Dental instrument

Abstract

The utility model provides a dental instrument which comprises a shell-shaped body with a plurality of tooth containing cavities, the shell-shaped body further comprises an extension part and a traction part, the extension part is formed by extending the edges of the tooth containing cavities towards the gingiva direction, the traction part protrudes from part of the surface of the extension part towards the far-tooth direction to form a cavity structure, and in addition, the traction part is connected with the extension part. The traction part and the edge of the extension part are arranged at an interval; the side surface of the traction part is provided with a containing cavity used for hanging a traction piece, and when the traction device is worn, the extension part covers and wraps part of gingiva. The traction part in each embodiment of the utility model not only can replace the function of an anchorage nail to provide anchorage force or orthodontic force, but also solves a series of negative effects that in the prior art, an implanting nail needs to be driven into a tooth root, and trauma is caused to the interior of the mouth of a patient.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of orthodontics, in particular to a dental appliance. BACKGROUND

[0002] Traditional tooth correction technology usually uses brackets and steel wires to move teeth to achieve the purpose of correcting malocclusion. However, such brackets and steel wires are too many and too obvious, which greatly affects the appearance, and can cause gum inflammation, tooth demineralization and discoloration, and other oral damage. On this basis, the invisible tooth correction system emerged as the times require, which uses an invisible shell-shaped tooth corrector made of elastic transparent high polymer material to realize the movement of teeth. The entire correction process almost does not affect daily life and social interaction, and since the patient can self-apply and remove, it is convenient for daily oral health maintenance, and also makes the entire correction process more convenient.

[0003] In the field of invisible correction, the shell-shaped corrector also needs to be used in cooperation with the anchorage nail (also known as the bone nail) to complete the correction for cases with severe bone deformities. For example, the anchorage nail is an indispensable correction accessory for cases requiring retraction of anterior teeth, forward movement of posterior teeth, lowering of teeth, uprighting of individual teeth, and correction of ectopic teeth. However, since the anchorage nail is made of metal and needs to be punched into the tooth root during use, the use of the anchorage nail will bring a series of negative effects to the patient, such as: tooth discomfort, if the direction of the anchorage nail is inclined and the distance to the adjacent tooth root is close, it will cause swelling and discomfort of the tooth; removal difficulty, if the position of the anchorage nail is deep, the surface will be covered by the proliferated gum tissue, making it extremely difficult to remove the anchorage nail, and sometimes it will break; alveolar bone damage, the anchorage nail is punched into the alveolar bone, which will damage the alveolar bone, and during the recovery process, it may cause swelling and pain of the gum; gum problems, the end of the anchorage nail is exposed on the surface of the attached gum, which is easy to retain food residues, soft dirt, accumulate plaque, cause gum swelling and bleeding, and over time, inflammation occurs around the anchorage nail, which can cause loosening and shedding.

[0004] Therefore, it is necessary to provide a more comfortable and non-invasive dental appliance that can perform the same function as the anchorage nail. CONTENT OF THE UTILITY MODEL

[0005] The purpose of the embodiment of the present application is to provide a new type of dental appliance that avoids the use of anchorage nails in clinical practice and realizes the invisibility of the function of the anchorage nail, and provides a more comfortable and non-invasive dental appliance that can perform the same function as the anchorage nail.

[0006] To achieve the above object, the embodiment of the present application provides a dental appliance, comprising a shell-shaped body with a plurality of tooth receiving cavities, the shell-shaped body further comprising an extension part and a traction part, the extension part being formed by extending edges of the tooth receiving cavities in the direction of the gum, the traction part being formed by protruding part of the surface of the extension part in the direction of the distal tooth to form a cavity structure, and the traction part being arranged at a distance from the edges of the extension part; a side surface of the traction part is provided with a containing cavity for suspending a traction member, wherein the extension part covers and wraps part of the gum when worn.

[0007] As a preference, the side surface where the containing cavity is located is a first surface, and a surface of the traction part opposite to the first surface is a second surface, wherein a projection of the first surface in the direction of traction, close to one end of the extension part, is a first projection, and a projection of the first surface in the direction of traction, away from one end of the extension part, is a second projection, and the first projection is closer to the second surface than the second projection.

[0008] As a preference, the direction in which the first surface extends from the end close to the extension part to the end away from the extension part is a first direction, and the angle between the first direction and the direction of traction is greater than 90° and less than or equal to 150°.

[0009] As a preference, the first surface and the second surface are arranged in parallel to each other.

[0010] As a preference, the distance between the edge of the extension part and the corresponding gum line in the direction of the gum and the jaw is between 0.5 mm and 2.5 mm.

[0011] As a preference, the shortest distance between the traction part and the edge of the extension part is greater than or equal to 0.5 mm.

[0012] As a preference, the protruding height of the traction part in the protruding direction is between 1.5 mm and 2 mm.

[0013] As a preference, the extension part covers the buccal gingival surface and the lingual gingival surface at the same tooth position in the posterior dental area, the extension part on the buccal side is provided with a plurality of first traction parts, the extension part on the lingual side is provided with a plurality of second traction parts, and the two ends of the traction member are respectively suspended by the first traction part and the second traction part, wherein the occlusal surface of the tooth receiving cavity on the path of the traction member is provided with a slot, and the size of the slot is greater than the size of the traction member.

[0014] As a preference, the containing cavity is a groove structure formed by the side surface of the traction part being concave in the direction of traction; or the containing groove is a containing cavity formed by the side surface of the traction part.

[0015] Preferably, the height of the accommodation cavity in the protruding direction is not more than 1 / 2 of the height of the traction part in the protruding direction.

[0016] The dental instrument provided by the utility model has at least the following beneficial effects compared with the prior art:

[0017] The purpose of the present technique is to improve the existing shape of the invisible aligner, and a prolonging portion is arranged on the shell-shaped body corresponding to the gum portion with a plurality of tooth receiving cavities, and the traction part is located on the prolonging portion, and the side surface of the traction part is provided with an accommodation cavity for suspending the traction member, the orientation of the accommodation cavity can be set according to different treatment requirements, and in each embodiment of the present application, the traction part can not only replace the function of the anchorage pin to provide anchorage force or treatment force, but also solve a series of negative effects caused by the implant pin in the prior art, such as the need to be punched into the tooth root and the trauma caused to the patient's mouth. Moreover, since the traction part and the shell-shaped body are an integral structure, when the traction part provides the anchorage force, all the teeth wrapped by the shell-shaped body can be used as a whole to provide the anchorage force, the expression of the force is greatly improved, and the treatment expression rate is improved.

[0018] In addition, in some embodiments of the present application, the side surface where the accommodation cavity is located is a first surface, the surface of the traction part opposite to the first surface is a second surface, the projection of one end of the first surface close to the prolonging portion in the traction direction is a first projection, the projection of the other end of the first surface away from the prolonging portion in the traction direction is a second projection, and the first projection is closer to the second surface than the second projection. By such arrangement, the first surface as a whole is inclined to the side of the prolonging portion of the adjacent portion, so that the first surface has the function of preventing the traction member from separating from the traction part, thereby avoiding the risk that the traction member separates from the traction part during use, the traction force cannot be effectively applied, and the traction member is mistakenly swallowed by the patient after separating. BRIEF DESCRIPTION OF DRAWINGS

[0019] One or more embodiments are exemplarily illustrated by the pictures in the drawings corresponding thereto, and the exemplarily illustrations do not constitute a limitation on the embodiments, and the elements with the same reference numerals in the drawings represent similar elements, unless otherwise specified, and the drawings do not constitute a proportional limitation.

[0020] Figure 1 is a wearing schematic diagram of the dental instrument in some embodiments of the present application;

[0021] Figure 2 is Figure 1 is a cross-sectional schematic view along A-A' at the corresponding position of the traction part in some embodiments of the present application;

[0022] Figure 3 is Figure 1 is an enlarged schematic view of the structure of the traction part in some embodiments of the present application;

[0023] Figure 4In another embodiment of this application, the dental instrument is... Figure 1 Schematic diagram of the structure under section A-A';

[0024] Figure 5 yes Figure 4 A magnified view of a portion of region D in the middle;

[0025] Figure 6 yes Figure 4 A magnified view of a portion of region D in the middle;

[0026] Figure 7 This is a partial enlarged view of the location of the traction part when the dental instrument is worn, according to another embodiment of this application;

[0027] Figure 8 In another embodiment of this application, the dental instrument is... Figure 1 Schematic diagram of the structure under section A-A';

[0028] Figure 9 This is a schematic diagram of the traction unit from one perspective in another embodiment of this application;

[0029] Figure 10 yes Figure 9 A schematic diagram of the assembly of the traction unit and the traction component from one perspective in the embodiment;

[0030] Figure 11 In another embodiment of this application, the dental instrument is... Figure 1 Schematic diagram of the structure under section A-A';

[0031] Figure 12 yes Figure 11 A schematic diagram of the dental instrument and traction device after assembly in the embodiment. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been presented in the various embodiments of this application to enable readers to better understand this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various changes and modifications based on the following embodiments. The division of the various embodiments below is for the convenience of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0033] The "back teeth region" mentioned in various embodiments in the present application is defined according to the classification of teeth in the 2nd edition of "Introduction to Oral Medicine" published by Peking University Medical Publishing House, pages 36-38, including premolars and molars, which are teeth 4-8 in FDI marking method, and teeth in the front teeth region are teeth 1-3 in FDI marking method. The teeth in the front teeth region include central incisors, lateral incisors and canines.

[0034] The shell-shaped appliance is a computer three-dimensionally designed and produced invisible and aesthetic dental correction mechanical device, usually worn on the teeth in the mouth, composed of high polymer materials, such as TPU, PETG or both materials, etc., which can generate force to change the deformed jaw, misaligned teeth and periodontal tissue, and is beneficial to the normal growth and development of the teeth and jaw. The shell-shaped appliance uses the principle of biomechanics to correct the deformed teeth, applies a gentle and persistent biological force through a series of shell-shaped appliances, slowly moves the teeth, and restores the teeth to the normal position to arrange the teeth in order. In the correction process, other accessories are usually used or different structures are set on the shell-shaped appliance to exert additional correction force on the teeth.

[0035] In the prior art, in the field of invisible correction, the shell-shaped appliance also needs to be used in cooperation with the anchorage nail (also known as the bone nail) to complete the correction for cases with severe skeletal deformities. However, the use of the anchorage nail brings a series of negative effects to the patient, such as tooth discomfort, swelling and discomfort of the tooth if the direction of the anchorage nail is inclined and the distance to the adjacent tooth root is close, removal difficulty, if the position of the anchorage nail is deep, the surface is covered with proliferative gum tissue, which causes great difficulty in removing the anchorage nail, sometimes even breakage, alveolar bone damage, the anchorage nail is punched on the alveolar bone, which damages the alveolar bone and may cause swelling and pain of the gum during the recovery process, gum problems, the end of the anchorage nail is exposed on the surface of the attached gum, which is easy to retain food residues, soft dirt, accumulate plaque, cause gum swelling and bleeding, and inflammation around the anchorage nail may occur after a long time, which may cause loosening and falling off.

[0036] The present application provides a dental instrument, comprising a shell-shaped body having a plurality of tooth receiving cavities, the shell-shaped body further comprising an extension part and a traction part, the extension part is formed by the edge of the tooth receiving cavity extending towards the gum direction, the traction part is formed by the part surface of the extension part protruding towards the distal tooth direction to form a cavity structure, and the edge of the extension part is arranged at a distance from the traction part; the side surface of the traction part is provided with a containing cavity for suspending a traction member, wherein the extension part covers and wraps part of the gum when worn. The traction part in each embodiment of the present application not only can replace the function of the anchorage nail to provide anchorage force or correction force, but also solves the problem that the implant nail needs to be punched into the tooth root in the prior art, which causes a series of negative effects such as trauma in the patient's mouth.

[0037] The embodiments of the present application will be described below with reference to the accompanying drawings.

[0038] Referring to Figure 1 , Figure 2 and Figure 3 , the present application provides a dental appliance, which comprises a shell-shaped body 1 having a plurality of tooth receiving cavities 11. The shell-shaped body 1 can be a shell-shaped appliance having a correction function as described above, or can be a shell-shaped retainer consistent with the current tooth layout of the patient. Of course, in some cases, the plurality of tooth receiving cavities 11 can be part of the teeth corresponding to a single jaw, or all the teeth of a single jaw. The shell-shaped body 1 further comprises an extension 13 formed by the edge of one or more tooth receiving cavities 11 extending towards the gum, and a traction part 12 formed by the partial surface of the extension 13 protruding towards the distal tooth to form a cavity structure, and the traction part 12 is arranged at a distance from the edge 131 of the extension 13. This arrangement can avoid the problem of the edge 131 of the extension 13 being deformed by the traction force, so that the traction part 12 loses the traction function. The side surface of the traction part 12 is provided with a receiving cavity 121 for suspending a traction member, and the orientation of the receiving cavity 121 can be set according to different correction needs. When worn, the extension 13 covers and wraps part of the gum. The traction part 12 not only provides anchorage force or correction force instead of the function of the anchorage pin, but also solves the problem of the implant pin in the prior art, which needs to be punched into the tooth root, causing a series of negative effects such as trauma to the patient's mouth. Moreover, since the traction part 12 and the shell-shaped body 1 are an integral structure, when the traction part 12 provides anchorage force, all the teeth wrapped by the shell-shaped body 1 can be provided as a whole to provide anchorage force, greatly improving the expression of force, thereby improving the correction expression rate.

[0039] In an embodiment, referring to Figure 4 and Figure 5 , the traction part is taken as an example at the position of the posterior teeth. When the traction part 12 is arranged on the extension 13, the side surface where the receiving cavity 121 is located is a first surface 123, and the surface of the traction part 12 opposite to the first surface 123 is a second surface 124. The first surface 123 can be the surface close to the tooth side or the surface away from the tooth side or the mesial surface of the traction part 12 or the distal surface of the traction part 12, Figure 5 of which the surface away from the tooth side is taken as an example.

[0040] It can be understood that when the traction part 12 is a cylinder or a circular truncated cone as a whole, the side surface of the traction part 12 is a cylindrical or circular truncated cone side surface, the first surface 123 is a part of the curved side surface, and the second surface 124 is the remaining part of the curved side surface. Wherein, the projection of the first surface 123 close to one end of the extension part 13 in the traction direction X is the first projection, and the projection of the first surface 123 away from one end of the extension part 13 in the traction direction is the second projection. The first projection is closer to the second surface 124 than the second projection.

[0041] With reference to the specific Figure 5 As shown, the first projection is point M, and the second projection is point N. Point N is closer to the second surface 124 than point M. In this way, the end of the first surface 123 away from the extension part 13 can block the traction member from slipping off, and has a certain limiting effect on the traction member. In this way, the first surface 123 as a whole is inclined toward one side of the extension part 13, so that the first surface 123 has the effect of blocking the traction member from disengaging from the traction part 12, thereby avoiding the risk that the traction member disengages from the traction part 12 during use, resulting in ineffective application of traction force, and the risk that the traction member is mistakenly swallowed by the patient after disengaging.

[0042] Of course, the traction part 12 as a whole can also be a prism or a truncated prism. In this case, the side surface of the traction part 12 is a corresponding prism surface or a truncated prism surface. It can be understood that when the traction part 12 is a quadrangular prism or a quadrangular truncated cone as a whole, the first surface 123 can be the mesial surface, the distal surface, the surface close to the teeth side, or the surface away from the teeth side of the truncated prism. When the traction part 12 is a multi-prism or a multi-truncated prism as a whole, the first surface 123 can be a plurality of surfaces close to the mesial surface, a plurality of surfaces close to the distal surface, a plurality of surfaces close to the teeth side, or a plurality of surfaces away from the teeth side of the truncated prism. The specific setting can be determined according to different correction methods. For example, taking vertical traction as an example, and the traction part 12 as a whole is a quadrangular prism, the first surface 123 is a surface away from the teeth side, and the first surface 123 as a whole is inclined toward the adjacent extension part 13. In the traction process, the first surface 123 on the distal tooth side can effectively block the traction member from falling off.

[0043] Further preferably, with reference to the specific Figure 6As shown, the direction in which the first surface 123 extends from the end near the extension portion 13 to the end away from the extension portion 13 is the first direction E, and the angle β between the first direction E and the traction direction X is greater than 90° and less than or equal to 150°. This arrangement ensures that the traction member can enter the area formed between the first surface 123 and the extension portion 13 during assembly, and also ensures that during traction, the first surface 123 can prevent the traction member from detaching from the traction portion 12, thereby avoiding the risk of the traction member detaching from the traction portion 12 during use, resulting in ineffective application of traction force, and the risk of the traction member being accidentally swallowed by the patient after detachment.

[0044] Further preferably, when the first projection is closer to the second surface 124 than the second projection, the first surface 123 and the second surface 124 are arranged parallel to each other. In one case, referencing... Figure 6 As shown, the first surface 123 and the second surface 124 are parallel planes, meaning that the distance between the first surface 123 and the second surface 124 is equal everywhere along the traction direction of the traction part 12. In another case, refer to... Figure 7 As shown, the first surface 123 and the second surface 124 are parallel curved surfaces. This design ensures that the part where the traction part 12 and the extension part 13 are connected has a larger size, preventing deformation of the traction part 12 under the action of traction force during use.

[0045] In another embodiment, reference Figure 8 As shown, the distance L1 between the edge 131 of the extension 13 and the corresponding gingival line in the gingival direction is between 0.5mm and 2.5mm. The advantage of this arrangement is that the extension 13 has sufficient area to accommodate the traction part 12, so that the traction part 12 has sufficient size to suspend the traction member and can maintain sufficient rigidity during traction.

[0046] Continue to refer to Figure 8 As shown, the edges 131 of the traction part 12 and the extension part 13 are spaced apart, and the shortest distance L2 between the edges of the traction part 12 and the extension part 13 is greater than or equal to 0.5mm. This arrangement can prevent the edge 131 of the extension part 13 from warping and deforming under the action of traction force, thus avoiding the problem that the traction part 12 will also deform and the traction member will detach from the traction part 12 and lose its traction function, or that the position of the traction part 12 will change, causing the direction of the corrective force to deviate from the design direction, resulting in an unsatisfactory corrective effect.

[0047] In another embodiment, reference Figure 9As shown, the protruding height H1 of the traction part 12 in the protruding direction is between 1.5mm and 2mm. The protruding arrangement of the traction part 12 from the surface of the shell body 1 can increase the size of the traction part 12 on the shell body 1, and can provide greater traction strength. However, the protruding height of the traction part 12 should not be too high. The protruding height H1 between 1.5mm and 2mm can reduce the scratching of the traction part 12 on the oral mucosa, and improve the comfort of the treatment.

[0048] Further preferably, with reference to Figure 9 As shown, the height H2 of the accommodating cavity 121 in the protruding direction is not more than 1 / 2 of the height H1 of the traction part 12 in the protruding direction. The accommodating cavity 121 is arranged closer to the shell body 1. This arrangement can make the position of the traction force closer to the shell body 1 after the suspension of the traction member, and the area of the traction part 12 connected to the shell body 1 can jointly bear the traction force, so that the traction part 12 is not easy to deform. Figure 10 As shown, when the direction of the traction force (the stretching direction of the traction member 3 in the figure) is not perpendicular to the protruding direction, especially when it is inclined away from the teeth, the accommodating cavity 121 is arranged closer to the shell body 1. This can make the part 12a of the traction part 12 (the part at the free end of the traction part 12) away from the shell body 1 larger in size, and less likely to deform under the action of the traction force, thereby ensuring the structural stability of the traction part 12 during the traction process.

[0049] In another embodiment, with reference to Figure 11 and Figure 12 As shown, the extension part 13 covers the buccal gingival surface and the lingual gingival surface at the same tooth position in the posterior dental area. The extension part 13 on the buccal side is provided with a plurality of first traction parts 12a, and the extension part 13 on the lingual side is provided with a plurality of second traction parts 12b. The traction member 3 is suspended on the first traction part 12a and the second traction part 12b at both ends, respectively. The occlusal surface of the tooth accommodating cavity 11 on the path of the traction member 3 is provided with a slot 111, and the size of the slot 111 is greater than the size of the traction member 3. During the traction process, the traction member 3 is suspended on the first traction part 12a and the second traction part 12b, respectively, and the traction member 3 is limited in the slot 111 area on the tooth surface for generating a pressure force on the directly contacted teeth. With reference to Figure 11 and Figure 12In the shown embodiment, the first traction part 12a and the second traction part 12b are in the form of a quadrangular prism, the first traction part 12a is arranged on the side surface of the first traction part 12a away from the tooth (i.e. the first surface of the first traction part 12a is the side surface of the first traction part 12a away from the tooth), and the second traction part 12b is arranged on the side surface of the second traction part 12b away from the tooth (i.e. the first surface of the second traction part 12b is the side surface of the second traction part 12b away from the tooth). This arrangement can make the traction force coincide with the desired direction of the tooth, without generating other directional components, so that the traction force, i.e. the pressure force, can be effectively applied to the tooth. In some cases, the first traction part 12a and the second traction part 12b are arranged on the buccal side and the lingual side of the same tooth in the posterior region, respectively, to complete the pressure of a single tooth in the posterior region, or in some cases, the first traction part 12a and the second traction part 12b are arranged on the buccal side and the lingual side of different teeth in the posterior region, respectively, to achieve the interaction of the jaws.

[0050] The traction part 12 in the present application can be a cavity structure integrally formed with the shell body 1 by a hot stamping film process, and the accommodation cavity 121 is a groove structure formed by the inward recess of the side surface of the traction part 12, and the traction member such as rubber band is fixed at the groove structure. Integrally forming can improve the stability of the connection between the two, reduce the process flow and thus improve the preparation efficiency of the dental instrument.

[0051] In addition, the accommodation cavity is an opening structure formed on the side surface of the traction part, and the opening structure on the traction part 12 can be that in the process of processing the appliance, the patient's tooth model data is imported into the system to generate a tooth model at each step, and the system places a virtual traction part on the tooth model at each step according to the medical treatment scheme. When placed, the bottom surface of the traction part is in contact with the tooth surface or the gum, and the opening direction is opposite to the traction direction. After the 3D printed tooth model and the film are placed on the solid tooth model to obtain the shape of the appliance by film pressing, the opening structure is obtained by cutting process, and the preferred way is that the opening structure is an arc-shaped opening, which reduces the problem of stress concentration leading to deformation of the traction part in the traction process. It can be that in the process of processing the appliance, the patient's tooth model data is imported into the system to generate a tooth model at each step, and the system places a traction part on the tooth model at each step according to the medical treatment scheme. When placed, the bottom surface of the traction part is in contact with the tooth surface or the gum, and the opening direction is opposite to the traction direction. After the 3D printed tooth model and the film are placed on the solid tooth model to obtain the shape of the appliance by film pressing, the opening structure is obtained by cutting process, and the preferred way is that the opening structure is an arc-shaped opening, which reduces the problem of stress concentration leading to deformation of the traction part in the traction process.

[0052] It should be explained that the above embodiments can be freely combined to form different new embodiments according to the needs without causing contradictions, and the embodiments formed after the combination are within the protection scope of the present application, and are not described here in order to save the length of the application text.

[0053] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, can make a number of improvements and refinements, these improvements and refinements should also be considered within the scope of the present application.

[0054] Similarly, the above is only a specific embodiment of the present application, but the protection scope of the present application is not limited to this, any skilled in the art within the scope of the present application disclosed technology, can easily think of changes or replacement, should be covered within the scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A dental appliance comprising a shell body having a plurality of tooth receiving cavities, the shell body further comprising an extension portion and a traction portion, characterized in that, The extension part is formed by extending the edge of the tooth receiving cavity in the gingival direction, the traction part is formed by protruding part of the surface of the extension part in the distal direction to form a cavity structure, and the traction part is arranged at a distance from the edge of the extension part; the side surface of the traction part is provided with a containing cavity for suspending the traction member, wherein when worn, the extension part covers and wraps part of the gum.

2. The dental instrument of claim 1, wherein, The side surface where the containing cavity is located is a first surface, and the surface of the traction part arranged opposite to the first surface is a second surface, wherein the projection of the first surface close to one end of the extension part in the traction direction is a first projection, the projection of the first surface away from one end of the extension part in the traction direction is a second projection, and the first projection is closer to the second surface than the second projection.

3. The dental instrument of claim 2, wherein, The direction in which the first surface extends from the end close to the extension part to the end away from the extension part is a first direction, and the angle between the first direction and the traction direction is greater than 90° and less than or equal to 150°.

4. The dental instrument of claim 2, wherein, The first surface and the second surface are arranged parallel to each other.

5. The dental instrument of claim 1, wherein, The distance between the edge of the extension part in the gingival direction and the corresponding gum line is between 0.5mm and 2.5mm.

6. The dental instrument of claim 5, wherein, The shortest distance between the traction part and the edge of the extension part is greater than or equal to 0.5mm.

7. The dental instrument of claim 1, wherein, The protrusion height of the traction part in the protruding direction is between 1.5mm and 2mm.

8. The dental instrument of claim 1, wherein, The extension part covers the buccal gingival surface and the lingual gingival surface at the same tooth position in the posterior region, the buccal extension part is provided with a plurality of first traction parts, the lingual extension part is provided with a plurality of second traction parts, and the traction member suspends the first traction part and the second traction part at both ends, respectively, wherein the occlusal surface of the tooth receiving cavity on the path of the traction member is provided with a slot, and the size of the slot is greater than the size of the traction member.

9. The dental instrument of claim 1, wherein, The containing cavity is a groove structure formed by concave forming the side surface of the traction part in the traction direction; or the containing cavity is an opening structure formed by the side surface of the traction part.

10. Dental instrument according to claim 1 or 9, characterized in that The height of the containing cavity in the protruding direction is not more than 1 / 2 of the height of the traction part in the protruding direction.

Images