Manufacturing patient-specific orthodontic tubes

Abstract

The embodiments relate to a methodology for direct manufacturing of customized labial / lingual orthodontic tubes by using ceramic slurry-based additive manufacturing (AM) technology. For example, a method for manufacturing customized ceramic labial / lingual orthodontic tubes by additive manufacturing includes measuring dentition data of a patient's teeth profile based on dentition data, creating a three-dimensional computer-aided design (3D CAD) model of the patient's teeth and saving the 3D CAD model, designing a virtual 3D CAD tube structure model of a single labial or lingual tube structure based on the 3D CAD model, The method can include importing data relating to the 3D CAD tube structural model into an additive manufacturing machine, and using the additive manufacturing machine to directly manufacture the tube by additive manufacturing from inorganic materials including at least one of ceramic, polymer-derived ceramic, and polymer-derived metal.

Description

[Technical field]

[0001] Related Publications This application is a related application to U.S. Provisional Application No. 63 / 318,954, entitled "MANUFACTURE OF PATIENT-SPECIFIC ORTHODONTIC TUBE," filed March 11, 2022, and U.S. Provisional Application No. 63 / 195,052, entitled "MANUFACTURE OF PATIENT-SPECIFIC ORTHODONTIC TUBES," filed May 30, 2021, and claims priority to such provisional application under 35 U.S.C. § 119, each of which is incorporated herein by reference in its entirety.

[0002] One embodiment of the present invention generally relates to the manufacture of ceramic labial / lingual orthodontic tubes for straightening teeth and correcting malocclusions. More specifically, one embodiment of the present invention relates to a methodology for the direct manufacture of customized labial / lingual orthodontic tubes by using ceramic slurry-based additive manufacturing (AM) technology. [Background technology]

[0003] Orthodontics is widely employed in clinics to correct malocclusions and align teeth. In the traditional method, preformed brackets and tubes are bonded to the teeth, and elastic metal wires of round, square, or rectangular cross-sectional shapes are threaded through slots in the tubes to provide the driving force. The fitting of the brackets and tubes to each individual tooth is achieved by filling the gaps between the tooth surface and the surfaces of the brackets and tubes with adhesive. This ensures that the brackets and tubes are bonded to the teeth such that the slots in the brackets and tubes lie in a roughly flat horizontal plane (depending on the manufacturing accuracy) when the teeth are moved into their final positions. Summary of the Invention [Problem to be solved by the invention]

[0004] Some embodiments of the present invention provide improved techniques for creating custom lingual or labial ceramic orthodontic tubes and provide the ability to manufacture such tubes in-house.

[0005] Preformed edgewise tubes may not have a prescription and require adjustment of the archwire. Alternatively, edgewise tubes can have the ideal prescription for angulation, inclination, or ingestive changes of specific teeth in what are called "straight-wire appliances". Because tube pads are not typically custom-made for each patient's teeth, tube placement is the responsibility of the clinician, which can introduce errors and generally increases the number of patient visits and overall treatment time. These tubes are typically prefabricated. Misalignment when bonding the tubes to the teeth can be corrected by compensating for wire bending or by debonding and repositioning the tubes, both of which increase time and cost. Custom metal lingual tubes are now available and are manufactured centrally based on 3D scans or impressions of the dentition, shipped back to the clinician, and transferred to the patient by indirect bonding.

[0006] Selective laser melting (SLM) is a 3DAM technology that has been used to create custom metal lingual brackets and tubes (see, for example, U.S. Patent No. 8,694,142), but this technology has poor resolution and surface finish. True custom labial tubes have been used, but custom positions of standard non-custom tubes can be created by indirect bonding with the inherent tolerances of the tube itself. Many of the current true custom labial systems (SURESMILE® Inc.) rely heavily on making custom bends to wires based on 3D scans rather than creating true straight-wire orthodontic appliances. For example, U.S. Patent No. 8,690,568 provides a method for welding metal bracket slots to a genuine metal bracket base in a custom position, but does not explain how to create custom bracket bases or how to create beautiful non-metal brackets.

[0007] These partially custom metal brackets and tubes (similar to tubes) suffer from inaccurate slot positioning and premature delamination due to stock bases that do not match the tooth morphology, making them unattractive to older patients who prefer non-metallic appliances for aesthetic reasons. Ceramic brackets have been commercially available and researched since the 1980s, and are a desirable material compared to metal brackets due to their excellent esthetics, creep resistance, rigidity, biocompatibility, corrosion resistance, stability in the oral environment, and non-toxic nature. However, non-customized ceramic tubes have only been available since 2018, as the need for esthetics to replace metal is less important to patients, as they are located within the brackets in the oral cavity. Ceramic brackets and tubes are primarily manufactured by injection molding, but they have manufacturing limitations. For example, it may be difficult or impossible to use injection molding to create undercuts to increase the mechanical bond strength of the tubes to the dental adhesive.

[0008] Unlike metals, ceramic tubes do not bend to debond, but instead must fracture the connection between the tube and the adhesive material. The mechanical properties of ceramics and this debonding mechanism increase the risk of damaging the enamel when debonding the tube if the tube cannot be easily separated from the tooth. In this case, diamond burrs must be used to remove the tube from the tooth, which can create sparks, take a long time, and result in a poor patient and provider experience.

[0009] Currently, there are no commercially available ceramic tubes that delaminate by controlled fracture along the lines of a "stress concentrator" designed to force the tube to break at a specific location when pressure is applied. Custom shapes must also be used, as the static shape of the stress concentrator will not provide a consistent delamination experience depending on the thickness of the tube (in-out) and its exact location on the tooth.

[0010] Currently, no system exists for creating aesthetic custom lingual or labial ceramic orthodontic tubes, nor are there any custom bracket and tube systems that can be manufactured 100% in-house by trained members of a private orthodontic practice. A need has arisen for more efficient and accurate techniques for creating custom lingual and labial ceramic orthodontic tubes, and more aesthetic labial tubes.

[0011] Some embodiments of the present invention can be used to solve problems encountered with current manufacturing techniques for orthodontic tubes for straight-wire appliances. For example, in one embodiment, a method for direct manufacturing of customized lingual / labial tubes can be provided by utilizing any number of ceramic slurry-based AM techniques, examples of which include digital light processing (DLP), laser photopolymerization stereolithography, jet printing (including particle jetting, nanoparticle jetting), layered slurry deposition (LSD), or laser-induced slip casting. Slurry is defined as inorganic particles dispersed in a liquid, which may be photopolymerizable or polymerized by other mechanisms.

[0012] Similarly, similar methods can be used to create metal tubes where the inorganic material in the slurry is metal. Examples of items that can be produced include labial / lingual tubes customized for individual teeth and craniofacial features, where the tubes may have fault lines / grooves (also called fracture grooves, stress concentrators, or separation features) designed into them that fit directly onto the teeth. Ceramic slurry-based AM can be performed on devices small enough to fit comfortably in a commercial orthodontic laboratory, and is now affordable given the market price and in-house volume of non-custom and custom tubes.

[0013] For example, in some embodiments, a method for manufacturing customized ceramic labial / lingual orthodontic tubes by ceramic slurry-based AM may include measuring dentition data of a patient's tooth profile, creating a three-dimensional computer-aided design (3D CAD) model of the patient's teeth using reverse engineering based on the dentition data, storing the 3D CAD model in a computer, designing a 3D CAD tube structure model of a single labial or lingual tube structure, importing data related to the 3D CAD tube structure model into a ceramic slurry-based AM machine, and directly producing the tube (green part) by layer manufacturing on the ceramic slurry-based AM machine. Processing of the tube can be performed in a sintering furnace and a degreasing furnace before direct use or other post-processing steps related to surface properties.

[0014] The 3D CAD tube structural model may include data representing at least the following: a) a tube pad (base) having recesses and / or undercuts on the adhesive surface of the tube to contact the specific tooth surface, b) fracture grooves (also called fracture grooves, stress risers, or separation features) that conform to the patient's teeth to facilitate debonding, c) slots for positioning according to the patient's orthodontic needs, d) tube material, e) specific tooth profile, f) tube guides to guide the three-dimensional placement of the tube on the tooth.

[0015] The ceramic slurry-based AM machine may include a molding compartment including a platform and plunger for directly creating the tube by layer manufacturing, a material compartment, an LED light source for digital light processing, or a print head including at least one ejection nozzle used in "jet" printing, where the tube is created by layer manufacturing using slicing software that divides a 3D CAD tube structural model into layers, obtaining a horizontal cross-sectional model of each layer such that the shape of each layer created by the ceramic slurry-based AM machine matches the 3D CAD structural data.

[0016] The ceramic slurry-based AM machine may include a vat adapted to hold the tube during production, a horizontal build platform adapted to be held at a settable height above the vat bottom, an exposure unit controlled to position-selectively expose a surface on the horizontal build platform with an intensity pattern having a predetermined geometric shape, and a control unit adapted to receive a 3D CAD tube structure model and to polymerize in successive exposure steps overlapping layers on the build platform using the 3D CAD tube structure model, each with a predetermined shape, and to control the exposure unit to adjust the relative position of the build platform with respect to the vat bottom after each exposure step of the layers to successively build up an object with a desired shape resulting from the sequence of the geometric shapes of the layers.

[0017] The exposure unit further includes a laser as a light source, the light beam of which can be continuously scanned over the exposure area via a movable mirror controlled by the control unit.

[0018] Ceramic slurry-based AM machines may include a light source that is a laser or LED light source. The light source in a DLP machine may emit wavelengths between 400 and 500 nm. DLP machines may include a digital light processing chip as a light modulator. The digital light processing chip may be a micromirror array or an LCD array. Alternatively, ceramic slurry-based AM machines may use jetting technology, whereby a liquid ceramic slurry is jetted in layers onto a build plate, with or without a separate jet that dispenses a non-ceramic support material.

[0019] The measurement of the dentition data can be performed using a CT scanner, an intraoral scanner, a coordinate measuring machine, a laser scanner, or a structured light digitizer. The measurement of the dentition data can be performed by performing a 3D scan on a cast or 3D printed tooth model. The photopolymerizable material can be selected from the group consisting of high strength oxide, nitride, carbide ceramics, and metals including but not limited to aluminum oxide (Al2O3), zirconium oxide (ZrO2), alumina toughened zirconia (ATZ), zirconia toughened alumina (ZTA), lithium disilicate, leucite silicate, and silicon nitride, as well as metals such as stainless steel 17-4PH or 316L, titanium (Ti / Ti-Al6-V4), cobalt chromium (CoCr), tungsten and tungsten carbide / cobalt (W or WC / Co), silicon carbide (SiC), molybdenum (Mo), and precious metals (e.g., gold (Au)).

[0020] Directly creating a tube by layer manufacturing may further include an apparatus including a vat including a horizontal bottom formed at least partially transparent or translucent that can be filled with a photopolymerizable material, a horizontal build platform adapted to be held at a settable height above the vat bottom, an exposure unit including a light source improved by micromirrors to more precisely control the curing, adapted to control the position and selective exposure of a surface on the build platform with an intensity pattern having a predetermined geometry, and a control unit adapted to polymerize overlapping layers on the build platform in successive exposure steps, controlling the exposure unit to selectively expose the photoreactive slurry in the vat, adjusting the relative position of the build platform with respect to the vat bottom after each exposure of a layer, and successively building up a tube with a desired shape resulting from the geometry of the successive layers.

[0021] The exposure unit further includes a laser as a light source, the light beam of which can be continuously scanned over the exposure area via a movable mirror controlled by the control unit.

[0022] The scanning accuracy may be less than 0.02 mm. The manufacturing accuracy may be from 1 μm to about 60 μm, and this accuracy may be achieved by using a layer-to-layer summation error compensation method that predicts the amount of polymerization shrinkage. The manufactured layers of the tube include materials selected from the group consisting of high strength oxide, nitride, and carbide ceramics, as well as metals including, but not limited to, aluminum oxide (Al2O3), zirconium oxide (ZrO2), alumina-toughened zirconia (ATZ), zirconia-toughened alumina (ZTA), lithium disilicate, leucite silicate, and silicon nitride, as well as metals such as stainless steel 17-4PH or 316L, titanium (Ti / Ti-Al6-V4), cobalt chromium (CoCr), tungsten and tungsten carbide / cobalt (W or WC / Co), silicon carbide (SiC), molybdenum (Mo), and precious metals, e.g., gold (Au).

[0023] The 3D CAD model can be saved as a .stl file or as a separate 3D vector file. The thickness of the produced layers varies from 5 to 100 micrometers (μm) and the machine uses an XY pixel resolution of 1 to 100 μm. Different hardening strategies (CS) and hardening depths (Cd) can be used. The choice of materials for creating the layers of the tube can be made based on the different force demands.

[0024] The printed tubes may have metal inserts that contact the archwire in the slot. The printed tubes are either a traditional twin design or modified to be self-ligating or active ligating and are designed to accommodate 0.018" to 0.022" archwires in the slots, although the slot height may vary from 0.017" to 0.023". The slot location relative to the teeth can be customized by fabricating a custom base or by fabricating a custom slot location where the base is not modified.

[0025] The minimum length of the tube from pad to slot depth can be 0.2mm to 3mm depending on the required tube offset and the desire for a smaller tube profile for patient comfort. The tube angle, offset, torque, and prescription can be determined based on the treatment selected. The structural characteristics of the tube (at any location) can be modified to facilitate easier tube peeling after treatment. Portions of the tube may be preformed green ceramic bodies, which serve to reduce the time and complexity of printed tubes.

[0026] The printed tube guide may have a single tube attachment for a single tube. An adhesive material may be used to hold the tubes on the ceramic archwire. The adhesive material may be a sticky wax. The placement of the indirect bond / custom tubes may be via a tray (e.g., silicone-based or vacuum-formed tray) that carries the custom ceramic tubes to the ideal tooth positions. The method may further include creating a tube guide that includes a rigid ceramic rectangular archwire or other arch shape that defines the location of each tube on the teeth in every plane, including at least two occlusal / incisal supports adapted to help place the tubes via the indirect bond system. The portion of the tube that holds or connects the tubes to the tooth surface may be designed based on the tooth surface profile.

[0027] The tube may have a color that matches the color of the tooth to which it is attached. The tube may be clear. The tube may have a color that is selected independent of the color of the tooth to which it is attached. In some embodiments, the 3D CAD tube structure model may include data defining at least one slot adapted to receive an archwire, including data defining a compensation angle for the walls of the slot to compensate for shrinkage due to overpolymerization and to achieve parallel slot walls. In some embodiments, the 3D CAD tube structural model can include data defining a contour of the surface of the base of the tube. The contour can be adapted to the shape of the tooth to which the tube is bonded. The contour can be further adapted based on at least one of the in / out and offset of the tube, the tip of the slot, and the torque.

[0028] In some embodiments, the 3D CAD tube structure model includes data defining a ridge on a circumferential surface of the tube structure base. The ridge can be located at the interface between the base of the tube structure and the surface of the tube structure. The ridge can be located at the gingival edge surface of the tube structure, the occlusal edge surface of the tube structure, or both. The height of the ridge can vary along the mesial / distal axis of the tube structure. The height of the ridge can be from about 0.04 mm to about 1 mm. The height of the gingival ridge can be different from the height of the occlusal ridge. The 3D CAD tube structure model can include data defining a gap in the ridge corresponding to the location of a stress riser.

[0029] In some embodiments, the 3D CAD tube structure model includes data defining a chamfer at the base of the tube structure. The chamfer can be located at the interface of the tube structure with the tooth. The chamfer can be located at the interface of the gingival tube with the tooth, the interface of the occlusal tube with the tooth, or both. The chamfer can be configured to mate with an orthodontic appliance. In some embodiments, the 3D CAD tube structure model can include data defining a fracture groove at the base or face of the tube (auxiliary slot or vertical slot). The fracture groove can be adapted to fracture upon application of a normal force.

[0030] The normal force may be applied in at least one of the following directions: mesial-distal, occlusal-gingival, or at any opposing angle. The fracture groove is configured to provide predictable fracture of the tube when a normal force is applied, allowing the tube to be peeled off by a combination of tension and peel forces. The combination of tension and peel forces may be less than the shear bond strength of the bonded tube. The normal force may be 10-180 Newtons.

[0031] The fracture groove may be in the central vertical third of the tube defined by the tube dimensions or base dimensions if they are not the same. The edges of the fracture groove are smooth to prevent intraoral debris capture. The fracture groove may include a weakened area that includes a curved indentation of the tooth in the occlusal-gingival or mesial-distal direction that culminates in a pointed tip. This pointed tip helps to increase the reliability of the fracture. The fracture groove may match the tooth contour in that portion of the tube positioning.

[0032] The fracture groove may have a constant depth from the tooth surface. The depth of the fracture groove is equal to or greater than 0.10 mm and equal to or less than 1.2 mm, calculated based on the entry and exit of the tube. The fracture groove may have a variable depth from the tooth surface. The variation in the depth of the fracture groove may be up to 50% of the distance from the tooth surface to the deepest part of the fracture groove. The width of the fracture groove may be between 0.25 mm and 1.25 mm.

[0033] In some embodiments, the 3D CAD tube structural model may include data defining at least some corners of the tube as rounded. Both gingival and occlusal corners of the tube may be rounded. The rounded corners of the tube may have a radius of curvature between 0.05 mm and 2.0 mm. The rounding may be symmetrical or asymmetrical.

[0034] In some embodiments, the 3D CAD tube structure model can include data defining a plurality of retention structures at the base of the tube. Each retention structure can be a three-dimensional shape having a positive draft angle greater than 0°. Each retention structure can be a three-dimensional shape selected from a group of three-dimensional shapes including a half-moon cone, a full cone, a square, a rectangle, a retention grid, and / or a mesh. Each retention structure has a generally trapezoidal cross section, has a midplane oriented toward the tooth structure or surface, and is wider than a base plane oriented toward the tube body. Each midplane can be flat.

[0035] Each neutral surface may be parallel to the base surface. At least some of the neutral surfaces may be non-parallel to the base surface. At least some of the neutral surfaces may be non-parallel to the base surface such that the overall pattern of the retention structure generally follows the contour of the tooth surface to which it is bonded. At least some of the neutral surfaces may be contoured to the shape of the tooth surface to which it is bonded.

[0036] In some embodiments, the tubes may be adapted to be bonded to the lingual or labial surface of the teeth. The labial or lingual tubes are made of aluminum oxide (Al2O3), zirconium oxide (ZrO2), alumina toughened zirconia (ATZ), zirconia toughened alumina (ZTA), lithium disilicate, leucite silicate and silicon nitride, as well as metals such as stainless steel 17-4PH or 316L, titanium (Ti / Ti-Al6-V4), cobalt chromium (CoCr), tungsten and tungsten carbide / cobalt (W or WC / Co), silicon carbide (SiC), molybdenum (Mo) and precious metals (e.g., gold (Au)).

[0037] The 3D CAD tube structural model may include data defining a mesial-distal or horizontal slot adapted to receive an archwire, a vertical slot adapted to receive at least a portion of the archwire within the central third of the tube, or both. The vertical slot may be further adapted to receive a digitally designed lingual multi-loop wire.

[0038] Some embodiments provide a method of manufacturing a customized orthodontic tube for a patient, the method including: obtaining a three-dimensional (3D) model of one or more dentitions of the patient; generating a 3D model of an orthodontic tube structure using the 3D model of the one or more dentitions of the patient, the orthodontic tube structure including a release structure that facilitates release of the orthodontic tube from the patient's teeth; and using an additive manufacturing device to create the customized orthodontic tube based on the 3D model of the orthodontic tube structure.

[0039] In some embodiments, at least a portion of the release structure has a customized shape based on a 3D model of at least one of the one or more dentitions. In some embodiments, the release structure includes a stress concentrator on a portion of the orthodontic tube structure. In some embodiments, the stress concentrator is shaped such that the customized orthodontic tube fractures when a normal force is applied to the stress concentrator. In some embodiments, the stress concentrator extends along an occlusal-gingival direction of the orthodontic tube structure. In some embodiments, the stress concentrator includes a portion with a profile that is substantially triangular in cross section.

[0040] In some embodiments, the release structure comprises a ridge in the 3D model of the orthodontic tube structure. In some embodiments, the ridge is proximate to the interface between the base of the orthodontic tube structure and the face of the orthodontic tube structure. In some embodiments, the height of the ridge varies along the mesial-distal axis of the orthodontic tube structure.

[0041] Some embodiments provide a customized orthodontic tube created by an additive manufacturing device using a 3D model of an orthodontic tube structure generated using a 3D model of one or more dentitions of a patient, the customized orthodontic tube including a release structure that facilitates release of the customized orthodontic tube from the patient's teeth.

[0042] In some embodiments, at least a portion of the release structure has a customized shape based on a 3D model of at least one of the one or more dentitions. In some embodiments, the release structure includes a stress concentrator in a portion of the customized orthodontic tube. In some embodiments, the customized orthodontic tube fractures when a normal force is applied to the stress concentrator.

[0043] In some embodiments, the customized orthodontic tube comprises: a base; and two portions; wherein the stress concentrator comprises a generally V-shaped space between the two portions; and an apex of the generally V-shaped space is proximate to the base. In some embodiments, each of the two portions comprises a substantially flat wall on each side of the generally V-shaped space.

[0044] In some embodiments, the release structure comprises at least one ridge. In some embodiments, the customized orthodontic tube further comprises a base; and a face perpendicular to the base; and the at least one ridge is located at least partially near an intersection of the base and the face. In some embodiments, the face includes a slot opening sized to allow an archwire to be inserted into the slot.

[0045] In some embodiments, the customized orthodontic tube comprises two sections separated at least in part by a space, and the at least one ridge comprises a first ridge and a second ridge, the first ridge being located in the first of the two sections; and the second ridge being located in the second of the two sections. In some embodiments, the space separating the two sections is a stress concentrator.

[0046] In some embodiments, the customized orthodontic tube includes a plurality of sections, each of which includes a respective slot extending therethrough, the slots of the plurality of sections being aligned such that an archwire passes through the slots of the plurality of sections.

[0047] Some embodiments provide a method of manufacturing a customized orthodontic tube for a patient, the method including: obtaining a three-dimensional (3D) model of one or more dentitions of the patient; generating a 3D model of an orthodontic tube structure using the 3D model of the one or more dentitions of the patient, the orthodontic tube structure including: a slot surrounded by a plurality of walls for receiving a wire, an end of one or more of the plurality of walls being angled relative to a mesial surface of the orthodontic tube structure; and using an additive manufacturing device to create the customized orthodontic tube based on the 3D model of the orthodontic tube structure.

[0048] In some embodiments, the method further includes determining an angle of a major portion of the slot based on an orthodontic prescription; and generating the 3D model of the orthodontic tube structure includes generating a slot having the determined angle of the major portion of the slot. In some embodiments, the orthodontic prescription includes an indication of a desired torque, tip, rotation, or combination thereof for an associated tooth of the patient's tooth.

[0049] In some embodiments, the slot includes four walls and four corners; and the slot includes a mortise at each corner of the slot to prevent polymerization of material at the corners of the slot during additive manufacturing of the customized orthodontic tube.

[0050] In some embodiments, the method further includes determining a size and shape of the slot based on a size and shape of a wire to be received in the slot; generating the 3D model of the orthodontic tube structure includes generating a slot having the determined size and shape.

[0051] In some embodiments, generating a 3D model of the orthodontic tube structure includes: determining a grayscale pattern of at least a portion of the slot, the grayscale pattern being indicative of a polymerization pattern to be applied by the additive manufacturing device; and applying the grayscale pattern to at least a portion of the slot.

[0052] In some embodiments, the grayscale pattern includes a plurality of pixels, each pixel indicating an amount of material polymerized at a respective location within the 3D model of the orthodontic tube structure. In some embodiments, the grayscale pattern includes a plurality of pixels indicating whether polymerization is on or off at a respective location within the 3D model of the orthodontic tube structure.

[0053] In some embodiments, the orthodontic tube structure includes a notch through which material flowing through the slot can exit the orthodontic tube structure. In some embodiments, the orthodontic tube structure includes an interface adjacent to a build plate where the customized orthodontic tube is created; and the notch is located at least in part at the interface adjacent to the build plate.

[0054] Some embodiments provide a customized orthodontic tube created by an additive manufacturing device using a 3D model of an orthodontic tube structure generated using a 3D model of one or more dentitions of a patient, the customized orthodontic tube including: a slot surrounded by a plurality of walls for receiving a wire, the slot having an end of one or more of the plurality of walls at an angle relative to a mesial surface of the customized orthodontic tube.

[0055] In some embodiments, the angle of the main portion of the slot is based on the orthodontic prescription. In some embodiments, the slot is shaped based on the shape of the wire to be received by the slot. In some embodiments, the customized orthodontic tube further includes a notch that allows material to flow through the notch and out of the slot when the customized orthodontic tube is connected to the base plate.

[0056] In some embodiments, the customized orthodontic tube further includes two portions, each having a respective slot extending therethrough. In some embodiments, each slot of the two portions includes: a first side where the ends of one or more slot walls are angled; and a second side where the ends of one or more slot walls are not angled. In some embodiments, the slots of the two portions are aligned such that the angle of a major portion of the first slot is the same as the angle of a major portion of the second slot.

[0057] In some embodiments, the slot is shaped to receive a generally rectangular wire. In some embodiments, at least some of the walls are substantially parallel to one another. In some embodiments, ends of one or more walls are each angled between about 20 degrees and 80 degrees from a mesial surface of the customized orthodontic tube.

[0058] Some embodiments provide a method of manufacturing a customized orthodontic tube for a patient, the method including: obtaining a three-dimensional (3D) model of one or more dentitions of the patient; generating a 3D model of an orthodontic tube structure using the 3D model of the one or more dentitions of the patient, the orthodontic tube structure including a curved gingival base edge; and fabricating the customized orthodontic tube based on the 3D model of the orthodontic tube structure using an additive manufacturing device.

[0059] In some embodiments, the method further comprises determining a radius of curvature of a corner of the curved gingival base edge, and generating the 3D model of the orthodontic tube structure comprises generating the curved gingival base edge having a corner of the determined radius of curvature. In some embodiments, determining the radius of curvature of the corner of the curved gingival base edge comprises determining the radius of curvature based on a 3D model of a tooth of the one or more dentitions.

[0060] In some embodiments, determining the radius of curvature based on a 3D model of the tooth comprises determining the radius of curvature based on a gingival margin of the tooth. In some embodiments, determining the radius of curvature of the corner of the curved gingival base edge comprises determining the radius of curvature based on an orthodontic prescription.

[0061] In some embodiments, the orthodontic prescription includes torque, tip, rotation, or combination thereof instructions. In some embodiments, the radius of curvature of the corner of the curved gingival base edge is between about 0.05 mm and 2.0 mm. In some embodiments, the orthodontic tube structure includes a curved occlusal edge. In some embodiments, the orthodontic tube structure includes an angled hook.

[0062] In some embodiments, the method further comprises determining an angle of the angled hook, and generating the 3D model of the orthodontic tube structure comprises generating an angled hook having the determined angle. In some embodiments, the angled hook is angled between 0 degrees and 90 degrees labially from the plane of the orthodontic tube structure. In some embodiments, the angled hook is angled between 0 degrees and 90 degrees facially from the plane of the orthodontic tube structure. In some embodiments, the angled hook is angled between 0 degrees and 45 degrees from the body of the orthodontic tube structure in the plane of the angled hook.

[0063] In some embodiments, a customized orthodontic tube is provided that is manufactured by an additive manufacturing device using a 3D model of an orthodontic tube structure that is generated using a 3D model of one or more dentitions of a patient, the customized orthodontic tube comprising: a curved gingival base edge. In some embodiments, the customized orthodontic tube further comprises a curved occlusal edge. In some embodiments, the curvature of the curved gingival edge is based on a gingival margin of a tooth of one or more dentitions. In some embodiments, the curvature of the curved gingival edge is based on an orthodontic prescription. In some embodiments, the radius of curvature of the corner of the curved gingival base edge is between about 0.05 mm and 2.0 mm.

[0064] In some embodiments, the customized orthodontic tube further comprises an angled hook, hi some embodiments, the angled hook is angled relative to a body of the customized orthodontic tube to avoid the angled hook contacting a portion of the patient's mouth. There has thus been outlined, rather broadly, the features of the disclosed subject matter in order that the detailed description that follows may be better understood, and in order that the present contributions to the art may be better appreciated. There are, of course, additional features of the disclosed subject matter that will be described below and which form the subject matter of the claims appended hereto. It is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. [Brief description of the drawings]

[0065] Various aspects and embodiments are described with reference to the following figures, in which it should be understood that the figures are not necessarily drawn to scale, and in which each of the identical or nearly identical components shown in the various figures are represented by a similar numeral, and for purposes of clarity, not every element is labeled in every figure.

[0066] [Figure 1]FIG. 1 shows an exemplary process flow chart of a direct manufacturing process for lingual or labial orthodontic tubes by ceramic slurry-based AM according to some embodiments of the technology described herein. [Diagram 2] FIG. 2 shows an example of an orthodontic tube connected to a tooth surface according to some embodiments of the technology described herein. [Figure 3A] FIG. 3A shows a mesial view of an exemplary orthodontic tube, according to some embodiments of the techniques described herein. [Figure 3B] FIG. 3B shows a distal view of the exemplary orthodontic tube of FIG. 3A, according to some embodiments of the techniques described herein. [Figure 4A] FIG. 4A shows a diagram of an exemplary orthodontic tube including a stress concentrator, in accordance with some embodiments of the techniques described herein. [Figure 4B] FIG. 4B shows a diagram of an exemplary orthodontic tube including a stress concentrator, according to some embodiments of the techniques described herein.

[0067] [Figure 4C] FIG. 4C shows an orthodontic tube with a curved gingival edge to approximate the gingival margin of a patient's teeth, according to some embodiments of the techniques described herein. [Figure 4D] FIG. 4D shows an orthodontic tube with curved occlusal edges to approximate the occlusal surfaces of a patient's teeth, according to some embodiments of the techniques described herein. [Diagram 5] FIG. 5 shows an exemplary orthodontic tube from the perspective of the tube, according to some embodiments of the technology described herein. [Figure 6] FIG. 6 shows a cross-sectional view of an exemplary orthodontic tube including a fracture groove according to some embodiments of the technology described herein. [Figure 7] FIG. 7 shows a cross-sectional view of an exemplary orthodontic tube including fracture grooves having variable depths, according to some embodiments of the technology described herein.

[0068] [Figure 8] FIG. 8 shows an exemplary orthodontic tube with a fractured wall, according to some embodiments of the technology described herein. [Figure 9] FIG. 9 shows an exemplary orthodontic tube with a retention structure according to some embodiments of the technology described herein. [Figure 10] FIG. 10 shows a cross-sectional view of an exemplary retention structure in accordance with some embodiments of the technology described herein. [Figure 11] FIG. 11 shows a cross-sectional view of an exemplary orthodontic tube on a tooth in accordance with some embodiments of the techniques described herein. [Figure 12A] FIG. 12A shows a view of the gingival or occlusal surface of an exemplary orthodontic tube, according to some embodiments of the technology described herein. [Figure 12B] FIG. 12B shows a buccal view of an exemplary orthodontic tube, according to some embodiments of the technology described herein. [Figure 12C] FIG. 12C shows a mesial or distal view of an exemplary orthodontic tube, according to some embodiments of the technology described herein.

[0069] [Figure 13A] FIG. 13A illustrates an exemplary orthodontic tube including a ridge defined around at least a portion of the circumference of the tube base, according to some embodiments of the technology described herein. [Figure 13B] FIG. 13B shows an exemplary orthodontic tube including a split slot body according to some embodiments of the technology described herein. [Figure 14] FIG. 14 shows an example of an orthodontic tube having a chamfer around the circumference of the base of the tube, according to some embodiments of the technology described herein. [Figure 15A] FIG. 15A shows a diagram of polymerized pixels in accordance with some embodiments of the techniques described herein. [Figure 15B]FIG. 15B shows a grayscale pattern for pixel polymerization according to some embodiments of the techniques described herein.

[0070] [Figure 16A] FIG. 16A shows an exemplary orthodontic tube slot, according to some embodiments of the technology described herein. [Figure 16B] FIG. 16B shows an exemplary orthodontic tube slot manufactured by alternating on and off pixels along the edge of the slot, according to some embodiments of the techniques described herein. [Figure 17] FIG. 17 illustrates an exemplary computer system in accordance with some embodiments of the techniques described herein. [Figure 18] FIG. 18 shows an example of an orthodontic tube on a base plate according to some embodiments of the technology described herein. [Figure 19] FIG. 19 illustrates an exemplary orthodontic tube with a stress concentrator, according to some embodiments of the technology described herein. [Figure 20] FIG. 20 shows a gingival ridge or portion thereof according to some embodiments of the techniques described herein. [Figure 21] FIG. 21 shows a flow chart of an exemplary process for manufacturing embodiments of the orthodontic tubes described herein, in accordance with some embodiments of the technology described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0071] Some embodiments of the present invention provide improved techniques for creating custom lingual or labial orthodontic tubes and provide the ability to manufacture such tubes in-house. Lingual or labial orthodontic tubes are sometimes referred to herein as "orthodontic tubes" or "tubes."

[0072] The inventors have recognized that conventional orthodontic tubes may not be reliably peeled off of a patient's teeth and are therefore difficult to remove from the patient's teeth. As such, conventional orthodontic tubes may require a clinician (e.g., an orthodontist) to apply significant force or otherwise manipulate the orthodontic tube from the patient's teeth. This makes treatment more difficult for the clinician while also increasing discomfort for the patient during treatment.

[0073] Therefore, the present inventors have developed a customized orthodontic tube and a manufacturing technique thereof, which includes a release structure that can reliably release the orthodontic tube from the teeth. The release structure allows a clinician to apply a certain amount of force at a specific location in the orthodontic tube to reliably release the orthodontic tube from the patient's teeth.

[0074] In some embodiments, the release structure may include stress concentrations that cause the orthodontic tube to break as a result of a force applied to a particular location within the orthodontic tube, hi some embodiments, the release structure may include ridges that allow a clinician to peel the orthodontic tube by applying force to the ridges (e.g., using pliers).

[0075] The inventors have further developed customized orthodontic tubes with slots shaped to facilitate orthodontic treatment, and techniques for manufacturing customized orthodontic tubes that can shape the slots to facilitate orthodontic treatment. In some embodiments, the slots may include angled or chamfered wall ends that facilitate the clinician's insertion of a wire into the slot.

[0076] In some embodiments, the slots may have customized slot angles to provide a desired force for orthodontic treatment. For example, the slot angles of the orthodontic tubes can be customized to apply forces based on an orthodontic prescription indicating the desired movement (e.g., torque, tip, rotation, or a combination thereof) to be applied to the patient's teeth.

[0077] The inventors have further developed an AM technique for orthodontic tubes that creates orthodontic tubes that more accurately match the dimensions of a 3D model of the orthodontic tube structure. In some embodiments, the technique determines a grayscale pattern of portions (e.g., pixels) of slots in a 3D model of the orthodontic tube structure. The grayscale pattern is indicative of the polymerization pattern that is applied by the AM device to locations within the orthodontic tube during manufacturing. For example, the grayscale pattern may indicate that polymerization is off in certain locations and on in other locations.

[0078] In another example, the grayscale pattern may show variations in intensity of polymerization across portions of the slot. The grayscale pattern may result in a manufactured orthodontic tube that more closely matches the 3D model of the orthodontic tube structure used in the AM. In some embodiments, the technique places mortises at the corners of the slots in the 3D model of the orthodontic tube structure. The mortises may represent locations where polymerization of the AM device is stopped. The mortises in the 3D model of the orthodontic tube structure may reduce corner rounding of the orthodontic tube created by AM.

[0079] The inventors have developed an orthodontic tube that facilitates post-processing of the orthodontic tube after AM. After fabricating the orthodontic tube with an AM device, it may be necessary to clean the orthodontic tube. For example, a cleaning agent may be applied to the orthodontic tube to remove excess non-polymerized material. Thus, the inventors have developed an orthodontic tube that includes a notch that facilitates cleaning of the orthodontic tube. The notch allows material in the slot of the orthodontic tube to flow out of the notch while the orthodontic tube is attached to a base plate fabricated by the AM device.

[0080] The inventors have further developed an orthodontic tube and a technique for its manufacture that reduces discomfort of the orthodontic tube in a patient's mouth. In some embodiments, the technique creates an orthodontic tube with a curved gingival edge and / or occlusal base edge. The curved gingival and / or occlusal base edge allows the orthodontic tube to be placed closer to the patient's gums while reducing discomfort to the patient by aligning more closely with the patient's gum line. In some embodiments, the technique creates an orthodontic tube with an angled hook, thereby preventing the hook from contacting parts of the patient's mouth (e.g., gums and / or cheeks) to reduce discomfort to the patient when the orthodontic tube is placed in the patient's mouth.

[0081] An exemplary flow chart of an embodiment of a direct manufacturing process 100 for lingual or labial orthodontic tubes by ceramic slurry-based AM is shown in FIG. 1. The process begins at 102, where dentition data is measured and parameters of the tooth profile are analyzed. For example, such measurements may involve CT layers directly scanning the patient's teeth with a non-contact 3D or intraoral scanner, or may involve 3D readings of pre-cast or 3D printed tooth models using a coordinate measuring machine, laser scanner, or structured light digitizer. The scanning accuracy of such techniques is typically less than 0.02 mm.

[0082] At 104, based on the given dentition data, a 3D CAD model of the measured teeth is constructed based on the dentition data and saved in the computer in a typical file format such as stl, additive manufacturing file (AMF) format, or other 3D vector file. The external structure of teeth is complex and usually contains irregular curves. Software can then be used to reposition the teeth in the model to match the desired treatment outcome based on the long axis of the teeth.

[0083] The tube pads that hold or connect the tubes to the tooth surface can be specially designed according to the profile of the tooth surface rather than a generic grid pattern. Customized tubes can meet the needs of individual cases, such as increased anterior labial crown torque required in certain types of cases. Figure 2 shows an example of an orthodontic tube connected to a tooth surface according to some embodiments of the technology described herein.

[0084] 2, for the curvature of tooth surface 206, the designed tube pad (tooth side of the tube) is conformed to the lingual or labial surface of the tooth, as shown for lingual tube 202 and labial tube 204. In this example, tube 202 (or 204 herein) has a base surface 208 that is contoured to the shape of tooth 206, such as along tube / tooth interface 210.

[0085] The base surface contour 208 can be configured to match the desired location of the tube 202 on the tooth. Changing the location of the tube may require changing the contour 208. The base 208 can be formed to the contour of the tooth while the tube face and slot 212 can be aligned to a pre-prescribed location that includes variables typically considered in prescribing orthodontic tubes including, for example, 1) in / out and offset, 2) tip, 3) torque, etc. For example, the in / out location and offset may involve the thickness and offset of the tube relative to the tooth along the tube / tooth interface 210.

[0086] Tip parameters may include the angle of the slot 212 along the proximal-distal direction. Torque parameters may include the inclination of the slot 212 and / or base 208 relative to the tooth surface as torque is applied by the archwire. The tube 300 can accommodate clinical torque values ​​ranging from 0° to -45°, and in case of extreme torque, the tube can be adjusted internally while maintaining the same basic shape.

[0087] Additional information is then entered at 106, such as the desired torque, offset, angulation of the selected tube, and occlusal / incisal coverage of the placement guide. At 108, the software designs a tube (or multiple tubes) based on the input 3D CAD model of the measured teeth, a model of the desired treatment outcome, and any additional information entered. The output of the design process may be a 3D CAD model. Such a 3D CAD model may be designed for a single lingual / labial tube structure, including tube guides and tube pads that contact the tooth surfaces, as well as slots that provide ideal positioning depending on the orthodontic requirements, ceramic tube material, and tooth profile.

[0088] The tube pad (bonding pad) may be less than 0.4 mm thick from the tooth. A tube placement guide may be placed on the occlusal / incisal side to guide correct placement of the tube on the tooth. Tube materials include powders of high strength oxide ceramics such as aluminum oxide (Al2O3) and zirconium oxide (ZrO2), other high strength ceramic compositions, and metals.

[0089] The 3D CAD tube structural model is processed to generate manufacturing control data for use in the production facility. For example, when a ceramic slurry-based AM device is used to create a tube, the software slices and separates the 3D CAD tube structural model into thin layers to obtain a horizontal cross-sectional model for each layer. Based on this cross-sectional model, the DLP device can directly create the ceramic tube, ensuring that the shape of each layer matches the 3D CAD structural data. For example, the thickness of such a layer can be about 20 μm to about 50 μm (micrometers or microns) with a manufacturing accuracy of about 1 μm to about 10 μm by using inter-layer additive error compensation.

[0090] Returning to 108 in FIG. 1, the 3D CAD tube structural model is sent or imported into a 3D fabrication machine, such as a ceramic slurry-based AM machine, to create the ceramic tube.

[0091] DLP is another ceramic additive manufacturing (AM) process that works by stacking layers of photocurable resin and ceramic oxides such as aluminum oxide (Al2O3) or zirconium oxide (ZrO2), nitrides or silicates solid fillers, followed by thermal debinding and sintering steps. The higher resolution of this process is made possible by the LED-lit Digital Mirror Device (DMD) chip and the optics used. (Stereo)lithography-based ceramic manufacturing (LCM) has improved this process, resulting in a more precise process with higher resolution (40μm) and stiffness.

[0092] The LCM process involves the selective curing of photosensitive resins containing uniformly distributed oxide or glass-ceramic particles and can be produced with very high resolution by imaging systems; lasers can also be used for the photopolymerization, but the transfer of layer information is possible with LED technology, which is constantly improving.

[0093] The base of the tube is bonded to the tooth surface and the slot in the tube fits the archwire. Depending on the mechanical property requirements, layers may require different material compositions during the DLP manufacturing process. After assembly and processing, the tube may be graded to improve performance.

[0094] Post-processing can then be applied at 110. For example, heat treatment (to burn out the binder) and sintering processes can be applied to achieve optimal or improved ceramic density. For example, the debinding and sintering steps may include removing the green tube from the device, exposing the blank to a furnace to decompose the polymerized binder (debinding), and sintering the ceramic material.

[0095] In another example, a cleaning or flushing process may need to be performed to remove any uncured or excess material. The cleaning or flushing process can be performed when connecting the tube to the build plate, prior to debinding and sintering. To accommodate such a process, the tube 300 of FIG. 3A and the tube 400 of FIG. 4A may have a small notch 408 on the mesial side, as shown in FIG. 4, to allow material (e.g., cleaning fluid or air) to flow out of the slot during fabrication while still expressing the wire torque sufficiently.

[0096] The notch 408 may have a width between 0.1 and 1.5 mm and a height of 0.1 to 1 mm. The notch 408 may extend through a slot from any exterior surface of the tube. As shown in FIG. 3, the mesial side of the face of the tube includes three edges that are flat or substantially flat and includes a fourth edge (i.e., notch 408) that is configured to be removably connected to a build plate and fabricated on the buccal surface of the tube. The notch 408 defined in the buccal surface of the tube may be trapezoidal, substantially trapezoidal, square, substantially square, rectangular, substantially rectangular, substantially, elliptical, or substantially elliptical in shape. In the case of a trapezoidal or substantially trapezoidal shape, the non-parallel sides of the notch 408 may have a stepped profile.

[0097] The ratio of the notch 408 to the slot width can be between 25% and 200%. In some embodiments, the ratio is about 25%, 50%, 75%, 100%, 125%, 150% or 200%. For example, the parallel sides can be about 100% of the slot width and the non-parallel sides can be about 25% or 50%. FIG. 18 illustrates an exemplary orthodontic tube 1800 on a base plate 1804 according to some embodiments of the techniques described herein. For example, the orthodontic tube 1800 may be obtained by AM using a 3D model of the orthodontic tube structure. The orthodontic tube 1800 may be created by an AM device in a series of layers starting with the layer closest to the base plate 1804 as indicated by the "print direction" arrow in FIG. 18. As shown in FIG. 18, the orthodontic tube 1800 includes a notch 1802 in the orthodontic tube 1800 adjacent to a build play 1804. The notch 1802 may allow material in the slot 1806 to flow out of the orthodontic tube 1800. For example, after fabrication, the orthodontic tube 1800 may be attached to the base plate 1804. Material (e.g., cleaning solution, air, and / or other material) may be applied to the orthodontic tube 1800. The notch 1802 can provide an opening through which material can flow out of the slot 1806 .

[0098] In addition, the tube surface can be treated based on clinical requirements. At 112, the tube is ready to be placed. Typically, the thickness of the tube pad can be less than 1 mm for lingual tubes and less than 1.5 mm for labial tubes. Suitable materials of manufacture include high strength oxide, nitride, and carbide ceramics and metals including, but not limited to, aluminum oxide (Al2O3), zirconium oxide (ZrO2), alumina toughened zirconia (ATZ), zirconia toughened alumina (ZTA), lithium disilicate, leucite silicate, and silicon nitride, as well as metals such as stainless steel 17-4PH or 316L, titanium (Ti / Ti-Al6-V4), cobalt chromium (CoCr), tungsten and tungsten carbide / cobalt (W or WC / Co), silicon carbide (SiC), molybdenum (Mo), and precious metals (e.g., gold (Au)).

[0099] The tube pads may be bonded to the tooth surface using well-known dental adhesives. The slots in the tubes fit the archwire and can be straight or custom bent. Depending on the manufacturing process used, the layers may require different ceramic or powder compositions. For example, if a selective laser melting manufacturing process is used, an LED light source may be used to selectively cure a photosensitive resin containing oxide or glass ceramic particles. Different ceramic or powder compositions may be used for different layers.

[0100] End views of an exemplary print tube 300 are shown in Figures 3A (mesial view) and 3b (distal view). In Figure 3a, the base 306 of the tube is shown on the right (buccal side of the tube) and the face 304 of the tube is shown on the left (lingual side of the tube). The pad 308 is the portion that contacts the teeth, and the face 304 includes a first tube body 316 that defines a first slot 301, which in some embodiments may be a mesial-distal slot adapted to receive an archwire for applying force to the teeth. The tube 300 may have an occlusal-gingival distance of 1.4mm to 5mm and a mesial-distal distance of 2mm to 8mm. The tube 300 has a filleted edge 312 with a radius between 0.05mm and 1mm to prevent irritation of the cheek or gingival tissue. The fillet edge 312 may be formed on the base 306 and / or the first tube body 316. The first tube body 316 may include a hook 320.

[0101] The slot 301 can have a desired slot wall location 302 and a compensation angle 303 of the walls of the slot 301 that can be utilized to combat shrinkage due to overpolymerization and achieve the desired dimension of parallel slot walls 302. In some embodiments, the slot 301 can be a mesial-distal slot adapted to receive an archwire for applying force to the teeth. The slot 301 can be initially manufactured to have a "dovetail" cross-section that includes the compensation angle 303 so that the finished tube can achieve the desired dimension of parallel slot walls as indicated by the desired slot wall location 302.

[0102] In some embodiments, the dovetail includes a mortise 324 defined at each corner of the slot 301. The slot 324 may include four walls and four corners. The slot may include a mortise at each corner of the slot. The mortise may indicate an area in the 3D model of the orthodontic tube structure where the AM device prevents polymerization of material. Thus, the mortise may prevent material from polymerizing at the corners of the slot during AM of the orthodontic tube. In some embodiments, the polymerization location in the 3D model may be specified by a pixel. In such an embodiment, the AM device may stop polymerization of material at a pixel corresponding to the mortise in the 3D model. For example, the mortise 324 may be formed by turning off a pixel of a digital micromirror device in a DLP system such that material does not polymerize at the pixel location. The mortise reduces overpolymerization of material, which may result in improved accuracy of the orthodontic tube created by AM. The mortise may result in less rounded corners of the slot.

[0103] In some embodiments, the slot 301 may be sized and shaped based on the size and shape of the wire to be received by the slot 301. A 3D model of the orthodontic tube structure may be generated with a slot of a predetermined size and shape. For example, the slot 301 on the tube is designed to accommodate a rectangular wire when fully filled with high precision of size, shape, and angle, and with a thin thickness. In some embodiments, the slot 301 may be manufactured to any desired size and shape. In some embodiments, the slot 301 is manufactured with a depth greater than its height or width. In some embodiments, the height of the slot may vary between 0.016 inches and 0.024 inches, and the width may be between 0.020 inches and 0.035 inches.

[0104] In some embodiments, the mesial and distal ends of the slot may be chamfered 310 to facilitate insertion of an orthodontic wire. In some embodiments, the angle of the chamfer 310 may be between 20° and 80° from the mesial surface. A chamfered slot may include a slot surrounded by a wall, with the end of the wall at an angle relative to the mesial surface of the tube. In some embodiments, the chamfered slot may facilitate insertion of a wire into the slot. The chamfered slot may reduce forces resisting insertion of a wire through the slot. In some embodiments, the end of one wall of the slot may be chamfered at a different angle than the end of another wall of the slot. In some embodiments, the ends of all walls of the slot may be approximately the same.

[0105] In some embodiments, the tube base 306 may have different heights depending on the material selected or the orthodontic result desired. Similarly, the tube pad 308 may be highly conformable to the tooth surface and maximize the tooth contact surface. This may allow the clinician to place the tube more accurately and bond it better to the tooth. Also, each slot has a unique position and shape to cooperate with the archwire, minimizing twist errors and achieving improved orthodontic results. In many embodiments, these features may be manufactured as a single piece and customization of the slot to the tooth may be a function of repositioning the slot or moving the tube base. In many embodiments, it is not necessary to machine the features to create the appropriate tube.

[0106] In some embodiments, the mesial surface of the tube 300 includes a pad 308 and a first tube body 316 connected to the pad 308. The first tube body 316 defines a slot 301, a chamfer 310 defined on the gingival, lingual and occlusal edges of the mesial surface, and a notch 408 formed on the buccal edge of the mesial surface. The pad 308 is configured to be the negative of the tooth surface. The chamfer 310 extends at an inward angle from the edge to the slot wall. A mortise 324 is formed at the intersection of adjacent slot walls. The chamfer is formed by one or more edge faces of the notch 408 extending at an inward angle relative to the slot wall. In the embodiment shown in FIG. 3A, the notch edge facing the mesial surface is chamfered and extends at an inward angle relative to the slot wall, and the non-parallel side edges of the notch 308 extend inward from the mesial surface to the notch edge facing the mesial surface. The hook 320 is connected to the first tube body 316 at the intersection of the gingival and buccal surfaces of the first tube body 316. In some embodiments, the hook 320 can be formed on the buccal surface.

[0107] As shown on the surface of the tube 400 in FIG. 4A, the tube 400 may have indicia 410 stamped into it to indicate which tooth it should be placed on. The indicia 410 may be on any surface of the tube and may range in width between 0.5 and 4 mm and in height from 0.5 to 4 mm. The indicia may be up to 1 mm deep. The indicia 410 may include any form of numbers, letters, characters, polygons, or combinations thereof. In design variations, the indicia may be raised or embossed from the surface of the tube.

[0108] The tube 400 can further include attachments such as hooks 404 that provide the ability to use additional delivery systems such as elastomers, springs, or other attachments that generate a force vector. In many embodiments, these features can be manufactured as a single piece, protruding from a pre-designed area to generate the appropriate force vector desired. The hooks 404 can be curved hooks, straight hooks, or ball hooks. The hooks 404 can have configurable custom angles to meet the patient's needs, physician prescriptions, and help avoid gum or cheek irritation. FIG. 4A illustrates this configurability via a plane 405 of the hook 404 that divides the hook into symmetrical halves.

[0109] In some embodiments, the hook 404 may be angled. For example, the hook 404 may be angled to avoid the hook 404 contacting a portion of the patient's mouth (e.g., cheek and / or gums) when the orthodontic tube is placed in the patient's mouth. A system for generating a 3D model of the orthodontic tube structure may be configured to determine the angle of the hook 404 and generate a 3D model of the orthodontic tube structure to include the determined angle of the hook. In some embodiments, the plane of the hook 405 may be angled between 90° labially and 30° lingually from the plane of the tube 400 and may be angled up to 45° in either direction from the direction of the slot. The end of the hook 404 may be angled up to 45° in the plane of the hook 405 away from the body of the tube 400. Although the tubes 300 and 400 are shown with hooks, the tubes may be formed without hooks.

[0110] The tube 400 includes a base 414 and a face 418. The base 414 includes a pad surface 422, a gingival edge 426, an occlusal edge 430, a mesial edge 434, and a distal edge 438. The face 414 defines a slot extending therethrough. The face 418 includes a split tube body including a first tube body 442 defining a first slot extending therethrough and a second tube body 446 defining a second slot extending therethrough. The pad 422 is configured to be the negative of a tooth surface. The pad 422 includes retention features as further described with reference to FIGS. 9 and 10.

[0111] The tube 400 may also include a notch 406 behind the slot at the distal end to accommodate attachment or retention of an elastomer, ligature, spring, or other accessory that generates a force vector. The notch 406 can be defined between the base and the tube body (e.g., tube body 316 or second tube body 446). The notch 406 can have a mesial-distal distance of between 0.1 mm and 1 mm and a labial-lingual dimension of between 0.2 mm and 1.5 mm. The notch 406 can extend across the occlusal-gingival extent of the tube or can be formed along only a portion of that extent, for example to form a rounded end. In some embodiments, a nub or protrusion is formed on the distal end of the second tubular body 446 to aid in the attachment or retention of an elastomer, ligature, spring or other accessory.

[0112] As shown in FIG. 4, the tube 400 includes two separate cuts made along the centerline of the tube extending occlusally / gingivally, which allows the tube to reliably fracture and delaminate when mesial / distal pressure is applied. The first 401 is cut along the base and includes a custom contoured polygon that matches the shape of the tooth, cutting consistently from the tooth surface to a maximum depth of 0.3mm. The width of this polygon is over 0.1mm and is 75% of the tube width. The second 402 is a stress concentrator cut from the front of the tube. This second cut shape has smooth edges to avoid trapping debris in the oral cavity and can be angled 0°-45° towards the mesial surface of the tube. This shape peaks to provide consistent fracture at the desired location.

[0113] Depending on the tooth morphology details, tube prescription, and desired strength, the cut 403 can begin anywhere from 0.1mm to 1.2mm from the tooth and extend the remainder of the tube structure. The final width of this cut will range from 5%-50% of the tube width. The curve of the cut 403 in the gingival / occlusal shape perfectly matches the curvature of the collinear tooth. This shape is created by a combination of thickening and Boolean operations based on the tooth distance field and its relationship to the tube. The shape location and thickness details are determined by calculating the in-out of the tube and using this value in an algorithm determined through experimental testing to provide optimal tube strength.

[0114] As described herein, in some embodiments, the orthodontic tube may include a release structure including a stress concentrator. In some embodiments, the release structure may be customized based on a 3D model of the patient's teeth. The stress concentrator may be shaped such that the orthodontic tube fractures in response to a force applied to the stress concentrator. For example, the stress concentrator may fracture in response to a normal force of 35-40 Newtons. In some embodiments, the stress concentrator may extend along an occlusal-gingival direction of the orthodontic tube. In some embodiments, the stress concentrator may include a portion having a substantially triangular cross-section.

[0115] FIG. 19 illustrates an exemplary orthodontic tube 1900 with a stress concentrator 1902, according to some embodiments of the techniques described herein. As shown in FIG. 19, the stress concentrator 1902 has a tip at a distance 1904 from the tooth surface. The stress concentrator 1902 then extends from the tip in a generally V-shape. In the example of FIG. 19, normal forces applied to both sides of the stress concentrator 1902 may cause the orthodontic tube 1902 to break and thus delaminate from the patient's tooth. In some embodiments, the distance the stress concentrator 1902 extends may be determined based on the desired size of any flat protrusions. In some embodiments, the maximum width of the stress concentrator 1902 may be determined based on the desired steepness of the walls of the stress concentrator 1902.

[0116] As shown in FIG. 4, in some embodiments, the gingival corners 407 of the tube 400 are rounded to account for keratinized / attached gingiva that may interfere with the bonding surface. The roundness and radius of these corners may vary from patient to patient and from tooth to tooth within a case. In some embodiments, the radius of curvature of the gingival corners may be determined based on a 3D model of the patient's teeth. In some embodiments, the roundness and radius of the teeth and / or placement relative to the gingival margin and / or occlusal edge are determined by the patient's prescription and / or based on the practitioner's preferences that affect the smile arc. A tube with a custom-formed edge can be placed closer to the gingival margin or occlusal edge than a stock tube with a stock base. In some embodiments, the radius of curvature of the rounded gingival corners 407 may be in the range of 0.05 mm to 2.0 mm. FIG. 4C shows a tube 400' with a gingival edge 450 curved to approximate the gingival margin 454 of a patient's tooth 458.

[0117] As shown in FIG. 4D, in some embodiments, the occlusal edge of the orthodontic tube can be curved or rounded. FIG. 4D shows a tube 400'' with an occlusal edge 462 that is curved to approximate the occlusal surface 466 of the patient's teeth. The radius of curvature of the occlusal edge can be customized for the patient and / or teeth. In some embodiments, the radius of curvature of the occlusal edge can be determined based on a 3D model of the patient's teeth. In some embodiments, the radius of curvature and / or placement of the teeth relative to the occlusal edge can be determined by the patient's orthodontic prescription and / or the practitioner's preferences that affect the smile arc. Tubes with curved occlusal edges may be positioned closer to the occlusal edge than stock tubes. In some embodiments, the radius of curvature of the curved gingival edge can be in the range of 0.05-2.0 mm.

[0118] In some embodiments, the orthodontic tube may include a gingival edge that is curved to approximate the gingival margins of the patient's teeth and an occlusal edge that is curved to approximate the occlusal surfaces of the patient's teeth. An example of an orthodontic tube 500 as viewed from the surface of the orthodontic tube 500 is shown in Figure 5. In this example, a middle third 502 defined by the base or overall dimensions and a middle third 504 defined by the dimensions of the area of ​​the tube 500 having a slot are shown. Fracture grooves 508 may be fabricated in the central vertical third (502 or 504) of the ceramic tube 500.

[0119] An example of an orthodontic tube 600 is shown in cross section in FIG. 6. In the example shown in FIG. 6, a fracture groove 602, a horizontal (mesial-distal) slot 604, and an auxiliary slot 606 are shown. The fracture groove 602 may include a weakened area including a curved indentation (groove) of the tooth in the tube base 608 that runs vertically (occlusal-gingival) in the central third of the tube 600. The fracture groove 602 may match the contour of the tooth in the positioning portion of the tube. The fracture groove 602 may be aligned with the vertical midline of the tube or base and / or the deepest part of the auxiliary slot 606. The area of ​​the tube between these features may form the weakened area of ​​the tube 600.

[0120] In some embodiments, the fracturing groove 602 may be a constant depth from the tooth surface, as shown in FIG. 6. In some embodiments, the constant depth fracturing groove 602 may be a nominal or predetermined depth for some or all of the tubes of a patient. For example, groove depths 610, 612, and 614 may all be the same predetermined depth "X". Such a nominal or predetermined depth may range, for example, from 0.10 mm to 1.2 mm. In some embodiments, the constant depth fracturing groove 602 may be a different depth for some or each tube, and may be based on the entry and exit of the tube. For example, the distance from the tooth surface to the deepest point of the fracturing groove 602 may be different for different tubes.

[0121] An example of an orthodontic tube 700 is shown in cross section in FIG. 7. In some embodiments, as shown in FIG. 7, the fracture groove 702 may have a variable depth from the tooth surface. In some embodiments where the fracture groove 702 is variable, the variation may range up to 50% of the distance from the tooth surface to the deepest point of the fracture groove. For example, groove depth 710 may be depth "X", groove depth 712 may be depth "Y", and groove depth 714 may be depth "Z". In some embodiments, the variable depth fracture groove 702 may have a nominal or predetermined maximum depth for some or all tubes of a patient. The nominal or predetermined maximum depth, etc. may be in the range of 0.10 mm to 1.2 mm, for example. In some embodiments, the constant depth fracture groove 702 may have different maximum depths for some or each tube. For example, the distance from the tooth surface to the deepest point of the fracture groove 702 may be different for different tubes.

[0122] Finite element analysis revealed that mesial-distal forces on the sides of the tie wings or edges of the tube would concentrate the forces in the central third of the base of the tube. In some embodiments, the fracture groove 602 may be defined as the area of ​​removed material where such forces would be most concentrated. The addition of the fracture groove 602 reduces the force required to predictably cause tube fracture in the central vertical third of the tube, aiding in the delamination of the ceramic tube from the tooth. The weakened area and fracture force can be optimized by adjusting the dimensions of the groove and / or auxiliary slot.

[0123] The algorithm can be modified to allow different force values ​​based on clinician preference or whether the force values ​​are too high or low for a particular patient population. Adolescents often do not follow best practices in orthodontic treatment, so higher peel force values ​​can be used to ensure that abnormal chewing forces, i.e. biting on a pen, do not cause premature delamination of the tubes. This feature does not need to be adjusted if adults do not have these issues and prefer that the orthodontist not have to use as much force to delaminate the bonds.

[0124] The advantage of the present invention is that it improves consistency of the peel force for customized tubes. By coupling the shape of the stress concentrator to the shape of the tooth and controlling the depth of this stress concentrator with the thickness of the bracket or tube, a more reliable fracture force can be achieved. This improved fracture force consistency allows for a more positive experience, especially when peeling a series of brackets or tubes at once. Additionally, it allows for improved tuning of the exact strength if the currently set strength is found to be too low or too high.

[0125] This auxiliary slot / stress concentrator can be applied to a variety of orthodontic appliances such as brackets, tubes, and attachments. Curved tiewing edges can be applied to improve structural integrity and manufacturability, and the inclination of the auxiliary slot to the fault line can be designed to reduce layer separation and provide high quality manufacturability. The channels in the base 210 can also be curved to match the shape of the tooth, acting as stress concentration points as well as exit channels for excess bonding material.

[0126] By varying the design of the tiewings, slot enclosures, and slots, it may be possible to create the same shape (fracture groove) moving in a mesial / distal direction, or diagonally between the two directions. Changing this direction may reduce the risk of tube delamination when using high-force attachments such as 3M Forsus springs and other orthodontic functional appliances, Class II / III "occlusion correctors."

[0127] Variations of the invention include alternative shapes of the stress concentrators themselves, as well as changes in the orientation of the stress concentrators. The shape of the channel 202 can also be altered while maintaining the custom contour to provide different force profiles, to avoid food entrapment and increase cleanliness, or to enhance the structural integrity of the tube. Another improvement would be to adjust the design to allow the orthodontist to use standard utility pliers (such as Weingart or Howe pliers) or new specialized pliers to debond the tube while the wire is still engaged. This would prevent the patient from accidentally swallowing the tube during peeling, and would greatly increase the efficiency of the peeling process. In this scenario, the algorithm, the channel shape, and the channel location can be adjusted.

[0128] This improved stress concentrator uses a profile with a peak, but a circle, rectangle, or other closed shape can also be used as the stress concentrator profile. Additional shapes may be useful to tailor the exact strength of the tube or provide an easier route to manufacture.

[0129] An example of an orthodontic tube 800 is shown in FIG. 8. In this example, a fracture wall 802 may be fabricated around the base 804 of the tube 800. In some embodiments, the fracture wall 802 may have a constant thickness that may be in the range of 15-140 μm. In some embodiments, the fracture wall 802 may have a variable thickness that may be in the range of 15-140 μm inclusive. In some embodiments, a bonding cement may be inserted into the cavity formed by the fracture wall 1002. In some embodiments, the wall thickness may be constant around all edges of the tube 800, and a normal force 806 (the component of the contact force normal to the surface of the fracture wall 802) may be applied in any direction, such as mesial-distal, occlusal-gingival, or any opposing angle.

[0130] The continuity of the fracture wall 802 around the entire tube provides predictable fracturing of the wall via pliers, allowing peeling of the tube with a combination of pulling and peeling forces that are typically less than the shear bond strength of the bonded tube. For example, pliers may be used that can move around a ligated wire to induce a mesial-distal force 806 on the labial portion of the tube. In some embodiments, such forces may be in the range of 10-180 Newtons. Also shown in this example is a slot 808 (archwire / mesial-distal slot).

[0131] An example of an orthodontic tube 900 is shown in FIG. 9. In this example, multiple retention structures 902 are shown included in the base 904 of the tube 900. An example of a retention structure 1000 is shown in cross section in FIG. 10. In some embodiments, the retention structure 1000 can be any shape that is a three-dimensional figure with a positive draft angle greater than 0°. The draft angle 1002 can be an angle between a normal to a neutral plane 1004, which can be oriented toward the tooth structure or surface, and a side wall 1006 of the retention structure 1000. In some embodiments, in cross section, the retention structure 1000 can be approximately trapezoidal with the neutral plane 1004, which can be a plane oriented toward the tooth structure or surface, being wider than the base plane 1008, which can be the plane of the side of the retention structure 1000 oriented toward the tube body.

[0132] The neutral surfaces 1004 may be flat or may be contoured to the shape of the tooth surface to which they are bonded. In some embodiments where the neutral surface 1004 of each retention structure is flat, the neutral surfaces 1004 of all retention structures may be parallel to the base surface 1008, or the neutral surfaces 1004 of some or all retention structures may be non-parallel to the base surface 1008 such that the overall pattern of retention structures generally contours to the tooth surface. Additionally, the parallel or non-parallel alignment of the neutral surfaces 1004 and the base surface 1008 may affect the draft angle 1002 of each retention structure 1000.

[0133] Adhesive cement can be used to achieve proper retention, but a range of draft angles 1002 designed to compensate for the limitations of a particular three-dimensional printing process are available. For example, to achieve the desired final draft angle, the draft angle in the digital file may need to be designed larger to compensate for overpolymerization, polymerization shrinkage, or other compensation. As long as zero or positive draft angle is obtained from the actual printed part (regardless of the digital file design), proper retention should be achieved.

[0134] 9, the retention structures 902 are shown as half-moon shaped lines or "trenches." However, in some embodiments, the retention structures 902 may be half-moon cones, full cones, squares, rectangles, retention grids or meshes, or any other shape with positive draft at any point intended to enhance bond strength. Such shapes with positive draft may be more efficiently manufactured by three-dimensional printing rather than injection molding or casting.

[0135] An example of a cross-section of an orthodontic tube 1100 on a tooth is shown in FIG. 11. In the example shown in FIG. 11, the retention structures 1102 are shown contoured to the tooth surface (as shown in a three-dimensional vector (e.g., stl or additive manufacturing file format (AMF) representation)). Each structure can be contoured to fit a corresponding area of ​​the tooth surface within a prescribed tube location. In this example, the base cavity 1104 is also shown contoured to ensure that each retention structure maintains its dimensions and all structures have a similar depth. Additionally, a depth 1106 of the contoured cavity 1104 can be defined. An example of this process is described in U.S. Patent Publication No. 20190328493 A1, the contents of which are incorporated herein by reference.

[0136] The advantage of forming the tubes using the AM process is that the tubes are a unibody structure, meaning that the tubes are formed as a unibody structure based on the prescription. There is no need to form the tube face separately from the tube pad and then bond the tube face to the tube pad to achieve customization. Custom unibody tubes allow for more precise application of force, resulting in more predictable treatment outcomes and often fewer visits to the orthodontist for adjustments and wire, bracket and tube adjustments.

[0137] In some embodiments, the orthodontic tube can include a slot with a customized angle of the main portion of the slot. For example, the customized angle can be based on an orthodontic prescription. The system for generating the 3D model of the orthodontic tube structure can be configured to determine the angle of the main portion of the slot based on the orthodontic prescription and generate the 3D model of the orthodontic tube structure with the slot with the determined angle. In some embodiments, the angle of the main portion of the slot can be modified by forming the slot at an angle relative to the longitudinal axis of the tube and / or rotating it relative to the longitudinal axis. The predetermined force can be applied to the tooth through a tube with a slot formed at an angle relative to the longitudinal axis of the tube or rotated relative to the longitudinal axis of the tube. For example, the slot angle or rotation can be used in combination with an archwire to tip, torque, rotate, or move one or more teeth forward or backward.

[0138] 12A (gingival or occlusal view) shows a tube 1210 having a surface including a base 1214 and a tube body 1218. A slot 1222 defined in the tube body 1218 is formed at an upward angle relative to the base 1214 along the mesial-distal longitudinal axis. In some embodiments, the slot 1222 defined in the tube body 1218 is formed at a downward angle relative to the base 1214 along the mesial-distal longitudinal axis. The slot 1222 may cause tooth rotation.

[0139] 12B (buccal view) shows a tube 1210' having a base 1214' and a surface that includes a tube body 1218'. A slot 1222' defined in the tube body 1218' is formed at an oblique angle to the mesial-distal longitudinal axis. In certain embodiments, the angle may be slanted from the gingival edge to the occlusal edge or from the occlusal edge to the gingival edge. The slot 1222' may cause tipping of the tooth.

[0140] FIG. 12C (mesial or distal view) shows a tube 1210'' having a surface including a base 1214'' and a tube body 1218''. A slot 1222'' defined in the tube body 1218'' is rotated along a longitudinal axis. The slot 1222'' can be rotated clockwise or counterclockwise between 0.1 degrees and 45 degrees relative to the longitudinal axis. The slot 1222'' can induce torque in the teeth. In some embodiments, the slot can have a square, substantially square, rectangular, or substantially rectangular cross-section. In some embodiments, the slot can have a cross-section that tapers, for example, from mesial to distal or from distal to mesial.

[0141] The tube body 1218 or 1218' can be a single tube or a split tube body (as described above). The pad of the base 1214 or 1214' can be manufactured to be the negative of the tooth surface. In some embodiments, angled slots allow for a custom base pad design to better conform to the tooth surface and / or allow for a more gingival or more occlusal positioning of the base as described above.

[0142] As described above, alternative design features of the tube may be used by the orthodontist to peel the tube using standard utility pliers. As described herein, in some embodiments, the orthodontic tube may include a peeling structure including a ridge that facilitates peeling of the tube from the tooth. The ridge may be used to apply force to the tube (e.g., with pliers) to remove the tube from the tooth. In some embodiments, the ridge may be positioned for easy access by the clinician. For example, the ridge may be positioned near the interface between the base of the orthodontic tube and the face of the orthodontic tube.

[0143] 13A shows a tube 1300 including a base 1304 and a face 1308 including a slot body that defines a slot 1312. A ridge 1316 is defined around at least a portion of the periphery of the tube base 1304. The ridge 1316 may be disposed at the interface of the tube base 1304 and the tube face 1308.

[0144] 13B shows a tube 1300' including a base 1304' and a face including split slot bodies 1308a, 1308b that define slots 1312a, 1312b, respectively. A ridge 1316' is defined around at least a portion of the periphery of the tube base 1304'. A gap 1320 is defined within the ridge that corresponds to the location of the split in the slot bodies 1308a, 1308b. The gap may represent a stress riser. The ridge 1316' may be located at the interface of the tube base 1304' and the tube face that defines the slot bodies 1308a, 1308b.

[0145] In some embodiments, the ridge is located on the gingival edge surface of the tube, the occlusal edge surface of the tube, or both. The height of the ridge can vary along the mesial / distal axis of the tube structure. The height of the ridge can be from about 0.01 mm to about 1 mm. In some embodiments, the height of the ridge is about 0.04 mm. The height of the gingival ridge can be different from the height of the occlusal ridge.

[0146] FIG. 20 illustrates a gingival ridge 2000, or a portion thereof, according to some embodiments of the techniques described herein. As shown in FIG. 20, the gingival ridge 2000 is proximate the interface between the base of the orthodontic tube and the face of the orthodontic tube. In the example of FIG. 20, the height 2004 of the ridge from the base to the gingival / occlusal side is 0.2 mm. In the example of FIG. 20, the thickness 2002 of the ridge at the edge is 0.2 mm. As shown in the example of FIG. 20, the ridge widens as it approaches the base of the tube. In some embodiments, the height and / or thickness of the ridge may vary along the mesial-distal axis of the orthodontic tube.

[0147] FIG. 14 shows a tube 1400 including a base 1404 and a face 1408 including a slot body that defines a slot 1412. A chamfer 1416 is defined around the periphery of the base 1404. The chamfer can be located at the interface of the tube base 1404 and the tooth. The chamfer can be located at the gingival tube-tooth interface, the occlusal tube-tooth interface, or both. The chamfer can be configured to mate with an orthodontic tool for stripping the tube. For example, the tool can be placed on top of the chamfer or the tool can be placed next to the chamfer. The height of the chamfer can be about 0.01 mm to about 1 mm. In some embodiments, the height of the chamfer is about 0.04 mm. In some embodiments having a split tube body, a gap is formed at the chamfer.

[0148] The dimensional accuracy of an additively manufactured part can be improved by adjusting which pixels are active during polymerization. Typically, the accuracy of DLP printing is limited by the pixel size and the amount of excess polymerization that occurs as a result of light scattering. The dimension of a line in a layer can be expressed as N*S+2P, where N is the number of pixels, S is the pixel size, and P is the amount of excess polymerization. P is typically a factor of various aspects of the printer (light intensity and scattering, material composition, etc.) and the part being printed, and cannot be controlled. Since S is a property of the printer being used and cannot be adjusted, N is the only controllable parameter. As shown in Figure 15A, the white squares represent the pixels that are turned on by the design, and the blue shape P represents the resulting polymerization area.

[0149] For applications that require a high degree of dimensional accuracy, this can be a limiting factor, as designers can only adjust parts in pixel-sized increments. Grayscaling can be used to control the amount of overpolymerization (for example, by adjusting the intensity of certain pixels), but this can be a tedious process that requires specialized software. A unique grayscale pattern must be developed for each part, and depending on the part's geometry, each layer of the print may require a different pattern.

[0150] In some embodiments, the amount of overpolymerization (P) can be controlled by turning off certain pixels along the edges of the part. In some embodiments, a system for generating a 3D model of an orthodontic tube structure can be configured to determine a grayscale pattern of a portion of the orthodontic tube structure (e.g., a slot, a slot edge, and / or other portions). The grayscale pattern can be indicative of a pattern of polymerization applied by the AM device at different locations of the portion of the orthodontic tube structure during manufacturing of the orthodontic tube. The system can be configured to apply the grayscale pattern to the portion of the orthodontic tube structure (e.g., a slot or portions thereof).

[0151] In some embodiments, the grayscale pattern may indicate various levels of polymerization intensity. In one embodiment, the grayscale pattern may indicate locations of polymerization where polymerization should be turned off and locations where polymerization is turned on. For example, the grayscale pattern may indicate that polymerization is turned on at one or more pixels of a portion of the 3D model of the orthodontic tube structure and polymerization is turned off at one or more other pixels. In some embodiments, the grayscale pattern may be determined based on the specifications of the AM device, the dimensions of the orthodontic tube structure, and / or other factors.

[0152] FIG. 15B shows an example of a grayscale pattern of slots in an orthodontic tube structure according to some embodiments of the techniques described herein. In FIG. 15B, the white squares represent pixels that are turned on by design, the black squares represent pixels that are turned off, the blue shape P represents the resulting polymerization area adjacent to a row of active pixels, and the blue shape P' represents the resulting polymerization area adjacent to a row of pixels that contains deactivated pixels. By adjusting which pixels are turned on or off along the edge of the part, P' can be controlled to achieve dimensional accuracy smaller than the printer's pixel size.

[0153] In some embodiments, two or more adjacent pixels may be deactivated. In some embodiments, the deactivated adjacent pixels may be along an edge or stacked. In some embodiments, two or more adjacent pixels may be activated, and a third pixel on either side of the activated adjacent pixels may be deactivated.

[0154] The pixel changes can be incorporated into the original part design and can be edited using modeling software, for example, during step 108 shown in FIG. 1. FIGS. 16A and 16B are examples of how this process can affect the dimensions of the printed slots. FIG. 16A shows slot 1600 defined in slot body 1604. FIG. 16B shows slot 1600' defined in slot body 1604'. Although slot 1600 and slot 1600' have the same design width, due to the alternating pixels along the edges, the actual printed width of slot 166' is increased by about 40 microns, which is the same as the pixel size of the printer on which these parts were printed. Slot wall 1608 has a flatter surface and slot wall 1608' has a wavy surface, with each wave corresponding to a deactivated pixel.

[0155] Currently, patients pay more for ceramic tubes than metal because of the improved aesthetics. For example, many patients want tubes that match the color of the tooth they are attached to. This may make the tube less visible and improve appearance. As another example, embodiments of the present invention may provide the ability to create transparent tubes, which may provide a further improved appearance. Additionally, embodiments of the present invention may provide the ability to create tubes of nearly any color desired or selected, for example, bright colored tubes for use with children and some adults. Similarly, embodiments of the present invention may provide the ability to create tubes with visible shapes that are not dictated by function, such as shapes of animals, vehicles, toys, etc., for use with children and some adults.

[0156] Ceramic slurry-based AM technology allows engineers to rapidly turn their designs into ceramic products, and the manufacturing steps for the tubes are fewer and can be performed on-site, saving time and costs.

[0157] The described technology will be cost-effective to the extent that individual orthodontists can purchase the necessary equipment and software. This will allow for a simplified tube inventory instead of having to stock tubes with different prescriptions. Digital light processing (lithography-based) and laser lithography additive manufacturing of ceramics have many advantages for the production of orthodontic tubes compared to selective laser sintering / melting (SLM), which uses thermal energy, and 3D printing (3DP) systems, which use binders and polymer-derived ceramics (PDC). For example, DLP may offer higher surface quality, better object resolution, and improved mechanical properties. PDC, structured using light in a stereolithography or mask exposure process, can also be used as a ceramic AM method for tube production.

[0158] The described techniques can be used to fabricate tubes from materials such as high strength oxide, nitride, carbide ceramics, metals, including but not limited to aluminum oxide (Al2O3), zirconium oxide (ZrO2), alumina toughened zirconia (ATZ), zirconia toughened alumina (ZTA), lithium disilicate, leucite silicate, and silicon nitride, as well as metals such as stainless steels 17-4PH or 316L, titanium (Ti / Ti-Al6-V4), cobalt chromium (CoCr), tungsten and tungsten carbide / cobalt (W or WC / Co), silicon carbide (SiC), molybdenum (Mo) and precious metals, e.g., gold (Au).

[0159] The technique described can be used to achieve true straight-wire appliances with improved tube placement accuracy, reducing treatment time and errors; or it can be used in conjunction with custom bent archwires to achieve ideal results. Custom lingual tubes can be manufactured in this manner to accept pre-bent customized archwires as described in US 2007 / 0015104. Custom labial tubes can also be fitted with pre-bent wires.

[0160] The procedure of layered additive manufacturing (AM) methodology of labial / lingual orthodontic tubes by lithography-based DLP (e.g., U.S. Patent No. 8,623,264), which is incorporated herein by reference, can be briefly summarized as follows: a photopolymerizable material located in at least one trough having a light-transmitting horizontal bottom is polymerized by illumination on at least one horizontal platform, the platform having a pre-specified geometric shape and protruding into the trough within the illumination field, the platform is moved vertically to form subsequent layers, photopolymerizable material is added to the last formed layer, and repetition of the aforementioned steps results in a layered structure of the orthodontic tube in the desired prescription / mold, resulting from a series of layer shapes determined from a CAD software.

[0161] The troughs can be moved horizontally to a supply position, and the supply device brings the photopolymerizable material into the illumination field at least at the bottom of the trough before at least one trough is moved to an illumination position where the illumination field is located below the platform and above the lighting unit, illumination occurs and a ``green tube'' appears.

[0162] Photopolymerizable materials or photoreactive suspensions (slurries) can be prepared based on commercially available difunctional and monofunctional methacrylates. An exemplary material can be a slurry blend of about 0.01-0.025 wt% highly reactive photoinitiator, about 0.05-6 wt% dispersants, absorbers, and about 2-20 wt% non-reactive diluents. High strength oxide ceramics such as aluminum oxide (Al2O3) and zirconium oxide (ZrO2) powders can be used as solid loadings, but the process may be extended to other ceramic materials and metals.

[0163] In some embodiments, the amount of alumina or zirconia in the slurry can be greater than or equal to about 49%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or about 49%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 95%, or 99% by weight. In some embodiments, the amount of alumina or zirconia in the slurry can be 50-60%, 60-70%, 70-80%, 80-90%, 90-95%, or 95-100% by weight. The purity of the sintered alumina or zirconia may be 95% or greater, or about 95.5%, 96%, 96.5%, 97%, 97.5%, 98%, 98.5%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8% or 99.9% by weight. The reduction in part size from the green body to the sintered tube may be about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%.

[0164] The acrylate moiety can be monomeric, oligomeric, or polymeric. The acrylate moiety can include multiple methacrylate moieties. The weight content of the acrylate moieties can be between 5% and 50% by weight. In some embodiments, the weight content is 5, 10, 15, 20, 25, 30, 35, 40, or 45% by weight or more. The acrylate moieties can be methacrylate moieties or acrylic acid esters.

[0165] 21 shows a flow chart of an example process 2100 for manufacturing an embodiment of an orthodontic tube described herein, according to some embodiments of the techniques described herein. Process 2100 may be performed by any suitable computer system. For example, process 2100 may be performed by computer system 700 described herein with reference to FIG.

[0166] Process 2100 begins at block 2102, where the system acquires a 3D model of one or more teeth of a patient. The 3D model of the patient's teeth may be acquired using a medical imaging device. For example, the 3D model of the patient's teeth may be acquired using a CT scanner, an intraoral scanner, a coordinate measuring machine, a laser scanner, or a structured light digitizer.

[0167] Next, process 2100 proceeds to block 2104, where the system generates a 3D model of the orthodontic tube structure using the 3D model of the patient's one or more dentitions. In some embodiments, the system may be configured to generate the 3D model of the orthodontic tube structure based on an orthodontic prescription. Various embodiments of the orthodontic tube structure are described herein with reference to Figures 2-16B. For example, the system may generate the 3D model of the orthodontic tube structure as a CAD model or other type of 3D model.

[0168] Process 2100 then proceeds to block 2106, where the system uses an AM device to create a customized orthodontic tube based on the 3D model of the orthodontic tube structure. In some embodiments, the system may be configured to send the 3D model of the orthodontic tube structure to the AM device for creation. In some embodiments, the system may be configured to use the AM device to send the 3D model of the orthodontic tube structure to another party (e.g., a manufacturer) for creation. In some embodiments, the system may be a component of an AM device that may be used to create the customized orthodontic tube. In some embodiments, the system may be configured to trigger the generation by the AM device (e.g., by sending a command to the AM device).

[0169] In some embodiments, the AM device may be any suitable AM ​​device, for example, the AM device may be a photopolymerization device, a material jetting device, a binder jetting device, a power bed fusion device (e.g., a selective post-sintering device, a selective laser melting device, an electron beam melting device, or a direct metal laser sintering device), a sheet lamination device, or a direct energy deposition device.

[0170] An exemplary block diagram of a computer system 700 on which the above-described processes may be implemented is shown in FIG. 17. The computer system 700 is typically a programmed general-purpose computer system, such as a personal computer, a workstation, a server system, and a minicomputer or mainframe computer. The computer system 700 includes one or more processors (CPUs) 702A-702N, input / output circuitry 704, a network adapter 706, and a memory 708. The CPUs 702A-702N execute program instructions to perform the functions of an embodiment of the present invention. Typically, the CPUs 702A-702N are one or more microprocessors, such as an INTEL PENTIUM processor.

[0171] 17 illustrates an embodiment in which computer system 700 is implemented as a single multi-processor computer system, with multiple processors 702A-702N sharing system resources, such as memory 708, input / output circuitry 704, and network adapter 706. However, the present invention also contemplates embodiments in which computer system 700 is implemented as multiple networked computer systems, which may be single-processor computer systems, multi-processor computer systems, or a combination thereof.

[0172] The input / output circuitry 704 provides the ability to input data to or output data from the computer system 700. For example, the input / output circuitry may include input devices such as a keyboard, mouse, touchpad, trackball, scanner, etc., output devices such as a video adapter, monitor, printer, modem, etc. The network adapter 706 connects the device 700 to a network 710. The network 710 may be any public or private LAN or WAN, including but not limited to the Internet.

[0173] The memory 708 stores program instructions that are executed by the CPU 702 to perform functions of the computer system 700, and data that is used and processed by the CPU 702. The memory 708 may be, for example, random access memory (RAM), read only memory (ROM), programmable read only memory (PROM), electrically erasable programmable read only memory (EEPROM), flash memory, etc., as well as electromechanical memory such as magnetic disk drives, tape drives, optical disk drives, etc., that may use an integrated drive electronics (IDE) interface, or enhanced IDE (EIDE) or ultra direct memory access (UDMA), or small computer system interface (SCSI) based interfaces, such as SCSI fast, wide SCSI, SCSI fast and wide, Serial Advanced Technology Attachment (SATA), or variations or extensions thereof, or Fibre Channel Arbitrated Loop (FC-AL) interface, or variations or extensions thereof, or variations or extensions thereof.

[0174] The contents of memory 708 vary depending on the functions that computer system 700 is programmed to perform. In the example shown in FIG. 17, memory contents are shown included in a system in which a content analysis platform is implemented. However, one skilled in the art will recognize that these functions, along with the memory contents associated with those functions, may be included on one system or distributed across multiple systems based on well-known engineering considerations. Embodiments of the present invention contemplate all such configurations.

[0175] In the example shown in Fig. 17, the memory 708 can include a dentition data measurement routine 712, a 3D CAD tooth model construction routine 714, a 3D CAD tooth model editing routine 716, a tube design routine 718, a manufacturing control data generation routine 720, and an operating system 722. The dentition data measurement routine 712 can acquire and process dentition data, such as may be generated by a CT layer scan or a non-contact 3D scanner directly on the patient's teeth, or can use 3D readings on a previously cast tooth model. The 3D CAD tooth model construction routine 714 can build a 3D CAD model of the measured teeth based on the dentition data.

[0176] The 3D CAD tooth model editing routine 716 may be used to reposition the teeth in the model to the desired treatment outcome and may be used to accept further additional information such as desired torque, offset, selected tube angle, occlusal / incisal coverage of the placement guide, etc. The tube design routine 718 may be used to design and generate a 3D CAD model based on the input 3D CAD model of the measured teeth, the model of the desired treatment outcome, and the additional information entered. The manufacturing control data generation routine 720 may be used to generate manufacturing control data used by the production facility. The operating system 722 provides the overall system functionality.

[0177] It should be noted that additional functionality may be implemented in an end user device, such as the end user device 104 shown in FIG. 1. An end user system may be a computer system having a structure similar to that shown in FIG. 17. Such an end user system may include a geometric analysis routine that performs a geometric analysis of the location of an advertisement or content. Similarly, such an end user system may include a resource-based analysis routine to determine whether the computer is optimizing the advertisement or content it displays on the screen.

[0178] As shown in FIG. 17, embodiments of the present invention contemplate implementation on one or more systems that provide multi-processor, multi-tasking, multi-processing, and / or multi-threaded computing, as well as systems that provide only single-processor, single-threaded computing. Multi-processor computing uses multiple processors to perform computing. Multi-tasking computing involves using multiple operating system tasks to perform computing. A task is an operating system concept that refers to the combination of an executing program and bookkeeping information used by the operating system. Each time a program is executed, the operating system creates a new task for that program. A task is like an envelope for a program, in that it identifies the program with a task number and attaches other bookkeeping information to it.

[0179] Many operating systems, such as Linux, UNIX, OS / 2, and Windows, can perform many tasks simultaneously and are called multitasking operating systems. Multitasking is the ability of an operating system to run multiple executables at the same time. Each executable runs in its own address space. This means that there is no way for executables to share memory. This has an advantage because it is not possible for any program to damage the execution of other programs running on the system. However, programs have no way to exchange information other than through the operating system (or by reading files stored in the file system). Multiprocess computing is similar to multitasking computing, as the terms task and process are often used interchangeably, although some operating systems make a distinction between the two.

[0180] The various methods or processes outlined herein may be coded as software executable on one or more processors employing any of a variety of operating systems or platforms. Further, such software may be written using any of a number of suitable programming languages ​​and / or programming or scripting tools, and may be compiled as executable machine code or intermediate code that runs on a virtual machine or suitable framework.

[0181] In this regard, the various inventive concepts may be embodied as at least one non-transitory computer-readable storage medium (e.g., a computer memory, one or more floppy disks, compact disks, optical disks, magnetic tapes, flash memories, circuitry in field programmable gate arrays or other semiconductor devices, etc.) encoded with one or more programs that, when executed on one or more computers or other processors, implement various embodiments of the invention. The non-transitory computer-readable medium may be portable such that the programs stored thereon may be loaded into any computer resource to implement the various aspects of the invention described above.

[0182] The terms "program," "software," and / or "application" are used herein in a general sense to refer to any type of computer code or set of computer-executable instructions that can be used to program a computer or other processor to implement various aspects of the embodiments discussed above. It should be further understood that, according to one aspect, one or more computer programs that, when executed, perform the methods of the present invention need not reside on a single computer or processor, but may be distributed in a modular manner among different computers or processors to implement various aspects of the present invention.

[0183] Computer-executable instructions may take many forms, such as program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Typically the functionality of the program modules may be combined or distributed as desired in various embodiments.

[0184] Also, the data structure may be stored in a non-transitory computer-readable storage medium in any suitable format. The data structure may include fields that are related by location within the data structure. Such relationships may similarly be achieved by assigning to the fields storage locations within the non-transitory computer-readable medium that convey the relationship between the fields. However, any suitable mechanism may be used to establish relationships between information within fields of the data structure, including the use of pointers, tags, or other mechanisms that establish relationships between data elements.

[0185] Various inventive concepts may be embodied as one or more methods, examples of which are provided. The acts performed as part of a method may be ordered in any suitable manner. Thus, while shown as sequential acts in the exemplary embodiments, embodiments may be constructed in which acts are performed in an order different from that shown, which may include performing some acts simultaneously.

[0186] The indefinite articles "a" and "an" as used herein and in the claims should be understood to mean "at least one" unless expressly indicated to the contrary. As used herein, the phrase "at least one" refers to a list of one or more elements and should be understood to mean at least one element selected from any one or more elements in the list of elements, but not necessarily including at least one of each element specifically listed in the list of elements, and not necessarily excluding combinations of elements in the list of elements. This definition also allows for the optional presence of elements other than those specifically identified in the list of elements to which the phrase "at least one" refers, whether related or unrelated to the elements specifically identified.

[0187] The term "and / or" as used herein and in the claims should be understood to mean "either or both" of the elements so conjoined, i.e., elements, sometimes conjunctively and other times disjunctively. Multiple elements listed with "and / or" should be interpreted in the same way, i.e., "one or more" of the elements so conjoined. Other elements, whether related or unrelated to the elements specifically identified, may optionally be present other than the elements specifically identified by the "and / or" clause. Thus, as a non-limiting example, a reference to "A and / or B", when used in conjunction with open-ended language such as "comprising", refers in one embodiment to A only (optionally including elements other than B); in another embodiment to B only (optionally including elements other than A); and in yet another embodiment to both A and B (optionally including other elements).

[0188] "Or" as used herein and in the claims should be understood to have the same meaning as "and / or" defined above. For example, when separating items in a list, "or" or "and / or" should be construed as inclusive, i.e., including not only at least one of a number or list of elements, but also a plurality, and optionally including additional unlisted items. Only terms clearly indicated to the contrary, such as "only one of" or "exactly one of," or, when used in the claims, "consisting of," shall refer to the inclusion of exactly one element of a number or list of elements. In general, the term "or" as used herein shall only be construed as indicating exclusive alternatives (i.e., "either / but not both"), such as "either," "one of," "only one of," or "only one of," when preceded by a term of exclusivity. When used in the claims, "consisting essentially of" shall have its ordinary meaning as used in the field of patent law.

[0189] The use of ordinal terms such as "first," "second," "third," etc. to modify a claim element in a claim does not, in itself, imply a priority, precedence, or ordering of a claim element relative to other claims, or the chronological order in which the actions of a method are performed. Such terms are used solely as labels to distinguish one claim element with a particular name from another element with the same name (but for purposes of the use of ordinal terms).

[0190] The phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of "including," "including," "having," "containing," "involving," and variations thereof are meant to encompass the items listed thereafter as well as additional items.

[0191] Although several embodiments of the present invention have been described in detail, various modifications and improvements will be readily apparent to those skilled in the art. Such modifications and improvements are intended to be within the spirit and scope of the present invention. Accordingly, the foregoing description is by way of example only and is not intended to be limiting. The present invention is limited only as defined by the appended claims and equivalents thereof.

Claims

**Claim 1** A method of manufacturing a customized orthodontic tube for a patient, the method comprising: obtaining a three-dimensional (3D) model of one or more dental arches of the patient; using the 3D model of one or more dental arches of the patient to generate a 3D model of an orthodontic tube structure, the orthodontic tube structure including a slot surrounded by a plurality of walls for receiving a wire, wherein one or more ends of the plurality of walls are angled with respect to the proximal surface of the orthodontic tube structure; and using a stereolithography device to create a customized orthodontic tube based on the 3D model of the orthodontic tube structure The method as described above. **Claim 2** further comprising determining an angle of a major portion of the slot based on an orthodontic prescription; generating a 3D model of the orthodontic tube structure includes generating a slot having the determined angle of the major portion of the slot, The method according to claim 1. **Claim 3** The method according to claim 2, wherein the orthodontic prescription includes an indication of a desired torque, tip, rotation, or combination thereof for the patient's teeth relative to associated teeth. **Claim 4** the slot includes four walls and four corners; and the slot includes a dovetail hole at each corner of the slot to prevent material from polymerizing at the corners of the slot during stereolithography of the customized orthodontic tube, The method according to claim 1. **Claim 5** further comprising determining the size and shape of the slot based on the size and shape of the wire received in the slot; generating a 3D model of the orthodontic tube structure includes generating a slot having the determined size and shape, The method according to claim 1. **Claim 6** generating a 3D model of the orthodontic tube structure includes: determining a grayscale pattern for at least a portion of the slot, the grayscale pattern indicating a polymerization pattern applied by the stereolithography device; and applying the grayscale pattern to at least a portion of the slot The method according to claim 1. **Claim 7** The method according to claim 6, wherein the grayscale pattern includes a plurality of pixels, each pixel indicating an amount of material to be polymerized at a respective position within the 3D model of the orthodontic tube structure. **Claim 8** The method of claim 6, wherein the grayscale pattern includes a plurality of pixels indicating whether polymerization is on or off at each position within the 3D model of the orthodontic tube structure.

9. The method of claim 1, wherein the orthodontic tube structure includes a notch through which material flowing through the slot can exit the orthodontic tube structure.

10. The orthodontic tube structure includes an interface adjacent to a build plate on which a customized orthodontic tube is created; and The notch is at least partially located at an interface adjacent to the build plate, according to the method of claim 9.

11. A customized orthodontic tube created by a stereolithography device using a 3D model of an orthodontic tube structure generated using a 3D model of one or more dental arches of a patient, the following: A slot surrounded by a plurality of walls for receiving a wire, wherein one or more ends of the plurality of walls are angled with respect to the proximal surface of the customized orthodontic tube, said slot Including, said customized orthodontic tube.

12. The customized orthodontic tube of claim 11, wherein the angle of the main portion of the slot is based on an orthodontic prescription.

13. The customized orthodontic tube of claim 11, wherein the slot is shaped based on the shape of the wire received by the slot.

14. The customized orthodontic tube of claim 11, further including a notch that allows material to flow out of the slot through the notch when the customized orthodontic tube is connected to a base plate.

15. The customized orthodontic tube of claim 11, further including two parts, each having a respective slot extending through that part.

16. The respective slots of the two parts are as follows: A first side surface with angled ends of one or more slot walls; and A second side surface with non-angled ends of one or more slot walls Including, the customized orthodontic tube of claim 15.

17. The customized orthodontic tube of claim 15, wherein the slots of the two parts are aligned such that the angle of the main portion of the first slot is the same as the angle of the main portion of the second slot.

18. The customized orthodontic tube according to claim 11, wherein the slot is shaped to receive a generally rectangular wire.

19. The customized orthodontic tube according to claim 11, wherein at least some of the plurality of walls are substantially parallel to each other.

20. The customized orthodontic tube according to claim 11, wherein the ends of one or more walls are each angled between about 20 degrees and 80 degrees from the proximal face of the customized orthodontic tube.

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