Long-arm hook accessory and manufacturing method thereof

Abstract

The long-arm hook accessory is used for being bonded to the tooth surface to suspend a traction piece and comprises a long-arm hook and a main body part, the long-arm hook extends to form a rod part, a suspension part used for suspending the traction piece is formed at the first end of the rod part, and the main body part is arranged at the second end of the rod part. One section, close to a second end opposite to the first end, of the long arm hook is buried in the main body part, the main body part comprises a first part and a second part formed by extending from the first part, and the width of the first part of the main body part is larger than that of the second part of the main body part; the hanging part of the long-arm hook extends out of the second part of the main body part, and the height of the second part of the main body part is greater than the diameter of the rod part of the long-arm hook.

Description

Technical Field

[0001] The present application generally relates to a long arm hook attachment and a method of making the same. Background Art

[0002] Shell-shaped dental appliances based on polymer materials are becoming more and more popular due to their advantages of beauty, convenience and ease of cleaning. Shell-shaped dental appliances are usually an integrated shell that forms a cavity to accommodate multiple teeth, and the geometry of the cavity is basically consistent with the teeth in the corresponding layout.

[0003] Orthodontic treatment using shell-like dental appliances generally requires dozens of successive shell-like dental appliances, which are worn successively to gradually reposition the patient's teeth from an initial tooth configuration to a target tooth configuration.

[0004] When using a shell-shaped dental appliance to translate teeth, for example, to close the gap after tooth extraction, the teeth are likely to tilt, mainly because it is difficult to achieve the ideal root movement control effect by relying solely on a shell-shaped dental appliance. Therefore, long-arm hooks are introduced in clinical practice for traction to provide a good axial tilt torque and effectively achieve overall translation of the teeth.

[0005] In the existing solutions, the long arm hook is not ideal in terms of bonding experience, mechanical control, and interference with gums. Therefore, it is necessary to provide a new shell-shaped dental appliance and a kit of a long arm hook attachment. Summary of the invention

[0006] One aspect of the present application provides a long arm hook attachment for bonding to the tooth surface to hang a traction member, comprising a long arm hook and a main body, wherein the long arm hook extends to form a rod portion, the first end of the rod portion forms a hanging portion for hanging the traction member, a section of the second end of the long arm hook opposite to the first end is buried in the main body, the main body portion comprises a first part and a second part extending from the first part, the width of the first part of the main body portion is greater than the second part of the main body portion, the hanging portion of the long arm hook extends out of the second part of the main body portion, and the height of the second part of the main body portion is greater than the diameter of the rod portion of the long arm hook.

[0007] In some embodiments, the long arm hook is an integral component made of metal material, and the main body is an integral component made of polymer material.

[0008] In some embodiments, the long arm hook forms a head at the second end, the lateral dimension of the head is larger than that of the rod, and the head is buried in the second part of the main body.

[0009] In some embodiments, the stem portion is located at a section of the second portion of the body portion away from the tooth surface.

[0010] In some embodiments, at least a section of the second portion of the main body is narrowed inward near the tooth surface to form an inwardly-retracted portion, and the minimum width of at least one point of the inwardly-retracted portion in the extension direction of the second portion of the main body is smaller than the diameter of the rod of the long arm hook. At the point where the minimum width of the inwardly-retracted portion is smaller than the diameter of the rod of the long arm hook, the rod of the long arm hook is located on the side of the inwardly-retracted portion away from the tooth surface.

[0011] In some embodiments, the second portion of the main body as a whole narrows inwardly near the tooth surface to form an inward portion, and the minimum width of the inward portion gradually decreases from one end of the second portion close to the first portion to the other end.

[0012] In some embodiments, a height of the second portion gradually increases from one end of the second portion close to the first portion to the other end.

[0013] In some embodiments, the first portion forms a first inclined surface at one end close to the occlusal surface to facilitate wearing of the shell-shaped dental appliance.

[0014] In some embodiments, second inclined surfaces are formed on both sides of the second portion of the first portion at an end away from the occlusal surface to facilitate removal of the shell-shaped dental appliance.

[0015] A shell-shaped dental appliance is an integrated shell, forming a first cavity for accommodating multiple teeth and at least one second cavity for accommodating the main body of the long arm hook attachment, wherein the geometry of the second cavity is consistent with the main body of the long arm hook attachment, and the second cavity extends to the edge of the shell-shaped dental appliance.

[0016] In some embodiments, the geometry of the first cavity conforms to the tooth in a first tooth configuration.

[0017] A method for manufacturing a long-arm hook accessory comprises: obtaining a mold that accommodates the long-arm hook and is filled with the material of the main body, the mold comprising a cavity whose geometric shape matches the main body of the long-arm hook accessory; and solidifying the material of the main body filled in the mold to obtain the long-arm hook accessory.

[0018] In some embodiments, the method for making the long arm hook attachment further includes: before solidifying the material of the main body in the mold, adjusting the angle of the rod of the long arm hook according to the protrusion of the patient's gums.

[0019] In some embodiments, the material of the main body is a photocurable resin, and the curing is performed by light irradiation.

[0020] A mounting template for the long-arm hook accessory is an integrated shell, forming a first cavity for accommodating a plurality of teeth and at least one second cavity for accommodating a main body of the long-arm hook accessory, wherein the geometry of the first cavity matches the teeth under the patient's current tooth layout, and the geometry of the second cavity matches the main body of the long-arm hook accessory.

[0021] A shell-shaped dental appliance is an integrated shell, forming a first cavity for accommodating multiple teeth and at least one second cavity for accommodating a main body of a long-arm hook attachment, wherein the second cavity includes a first part close to the crown of the tooth and a second part close to the gum, the width of the first part is greater than that of the second part, and the second part of the second cavity extends to the edge of the shell-shaped dental appliance.

[0022] In some embodiments, the long arm hook accessory includes a long arm hook and a main body, the long arm hook extends to form a rod portion, the first end of the rod portion forms a hanging portion for hanging a traction member, a section of the second end of the long arm hook opposite to the first end is buried in the main body, the main body includes a first part and a second part extending from the first part, the width of the first part of the main body is greater than the second part of the main body, the hanging portion of the long arm hook extends out of the second part of the main body, and the height of the second part of the main body is greater than the diameter of the rod portion of the long arm hook.

[0023] In some embodiments, the height of the second portion of the main body gradually increases from one end close to the first portion of the main body to the other end.

[0024] In some embodiments, the first portion of the main body forms a first inclined surface at one end close to the occlusal surface to facilitate wearing of the shell-shaped dental appliance.

[0025] In some embodiments, the first portion of the main body forms second inclined surfaces on both sides of the second portion at an end away from the occlusal surface to facilitate removal of the shell-shaped dental appliance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and other features of the present application will be further described below in conjunction with the accompanying drawings and detailed descriptions thereof. It should be understood that these drawings only illustrate several exemplary embodiments according to the present application and should not be considered as limiting the scope of protection of the present application. Unless otherwise specified, the drawings are not necessarily to scale and similar reference numerals represent similar components.

[0027] Figure 1 A shell-shaped dental appliance in one embodiment of the present application is schematically shown;

[0028] Figure 2 Schematically shows Figure 1 The second cavity shown;

[0029] Figure 3A The long arm hook attachment in one embodiment of the present application is schematically shown;

[0030] Figure 3B for Figure 3A A cross-sectional view of the long arm hook attachment at AA is shown;

[0031] Figure 4 An example of the application of the long arm hook attachment is schematically shown;

[0032] Figure 5A A front view of a second cavity of a template in one embodiment;

[0033] Figure 5B for Figure 5A A left side view of the second chamber is shown;

[0034] Figure 5C for Figure 5A A cross-sectional view of the second chamber at BB is shown;

[0035] Fig. 6A A front view of the second cavity of the template in another embodiment;

[0036] Figure 6B for Fig. 6A A left side view of the second chamber is shown;

[0037] Figure 6C for Fig. 6A A cross-sectional view of the second chamber at CC is shown;

[0038] Fig.6D for Fig. 6A A cross-sectional view of the second cavity shown at DD; and

[0039] Figure 7 Schematic showing how to make the long arm hook attachment using the template. DETAILED DESCRIPTION

[0040] The following detailed description refers to the drawings that form a part of this specification. The illustrative embodiments mentioned in the specification and the drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present application. Under the enlightenment of the present application, those skilled in the art will understand that many other embodiments can be adopted, and various changes can be made to the described embodiments without departing from the main purpose and scope of protection of the present invention. It should be understood that the various aspects of the present application described and illustrated herein can be arranged, replaced, combined, separated and designed according to many different configurations, and these different configurations are within the scope of protection of the present application.

[0041] In order to overcome the shortcomings of the existing shell-shaped dental appliance and long-arm hook, the present application provides a new shell-shaped dental appliance and long-arm hook accessory kit.

[0042] Please refer to Figure 1 , schematically showing a shell-shaped dental appliance 100 in one embodiment of the present application.

[0043] The shell-shaped dental appliance 100 is an integrated shell, forming a first cavity 101 for accommodating teeth and a second cavity 103 for accommodating a long-arm hook attachment bonded to the teeth.

[0044] Please refer to Figure 2 , schematically showing Figure 1 The second cavity 103 is shown.

[0045] The second cavity 103 includes a first portion 1031 away from the gum and a second portion 1033 close to the gum, wherein the first portion 1031 is larger than the second portion 1033 in the mesiodistal direction.

[0046] Please refer to Figure 3A and Figure 3B ,in, Figure 3A The long arm hook attachment 200 in one embodiment of the present application is schematically shown. Figure 3B It is a cross-sectional view of the long arm hook attachment 200 at AA.

[0047] The long arm hook attachment 200 includes a long arm hook 201 and a main body 203. The long arm hook 201 includes a head 2011 and a rod 2013 extending from the head 2011. The rod 2013 forms a hanging portion 2015 at one end away from the head 2011 for hanging a traction member (e.g., a rubber band, a spring, etc.). The long arm hook 201 is usually made of metal material. The size of the head 2011 is larger than the size of the cross section of the rod 2013. Although, Figure 3A The head 2011 shown is a rectangular parallelepiped, but it can be understood from the enlightenment of the present application that it can also be any other suitable shape, such as a disc, a triangular disc, a sphere, etc. Figure 3A The hanging portion 2015 shown is in the shape of a hook, but in light of the present application, it can be understood that it can be any structure capable of hanging a traction member, for example, a T-shaped structure.

[0048] The main body 203 includes a first portion 2031 and a second portion 2033 that are integrally formed, wherein the width (dimension in the proximal-distal direction) of the first portion 2031 is greater than that of the second portion 2033. The head 2011 and the rod 2013 of the long arm hook 201 are partially buried in the main body 203, and the hanging portion 2015 is located outside the main body 203, wherein the head 2011 is buried in the first portion 2031, and the rod 2013 is buried in the second portion 2033.

[0049] In another embodiment, the long arm hook may not be provided with a head, and the whole is a rod, and a hanging part is formed at the end close to the gum. In this case, a section of the rod away from the gum is buried in the first part of the main body, and a section in the middle of the rod is buried in the second part of the main body.

[0050] In one embodiment, the geometry of the second cavity 103 matches the portion of the long arm hook attachment 200 received in the second cavity 103. The first portion 1031 of the second cavity 103 receives the first portion 2031 of the long arm hook attachment 200, and the second portion 1033 of the second cavity 103 receives the second portion 2033 of the long arm hook attachment 200 in whole or in part.

[0051] Please Figure 3A and Figure 3B The first part 2031 of the main body 203 of the long-arm hook attachment 200 forms a first inclined surface 2035 at one end close to the occlusal surface, which can reduce the obstruction of the long-arm hook attachment 200 bonded to the teeth to the shell-like dental appliance 100 during the wearing process of the shell-like dental appliance 100, thereby facilitating the wearing of the shell-like dental appliance 100. The first part 2031 of the main body 203 of the long-arm hook attachment 200 forms second inclined surfaces 2037 on both sides of the second part 2033 at one end away from the occlusal surface, which can reduce the obstruction of the long-arm hook attachment 200 bonded to the teeth to the shell-like dental appliance 100 during the removal process of the shell-like dental appliance 100, thereby facilitating the removal of the shell-like dental appliance 100.

[0052] The size (i.e., thickness) of the second portion 2033 of the main body 203 of the long arm hook attachment 200 along the buccolingual direction is greater than the diameter of the rod 2013 of the long arm hook 201. On the one hand, since a section of the rod 2013 of the long arm hook 201 near the head 2011 is wrapped by the main body 203, compared with the long arm hook 201 alone, the long arm hook attachment 200 has a higher bending rigidity and can therefore withstand a greater traction force. On the other hand, the second portion 1033 of the second cavity 103 of the shell-shaped dental appliance 100 can effectively interact with the second portion 2033 of the main body 203 of the long arm hook attachment 200, further enhancing the root control movement effect. However, the existing long arm hook cannot effectively interact with the receiving cavity of the shell-shaped dental appliance because the rod is thin and close to the tooth surface.

[0053] Please refer to Figure 4 , schematically illustrating an application example of the long arm hook attachment 200.

[0054] The two long arm hook attachments 200 are respectively bonded to two teeth 110, one of which is a tooth that needs to be moved by controlling the root, and the other is an anchoring tooth. The hooks 2015 of the two long arm hook attachments 200 are hung with rubber bands 210 to generate traction between the two long arm hook attachments 200 to provide a torque to prevent the moving tooth from tipping over.

[0055] In one embodiment, the long arm hook attachment 200 may be manufactured and installed in the following manner.

[0056] First, a first three-dimensional digital model is acquired representing the patient's dentition (either maxillary or mandibular) in a current dental configuration.

[0057] Next, the three-dimensional digital model of the first part 201 of the long arm hook attachment 200 is added to the pre-selected position on the pre-selected tooth in the first three-dimensional digital model to obtain a second three-dimensional digital model.

[0058] Then, the positive mold is made by using the second three-dimensional digital model control device (for example, stereolithography device).

[0059] Next, a hot pressing film forming process is used to press a film on the male mold to form a template. Figure 1 The shell-shaped dental appliance 100 shown is similar, being a one-piece shell that forms a first cavity for receiving teeth and a second cavity for receiving the main body of the long arm hook attachment.

[0060] Please refer to Figures 5A-5C ,in, Figure 5A is a front view of the second cavity 103' of the template in one embodiment (a view from the buccal side to the lingual side), Figure 5B for Figure 5A The left side view of the second cavity 103' is shown. Figure 5C for Figure 5A The second cavity 103' is shown in a cross-sectional view at BB.

[0061] The first cavity 103' comprises a first portion 1031' and a second portion 1033', wherein the width of the first portion 1031' (dimension in the mesiodistal direction) is greater than that of the second portion 1033', and the height of the first portion 1031' (dimension in the lingual-buccal direction) is consistent with that of the second portion 1033'.

[0062] The second portion 1033' forms a recess 1035' near the tooth surface, and its width d1 is smaller than the diameter of the long arm hook rod. In this way, when making the long arm hook attachment, the rod of the long arm hook can be separated from the gums, and then after the long arm hook attachment is bonded to the tooth surface, the end of the long arm hook (the end close to the hanging part) can be separated from the gums to avoid interfering with the gums.

[0063] Please refer to Figures 6A-6D ,in, Fig. 6A 1 is a front view (a view from the buccal side to the lingual side) of the second cavity 103″ of the template in another embodiment. Figure 6B for Fig. 6A The left side view of the second cavity 103" is shown. Figure 6C for Fig. 6A The cross-sectional view of the second cavity 103" at CC is shown. Fig.6D for Fig. 6A The second cavity 103" is shown in a cross-sectional view at DD.

[0064] and Figures 5A-5C The second cavity 103' shown is different in that Figures 6A-6D The height of the second part 1033" of the second cavity 103" shown in the figure gradually increases from the first end close to the first part 1031" to the second end away from the first part 1031", and the width of its recess 1035" gradually decreases from the first end to the second end, and the width d3 of the recess 1035" at DD is smaller than the width d2 at CC. In this way, when making the long arm hook accessory, the end of the rod of the long arm hook can be tilted to further leave the gums. For patients with protruding gums, this design can effectively prevent the end of the long arm hook from interfering with the gums.

[0065] In light of the present application, it can be understood that, in addition to the above two embodiments, the structure of the second cavity may have various variations. For example, the second portion of the second cavity may only be concave locally, for example, away from the first portion.

[0066] After obtaining the template, the long arm hook can be placed into the second cavity of the template, and the second cavity can be filled with the material of the main body of the long arm hook attachment that can be cured, such as light-curing resin.

[0067] In a preferred embodiment, the template can be worn on the patient's jaw or on a physical model of the patient's jaw, and the position of the long-arm hook rod can be fine-tuned according to the patient's gum condition to ensure that it does not interfere with the gum. Then, the material in the second cavity is cured to form a long-arm hook attachment.

[0068] Please refer to Figure 7 , schematically showing how to use the template 310 to make the long arm hook attachment 320. In order to more clearly show the relationship between the various parts, this view is a cross-sectional view along the dental arch curve at the rod 3233 of the long arm hook 323.

[0069] The template 310 is an integrated shell, forming a first cavity 311 for accommodating teeth and a second cavity 313 for accommodating the main body 321 of the long arm hook attachment 320. The second cavity 313 accommodates the head 323 and a part of the rod 3233 of the long arm hook 323, and is filled with the material used to form the main body 321 of the long arm hook attachment 320.

[0070] When the template 310 is worn on the tooth 331 (or tooth model), the surface of the tooth 331 and the second cavity 313 define the shape of the main body 321 of the long arm hook attachment 320. Before the material of the main body 321 of the long arm hook attachment 320 is cured, the angle of the rod 3233 can be adjusted according to the protrusion of the gum 333 to make it leave the gum 333. Then, the material of the main body 321 is cured (if a light-curing resin is used, it can be cured by light), and the long arm hook attachment 320 is formed.

[0071] The geometry of the second cavity 313 of the template 310 matches the main body 321 of the long arm hook attachment 320. The width of the second portion of the main body 321 is smaller than the first portion. Accordingly, the width of the second cavity 313 of the template 310 corresponding to the second portion of the main body 321 is smaller than the width of the second cavity 313 corresponding to the first portion of the main body 321. Such a design can bring two advantages. On the one hand, the narrower portion of the second cavity 313 can limit the lateral position of the long arm hook to prevent the long arm hook from lateral deflection in the finished long arm hook attachment. On the other hand, the narrower portion of the second cavity 313 can prevent the material of the main body 321 from overflowing before curing to a certain extent.

[0072] Then, the template can be removed, adhesive can be applied to the bonding surface of the long arm hook attachment, and the template can be worn on the patient's jaw. After the adhesive is cured, the template can be removed. At this time, the long arm hook attachment is precisely bonded to the predetermined position of the patient's teeth.

[0073] The geometric shape of the main body of the long-arm hook attachment is consistent with the second cavity of the template. Since the second part of the second cavity of the template forms a concave near the tooth surface, during the process of bonding the long-arm hook attachment using the template, the long-arm hook attachment can be retained in the second cavity of the template and is not easy to fall off, thereby facilitating bonding.

[0074] In the light of the present application, it can be understood that in addition to using a template similar to a shell-shaped dental appliance to make a long-arm hook attachment, a standard mold can also be used to make a long-arm hook attachment. The standard mold is basically the second cavity of the template. In order to adapt to different gum protrusion conditions, several standard molds can be provided, for example, the height of their second part (buccal and lingual dimensions) to respectively make long-arm hook attachments for different gum protrusion conditions.

[0075] The method of making the long arm hook attachment using the standard mold is similar to the method of making the long arm hook attachment using the template. First, the long arm hook is placed in the standard mold, then the material for forming the main body of the long arm hook attachment is filled in the standard mold, then the angle of the long arm hook is adjusted, then the overflowed material is scraped off, and finally, the material is solidified to form the long arm hook attachment.

[0076] Although various aspects and embodiments of the present application are disclosed herein, other aspects and embodiments of the present application will be apparent to those skilled in the art in light of the present application. The various aspects and embodiments disclosed herein are for illustrative purposes only and not for limiting purposes. The scope and subject matter of the present application are determined solely by the appended claims.

[0077] Likewise, various diagrams may illustrate exemplary architectures or other configurations of the disclosed methods and systems that aid in understanding the features and functions that may be included in the disclosed methods and systems. The claimed content is not limited to the exemplary architectures or configurations shown, and the desired features may be implemented with various alternative architectures and configurations. In addition, for flow charts, functional descriptions, and method claims, the order of blocks presented herein should not be limited to various embodiments that are implemented in the same order to perform the described functions, unless otherwise clearly indicated in the context.

[0078] Unless otherwise expressly noted, the terms and phrases used herein and their variations should be interpreted as open ended, not restrictive. In some instances, the appearance of broad words and phrases such as "one or more", "at least", "but not limited to", or other similar terms should not be understood as an intent or need to indicate a narrowing of the example where such broad terms may not be present.

Claims

1. A long arm hook attachment, used for bonding to the tooth surface to hang a traction member, comprising a long arm hook and a main body, wherein the long arm hook is extended to form a rod, the first end of the rod forms a hanging portion for hanging the traction member, a section of the long arm hook near the second end opposite to the first end is buried in the main body, the main body comprises a first part and a second part extending from the first part, the width of the first part of the main body is greater than the second part of the main body, the hanging portion of the long arm hook extends out of the second part of the main body, and the height of the second part of the main body is greater than the diameter of the rod of the long arm hook.

2. The long arm hook attachment according to claim 1, characterized in that: The long arm hook is an integral component made of metal material, and the main body is an integral component made of polymer material.

3. The long arm hook attachment according to claim 1, characterized in that: The long arm hook forms a head at the second end, the transverse dimension of the head is larger than the rod, and the head is buried in the second part of the main body.

4. The long arm hook attachment according to claim 1, characterized in that: The rod portion is located at a section of the second portion of the main body portion away from the tooth surface.

5. The long arm hook attachment according to claim 1, characterized in that: At least a section of the second part of the main body is narrowed inwardly near the tooth surface to form an inwardly retracted portion, and the minimum width of at least one point of the inwardly retracted portion in the extension direction of the second part of the main body is smaller than the diameter of the rod of the long arm hook. At the place where the minimum width of the inwardly retracted portion is smaller than the diameter of the rod of the long arm hook, the rod of the long arm hook is located on the side of the inwardly retracted portion away from the tooth surface.

6. The long arm hook attachment according to claim 5, characterized in that: The second part of the main body as a whole is narrowed inwardly near the tooth surface to form an inwardly retracted part, and the minimum width of the inwardly retracted part gradually decreases from one end of the second part close to the first part to the other end.

7. The long arm hook attachment according to claim 1, characterized in that: The height of the second portion gradually increases from one end of the second portion close to the first portion to the other end.

8. The long arm hook attachment according to claim 1, characterized in that: The first part forms a first inclined surface at one end close to the occlusal surface, so as to facilitate the wearing of the shell-shaped dental appliance.

9. The long arm hook attachment according to claim 1, characterized in that: Second inclined surfaces are formed on both sides of the second part of the first part at one end away from the occlusal surface to facilitate the removal of the shell-shaped dental appliance.

10. A shell-shaped dental appliance, which is an integral shell, forming a first cavity for accommodating a plurality of teeth and at least one second cavity for accommodating the main body of the long arm hook attachment as claimed in claim 1, wherein: The geometry of the second cavity matches the main body of the long arm hook attachment, and the second cavity extends to the edge of the shell-shaped dental appliance.

11. The shell-shaped dental appliance according to claim 10, characterized in that: The geometry of the first cavity conforms to the tooth in a first tooth configuration.

12. A method for making the long arm hook attachment as claimed in claim 1, comprising: Obtaining a mold containing the long arm hook and filled with the material of the main body, the mold comprising a cavity having a geometric shape consistent with the main body of the long arm hook attachment; as well as The material of the main body filled in the mold is solidified to obtain the long arm hook attachment.

13. The method for making a long arm hook attachment according to claim 12, characterized in that: It also includes: before solidifying the material of the main body in the mold, adjusting the angle of the rod of the long arm hook according to the protrusion of the patient's gums.

14. The method for making the long arm hook attachment according to claim 12, characterized in that: The material of the main body is a photocurable resin, and the curing is performed by light irradiation.

15. A mounting template for the long arm hook attachment as claimed in claim 1, which is an integral shell, forming a first cavity for accommodating a plurality of teeth and at least one second cavity for accommodating the main body of the long arm hook attachment as claimed in claim 1, wherein: The geometry of the first cavity matches the teeth of the patient under the current tooth configuration, and the geometry of the second cavity matches the main body of the long arm hook attachment.

16. A shell-shaped dental appliance, which is an integral shell, forming a first cavity for accommodating a plurality of teeth and at least one second cavity for accommodating a main body of a long arm hook attachment, wherein: The second cavity comprises a first portion close to the tooth crown and a second portion close to the gum, the first portion is wider than the second portion, and the second portion of the second cavity extends to the edge of the shell-shaped dental appliance.

17. The shell-shaped dental appliance according to claim 16, characterized in that: The long arm hook accessory includes a long arm hook and a main body, the long arm hook is extended to form a rod, the first end of the rod forms a hanging part for hanging a traction member, a section of the second end of the long arm hook opposite to the first end is buried in the main body, the main body includes a first part and a second part extending from the first part, the width of the first part of the main body is greater than the second part of the main body, the hanging part of the long arm hook extends out of the second part of the main body, and the height of the second part of the main body is greater than the diameter of the rod of the long arm hook.

18. The shell-shaped dental appliance according to claim 16, characterized in that: The height of the second part of the main body gradually increases from one end close to the first part of the main body to the other end.

19. The shell-shaped dental appliance according to claim 16, characterized in that: The first part of the main body forms a first inclined surface at one end close to the occlusal surface to facilitate wearing of the shell-shaped dental appliance.

20. The shell-shaped dental appliance according to claim 16, characterized in that: The first part of the main body forms second inclined surfaces on both sides of the second part at one end away from the occlusal surface, so as to facilitate the removal of the shell-shaped dental appliance.

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