CROSS-REFERENCE TO RELATED APPLICATION(S)

[00011 This application claims the benefit of priority to U.S. Provisional Patent

Application No. 63/201,929, which is incorporated by reference herein in its entirety.

[0002 j This application is related to the following applications, each of which is hereby incorporated by reference in its entirety: U.S. Patent Application No. 16/865,323, titled DENTAL APPLIANCES, SYSTEMS AND METHODS, filed May 2, 2020; International Patent Application No. PCT/US20/31211, titled DENTAL APPLIANCES, SYSTEMS AND METHODS, filed May 2, 2020; U.S. Patent Application No. 15/929,443, titled DENTAL APPLIANCES AND ASSOCIATED SYSTEMS AND METHODS OF USE, filed May 2, 2020; U.S. Patent Application No. 15/929,444, titled DENTAL APPLIANCES AND ASSOCIATED SYSTEMS AND METHODS OF USE, filed May 2, 2020; International Application No. PCT/US20/70017, titled DENTAL APPLIANCES AND ASSOCIATED SYSTEMS AND METHODS OF USE, filed May 2, 2020; U.S. Patent Application No. 15/929,442, titled DENTAL APPLIANCES AND ASSOCIATED METHODS OF MANUFACTURING, filed May 2, 2020; International Application No. PCT/US20/70016, titled DENTAL APPLIANCES AND ASSOCIATED METHODS OF MANUFACTURING, filed May 2, 2020; U.S. Provisional Patent Application No. 62/956,290, titled ORTHODONTIC APPLIANCES AND ASSOCIATED SYSTEMS AND METHODS OF USE, filed January 1, 2020; U.S. Provisional Patent Application No. 62/842,391, titled TEETH REPOSITIONING SYSTEMS AND METHODS, filed May 2, 2019; and U.S. Provisional Patent Application No. 62/704,545, titled DENTAL APPLIANCES AND ASSOCIATED SYSTEMS AND METHODS OF USE, filed May 15, 2020.

TECHNICAL FIELD

[0003] The present technology relates to orthodontic devices for treating teeth and associated systems and methods. BACKGROUND

{0004) A common objective in orthodontics is to move a patient's teeth to positions where the teeth function optimally and aesthetically. To move the teeth, the orthodontist may begin by obtaining multiple scans and/or impressions of the patient’s teeth to determine a series of corrective paths between the initial positions of the teeth and the desired ending positions. The orthodontist then fits the patient to one of two main appliance types: braces or aligners.

(0005) Traditional braces consist of brackets and an archwire placed across a front side of the teeth, with elastic ties or ligature wires to secure the archwire to the brackets. In some cases self-ligating brackets may be used in lieu of ties or wires. The shape and stiffness of the archwire as well as the archwire-bracket interaction governs the forces applied to the teeth and thus the direction and degree of tooth movement. To exert a desired force on the teeth, the orthodontist often manually bends the archwire. The orthodontist monitors the patient’s progress through regular appointments, during which the orthodontist visually assesses the progress of the treatment and makes manual adjustments to the archwire (such as new bends) and/or replaces or repositions brackets. The adjustment process is both time consuming and tedious for the patient and more often than not results in patient discomfort for several days following the appointment. Moreover, braces are not aesthetically pleasing and make brushing, flossing, and other dental hygiene procedures difficult.

[O0O6| Aligners comprise clear, removable, polymeric shells having cavities shaped to receive and reposition teeth to produce a final tooth arrangement. Aligners offer patients significantly improved aesthetics over braces. Aligners do not require the orthodontists to bend wires or reposition brackets and are generally more comfortable than braces. However, unlike braces, aligners cannot effectively treat all malocclusions. Certain tooth repositioning steps, such as extrusion, translation, and certain rotations, can be difficult or impossible to achieve with aligners. Moreover, because the aligners are removable, success of treatment is highly dependent on patient compliance, which can be unpredictable and inconsistent.

(0007) Lingual braces are an alternative to aligners and traditional (buccal) braces and have been gaining popularity in recent years. Two examples of existing lingual braces are the Incognito™ Appliance System (3M United States) and INBRACE® (Swift Health Systems, Irvine, California, USA), each of which consists of brackets and an archwire placed on the lingual, or tongue side, of the teeth. In contrast to traditional braces, lingual braces are virtually invisible, and, unlike aligners, lingual braces are fixed to the patient’s teeth and force compliance. These existing lingual technologies, however, also come with several disadvantages. Most notably, conventional lingual appliances still rely on a bracket-archwire system to move the teeth, thus requiring multiple office visits and painful adjustments. For example, lingual technologies have a relatively short inter-bracket distance, which generally makes compliance of the archwire stiffer. As a result, the overall lingual appliance is more sensitive to archwire adjustments and causes more pain for the patient. Moreover, the lingual surfaces of the appliance can irritate the tongue and impact speech, and make the appliance difficult to clean.

[0008} Therefore, a need exists for improved orthodontic appliances.

SUMMARY

[0009] Various embodiments of the present technology relate to orthodontic brackets and associated methods of manufacturing. In some embodiments, an orthodontic bracket of the present technology can be configured to bond strongly to a patient’s tooth. Such bracket can be custom shaped to a patient’s tooth and/or can include surface features that facilitate bonding of the bracket to the tooth. For example, a surface of a bracket configured to be secured to a tooth can have a greater surface roughness than a surface of the bracket configured to face away from the tooth. The increased surface roughness of the tooth-facing surface can facilitate bonding of the bracket to the tooth, while the lower surface roughness of the other surface can enhance patient comfort.

[0010] The novel manufacturing methods of the present technology can be employed to form brackets that are custom-shaped and/or have a selective surface topology. The additive manufacturing processes disclosed herein can form a bracket with an organic, non-geometric shape such that the bracket is configured to substantially conform to a patient’s tooth. In some embodiments, a bracket formed by additive manufacturing can have a high surface roughness, such that a surface of the bracket configured to be secured to the patient’s tooth is configured to strongly bond to the tooth. Additionally or alternatively, a selective smoothing process can be employed to reduce a surface roughness of certain regions of the bracket, such as the surface configured to face away from the tooth. In some embodiments, support structures that are integrally formed with the bracket during the additive manufacturing process can be used during the selective smoothing process as a mask to prevent or limit reduction of a surface roughness of certain other regions of the bracket, such as the tooth-facing surface.

[0011] The subject technology is illustrated, for example, according to various aspects described below, including with reference to FIGS. 1A-13. Various examples of aspects of the subject technology are described as numbered clauses (1, 2, 3, etc.) for convenience. These are provided as examples and do not limit the subject technology.

1. A method for making an orthodontic bracket, the method comprising: forming a build piece by an additive manufacturing process, the build piece comprising a bracket portion having a first surface and a second surface and a sacrificial portion positioned at the second surface; while the sacrificial portion is positioned at the second surface, reducing an average surface roughness of the first surface without substantially reducing an average surface roughness of the second surface; and removing the sacrificial portion from the build piece such that the average surface roughness of the second surface is greater than the average surface roughness of the first surface.

2. The method of Clause 1, wherein the additive manufacturing process comprises at least one of direct metal laser sintering, selective laser melting, fused deposition modeling, fused filament fabrication, or binder jetting.

3. The method of Clause 1 or Clause 2, wherein removing the sacrificial portion from the build piece comprises breaking the sacrificial portion.

4. The method of any one of Clauses 1 to 3, wherein removing the sacrificial portion from the build piece comprises applying tensile, compressive, shear, and or torsional stress on the sacrificial portion.

5. The method of any one of Clauses 1 to 4, wherein, after removing the sacrificial portion from the build piece, the second surface comprises one or more protrusions and/or recesses. 6 The method of any one of Clauses 1 to 5, wherein reducing the average surface roughness of the first surface comprises electropolishing the build piece.

7. The method of any one of Clauses 1 to 6, wherein reducing the average surface roughness of the first surface comprises positioning the build piece in acid.

8. The method of any one of Clauses 1 to 7, wherein the reducing the average surface roughness of the first surface comprises reducing at least one of an arithmetical mean height parameter, a maximum profile valley depth parameter, a maximum profile heigh parameter, or a mean height of profile elements parameter.

9. A method for making an orthodontic bracket, the method comprising: successively fusing particles of a material to form a build piece comprising a bracket portion and a support portion, wherein the bracket portion is integral with the support portion at an interfacial region; electropolishing the build piece such that a surface roughness of the bracket portion is reduced except at the interfacial region; and separating the support portion from the bracket portion at the interfacial region.

10. The method of Clause 9, wherein separating the support portion from the bracket portion comprises cutting the support portion with a bandsaw.

11. The method of Clause 9 or Clause 10, wherein separating the support portion from the bracket portion comprises cutting the support portion via electron discharge machining.

12. The method of any one of Clauses 9 to 11, wherein the material comprises a metal and/or a metal alloy.

13. The method of Clause 12, wherein the material comprises stainless steel. 14. The method of any one of Clauses 9 to 13, wherein the material comprises a powder.

15. The method of any one of Clauses 9 to 14, wherein the material comprises a filament.

16. The method of any one of Clauses 9 to 15, wherein successively fusing the particles comprises at least one of delivering thermal energy to the particles, delivering a binding agent to the particles, or compressing the particles.

17. The method of any one of Clauses 9 to 16, wherein successively fusing the particles comprises: fusing a first layer of the particles; and fusing a second layer of the particles on the first layer.

18. The method of any one of Clauses 9 to 17, wherein electropolishing the build piece comprises dry electropolishing.

19. A device for securing an attachment portion of an orthodontic appliance to a tooth of a patient, the device comprising: a body portion including a first surface and a second surface opposite the first surface along a thickness of the body portion, wherein the second surface is configured to be secured to a surface of the patient’s tooth and substantially conforms to the surface of the patient’s tooth; and a securing portion positioned at the first surface of the body portion, the securing portion comprising at least two arms configured to prevent or limit translation and/or rotation of the attachment portion of the appliance relative to the device, wherein each of the at least two arms is movable between an open configuration in which the attachment portion of the appliance is movable relative to the device and a closed configuration in which the attachment portion is secured relative to the device. 20. The device of Clause 19, wherein the first surface has a first average surface roughness and the second surface has a second average surface roughness, the second average surface roughness being greater than the first average surface roughness.

21. The device of Clause 19 or Clause 20, wherein the device comprises a plurality of layers of fused particles.

22. The device of any one of Clauses 19 to 21, wherein the device comprises a metal or a metal alloy.

23. The device of any one of Clauses 19 to 22, wherein the second surface defines one or more recesses extending therein.

24. The device of any one of Clauses 19 to 23, wherein the second surface comprises one or more protrusions.

25. The device of Clause 24, wherein the one or more protrusions comprise residual material from an additive manufacturing process.

26. The device of any one of Clauses 19 to 25, wherein the second surface has an area corresponding to between about 50% to about 100% of an area of the surface of the patient’s tooth to which the second surface is configured to be secured.

27. The device of any one of Clauses 19 to 26, wherein the securing portion comprises a substantially flat engagement region positioned at the first surface of the body portion.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Instead, emphasis is placed on illustrating clearly the principles of the present disclosure.

[0013] FIGS. 1A and IB schematically illustrate directional references relative to a patient’s dentition.

{0014) FIG. 2A shows the schematic representation of an orthodontic appliance configured in accordance with the present technology installed in a patient’s mouth adjacent the patient’s dentition.

[0015] FIG. 2B is a schematic depiction of connection configuration options configured in accordance with embodiments of the present technology.

{0016) FIG. 2C is a schematic depiction of a portion of an appliance configured in accordance with embodiments of the present technology.

{0017] FIG. 2D is a schematic depiction of a portion of an appliance configured in accordance with embodiments of the present technology.

[0018] FIG. 2E is a schematic depiction of a portion of an appliance configured in accordance with embodiments of the present technology.

[0019] FIGS. 3 A and 3B are elevation views of an appliance configured in accordance with several embodiments of the present technology installed in an upper and lower jaw of a patient’s mouth with the patient’s teeth in an original tooth arrangement and a final tooth arrangement, respectively.

[0020] FIG. 3C depicts example stress-strain curves of nitinol and steel.

[0021] FIGS. 4A and 4B illustrate an orthodontic bracket in accordance with several embodiments of the present technology.

[0022) FIG. 5 illustrates an orthodontic appliance installed within a patient’s mouth in accordance with several embodiments of the present technology.

[0023] FIG. 6 is a flow diagram of a process for obtaining a digital model of an orthodontic bracket in accordance with several embodiments of the present technology.

[0024] FIG. 7 is a flow diagram of a process for manufacturing an orthodontic bracket in accordance with several embodiments of the present technology.

[0025] FIG. 8 illustrates a build piece comprising a bracket portion and a support portion in accordance with several embodiments of the present technology. (0026) FIG. 9 illustrates a build piece in accordance with several embodiments of the present technology.

(0027) FIG. 10A is a fragmentary sagittal view of a patient’s mouth with orthodontic brackets of the present technology secured to the patient’s teeth.

[0028] FIG. 10B is a front view of the orthodontic brackets of FIG. 10A.

[0029] FIGS. 11 A and 1 IB are side and front views, respectively, of an orthodontic bracket in accordance with several embodiments of the present technology.

(0030) FIGS. 12A and 12B are side and front views, respectively, of an orthodontic bracket in accordance with several embodiments of the present technology.

[0031] FIG. 13 is a front view of a patient’ s tooth with an orthodontic bracket of the present technology secured to the tooth.

DETAILED DESCRIPTION

[0032] The present technology relates to devices for treating teeth and associated systems and methods. Various embodiments of the present technology, for example, are directed to orthodontic brackets and associated methods of manufacturing. In some embodiments, a bracket can be custom-shaped such that the bracket has a shape substantially corresponding to a shape of a patient’s tooth. Such custom brackets can bond more strongly to the patient’s teeth than off-the- shelf brackets and are more durable and comfortable. Additionally or alternatively, a bracket according to several embodiments of the present technology can have surface features configured to enhance bonding of the bracket to a patient’s tooth. For example, a surface of the bracket configured to be secured to the tooth can have a large surface roughness, and thereby a large surface area, to facilitate bonding of the bracket to the tooth.

[0033 ] A custom bracket of the present technology may have an organic, complex, and/or non-geometrical shape, which can be challenging and/or costly to form by conventional subtractive manufacturing techniques. Thus, a method of manufacturing an orthodontic bracket can comprise forming the bracket by an additive manufacturing process in which particles of a material are fused in successive layers. While additive manufacturing can produce brackets with complex designs that would otherwise be challenging and costly to produce, the surface properties of such brackets produced by additive manufacturing can be challenging to control. A surface of the bracket is discretized into layers of finite height during the additive manufacturing process, which can produce offsets between adjacent layers that increase a surface roughness of the bracket. Additionally, as brackets made by additive manufacturing are formed layer-by-layer, each new layer must be supported by a previous layer. Accordingly, it may be necessary to form auxiliary support structures with the bracket so that the bracket is sufficiently supported during the additive manufacturing process. While such support structures can be removed after the bracket is formed, surfaces of the bracket to which the support structures were coupled often have a large surface roughness.

[0034] As previously noted, it may be beneficial for certain regions of an orthodontic bracket to be smooth. Accordingly, in some embodiments a method of manufacturing a bracket can include reducing a surface roughness of the bracket. For example, the method can include electropolishing the bracket. However, as previously noted, it may be beneficial for certain regions of an orthodontic bracket to have a large surface roughness to facilitate bonding of the bracket to a patient’s tooth. Accordingly, in some embodiments a method of the present technology includes selectively reducing a surface roughness of the bracket such that at least one portion of the bracket has a higher surface roughness than other portions of the bracket. In such embodiments, a mask can be positioned at the regions of the bracket intended to have a large surface roughness such that, during a smoothing process, the surface roughness of the masked regions is not substantially reduced. As will be described in greater detail herein, in some embodiments support structures can serve as the mask to limit potentially costly and/or time consuming additional steps.

I. Definitions

[0035] FIGS. 1A and IB schematically depict several directional terms related to a patient’s dentition. Terms used herein to provide anatomical direction or orientation are intended to encompass different orientations of the appliance as installed in the patient’s mouth, regardless of whether the structure being described is shown installed in a mouth in the drawings. As illustrated in FIGS. 1A and IB: “mesial” means in a direction toward the midline of the patient’s face along the patient's curved dental arch; “distal” means in a direction away from the midline of the patient’s face along the patient's curved dental arch; “occlusal” means in a direction toward the chewing surfaces of the patient’s teeth; “gingival” means in a direction toward the patient's gums or gingiva; “facial” means in a direction toward the patient's lips or cheeks (used interchangeably herein with “buccal” and “labial”); and “lingual” means in a direction toward the patient's tongue.

[0036] As used herein, the terms "proximal" and "far" refer to a position that is closer and farther, respectively, from a given reference point. In many cases, the reference point is a certain connector, such as an anchor, and "proximal" and "far" refer to a position that is closer and farther, respectively, from the reference connector along a line passing through the centroid of the cross- section of the portion of the appliance branching from the reference connector.

[0037] As used herein, the terms “generally,” "substantially," "about," and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent variations in measured or calculated values that would be recognized by those of ordinary skill in the art.

[0038] As used herein, the term “operator” refers to a clinician, practitioner, technician or any person or machine that designs and/or manufactures an orthodontic appliance or portion thereof, and/or facilitates the design and/or manufacture of the appliance or portion thereof, and/or any person or machine associated with installing the appliance in the patient’s mouth and/or any subsequent treatment of the patient associated with the appliance.

[0039] As used herein, the term “force” refers to the magnitude and/or direction of a force, a torque, or a combination thereof.

[0040] As used herein, the terms “digital model” and “model” are intended to refer to a virtual representation of an object or collection of objects. For example, the term “bracket digital model” refers to the virtual representation of the structure and geometry of the bracket, including its individual components (e.g., the body portion, the securing portion, etc.).

II. Overview of Orthodontic Appliances of the Present Technology

[0041] FIG. 2A is a schematic representation of an orthodontic appliance 100 (or

“appliance 100”) configured in accordance with embodiments of the present technology, shown positioned in a patient’ s mouth adj acent the patient’ s teeth. FIG. 2B is an enlarged view of a portion of the appliance 100 The appliance 100 is configured to be installed within a patient’s mouth to impart forces on one or more of the teeth to reposition all or some of the teeth. In some cases, the appliance 100 may additionally or alternatively be configured to maintain a position of one or more teeth. As shown schematically in FIGS. 2A and 2B, the appliance 100 can comprise a deformable member that includes one or more attachment portions 140 (each represented schematically by a box), each configured to be secured to a tooth surface directly or indirectly via a securing member 160. The appliance 100 may further comprise one or more connectors 102 (also depicted schematically), each extending directly between attachment portions 140 (“first connectors 104”), between an attachment portion 140 and one or more other connectors 102 (“second connectors 106”), or between two or more other connectors 102 (“third connectors 108”). Only two attachment portions 140 and two connectors 102 are labeled in FIG. 2 A for ease of illustration. As discussed herein, the number, configuration, and location of the connectors 102 and attachment portions 140 may be selected to provide a desired force on one or more of the teeth when the appliance 100 is installed.

[0042] The attachment portions 140 may be configured to be detachably coupled to a securing member 160 that is bonded, adhered, or otherwise secured to a surface of one of the teeth to be moved. In some embodiments, one or more of the attachment portions 140 may be directly bonded, adhered, or otherwise secured to a corresponding tooth without a securing member or other connection interface at the tooth. The attachment portions 140 may also be referred to as “bracket connectors” or “male connector elements” herein. The different attachment portions 140 of a given appliance 100 may have the same or different shape, same or different size, and/or same or different configuration. The attachment portions 140 may comprise any of the attachment portions, bracket connectors, and/or male connector elements disclosed in U.S. Patent Application No. 15/370,704 (Publ. No. 2017/0156823) filed December 6, 2016, U.S. Patent Application No. 15/929,443 (Publ. No. 2021/0007830) filed May 2, 2020, and U.S. Patent Application No. 15/929,444 (Publ. No. 2020/0390524) filed May 2, 2020, which are incorporated by reference herein in their entirety. The securing members 160 can comprise an orthodontic bracket such as, but not limited to, any of the brackets disclosed herein. Additionally or alternatively, the securing members 160 may comprise any of the securing members and/or brackets disclosed in U.S. Patent Application Nos. 15/370,704, 15/929,443, and 15/929,444.

[0043] The appliance 100 may include any number of attachment portions 140 suitable for securely attaching the appliance 100 to the patient’s tooth or teeth in order to achieve a desired movement. In some examples, multiple attachment portions 140 may be attached to a single tooth. The appliance 100 may include an attachment portion for every tooth, fewer attachment portions than teeth, or more attachment portions 140 than teeth. In these and other embodiments, the appliance 100 one or more of the attachment portions 140 may be configured to be coupled to one, two, three, four, five or more connectors 102. Moreover, any of the first and second connectors 104, 106 can extend from any portion of a corresponding attachment portion 140. For example, one or both ends of a given first and/or second connector 104, 106 can be disposed at an occlusal, gingival, mesial, or distal side of a corresponding attachment portion 140. In some embodiments, a location at which a connector connects to an attachment portion is based at least in part on an amount of space in the patient’s mouth, an intended force to be applied to a tooth, etc. For example, in some cases it may be challenging to connect a second connector 106 to a gingival portion of an attachment portion 140 that is configured to impart an intended torque on a tooth to which the attachment portion 140 is configured to be secured. Accordingly, it may be preferable for the second connector 106 to connect to a mesial portion or a distal portion of the attachment portion 140 in these embodiments and others. In some cases, it may be challenging to connect a first and/or second connector 104, 106 to a mesial or distal portion of an attachment portion 140 due to the space within a patient’s mouth. For example, if connecting the connector to a mesial or distal portion of an attachment portion 140 would cause the connector to collide with an adjacent tooth during installation or treatment, it may be preferable to connect the connector to a gingival or an occlusal portion of the attachment portion 140 to prevent such collision.

{0044 j As previously mentioned, the connectors 102 may comprise one or more first connectors 104 that extend directly between attachment portions 140. The one or more first connectors 104 may extend along a generally mesiodistal dimension when the appliance 100 is installed in the patient’s mouth. In these and other embodiments, the appliance 100 may include one or more first connectors 104 that extend along a generally occlusogingival and/or buccolingual dimension when the appliance 100 is installed in the patient’s mouth. According to several embodiments, a single first connector 104 can have one or more bends such that it extends at least two of mesiodistally, occlusogingivally, or buccolingually. FIG. 2D, for example, shows a first connector 104a that extends gingivally from a gingival side of a first attachment portion 140a then bends and extends occlusally until terminating at a gingival side of a second attachment portion 140b. First connector 104b extends distally (assuming a midline M) from a distal side of the second attachment portion 140b, then bends and extends gingivally, then bends and extends occlusally, then bends and extends distally until terminating at a mesial side of a third attachment portion 140c. First connector 104c extends distally from a distal side of the third attachment portion 140c to a mesial side of a fourth attachment portion 140d. It will be appreciated that many other first connector geometries are possible and that showing every possible first connector shape would not be feasible. In some embodiments, the appliance 100 does not include any first connectors 104.

[0045] In several embodiments, all of the attachment portions 140 of the appliance 100 are coupled to one another only by first connectors 104 (and no second or third connectors 106, 108) (also referred to as a “Z appliance” herein). FIG. 2D, for example, shows a portion of such a Z appliance 100. In these embodiments, some or all of the first connectors 104 can have the same geometry. In some of the Z appliances 100, some or all of the first connectors 104 can have a different geometry. For the sake of explanation, the portion of the appliance 100 shown in FIG. 2D includes a different first connector geometry between each pair of adjacent teeth T. While not labeled in FIG. 2D, one, some, or all of the first connectors 104 in a Z appliance 100 can have one or more biasing portions (described in greater detail below). One, some, or all of the first connectors 104 in a Z appliance 100 can be rigid. It may be advantageous for an appliance 100 to comprise only first connectors 104 if a patient has tori that would obstruct more gingivally positioned second or third connectors 106, 108, if space in a patient’s mouth is limited, etc.

[0046] Additionally or alternatively, the connectors 102 may comprise one or more second connectors 106 that extend between one or more attachment portions 140 and one or more connectors 102. The one or more second connectors 106 can extend along a generally occlusogingival dimension when the appliance 100 is installed in the patient’s mouth. In these and other embodiments, the appliance 100 may include one or more second connectors 106 that extend along a generally mesiodistal and/or buccolingual dimension when the appliance 100 is installed in the patient’s mouth. In some embodiments, the appliance 100 does not include any second connectors 106. In such embodiments, the appliance 100 would only include first connectors 104 extending between attachment portions 140. In some embodiments, multiple second connectors 106 may extend from the same location along the appliance 100 to the same attachment portion 140. The use of two or more connectors to connect two points on the appliance 100 enables application of a greater force (relative to a single connector connecting the same points) without increasing the strain on the individual connectors. Such a configuration is especially beneficial given the spatial constraints of the fixed displacement treatments herein. (0047) Additionally or alternatively, the connectors 102 may comprise one or more third connectors 108 that extend between two or more other connectors 102. The one or more third connectors 108 may extend along a generally mesiodistal dimension when the appliance 100 is installed in the patient’s mouth. In these and other embodiments, the appliance 100 may include one or more third connectors 108 that extend along a generally occlusogingival and/or buccolingual dimension when the appliance 100 is installed in the patient’s mouth. In some embodiments, the appliance 100 does not include any third connectors 108. One, some, or all of the third connectors 108 may be positioned gingival to one, some, or all of the first connectors 104. In some embodiments, the appliance 100 includes a single third connector 108 that extends along at least two adjacent teeth and provides a common attachment for two or more second connectors 106. In several embodiments, the appliance 100 includes multiple non-contiguous third connectors 108, each extending along at least two adjacent teeth.

[00481 In several embodiments, all of the attachment portions 140 of the appliance 100 are coupled to one another only by second and third connectors 106, 108 (and no first connectors 104) (also referred to as an “X appliance” herein). FIG. 2A, for example, shows such an X appliance 100. In these embodiments, and others, some or all of the second connectors 106 can have the same geometry. In some of the X appliances 100, some or all of the second connectors 106 can have a different geometry. While not labeled in FIG. 2A, one, some, or all of the second connectors 106 in an X appliance 100 can have one or more biasing portions. One, some, or all of the second connectors 106 in an X appliance 100 can be rigid.

(0049) In several embodiments, the appliance 100 comprises two or more attachment portions 140 that are coupled to one another by first connectors 104 and two or more attachment portions 140 coupled to one another by second and third connectors 106, 108. In some embodiments, the appliance 100 comprises two or more attachment portions 140 that are coupled to one another by first connectors 104 (and no second or third connectors 106, 108) and two or more attachment portions 140 coupled to one another by second and third connectors 106, 108 (and no first connectors 104). The foregoing hybrid appliances are referred to herein as “XZ appliances.” FIG. 2E, for example, shows a portion of such an XZ appliance 100. In these embodiments, and others, some or all of the first connectors 104 can have the same geometry. In some of the XZ appliances 100, some or all of the first connectors 104 can have a different geometry. While not labeled in FIG. 2E, one, some, or all of the first connectors 104 in an XZ appliance 100 can have one or more biasing portions. One, some, or all of the first connectors 104 in an XZ appliance 100 can be rigid. In an XZ appliance 100, some or all of the second connectors 106 can have the same geometry. In some of the XZ appliances 100, some or all of the second connectors 106 can have a different geometry. While not labeled in FIG. 2E, one, some, or all of the second connectors 106 in an XZ appliance 100 can have one or more biasing portions. One, some, or all of the second connectors 106 in an XZ appliance 100 can be rigid. Although FIG. 2E depicts the third connector 108 mesiodistally adjacent to the first connectors 104, in some XZ appliances 100 one or more first connectors 104 can be mesiodistally aligned with one or more third connectors 108.

[0050} As shown in FIG. 2 A, in some embodiments the appliance 100 may be configured such that all or a portion of one, some, or all of the connectors 102 are disposed proximate the patient’s gingiva when the appliance 100 is installed within the patient’s mouth. For example, one or more third connectors 108 may be configured such that all or a portion of the one or more third connectors 108 is positioned below the patient’s gum line and adjacent to but spaced apart from the gingiva. In many cases it may be beneficial to provide a small gap (e.g., 0.5 mm or less) between the third connector(s) 108 and the patient’s gingiva, as contact between the third connector(s) 108 (or any portion of the appliance 100) and the gingiva can cause irritation and patient discomfort. In some embodiments, all or a portion of the third connector(s) 108 is configured to be in direct contact with the gingiva when the appliance 100 is disposed in the patient’s mouth. Additionally or alternatively, all or a portion of one or more first connectors 104 and/or second connectors 106 may be configured to be disposed proximate the gingiva.

[0051] According to some embodiments, one or more connectors 102 may extend between an attachment portion 140 or connector 102 and a joint comprising (a) two or more connectors 102, (b) two or more attachment portions 140, or (c) at least one attachment portion 140 and at least one connector 102. According to some embodiments, one or more connectors 102 may extend between a first joint comprising (a) two or more connectors 102, (b) two or more attachment portions 140, or (c) at least one attachment member and at least one connector 102, and a second joint comprising (a) two or more connectors 102, (b) two or more attachment portions 140, or (c) at least one attachment portion 140 and at least one connector 102. An example of a connector 102 extending between (a) a joint between a second and third connector 106, 108, and (b) a joint between a second connector 106 and an attachment portion 140 is depicted schematically and labeled 109 in FIG. 2B.

[0052] Each of the connectors 102 may be designed to have a desired stiffness so that an individual connector 102 or combination of connectors 102 imparts a desired force on one or more of the teeth. In many cases, the force applied by a given connector 102 may be governed by Hooke’s Law, or F = k x x , where F is the restoring force exerted by the connector 102, k is the stiffness coefficient of the connector 102, and x is the displacement. In the most basic example, if a connector 102 does not exist between two points on the appliance 100, then the stiffness coefficient along that path is zero and no forces are applied. In the present case, the individual connectors 102 of the present technology may have varying non-zero stiffness coefficients. For example, one or more of the connectors 102 may be rigid (i.e., the stiffness coefficient is infinite) such that the connector 102 will not flex or bend between its two end points. In some embodiments, one or more of the connectors 102 may be “flexible” (i.e., the stiffness coefficient is non-zero and positive) such that the connector 102 can deform to impart (or absorb) a force on the associated tooth or teeth or other connector 102.

[0053} In some embodiments it may be beneficial to include one or more rigid connectors between two or more teeth. A rigid connector 102 is sometimes referred to herein as a “rigid bar” or an “anchor.” Each rigid connector 102 may have sufficient rigidity to hold and maintain its shape and resist bending. The rigidity of the connector 102 can be achieved by selecting a particular shape, width, length, thickness, and/or material. Connectors 102 configured to be relatively rigid may be employed, for example, when the tooth to be connected to the connector 102 or arm is not to be moved (or moved by a limited amount) and can be used for anchorage. Molar teeth, for example, can provide good anchorage as molar teeth have larger roots than most teeth and thus require greater forces to be moved. Moreover, anchoring one or more portions of the appliance 100 to multiple teeth is more secure than anchoring to a single tooth. As another example, a rigid connection may be desired when moving a group of teeth relative to one or more other teeth. Consider, for instance, a case in which the patient has five teeth separated from a single tooth by a gap, and the treatment plan is to close the gap. The best course of treatment is typically to move the one tooth towards the five teeth, and not vice versa. In this case, it may be beneficial to provide one or more rigid connectors between the five teeth. For all of the foregoing reasons and many others, the appliance 100 may include one or more rigid first connectors 104, one or more rigid second connectors 106, and/or one or more rigid third connectors 108.

[0054] In these and other embodiments, the appliance 100 may include one or more flexible first connectors 104, one or more flexible second connectors 106, and/or one or more flexible third connectors 108. Each flexible connector 102 may have a particular shape, width, thickness, length, material, and/or other parameters to provide a desired degree of flexibility. According to some embodiments of the present technology, the stiffness of a given connector 102 may be tuned via incorporation of a one or more resiliently flexible biasing portions 150. As shown schematically in FIG. 2B, one, some, or all of the connectors 102 may include one or more biasing portion 150, such as springs, each configured to apply a customized force specific to the tooth to which it is attached.

[0055] As depicted in the schematic shown in FIG. 2C, the biasing portion(s) 150 may extend along all or a portion of the longitudinal axis LI of the respective connector 102 (only the longitudinal axis LI for second connector 106 and the longitudinal axis L2 for third connector 108 is labeled in FIG. 2C). The direction and magnitude of the force and torque applied on a tooth by a biasing portion 150 depends, at least in part, on the shape, width, thickness, length, material, shape set conditions, and other parameters of the biasing portion 150. As such, one or more aspects of the biasing portion 150 (including the aforementioned parameters) may be varied so that the corresponding connector 102 and/or biasing portion 150 produces a desired tooth movement when the appliance 100 is installed in the patient’s mouth. Each connector 102 and/or biasing portion 150 may be designed to move one or more teeth in one, two, or all three translational directions (i.e., mesiodistal, buccolingual, and occlusogingival) and/or in one, two, or all three rotational directions (i.e., buccolingual root torque, mesiodistal angulation and mesial out-in rotation).

[0056] The biasing portions 150 of the present technology can have any length, width, shape, and/or size sufficient to move the respective tooth towards a desired position. In some embodiments, one, some, or all of the connectors 102 may have one or more inflection points along a respective biasing portion 150. The connectors 102 and/or biasing portions 150 may have a serpentine configuration such that the connector 102 and/or biasing portion 150 doubles back on itself at least one or more times before extending towards the attachment portion 140. For example, in some embodiments the second connectors 106 double back on themselves two times along the biasing portion 150, thereby forming first and second concave regions facing in generally different directions relative to one another (as an example, see FIG. 13B). The open loops or overlapping portions of the connector 102 corresponding to the biasing portion 150 may be disposed on either side of a plane P (FIG. 2C) bisecting an overall width W (FIG. 2C) of the connector 102 such that the extra length of the connector 102 is accommodated by the space medial and/or distal to the connector 102. This allows the connector 102 to have a longer length (as compared to a linear arm) to accommodate greater tooth movement, despite the limited space in the occlusal-gingival or vertical dimension between any associated third connector 108 and the location at which the second connector 106 attaches to the tooth.

[0057} It will be appreciated that the biasing portion 150 may have other shapes or configurations. For example, in some embodiments the connector 102 and/or biasing portion 150 may include one or more linear regions that zig-zag towards the attachment portion 140. One, some, or all of the connectors 102 and/or biasing portions 150 may have only linear segments or regions, or may have a combination of curved and linear regions. In some embodiments, one, some, or all of the connectors 102 and/or biasing portions 150 do not include any curved portions.

[0058] According to some examples, a single connector 102 may have multiple biasing portions 150 in series along the longitudinal axis of the respective connector 102. In some embodiments, multiple connectors 102 may extend between two points along the same or different paths. In such embodiments, the different connectors 102 may have the same stiffness or different stiffnesses.

[0059] In those embodiments where the appliance 100 has two or more connectors 102 with biasing portions 150, some, none, or all of the connectors 102 may have the same or different lengths, the same or different widths, the same or different thicknesses, the same or different shapes, and/or may be made of the same or different materials, amongst other properties. In some embodiments, less than all of the connectors 102 have biasing portions 150. Connectors 102 without biasing portions 150 may, for example, comprise one or more rigid connections between a rigid third connector 108 and the attachment portion 140. In some embodiments, none of the connectors 102 of the appliance 100 have a biasing portion 150.

[0060] According to some embodiments, for example as depicted schematically in

FIG. 2A, the appliance 100 may include a single, continuous, substantially rigid third connector (referred to as “anchor 120”) and a plurality of flexible second connectors 106 extending away from the anchor 120. When the appliance 100 is installed in the patient’s mouth, each of the second connectors 106 may connect to a different one of the teeth to be moved and exerts a specific force on its respective tooth, thereby allowing an operator to move each tooth independently. Such a configuration provides a notable improvement over traditional braces in which all of the teeth are connected by a single archwire, such that movement of one tooth can cause unintentional movement of one or more nearby teeth. The independent and customized tooth movement enabled by the appliances of the present technology allows the operator to move the teeth from an original tooth arrangement (“OTA”) to a final tooth arrangement (“FT A”) more efficiently, thereby obviating periodic adjustments, reducing the number of office visits, and reducing or eliminating patient discomfort, and reducing the overall treatment time (i.e., the length of time the appliance is installed in the patient’s mouth) by at least 50% relative to the overall treatment time for traditional braces.

[00611 The anchor 120 may comprise any structure of any shape and size configured to comfortably fit within the patient’s mouth and provide a common support for one or more of the second connectors 106. In many embodiments, the anchor 120 is disposed proximate the patient’s gingiva when the appliance 100 is installed within the patient’s mouth, for example as shown in FIG. 2B. For instance, the appliance may be designed such that, when installed in the patient’s mouth, all or a portion of the anchor 120 is positioned below the patient’s gum line and adjacent but spaced apart from the gingiva. In many cases it may be beneficial to provide a small gap (e.g., 0.5 mm or less) between the anchor 120 (or any portion of the appliance 100) and the patient’s gingiva as contact between the anchor 120 and the gingiva can cause irritation and patient discomfort. In some embodiments, all or a portion of the anchor 120 is configured to be in contact with the gingiva when the appliance 100 is disposed in the patient’s mouth.

[0062] The anchor 120 may be significantly more rigid than the second connectors 106 such that the equal and opposite forces experienced by each of the second connectors 106 when exerting a force on its respective tooth are countered by the rigidity of the anchor 120 and the forces applied by the other second connectors 106, and do not meaningfully affect the forces on other teeth. As such, the anchor 120 effectively isolates the forces experienced by each second connectors 106 from the rest of the second connectors 106, thereby enabling independent tooth movement. (0063) According to some embodiments, for example as shown schematically in FIG. 2A and 2B, the anchor 120 comprises an elongated member having a longitudinal axis L2 (see FIG. 2C) and forming an arched shape configured to extend along a patient’s jaw when the appliance 100 is installed. In these and other embodiments, the anchor 120 may be shaped and sized to span two or more of the patient’s teeth when positioned in the patient’s mouth. In some examples, the anchor 120 includes a rigid, linear bar, or may comprise a structure having both linear and curved segments. In these and other embodiments, the anchor 120 may extend laterally across all or a portion of the patient’s mouth (e.g., across all or a portion of the palate, across all or a portion of the lower jaw, etc.) and/or in a generally anterior-posterior direction. Moreover, the appliance 100 may comprise a single anchor or multiple anchors. For example, the appliance 100 may comprise multiple, discrete, spaced apart anchors, each having two or more second connectors 106 extending therefrom. In these and other embodiments, the appliance 100 may include one or more other connectors extending between adjacent second connectors 106. In various embodiments, the anchor 120 (or any of the connectors 102 disclosed herein) can define an opening configured to receive a temporary anchorage device or other orthodontic device therein. Additionally or alternatively, the anchor 120 (or any of the connectors 102 disclosed herein) can include a securing element such as a hook, a button, a clip, etc. for securing an orthodontic device (e.g., an elastic, a temporary anchorage device, etc.) to the appliance 100.

(0064) Any and all of the features discussed above with respect to anchor 120 applies to any of the third connectors 108 disclosed herein.

(0065) As shown in FIG. 2C, each of the second connectors 106 may extend between a first end portion 106a and a second end portion 106b, and may have a longitudinal axis LI extending between the first end portion 106a and the second end portion 106b. The first end portion 106a of one, some, or all of the second connectors 106 may be disposed at the third connector 108 and/or anchor 120. In some embodiments, one, some, or all of the second connectors 106 are integral with the third connector 108 and/or anchor 120 such that the first end portion 106a of such connectors are continuous with the third connector 108 and/or anchor 120. The second connectors 106 may extend from the third connector 108 and/or anchor 120 at spaced intervals along the longitudinal axis L2 of the third connector 108 and/or anchor 120, as shown in FIGS. 2A and 2C. In some embodiments, the second connectors 106 may be spaced at even intervals relative to each other, or at uneven intervals relative to each other, along the longitudinal axis L2 of the third connector 108 and/or anchor 120.

{0066) One, some, or all of the second connectors 106 may include an attachment portion

140 at or near the second end portion 106b of the respective second connector 106. In some embodiments, for example as shown in FIGS. 2A-2C, one or more of the second connectors 106 is cantilevered from the third connector 108 and/or anchor 120 such that the second end portion 106b of the cantilevered second connector(s) 106 is free. In these and other embodiments, a gingival terminus of the attachment portion 140 may coincide with an occlusal terminus of the second connector 106. In some embodiments, the second connector 106 can connect to a mesial portion, a distal portion, and/or an occlusal portion of the attachment portion 140. The attachment portion 140 may be configured to detachably couple the respective second connector 106 to a securing member (e.g., a bracket) that is bonded, adhered, or otherwise secured to a surface of one of the teeth to be moved. In some embodiments, the attachment portion 140 may be directly bonded, adhered, or otherwise secured to a corresponding tooth without a securing member or other connection interface at the tooth. For example, the attachment portion 140 can comprise and/or can be secured to a polymeric cap having an inner surface with a contour substantially conforming to a surface of a tooth of the patient.

[0067] The appliances of the present technology may include any number of connectors 102 suitable for repositioning the patient’s teeth while taking into account the patient’s comfort. Unless explicitly limited to a certain number of connectors 102 in the specification, the appliances of the present technology may comprise a single connector 102, two connectors 102, three connectors 102, five connectors 102, ten connectors 102, sixteen connectors 102, etc. In some examples, one, some, or all of the connectors 102 of the appliance may be configured to individually connect to more than one tooth (i.e., a single connector 102 may be configured to couple to two teeth at the same time). In these and other embodiments, the appliance 100 may include two or more connectors 102 configured to connect to the same tooth at the same time.

{0068) Any portion of the appliances of the present technology may include a biasing portion 150. For example, in some embodiments, portions thereof (e.g., the anchor(s), the connector(s), the biasing portion(s), the attachment portion(s), the link(s), etc.) may comprise one or more superelastic materials. (0069) Additional details related to the individual directional force(s) applied via the biasing portion 150 or, more generally the connectors 102, are described in U.S. Application No. 15/370,704, now U.S. Patent No. 10,383,707, issued August 20, 2019, the disclosure of which is incorporated by reference herein in its entirety.

(0070) The appliances disclosed herein and/or any portion thereof (e.g., the anchor(s), the arm(s), the biasing portion(s), the attachment portion(s), the link(s), etc.) may comprise one or more superelastic materials. The appliances disclosed herein and/or any portion thereof (e.g., the anchor(s), the arm(s), the biasing portion(s), the attachment portion(s), the link(s), etc.) may comprise Nitinol, stainless steel, beta-titanium, cobalt chrome, MP35N, 35N LT, one or more metal alloys, one or more polymers, one or more ceramics, and/or combinations thereof.

(0071) The present technology includes a system comprising multiple appliances 100 for installation along a single arch. For example, the system can comprise a first appliance configured to be secured to at least two of the teeth of the arch and a second appliance configured to be secured to at least two different teeth of the same arch. The system can also comprise a third appliance, a fourth appliance, etc. The first appliance can be an X appliance, a Z appliance, or an XZ appliance. The second appliance can be an X appliance, a Z appliance, or an XZ appliance.

(0072) FIGS. 3A and 3B are elevation views of the appliance 100 installed on both the upper and lower arches of a patient’s mouth with the connectors 102 coupled to securing members 160 attached to the lingual surfaces of the teeth. It will be appreciated that the appliance 100 of one or both of the upper and lower arches may be positioned proximate a buccal side of a patient's teeth, and that the securing members 160 and/or attachment portions 140 may alternatively be coupled to the buccal surface of the teeth.

)O073] FIG. 3 A shows the teeth in an OTA with the connectors 102 in a deformed or loaded state, and FIG. 3B shows the teeth in the FTA with the connectors 102 in a substantially unloaded state. When the connectors 102 are initially secured to the securing members 160 when the teeth are in the OTA, the connectors 102 are forced to take a shape or path different than their “as designed” configurations. Because of the inherent memory of the resilient biasing portions 150, the connectors 102 impart a continuous, corrective force on the teeth to move the teeth towards the FTA, which is where the biasing portions 150 are in their as-designed or unloaded configurations. As such, tooth repositioning using the appliances of the present technology can be accomplished in a single step, using a single appliance. In addition to enabling fewer office visits and a shorter treatment time, the appliances of the present technology greatly reduce or eliminate the pain experienced by the patient as the result of the teeth moving as compared to braces. With traditional braces, every time the orthodontist makes an adjustment (such as installing a new archwire, bending the existing archwire, repositioning a bracket, etc.), the affected teeth experience a high force which is very painful for the patient. Over time, the applied force weakens until eventually a new wire is required. The appliances of the present technology, however, apply a movement-generating force on the teeth continuously while the appliance is installed, which allows the teeth to move at a slower rate that is much less painful (if painful at all) for the patient. Even though the appliances disclosed herein apply a lower and less painful force to the teeth, because the forces being applied are continuous and the teeth can move independently (and thus more efficiently), the appliances of the present technology arrive at the FTA faster than traditional braces or aligners, as both alternatives require intermediate adjustments.

[0074] In many embodiments, the movement-generating force is lower than that applied by traditional braces. In those embodiments in which the appliance comprises a superelastic material (such as nitinol), the superelastic material behaves like a constant force spring for certain ranges of strain, and thus the force applied does not drop appreciably as the tooth moves. For example, as shown in the stress-strain curves of nitinol and steel in FIG. 3C, the curve for nitinol is relatively flat compared to that of steel. Thus, the superelastic connectors and/or biasing portions of the present technology apply essentially the same stress for many different levels of strain (e.g., deflection). As a result, the force applied to a given tooth stays constant as the teeth move during treatment, at least up until the teeth are very close or in the final arrangement. The appliances of the present technology are configured to apply specific forces to a patient’s teeth that move the teeth efficiently (e.g., quickly) but without causing adverse effects such as root resorption, pain, etc. For example, the appliances of the present technology can be configured to apply a force just below the pain threshold, such that the appliance applies the maximum non-painful force to the tooth (or teeth) at all or at least most times during tooth movement. This results in the most efficient (i.e., fastest) tooth movement without pain.

[0075] In some embodiments, tooth repositioning may involve multiple steps performed progressively, by using multiple appliances. Embodiments involving multiple steps (or multiple appliances, or both) may include one or more intermediate tooth arrangements (IT As) between an original tooth arrangement (OTA) and a desired final tooth arrangement (FT A). Likewise, the appliances disclosed herein may be designed to be installed after a first or subsequently used appliance had moved the teeth from an OTA to an ITA (or from one ITA to another ITA) and was subsequently removed. Thus, the appliances of the present technology may be designed to move the teeth from an ITA to an FTA (or to another ITA). Additionally or alternatively, the appliances may be designed to move the teeth from an OTA to an ITA, or from an OTA to an FTA without changing appliances at an ITA.

[0076] In some embodiments, the appliances disclosed herein may be configured such that, once installed on the patient’s teeth, the appliance cannot be removed by the patient. In some embodiments, the appliance may be removable by the patient.

[0077] Any of the example appliances or appliance portions described herein may be made of any suitable material or materials, such as, but not limited to Nitinol (NiTi), stainless steel, beta- titanium, cobalt chrome or other metal alloy, polymers, or ceramics, and may be made as a single, monolithic structure or, alternatively, in multiple separately-formed components connected together in single structure. The connectors, biasing portions, attachment portions, etc. of an appliance can be made by cutting a two dimensional (2D) form of the appliance from a 2D sheet of material and bending the 2D form into a desired 3D shape of the appliance, according to processes as described in U.S. Patent Application No. 15/370,704 (Publ. No. 2017/0156823), filed December 6, 2016, U.S. Patent Application No. 15/929,442 (Publ. No. 2020/0345455), filed May 2, 2020, or other suitable processes.

III. Example Custom Orthodontic Brackets

[0078] Orthodontic brackets have the important function of transmitting a desired force from an orthodontic appliance to a corresponding tooth to reposition the tooth to a desired position and/or maintain a position of the tooth. In many cases, the efficiency and/or accuracy of the force transferred by the bracket depends, at least in part, on the strength of the bond between the bracket and the tooth. If the bond is too weak, the magnitude and/or direction of the force applied by the bracket will be different than the intended force, and the tooth may move to an unintended position and/or move more slowly than expected. Moreover, a weak bond may allow the bracket to separate from the tooth during use, which can cause discomfort for the patient, increase the cost of treatment, and/or interrupt or otherwise delay treatment. One way to improve bond strength between the bracket and the tooth is to increase a contact area between the bracket and the tooth. Optimizing the contact area can be difficult, however, as it requires the shape of the bracket to mimic the shape of the tooth, and the shape, curvature, and/or topography of a given tooth can vary greatly from patient to patient.

[0079] To address the foregoing challenges, the brackets of the present technology are custom-shaped to the patient’s teeth and include surface features that increase a contact area between the bracket and the tooth. In some embodiments, features on a surface of a bracket can function to increase an area of the surface, which can facilitate adhesion of a bonding agent to the bracket. Additionally or alternatively, features on a surface of a bracket can provide recesses configured to receive a bonding agent so that more bonding agent can be applied between the bracket and the tooth. Accordingly, the brackets of the present technology are configured to form strong bonds with the teeth that allow the brackets to transfer force efficiently and accurately from an orthodontic appliance to a tooth of a patient with good durability. As discussed herein, the brackets of the present technology can be customized to conform to a surface of a specific tooth and/or of a specific patient’s tooth, thereby increasing the contact area between the bracket and the tooth as compared to a conventional bracket having a generic or non-customized shape. Several brackets of the present technology can also be configured to have a relatively larger surface roughness at the side of the bracket that contacts the tooth, with a relatively smooth surface at the side of the bracket that faces the inside of the patient’s lip or the patient’s tongue (depending on whether the appliance is buccally or lingually positioned). Increasing a smoothness of the side of the bracket that faces the patient’s soft oral tissues may be associated with certain benefits such as enhanced bracket durability, patient comfort, and/or anti-pathogen properties of the surface. The novel manufacturing methods of the present technology enable this selective surface topography, as discussed in greater detail herein.

[0080] FIGS. 4A and 4B illustrate an example custom bracket 400 configured in accordance with several embodiments of the present technology. In some embodiments, for example as shown in FIGS. 4A and 4B, the bracket 400 comprises a body portion 402 configured to substantially conform to the shape of a particular patient’s tooth and a securing portion 404 configured to secure an orthodontic appliance to the bracket 400. The bracket 400 has a first side (displayed in FIG. 4A) configured to face away from a patient’s tooth when the bracket 400 is installed in the patient’s mouth and a second side (displayed in FIG. 4B) configured to be positioned on or adjacent a surface of the patient’s tooth. The bracket 400 has a first surface 406 at the first side, a second surface 408 at the second side, and a thickness 410 measured between the first and second surfaces 406, 408. The first surface 406 may comprise a surface 405 from the body portion 402 (or “body surface 405”) and a surface 413 from the securing portion 404 (or “securing surface 413”). The second surface 408 may comprise only a body surface 405.

[0081] The securing portion 404 can comprise a backing 412 and one or more arms 414 carried by the backing 412. The arms 414 can be configured to engage an attachment portion of an orthodontic appliance such that the arms 414 prevent or limit translation and/or rotation of the attachment portion relative to the bracket 400. In various embodiments, the arms 414 and backing 412 can cooperate to prevent or limit movement of an attachment portion secured to the bracket 400 along six degrees of freedom such that the attachment portion is not able to substantially slide relative to the bracket 400. Such restriction of motion of the attachment portion can improve the efficiency of the transfer of orthodontic forces from an appliance to the tooth. As shown in FIG. 4 A, one or more of the arms 414 can comprise a first end region 414a positioned at the backing 412 and/or the body portion 402 and a free second end region 414b spaced apart from the first end region 414a along a length of the arm 414. In some embodiments, for example, the arms 414 are cantilevered from a gingival portion of the backing 412. In some embodiments, the arms 414 are cantilevered from an occlusal, mesial, or distal portion of the backing 412.

[0082 ] According to several examples, each of the arms 414 comprise a connector 424 and a curved portion 422. The connector 424 can have a first end attached directly to the backing 412 and/or body portion 402 and a second end continuous with a first end of the curved portion 422. Each of the curved portions 422 can define a cavity 414c configured to receive a portion of an orthodontic appliance when the orthodontic appliance is secured to the bracket 400. As such, the curved portions 422 of the arms 414 can be configured to trap the attachment portion of an orthodontic appliance between and/or against the backing 412 and/or securing surface 413 to prevent or substantially inhibit movement of the attachment portion relative to the bracket 400. The securing portion 404 can comprise two arms, as shown in FIGS. 4A and 4B, or may comprise fewer or more than two arms (e.g., one arm, three arms, etc.).

[0083] According to some embodiments, for example as shown in FIG. 4A, the backing 412 can be recessed relative to the body surface 405 such that a thickness 410 of the bracket 400 along the backing 412 is less than a thickness 410 of the bracket 400 along the body surface 405. In some embodiments, the backing 412 can be substantially flush with the body surface 405. In any case, the backing 412 can have a local topography that facilitates a secure and low-profile engagement with a corresponding attachment portion of an appliance. As shown in FIG. 4A, in some embodiments the backing 412 is substantially flat while the surrounding body surface 405 is substantially curved (or at least not flat). This way, a substantially flat attachment portion can sit flush with the backing 412.

[0084] In some embodiments, the arms 414 are movable between an open configuration and a closed configuration. In the open configuration, an attachment portion of an orthodontic appliance is movable relative to the bracket 400. In some embodiments, while the arms 414 are in the open configuration, the attachment portion can be positioned between one or more of the arms 414 and the backing 412 of the securing portion 404 and/or the body portion 402 of the bracket 400. For example, in the open configuration the second end regions 414b of the arms 414 can be spaced apart from the backing 412 such that the attachment portion can be positioned within the cavities 414c defined by the curved portions 422 of the arms 414. As but one example, the attachment portion can be positioned occlusally of the second end regions 414b of the arms 414 and then moved gingivally such that the attachment portion is positioned buccolingually between the arms 414 and the backing 412. The arms 414 can then be moved to the closed position to prevent the attachment portion from being removed from the space between the arms 414 and the backing 412 and/or the body portion 402. In the closed position, the second end regions 414b of the arms 414 can be positioned closer to the backing 412 along the buccolingual dimension than in the open position.

[0085] In some embodiments, the arms 414 are configured to pivot and/or rotate relative to the body portion 402 and/or the backing 412 to move between the open and closed configurations. For example, the arms 414 can be configured to bend or flex about the first end regions 414a. Additionally or alternatively, the arms 414 can be configured to translate and/or deform to move between the open and closed configurations.

[0086] As shown in FIGS. 4 A and 4B, the first surface 406 can be bound by a first perimeter 416 and/or the second surface 408 can be bound by a second perimeter 418. In some embodiments, the first surface 406 and/or the second surface 408 can have a shape and/or topography substantially corresponding to a topography of the tooth and/or a surface of the tooth to which the bracket 400 is configured to be secured. A bracket 400 having a second surface 408 with a topography substantially corresponding to the topography of a surface of the tooth can be configured to form a stronger bond with the surface of the tooth relative to a bracket having a second surface 408 with a topography that does not substantially correspond to the topography of the surface of the tooth.

{0087) A topography of the first surface 406 can match a topography of the second surface 408 or the topography of the first surface 406 can be different from the topography of the second surface 408. In some embodiments, a topography of the backing 412 of the securing portion 404 can substantially correspond to a topography of a portion of an orthodontic appliance to be secured to the bracket 400, which can facilitate securing the orthodontic appliance to the bracket 400. As shown in FIG. 4A, in some embodiments the backing 412 can be substantially planar.

[0088] In some embodiments, a surface of a bracket configured to be secured to a patient’ s tooth can include one or more surface features configured to increase a bond strength between the bracket and the tooth, relative to a bracket without such features. For example, as shown in FIG. 4B, the second surface 408 of the bracket 400 can include one or more recesses 420. The recesses 420 increase a surface area of the second surface 408 and can thereby increase a contact area between the second surface 408 and the tooth, which can facilitate bonding of the bracket 400 to the tooth. In some embodiments, a bonding agent can be applied to the second surface 408 and/or the tooth. The recesses 420 can provide space for more bonding agent to be applied and/or increase a surface area of the second surface 408 that can bond with the tooth via the bonding agent. Additionally or alternatively, the second surface 408 can comprise protrusions, ridges, ribs, and/or other features configured to increase a surface area of the second surface 408 and/or facilitate bonding of the bracket 400 to the tooth.

{0089) FIG. 5 depicts brackets 400 secured to a patient’s teeth and an orthodontic appliance 502 installed in the patient’s mouth and secured to the brackets 400. The brackets 400 can have similar features as any of the brackets and/or securing members disclosed herein and/or the appliance 502 can have similar features as any of the appliances disclosed herein. As shown in FIG. 5, each of a patient’s teeth can have a different size, shape, surface area, and/or curvature. For example, the lingual surface of the central incisor is convex toward the center of the tooth whereas the lingual surface of the first premolar is concave toward the center of the tooth. Moreover, corresponding teeth can substantially vary between patients (e.g., a topography of a first premolar of one patient may be different from a topography of a first premolar of another patient). Accordingly, as described herein, it may be advantageous for a bracket to have a design based, at least in part, on a tooth to which the bracket is configured to be secured to. The bracket can be custom designed for a specific tooth and/or a specific patient. In some embodiments, the bracket has a design based, at least in part, on an average size, shape, surface area, curvature, etc. of a specific tooth in a general population. Such brackets can bond more strongly to a patient’s teeth and can be associated with improved durability and/or improved orthodontic treatment efficacy.

IV. Example Methods of Manufacturing Orthodontic Brackets

[0090] Any of the brackets of the present technology, including the customized brackets discussed with reference to FIGS. 4A and 4B for example, can be formed by additive manufacturing, which is an economical process for forming brackets with organic, complex shapes that are uniquely customized for a specific patient’s teeth. Such brackets are more durable, comfortable, and effective than standard, off-the-shelf brackets. Brackets formed by additive manufacturing may have a large surface roughness relative to brackets manufactured by conventional techniques. As previously noted, it may be advantageous for a region of a bracket configured to be secured to a tooth to have a large surface roughness to facilitate bonding of the bracket to the tooth. However, if regions of the bracket that face a patient’s tongue or lips have a large surface roughness, the bracket may cause irritation. Accordingly, in some embodiments a bracket formed by additive manufacturing can undergo a selective smoothing process such that a surface roughness of the bracket is reduced at only some regions of the bracket.

[0091 j As used herein, “surface roughness” can refer to at least one of an arithmetical mean height parameter (Ra, S _a ), a root mean square height parameter (R _q , Sq), a maximum heigh difference parameter (Rmax, Rz, Rt, S _z ), a skewness parameter (R _Sk , Ssk), a kurtosis parameter (Rku, Sku), a maximum profile valley depth parameter, a maximum profile height parameter, a mean height of profile elements parameter, combinations thereof, and/or other parameters characterizing deviations in a direction of a normal vector of the surface from its ideal or planar form and/or irregularities of the surface. Surface roughness can refer to any of the above-noted parameters or other relevant parameters defined over a specific region. The specific region can include a finite region representing less than an entire surface or an entire surface. Moreover, surface roughness can refer to an average, a root mean squared average, a median, a maximum, a minimum, etc. of any of the above-noted parameters or other relevant parameters over a specific region.

[0092] In some embodiments, a method for manufacturing an orthodontic bracket comprises obtaining a bracket digital model characterizing a bracket to be manufactured. FIG. 6 is a flow chart of an example process 600 for obtaining a digital model of a custom bracket in accordance with several embodiments of the present technology. As previously noted, in some embodiments a bracket of the present technology can have a shape based, at least in part, on a shape of the tooth to which the bracket is to be secured. Accordingly, the process 600 can include obtaining data characterizing a patient’s tooth (process portion 602). In some embodiments, the bracket can comprise a body portion configured to substantially conform to the patient’s tooth and a securing portion configured to retain an attachment portion of an orthodontic appliance. The process 600 can therefore include obtaining data characterizing a body portion of a bracket (process portion 604), obtaining data characterizing a securing portion of the bracket (process portion 606), and/or combining the data characterizing the body portion and the securing portion (process portion 608).

[0093] Obtaining tooth data characterizing a tooth of a patient to which the bracket is configured to be secured (process portion 602) can comprise optical scanning, laser scanning, cone beam computed tomography (CBCT), computed tomography (CT), obtaining and/or scanning of impressions of the patient’s tooth, or other suitable imaging techniques. In some embodiments, the tooth data characterizes one or more of the patient’s teeth and/or one or more regions of the patient’s oral tissues (e.g., gingiva, tongue, etc.). The tooth data can characterize a position of the tooth relative to others of the patient’ s teeth, a boundary surface of the tooth, a volume of the tooth, a topography of the tooth, a surface roughness of the tooth, a density of the tooth, and/or other information that may influence the orthodontic treatment. According to various embodiments, the tooth data can include coordinates of one or more locations on the tooth. The tooth data can characterize the tooth in an original position before any orthodontic treatment and/or an intermediate position after some orthodontic treatment. In some embodiments, the process 600 includes obtaining a digital model of the patient’s tooth from the tooth data. (0094) In some embodiments, the tooth data comprises a point cloud including a plurality of points and coordinates associated with each point. According to various embodiments, the OTA data can comprise image data. For example, the tooth data can comprise one or more 2D images obtained, for example, via mobile phone imaging, CT scanning, MRI, etc. In some embodiments, the tooth data comprises a tooth digital model. The tooth digital model can virtually represent or characterize one or more of the patient’s teeth and gingiva. In some embodiments, the tooth digital model comprises a mesh model (e.g., a triangle mesh model, a polygon mesh model, a volumetric mesh model, etc.), a surface model (e.g., a non-uniform rational basis spline (NURBS) surface model, a T-Spline surface model, etc.), a parametric CAD model, or another suitable type of model. The tooth digital model can be based, at least in part, on the tooth data. For example, if the tooth data comprises a point cloud, obtaining the tooth digital model can comprise converting the point cloud to a 3D surface model via surface reconstruction methods. Such surface reconstruction methods can include, for example, Delaunay tri angulation, alpha shapes, ball pivoting, or other suitable methods. In some embodiments, a 3D tooth digital model can be obtained from two or more 2D images. For example, tooth data comprising a plurality of 2D images obtained via CT scanning can be segmented to identify portions of the images that correspond to one or more specific anatomical feature (e.g., bone, soft tissue, a specific tooth or teeth, the mandible, the maxilla, the skull, etc.) and a 3D model can be generated from the segmented image data.

(0095) At process portion 604, the process 600 can include obtaining body portion data characterizing a body portion of the custom bracket. As described with reference to FIGS. 4 A and 4B, the body portion can comprise a first surface configured to face away from a patient’s tooth and a second surface configured to be secured to the patient’s tooth. Accordingly, in some embodiments, the body portion data characterizes the second surface of the body portion of the bracket. Such body portion data characterizing the second surface can substantially correspond to the tooth data. For example, the body portion data can substantially correspond to tooth data characterizing a surface of the patient’s tooth to which the second surface is configured to be secured. In such embodiments, the second surface has a topology substantially corresponding to a topology of the surface of the tooth. In some embodiments, the body portion data characterizing the second surface can be translated and/or rotated relative to the tooth data along a buccolingual dimension, an occlusogingival dimension, and/or a mesiodistal dimension. Additionally or alternatively, the body portion data can be modified relative to the tooth data such that a topology of the second surface is similar but not identical to a topology of the surface of the tooth.

[0096] Additionally or alternatively, the body portion data can characterize the first surface of the body portion of the bracket. In some embodiments, the body portion data characterizing the first surface is offset from the body portion data characterizing the second surface. For example, the body portion data characterizing the first surface can be offset from the body portion data characterizing the second surface along a buccolingual axis, an occlusogingival axis, and/or a mesiodistal axis. In some embodiments, the first surface can have a topology substantially corresponding to a topology of the second surface and/or the tooth. In some embodiments, the first surface can have a topology based on patient comfort, aesthetics, and/or other considerations. For example, it may be advantageous for the first surface to have a smoother topology to prevent the patient’s tongue from becoming irritated after contacting the first surface.

[0097] The body portion data can characterize a volume of the body portion. For example, the body portion data can characterize the second surface, the first surface, and a thickness of the body portion between the first and second surfaces. In some embodiments, the body portion data only characterizes outer surfaces of the body portion. The body portion data can comprise one or more point clouds, one or more surface models, and/or one of more volumetric models.

[0098] A design of the body portion of the bracket (e.g., a size and/or shape of the first and/or second surfaces, a thickness of the body portion, etc.) can be based, at least in part, on the tooth data. In some embodiments, the design of the body portion is based, at least in part, on a region of the tooth to which the body portion is configured to be secured, which may be based on a variety of factors. For example, the body portion can be configured to be secured to a region of a tooth such that, as the tooth moves from an original position to a desired position via orthodontic treatment, the bracket will not collide with other brackets or other teeth. As the body portion data characterizing the second surface may be derived from the tooth data characterizing the region of the tooth to which the bracket is configured to be secured, a size and/or shape of the second surface may depend on the region of the tooth to which the bracket is configured to be secured. Additionally or alternatively, the region of the tooth that the bracket is configured to be secured to can be based on a desired contact area between the bracket and tooth, patient comfort, aesthetics, and/or other relevant considerations. (0099) As shown in FIG. 6, the process 600 can include obtaining securing portion data characterizing a securing portion of the bracket (process portion 606). As previously noted, the securing portion can be configured to retain an attachment portion of an orthodontic appliance. In some embodiments, the securing member can include one or more arms, recesses, flanges, shoulders, clips, ties, and/or other suitable features configured to engage and/or retain the attachment portion. Additionally or alternatively, the securing member can include a backing configured to cooperate with the above-noted features to engage the attachment portion. The backing can be substantially flat, curved (or at least not flat), and/or shaped based on a topography of the body portion and/or the tooth. The securing portion can comprise any custom, novel, and/or commercially available orthodontic bracket. Obtaining the securing portion data can comprise imaging or scanning a physical securing portion, obtaining a digital model characterizing the securing portion, generating a digital model characterizing the securing portion, etc. For example, a digital model of the securing portion can be selected from a library of digital models characterizing a variety of securing portions. Additionally or alternatively, the securing member can be custom designed based on the patient’s tooth and/or the body portion of the bracket.

(0100) The body portion data and the securing portion data can be combined to obtain a custom bracket digital model (process portion 608). For example, suitable computer-aided design (CAD) software (e.g., MeshMixer, Solidworks, Autodesk Inventor, etc.) can be used to combine the body portion data and the securing portion data. In some embodiments, combining the data comprises virtually positioning a digital model of the securing portion (e.g., the securing portion data) at a desired positioned relative to a digital model of the body portion (e.g., the body portion data) within a virtual environment. As previously noted, in some embodiments the securing portion is positioned at the first surface of the body portion. Combining the data can include performing Boolean operations (e.g., merging, intersecting, subtracting, etc.) on the data. The bracket digital model can be obtained as and/or converted to a file format suitable for transfer to and/or use by an additive manufacturing machine. Such file formats can include, but are not limited to, STL, OBJ, PLY, AMF, 3MF, and others.

[01011 FIG. 7 is a flow chart of an example process 700 for manufacturing an orthodontic bracket in accordance with several embodiments of the present technology. As shown in FIG. 7, the process 700 can include obtaining a bracket digital model characterizing a bracket to be manufactured (process portion 702). In some embodiments, process portion 702 corresponds to process 600 previously described and shown in FIG. 6. At process portion 704, the process 700 can include forming a build piece comprising a bracket portion and a support portion. In some embodiments, any or all portions of the build piece can be based, at least in part, on the bracket digital model. As described in greater detail herein, the build piece can be formed by additive manufacturing. The process 700 can include selectively reducing a surface roughness of the build piece (process portion 706). In some embodiments, the process 700 includes reducing a surface roughness of the build piece while the support portion is attached to the bracket portion such that the support portion serves as a mask that prevents the regions of the bracket . In these embodiments and others, the process 700 can include separating the support portion from the bracket portion (process portion 708) to obtain a bracket comprising the bracket portion of the build piece. The bracket can then be installed in a patient’s mouth or can undergo further processing and/or analysis (e.g., smoothing, polishing, surface treating, etc.) before being installed in a patient’s mouth.

[01021 A bracket in accordance with several embodiments of the present technology can comprise a body portion configured to be secured to a patient’s tooth and a securing portion configured to retain an attachment portion of an orthodontic appliance. As described with reference to FIG. 6, obtaining a bracket digital model characterizing the bracket can comprise obtaining data characterizing a patient’s tooth, obtaining data characterizing a body portion of a bracket, and/or obtaining data characterizing a securing portion of the bracket. In some embodiments, the body portion data is based on the tooth data such that the body portion has a shape substantially corresponding to and/or derived from a shape of the patient’s tooth.

{01031 Additionally or alternatively, the process 700 can include obtaining a build piece digital model characterizing the build piece. Obtaining the build piece digital model can include, for example, obtaining a bracket digital model characterizing the bracket portion of the build piece, obtaining a support digital model characterizing the support portion of the build piece, and virtually merging the bracket and support digital models.

{0104] At process portion 704, the process 700 can include forming a build piece including a bracket portion and a support portion. The bracket portion can have a shape corresponding to and/or derived from the bracket digital model. In some embodiments, the support portion is configured to facilitate forming the build piece and/or selectively reducing a surface roughness of the build piece. FIG. 8 illustrates an example build piece 800 comprising a bracket portion 802 and a support portion 804. As described with reference to FIGS. 4A and 4B, the bracket portion 802 can include a body portion 806 and a securing portion 812 disposed on and/or carried by the body portion 806. The body portion 806 can have a first surface 808 and a second surface 810. The first surface 808 can be configured to face away from a patient’s tooth when the second surface 810 is secured to the patient’s tooth. The bracket portion 802 can include a securing portion 812 and, in some embodiments, the securing portion 812 can be positioned at the first surface 808. The securing portion 812 can include one or more arms 814 configured to retain an attachment portion of an orthodontic appliance to prevent or limit translation and/or rotation of the attachment portion. As will be described in greater detail herein, in some embodiments the support portion 804 serves to provide structural integrity to the build piece 800 while the build piece 800 is being formed and/or mask regions of the build piece 800 to facilitate selectively reducing a surface roughness of the build piece 800.

[01051 In some embodiments, forming the build piece (process portion 704) comprises obtaining instructions for an additive manufacturing machine. Obtaining the instructions can comprise, for example, importing the build piece digital model and/or the bracket digital model into suitable slicing software, orienting the digital model relative to a virtual build surface and/or within a virtual build volume, generating support structures within the digital model and/or generating distinct a digital model of the support structures, virtually separating the digital model into finite layers, creating a tool path, and/or specifying parameters (e.g., speed, time, temperature, resolution, etc.) that the additive manufacturing machine should use. Such suitable slicing software can include, but is not limited to, Cura, Netfabb Standard, PrusaSlicer, Simplify3D, OctoPrint, Slic3r, MatterControl, MakerBot Print, Repetier, ideaMaker, ChiTuBox, Z-Suite, IceSL, Astroprint, CraftWare, SelfCAD, 3DPrinterOS, KISSlicer, Tinkerine Suite, SuperSlicer, Pathio, and others. In some embodiments, the instructions comprise a geometric code (e.g., G-code) and/or another suitable numerical control programming language.

[0106] As previously noted, in some embodiments the build piece can be formed by an additive manufacturing process. The additive manufacturing process can comprise a three- dimensional (3D) printing process in which a 3D printer forms the build piece. In some embodiments, the additive manufacturing process comprises at least one of direct metal laser sintering (DMLS), selective laser melting (SLM), fused deposition modeling (FDM), fused filament fabrication (FFF), binder jetting, combinations thereof, and/or other suitable additive manufacturing processes. Forming the build piece by the additive manufacturing process can comprise successively fusing particles of a material. In some embodiments, fusing the particles can comprise delivering thermal energy to the particles. For example, thermal energy can be delivered to the particles via a laser, a hotend, etc. Additionally or alternatively, mechanical forces and/or chemical agents can be applied to the particles to cause them to fuse. In some embodiments, the build piece can be formed by successively fusing particles in successive layers. For example, forming the build piece can comprise successively fusing particles in a first, two-dimensional (2D) layer, fusing particles in a second 2D layer on the first 2D layer, fusing particles in a third 2D layer on the second 2D layer, and so on.

[0107} The build piece can be formed from a material comprising a metal, a ceramic, a polymer, or others. In some embodiments, the material comprises stainless steel, cobalt-chromium, titanium, gold, platinum, alloys thereof, or other suitable metals or metal alloys. Additionally or alternatively, the material can comprise a thermoplastic, a photopolymer, a biological material, an aluminum oxide, or another suitable material. In some embodiments, the material is biocompatible. The material can comprise a powder, a filament, a liquid, and/or another suitable form.

[0108] In some embodiments, the build piece can be formed on a build surface such as a bed of a 3D printer, a build plate of a 3D printer, a workbench, etc. As an example, FIG. 8 illustrates the build piece 800 formed on a build surface 816. As previously noted, forming a bracket by an additive manufacturing process can comprise fusing particles of a material in successive layers. Accordingly, a first layer of the build piece 800 can be formed on the build surface 816, a second layer can be formed on the first layer, a third layer can be formed on the second layer, and so on. In a layer-by-layer approach, each layer should generally be supported by the build surface or the layers between the layer being formed and the build surface. If the bracket has a shape comprising overhangs, bridges, or angles generally greater than 45 degrees, structural reinforcement may be required to prevent deformation of the build piece 800 during the additive manufacturing process.

{0109] Thus, in some embodiments the build piece 800 comprises a support portion 804 positioned between one or more regions of the bracket portion 802 of the build piece 800 and the build surface 816 (see FIG. 8). Additionally or alternatively, the support portion 804 can be positioned between one or more regions of the bracket portion 802 and another region of the build piece 800 that is sufficiently supported. The support portion 804 can comprise a single, continuous support portion 804 or multiple, separated support portions 804. The support portion 804 can be configured to support a weight of the bracket portion 802 as the bracket portion 802 is formed. For example, the support portion 804 can be configured to support the weight of any regions of the bracket portion 802 that are not directly connected to the build surface 816, a sufficiently supported region of the bracket portion 802, and/or another structural support element. In some embodiments, a support portion 804 may not be required for structural reinforcement of the build piece 800. Additionally or alternatively, the support portion 804 can be configured to secure the bracket portion 802 of the build piece 800 to the build surface 816. As will be described in greater detail herein, the support portion 804 can be sacrificial and configured to be separated from the build piece 800.

(0110) The support portion 804 can comprise structural elements 818 such as struts, rods, beams, ties, trusses, braces, plates, shells, and/or other structural elements. In some embodiments, the structural elements comprise one or more first structural elements 818a and/or one or more second structural elements 818b. The first structural elements 818a can extend along a direction that is angled with respect to the build surface 816 (e.g., direction D1 shown in FIG. 8). The first structural elements 818a can be configured to support compressive, tensile, bending, shear, and/or torsional loads, for example. Although FIG. 8 depicts a plurality of first structural elements 818a that each extend along the same direction Dl, the support portion 804 can comprise any suitable number of first structural elements 818a extending along any suitable directions. Moreover, the first structural elements 818a can comprise any suitable shape, density, design, material, etc. Although FIG. 8 depicts the first structural elements 818a spaced apart from one another, in some embodiments the first structural elements 818a can be connected and/or can abut one another. The second structural elements 818b can extend along a direction substantially parallel to the build surface 816 (e.g., direction D2 shown in FIG. 8). As shown in FIG. 8, in some embodiments the support portion 804 comprises one second structural element 818b. The second structural element 818b can comprise a raft, a brim, and/or a skirt. The second structural element 818b can be configured to facilitate adhesion of the build piece 800 to the build surface 816 and/or prevent the build piece 800 from warping while being formed. In some embodiments, any of the structural elements 818 can be arranged in a random pattern, a lattice pattern, a tree-type pattern, and/or any other suitable pattern. (0111) A location of the support portion 804 relative to the bracket portion 802 can be based, at least in part, on a type of the additive manufacturing process, parameters of the additive manufacturing process (e.g., print speed, temperature, etc.), the material used to form the build piece 800, a geometry of the bracket portion 802, a desired surface roughness of certain regions of the bracket portion 802, and/or an orientation of the bracket portion 802 relative to the build surface 816. For example, as discussed herein, it may be beneficial for a bracket to have a rough tooth-facing surface to facilitate bonding of the bracket to a tooth and a smooth tongue-facing surface for patient comfort. In such embodiments, the support portion 804 may be positioned at the tooth-facing surface. In FIG. 8, the second surface 810 is the tooth-facing surface and the support portion 804 is positioned between the second surface 810 and the build surface 816.

(0112) The bracket portion 802 and the support portion 804 of the build piece 800 can be formed from the same material and/or by the same additive manufacturing process. Additionally or alternatively, the support portion 804 and the bracket portion 802 can be formed from different materials and/or by different additive manufacturing processes. In some embodiments, the support portion 804 can be formed of a material having one or more properties such that the support portion 804 can be easily removed from the build piece 800. For example, the support portion 804 can be formed from a material that is configured to dissolve, a soft material, a low-strength material, etc.

[0113] In some embodiments, the support portion 804 is integral with the bracket portion 802. The support portion 804 can be integral with the bracket portion 802 at an interfacial region 820 of the bracket portion 802. The interfacial region 820 can comprise a region of the bracket portion 802 in contact with the support portion 804. For example, as shown in FIG. 8, the interfacial region 820 can comprise the region(s) of the bracket portion 802 that contact the structural elements 818. The interfacial region 820 can comprise a region of the second surface 810 of the bracket portion 802 and/or the entire second surface 810. In some embodiments, the support portion 804 is configured to be separated from the bracket portion 802 at the interfacial region. Accordingly, the interfacial region 820 can have one or more properties configured to facilitate breaking, debonding, and/or otherwise separating the support portion 804 from the bracket portion 802 at the interfacial region 820. For example, a cross-sectional area of cylindrical first structural elements 818a can be smaller at or adjacent to the interfacial region 820. (0114) After the build piece has been formed, the process 700 can include processing the build piece to obtain an intended orthodontic bracket. In some embodiments, processing the build piece comprises separating the build piece from a build surface via cutting, wire EDM, and/or other suitable techniques. As shown in FIG. 7, the process 700 can include selectively reducing a surface roughness of the bracket portion (process portion 706) and/or separating the support portion from the bracket portion (process portion 708). Additionally or alternatively, the build piece can be processed and/or analyzed via any other suitable technique (e.g., heat treating, stress- relieving, pressing, machining, inspecting, testing, etc.) to obtain the desired bracket.

[0115] At process portion 706, the process 700 can include reducing a surface roughness of the build piece, which can comprise subjecting the build piece to one or more suitable surface modification processes. Such surface modification processes can comprise any mechanical, chemical, or electrical process for changing a property of a surface. A surface modification process in accordance with the present technology can comprise, for example, electropolishing, grinding, polishing, buffing, lapping, abrasive blasting, honing, electrical discharge machining (EDM), milling, lithography, etching, chemical milling, laser texturing, shot peening, mechanical polishing, traditional electropolishing, dry electropolishing, chemical etching, coating, ultrasonic cleansing, sterilizing, and/or other suitable processes. In some embodiments, reducing a surface roughness of the build piece comprises subjecting the build piece to any of the above-noted surface modification processes or others in a single step or in multiple, sequential steps.

(0116) As previously noted, it may be beneficial for certain regions of a bracket have a larger surface roughness than other regions of the bracket. Accordingly, in some embodiments the process 700 includes reducing a surface roughness of only some regions of the build piece. Selectively reducing a surface roughness of the build piece can comprise reducing a surface roughness of one or more regions of the bracket portion of the build piece and/or one or more regions of the support portion of the build piece. In some embodiments, a surface roughness of the build piece can be reduced except at and/or adjacent to the interfacial region. Selectively reducing a surface roughness of the build piece can comprise masking one or more regions of the build piece and/or exposing one or more regions of the build piece. A surface roughness of the exposed regions can be reduced without substantially reducing a surface roughness of the masked regions. In some embodiments, a surface roughness of the exposed regions can be reduced to a much greater degree than a surface roughness of the masked regions is reduced. (0117) Masking one or more regions of the build piece can comprise forming a mask on the build piece after the build piece has been formed by additive manufacturing. In some embodiments, the mask can be formed on only regions of the build piece intended to have a greater surface roughness. Additionally or alternatively, the mask can be formed on all of the build piece and the mask can be removed at and/or adjacent to regions of the build piece that are intended to be exposed.

(0118) Although a mask can be applied to the build piece after forming the build piece and/or portions of the mask can be removed to expose certain regions of the build piece, these processes may require additional processing steps that can be costly and/or time-consuming. Thus, an aspect of the present technology includes utilizing the support portion of the build piece as the mask. The build piece can be subjected to a surface modification process while the support portion is attached to the bracket portion such that regions of the bracket portion at and/or adjacent to the support portion are not smoothed. For example, a surface roughness of the interfacial region can remain substantially unchanged or may be only slightly reduced while a surface roughness of the other regions of the bracket portion is reduced and/or reduced to a greater extent. Regions of the bracket portion directly in contact with the support portion and/or regions of the bracket portion enclosed by the support portion can be masked such that the surface roughness of such regions is substantially unchanged or only slightly changed. For example, in embodiments in which a surface roughness of the build piece is reduced via dry electropolishing, the support portion can physically block electrolytic ions from reaching the interfacial region and/or the second surface of the bracket portion. By using the support portion of the build piece to structurally support the bracket portion and prevent certain regions of the bracket portion from being smooth, the process 700 can limit costly and slow processing steps.

[0119] The process 700 can proceed at process portion 708 with separating the support portion of the build piece from the bracket portion. Separating the support portion from the bracket portion can comprise delivering energy and/or a separating agent to the support portion and/or the bracket portion to weaken bonds between the bracket and support portions. In some embodiments, separating the support portion from the bracket portion can comprise applying mechanical forces (e.g., via cutting, sanding, filing, grinding, scraping, machining, drilling, etc.) to the support portion and/or the bracket portion to break the bonds between the bracket and support portions. Additionally or alternatively, thermal energy can be delivered to the support portion and/or the bracket portion. For example, the support portion can be heated until the material forming the support portion softens or melts sufficiently to remove the support portion from the bracket portion. In some embodiments, the support portion can comprise a material configured to be dissolved in the presence of a solvent. For example, the material can comprise polyvinyl alcohol, high impact polystyrene, and/or another suitable dissolvable material. The solvent can comprise water, an oil, an alcohol, a ketone, and/or another suitable solvent. According to various embodiments, the support portion can be separated from the bracket portion without substantially damaging or otherwise adversely affecting the bracket portion.

[0120| In some cases, some material forming the support portion may remain attached to the bracket portion (e.g., at the interfacial region) after the support portion has been separated from the bracket portion. In some embodiments, this remaining material can be removed by further processing (e.g., by additional sanding, machining, etching, etc.). However, in some embodiments this remaining material may advantageously contribute to a larger surface roughness of a tooth facing surface of the bracket portion. In such embodiments, the remaining material may be left attached to the bracket portion.

[0121] FIG. 9 depicts an example of a build piece 900 configured in accordance with several embodiments of the present technology. In some embodiments, for example as shown in FIG. 9, the build piece 900 can include multiple bracket portions 902 (for simplicity, only one of the bracket portions 902 is labelled in FIG. 9). Additionally or alternatively, the build piece 900 can include a support portion 904. As shown in FIG. 9, the support portion 904 can comprise a first region 904a and one or more second regions 904b. The second regions 904b can couple the bracket portions 902 to the first region 904a and/or to one another. For example, as shown in FIG. 9, each second region 904b can extend between a first end at the first region 904a and a second end at one of the bracket portions 902. In some embodiments, the support portion 904 positions the bracket portions 902 in a specific arrangement relative to one another. As shown in FIG. 9, the first region 904a of the support portion 904 can be generally arch-shaped such that the bracket portions 902 are positioned in an arrangement substantially corresponding to and/or derived from an intended arrangement of the bracket portion 902 in the patient’s mouth. For example, the bracket portion 902 at the apex of the arch-shaped first region 904a of the support portion 904 can be configured to be secured to a central incisor of a patient. By each of the bracket portions 902 being secured to the support portion 904 in a specific arrangement, the support portion 904 can facilitate tracking and traceability of the bracket portions 902 during manufacturing.

[0122] In some embodiments, the build piece 900 can include one or more marking regions 906 including indicia 908 configured to communicate information corresponding to at least one of an identity of the patient associated with the brackets, a tooth to which each bracket is intended to be secured to, an intended orientation and/or position of the brackets with respect to the patient’s teeth, an origin of the build piece (e.g., a serial number, a lot number, a stock keeping unit, etc.), and/or other useful information. The indicia 908 can include at least one of a number, a letter, a symbol, a color, a shape, or a pattern. For example, the ‘R’ indicia 908 shown in FIG. 9 can indicate that the bracket portions 902 adjacent to the ‘R’ indicia 908 are configured to be secured to the teeth on the right half of the patient’s dental arch.

[0123] As previously described, the support portion 904 can be configured to support a weight of the bracket portions 902 and/or prevent a surface roughness of certain regions of the bracket portions 902 from being reduced. Although FIG. 9 depicts the first region 904a and the second regions 904b of the support portion 904 as substantially solid, as previously noted the support portion 904 and any region thereof can be hollow, patterned, etc. For example, the first region 904a may comprise a shell such that an underside of the first region 904a opposite of the second regions 904b is substantially hollow. Additionally or alternatively, the second regions 904b can comprise a plurality of structural elements (e.g., rods, trusses, etc.) that are spaced apart, interconnected, and/or extending along different directions.

[0124] The build piece 900 can be separated from a build surface and/or removed from an additive manufacturing machine with the bracket portions 902 secured to the support portion 904. In some embodiments, the build piece 900 can be processed as described with reference to FIG. 7. For example, the build piece 900 can be electropolished with the bracket portions 902 secured to the support portion 904 so that a surface roughness of lingual (or otherwise soft-tissue facing) surfaces 910 of the bracket portions 902 is reduced while a surface roughness of buccal surfaces (or otherwise tooth facing) of the bracket portions 902 is not substantially reduced.

[0125] To obtain the desired brackets, the bracket portions 902 of the build piece 900 can be separated from the support portion 904. As previously noted, in some embodiments the bracket portions 902 can be separated from the support portion at an interfacial region 914. The bracket portions 902 can be separated from the support portion 904 by applying tensile, compressive, shear, torsion, bending, and/or other forces to the bracket portions 902. For example, a human operator can pull the bracket portions 902 to separate them from the support portion 904. Additionally or alternatively, tools and/or solvents may be used to facilitate separating the bracket portions 902 from the support portion 904.

V. Orthodontic Brackets Configured to Influence Interarch Relationships

(0126) In some embodiments, an orthodontic bracket can be configured to influence a relative positioning of a patient’s upper and lower dental arches (e.g., an interarch relationship). As described in greater detail below, designing a bracket based, at least in part, on a tooth to which the bracket is to be secured and/or forming the bracket by an additive manufacturing process can facilitate forming a bracket configured to influence a patient’s interarch relationship. FIGS. 10A-13 illustrate examples of such brackets.

[0127] FIGS. 10A and 10B illustrate example orthodontic brackets 1000 configured to modify a position of one of a patient’s dental arches relative to the patient’s other dental arch. Such brackets 1000 can be configured to treat a class II malocclusion or a class III malocclusion. FIG. 10A is a fragmentary sagittal view of a patient’s mouth showing lingual surfaces of the patient’s teeth and FIG. 10B is a front view of two of the patient’s teeth. The orthodontic brackets 1000 can include a body portion 1002, a securing portion 1004, and a wing portion 1006. In some embodiments, the brackets 1000 are formed by additive manufacturing. As described herein, the body portion 1002 can be configured to be secured to a tooth and/or the securing portion 1004 can be configured to secure an attachment portion of an orthodontic appliance to the bracket 1000 and the thereby the tooth. In some embodiments, the body portion 1002 is configured to conform to one or more surfaces of the tooth. The body portion 1002 can conform to a lingual surface or buccal surface of the tooth. Additionally or alternatively, the body portion 1002 can conform to an occlusal surface of the tooth. As shown in FIGS. 10A and 10B, the wing portions 1006 can extend occlusally and/or buccally. The wing portions 1006 can extend from a lingual region of the body portion 1002 and/or an occlusal region of the body portion 1002. The wing portions 1006 can be configured to engage one another such that, when they engage, the wing portions 1006 shift the patient’ s mandible anteriorly (to treat a class II malocclusion) or posteriorly (to treat a class III malocclusion). The effects of the brackets 1000 can be dental and/or skeletal. Movement of the patient’s mandible via engagement of the wing portions 1006 can be used, for example, to treat malocclusions, temporomandibular joint issues, sleep apnea, and/or other orthopedic issues. In some embodiments, movement of the patient’s mandible via the wing portions 1006 can facilitate growth of the patient’s jaws.

[0128] The teeth on which the wing portions 1006 are positioned and the directi on(s) in which the wing portions 1006 extend can be selected based on an intended movement of the patient’s mandible. To move the mandible anteriorly or posteriorly, the wing portions 1006 can be positioned on the molars, premolars, canines, or other teeth. In some embodiments, wing portions 1006 configured to move the patient’s mandible anteriorly or posteriorly can extend buccally from their respective brackets 1000. To move the patient’s mandible laterally or medially, the wing portions 1006 can be positioned on the anterior teeth. In some embodiments, overcorrection can be applied to movements of the patient’s mandible due to the wing portions 1006 to facilitate positioning of the mandible in a desired position.

[0129] In some embodiments, a bracket of the present technology can comprise one or more structural features configured to facilitate use of auxiliary orthodontic devices and/or appliances. For example, orthodontic elastics can be used to treat class II and class III malocclusions; however, each end of the elastics must be secured to the patient’s teeth. According to various embodiments, a bracket such as bracket 1100 shown in FIGS. 11A and 11B and/or bracket 1200 shown in FIGS. 12A and 12B can be configured to facilitate securing an auxiliary device or appliance to the patient’s teeth. FIGS. 11 A and 12A are side views of bracket 1100 and bracket 1200, respectively, and FIGS. 11B and 12B are front views of bracket 1100 and bracket 1200, respectively. The bracket 1100 can comprise a body portion 1102 and an attachment portion 1104 and/or the bracket 1200 can comprise a body portion 1202 and an attachment portion 1204. The body portion 1102, 1202 can be configured to be secured to a lingual, buccal, and/or occlusive surface of a patient’s tooth. In some embodiments, the body portion 1102, 1202 is configured to substantially conform to the patient’s tooth. The attachment portion 1104, 1204 can be configured to secure an auxiliary device to the bracket 1100, 1200. For example, a first end of an elastic can be secured to an attachment portion 1104, 1204 on a bracket 1100, 1200 secured to an upper tooth of a patient and a second end of the elastic can be secured to an attachment portion 1104, 1204 on a bracket 1100, 1200 secured to a lower tooth of a patient. As shown in FIGS. 11A and 12A, the attachment portion 1104, 1204 can extend away from the body portion 1102, 1202. In some embodiments, a direction along which the attachment portion 1104, 1204 extends can be based, at least in part, on a direction of intended forces to be applied to the tooth to which the bracket 1100, 1200 is secured via the auxiliary device. For example, the hook-like shape of the attachment portion 1204 of FIG. 12 may be preferrable as compared to the attachment portion 1104 of FIG. 11 for use with an elastic configured to apply force generally along the direction A1 labelled in FIG. 12A.

{0130) FIG. 13 illustrates an example bracket 1300 comprising a body portion 1302, a securing portion 1304, and a blocking element 1306. In some embodiments, the blocking element 1306 is integral with the body portion 1302 of the bracket 1300. The blocking element 1306 can have a thickness that is greater than a thickness of the body portion 1302. The bracket 1300 and/or any portion thereof can be formed via additive manufacturing, investment casting, and/or another suitable method of manufacturing. As shown in FIG. 13, when the bracket 1300 is secured to the patient’s tooth, the blocking element 1306 can be positioned on or adjacent to an occlusal surface of the tooth.

[0131 } In some cases, brackets bonded to teeth in a patient’ s upper dental arch can interfere with brackets bonded to teeth in a patient’s lower dental arch. For example, during chewing a bracket on a patient’s right upper first molar can collide with a bracket on the patient’s right lower first molar and/or the patient’s right lower first molar itself. Collision of a bracket with another bracket or a tooth could cause damage to the bracket and/or tooth. In some embodiments, such collision can cause the bracket to separate (e.g., debond, etc.) from the tooth to which was secured. Accordingly, the blocking element 1306 can function to prevent collision of the bracket 1300 with a tooth and/or another bracket. Additionally or alternatively, in some embodiments the blocking element 1306 can be configured to apply intrusive forces to a corresponding tooth in an arch opposite of the arch to which the bracket 1300 with the blocking element 1306 is applied.

[0132j Any of the previously-described bracket components configured to influence a patient’s interarch relationship (e.g., the wing portions 1006, the structural components 1104, 1204, the blocking element 1306, etc.) can be configured to be secured to a patient’s tooth but not to an orthodontic appliance. For example, a bracket of the present technology can be similar to the brackets illustrated in FIGS. 10A and 10B, but may exclude the securing portions 1004 such that the wing portions 1006 are secured to the patient’s teeth and may influence the patient’s interarch relationship without substantially influencing a patient’s intraarch relationship. In embodiments in which a bracket does not include the securing portion configured to be secured to an orthodontic appliance, the bracket may still include a body portion configured to be secured to one or more surfaces of the patient’s teeth. In these and other embodiments, the body portion may be configured to substantially conform to one or more surfaces of a patient’s tooth.

{0133) Any of the previously-described bracket components (e.g., the wing portions 1006, the structural components 1104, 1204, the blocking element 1306, etc.) can be formed by an additive manufacturing process. Such components can be formed monolithically with a body portion of the bracket or formed independently of the body portion and joined to the body portion after being formed. Some aspects of the present technology include a fixture configured to facilitate securing a bracket and/or components thereof to a patient’s tooth. The fixture can be configured to accurately and precisely position the bracket and/or components at the patient’ s tooth such that the bracket and/or components can be secured to the tooth in a desired location. For example, the fixture can comprise an indirect bonding tray.

Conclusion

{0134) Although many of the embodiments are described above with respect to systems, devices, and methods for orthodontic appliances positioned on a lingual side of a patient’s teeth, the technology is applicable to other applications and/or other approaches, such as orthodontic appliances positioned on a facial side of the patient’s teeth and/or other orthodontic devices. Moreover, other embodiments in addition to those described herein are within the scope of the technology. Additionally, several other embodiments of the technology can have different configurations, components, or procedures than those described herein. A person of ordinary skill in the art, therefore, will accordingly understand that the technology can have other embodiments with additional elements, or the technology can have other embodiments without several of the features shown and described above with reference to FIGS. 1A-13.

{0135] The descriptions of embodiments of the technology are not intended to be exhaustive or to limit the technology to the precise form disclosed above. Where the context permits, singular or plural terms may also include the plural or singular term, respectively. Although specific embodiments of, and examples for, the technology are described above for illustrative purposes, various equivalent modifications are possible within the scope of the technology, as those skilled in the relevant art will recognize. For example, while steps are presented in a given order, alternative embodiments may perform steps in a different order. The various embodiments described herein may also be combined to provide further embodiments.

[0136] As used herein, the terms “generally,” “substantially,” “about,” and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent variations in measured or calculated values that would be recognized by those of ordinary skill in the art.

[01371 Moreover, unless the word “or” is expressly limited to mean only a single item exclusive from the other items in reference to a list of two or more items, then the use of “or” in such a list is to be interpreted as including (a) any single item in the list, (b) all of the items in the list, or (c) any combination of the items in the list. Additionally, the term "comprising" is used throughout to mean including at least the recited feature(s) such that any greater number of the same feature and/or additional types of other features are not precluded. It will also be appreciated that specific embodiments have been described herein for purposes of illustration, but that various modifications may be made without deviating from the technology. Further, while advantages associated with certain embodiments of the technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein.