47 results about "Impacted tooth" patented technology

The invention discloses an embedded tooth root bone adhesion feature recognition method and system based on deep learning, and relates to the field of medical image recognition, the position of an embedded tooth is detected based on a normalized image, image cutting of the embedded tooth and the surrounding area thereof is carried out along the long axis of a tooth body, the cutting area is a three-dimensional rectangular frame, and the three-dimensional rectangular frame is used as a matrix; classifying the cut images according to FDI tooth positions; performing hierarchical slicing on the classified images along the long axis of the tooth, taking the images after hierarchical slicing as input of an embedded tooth root bone adhesion feature recognition model, extracting depth features of the images in a feature extraction network ResNet50, removing a final full-connection layer of the ResNet50 model, retaining a feature map output by a convolutional layer, and identifying the embedded tooth root bone adhesion feature in the feature extraction network ResNet50; and inputting a feature map output by the convolutional layer into the region suggestion network and the classification and regression head to obtain a feature recognition result, including the probability that the embedded tooth root bone adhesion feature prediction candidate region belongs to the target category and the accurate position of the embedded tooth root bone adhesion feature candidate region bounding box.

This invention relates to the field of oral image analysis technology, specifically to a method for assisting in the identification of impacted teeth based on three-dimensional oral images. The method filters edge pixels in oral CT images to obtain enhanced images based on the degree of grayscale variation of these pixels and the shape, edge clarity, and grayscale distribution of their respective analysis areas. Then, based on the shape and tilt differences between the enhanced sagittal CT image and other tooth regions of the wisdom tooth in the three-dimensional oral model, the area of ​​the corresponding tooth region in the enhanced axial CT image, and the distance between adjacent tooth regions in the enhanced coronal CT image, the impacted wisdom tooth in the three-dimensional oral model is determined. This invention effectively improves the accuracy of impacted wisdom tooth identification.

The integrated adjustable impacted tooth auxiliary traction device comprises a base and an integrated adjustable traction mechanism. The base is connected to the surface of the impacted tooth. The integrated adjustable traction mechanism comprises an adjustable traction chain, at least two integrated traction mechanisms are arranged on the adjustable traction chain, the integrated traction mechanism comprises a connecting ring and a traction part, the connecting ring can be connected to form the adjustable traction chain, the traction part is provided with an opening, and the traction device can enter the traction part from the opening to continuously pull the impacted tooth. The integrated adjustable impacted tooth auxiliary traction device can not only build an adjustable chain structure to accurately control the length and direction of the free end, but also build an open hook structure of the free end through the integrated design of the opening, so that the closed orthodontic rubber band can be directly hung and pulled, the patient can complete the orthodontic rubber band hanging operation independently, and the clinical application is very convenient and fast.

The invention discloses a dynamic control system for crown cutting traction of impacted teeth. The dynamic control system comprises the following steps: acquiring the change trend of traction force along with time and the change trend of inflammation signals along with time in real time; controlling the micro excitation unit to apply micro vibration according to the change trend of the traction force and the change trend of the inflammation signal, and synchronously acquiring the periodic response waveform of the inflammation signal; s3, calculating a phase difference relative to micro excitation according to the periodic response waveform of the inflammation signal to obtain an inflammation phase sensitivity index; the maximum traction displacement increment and the minimum traction recovery interval allowed by the current traction period are calculated according to the degree that the inflammation phase sensitivity index deviates from the preset safe phase interval; according to each traction period, whether the accumulated traction displacement exceeds the maximum traction displacement increment or not and traction is executed when the traction interval is not smaller than the minimum recovery interval or not is judged; and dynamically adjusting an anti-inflammatory dose parameter based on the continuous change trend of the inflammation phase sensitivity index in the plurality of traction cycles.

The invention discloses a crown cutting and traction integrated tool for impacted teeth with inferior alveolar nerve injury risk, which utilizes a telescopic part made of a hydrogel material, has reversible performance of water absorption expansion and dehydration contraction, can realize micro-amplitude reciprocating deformation under the natural water environment change of an oral cavity or humidity control adjustment, and can be used for preventing and treating the impacted teeth with the inferior alveolar nerve injury risk. Therefore, slight stress stimulation in alternating directions is continuously applied to impacted teeth after traction is completed, periodontal ligament activity and an open state of a traction channel are maintained through reciprocating small force action, bridging hard connection between tooth roots and bone tissues is effectively prevented, initial resistance of second-time traction is remarkably reduced, and the secondary traction effect of the impacted teeth is improved. The operation risk of breaking through adhesion tissues again in clinic is reduced, the postoperative nerve traction complications and the tooth root absorption probability are further reduced, and the safety and efficiency of the whole treatment process are improved.

The invention belongs to the technical field of orthodontic instruments, and relates to an orthodontic device for drawing embedded impacted teeth, comprising: a fixing assembly comprising two groups of bands; the connecting assembly comprises a connecting piece; the stress application assembly comprises a traction hook and a spiral spring auxiliary bow, the spiral spring auxiliary bow is formed by continuously bending a traction wire in the axial direction of the traction wire to form a plurality of ring-shaped structures arranged at intervals, the bending direction of the ring-shaped structures is adjustable, and the number of the ring-shaped structures can be increased or decreased. Through the design that the traction wire is continuously bent in the traction direction to form the multiple spiral spring auxiliary arches which are arranged at intervals and are of the ring-shaped structures, the traction direction can be adjusted according to the bending direction of the ring-shaped structures, and the number of the ring-shaped structures can be adjusted according to the traction distance; the multiple ring-shaped structures arranged at intervals are used for providing continuous and soft traction force, the moving direction of teeth is accurately controlled, and the orthodontic treatment effect is guaranteed.

The invention belongs to the technical field of biomedical materials, and discloses a natural tooth composite material bone grafting scaffold for alveolar bone repair and a design and preparation method thereof. The method comprises the following steps: collecting orthodontic teeth, impacted teeth, multiple teeth, loose teeth and other natural teeth extracted in oral medical treatment, and performing technical treatment to obtain raw material powder; ball-milling and mixing the bioactive glass powder, the carbon-based material powder and the natural dental powder to obtain mixed powder; the mixed powder is used as a raw material, and the bone grafting scaffold is obtained through computer aided design and digital light processing technology 3D printing; and modifying the surface of the 3D printing bracket by using the polydopamine-carbon-based material composite coating to obtain the natural tooth composite material bone grafting bracket. The natural tooth composite material bone grafting scaffold obtained by the invention has good mechanical property, controllable degradation property and antibacterial property, and has good biocompatibility and osteogenesis efficiency.

The utility model provides a salix leaf drag hook for impacted tooth extraction surgery in oral and maxillofacial surgery, which relates to the technical field of medical instruments and comprises a holding part and a drag hook part, and the holding part is in a salix leaf shape; the draw hook part comprises a first draw hook and a second draw hook, the first draw hook and the second draw hook are symmetrically arranged at the two ends of the holding part, the first draw hook and the second draw hook are reversely folded in the same direction, the joint of the first draw hook and the holding part is in smooth transition, and the joint of the second draw hook and the holding part is arranged in a convex shape. According to the utility model, by designing the holding part in the shape of the willow leaf, flexible operation experience is provided, different hand types are adapted, and the stability is ensured; due to the double-end design, the drag hook can be operated at various angles, and the drag hook can flexibly adapt to impacted teeth at different positions; the head reflexed design can accurately pull soft tissues and expose the surgical field, and is suitable for complicated flap turning and boning operations; the micro-arc design enables the contact surface to be smoother, reduces compression on gingiva and soft tissue, and adapts to different soft tissue structures.

The utility model relates to the field of orthodontics, especially to adjustable embedded tooth auxiliary external traction device. The utility model provides an adjustable embedded tooth auxiliary external traction device which can move and adjust the traction block up and down, left and right and forward and backward according to requirements, and is convenient for flexible adjustment of traction point. The adjustable embedded tooth auxiliary external traction device comprises elastic bands and pull rings, the elastic bands are provided with two left and right elastic bands, and the elastic bands are connected with pull rings at the front part. The utility model adjusts the height position of the traction block through up and down movement of the adjusting rod, then moves and adjusts the adjusting rod forward and backward, adjusts the distance between the traction block and the user's lip, then moves and adjusts the traction block left and right on the adjusting rod, so that the traction block can be moved and adjusted up and down, left and right and forward and backward according to requirements, and the effect of convenient flexible adjustment of traction point is achieved.

A guiding device mounted on an impacted tooth, comprising a hook and a wire connected to the rear end of the hook. The hook has a curved shape and capable of passing through the transverse perforation of the impacted tooth. A method for passing the guiding device through the impacted tooth, by using the hook to guide the wire through the transverse perforation. A fixing member mounted on the impacted tooth, formed using the aforementioned method. A tool for assisting passing the guiding device through the impacted tooth, comprising a handle and a receiving portion connected to the handle, the receiving portion comprising a receiving hole and a slot. The receiving hole is capable of tightly receiving the hook of the guiding device, and the slot is in communication with the receiving hole, allowing the wire of the guiding device to pass through and extend out of the receiving portion.

The invention discloses an embedded tooth impacted tooth positioning traction simulation system based on a 5D bionic technology, which comprises a jaw model and a pre-operation simulation system, the jaw model is provided with an alveolar socket, a tooth root model and an embedded tooth model are detachably arranged in the alveolar socket, the jaw model is provided with a traction device in a mutual matching manner, and the traction device is provided with a tooth root model and an embedded tooth model. The traction device comprises two fixers and a traction arch wire; the two fixers are sleeved on the tooth root model; the traction arch wire is connected with the two fixers; a closed curve for hooping the embedded tooth model is arranged on the traction arch wire; a positioning guide plate is used in cooperation with the tooth root models, a positioning window is arranged on the positioning guide plate, the position of the positioning window corresponds to the position of the embedded tooth model, and a model taking device is used in cooperation with the closed curve. A real operation environment is provided for a doctor, the positioning guide plate accurately corresponding to the position of the embedded tooth is combined, the traction device can be guided to be in place rapidly and accurately, the precision and efficiency of preoperative planning are greatly improved, and the operation risk is reduced.

The invention discloses a dental ultrasonic osteotome, relates to the technical field of ultrasonic osteotomes, and aims to solve the technical problems that an existing ultrasonic osteotome is not matched with low-position impacted teeth and gaps of embedded impacted teeth are increased. The working tip comprises a working tip body, the working tip body comprises a rod part connected with a handle, a neck part and a head part are sequentially arranged at the end, away from the handle, of the rod part, the head part is of a bent arc-shaped structure, the included angle between the axis of the head part and the axis of the neck part is 60-100 degrees, and a blade face is arranged on the head part. The head adopts the bent arc-shaped structure, and the head and the neck are vertically or obliquely arranged, so that on one hand, the head can bypass the top surfaces and the side surfaces of the teeth (similar to covering the teeth) through the bent arc-shaped structure, contact with the alveolar bone of the teeth and increase the gap of the alveolar bone part, and the difficulty of increasing the gap of the alveolar bone is reduced; and on the other hand, as the head part adopts the bent arc-shaped structure, when the covering and buckling teeth are in contact with the alveolar bone of the teeth, the shape of the tooth root can be fit to increase the gap of the alveolar bone, and the gap increasing effect is better.

The present application relates to the field of dental correction tools, in particular to a device for traction of impacted teeth. The device is composed of a traction hook and an appliance. The traction hook is adhered to the crown of the impacted tooth to be tractioned. The traction hook is composed of an adhesive accessory and a ligature wire. One end of the ligature wire is fastened to the adhesive accessory, and the other end of the ligature wire is free and curved into a hook. The appliance is composed of an elastic traction wire and a retaining device. One end of the elastic traction wire is embedded in the retaining device, and the other end of the elastic traction wire is curved and connected to the free curved end of the ligature wire of the traction hook. The device can reasonably adjust the traction direction of the impacted teeth in three-dimensional space, and can correct the impacted teeth in different dentition periods. The device has low requirements for the anchorage teeth, is simple to manufacture, low in price, and has remarkable effects.

This invention relates to a method, device, and medium for displaying mechanical information for risk warning during impacted tooth extraction. The method includes: Step S1: Obtaining the three-dimensional modeling results of each tissue unit; Step S2: Obtaining the modeling results of each tooth segment unit; Step S3: Constructing the tooth segment and its contact constraints with surrounding tissues; Step S4: Based on the constructed contact constraints, combined with the overall finite element stiffness matrix and operational load, solving for the displacement response of each finite element mesh; Step S5: Based on the displacement response of each finite element mesh and the shape function, obtaining the displacement matrix of each element, and further obtaining the strain tensor of each element; Step S6: Based on the constitutive matrix of the tissue material corresponding to each element and the strain tensor, obtaining the stress tensor of each element; Step S7: Comparing the stress tensor of each element with its pre-configured threshold and assigning color values ​​to the finite element mesh of each element. Compared with the prior art, this invention has the advantages of real-time performance and high accuracy.

The utility model relates to the technical field of oral medical equipment, and provides a device for pulling out a horizontal impacted cross section root of a mandibular third molar, which comprises a suction component, a pulling component and a limiting component, the suction component is detachable and covers a second molar to form a limiting part, and the limiting component limits the pulling component. The extraction component is used for extracting the root parts of the segmented teeth; the suction component comprises a suction groove, an inflation pipeline, an inflation pump and a supporting air bag, one end of the inflation pipeline is connected with the supporting air bag, the other end of the inflation pipeline is connected with the inflation pump to form inflation parts, the suction groove covers the second molar in a buckled mode, the inflation parts are arranged on the two sides of the suction groove, and the suction groove is attached to the second molar; the limiting component is arranged on the upper end face of the suction groove and detachably connected with the pulling-out component. The novel device for pulling out the transverse root of the horizontal impacted tooth has the advantages of low risk of inferior alveolar nerve injury, high patient comfort, strong oral cavity tissue protection capability and simplicity and convenience in operation.

A dental instrument includes a handle and an extension portion, the extension portion has a frontal protrusion that is used to hang an elastic traction ligature. An impacted tooth traction device includes a first bracket for being fastened to an impacted tooth, and a second bracket for being fastened to an anchor body, and the aforementioned elastic traction ligature that is used to connect the first bracket with the second bracket. A method for installing the impacted tooth traction device includes: fastening the first bracket to the impacted tooth, fastening the second bracket to the anchor body, and to connect the elastic traction ligature to the first and the second brackets after the elastic traction ligature is pulled to a certain length.

A magnetic traction device for impacted tooth, comprising a first magnetic component fixed to a normal tooth and a second magnetic component fixed to an impacted tooth. There is an attractive magnetic force between the first and second magnetic components, thereby pulling the impacted tooth toward the direction of the normal tooth where the first magnetic component is located.

The invention relates to the technical field of deep learning, and discloses a caries automatic classification auxiliary decision-making system, which comprises a controller, an image acquisition module, an auxiliary display module, an image labeling module, an image segmentation module, a disease identification module, a disease extraction module and a classification storage module. An image segmentation module carries out tooth identification and segmentation on the labeled original image by adopting an improved Mask R-CNN to obtain the form and position of each tooth, and the form and position of each tooth are superposed on the original image to serve as an identification image; and the disease identification module is used for carrying out dental caries, periapical periodontitis, root bifurcation lesion and impacted tooth identification on the identification image by adopting YOLO-Teth. According to the method, the form and the position of each tooth are obtained through the Mask R-CNN model, meanwhile, tooth lesions are identified through the YOLO-Teth network model, various oral lesions can be identified, the identification accuracy is improved, finally, disease images are displayed and stored in a classified mode, an auxiliary diagnosis means is provided for dentists, and the actual requirements of clinical diagnosis are met.

The present invention discloses a traction member and invisible braces for tooth traction, and relates to the field of oral medical technology. The traction member of the present invention is used for invisible braces, and the traction member is an elastic member. The traction member is connected between the tooth to be corrected and the braces, and the connection portion between the traction member and the support component is provided with at least two clamping members along its length direction; the braces is provided with a mounting hole, the second end of the traction member is placed in the mounting hole, and the clamping member is clamped and fixed to the edge of the mounting hole. The traction member can be used in conjunction with the invisible braces, and the wrapping property of the invisible braces is used to form the entire dental arch as a whole, and together provide support and traction for the impacted tooth. In this way, there is no need to add orthodontic implant support, and invasive operations are reduced. The traction member is fixed by clamping members at different positions, and the traction force of its elastic adjustment section can be adjusted to improve the adaptability of the traction member; in addition, the present invention can be applied to the adjustment of the elongation movement after the impacted tooth erupts, which makes up for the deficiency of the invisible braces in the elongation movement.

The invention belongs to the field of medical instruments, and relates to a saliva suction device for impacted tooth extraction. The saliva suction device comprises a saliva suction working end and a negative pressure control device, the saliva suction working end is fixedly arranged in a molar rear pad area, the saliva suction working end comprises three saliva suction parts, the three saliva suction parts are respectively arranged on point positions needing saliva suction, and the negative pressure control device is used for controlling the negative pressure of each saliva suction part; the saliva suction parts are distributed at each saliva suction point in the molar rear pad area, and the saliva suction negative pressure of each saliva suction part is intensively controlled through the negative pressure control device, so that the saliva suction device does not move across an operation area at all, and the operation area operation and view of a doctor are not blocked; and the effect of fixing and sucking saliva away from the hand can be achieved.

The application relates to the field of orthodontics, in particular to a vertical molar fixing device, which comprises a fixing ring, a traction connecting rod and a traction member. The fixing ring is matched with a target premolar, the fixing ring is used for sleeving the premolar, one end of the traction connecting rod is connected with the side wall of the outer circumferential surface of the fixing ring, the other end of the traction connecting rod extends away from the fixing ring, a pulling hook is arranged at the end of the traction connecting rod away from the fixing ring, one end of the traction member is detachably connected with the pulling hook, and the other end of the traction member is connected with the target tooth; the traction member pulls the target tooth when being tensioned. The fixing ring is arranged on the premolar to fix the traction connecting rod. The traction member connected with the traction connecting rod is used for pulling the supernumerary tooth. The fixing ring has a simple structure and can be directly fixed on the tooth without the aid of additional screws, so that the installation steps and the device structure are simplified, and the experience of the patient after installation is improved.

This invention provides a guided orthodontic device for mandibular impacted teeth treatment, belonging to the field of oral medical device technology. It includes a lingual bar, multiple retention rings, at least one abutment, and at least one guide rod. The lingual bar is a continuous arc-shaped metal wire extending along the lingual side of the mandibular dental arch. The lingual side of each retention ring is fixedly connected to the lingual bar. The lower end of the abutment is fixed to the lingual bar, and its upper end extends upward and has an abutment portion for contacting the abutment tooth surface. The proximal end of the guide rod is fixed to the lingual bar, and its distal end extends towards the oral vestibule, with a connecting portion at its end for attaching a traction component. This invention provides stable, distributed surface anchorage through multiple retention rings, effectively transmits the gingival force experienced by the device to the abutment tooth through the abutment, further enhancing anchorage stability. The flexible, cantilevered guide rod with a connecting portion at its end enables control of the traction direction of the impacted tooth.

This invention discloses a method for segmenting impacted teeth and neural tubes based on media regions, belonging to the field of medical image processing technology. The method includes the following steps: S1000, preparation; S2000, model structure optimization; S3000, model training; S4000, continued training of the temporary model; S5000, segmentation prediction of impacted teeth and neural tubes. This invention improves the accuracy and fit of boundary positions, significantly enhances the segmentation accuracy and stability of low-media regions, and solves the technical problem of accurate semantic segmentation of structural overlap, media blurring, and boundary discontinuity regions in dental CBCT images.

Embodiments of the present invention provide a method and apparatus for determining the tooth number of a tooth. The method comprises: acquiring first dental crown data and second dental crown data of a same patient in at least one treatment stage; on the basis of the degree of overlap between the dental crown of a first tooth in the first dental crown data and the dental crown of a second tooth in the second dental crown data, determining the tooth number of the first tooth having a degree of overlap satisfies a first set threshold as the tooth number of the second tooth; and on the basis of a positional relationship between the dental crown of the second tooth having the tooth number and the dental crown of a third tooth, determining the tooth number of the third tooth, wherein the third tooth is any tooth other than the second tooth having the tooth number in the second dental crown data. By matching the tooth numbers on the basis of the first dental crown data and the second dental crown data, the tooth number of a corresponding permanent tooth in the second dental crown data and the tooth number of an impacted tooth in the second dental crown data are determined, thereby improving the efficiency and accuracy of determining the tooth number of a tooth.

The novel traction device comprises a bone nail body, the lower end of the bone nail body is connected with a nail head portion used for being implanted into a bone in a matched mode in a clamped mode, a connecting piece used for assisting traction is installed at the upper end of the bone nail body, and the end of the connecting piece is connected with an elastic piece; and the end part of the elastic piece is fixed on the surface of the dental crown of the impacted tooth through a bonding accessory. According to the novel traction device for the impacted tooth micro-implant, the problem of slippage of the connecting piece is effectively avoided through sleeving and hanging connection of the hanging ring and the bone nail body, the connecting body adopts a necklace-shaped metal chain and can penetrate through an oral mucosa, so that a stress application part at the tail end is exposed in an oral cavity, and a doctor can conveniently operate the novel traction device; the tail end is designed to be a metal round buckle similar to a tongue buckle, so that an elastic rubber chain is convenient to hang.

The invention relates to the technical field of oral cavity image analysis, in particular to an impacted tooth auxiliary identification method based on an oral cavity three-dimensional image. The method comprises the following steps: filtering edge pixel points in an oral CT image to obtain an enhanced image according to the gray level change degree of the edge pixel points in the oral CT image and the shape, the edge clearness degree and the gray level distribution of an analysis area where the edge pixel points are located; according to the shape difference and inclination degree difference of the wisdom teeth in the three-dimensional model of the oral cavity in the enhanced image of the sagittal CT image of the oral cavity and other tooth areas, the area of the corresponding tooth area of the wisdom teeth in the enhanced image of the axial CT image of the oral cavity and the distance between the adjacent tooth areas in the enhanced image of the coronal CT image of the oral cavity, the tooth area of the wisdom teeth in the three-dimensional model of the oral cavity is obtained; and determining the impacted wisdom teeth in the oral cavity three-dimensional model. According to the invention, the recognition accuracy of the impacted wisdom teeth is effectively improved.

The utility model relates to the field of medical auxiliary instruments, and discloses an impacted tooth tractor. According to the device, the tail ends of the side face frame, the lower jaw frame and the transverse connecting frame are movably connected with a connecting block, the surface of the connecting block is provided with a plurality of through holes and two threaded holes, and the surfaces of the two threaded holes are in threaded connection with a first fastening bolt and a third fastening bolt correspondingly; a second fastening bolt is in threaded connection with a through hole in the middle of the surface of the connecting block, the side face frame, the lower jaw frame and the transverse connecting frame penetrate through the surface of the connecting block through the through holes, and the side face frame, the lower jaw frame and the transverse connecting frame are movably arranged through the multiple through holes formed in the surface of the connecting block. The second fastening bolt arranged in a matched mode can facilitate adjustment and threaded fixation of the transverse connecting frame, meanwhile, the formed threaded holes are matched with the first fastening bolt and the third fastening bolt so that adjustment and threaded fixation of the side face frame and the lower jaw frame can be facilitated, and through the structural arrangement, a doctor can conveniently adjust according to the face shape of a patient.

The application provides a traction device for impacted teeth and a preparation and operation method, comprising a traction hook, a shaped traction auxiliary bow, a prop, a transpalatal bar (TPA), a buccal tube, an anterior incline bend and a loop bend. The device has flexible traction direction, can flexibly add the position of the traction hook according to the required traction direction, and solves the problem of strong foreign body sensation and discomfort when the patient wears the traditional traction device. The bilateral molars provide anchorage, reducing the influence on the single tooth around the impacted anterior tooth. The application solves the problems of insufficient anchorage and single traction direction in the prior art, improves the correction efficiency, and has the characteristics of simple preparation, comfortable wearing and the like.

The invention discloses a lower jaw impacted tooth traction device, and belongs to the technical field of dental medical equipment. The mandibular impacted tooth traction device comprises a shell and a clamping mechanism, and further comprises a jacking mechanism and a traction mechanism, wherein the jacking mechanism is used for pressing one end, close to a bracket, of a push spring on an arch wire; the threading mechanism comprises an extrusion part, a driving wheel and a driven wheel, a sliding groove in the length direction of the bracket is formed in the shell, a first sliding block is slidably connected into the sliding groove, the extrusion part is used for applying extrusion force towards one end of the push spring to the first sliding block, and the side wall, away from one end of the bracket, of the push spring is clamped between the driving wheel and the driven wheel; the driving mechanism is used for driving the driving wheel to rotate so as to drive the push spring to rotate along the own rotation direction, and the end, close to the bracket, of the push spring is wound on the arch wire under the action of the jacking mechanism. According to the mandibular impacted tooth traction device disclosed by the invention, a new push spring can be mounted, so that the disassembly arch wire is prevented from loosening after being re-disassembled and re-assembled.