Method and apparatus for providing orthodontic appliance having self-ligating features via tie wings

Abstract

An orthodontic bracket having self-ligating features is disclosed. The base bracket includes a plurality of tie wings disposed on the mesial and distal sides and an archwire slot positioned therebetween. A ligating element is detachably coupled to the tie wings to selectively retain an archwire within the archwire slot. The tie wings serve both as ligature supports and structural guides for the ligating mechanism.

Description

METHOD AND APPARATUS FOR PROVIDING ORTHODONTIC APPLIANCE HAVING SELF-LIGATING FEATURES VIA TIE WINGSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority under 35 U.S.C § 119(e) to U.S. Provisional Application, U.S.S.N. 63 / 657,704, filed June 07, 2024, which is incorporated herein by reference.BACKGROUND OF THE INVENTION1. Field of the invention

[0002] The exemplary embodiment(s) of the present invention relates to the field of medical instrument. More specifically, the exemplary embodiment(s) of the present invention relates to processing and fabricating orthodontic appliances containing information.2. Description of the related art

[0003] Orthodontic brackets are widely used in clinical practice to apply corrective forces to misaligned teeth through engagement with archwires. For non-customized or customized orthodontic brackets, the mechanism to tie the orthodontic archwire is an important component of the bracket design and function. In general, there are two ways to retain the orthodontic archwire in the slot of the bracket: non-self-ligating with metal wire or elastic loop and self-ligating with a movable cover to stop the orthodontic archwire from dislodging from the slot. Some designs employ metal doors that rotate or slide over the slot, while others utilize spring clips that deform to engage or release the wire. While these designs offer improved clinical efficiency, they may still involve complex assembly, high manufacturing costs, or limited compatibility with customized brackets.

[0004] Certain self-ligating mechanisms rely on dedicated channels or hinges embedded in the base bracket to accommodate the ligating elements. This may restrict design flexibility or interfere with the configuration of tie wings, particularly when attempting to miniaturize the bracket or apply it to customized dental anatomy. In many cases, the tie wings serve only for ligation purposes and do not participate in the guiding or retaining of the ligating element.

[0005] Moreover, existing self-ligating designs often require the ligating structure to be pre-assembled or permanently attached to the base bracket, limiting the options for replacement, reconfiguration, or simplified manufacturing. Some mechanisms may also require complex machining or high-precision molding to ensure reliable movement or retention of the liga ting element.

[0006] On the other hand, in terms of materials, 3D printing technologies can currently be used to print orthodontic brackets and tubes, either non-customized or customized, either to be bonded to the buccal or lingual side of the tooth (“brackets” means non-customized, customized, buccal or lingual orthodontic brackets and tubes hereafter). Common materials used for orthodontic brackets are polymer materials, composite materials, metals, and ceramic materials. Specialized printing materials can be used with different printing technologies to print the orthodontic brackets in specific materials that arc supposed to provide strength, aesthetics, and biocompatibility for clinical use.

[0007] There remains a need for an orthodontic bracket design in which the tie wings not only retain the archwire but also function as mechanical guides or structural interfaces for a ligating element. Such a design should be compatible with removable or replaceable ligating elements, be adaptable to various manufacturing methods, and allow straightforward operation without excessive structural complexity.SUMMARY

[0008] The present invention relates to an orthodontic bracket having self-ligating features, in which a ligating element is configured to retain an archwire within an archwire slot formed in a base bracket. The base bracket comprises a plurality of tie wings disposed on the mesial side and the distal side. Unlike conventional brackets where tie wings serve solely as ligature points, the present invention enables the tie wings to also function as guiding and coupling structures for various types of ligating elements. The invention provides multiple embodiments to achieve self-ligation through different structural combinations.

[0009] In one embodiment of the present invention, a detachable ligating element is provided. The ligating element in this embodiment is a cover, having four clips, each disposed at a comer of a rectangular base. Two clips are arranged on the mesial side and two on the distal side. These clips are configured to elastically engage with corresponding tie wings formed on the base bracket. The tie wings are arranged in opposing pairs and are shaped to provide undercuts or engagement surfaces for the clips. When mounted, the cover spans across the archwire slot and closes it from above, thereby retaining the archwire in place. The detachable nature of the clips allows for easy opening and reattachment of the cover during treatment. This embodiment emphasizes a mechanically secure but removably coupled cover design that is compatible with various manufacturing methods, including injection molding or 3D printing.

[0010] In another embodiment disclosed herein, the ligating element is a preformed ligating wire consisting of a long section, a short section, and a bent-over section. The long section is inserted beneath the tie wings on both the mesial and distal sides, engaging their undercut structures. The short section is configured to traverse across the archwire slot and press against the archwire for retention. The base bracket in this embodiment includes an inclined ligating wedge disposed between the occlusal side and the archwire slot. As theligating wire is slid from the occlusal side toward the gingival side, the short section moves along the wedge and is eventually stopped by a designated stopper structure. This stopper provides a positional limitation. This configuration allows self-ligation through resilient wire deformation and guided movement without requiring a complex cover.

[0011] In yet another embodiment of the present invention, a sliding ligating cover moves between open and closed positions in a direction from the occlusal side to the gingival side. The base bracket is modified to include a central dovetail block protruding upward and a plurality of tie wings, each pair of tie wings comprising a core and a cap. The ligating element includes a dovetail channel that engages the dovetail block, ensuring guided and laterally stabilized sliding.

[0012] During closure, the ligating cover slides along the dovetail track and is stopped by the caps of the tie wings. A ligating ledge formed on the cover moves over the archwire slot and presses down on the archwire to retain it securely in place. The caps serve both as physical stops and as gripping points for manual handling. This embodiment offers a stable, reusable, and tool-friendly ligation system based on structural interlocking and guided motion.

[0013] Additional features and benefits of the exemplary embodiment(s) of the present invention will become apparent from the detailed description, figures, and claims set forth below.BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The exemplary embodiment(s) of the present invention will be understood more fully from the detailed description given below and from the accompanying drawings of various embodiments of the invention, which, however, should not be taken to limit the invention to the specific embodiments, but are for explanation and understanding only.

[0015] FIG. 1 A is a schematic diagram illustrating an orthodontic bracket with a ligating element of the first embodiment in accordance with the present invention.

[0016] FIG. IB is a top view illustrating the orthodontic bracket with the ligating element of the first embodiment in accordance with the present invention.

[0017] FIG. 2A is a schematic diagram illustrating the base bracket of the first embodiment in accordance with the present invention.

[0018] FIG. 2B is a side view illustrating the base bracket of the first embodiment in accordance with the present invention.

[0019] FIG. 3 is a schematic diagram illustrating the ligating element of the first embodiment in accordance with the present invention.

[0020] FIG. 4A is a schematic diagram illustrating the base bracket engaged with a ligating element and an archwire in the closed configuration of the second embodiment in accordance with the present invention.

[0021] FIG. 4B is a side view illustrating the base bracket engaged with a ligating element and an archwire in the closed configuration of the second embodiment in accordance with the present invention.

[0022] FIG. 5A is a schematic diagram illustrating the base bracket with a ligating wedge of the second embodiment in accordance with the present invention.

[0023] FIG. 5B is a side view illustrating the base bracket with the ligating wedge of the second embodiment in accordance with the present invention.

[0024] FIG. 6A is a schematic diagram illustrating the ligating element of the second embodiment in accordance with the present invention.

[0025] FIG. 6B is a side view illustrating the ligating element of the second embodiment in accordance with the present invention.

[0026] FIG. 7 A is a cross-sectional view illustrating the base bracket engaged with the ligating element and the archwire in the open configuration of the second embodiment in accordance with the present invention.

[0027] FIG. 7B is a cross-sectional view illustrating the base bracket engaged with the ligating element and the archwire in the closed state of the second embodiment in accordance with the present invention.

[0028] FIG. 8A is a schematic diagram illustrating that the base bracket further comprises two cores, two caps, and a dovetailed block of the third embodiment in accordance with the present invention.

[0029] FIG. 8B is a side view illustrating that the base bracket further comprises two cores, two caps, and the dovetail block of the third embodiment in accordance with the present invention.

[0030] FIG. 9A is a schematic diagram illustrating the ligating element with a dovetail channel and a ligating ledge of the third embodiment in accordance with the present invention.

[0031] FIG. 9B is a schematic diagram illustrating the ligating element with the dovetail channel and the ligating ledge of the third embodiment in accordance with the present invention.

[0032] FIG. 9C is a side view illustrating the ligating element with the dovetail channel and the ligating ledge of the third embodiment in accordance with the present invention.

[0033] FIG. 10A is a schematic diagram illustrating the base bracket engaged with the ligating element and the archwire in the open configuration of the third embodiment in accordance with the present invention.

[0034] FIG. 1 OB is a schematic diagram illustrating the base bracket engaged with the ligating element and the archwire in the closed configuration of the third embodiment in accordance with the present invention.

[0035] FIG. 10C is a cross-sectional view illustrating the base bracket engaged with the ligating element and the archwire in the open configuration of the third embodiment in accordance with the present invention.

[0036] FIG. 10D is a cross-sectional view illustrating the base bracket engaged with the ligating element and the archwire in the closed configuration of the third embodiment in accordance with the present invention.DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] Embodiments of the present invention are described herein in the context of a method and / or apparatus for processing and fabricating orthodontic devices.

[0038] The purpose of the following detailed description is to provide an understanding of one or more embodiments of the presen t invention. Those of ordinary skills in the art will realize that the following detailed description is illustrative only and is not intended to be in any way limiting. Other embodiments will readily suggest themselves to such skilled persons having the benefit of this disclosure and / or description.

[0039] In the interest of clarity, not all of the routine features of the implementations described herein are shown and described. It will, of course, be understood that in the development of any such actual implementation, numerous implementation-specific decisionsmay be made in order to achieve the developer’s specific goals, such as compliance with application- and business-related constraints, and that these specific goals will vary from one implementation to another and from one developer to another. Moreover, it will be understood that such a development effort might be complex and time-consuming but would nevertheless be a routine undertaking of engineering for those of ordinary skills in the art having the benefit of embodiment(s) of this disclosure.

[0040] Various embodiments of the present invention illustrated in the drawings may not be drawn to scale. Rather, the dimensions of the various features may be expanded or reduced for clarity. In addition, some of the drawings may be simplified for clarity. Thus, the drawings may not depict all the components of a given apparatus (e.g., device) or method. The same reference indicators will be used throughout the drawings and the following detailed description to refer to the same or like parts.

[0041] For non-customized or customized orthodontic brackets, the mechanism to tie the orthodontic archwire is an important component of the bracket design and function. In general, there are two ways to retain the orthodontic archwire to the slot of the bracket, nonself-ligating with metal wire or elastic loop, and self-ligating with a movable cover to stop the orthodontic archwirc from dislodging from the slot. There's no clear advantage of one category of bracket versus the other in terms of clinical efficacy based on scientific evidence. But one group of doctors prefers self-ligating brackets more than non-self-ligating ones for reasons such as ease of use, simplistic appearance, and ease of cleaning. There is a myriad of bracket designs in both categories. However, this invention is about a bracket design that uses tie wings in the base bracket as guide rails for the self-ligating function. The mechanism consisted of the tie wings and the ligating feature can close and open the slot for the archwire. To produce the base bracket and ligating feature, different manufacturing processes can be used such as casting, polymer injection molding, metal injection molding, ceramic injectionmolding, metal 3D printing, and ceramic 3D printing. The ligating mechanism can be applied to both customized orthodontic brackets and non-customized orthodontic brackets.

[0042] Many 3D printing technologies can be used to print orthodontic brackets and tubes, either non-customized or customized, either to be bonded to the buccal or lingual side of the tooth ("‘brackets” means non-customized, customized, buccal or lingual orthodontic brackets and tubes hereafter). Common materials used for orthodontic brackets are polymer materials, composite materials, metals, and ceramic materials. Specialized printing materials can be used with different printing technologies to print the orthodontic brackets in specific materials that are supposed to provide strength, ascetics, and biocompatibility for clinical use.

[0043] Non-customized brackets are designed with a series of parameters a.k.a. in-out, angle of torque, angulation, rotation offset, slot depth, slot height, and slot length, that are built in to fit all patients’ teeth (the parameters are defined as in ISO 27020-2019 hereafter). The brackets are designed to facilitate the movement and alignment of teeth using preset parameters called the prescription, such as MBT, Roth, etc. The parameters of a prescription for a bracket vary by tooth type and are based on the generic anatomy and size of different tooth types, a.k.a. upper central incisor, upper lateral incisor, upper canine, upper premolars, upper molars, lower central incisor, lower lateral incisor, lower caninc, lower premolars, and lower molars. The pad (or called base by ISO 27020-2019) of the non-customized bracket is not customized to the patient’s tooth anatomy. Nevertheless, the pad of non-customized bracket can be designed in different shapes and sizes to fit generic types of teeth, a.k.a. upper central incisor, upper lateral incisor, upper canine, upper premolars, and upper molars, lower central incisor, lower lateral incisor, lower canine, lower premolars, and lower molars.

[0044] The process of designing and manufacturing customized orthodontic brackets starts with the intraoral scanning of a patient's teeth. After the patient's teeth are scanned, the digital file of the scan is imported into a treatment planning software that segments the digitalfile of the scan into individual teeth that can be programmed to move from the initial position to the final position. At the final position, teeth are lined up according to clinical standards accepted by the doctor or dental professional.

[0045] At this final position, based on the specific parameters of the brackets a.k.a. in- out, angle of torque, angulation, rotational offset, slot depth, slot height, and slot length, the treatment planning software will automatically place a set of bracket templates on the teeth. The template for each type of tooth is different based on the generic size and anatomy of that type of tooth a.k.a. upper central incisor, upper lateral incisor, upper canine, upper premolars, and upper molars, lower central incisor, lower lateral incisor, lower canine, lower premolars, and lower molars. The treatment planning software will customize the parameters of the bracket listed above based on the final position of the teeth and the placement of the brackets on the teeth constrained and conditioned by the chosen archwire shape by the doctor, which results in all the slots in brackets are lined up along the preformed archwire shape at the final position of teeth.

[0046] The other portion of the orthodontic bracket that is customized to the patient's teeth is the pad of each template. As the anatomy of this specific patient is considered and used to customize the pad for each template, the pad will well fit the patient-specific tooth where the template is placed. Then the digital model of customized brackets can be output into a format that is transferable and compatible to a 3D printer.

[0047] The operator will bond the bracket to the tooth surface one by one until all teeth have a bracket bonded. After the bracket is bonded to the tooth surface, the pad of the bracket is attached to the tooth enamel by a special dental adhesive that is supposed to provide bonding strength to endure the oral environment and orthodontic forces throughout the treatment. Then the operator will place the orthodontic archwire in the slots of the brackets and retain the archwire in the slot. For non-self-ligating brackets, a metal ligation wire or aplastic loop is used to retain the archwire in the slot. For self-ligating brackets, a ligating mechanism is presented to retain the archwire in the slot. In conventional non-self-ligating or self-ligating brackets, if there are tie wings, they are on the occlusal side and the gingival side of the bracket. The current invention has multiple embodiments that all involve the usage of tie wings on the mesial and distal sides of the base bracket as guide rails for the self-ligating mechanism.

[0048] For simplicity of explanation, the present invention assumes that the bracket is for an upper right posterior tooth. For a person in the art of orthodontics, it is straightforward to figure out the same concept, principle, and technology that are applicable to brackets for other dentitions.

[0049] As used herein, the terms "mesial", "distal", "gingival", and "occlusal" are defined relative to the orientation of the bracket as mounted on a tooth. The "mesial side" refers to the direction toward the midline of the dental arch, the "distal side" refers to the direction away from the midline, the "occlusal side" faces the chewing surface, and the "gingival side" faces toward the gum line.

[0050] As used herein, the term “ligating element” refers to a removable or preassembled component configured to selectively retain the archwire within the archwire slot of the base bracket. The ligating element engages with the tie wings provided on the base bracket, but does not include the tie wings themselves. Depending on the embodiment, the ligating element in the present invention may include a clip-on cover, a ligating wire, or a sliding cover, and is configured to engage with tie wings and retain the archwire by mechanical coupling, sliding, or clamping mechanisms.

[0051] In the first embodiment of this invention, as shown in Figs. 1 A and I B, the selfligating bracket 1 of the present invention comprises a base bracket 10 and a ligating element20, wherein the ligating element 20 is detachably mounted to the base bracket 10 for retaining an archwire 30. Preferably, the means of connection between the base bracket 10 and the ligating element 20 includes, but is not limited to, sliding, hooking, locking, clamping, coupling, or engagement. The means of connection between the base bracket 10 and the ligating element 20 is merely an example and may be suitably adapted by those having ordinary knowledge in the field in accordance with the embodiment(s) of the present invention as required. The present invention illustrates some methods in the following embodiment. More preferably, the shapes of the base bracket 10 and the ligating element 20 correspond to each other, but are not limited to the same shape. The shapes of the base bracket 10 and the ligating element 20 may be suitably adjusted by those having ordinary knowledge in the field of the present invention using common sense and necessity provided that the base bracket 10 and the ligating element 20 can be detachably combined.

[0052] As shown in Figs. 2A and 2B, the base bracket 10 exemplarily includes a distal side 40, a mesial side 41, a gingival side 42, and an occlusal side 43. It will be recognized that these designations are relative and informational, and alternative embodiments may be positioned in other orientations within the mouth of the patient while remaining within the scope of the embodiments as disclosed herein. The base bracket 10 includes a bonding pad 11, a plurality of tie wings 12, and an archwire slot 13. The bonding pad 11 is disposed on the rear surface of the base bracket 10. Specifically, the bonding pad 11 is positioned opposite to the tie wings 12 and the archwire slot 13 and is configured to face the outer surface of a patient’s tooth. The bonding pad 11 serves as a contact interface for securing the base bracket 10 to the tooth surface via an adhesive material. The bonding pad 11 may be integrally formed with the base bracket 10 or separately attached. The bonding pad 11 may be connected to the base bracket 10 by bonding, such as bonding, welding, molding, or integral molding, wherein the bonding pad 11 may be an independent component and then assembled, or may beintegrally manufactured during injection molding or 3D printing. The bonding surface of the bonding pad 1 1 may include texture or roughening structures to enhance adhesive retention. In some examples, the shape of the bonding pad 30 is customized based on the anatomical contour of the tooth. The geometry of the bonding pad 11 takes into account the relative position of the archwire 30 to ensure orthodontic precision. The bonding pad 1 1 can be made of the same material as the base bracket 10, such as ceramic, metal, composite material, or different materials that can be used to achieve shock absorption, elasticity, or better adhesion effect. Preferably, in this embodiment, the number of the tie wings 12 is four. The number and shape of the tie wings 12 can be modified as needed. In particular, the two tie wings 12 are arranged in opposing pairs, with one pair disposed near the gingival side 42, and the other pair of tie wings 12 disposed near the occlusal side 43. The archwire slot 13 is positioned between the two pairs of tie wings 12 and is laterally adjacent to the two pairs of tie wings 12. The archwire slot 13 in accordance with the present invention, is used to guide the archwire 30; therefore, the shape, depth, diameter, material, and size of the archwire slot 13 described herein can be adjusted according to the cross-sectional shape and diameter of the archwire 30 accommodated in the archwire slot 13. In the practical application of orthodontic treatment, the use of archwires is usually gradual. In the initial phase, light, flexible nickel-titanium wires are used to apply gentle, continuous force to align teeth and relieve crowding. In the later stages, stiffer gingival wires, such as rectangular stainless steel gingival wires, are used to define the shape of the dental arch and guide precise tooth movement.

[0053] As shown in Figs. 1A, IB, and 3, the ligating element 20 in this embodiment can be a cover. The cover has a base 21 and four clips 22. The four clips 22 are respectively arranged at the four comers of the base 21 , and the clips 22 are arranged opposite to each other. Specifically, two clips 22 of the four clips 22 are on the distal side 40, and the other two clips 22 are on the mesial side 41. Each clip 22 is detachably engaged with the tie wing 12 ofthe base bracket 10, that is, each tie wing 12 is configured to receive each clip 22. Preferably, the shape and size of each clip 22 and each tie wing 12 correspond and can be buckled together, so that the ligating element 20 can be detachably connected to the base bracket 10 through the four clips 22. The ligating element 20 as a whole can be made by casting, injection molding, and / or 3D printing. The ligating element 20 could be like a cover but does not need to be pre-assembled onto the base bracket.

[0054] When the archwire slot 13 of the base bracket 10 is to be closed by the ligating element 20, the operator can buckle the ligating element 20 shown in Fig. 3 onto the base bracket 10 as shown in Figs. 2A and 2B. The operator may buckle from either the mesial side 41 or the distal side 40 according to the position of the tie wing 12 of the base bracket 10. After all clips 22 clamp the tie wings 12 respectively, the interference between the clips 22 and the tie wings 12 generates sufficient contact force and frictional force to retain the position of the ligating element 20. Therefore, the ligating element 20 can retain the archwire 30 in the archwire slot 13. When the operator wants to change or remove the archwire 30 during or at the end of the treatment, the operator will use small dental tools to disengage the clips 22 from the tie wings 12. In practice, the operator can start from any clip 22 and then disengage all four clips 22 to remove the ligating element 20 from the base bracket 10.

[0055] In the second embodiment, as shown in Figs. 4A and 4B, the base bracket 10 has two tie wings 12 on the mesial 41 and two tie wings 12 on the distal sides 40, and the archwire slot 13 is closed by the ligating element 20. As shown in Figs. 5 A and 5B, the base bracket 10 further comprises a ligating wedge 14 and a stopper 15. The ligating wedge 14 is a protrusion located on a pair of tie wings 12 near the occlusal side 43. Specifically, the ligating wedge 14 is located near the archwire slot 13, and its thickness decreases from the gingival side 42 toward the occlusal side 43 to form a high end 141 near the archwire slot 13, a low end 142, and a sloped surface 143 between the high end 141 and the low end 142. That is, theligating wedge 14 is triangular or trapezoidal in shape as shown in the side view, Fig. 5B in accordance with the present invention. As shown in Figs. 7 A and 7B, the stopper 15 is a protrusion disposed on the gingival side 42 and has an abutting surface 151 formed at one end thereof close to the archwire slot 13, and an end opposite to the abutting surface 151 protrudes from the base bracket 10 to form a hook 152, that provides anchor points for inter-arch or intra-arch elastics or power chains. Specifically, a height hl of the abutting surface 151 of the stopper 15 is greater than a height h2 of the high end 141 of the ligating wedge 14, as shown in the side views. The base bracket 10 can be made by casting, injection molding, or 3D printing. As shown in Figs. 6A and 6B, the ligating element 20 in this embodiment can be a ligating wire 23. The ligating wire 23 can be made by metal wire bending or polymer injection molding. The ligating wire 23 comprises a long section 231, a short section 232, and a bent-over section 233. The bent-over section 233 connects the long section 231 and the short section 232 to form a closed loop. The long section 231 is inserted in the undercut of tie wings 12 for the mesial side 41 and the distal side 40; the short section 242 covers the archwire slot 13 to retain the archwire 30 in the archwire slot 13; the bent over section 243 is detachable and partially overlay the two tie wings 12 on the occlusal side 43. As shown in Figs. 4A and 4B, the ligating wire 23 needs to be pre-assembled onto the base bracket 10 by expanding the long section 231 in the mesial-distal direction such that the distance between the mesial side 41 and the distal sides 40 of the long section 231 becomes large enough to fit underneath the tie wings 12. As the long section 231 is inserted underneath the tie wings 12, the short section 232 lands on the lower end 142 of the ligating wedge 14, referring to the open status. The spring force in the ligating wire will prevent it from dislodging from underneath the tie wings. However, the spring force will stil l allow the sliding motion of the ligating wire within the undercuts of the tie wings. That is to say, the tie wings 12 are configured to receive a ligating wire 23.

[0056] To close the archwire slot 13 with the archwire 30 inside, as shown in Figs. 7 A and 7B, the operator will push the ligating wire 23 toward the archwire slot 13 to cover it. In particular, the operator can push the bent-over section 233 and / or the short section 232 of the ligating wire 23 along the ligating wedge 14 toward the gingival side 42. The tie wings 12 serve as guide rails for the ligating wire 23 to slide underneath. When the ligating wire 23 is going onto the slope 143 of the ligating wedge 14, it will deflect until it overcomes the highest point of the ligating wedge 14 and snaps to the other side of the highest point, and the short section 242 slides above the archwire slot 13 and rests against the abutting surface 151 of the stopper 15. Since the height hl of the abutting surface 151 of the stopper 15 is greater than the height h2 of the high end 141 of the ligating wedge 14, the abutting surface 151 of the stopper 15 can prevent the short section 242 from sliding further and complete the archwire slot 30 closure for retaining the archwire 30 inside of the archwire slot 30.

[0057] Similarly, when the operator wants to change the archwire 30 during the treatment or remove the archwire 30 at the end of the treatment, the operator will use the small dental tools to lift the short section 232 of the ligating wire and push it onto the slope 143 of the ligating wedge 14. Then the operator can pull on the short section 232 down the slope 143 of the ligating wedge 14 toward the occlusal side 43 to fully open the archwire slot 30.

[0058] In the third embodiment, as shown in Figs. 8A and 8B, each pair of tie wings 12 further comprises a core 121 and a cap 122. Each cap 122 is integrally formed on top of the core 121 and extends outwardly (in a distal-mesial direction) to form a protruding surface. Specifically, one of the caps is located near the gingival side 42, and the other cap is located near the occlusal side 43. The caps 122 of the tie wings 12 serve as the stop for the ligating element 20, while the cores 121 of the tie wings 12 serve as the guide rail for the clips 22 of the ligating element 20 to snap on and slide along. The base bracket 10 further comprises adovetail block 16, which is located on the core 121 , and the occlusal side 43. The dovetail block 16 protrudes upwardly from the core 121 and has a dovetail-shaped profile in crosssection. As shown in Figs. 9A to 9C, the ligating element 20 further comprises a leading surface 23, a dovetail channel 24, and a ligating ledge 25. The leading surface 23 is located at the bottom near the occlusal side 43, and the leading surface 23 facilitates the alignment and initial insertion of the ligating element 20 on the base bracket 10. The dovetail channel 24 is centrally disposed along the occlusal-gingival direction and near the occlusal side 43. The dovetail channel 24 is detachably engaged with the dovetail block 16 of the base bracket 10 to guide the ligating element 20 during sliding and provide lateral stability. The ligating ledge 25 is a ledge formed near the gingival side 42 extending toward the occlusal side 43. The ligating cover can be made by casting, injection molding, 3D printing, or by metal bending. The ligating element 20 needs to be pre-assembled onto the base bracket 10.

[0059] As shown in Figs. 10A to 10D, when the ligating element 20 is assembled onto the base bracket 10, the four clips 22 will be snapped to the cores 121 of the tie wings 12. As being snapped to the cores 121 of the tie wing 12, each clip 22 will be deflected such that the distance between them in mesial-distal direction is increased to overcome the dimension of the cores 121 of the tie wings 12 along the same direction. As the ligating element 20 is snapped onto the cores 121 of the tie wings 12, the dovetail channel 24 is clear of the dovetail block 16 of the base bracket 10. After the clips 22 are engaged onto the cores 121 of the tie wings 12, the interference between the clips 22 and the core 121 of the tie wings 12 will create enough contact force and frictional force to prevent the ligating element 20 from dislodging. However, this frictional force will still allow the sliding motion when the ligating element 20 is pushed along the core 121 of the tie wing 12 to close or open the archwire slot13.

[0060] To close the archwire slot 13 with the archwire 30 inside, the operator will push the ligating element 20 pre-assembled on the base bracket 10 to cover the archwire slot 13. The operator can start pushing the ligating element 20 toward the occlusal side 43 of the base bracket 10. When the ligating ledge 25 is going over the archwire slot 13, the dovetail channel 24 in the ligating element 20 will engage the dovetail block 16 until the leading surface 23 contacts the caps 122 of the tie wings on the occlusal side 43, where the archwire slot 13 is closed and the archwire 30 retained by the ligating element 2. The interference designed between the dovetail channel 24 and the dovetail block 16 will generate a tight fit and thus a holding force to retain the position of the ligating cover. When the operator wants to change the archwire during the treatment or remove the archwire 30 at the end of the treatment, the operator can use small dental tools to push the ligating element 20 toward the gingival side 42. Once the ligating element 20 contacts the cap 122 of the tie wings 12 on the gingival side 42, the archwire slot 13 is fully open.

[0061] The commonality of the embodiments above is that the tie wings 12 can still function as for non-self-ligating bracket. When the base bracket 10 is used without the selfligating feature, to retain the archwire slot 13 with the archwire 30 inside, the operator will tie orthodontic archwire 30 using either a metal wire or a plastic loop. The operator will first engage the metal wire or plastic loop underneath one tie wing 12 on either the mesial side 41 or the distal side 40 and lay the metal wire or plastic loop within the undercut of the tie wing 12. When the metal wire or plastic loop reaches the orthodontic archwire 30, the operator will route the metal wire or plastic loop above the archwire 30 and let it crossover the archwire 30. Then the metal wire or plastic loop will be brought back underneath the second pair tie wing 12 on the same side. After the operator finishes on one side of the bracket, the operator will pull the metal wire or plastic loop to the other side of the base bracket 10, where the operator will follow the same sequence of operations to tie down the archwire 30. After the metal wireor plastic loop is made at least one loop around the base bracket 10, the operator will cut the metal wire to the right length and use a tool to twist tight the metal wire or the plastic loop itself will close the loop around the base bracket 10 after the sequence of operation is done.

[0062] The innovation of the embodiments above is that the tie wings 12 are located on the mesial side 41 and the distal sides 40 of the base bracket 10 and are used as tie wings 12 for the non-self-ligating version and guide rails for the self-ligating version. In addition, the self-ligating feature has a sliding or snapping mechanism to close and open the archwire slot 13 for the archwire 30 guided by the tie wings 12.

[0063] While particular embodiments of the present invention have been shown and described, it will be obvious to those of ordinary' skill in the art that, based upon the teachings herein, changes and modifications may be made without departing from this exemplary embodiment(s) of the present invention and its broader aspects. Therefore, the appended claims are intended to encompass within their scope all such changes and modifications as are within the true spirit and scope of this exemplary embodiment(s) of the present invention.

Claims

CLAIMSWhat is claimed is:

1. An orthodontic bracket comprising: a base bracket comprising a mesial side and a distal side, and comprising a plurality of tie wings disposed on the mesial side and the distal side of the base bracket; and, an archwire slot that extends from the mesial side to the distal side; a ligating element configured to detachably engage with the plurality of tie wings of the base bracket to selectively close the archwire slot of the base bracket.

2. The orthodontic bracket of claim 1, wherein the tie wings include undercuts or recesses configured to receive the clips.

3. The orthodontic bracket of claim 2, wherein the base bracket comprises four tie wings, the four tie wings are arranged in opposing pairs, with one pair disposed near the gingival side, and the other pair of tie wings disposed near the occlusal side.

4. The orthodontic bracket of claim 3, wherein the ligating element further comprises a base and four clips are disposed at four comers of the base.

5. The orthodontic bracket of claim 4, wherein two clips arc located on the gingival side, and two clips are located on the occlusal side.

6. The orthodontic bracket of claim 5, wherein the ligating element is formed by injection molding, metal forming, or 3D printing.

7. The orthodontic bracket of claim 6, wherein the clips are configured to snap onto the tie wings in a mesial-distal direction.

8. The orthodontic bracket of claim 1, wherein the base bracket further comprises a bonding pad positioned opposite to the tie wings and the archwire slot.

9. The orthodontic bracket of claim 3, wherein the ligating element further comprises a ligating wire having a long section, a short section, and a bent-over section; the bent-over section connects the long section and the short section, wherein the bent over section is detachable and partially overlay the tie wings on the occlusal side.

10. The orthodontic bracket of claim 9, wherein the long section is inserted beneath the tie wings on both the mesial and distal sides of the base bracket.11 . The orthodontic bracket of claim 9, wherein the short section extends over the archwire slot of the base bracket.

12. The orthodontic bracket of claim 9, wherein the ligating wire is preassembled onto the base bracket.

13. The orthodontic bracket of claim 9, wherein the ligating wire is formed from metal or polymer and shaped by bending or polymer injection molding.

14. The orthodontic bracket of claim 9, wherein the base bracket further comprises a ligating wedge disposed between the tie wings and the archwire slot, and near the occlusal side.

15. The orthodontic bracket of claim 14, wherein the ligating wedge comprises a high end, a low end, and a sloped surface located between the high end and the low end; the high end is near the archwire slot, and the low end is near the occlusal side of the base bracket.

16. The orthodontic bracket of claim 15, wherein the base bracket further comprises a stopper disposed on a gingival side of the base bracket; the stopper comprises an abutting surface configured to limit the motion of the ligating wire.

17. The orthodontic bracket of claim 16, wherein the height of the abutting surface of the stopper is greater than the height of the high end of the ligating wedge.

18. The orthodontic bracket of claim 3, wherein the base bracket further comprises a plurality of cores and a plurality of caps; each cap is integrally formed on top of the core and extends in a distal-mesial direction to form a protruding surface.

19. The orthodontic bracket of claim 18, wherein the number of the core is two, and the number of the cap is two.

20. The orthodontic bracket of claim 19, wherein one of the cores is located near the gingival side, and another core is located near the occlusal side; one of the caps is located near the gingival side, and another cap is located near the occlusal side.21 . The orthodontic bracket of claim 20, wherein the base bracket further comprises a dovetail block protruding from one of the cores and near the occlusal side.

22. The orthodontic bracket of claim 21, wherein the ligating element comprises a dovetail channel configured to engage the dovetail block.

23. The orthodontic bracket of claim 18, wherein the ligating element further comprises a leading surface configured to assist in alignment with the base bracket.

24. The orthodontic bracket of claim 18, wherein the ligating element further comprises a ligating ledge formed near the gingival site extending toward the occlusal side.

Images