral surface of the working part in the direction of the minor axis to form an avoidance area; When the cover is located at the opening position of the archwire slot, the working part is located in the third slot body, and the side wall of the third slot body presses the working part in the long axis direction to drive it to deform and fit the outer peripheral surface of the working part in the short axis direction; When the cover moves between the closed position and the open position, the side walls of the connecting positions between the groove bodies of the positioning groove squeeze the working part in the long axis direction to drive it to deform and enter the second groove body, and the deformation degree of the working part in the second groove body is greater than the deformation degree of the working part in the third groove body.

2. The elliptical hollow steel needle appliance according to claim 1, characterized in that: The second slot body is a straight slot with two open ends, and the two ends are respectively connected to the first slot body and the third slot body. The side wall of each slot body is smoothly arranged and the connection position between each slot body is smoothly transitioned.

3. The elliptical hollow steel needle appliance according to claim 1, characterized in that: The cross-sectional shape of the first groove body and the third groove body is C-shaped and the openings are used to cooperate with the working part. The C-shaped bottom of the first groove body is away from the outer peripheral surface of the working part to form an escape zone.

4. The elliptical hollow steel needle appliance according to claim 1, characterized in that: The working portion is hollow inside and has an outer edge of an ellipse in cross-section. The minimum spacing between the two constraining side walls is smaller than the major axis size of the ellipse. In the first direction, each constraining side wall extends to at least both sides of the major axis of the ellipse.

5. The elliptical hollow steel needle appliance according to claim 1, characterized in that: The bracket body is provided with a positioning hole arranged toward the cover sheet. When the cover sheet is in different positions, the positioning hole is respectively aligned with different groove bodies of the positioning groove, and at least the assembly portion of the elastic member is inserted into the positioning hole.

6. The elliptical hollow steel needle appliance according to claim 5, characterized in that: The positioning hole passes through the bracket body, and an expansion section is provided at one end of the positioning hole close to the cover plate. The elastic member also includes an adapter portion located between the assembly portion and the working portion. During the deformation of the working portion, the adapter portion deforms convergently and is released through the expansion section.

7. The elliptical hollow steel needle appliance according to claim 6, characterized in that: The elastic part is an integral structure and is a cylindrical structure as a whole. The assembly part, the adapter part and the working part are respectively provided by axial sections of the cylindrical structure. The outer edge of the cross-sectional shape of the cylindrical structure is an ellipse and the side walls of the cylindrical structure are evenly arranged. The ratio between the major axis dimension D1 and the minor axis dimension D2 of the ellipse ranges from 1.1 to 1.

45.

8. The elliptical hollow steel needle appliance according to claim 5, characterized in that: One of the bracket body and the cover plate is provided with a dovetail slider, and the other is provided with a dovetail groove. The dovetail slider or dovetail groove on the bracket body is used to define the slideway and is provided with the positioning hole penetrating the dovetail slider or the dovetail groove in the height direction.

9. The elliptical hollow steel needle appliance according to claim 1, characterized in that: In the axial direction of the elastic part, the length L1 of the working part accounts for at least 10% of the total length L2 of the elastic part; the ratio between the length L1 of the working part and the short axis dimension D3 of the working part ranges from 0.4 to 1; the depth of the positioning groove and the length of the working part are adapted to each other.

10. A correction system, characterized in that: It comprises a plurality of orthodontic appliances and dental arch wires, at least one of which is an elliptical hollow steel needle orthodontic appliance according to any one of claims 1 to 9.

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