Fabrication of accessory templates and multi-material calibrators

Abstract

Systems, methods, and apparatus for producing an orthodontic appliance are provided. The orthodontic appliance includes an outer shell including a plurality of cavities shaped to accommodate a patient's teeth and to generate one or more of a force or a torque in response to the appliance being worn on the patient's teeth. The orthodontic appliance may include an internal structure having a stiffness different from that of the outer shell. The internal structure may be positioned on an inner surface of the outer shell to distribute one or more of a force or a torque to at least one tooth accommodated within the plurality of cavities.

Description

[0001] This application is a divisional application of the invention patent application of Alleyne Technologies Co., Ltd. (filing date is July 7, 2016, application number is 201680040285.9, invention name is "Manufacturing of accessory templates and multi-material calibrators").

[0002] Cross-references

[0003] This application claims the benefit of U.S. Application Serial No. 15 / 202,342, filed on July 5, 2016, U.S. Application Serial No. 15 / 202,348, filed on July 5, 2016, U.S. Provisional Application No. 62 / 189,282, filed on July 7, 2015, and U.S. Provisional Application No. 62 / 189,259, filed on July 7, 2015, the disclosures of each of which are incorporated herein by reference in their entirety.

[0004] The subject matter of the following co-pending patent applications is related to the present application: U.S. Application Serial No. 15 / 202,472, filed on July 5, 2016, entitled “DIRECT FABRICATION OF ALIGNERS WITH INTERPROXIMAL FORCE COUPLING” (Attorney Docket No. 22773-855.201), which claims the benefit of U.S. Provisional Application No. 62 / 189,263, filed on July 7, 2015; U.S. Application Serial No. 15 / 202,472, filed on July 5, 2016, entitled “DIRECT FABRICATION OF ALIGNERS FOR ARCH No. 15 / 202,452, filed on July 7, 2015, entitled “DIRECT FABRICATION OF ALIGNERS FOR PALATE EXPANSION AND OTHER PRODUCTS” (Attorney Docket No. 22773-857.201), claiming the benefit of U.S. Provisional Application No. 62 / 189,271, filed on July 7, 2015, and U.S. Provisional Application No. 62 / 189,301, filed on July 7, 2015; U.S. Provisional Application No. 15 / 202,452, filed on July 5, 2016 ... APPLICATIONS (DIRECT FABRICATION OF CALIBRATIONS FOR ORAL DELAY AND OTHER APPLICATIONS)” (Attorney Docket No. 22773-859.201), claiming the benefit of U.S. Provisional Application No. 62 / 189,301, filed on July 7, 2015; U.S. Provisional Application No. 62 / 189,271, filed on July 7, 2015; U.S. Provisional Application No. 62 / 189,271, filed on July 7, 2015; U.S. Provisional Application No. 62 / 189,271, filed on July 7, 2015; U.S. Provisional Application No. 62 / 189,271, filed on July 5, 2016, entitled “SYSTEMS, APPARATUSES AND METHODS FOR DENTAL APPLIANCES WITH INTEGRALLY No. 15 / 202,254, filed on July 7, 2015, entitled “SYSTEMS, APPARATUS AND METHODS FOR DENTAL BRACELETS WITH INTEGRALLY FORMED FEATURES” (Attorney Docket No. 22773-860.201), claiming the benefit of U.S. Provisional Application No. 62 / 189,291, filed on July 7, 2015, U.S. Provisional Application No. 62 / 189,312, filed on July 7, 2015, and U.S. Provisional Application No. 62 / 189,317, filed on July 7, 2015; and U.S. Application Serial No. 15 / 202,299, filed on July 5, 2016, entitled “DIRECT FABRICATION OF POWER ARMS” (Attorney Docket No. 22773-861.201).201), which claims the benefit of U.S. Provisional Application No. 62 / 189,291, filed on July 7, 2015, U.S. Provisional Application No. 62 / 189,312, filed on July 7, 2015, and U.S. Provisional Application No. 62 / 189,317, filed on July 7, 2015; and U.S. Provisional Application No. 62 / 189,319, filed on July 7, 2016; and U.S. Provisional Application No. 62 / 189,310, filed on July 7, 2016; and U.S. Provisional Application No. 62 / 189,311, filed on July 7, 2016; and U.S. Provisional Application No. 62 / 189,313, filed on July 7, 2016; and U.S. Provisional Application No. 62 / 189,314, filed on July 7, 2016; and U.S. Provisional Application No. 62 / 189,315, filed on July 7, 2016; and U.S. Provisional Application No. 62 / 189,316, filed on July 5, 2016; and U.S. Provisional Application No. 62 / 189,317, filed on July 7, 2016; and U.S. Provisional Application No. 62 / 189,318, filed on July 7, 2016; and U.S. Provisional Application No. 62 / 189,319, filed on July 7, 2016; and U.S. Provisional Application No. 62 / 189,31 PROPERTIES (Direct Manufacturing of Orthodontic Appliances with Variable Properties)" (Attorney Docket No. 22773-856.201), claiming the benefit of U.S. Provisional Application No. 62 / 189,291, filed on July 7, 2015, U.S. Provisional Application No. 62 / 189,312, filed on July 7, 2015, and U.S. Provisional Application No. 62 / 189,317, filed on July 7, 2015; U.S. Application No. 15 / 202,187, filed on July 5, 2016, entitled "SYSTEMS, APPARATUSES AND METHODS FOR SUBSTANCE DELIVERY FROM DENTAL APPLIANCE (SYSTEM, DEVICE AND METHOD FOR DELIVERY OF SUBSTANCES FROM DENTAL BRACELETS)” (ATTORNEY DOCKET NO. ALGNP006B), which claims the benefit of U.S. Provisional Application No. 62 / 189,303, filed on July 7, 2015, and U.S. Provisional Application No. 62 / 189,318, filed on July 7, 2015; U.S. Application Serial No. 15 / 201,958, filed on July 5, 2016 (ATTORNEY DOCKET NO. 582758:62-15US), entitled “DENTAL MATERIALS USING THERMOSET POLYMERS”, which claims the benefit of U.S. Provisional Application No. 62 / 189,380, filed on July 7, 2015; and U.S. Provisional Application No. 62 / 189,380, filed on July 5, 2016, entitled “DENTAL APPLIANCE HAVING U.S. Application Serial No. 15 / 202,083 (Attorney Docket No. ALGNP006A) for "Ornamental Braces with Decorative Design," which claims the benefit of U.S. Provisional Application No. 62 / 189,303, filed on July 7, 2015, and U.S. Provisional Application No. 62 / 189,318, filed on July 7, 2015, the entire disclosures of which are incorporated herein by reference. Background Art

[0005] Existing orthodontic procedures generally involve repositioning a patient's teeth to a desired arrangement to correct malocclusion and / or improve aesthetics. To achieve these goals, orthodontic appliances such as braces, retainers, shell aligners, etc. may be applied to the patient's teeth by an orthodontist. The appliance may be configured to apply force to one or more teeth to achieve the desired tooth movement. The application of force may be periodically adjusted by the doctor (e.g., by changing the appliance or using a different type of appliance) to incrementally reposition the teeth to the desired arrangement.

[0006] Attachments can also be placed on teeth for dental and orthodontic treatment to help reposition a patient's teeth.

[0007] Existing orthodontic methods and devices for moving teeth are not ideal in at least some respects. In some cases, existing orthodontic methods that employ braces having homogeneous and / or continuous material properties may not provide adequate control over the forces applied to the teeth. For example, existing braces made of a single material may exhibit less than ideal control over the forces applied to a subset of teeth. In some cases, relatively rigid orthodontic braces may require tighter manufacturing tolerances than are ideal, and such manufacturing tolerances may, at least in some cases, adversely affect the accuracy of the forces applied. Also, in at least some cases, the braces may deform at a location away from the teeth to be moved, which may make the accuracy of tooth movement less than ideal.

[0008] Although attachment templates for placing attachments on teeth have been proposed, existing methods and devices may be more difficult to use than is ideal. Also, the accuracy of existing attachment templates may be less than ideal. Existing methods of manufacturing calibration templates may be more time consuming and expensive than is ideal.

[0009] In view of the above, there is a need for improved orthodontic appliances. Ideally, these appliances will produce more precise tooth movement with improved control of the forces applied to the teeth, a more constant amount of force applied to the teeth during treatment, and reduced sensitivity to manufacturing tolerances. Summary of the invention

[0010] Improved systems, methods and devices for repositioning patient teeth are provided herein. An orthodontic appliance for repositioning teeth includes a non-homogeneous property to improve the control of forces and / or torques applied to different subsets of teeth. For example, different parts of the appliance may include different material compositions to produce different local stiffnesses, and different local stiffnesses may be used to produce local forces and / or torques customized for teeth under a specific surface. In some embodiments, the appliance includes a rigid outer shell that generates forces and / or torques and a compliant internal structure that engages with the tooth surface to improve the distribution of forces and / or torques to the teeth. Advantageously, the use of a compliant internal structure connected to the rigid outer shell can reduce fluctuations in the amount of force or torque applied, which can improve the accuracy and reliability of the appliance. Alternatively or in combination, the method for appliance design and manufacture described herein allows identification of spatial correspondences between portions of the outer shell of the appliance and portions of the sheet of material used to form the shell, which can improve the accuracy of manufacturing appliances with different local properties for improving the control of forces and / or torques applied to the teeth.

[0011] In a first approach, an orthodontic appliance for repositioning a patient's teeth according to a treatment plan includes an outer shell including a plurality of cavities shaped to receive the patient's teeth and to generate one or more of a force or a torque in response to the appliance being worn on the patient's teeth. The orthodontic appliance may include an internal structure having a stiffness different from the stiffness of the outer shell. The internal structure may be positioned on an inner surface of the outer shell to distribute one or more of a force or a torque to at least one received tooth.

[0012] In another aspect, a method for designing an orthodontic appliance for repositioning a patient's teeth according to a treatment plan includes receiving a 3D representation of a shell, the 3D representation of the shell including a plurality of cavities shaped to accommodate the patient's teeth. The shell may include a plurality of shell portions, each shell portion being positioned to engage a different subset of the patient's teeth. The method may further include generating a 2D representation corresponding to the 3D representation of the shell. The 2D representation may represent a sheet of material for forming the shell. The sheet of material may include a plurality of sheet portions corresponding to the plurality of shell portions.

[0013] The methods and appliances disclosed herein also improve the placement of accessories on teeth. The appliance can be directly manufactured, allowing the appliance to be manufactured in a cost-effective manner. In many embodiments, the appliance includes a support member that includes one or more attachment structures for holding one or more accessories. A calibration structure is attached to the support member to accommodate at least a portion of the teeth and to place the one or more accessories at one or more predetermined locations on one or more teeth. The one or more attachment structures are configured to release the accessory when the calibration structure is removed from the one or more teeth. In some embodiments, the accessory can be directly manufactured with an adhesive, and a removable cover can be directly manufactured on the adhesive.

[0014] One or more attachment structures may be directly manufactured and constructed to release from the tooth in a variety of ways. One or more attachment structures may be sized and shaped to retain an accessory. One or more attachment structures may be sized and shaped to retain an accessory by means of a gap extending between a support and the accessory. One or more attachment structures may include one or more extensions extending between the support and the accessory. One or more attachment structures may include multiple extensions extending between the support and the accessory. One or more attachment structures may include a separator sized and shaped to separate the accessory from the support. One or more attachment structures may include a recess formed in the support sized and shaped to separate the accessory from the support.

[0015] While the appliance can be manufactured in a variety of ways, in many embodiments, the appliance is manufactured in response to a three-dimensional scan of the patient's mouth. The three-dimensional scan of the patient's mouth can be received. A three-dimensional shape profile of the support member is determined in response to the three-dimensional scan data, and a three-dimensional shape profile of the alignment structure is determined in response to the scan data. A three-dimensional shape profile of one or more attachment structures can be determined in response to the three-dimensional scan data to release the attachment when the alignment structure is removed from one or more teeth.

[0016] References

[0017] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The novel features of the present invention are particularly set forth in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description which sets forth illustrative embodiments in which the principles of the present invention are utilized, wherein:

[0019] Figure 1Aillustrates a tooth repositioning appliance according to various embodiments;

[0020] Figure 1B illustrates a tooth repositioning system according to various embodiments;

[0021] Figure 2 A method of orthodontic treatment using multiple appliances is shown according to various embodiments;

[0022] Figure 3A and Figure 3B A portion of an orthodontic appliance including a rigid outer shell and a compliant inner structure is shown according to various embodiments;

[0023] Figure 3C illustrates a portion of a three-layer orthodontic appliance according to various embodiments;

[0024] Figure 4A shows a cross-section of a three-layer orthodontic appliance having a rigid outer layer and a compliant inner layer according to various embodiments;

[0025] Figure 4B illustrates a cross-section of an orthodontic appliance having a compliant inner layer with a thickened portion according to various embodiments;

[0026] Figure 4C illustrates a cross-section of an orthodontic appliance including a protrusion formed in a rigid outer layer according to various embodiments;

[0027] Figure 4D A therapeutic system including multiple rigid outer shells and a single compliant inner shell is shown according to various embodiments;

[0028] Figure 5A An orthosis having a plurality of discrete spacer structures is shown according to various embodiments;

[0029] Figure 5B An orthotic device having a plurality of discrete plug structures is shown according to various embodiments;

[0030] Figure 5C An orthosis having a plurality of discrete expansion structures is shown according to various embodiments;

[0031] Figure 5D shows exemplary load-displacement curves for an orthosis according to various embodiments;

[0032] Figure 5E An orthosis having a plurality of discrete spacer structures is shown according to various embodiments;

[0033] Fig. 5F An orthosis having a plurality of connected spacer structures is shown according to various embodiments;

[0034] Figure 5G An orthosis having a plurality of discrete spacer structures is shown according to various embodiments;

[0035] Figure 5H An orthosis having a plurality of discrete spacer structures is shown according to various embodiments;

[0036] Fig. 6A An aligner including an internal structure for engaging tooth-mounted attachments is shown according to various embodiments;

[0037] Figure 6B An orthodontic appliance including compliant tooth-mounted attachments is shown according to various embodiments;

[0038] Figure 6C A compliant accessory mounting structure with a protective layer is shown according to various embodiments;

[0039] Fig. 7A , Figure 7B and Figure 7C schematically illustrates independent force application on teeth according to various embodiments;

[0040] Fig. 8A shows the spatial correspondence between the patient's teeth, orthodontic appliances, and material sheets according to various embodiments;

[0041] Figure 8B A sheet of material for forming an orthotic device is shown according to various embodiments;

[0042] Figure 8C According to multiple embodiments Figure 8B A cross section of a sheet of material;

[0043] Fig.8D According to multiple embodiments Figure 8B A cross section of a sheet of material;

[0044] Fig. 9 Methods for designing and manufacturing orthodontic appliances according to various embodiments are shown;

[0045] Fig. 10A An additive manufacturing process for manufacturing an orthotic device according to various embodiments is shown;

[0046] Fig. 10B illustrates a subtractive manufacturing process for manufacturing an orthotic device according to various embodiments;

[0047] Fig.11A and Fig. 11B Schematic diagram illustrating manufacturing a material sheet from multiple overlapping material layers according to various embodiments.

[0048] FIG. 12A to FIG. 12Cillustrates manufacturing a sheet of material from a plurality of non-overlapping material portions according to various embodiments;

[0049] Fig.13 A method for digitally planning orthodontic treatment according to various embodiments is shown;

[0050] Fig.14 is a simplified block diagram of a data processing system according to various embodiments;

[0051] Fig.15 A method for designing an orthodontic appliance according to various embodiments is shown;

[0052] Fig.16 A method for designing an orthodontic appliance according to various embodiments is shown;

[0053] Fig.17A illustrates a directly manufactured accessory template according to various embodiments; and

[0054] Fig. 17B Shows such as Fig.17A Detailed view of the receptacle of the accessory template shown. DETAILED DESCRIPTION

[0055] The present disclosure provides systems, methods, and apparatus for improved orthodontic treatment of a patient's teeth. In some embodiments, the present disclosure provides an improved orthodontic brace having different portions with different properties. Utilizing braces having different local properties as described herein, control over the application of force and / or torque to subsets of different teeth can be improved, thereby enhancing the predictability and effectiveness of orthodontic treatment. For example, an orthodontic brace may include multiple portions with different stiffnesses (e.g., relatively rigid portions and relatively compliant portions) so as to provide more consistent application of force and / or torque even when the manufacturing tolerances of the brace are relatively poor. In addition, the brace design and manufacturing methods described in the present disclosure can enhance the accuracy and flexibility of producing braces having different local properties, thereby allowing the production of more complex and customized braces.

[0056] In one embodiment, an orthodontic appliance for repositioning a patient's teeth according to a treatment plan is provided. The appliance may include an outer shell including a plurality of cavities shaped to receive the patient's teeth and to generate one or more of a force or a torque in response to the appliance being worn on the patient's teeth; and an internal structure having a stiffness different from the stiffness of the outer shell. The internal structure may be positioned on an inner surface of the outer shell to distribute one or more of the force or torque to at least one tooth received in the plurality of cavities.

[0057] In another aspect, an orthodontic appliance for repositioning a patient's teeth according to a treatment plan is provided. The appliance may include an outer shell including a plurality of tooth-receiving cavities shaped to exert one or more forces or torques on the patient's teeth; and an internal structure positioned on an inner surface of the outer shell. The internal structure may have a stiffness different from a stiffness of the outer shell, such that the internal structure is configured to exhibit a greater amount of deformation than that exhibited by the outer shell.

[0058] In some embodiments, the stiffness of the internal structure is less than the stiffness of the outer shell. The internal structure can be configured to present a first configuration before the brace is placed on the patient's teeth, and to present a second configuration after the brace is placed on the patient's teeth. The first configuration can be different from the second configuration with respect to one or more of the following: a thickness profile of the internal structure, a cross-sectional shape of the internal structure, or an inner surface profile of the internal structure. The internal structure can be configured to present an amount of deformation that is greater than the amount of deformation presented by the outer shell when the brace is worn on the patient's teeth. The deformation of the internal structure can include one or more of the following: a change in the thickness profile of the internal structure, a change in the cross-sectional shape of the internal structure, or a change in the inner surface profile of the internal structure. The outer shell can be substantially non-deformed when the brace is worn on the patient's teeth.

[0059] In some embodiments, the inner structure comprises a compressible material.The inner structure may have an elastic modulus in a range from about 0.2 MPa to about 20 MPa.

[0060] In some embodiments, the inner surface contour of the outer shell is different from the surface contour of at least one tooth, thereby generating one or more forces or torques when the aligner is worn on the patient's teeth. For example, the inner surface contour of the outer shell may include a position or orientation of a tooth receiving cavity that is different from the position or orientation of the surface contour of at least one tooth received in the tooth receiving cavity. The inner surface contour of the outer shell may include a protrusion extending inwardly toward the at least one tooth, and wherein the internal structure is positioned between the protrusion and the at least one tooth.

[0061] In some embodiments, the inner structure includes a continuous inner layer positioned between the outer shell and the patient's teeth. The continuous inner layer can be removably coupled to the outer shell or permanently affixed to the outer shell. The continuous inner layer can include a first layer portion having an increased thickness relative to a second layer portion, and the first layer portion can be positioned to engage at least one tooth to distribute one or more of a force or a torque.

[0062] In some embodiments, the internal structure includes one or more discrete spacer structures positioned to engage at least one tooth. The one or more discrete spacer structures can engage at least one accommodated tooth via one or more attachments mounted on the at least one tooth. Optionally, the internal structure can include a plurality of discrete spacer structures, each spacer structure positioned to engage a different portion of at least one tooth. The one or more discrete spacer structures can be solid. Alternatively, the one or more discrete spacer structures can be hollow. In some embodiments, the one or more discrete spacer structures are filled with a fluid, which is optionally maintained at a substantially constant pressure.

[0063] In some embodiments, the internal structure is attached to the inner surface of the outer shell.Alternatively or in combination, the internal structure may be attached to a tooth surface or an attachment mounted on a tooth surface.

[0064] In some embodiments, the orthosis further comprises an outermost layer attached to the outer surface of the outer shell. The stiffness of the outermost layer may be less than or greater than the stiffness of the outer shell. The outermost layer may be configured to resist scratching, abrasion, staining, or biological interaction. The outermost layer may have a hardness greater than or equal to about 70 Shore D.

[0065] In some embodiments, the orthosis further comprises an innermost layer coupled to the inner surface of the internal structure. The innermost layer may have a stiffness less than or greater than the stiffness of the internal structure. The innermost layer may be configured to resist scratching, abrasion, staining, or biological interaction. The innermost layer may have a hardness greater than or equal to about 70 Shore D.

[0066] In some embodiments, the internal structure includes a textured surface configured to direct saliva away from or toward a surface of the at least one tooth.

[0067] In some embodiments, the internal structure is formed by one or more of milling, etching, coating, spraying, stereolithography or printing. Optionally, the internal structure is formed as a single piece with the outer shell by direct manufacturing techniques. Direct manufacturing techniques can include one or more of vat photopolymerization, material jetting, adhesive jetting, material extrusion, powder bed fusion, sheet lamination or directed energy deposition. Direct manufacturing techniques can include multi-material direct manufacturing.

[0068] In another aspect, the method comprises providing an orthosis as in any embodiment herein.

[0069] In another aspect, a method for designing an orthodontic appliance for repositioning a patient's teeth according to a treatment plan is provided. The method may include receiving a 3D representation of a shell, the shell including a plurality of cavities shaped to accommodate the patient's teeth, the shell including a plurality of shell portions, each shell portion being positioned to engage a different subset of the patient's teeth. The method may include generating a 2D representation corresponding to the 3D representation of the shell, the 2D representation representing a sheet of material to be used to form the shell. The sheet of material may include a plurality of sheet portions corresponding to the plurality of shell portions.

[0070] In some embodiments, the 2D expression is generated based on one or more of the cavity geometry for the plurality of cavities, the manufacturing method for forming the shell, the manufacturing temperature for forming the shell, the one or more materials for forming the shell, the material properties of the one or more materials for forming the shell, or the strain rate of the one or more materials for forming the shell. The 2D expression can be generated by converting the 3D expression, the conversion including one or more of expanding or flattening the 3D expression. The 2D expression can be generated by simulating a direct deformation or an inverse deformation from the 2D expression to the 3D expression.

[0071] In some embodiments, the method further comprises determining a material composition for each of the plurality of sheet portions. At least some of the plurality of sheet portions may comprise different material compositions. The method may further comprise generating instructions for manufacturing a sheet of material comprising the plurality of sheet portions having the determined material composition, and generating instructions for forming a shell from the manufactured sheet of material. In some embodiments, the inner shell comprises a tooth-facing surface, and an outer surface of the outer shell is exposed.

[0072] In some embodiments, at least some of the plurality of different sheet portions have different geometries. At least some of the plurality of different sheet portions may have different stiffnesses. The method may also include determining a desired stiffness for each of the plurality of sheet portions, and determining a material composition for each of the plurality of sheet portions based on the desired stiffness. The different material compositions may include one or more of: different numbers of material layers, different combinations of material types, or different thicknesses of material layers.

[0073] In some embodiments, the manufactured material sheet includes an outer layer and an inner layer, the inner layer having a stiffness less than the stiffness of the outer layer, and when the shell is worn on the patient's teeth, the inner layer is positioned between the outer layer and the patient's teeth. Different material compositions can include inner layers of different thicknesses. When the shell is worn on the patient's teeth, the outer layer can be configured to generate at least one force or torque, and the inner layer can be configured to distribute the at least one force or torque to at least one accommodated tooth.

[0074] In some embodiments, manufacturing the material sheet includes providing a first material layer and adding a second material to one or more portions of the layer. Alternatively or in combination, manufacturing the material sheet may include providing a sheet including a first material layer and a second material layer and removing one or more portions of the second material layer. Optionally, manufacturing the material sheet includes joining a plurality of overlapping material layers to form a multilayer material sheet. Manufacturing the material sheet may include joining a plurality of non-overlapping material portions to form a single-layer material sheet. Manufacturing the material sheet may include joining one or more support layers to the single-layer material sheet.

[0075] In some embodiments, forming the shell includes thermoforming the fabricated sheet of material on a mold such that the plurality of sheet portions are formed into the plurality of shell portions.

[0076] In another embodiment, a system for designing an orthodontic appliance for repositioning a patient's teeth according to a treatment plan is provided. The system may include one or more processors and a memory. The memory may include instructions executable by the one or more processors to cause the system to receive a 3D representation of a shell, the shell including a plurality of cavities shaped to accommodate the patient's teeth, the shell including a plurality of shell portions, each of the shell portions being positioned to engage a different subset of the patient's teeth. The instructions may cause the system to generate a 2D representation corresponding to the 3D representation of the shell, the 2D representation representing a sheet of material used to form the shell, and the sheet of material including a plurality of sheet portions corresponding to the plurality of shell portions.

[0077] In another embodiment, a method for designing an orthodontic appliance for repositioning a patient's teeth is provided. The method may include determining a movement path for moving one or more teeth from an initial arrangement to a target arrangement, and determining a force system for producing movement of one or more teeth along the movement path. The method may include determining an appliance geometry of an orthodontic appliance configured to produce a force system. The orthodontic appliance may include: an outer shell including a plurality of tooth-accommodating cavities; and an internal structure positioned on an inner surface of the outer shell, the internal structure including a stiffness different from the stiffness of the outer shell, such that the internal structure is configured to present a deformation greater than the deformation presented by the outer shell. The method may include generating instructions for using a manufacturing technique to manufacture an orthodontic appliance having an appliance geometry.

[0078] In some embodiments, the fabrication technique is a direct fabrication technique.

[0079] In some embodiments, the direct manufacturing technology includes one or more of slot photocuring, material jetting, binder jetting, material extrusion, powder bed fusion, sheet lamination, or directed energy deposition, and can be a continuous direct manufacturing process, multi-material direct manufacturing, or other direct manufacturing process. The instructions can be configured to cause the manufacturing machine to simultaneously form the outer shell and the internal structure.

[0080] In some embodiments, the method further includes determining a material composition for one or more of the outer shell or the inner structure.

[0081] In another aspect, an appliance for placing an attachment on a patient's teeth is provided. The appliance may include an attachment and a support. The support may include one or more attachment structures to hold the attachment. The appliance may also include one or more alignment structures attached to the support to accommodate at least a portion of the tooth and place the attachment at a predetermined position on the tooth. The one or more attachment structures may be configured to release the attachment when the alignment structure is removed from the tooth.

[0082] In some embodiments, the calibration structure includes: at least a cavity portion of the aligner, which is sized and shaped to accommodate the tooth; and a support member, which includes an aligner portion extending from the cavity portion to a recess. The recess is shaped to accommodate an accessory and includes one or more connecting structures to retain the accessory, and wherein at least the cavity portion of the aligner and the aligner portion extending from at least the cavity portion to the recess have been directly manufactured together. Optionally, the one or more connecting structures include one or more extensions extending between the support member and the accessory. The one or more extensions can absorb infrared light at a greater rate than the calibration structure.

[0083] In some embodiments, the aligner includes an adhesive on the attachment and may also include a cover on the adhesive. The cover is removable from the adhesive.

[0084] In another aspect, a method of manufacturing an orthodontic appliance is provided. The method may include directly manufacturing an aligner body including a support formed in a tooth receiving cavity. The tooth receiving cavity may be configured to receive a tooth. The method may also include manufacturing one or more attachment structures directly to the support, and manufacturing an attachment directly to the attachment structure. The aligner may be configured to align the attachment at a predetermined position on the tooth, and the one or more attachment structures may be configured to release the attachment when the aligner body is removed from the tooth.

[0085] In some embodiments, the support, the aligner body, and the one or more attachment structures are manufactured directly together. Optionally, the alignment structure may include: at least a portion of a cavity of the aligner, which is sized and shaped to accommodate one or more teeth, and the support may include a portion of the aligner, which includes a recess shaped to accommodate an accessory. The recess may include one or more attachment structures to hold the accessory, and the aligner body, the one or more attachment structures, and the recess may be manufactured directly together.

[0086] In some embodiments, the one or more attachment structures are configured to break when the alignment structure is removed from the one or more teeth. Optionally, the one or more attachment structures may be sized and shaped to retain the attachment. The one or more attachment structures may be sized and shaped to retain the attachment via a gap extending between the support and the attachment.

[0087] In some embodiments, the one or more attachment structures include one or more extensions extending between the support and the accessory. The one or more attachment structures may include a separator sized and shaped to separate the accessory from the support. The one or more attachment structures may include a recess formed in the support sized and shaped to separate the accessory from the support.

[0088] In some embodiments, the method may include forming an adhesive structure on the accessory. Alternatively, the method may include forming an adhesive on one or more accessories, wherein the adhesive, one or more coupling structures, the alignment structure and the one or more attachment structures are directly manufactured together.

[0089] In some embodiments, the method may include forming a cover on the adhesive, the cover being removable from the adhesive. The cover, adhesive, support, one or more linking structures, calibration structure, and one or more attachment structures may be manufactured directly together. One or more extensions may be formed of a material that absorbs infrared light at a rate greater than the infrared absorption rate of the calibrator body.

[0090] As used herein, the term "and / or" is used as a function word to indicate that two words or phrases are performed together or separately. For example, A and / or B includes A alone, B alone, and A and B together.

[0091] Turning now to the drawings, in which like reference numerals represent like elements throughout the different drawings, Figure 1AAn exemplary tooth repositioning brace or aligner 100 is shown that can be worn by a patient to achieve incremental repositioning of a single tooth 102 in a jaw. The brace can include a shell (e.g., a continuous polymer shell or a segmented shell) having a tooth-receiving cavity that receives and elastically repositions the tooth. In one embodiment, the brace or one or more portions thereof can be indirectly manufactured using a physical model of the teeth. For example, the brace (e.g., a polymer brace) can be formed using a physical model of the teeth and a sheet of a suitable polymer material layer. In some embodiments, the physical brace is directly manufactured from a digital model of the brace, for example using direct manufacturing techniques. The brace can be fitted over all teeth present in the maxillary or mandibular, or less than all teeth. The brace can be specifically designed to accommodate the patient's teeth (e.g., the topography of the tooth-receiving cavity matches the topography of the patient's teeth), and can be manufactured based on a positive or negative mold of the patient's teeth generated by an impression, a scan, or the like. Alternatively, the appliance may be a universal appliance that is constructed to accommodate teeth, but is not necessarily shaped to match the topography of the patient's teeth. In some cases, only specific teeth accommodated by the appliance will be repositioned by the appliance, while other teeth may provide a base or anchoring area for holding the appliance in place because the appliance applies force to one or more teeth targeted for repositioning. In some cases, many teeth, a majority of teeth, or even all of the teeth will be repositioned at some point during treatment. The teeth being moved may also serve as a base or anchor for holding the appliance as it is worn by the patient. Typically, no wire or other device will be provided for holding the appliance in place on the teeth. However, in some cases, it may be desirable or necessary to provide a separate attachment or other anchoring element 104 on the tooth 102 and to have a corresponding receptacle or aperture 106 in the appliance 100 so that the appliance can apply a selected force on the tooth. Including Exemplary aligners such as those used in the system are described in numerous patents and patent applications assigned to Align Technology, Inc., including, for example, U.S. Pat. Nos. 6,450,807 and 5,975,893, and on the company's website, which is accessible on the World Wide Web (see, for example, the URL "invisalign.com"). Examples of tooth-mounted attachments suitable for orthodontic aligners are also described in patents and patent applications assigned to Align Technology, Inc., including, for example, U.S. Pat. Nos. 6,309,215 and 6,830,450.

[0092] Figure 1BA tooth repositioning system 110 is shown that includes a plurality of aligners 112, 114, 116. Any of the aligners described herein may be designed and / or configured as part of a set of a plurality of aligners for use in a tooth repositioning system. Each aligner may be configured such that a tooth receiving cavity has a geometry corresponding to an intermediate or final tooth arrangement for the aligner. By placing a series of incremental position adjustment aligners on the patient's teeth, the patient's teeth may be gradually repositioned from an initial tooth arrangement to a target tooth arrangement. For example, the tooth repositioning system 110 may include: a first aligner 112, corresponding to an initial tooth arrangement; one or more intermediate aligners 114, corresponding to one or more intermediate arrangements; and a final aligner 116, corresponding to a target arrangement. The target tooth arrangement may be a planned final tooth arrangement selected for the patient's teeth at the end of all planned orthodontic treatment. Additionally, a target arrangement can be one of many intermediate arrangements of a patient's teeth during the course of orthodontic treatment, which can include a variety of different treatment situations, including, but not limited to, for example, when surgery is recommended, when interproximal reduction (IPR) is appropriate, when a progress check is scheduled, when anchor placement is optimal, when palate expansion is required, when restorative dentistry (e.g., inlays, onlays, crowns, bridges, implants, veneers, etc.) is involved, and the like. For example, it should be understood that a target tooth arrangement can be any planned final (result) arrangement of a patient's teeth after one or more incremental repositioning stages. Likewise, an initial tooth arrangement can be any initial arrangement of a patient's teeth followed by one or more incremental repositioning stages.

[0093] Figure 2A method 200 of orthodontic treatment using multiple appliances according to many embodiments is shown. The method 200 can be practiced using any appliance or appliance set described herein. In step 210, a first orthodontic appliance is applied to the patient's teeth so as to reposition the teeth from a first tooth arrangement to a second tooth arrangement. In step 220, a second orthodontic appliance is applied to the patient's teeth so as to reposition the teeth from a second tooth arrangement to a third tooth arrangement. The method 200 can be repeated as needed using any suitable number and combination of sequential appliances so as to incrementally reposition the patient's teeth from an initial arrangement to a target arrangement. The appliances can be generated in whole or in groups or batches (e.g., at the beginning of treatment) at the same stage, or one at a time, and the patient can wear each appliance until the pressure of each appliance on the teeth can no longer be felt, or until the maximum amount of tooth movement expressed for the given stage has been reached. A plurality of different braces (e.g., a set) can be designed and even manufactured before the patient wears any of the braces in the plurality of braces. After wearing the braces for an appropriate period of time, the patient can replace the current braces with the next brace in the series until there are no more braces left. The braces are usually not attached to the teeth, and the patient can place and replace the braces at any time during the process (e.g., patient-removable braces). The final brace or some braces in the series may have one or more geometries that are selected to overcorrect the tooth arrangement. For example, the geometry of one or more braces can move individual teeth (if fully realized) beyond the tooth arrangement that has been selected as "final". In order to offset potential relapse after the repositioning method has been terminated (e.g., allowing individual teeth to move back toward their pre-corrected positions), this overcorrection may be in line with the desired. Overcorrection is also beneficial to speed up the correction speed (e.g., braces with geometries that are positioned beyond the desired intermediate position or final position can move each tooth toward that position at a greater speed). In this case, the use of the braces can be terminated before the teeth reach the position defined by the braces. In addition, overcorrection can be deliberately applied to compensate for any inaccuracies or limitations of the braces.

[0094] The ability of an orthodontic appliance to effectively treat a patient's teeth may depend on its properties, such as stiffness, elastic modulus, hardness, thickness, strength, or compressibility. For example, these properties may affect the amount of force and / or torque that the appliance can apply to the teeth, and the degree to which such force and / or torque can be controlled (e.g., about the position, direction, size, etc. of application). The optimal properties for tooth repositioning may vary based on the type of tooth to be repositioned (e.g., molars, premolars, canines, incisors), the type of movement (e.g., extrusion, intrusion, rotation, torsion, tilt, translation), the target movement distance, the use of attachments installed on the teeth, or a combination thereof. Different teeth in the patient's jaw may also require different types of appliance properties to be effectively repositioned. In some cases, it may be relatively difficult to effectively reposition multiple teeth using an orthodontic appliance with consistent and / or similar properties.

[0095] Therefore, various embodiments of the present disclosure provide an orthodontic appliance with heterogeneous and / or varying properties between different parts of the appliance to allow for more efficient repositioning of multiple teeth. In such embodiments, one or more parts of the appliance may have one or more properties different from one or more other parts, such as one or more properties of properties such as stiffness, elastic modulus, hardness, thickness, strength, compressibility, etc. The appliance may include any number of parts with different properties, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50 or more parts with different properties. The appliance portion may include any part of the appliance, such as one or more teeth accommodating cavities or portions thereof. The size and position of the appliance portion may be changed as needed. For example, the appliance portion may be arranged to accommodate and / or engage a subset of the patient's teeth, such as a single tooth, multiple teeth, a portion of a tooth (e.g., lingual, buccal or occlusal surface), or a combination thereof. In some embodiments, portions of the appliance that accommodate different subsets of teeth (e.g., front teeth, back teeth, teeth to be repositioned, teeth to be retained in their current positions) have different properties. Alternatively or in combination, portions of the appliance that engage different surfaces of the teeth (e.g., buccal, lingual, occlusal) can have different properties. As further described herein, the use of an orthodontic appliance with variable local properties can allow for improved control of the forces and / or torques applied to the patient's teeth.

[0096] In some embodiments, orthodontic appliances with different local properties are made of a variety of different materials. The appliance can be made of one or more of a variety of materials such as plastics, elastomers, metals, glass, ceramics, reinforced fibers, carbon fibers, composite materials, reinforced composite materials, aluminum, biomaterials, or a combination thereof. The material can be incorporated into the orthodontic appliance in any form such as a layer, a pad, a strip, a band, a wire, a net, a bracket, or a combination thereof. In some embodiments, the appliance can include at least two, three, four, five, six, seven, eight, nine or ten different types of materials. Different material types can present different properties (e.g., stiffness, elastic modulus, etc.). The appliance comprising a variety of materials can include different materials in different parts of the appliance, thereby providing a desired combination with different local properties. An exemplary method for manufacturing an appliance with a variety of materials will be further described herein.

[0097] Alternatively, an orthodontic appliance may include only a single material type, but the properties of the single material may be changed to achieve different local properties. For example, different local stiffnesses may be achieved by changing the thickness and / or number of layers of the material at different appliance portions. Alternatively or in combination, the geometry of the material may be selectively changed at certain locations to change the corresponding properties of the appliance at that location, such as selectively forming cutouts or holes to reduce stiffness. These schemes may be used in conjunction with the multi-material schemes described herein so that different local properties may be achieved by changing the type of material used and the properties of one or more material types.

[0098] In some embodiments, an orthodontic appliance includes at least one relatively rigid portion and at least one relatively compliant portion. "Rigid" or "relatively rigid" may be used herein to refer to an appliance portion whose rigidity is greater than the rigidity of another appliance portion, such as the remainder of the appliance. "Compliant" or "relatively compliant" may be used herein to refer to an appliance portion whose rigidity is less than the rigidity of another appliance portion, such as the remainder of the appliance. The appliance herein may be manufactured using one or more types of materials (e.g., synthetic materials, such as plastics, ceramics, metals, composite materials; biological materials, such as biological tissues, natural materials) with appropriate properties to provide the desired arrangement of rigid and compliant portions. For example, one or more rigid portions may be made of one or more relatively rigid materials, and one or more compliant portions may be made of one or more relatively compliant materials. Examples of rigid materials include, but are not limited to, plastics, ceramics, metals, composite materials, or combinations thereof (e.g., plastics filled with ceramics and / or reinforced with metal sheets). Examples of compliant materials include, but are not limited to, elastomers, rubbers, or rubber-like materials.

[0099] The elastic modulus of the rigid portion may be greater than that of the compliant portion. In some embodiments, the rigid portion has an elastic modulus of about 1.5 GPa, or an elastic modulus in the range of about 0.5 GPa to about 500 GPa. In some embodiments, the compliant portion has an elastic modulus of about 2 MPa, or an elastic modulus in the range of about 0.2 MPa to about 500 MPa. Optionally, the elastic modulus of the rigid portion may be at least 10 times greater than the elastic modulus of the compliant portion. The high modulus difference between the layers can increase the shear force at the boundaries between the layers. In some embodiments, the shear between the layers can be managed by using materials in adjacent layers with elastic moduli that differ by 10% or less. Alternatively or in combination, the thickness of the rigid portion may be greater than that of the compliant portion. For example, the rigid portion may have a thickness of about 0.5 mm, or a thickness in the range of about 0.2 mm to about 1 mm. The compliant portion may have a thickness of about 0.3 mm, or a thickness in the range of about 0.05 mm to about 0.5 mm. Optionally, the thickness of the rigid portion may be at least 3 times greater than the thickness of the compliant portion.

[0100] Rigid parts and compliant parts can perform different functions in an orthodontic appliance. For example, a rigid part can be used to generate a force and / or torque to reposition a tooth, for example, by pressing against one or more regions of a tooth. In some embodiments, the shape of the appliance is designed so that when the appliance is worn on the tooth, the rigid part is deformed (e.g., shape changes) and / or deflected (e.g., changed in position, orientation), and the resistance of the rigid material to be deformed and / or deflected generates a force and / or torque on the tooth that causes the tooth to move. The rigid part can have sufficient rigidity so that different regions can be deformed and / or deflected independently relative to each other (e.g., a deformation and / or deflection of one region produces little or no corresponding deformation and / or deflection in an adjacent region). In some embodiments, the rigid part is relatively resistant to deformation, so that when the appliance is worn on the tooth, the rigid part can be deflected, but exhibits little deformation or no deformation. Optionally, the rigid part can be relatively incompressible so that it does not experience significant changes in shape (e.g., thickness) when the appliance is worn.

[0101] The compliant portion can be used to transfer the force and / or torque generated by the rigid portion to the underlying teeth. For example, the compliant portion can be positioned between the rigid portion and the teeth (e.g., connected to the inner surface of the rigid portion facing the teeth) so as to contact the teeth and distribute the force and / or torque from the rigid portion to the teeth. In some embodiments, the compliant portion is designed to improve the transmission of force and / or torque to the teeth compared to using only the rigid portion. For example, the compliant portion can improve the engagement between the brace and the teeth, provide a more constant amount of force and / or torque, distribute the force and / or torque over a wider surface area, or a combination thereof. Optionally, the compliant portion can be relatively deformable (e.g., compressible) so as to exhibit a significant change in shape (e.g., thickness) when the brace is worn.

[0102] The rigid and compliant portions of an orthodontic appliance can be designed in various ways. In some embodiments, the rigid portion is an outer appliance shell having a plurality of cavities formed to accommodate teeth, and the compliant portion includes one or more internal structures (e.g., the inner surface of one or more tooth-accommodating cavities) attached to the inner surface of the shell. One or more compliant internal structures may be removably attached or permanently attached to the outer shell (e.g., via adhesives, fasteners, bonding, etc.). As described herein, the rigidity of the rigid outer shell may be different from, for example, greater than the rigidity of the compliant internal structure.

[0103] The rigid outer shell can be shaped to generate one or more forces and / or torques in response to the braces being worn on the patient's teeth. For example, the outer shell can have an inner surface profile (e.g., the inner surface profile of one or more tooth-receiving cavities) that is different from the surface profile of one or more received teeth (e.g., received in one or more tooth-receiving cavities). For example, the inner surface profile of the outer shell can have a position and / or orientation different from the surface profile of the teeth. Alternatively or in combination, the inner surface profile of the outer shell can include structures that do not match the surface profile of the teeth, such as a protrusion extending toward the teeth or a recess extending away from the teeth. The difference between the inner surface profile of the outer shell and the surface profile of the teeth can cause deflection and / or deformation of the outer shell, and the deflection and / or deformation of the outer shell produces a force and / or torque applied to the teeth.

[0104] A compliant internal structure can be positioned between the outer shell and one or more received teeth to distribute forces and / or torques generated by the outer shell to the teeth. For example, the internal structure can deform in response to the forces and / or torques, for example by exhibiting changes in thickness and / or inner surface profile. Alternatively, the internal structure can deform so that the inner surface profile conforms to the surface profile of the teeth, thereby increasing the degree of engagement between the appliance and the tooth surface. Such improved engagement can improve the transmission of forces and / or torques from the outer shell to the teeth, for example by increasing the tooth surface area to which the forces and / or torques are applied.

[0105] Using a compliant internal structure to distribute the force and / or torque from the rigid outer shell can reduce the sensitivity of the orthodontic appliance to changes in manufacturing tolerances. In some embodiments, the geometry of the appliance shell is constructed to be different from the geometry of the patient's current tooth arrangement, and the engagement between the shell and the teeth caused by this geometric mismatch (also known as "conflict") causes force and / or torque to be applied to the teeth. The magnitude of the force and / or torque can be related to the degree of conflict between the shell geometry and the tooth geometry, so that the portion of the appliance that presents a larger amount of conflict applies a larger amount of force and / or torque, while the portion that presents a smaller conflict or no conflict applies a smaller force and / or torque or does not apply force and / or torque. Therefore, the appliance geometry can be designed to present a certain amount of conflict with the tooth geometry in order to generate the desired force and / or torque for repositioning the teeth. In embodiments where the appliance shell is relatively rigid, deviations from the planned appliance geometry (e.g., due to changes in manufacturing tolerances) can change the amount of conflict between the rigid shell and the teeth, which in turn can change the amount of force and / or torque actually applied to the teeth.

[0106] The use of a compliant structure with a rigid outer shell can reduce the sensitivity of the brace geometry to such changes. In some embodiments, the compliant structure is less susceptible to fluctuations in the applied force and / or torque due to manufacturing tolerances than a more rigid structure. For example, the amount of force and / or torque applied to the teeth by the compliant structure (e.g., due to the lower stiffness of the compliant structure) can be less dependent on the degree of conflict between the compliant structure and the teeth. In order to produce the same degree of force as a fully rigid brace, the braces with a compliant structure herein can be designed to have an increased amount of conflict with the tooth geometry. Therefore, an orthodontic brace incorporating a compliant structure can produce a more consistent and repeatable force and / or torque to be applied to the teeth. In addition, such a compliant structure can provide a more constant force applied to the teeth as it moves during treatment.

[0107] Figure 3A and Figure 3BA portion 300 of an orthodontic appliance is shown including a rigid outer shell 302 and a compliant inner structure 304 according to various embodiments. Figure 3A The aligner portion 300 is shown in an unloaded configuration prior to being placed on a patient's teeth such that both the outer shell 302 and the inner structure 304 are in a free state and the shape profiles of the outer shell 302 and the inner structure 304 are undistorted. For example, the compliant inner structure 304 (shown here as a layer) can have an initial thickness profile 306, while the rigid outer shell 302 can have an initial thickness profile 307. In some embodiments, the undistorted shape profiles of the outer shell 302 and / or the inner structure 304 can correspond to the 3D shape profile of the teeth in an unloaded position and / or orientation prior to being received within the aligner portion 300.

[0108] Figure 3B The aligner portion 300 is shown after being placed on the patient's teeth. The portion 300 can engage the tooth 308 so that the inner surface of the inner structure 304 contacts the surface of the tooth 308. The inner surface profiles of the inner structure 304 and the outer shell 302 can be different from the surface profiles of the tooth 308, which allows the aligner portion 300 to press against and apply force to the tooth 308 when the aligner is worn. The rigid outer shell 302 can have sufficient rigidity so that it undergoes little or no deformation when pressed against the tooth 308, for example, the thickness profile 307 is substantially unchanged.

[0109] In contrast, the compliant inner structure 304 is sufficiently compliant such that it deforms when pressed against the tooth 308. In some embodiments, when the aligner is worn on the patient's teeth, the compliant inner structure 304 exhibits a greater amount of deformation than the outer shell exhibits. Accordingly, when the aligner portion 300 is worn by the patient, the inner structure 304 can be assumed to be in a loaded configuration (e.g., with respect to the thickness profile, cross-sectional shape, and / or inner surface profile of the inner structure 304) that is different from the unloaded configuration. For example, the inner structure 304 can be compressed between the rigid outer shell 302 and the tooth 308, thereby exhibiting a varying (e.g., decreasing) thickness profile 310 at the junction area. In some embodiments, those portions of the inner structure 304 that are proximate to the junction area between the inner structure 304 and the tooth 308 are extruded outwardly from the junction area, such that the thickness profile, inner surface profile, and cross-sectional shape of the inner structure 304 are changed relative to the unloaded configuration. The profile of the twisted shape can correspond to the 3D shape profile of the tooth 308 (when the tooth is in an accommodated position and / or orientation within the appliance portion 300). The change in the thickness profile of the internal structure 304 can correspond to the difference between the unloaded position and / or orientation of the tooth 308 and the accommodated position and / or orientation of the tooth 308. Optionally, the internal structure 304 can deform to conform to the surface contour of the tooth at the engagement area. The stiffness of the outer shell 302 can cause forces and / or torques to be generated on the tooth 308, while the compliance of the internal structure 304 can allow for improved engagement between the appliance portion 300 and the tooth 308 so as to distribute the generated forces and / or torques to the tooth 308.

[0110] The compliant internal structure described herein can be provided in various forms, such as layers, pads, strips, bands, wires, meshes, brackets, or combinations thereof. As further described herein, the internal structure can be formed by milling, etching, coating, spraying, printing, bonding, spraying, extrusion, deposition, or combinations thereof. In some embodiments, the internal structure is a single continuous structure such as a layer. For example, the internal structure can be a continuous layer overlapping the inner surface of the rigid outer shell. The compliant inner layer can span some or all of the multiple cavities of the outer shell. In such embodiments, the orthodontic braces can be considered to be a multilayer brace having a rigid outer layer and a compliant inner layer.

[0111] Figure 3CAn appliance portion 320 is shown having a compliant tooth surface or inner structure 324 (here shown as a layer) and a compliant outer structure 326, while having a rigid intermediate layer 322 (also referred to as a shell). The portion 320 can engage the tooth such that the inner surface of the inner structure 324 contacts the surface of the tooth. The inner surface profiles of the inner structure 324 and the intermediate shell 322 can be different from the surface profile of the tooth, which allows the appliance portion 320 to press against and apply force to the tooth when the appliance is worn. The rigid intermediate shell 322 can be sufficiently rigid that it undergoes little or no deformation when pressed against the tooth, for example, the thickness profile is substantially unchanged.

[0112] In contrast, the compliant inner structure 324 is sufficiently compliant (like the inner structure 304) so ​​that it deforms when pressed against the teeth. In some embodiments, when the aligner is worn on the patient's teeth, the compliant inner structure 324 exhibits a greater amount of deformation than the intermediate shell 322 exhibits. Thus, when the aligner portion 320 is worn by the patient, the inner structure 324 can be assumed to be in a loaded configuration (e.g., with respect to the thickness profile, cross-sectional shape, and / or inner surface profile of the inner structure 324) that is different from the unloaded configuration. For example, the inner structure 324 can be compressed between the rigid intermediate shell 322 and the teeth, thereby exhibiting a varying (e.g., decreasing) thickness profile in the engagement region. In some embodiments, those portions of the inner structure 324 that are proximal to the engagement region between the inner structure 324 and the teeth are squeezed outwardly from the engagement region, such that the thickness profile, inner surface profile, and cross-sectional shape of the inner structure 324 change relative to the unloaded configuration. The profile of the distorted shape can correspond to the 3D shape profile of the teeth (when the teeth are in the accommodated position and / or orientation within the aligner portion 320). The change in the thickness profile of the internal structure 324 can correspond to the difference between the unloaded position and / or orientation of the tooth and the accommodated position and / or orientation of the tooth. Optionally, the internal structure 324 can be deformed to conform to the tooth surface profile at the engagement area. The rigidity of the intermediate shell 322 can cause forces and / or torques to be generated on the teeth, while the compliance of the internal structure 324 can allow improved engagement between the aligner portion 320 and the teeth so as to distribute the generated forces and / or torques to the teeth and reduce the sensitivity to the magnitude of forces and torques caused by manufacturing tolerances. For example, the conflict between the aligner and the teeth causes torques and forces involved in moving the teeth. The elasticity of the aligner material and the rigidity of the aligner cause these forces. Small differences in the manufactured shape of the aligner compared to the desired shape of the aligner can result in deviations from the desired forces and torques applied to the teeth. For rigid aligners, errors in manufacturing are greater than for more compliant aligners. The addition of a compliant internal structure can reduce the sensitivity of force and torque magnitudes due to manufacturing tolerances while still maintaining many of the advantages of rigid aligners, such as the ability to apply higher forces and torques on the teeth.

[0113] The addition of the compliant outer structure 326 may provide a more comfortable experience for the patient because the compliant outer structure 326 may deform when in contact with the gums, soft palate, hard palate, cheeks, and other parts of the patient's mouth.

[0114] Figure 4AA cross-section of an orthodontic appliance 400 having a rigid outer layer 402 and a compliant inner layer 404 is shown according to various embodiments. As described herein, the outer layer 402 forms a shell having a plurality of cavities 406 for receiving the patient's teeth. The inner layer 404 is attached to the inner surface of the outer layer 402 such that the inner layer 404 overlaps some or all of the cavities and is positioned between the outer layer 402 and the received teeth. In some embodiments, when the appliance 400 is worn on the teeth, the received teeth contact the inner layer 404 and do not directly contact the outer layer 402.

[0115] The properties of the inner and outer layers can be changed as desired. In some embodiments, the inner and outer layers have the same thickness, while in other embodiments, the inner and outer layers have different thicknesses. For example, the thickness of the outer layer can be about 0.5 mm, or in the range of about 0.1 mm to about 2 mm, and the thickness of the inner layer can be about 0.5 mm, or in the range of about 0.1 mm to about 2 mm. Optionally, the total thickness of the brace including the outer and inner layers can be less than or equal to about 0.8 mm (e.g., to avoid causing an open bite if the brace covers the occlusal area of ​​the crown). In some embodiments, each layer has a uniform thickness, while in other embodiments, one or more layers may have a non-uniform thickness (e.g., different layer portions have different thicknesses).

[0116] In some embodiments, the inner layer and / or the outer layer may include a force modification structure that adjusts the local force and / or torque applied to a specified location on the patient's teeth, either directly (e.g., by directly contacting the tooth surface) or indirectly (e.g., by contacting an attachment mounted on the tooth). The force modification structure may include any structural feature that produces a change in the force and / or torque applied to the tooth, such as a thickened portion, a thinned portion, a protrusion (e.g., a ridge, a dimple, and a depression), a recess, an aperture, a gap, or a combination thereof. For example, when the brace is worn, a thickened portion or a protrusion that is compressed by the teeth can produce a locally increased force and / or torque. A thinned portion or a recess can exhibit reduced contact with the teeth, thereby producing a locally reduced force and / or torque. Use of a force modification structure as described herein allows for increased control of the force and / or torque applied to a specified location on the teeth.

[0117] The appliance may include any number and combination of force modification structures located on the inner layer and / or the outer layer. In some embodiments, the force modification structures are located only on the inner layer or only on the outer layer, so that the two layers have different geometries. For example, the inner layer may include one or more portions of increased thickness that are designed to preferably engage the teeth to apply force and / or torque. Alternatively or in combination, the inner layer may include one or more portions of reduced thickness that reduce the local engagement of the appliance with the teeth. As another example, the outer layer may be formed with one or more protrusions that extend into the tooth receiving cavity to engage the teeth and apply force and / or torque to the teeth. Alternatively or in combination, the outer layer may be formed with one or more recesses or gaps to reduce the amount of force and / or torque to be applied. Optionally, the layer that does not include the force modification structure may have a uniform thickness.

[0118] Figure 4B A cross-section of an orthodontic appliance 410 having a compliant inner layer 412 with a thickened portion 420 is shown according to various embodiments. The inner layer 412 is attached to the inner surface of a rigid outer layer 414, thereby defining a cavity 416 shaped to accommodate a tooth 418. The outer layer 414 may have a uniform thickness. The inner layer 412 may include a force modification structure, such as at least one layer portion 420 having an increased thickness relative to other portions of the inner layer 412. The thickened portion 420 may be positioned to engage the accommodated tooth 418. Due to the increased thickness of the layer portion 420, the portion 420 may be pressed against the rigid outer layer 414 by the tooth 416 when the tooth 418 is accommodated in the cavity 416. This arrangement may result in force and / or torque being applied to the tooth 418 primarily at the thickened layer portion 420. Multiple thickened portions may be included in the inner layer 412 to help apply force and / or torque at multiple different portions of the tooth 418. although Figure 4B An inner layer 412 having a non-uniform thickness and an outer layer having a uniform thickness are shown, but it will be appreciated by those skilled in the art that other embodiments may include an outer layer having a non-uniform thickness and an inner layer having a uniform thickness. In alternative embodiments, both the inner layer and the outer layer may have a non-uniform thickness.

[0119] Figure 4CA cross-section of an orthodontic brace 430 is shown including a protrusion 432 formed in a rigid outer layer 434 according to multiple embodiments. Similar to other embodiments herein, the brace 430 can include a rigid outer layer 434 coupled to a compliant inner layer 436, thereby defining a cavity 438 shaped to accommodate a tooth 440. Both the outer layer 434 and the inner layer 436 can have a uniform thickness. In some embodiments, the rigid outer layer 434 includes a force-modifying structure, such as a protrusion 432 extending inwardly toward the tooth 440 into the cavity 438. The inner layer 436 can conform to the inner surface contour of the outer layer 434 including the protrusion 432. The protrusion 432 can be pressed against the surface of the accommodated tooth 440 to apply force and / or torque to the tooth. Optionally, the brace 430 can include multiple protrusions 432 in the outer layer 434 to help apply force and / or torque to multiple different portions of the tooth 440. Although Figure 4C The protrusions 432 are shown to be located in the outer layer 434, but those skilled in the art will appreciate that other embodiments may include protrusions located in the inner layer, or protrusions located in both the outer layer and the inner layer.

[0120] In some embodiments, the rigid outer layer and the compliant inner layer are removably connected to each other so that the outer layer and the inner layer can be separated from each other without damaging the brace. For example, the removable connection can be a snap fit or an interference fit. In such an embodiment, the inner layer can be considered to be an inner shell, the outer layer can be considered to be an outer shell, and the two shells can be separated from each other. In order to assemble the brace, the inner shell can be placed on the patient's teeth, and then the outer shell is placed on the inner shell and placed on the teeth. Alternatively, the inner shell can be inserted into the outer shell, and the assembled brace is placed on the teeth as a single component. By using a removably connected inner shell and outer shell, it is possible to allow a single inner shell and multiple outer shells, a single outer shell and multiple inner shells, or a combination thereof to be used in a treatment system. The inner shell and / or outer shell to be used can vary based on the specific treatment stage so that the patient can wear different combinations of multiple shells throughout the treatment process.

[0121] Figure 4DA treatment system 450 including a plurality of rigid outer shells 452a-452c and a single compliant inner shell 454 is shown according to multiple embodiments. A single outer shell can be worn on the inner shell 454 to form an orthodontic appliance. The rigid outer shells 452a-452c can be shaped to generate tooth repositioning forces and / or torques, while the compliant inner shell 454 can be primarily used as a liner that engages the teeth to distribute the generated forces and / or torques to the teeth. In some embodiments, each outer shell corresponds to a different treatment phase of the treatment plan, so that the outer shells 452a-452c are worn sequentially to reposition the teeth according to the treatment plan. For example, the geometry of the cavity of each outer shell can be shaped according to the specific tooth arrangement to be achieved in the corresponding treatment phase. The inner shell 454 can be reused between treatment phases, so that the patient can simply enter the next phase by sequentially exchanging the current outer shell with the next outer shell while keeping the same inner shell 454. In an alternative embodiment, multiple compliant inner shells can be used with a single reusable rigid outer shell, with each compliant inner shell corresponding to a different treatment phase. One of ordinary skill in the art will appreciate that an orthodontic treatment system can include any combination of a reusable outer shell and inner shell, respectively, combined with a non-reusable inner shell and outer shell, to achieve a desired treatment course.

[0122] In some embodiments, the rigid outer layer and the compliant inner layer are permanently attached to each other so that the layers cannot be separated without damaging the appliance. Benefits of this approach include easier handling and avoidance of warping or improper positioning when the inner layer wears under the outer layer. An orthodontic treatment plan may include sequentially applying a plurality of different multi-layer appliances to reposition the patient's teeth. Optionally, the treatment plan may include some stages of using appliances with permanently attached layers and some stages of using appliances with detachable shells.

[0123] Alternatively or in combination with the layer-based approach proposed herein, the compliant internal structure of an orthodontic appliance may include a plurality of discrete structures that are attached to portions of the outer shell. Examples of such structures include, but are not limited to, pads, plugs, balloons, bands, springs, brackets, nets, or combinations thereof. The appliance may include any number of discrete compliant structures located at any suitable location in the shell. Using one or more discrete internal structures located at different portions of the appliance, forces and / or torques can be controllably applied to selected portions of the teeth. The positioning, geometry (e.g., shape, size), and properties (e.g., stiffness, elastic modulus) of the discrete structures may be changed as desired to achieve desired force and / or torque distribution on the teeth.

[0124] Figure 5AAn appliance 500 is shown having a plurality of discrete spacer structures 502 according to various embodiments, which are attached to the inner surface of an outer shell 504. Similar to other embodiments herein, the outer shell 504 defines a tooth receiving cavity for a tooth 506. A plurality of discrete spacer structures 502 are positioned between the outer shell 504 and the tooth 506 so as to engage with the tooth 506. The spacer structures 502 may be solid. Alternatively, as further discussed herein, the spacer structures 502 may be hollow. In some embodiments, each spacer structure 502 engages a different portion of the tooth 506, such as a different tooth surface (e.g., buccal, lingual, or occlusal). The discrete spacer structures 502 may be configured to transfer forces and / or torques generated by the outer shell 504 to different portions of the tooth 506. In some embodiments, the spacer structures 502 are formed by printing or spraying onto the inner surface of the outer shell 504. Alternatively, the spacer structure 502 may be formed separately from and joined to the outer shell 504, such as using adhesives, fasteners, etc. In some embodiments, the spacer structure 502 and the outer shell 504 are formed using direct manufacturing, as discussed further herein.

[0125] Figure 5B An orthosis 520 is shown having a plurality of discrete plug structures 522 extending through an outer shell 524 according to various embodiments. Orthosis 520 is similar to orthosis 500, except that the discrete plug structures 522 each include an exterior portion extending through the thickness of the outer shell 524. In some embodiments, the plurality of discrete plug structures 522 are formed separately from the outer shell 524 and are attached to the outer shell 524, for example, using an adhesive, a fastener, or the like. Alternatively, the discrete plug structures 522 may be attached to the shell 524 using a mechanical retention means (e.g., an interference fit, a snap fit) without using an adhesive or other attachment element. Using a mechanical retention means may allow for increased flexibility in the geometry of the discrete plug structures 522. For example, the discrete plug structures 522 may be hollowed out (e.g., to control stiffness) without interfering with their ability to attach to the outer shell 524. In some embodiments, as further discussed herein, the plug structures 522 and the outer shell 524 are formed using direct manufacturing techniques.

[0126] Figure 5CAn appliance 540 is shown having a plurality of discrete hollow or inflatable structures 542 according to various embodiments. The inflatable structures 542 may be hollow balloons or pouches that may be filled with a fluid such as a liquid or a gas. Fluid pressure may be used to control the amount of force and / or torque applied by the appliance 540 to the received teeth 546. Optionally, the fluid may be maintained at a substantially constant pressure to allow a substantially constant force and / or torque to be applied to the teeth 546. Alternatively, the fluid pressure may produce a variable force and / or torque application on the teeth 546 as desired.

[0127] Figure 5D An exemplary load-displacement curve 560 for an appliance is shown in accordance with various embodiments. The load-displacement curve 560 exhibits a relatively flat region 562 in which the force or torque in the appliance is substantially constant, e.g., does not substantially vary with increasing displacement. In some embodiments, substantially constant means that the force or torque does not vary by more than 5%, 10%, 20%, 30%, 40%, or 50% of the maximum value of the force or torque over the travel distance of interest. As described herein, the use of discrete compliant internal structures can allow for the application of substantially constant forces and / or torques, which can improve the reliability and stability of orthodontic treatment with the appliance. For example, as described herein with respect to Figure 5C As described, one or more structures may be filled with a fluid maintained at a substantially constant pressure so as to apply a substantially constant force and / or torque to the tooth. Alternatively or in combination, the discrete pad structures may be manufactured in a shape and / or made of a suitable material to produce a substantially constant force and / or torque over a relatively large range of deflection and / or deformation without yielding (e.g., a polyolefin or a shape memory alloy such as NiT or Cu-Al-Ti).

[0128] Figure 5EAn appliance 570 having a plurality of discrete spacer structures 572 is shown according to multiple embodiments, which are attached to the inner surface of an outer shell 574. Similar to other embodiments herein, the outer shell 574 defines a tooth receiving cavity for a tooth 576. A plurality of discrete spacer structures 572 are positioned between the outer shell 574 and the tooth 576, thereby engaging the tooth 576. The spacer structures 572 can be solid. Alternatively, as further discussed herein, the spacer structures 572 can be hollow. In some embodiments, each spacer structure 572 engages a different portion of the tooth 576, such as a different tooth surface (e.g., buccal, lingual, or occlusal). The discrete spacer structures 572 can be configured to transmit and distribute the force and / or torque generated by the outer shell 574 to different portions of the tooth 576. In some embodiments, the spacer structures 572 are distributed around the surface of the outer shell 574 so that they distribute the repositioning force from the outer shell 574 to the tooth 576. In some embodiments, the spacer structure 572 is formed by printing or spraying on the inner surface of the outer shell 574. Alternatively, the spacer structure 572 can be formed separately from the outer shell 574 and attached to the outer shell 574, for example using adhesives, fasteners, etc. In some embodiments, the spacer structure 572 and the outer shell 574 are formed using direct manufacturing techniques.

[0129] Fig. 5FAn appliance 580 is shown having a compliant layer 582 attached to the inner surface of an outer shell 574. According to various embodiments, the compliant layer 582 includes a plurality of spacer structures 588. Similar to other embodiments herein, the outer shell 584 defines a tooth receiving cavity for a tooth 586. A plurality of spacer structures 588 are positioned on the compliant layer 582 and between the outer shell 584 and the tooth 586, thereby engaging the tooth 586. The compliant layer 582 and the spacer structures 588 can be solid. In some embodiments, the compliant layer 582 and the spacer structures 588 can be a single integral structure. In some embodiments, the compliant layer 582 and the spacer structures 588 can be discrete structures. In some embodiments, the spacer structures 588 and the compliant layer 582 can be hollow. In some embodiments, each spacer structure 588 engages a different portion of a tooth 586, such as a different tooth surface (e.g., buccal, lingual, or occlusal). The spacer structures 588 can be configured to transfer and distribute the forces and / or torques generated by the outer shell 584 to different portions of the teeth 586. In some embodiments, the spacer structures 588 are distributed around the compliant structures 582 so that they distribute the repositioning forces from the outer shell 584 to the teeth 586. In some embodiments, the spacer structures 588 are formed by printing or spraying on the inner surface of the outer shell 584. Alternatively, the spacer structures 588 and the compliant structures 582 can be formed separately from the outer shell 584 and attached to the outer shell 584, for example using adhesives, fasteners, etc. In some embodiments, the spacer structures 588, the compliant structures 582, and the outer shell 584 are formed using direct manufacturing techniques.

[0130] Figure 5G An appliance 590 is shown having a plurality of discrete spacer structures 592 attached to the inner surface of an outer shell 594 and the inner surface of an inner shell 591 according to various embodiments. The inner surface of the shell 591 defines a tooth receiving cavity for a tooth 596. The plurality of discrete spacer structures 592 are located between the outer shell 594 and the inner shell 591 and regulate the engagement of the inner shell 591 with the tooth 596. The spacer structures 592 distribute the repositioning force of the outer shell 594 to the inner shell 591, which transmits the force to the tooth 596. The spacer structures 592 can be solid. Alternatively, as further discussed herein, the spacer structures 592 can be hollow. The discrete spacer structures 592 can be configured to transmit the force and / or torque generated by the outer shell 574 to different portions of the inner shell 591 and the tooth 576. In some embodiments, the spacer structures 592 are formed by printing or spraying onto the surface of the inner shell 591. Alternatively, the spacer structure 592 may be formed separately from the outer shell 594 and joined to the outer shell 594 or the inner shell 591, such as using adhesives, fasteners, etc. In some embodiments, the spacer structure 592, the inner shell 591, and the outer shell 594 are formed using direct manufacturing techniques.

[0131] Figure 5H Shown with Figure 5E , the aligner 550 has a plurality of discrete spacer structures 552 attached to the inner surface of an outer shell 554, the inner surface of the outer shell 554 defining a tooth receiving cavity for a tooth 556. In addition, the aligner 550 includes a filling material 558 between the plurality of spacer structures 552. The filling material 558 can be a relatively compliant material so that it exerts very little force or torque on the teeth, for example, the elastic modulus of the filling material can be 1 / 2 or 1 / 10 of the elastic modulus of the spacer structure and / or the outer shell 554. In some embodiments, the filling material 558 is extremely soft, for example, in some embodiments, the filling material 558 can be a viscous fluid (e.g., a gel), and there is a thin and rigid outer surface or cover on the filling material located on the tooth surface. In some embodiments, the elastic modulus of the filling material can be 1 / 20 or even 1 / 100 of the elastic modulus of the spacer structure.

[0132] In some embodiments, the filler material 558 is selected based on its optical properties. For example, the refractive index of the filler material 558 can be matched to the refractive index of the spacer structure. In some embodiments, matching the refractive index includes matching the refractive index so that the spacer structure 552 is not easily observable on the patient during normal use. In some embodiments, the refractive index of the filler material 558 is within 10% of the refractive index of the spacer structure 552.

[0133] Some embodiments of the compliant internal structures described herein directly contact the tooth surface to transmit force and / or torque. In other embodiments, the compliant internal structure indirectly engages the tooth through one or more attachments mounted to the tooth surface, rather than directly contacting the tooth surface. The geometry and position of the internal structure and / or attachments can be designed to produce specific forces and / or torques when the brace is worn on the teeth. The use of attachments is beneficial for improving control of the applied forces and / or torques and causing tooth movement that would otherwise be difficult to produce using only the brace housing. The brace can include any number of internal structures that are configured to engage a corresponding number of attachments mounted on the patient's teeth.

[0134] Fig. 6AAn appliance 600 is shown that includes an internal structure 602 that engages an attachment 604 mounted on a tooth according to multiple embodiments. As described herein, the internal structure 602 can be a compliant discrete pad element attached to the inner surface of a rigid outer shell 606. When the patient wears the appliance 600, the internal structure 602 can contact the attachment 604 attached to the received tooth 608, thereby transmitting the force and / or torque generated by the outer shell 606 to the tooth 608 via the attachment 604. Optionally, the rigid outer shell 606 can include a recess 610 that is shaped to accommodate and hold the attachment 604 when engaged with the internal structure 602. In some embodiments, the stiffness of the attachment 604 is greater than the internal structure 602, so that the internal structure 602 is compressed between the outer shell 606 and the attachment 604. The internal structure 602 can present a spring-type resistance to compression to apply a force to the attachment 604, which is transmitted to the tooth 608 below the surface. This method can provide a tooth repositioning force with greater reproducibility.

[0135] Various embodiments herein provide a compliant internal structure that is attached to a rigid outer shell, but not to a tooth or an attachment. Alternatively, the internal structure can be attached to a tooth surface or an attachment attached to a tooth surface, rather than to an outer shell. In some embodiments, the internal structure mounted on the tooth can be considered a compliant attachment. The geometry and position of the compliant attachment can be designed to engage with the rigid outer shell so as to transmit forces and / or torques generated by the rigid outer shell to the teeth beneath the surface.

[0136] Figure 6B An appliance 620 including a compliant tooth-mounted attachment 622 is shown according to various embodiments. The compliant attachment 622 is mounted on the surface of a tooth 624 (the tooth 624 is housed within a cavity defined by a rigid outer shell 626 of the appliance 620). The rigid outer shell 626 may include a recess 628 that receives the compliant attachment 622. When the appliance 620 is worn on the patient's teeth, the rigid outer shell 626 may engage the attachment 622, and the attachment 622 may distribute the forces and / or torques generated by the rigid outer shell 626 to the teeth 624 beneath the surface. Using a compliant attachment 622 may provide improved control over the amount of force and / or torque applied to the teeth 624 compared to a rigid attachment.

[0137] In some embodiments, the compliant internal structure may be provided with a protective layer to reduce wear. The protective layer may be formed as a layer of material or a coating deposited on the compliant internal structure. The protective layer may have a greater stiffness and / or hardness than the internal structure so as to protect the internal structure from abrasion. In some embodiments, the protective layer is formed on one or more exposed surfaces of the compliant internal structure, such as on an exposed surface arranged to engage a relatively rigid and / or hard object. For example, for a compliant internal structure attached to an inner surface of a rigid outer shell, the protective layer may be formed on a surface of the internal structure that engages a tooth or attachment to be accommodated. As another example, for a compliant internal structure attached to a tooth or an attachment mounted on a tooth, the protective layer may be formed on a surface of the internal structure that engages the rigid outer shell. This method may be particularly beneficial for a compliant structure mounted on a tooth surface (e.g., a compliant attachment) or an attachment surface because such a structure is more likely to be subjected to grinding forces associated with jaw movements such as chewing.

[0138] In some embodiments, an anti-fouling protective layer may be formed on the surface of the calibrator. The anti-fouling protective layer may be an impermeable or semi-permeable layer that resists contamination from fluids (such as coffee and carbonated beverages), food, and other things.

[0139] In some embodiments, a biocompatible layer is provided on the exterior of the calibrator. For example, some patients may be sensitive, such as allergic, to certain materials (e.g., latex). To reduce the likelihood of an allergic reaction in a patient, the calibrator may be formed with a biocompatible layer that provides a barrier between potentially harmful substances, such as allergens, and the patient's tissue.

[0140] Some compliant structures and rigid structures may be sensitive to wear and damage caused by fluids in the oral cavity. For example, saliva may weaken the calibrator structure, increase the rate at which it wears and reduce its rigidity. Therefore, in some embodiments, a saliva-resistant layer may be formed on one or more surfaces of the calibrator structure to resist wear caused by saliva. In some embodiments, the calibrator may include a hydrophobic or hydrophilic layer or coating.

[0141] In some embodiments, multiple protective layers may be used. For example, an anti-fouling protective layer may be formed on an abrasion-resistant protective layer.

[0142] Figure 6CA compliant accessory-mounted structure 640 with a protective layer 642 is shown in accordance with various embodiments. In the depicted embodiment, the compliant structure 640 is a pad structure that is attached to a surface of an accessory 644 mounted on a tooth 646. The accessory 644 can be relatively rigid and / or hard compared to the compliant structure 640. The compliant structure 640 can be positioned to engage a rigid outer housing (not shown) housing the tooth 646 and the accessory 644. The protective layer 642 can be formed on the surface of the compliant structure 640 that will contact the rigid outer housing, thereby protecting the compliant structure 640 from wear due to abrasion of the rigid outer housing.

[0143] Orthodontic appliances can allow relatively independent application of force and / or torque on different teeth by integrating the compliant internal structure connected to the rigid outer shell. In some embodiments, this can be achieved by increasing the rigidity of the outer shell, so as to reduce the degree of deformation and / or deflection of one shell part causing deformation and / or deflection of other shell parts. In such embodiments, the rigidity of the outer shell can be significantly greater than the shell used in other types of orthodontic appliances. For example, an appliance configured for the application of independent force and / or torque can include an outer shell with an elastic modulus of about 2.5GPa or an elastic modulus in the range of about 1Gpa to about 25GPa. In some embodiments, increasing rigidity can be achieved by increasing the thickness of the outer shell. According to the method provided herein, multiple compliant internal structures can be connected to the rigid outer shell, so that force and / or torque are transmitted to multiple individual teeth or multiple tooth subgroups. Such an appliance can allow force and / or torque to be applied based on each tooth and customized, and improve the predictability of the impact on adjacent teeth.

[0144] Fig. 7A , Figure 7B and Figure 7C Schematically illustrates the independent forces applied to teeth according to various embodiments. Fig. 7A An appliance 700 is shown in which the outer housing includes a rigid tongue 702. In an alternative embodiment, the appliance 700 may include rigid cheeks instead of a rigid tongue. A plurality of compliant internal structures (schematically depicted as springs 704) are attached to the inner surface of the tongue 702, each of which is positioned to engage a single tooth 706. The tongue 702 may have sufficient rigidity so that forces and / or torques may be applied independently to each tooth 706 via the corresponding internal structures. Figure 7B An appliance 720 is shown that is similar to the appliance 700 except that the outer housing includes rigid cheek portions 722 in addition to a rigid tongue portion 724. Compliant internal structures (schematically depicted as springs 726) may be coupled to the cheek portions 722 and / or tongue portion 724 to engage a plurality of individual teeth 728 and transmit forces and / or torques. Figure 7C An appliance 740 is shown that is similar to the appliance 700, except that the outer shell is a rigid cheek portion 742, rather than a rigid tongue portion. Compliant internal structures (schematically depicted as springs 744) are attached to the inner surface of the cheek portions 742, each of which is positioned to engage a single tooth 746. The cheek portions 742 can be sufficiently rigid so that forces and / or torques can be applied independently to each tooth 746 via the corresponding structures.

[0145] In an alternative embodiment, an orthodontic appliance configured to apply independent forces and / or torques may include a plurality of discrete rigid shell segments, each rigid shell segment housing a subset of teeth, rather than Fig. 7A , Figure 7B and Figure 7C The continuous rigid shell portion depicted in FIG. These shell segments can be connected to each other via bends or other connecting elements that allow relative movement of the shell segments. The use of discrete shell segments can further isolate subsets of teeth from forces and / or torques applied to other subsets.

[0146] In some embodiments, the surface properties of the compliant internal structure can be adjusted to further improve the contact between the braces and the teeth accommodated. In some embodiments, the internal structure is formed by a viscous material or a high friction material to help generate tangential forces and / or torques on the tooth surface. Alternatively or in combination, the internal structure can have a textured surface that is shaped to control the movement of saliva relative to the tooth surface, for example, by guiding saliva away from the tooth surface or flowing to the tooth surface with a channel. For example, guiding saliva with a channel from the engagement area can allow a higher friction contact between the braces and the tooth surface. The surface texture for removing saliva can include a protruding structure, a gap or other sponge-like structure, a flexible channel that can be deformed to push the saliva out, or a combination thereof. In other embodiments, guiding saliva with a channel toward the engagement area can increase the surface tension between the braces and the teeth, which can improve the transmission of force and / or torque to the teeth. The surface texture for guiding saliva with a channel toward the engagement area can include multiple channels that are shaped to absorb and retain saliva by capillary action. Optionally, the modification of the surface properties may be accomplished by applying a coating having the desired properties to the internal structure, rather than modifying the properties of the internal structure itself.

[0147] In addition to the rigid outer shell and the compliant internal structure, the orthodontic appliance provided herein may include other components. In some embodiments, the appliance may further include one or more additional layers, which are attached to the outer surface of the outer shell, and these layers may perform various functions. For example, the appliance may include the outermost layer attached to the outer surface of the outer shell. The rigidity of the outermost layer may be less than the outer shell, so as to provide a buffer for the teeth relative to the jaw, improve the comfort of the patient, and / or help to place the appliance on the teeth. Alternatively or in combination, the rigidity and / or hardness of the outermost layer may be greater than the outer shell, for example, to protect the appliance from scratches, wear, staining, biological interactions (e.g., reducing plaque or biological growth), etc. For example, the hardness of the outermost layer may be greater than or equal to about 70 Shore D or about 90 Shore D. In some embodiments, the property of the outermost layer is selected to improve the aesthetics of the appliance. A aligner with local variations in geometry (e.g., uneven thickness, protrusions, recesses, etc.) may have a less aesthetically pleasing appearance due to uneven optical properties (e.g., reflectivity). Therefore, the outermost layer may be designed to provide a relatively smooth outer surface to improve the appearance of the aligner. The outermost layer may be thinner than the outer shell and / or the inner structure to reduce the contribution of the outermost layer to the overall properties of the aligner.

[0148] Similarly, in some embodiments, the brace may further include one or more additional layers attached to the inner surface of the outer shell and / or the inner structure, and these layers may perform a variety of different functions. For example, the brace may include an innermost layer attached to the inner surface of the inner structure, and the stiffness and / or hardness of the innermost layer may be greater than the inner structure, for example to protect the inner structure from scratches, wear, staining, biological interactions, etc. For example, the hardness of the innermost layer may be greater than or equal to about 70 Shore D or about 90 Shore D. Alternatively, the stiffness of the innermost layer may be less than that of the inner structure to provide cushioning for the teeth opposite the jaw, improve comfort, etc. The innermost layer may be thinner than the outer shell and / or the inner structure to reduce the contribution of the innermost layer to the overall properties of the brace.

[0149] The present disclosure also provides various methods for manufacturing an orthodontic appliance with different local properties described herein. As discussed herein, such an appliance can be produced by using a variety of materials (e.g., relatively rigid materials and relatively compliant materials), and different parts have different material compositions and / or geometries. In some embodiments, the appliance (or part of the appliance) herein can be produced using indirect manufacturing techniques, such as by thermoforming on a male or female mold. The indirect manufacture of an orthodontic appliance may include manufacturing a male or female mold of a patient's dentition with a target arrangement (e.g., by additive manufacturing, milling, etc.), and thermoforming one or more material sheets on the mold to produce an appliance shell. In some embodiments, the appliance is manufactured by producing a sheet of material of different parts with different local properties, and then forming (e.g., thermoforming) a sheet of material on a mold (e.g., a male mold of a tooth arrangement) to manufacture a shell. Optionally, the step of adding and / or removing additional material can occur after the shell has been formed to produce the final appliance.

[0150] In order to ensure that the forces and / or torques are accurately generated and applied to the appropriate teeth, it is important that the different appliance parts are correctly positioned relative to the underlying teeth. The positioning of the various parts of the appliance in the final appliance may depend on how the various parts are positioned on the sheet of material used to form the appliance. Therefore, it is beneficial to determine the spatial correspondence between the locations on the sheet of material, the various parts of the appliance, and the various parts of the patient's teeth to ensure accurate appliance manufacturing.

[0151] Fig. 8A The spatial correspondence between a patient's teeth 800, an orthodontic brace 802, and a sheet of material 804 is shown according to multiple embodiments. As described herein, the brace 802 may include a shell having a plurality of tooth-receiving cavities, each tooth-receiving cavity being shaped to accommodate a corresponding tooth of the patient's jaw. The brace 802 may be formed from a sheet of material 804, such as by thermoforming on a mold. Thus, each tooth may be spatially mapped to a corresponding shell portion of the brace 802, and each shell portion may be spatially mapped to a corresponding sheet portion of the sheet of material 804. For example, in the illustrated embodiment, the tooth 806 is housed in a shell portion 808 formed by a sheet portion 810. The spatial mapping relationship may then be used as a basis for manufacturing the sheet of material 804.

[0152] Figure 8B A sheet of material 820 for forming an orthotic device is shown according to various embodiments. The sheet of material 820 may include a plurality of distinct sheet portions 822, each sheet portion 822 corresponding to a respective housing portion of the orthotic device to be formed from the sheet 820. The distinct sheet portions 822 of the sheet of material 820 (e.g., Figure 8BThe sheet portions 822 (shown as different shadings in ) can have different properties (e.g., thickness, stiffness, elastic modulus, etc.) such that the formed aligner has multiple shell portions with different properties. For example, different sheet portions can have different material compositions such that one or more materials used to form each sheet portion can vary. Alternatively or in combination, different sheet portions 822 can use one or more of the same materials, but the geometry (e.g., thickness) of the one or more materials can be changed to achieve different properties. In some embodiments, the sheet portions 822 can be mapped to one or more teeth, for example, sheet portion 822a is elongated and mapped to two teeth, while sheet portion 822b is elongated and mapped to three teeth.

[0153] In some embodiments, the different properties are uniform across the sheet portion 822. In some embodiments, the different properties may be variable within the sheet portion 822 or across the sheet of material 820. For example, Figure 8C and Fig.8D Examples of variable properties on sheet 820 and separate sheet portions 822 are shown. Figure 8C A cross section through sheet 820 and sheet portions 822d and 822c is shown. Sheet portion 822d shows an example of a sheet portion having a step change at its edge and a variable convex portion from one side to the other on portion 822d. Sheet portion 822c shows an example of a sheet portion having a concave portion in which the thickness changes from one side to the other, but without a step change at its edge. The thickness profile and cross-sectional shape of sheet portion 822 and sheet of material 820 may vary depending on the desired properties of the resulting aligner.

[0154] Fig.8D Shown through sheet 820 and Figure 8B Another cross section of four sheet portions 822a, 822d, 822e, 822f. Sheet portion 822a is an example of a sheet portion 822 having a step change at its edge but a continuous thickness, while sheet portion 822d is an example of a sheet portion having a step change at its edge but a variable thickness along its length, a first thickness at one edge and a second thickness at another edge thereof. Sheet portion 822e is an example of a sheet portion having a constant thickness, while sheet portion 822f is an example of a concave variable thickness sheet portion having a continuous thickness change at the edge of the sheet portion.

[0155] Fig. 9 A method 900 for designing and manufacturing an orthodontic appliance is shown in accordance with various embodiments. In some embodiments, the method 900 is a computer-based method such that some or all of the steps in the method 900 are performed by one or more processors of a computing device or system.

[0156] In step 910, a 3D representation of a shell is received. For example, the 3D representation can be a 3D digitized model. As described herein, the shell can include a plurality of cavities shaped to accommodate the patient's teeth. In some embodiments, the shell includes a plurality of shell portions, each shell portion being positioned to accommodate and engage a different subset of the patient's teeth (e.g., a single tooth, a plurality of teeth, a portion of teeth). The 3D representation can depict the 3D geometry of the aligner shell for a treatment phase of an orthodontic treatment plan. As described herein, the 3D geometry can be generated based on a digitized representation of the patient's teeth in a desired tooth arrangement.

[0157] In step 920, a 2D representation of the sheet of material to be used to form the shell is generated. The 2D expression may correspond to a 3D representation of the shell, such that the 3D expression is used as a basis for generating the 2D expression. In some embodiments, the 3D expression is converted, for example by "planarization" or "unfolding", to generate the 2D expression. The conversion process may be based on the expected behavior of the sheet of material during the forming process. For example, the conversion method may take into account factors such as the geometry of the tooth-receiving cavity, the manufacturing method used to form the shell, the manufacturing temperature to be used, one or more materials to be used, the material properties of the materials to be used (e.g., strain rate), or a combination thereof. Alternatively or in combination, step 920 may include determining the correspondence between individual points on the 2D representation of the sheet of material and points on the 3D representation of the shell by simulating or emulating a direct deformation or inverse deformation from the 2D sheet geometry to the 3D shell geometry.

[0158] The sheet of material may include multiple sheet portions, each sheet portion corresponding to a corresponding shell portion, and the 2D expression may include information representing these spatial relationships. The spatial correspondences may be determined, for example, by tracking various points on the 3D expression during the conversion process to determine the final positions of these points in the 2D expression. Thus, each sheet portion in the 2D expression may be mapped to a corresponding shell portion in the 3D expression. Then, as further discussed herein, the 2D expression may be updated, processed and / or modified at selected locations to selectively and locally modify the properties of the 3D shell to be formed.

[0159] In step 930, a material composition is determined for the sheet of material. As further described herein, the sheet of material may be formed from a plurality of overlapping material layers, a plurality of non-overlapping material portions, or a combination thereof. In some embodiments, a material composition is determined for each of a plurality of sheet portions, and at least some of the sheet portions have different material compositions (e.g., different numbers of material layers, different combinations of material types, different material layer thicknesses, etc.). For example, some sheet portions may be manufactured using a compliant material coupled to a rigid material, while other portions may be manufactured using only a rigid material, such that the resulting orthotic device has a rigid outer shell coupled to a compliant internal structure at specific locations. Optionally, at least some of the sheet portions may have different geometries (e.g., shape, thickness, etc.).

[0160] As described herein, different shell portions of an orthotic device can be designed to have different properties in order to apply forces and / or torques to specific subsets of teeth. To achieve this, sheet portions corresponding to the shell portions can be manufactured with different properties. The material composition of each sheet portion can be determined based on the desired properties of that particular portion. For example, a desired stiffness can be determined for each sheet portion, and the material composition of each sheet portion can be determined based on the desired hardness.

[0161] In step 940, instructions for manufacturing a sheet of material are generated. These instructions can be transmitted to a manufacturing system, such as a 3D printer or a computer numerical control (CNC) milling machine. These instructions can cause the manufacturing system to manufacture a sheet of material having a plurality of sheet portions having the material composition determined in step 930. The manufacturing process may include an additive manufacturing process, a subtractive manufacturing process, or a combination thereof. For example, the sheet of material may be manufactured by milling, etching, coating, jetting, printing, bonding, spraying, extrusion, deposition, or a combination thereof. In some embodiments, the sheet of material is manufactured using a direct manufacturing technique as further discussed herein.

[0162] In step 950, instructions are generated for forming a shell from the manufactured material sheet. These instructions can be transmitted to a forming system such as a thermoforming system. In such an embodiment, the shell can be formed by thermoforming the manufactured material sheet on a mold so that multiple sheet portions of the material sheet are formed into multiple shell portions of the shell. In some embodiments, step 950 includes accurately aligning the manufactured material sheet with the mold to ensure that a shell with a desired material composition is formed at the expected location.

[0163] Method 900 can be used to produce any embodiment of the braces described herein, such as a brace having a rigid outer shell and a compliant inner structure. For example, method 900 can be used to manufacture a sheet of material having a rigid outer layer and a compliant inner layer. The sheet of material can include multiple sheet portions having different material compositions (e.g., different thicknesses of the compliant inner layer). The sheet of material can be formed into a shell so that when the shell is worn by a patient, the compliant inner layer is positioned between the rigid outer layer and the patient's teeth. The rigid outer layer can be configured to generate force and / or torque when the shell is worn, and the compliant inner layer can be configured to distribute the force and / or torque to one or more teeth contained within the shell.

[0164] Although the above steps illustrate a method 900 of design and manufacture according to a number of embodiments, one of ordinary skill in the art will recognize that many variations may be made based on the teachings described herein. Some steps may include sub-steps. Some steps may be optional, such as one or more of steps 930, 940, or 950. The order of the steps may be changed as desired. For example, in an alternative embodiment, step 950 may be performed after step 920 and before step 930.

[0165] Fig. 10A An additive manufacturing process 1000 for manufacturing an orthotic device according to multiple embodiments is shown. The process 1000 can be used in conjunction with any of the orthotic device manufacturing methods described herein (e.g., method 900). In step 1010, a sheet of material including a layer of a first material is provided. For example, the first material can be a relatively rigid material. In step 1020, a different second material is added to one or more portions of the first layer. For example, the second material can be a relatively compliant material. The second material can be applied, for example, by selective coating, spraying, printing, stereolithography, bonding, extrusion, or a combination thereof, so as to produce a desired shape profile (e.g., a single continuous layer, multiple discrete structures, variable thickness, etc.). Optionally, step 1020 can be repeated as needed to add any number of materials to the sheet of material. Optionally, the process 1000 can include joining multiple layers of the same material instead of using different materials. The number and / or thickness of the material layers can vary so as to produce desired properties. In some embodiments, steps 1010 and 1020 are performed using one or more direct manufacturing techniques described herein. In step 1030, the sheet of material is formed into a shell that is shaped to be worn on the teeth. For example, a sheet formed of a rigid first material and a compliant second material can be molded so that the first material forms an outer shell and the second material is located inside the shell.

[0166] Fig. 10BA subtractive manufacturing process 1050 for manufacturing an orthodontic appliance according to multiple embodiments is shown. Process 1050 can be used in conjunction with any of the orthodontic appliance manufacturing methods described herein (e.g., method 900). In step 1060, a sheet of material is provided that includes a first layer of a first material and a second layer of a second material. For example, the first material can be a relatively rigid material and the second material can be a relatively compliant material. In step 1070, one or more portions of the second layer are removed. These portions of the second layer can be removed, for example, by milling, chemical etching, laser etching, or a combination thereof, so as to produce a desired shape profile (e.g., a single continuous layer, multiple discrete structures, variable thickness, etc.). Optionally, step 1070 can also include removing one or more portions of the first layer. In step 1080, the sheet of material is formed into a shell that is shaped to be worn on the teeth. For example, the first layer can form an orthodontic appliance shell and the second layer can be located inside the shell.

[0167] Fig.11A and Fig. 11B 1 shows a material sheet made from a plurality of overlapping material layers 1100a-1100d according to various embodiments. Fig.11A (a cross-sectional view is shown) as shown, a plurality of overlapping material layers 1100a-1100d may be provided. Some or all of the material layers 1100a-1100d may be made of different types of materials and / or have different properties, as shown by the different shading in the described embodiments. Alternatively, some or all of the material layers 1100a-1100d may be made of the same type of material and / or have the same properties. In some embodiments, the coverage areas of some or all of the layers are different from each other. For example, in the illustrated embodiment, layer 1100a spans the entire sheet of material, while layers 1100b-1100d only partially span the sheet of material. Partially covered layers may be manufactured in a variety of ways, for example, by selectively removing one or more layer portions from a larger layer, manufacturing the layer to include only the desired portions, etc.

[0168] like Fig. 11B As shown, material layers 1100a-1100d can be joined together to form a multilayer material sheet 1102. Different layers 1100a-1100d can be joined to each other sequentially, or can all be joined together at the same time. In some embodiments, the material sheet 1102 is formed using the direct manufacturing technology described herein. The manufactured material sheet 1102 may include multiple layers of different materials, with different material compositions at different locations depending on the coverage of each individual material layer. Different parts of the material sheet 1102 may have different thicknesses based on the number and / or thickness of the layers used to form each part. In some embodiments, the material sheet may have two, three, four or more layers of similar or different materials.

[0169] FIG. 12A to FIG. 12C 1 shows a material sheet made from a plurality of non-overlapping material portions 1200a-1200c according to various embodiments. Fig. 12A As shown in (a cross-sectional view is shown), a plurality of non-overlapping material portions 1200a-1200c may be provided. Some or all of the material portions 1200a-1200c may be made of different types of materials and / or have different properties, as shown by the different shading in the illustrated embodiment. In some embodiments, the coverage areas of some or all of the portions are different from each other. For example, in the illustrated embodiment, each portion 1200a-1200c spans a different portion of the material sheet.

[0170] like Fig. 12B As shown, material portions 1200a-1200c can be joined together to form a single layer material sheet 1202. Different portions 1200a-1200c can be joined to each other in sequence, and all can be joined together at the same time. In alternative embodiments, the material sheet 1202 can be manufactured without first providing discrete material portions 1200a-1200c, for example by using a printing process or selective coating to apply different materials at different locations. In some embodiments, the material sheet 1202 is formed using the directed manufacturing technology described herein. Depending on the position of each material portion, the manufactured material sheet 1202 can include different material compositions at different sheet portions.

[0171] Optionally, one or more support layers 1204 may be attached to the single layer material sheet 1202, thereby creating a multi-layer material sheet 1206. The support layer 1204 may be used to reinforce the single layer material sheet 1202, particularly at or near the area where the different material portions 1200a-1200c are joined together. In some embodiments, a single support layer 1204 is used. Alternatively, multiple support layers may be used, such as multiple support layers attached to the upper and lower surfaces of the single layer material sheet 1202 to surround the sheet 1202. The support layers may be relatively thin compared to the single layer material sheet 1202 so as to have little or no effect on the stiffness of the final sheet 1206. This approach may be used to provide a stronger sheet and reduce the likelihood of breakage or separation between the different material portions 1200a-1200c.

[0172] The various embodiments of the orthodontic appliances presented herein can be manufactured in a variety of ways. In some embodiments, the orthodontic appliances (or portions thereof) herein are produced using direct manufacturing techniques such as additive manufacturing techniques (also referred to herein as "3D printing") or subtractive manufacturing techniques (e.g., milling). In some embodiments, direct manufacturing involves forming an object (e.g., an orthodontic appliance or a portion thereof) without using a physical template (e.g., a mold, a mask, etc.) to define a target geometry. Additive manufacturing techniques can be categorized as follows: (1) slot stereolithography (e.g., stereolithography), in which an object is built layer by layer from a slot of liquid photopolymer resin; (2) material jetting, in which material is jetted onto a build platform using a continuous or drop-on-demand (DOD) process; (3) binder jetting, in which alternating layers of build material (e.g., powder-based material) and binding material (e.g., liquid binder) are deposited by a print head; (4) fused deposition modeling (FDM), in which material is drawn through a nozzle, heated, and deposited layer by layer; (5) powder bed fusion, which includes but is not limited to direct metal laser sintering (DMLS), electron beam melting (EBM), selective heat sintering (SHS), selective laser melting (SLM), and selective laser sintering (SLS); (6) sheet lamination, which includes but is not limited to layered object manufacturing (LOM) and ultrasonic additive manufacturing (UAM); and (7) directed energy deposition, which includes but is not limited to laser engineered grid forming, directed light manufacturing, direct metal deposition, and 3D laser cladding. For example, stereolithography can be used to directly manufacture one or more correctors herein. In some embodiments, stereolithography includes selectively polymerizing a photosensitive resin (e.g., a photopolymer) using light (e.g., ultraviolet light) according to a desired cross-sectional shape. The geometry of the object can be built layer by layer by sequentially polymerizing multiple object cross sections. As another example, the corrector herein can be directly manufactured using selective laser sintering. In some embodiments, selective laser sintering includes using a laser beam to selectively melt and fuse layers of powdered material according to a desired cross-sectional shape to construct a target geometry. As another example, the corrector herein can be directly manufactured by fused deposition molding. In some embodiments, fused deposition molding includes melting and selectively depositing filaments of thermoplastic polymers in a layer-by-layer manner to form an object. In yet another example, material jetting can be used to directly manufacture the corrector herein. In some embodiments, material jetting includes jetting or extruding one or more materials onto a build surface to form a continuous layer of a target geometry.

[0173] In some embodiments, the direct manufacturing method provided herein builds the target geometry in a layer-by-layer manner, and the continuous layers are formed in discrete building steps. Alternatively or in combination, a direct manufacturing method that allows the continuous construction of the target geometry can be used, which is referred to as "continuous direct manufacturing" in this article. Various types of continuous direct manufacturing methods can be used. As an example, in some embodiments, the corrector herein is manufactured using "continuous liquid interphase printing", in which the object is continuously built from a reservoir of photopolymerizable resin by forming a gradient of partially cured resin between the building surface of the object and the "dead zone" where polymerization is prohibited. In some embodiments, a semipermeable membrane is used to control the transfer of a photopolymerization inhibitor (e.g., oxygen) into the dead zone to form a polymer gradient. The manufacturing speed that can be achieved by continuous liquid interphase printing is about 25 times to about 100 times faster than other direct manufacturing methods, and about 1000 times faster speeds can be achieved by incorporating a cooling system. Continuous liquid interphase printing is described in U.S. Patent Publication Nos. 2015 / 0097315, 2015 / 0097316, and 2015 / 0102532, the disclosure of each of which is incorporated herein by reference in its entirety.

[0174] As another example, a continuous direct manufacturing method can achieve continuous construction of a target geometry by continuously moving the build platform (e.g., in the vertical or Z direction) during the irradiation phase, so that the hardening depth of the irradiated photosensitive polymer is controlled by the movement speed. Thus, continuous polymerization of the material on the build surface can be achieved. This method is described in U.S. Pat. No. 7,892,474, the disclosure of which is incorporated herein by reference in its entirety.

[0175] In another example, a continuous direct manufacturing method may involve extruding a composite material consisting of a curable liquid material around a solid thread. The composite material may be extruded along a continuous three-dimensional path to form an object. This method is described in U.S. Patent Publication No. 2014 / 0061974, the disclosure of which is incorporated herein by reference in its entirety.

[0176] In yet another example, a continuous direct manufacturing method utilizes a "heliolithography" method, in which a liquid photopolymer is cured under focused radiation while the build platform is continuously rotated and raised. Accordingly, a target geometry can be continuously built along a spiral build path. Such a method is described in U.S. Patent Publication No. 2014 / 0265034, the disclosure of which is incorporated herein by reference in its entirety.

[0177] In some embodiments, the orthodontic appliances of the present invention are formed using direct manufacturing and indirect manufacturing techniques. For example, a first portion of the appliance may be formed using a direct manufacturing technique (e.g., slot light curing, material jetting, adhesive jetting, material extrusion, powder bed fusion, sheet lamination, or directed energy deposition), and an indirect manufacturing technique (e.g., thermoforming) may be used to form a second portion of the appliance. In some embodiments, direct manufacturing techniques are used to manufacture a sheet of material having variable material properties and / or composition as described herein, and indirect manufacturing techniques are used to form the sheet of material into the appliance.

[0178] The direct manufacturing method provided herein is compatible with a variety of materials, including but not limited to one or more of the following: polyester, copolyester, polycarbonate, thermoplastic polyurethane, polypropylene, polyethylene, polypropylene and polyethylene copolymer, acrylic acid, cyclic block copolymer, polyetheretherketone, polyamide, polyethylene terephthalate, polybutylene terephthalate, polyetherimide, polyethersulfone, polytrimethylene terephthalate, styrene block copolymer (SBC), silicone rubber, elastomer alloy, thermoplastic elastomer (TPE), thermoplastic vulcanizate (TPV) elastomer, polyurethane elastomer, block copolymer elastomer, polyolefin blended elastomer, thermoplastic copolyester elastomer, thermoplastic polyamide elastomer or its combination. The material for direct manufacturing can be provided in uncured form (e.g., as liquid, resin, powder, etc.) and can be cured (e.g., by photopolymerization, photocuring, gas curing, laser curing, crosslinking, etc.) to form an orthodontic appliance or a part thereof. The properties of the material before curing may be different from the properties of the material after curing. Once cured, the materials herein can exhibit sufficient strength, stiffness, durability, biocompatibility, etc. for use in orthodontic appliances. The post-curing properties of the materials used can be selected based on the desired properties of the corresponding part of the appliance.

[0179] In some embodiments, relatively rigid portions of an orthodontic appliance may be formed by direct manufacturing using one or more of the following materials: polyesters, copolyesters, polycarbonates, thermoplastic polyurethanes, polypropylene, polyethylene, copolymers of polypropylene and polyethylene, acrylics, cyclic block copolymers, polyetheretherketones, polyamides, polyethylene terephthalate, polybutylene terephthalate, polyetherimides, polyethersulfones, and / or polytrimethylene terephthalate.

[0180] In some embodiments, the relatively elastic portion of the orthodontic brace can be formed by direct manufacturing using one or more of the following materials: styrene block copolymers (SBC), silicone rubber, elastomeric alloys, thermoplastic elastomers (TPE), thermoplastic vulcanizate (TPV) elastomers, polyurethane elastomers, block copolymer elastomers, polyolefin blend elastomers, thermoplastic copolyester elastomers and / or thermoplastic polyamide elastomers.

[0181] Optionally, the direct manufacturing methods described herein allow for the manufacture of aligners comprising multiple materials, referred to herein as "multi-material direct manufacturing". In some embodiments, the multi-material direct manufacturing method includes forming an object from multiple materials simultaneously in a single manufacturing step. For example, a multi-end extrusion device can be used to selectively dispense multiple types of materials (e.g., resins, liquids, solids, or combinations thereof) from different material supply sources so as to manufacture an object from multiple different materials. Such a method is described in U.S. Patent No. 6,749,414, the disclosure of which is incorporated herein by reference in its entirety. Alternatively or in combination, the multi-material direct manufacturing method may include forming an object from multiple materials in multiple continuous manufacturing steps. For example, a first portion of an object may be formed from a first material according to any direct manufacturing method herein, and then a second portion of the object may be formed from a second material according to the method herein, and so on, until the entire object is formed. The relative arrangement of the first portion and the second portion may be changed as desired, for example, the first portion may be partially or completely sealed by the second portion of the object.

[0182] Direct manufacturing can provide various advantages compared to other manufacturing methods. For example, in contrast to indirect manufacturing, direct manufacturing allows the production of orthodontic braces without the use of any molds or templates to shape the braces, thereby reducing the number of manufacturing steps involved and improving the resolution and accuracy of the final brace geometry. In addition, direct manufacturing allows precise control of the three-dimensional geometry of the brace, such as the brace thickness. Complex structures and / or auxiliary components can be integrally formed as a single piece with the brace shell in a single manufacturing step, rather than being added to the shell in a separate manufacturing step. In some embodiments, direct manufacturing is used to produce a variety of brace geometries that are difficult to produce using alternative manufacturing techniques, such as braces with very small or fine features, complex geometries, undercuts, interproximal structures, shells with variable thickness, and / or internal structures (e.g., for improving strength and reducing weight and material usage). For example, in some embodiments, the direct manufacturing methods herein allow for the manufacture of orthodontic appliances having feature sizes less than or equal to about 5 μm, or in a range from about 5 μm to about 50 μm, or in a range from about 20 μm to about 50 μm.

[0183] Direct manufacturing can provide improved control over the geometry and material properties of the braces in three dimensions. In some embodiments, the direct manufacturing techniques described herein can be used to produce braces with substantially isotropic material properties, such as substantially the same or similar strengths in all directions. In some embodiments, the direct manufacturing techniques described herein can be used to produce braces with anisotropic material properties. For example, the material layers forming the braces may include material layers with different directionality. For example, a first layer may include a polymer material having polymer chains arranged in a substantially first direction, and a second layer may include a polymer material having polymer chains arranged in a substantially second direction, the first direction being different from the second direction. In some embodiments, the direct manufacturing method herein allows the production of orthodontic braces with strength variations along all directions not exceeding about 25%, about 20%, about 15%, about 10%, about 5%, about 1%, or about 0.5%. Alternatively, as discussed herein, direct manufacturing can be used to make orthotics with anisotropic and / or inhomogeneous material properties, such as orthotics with rigid portions (e.g., a rigid outer shell) and compliant portions (e.g., a compliant inner structure). For example, orthotics with structures as proposed herein, such as multilayers (see, e.g., FIG. 4A to FIG. 4C ), multiple discrete pad structures (see e.g. Figure 5A ), multiple discrete plug structures (see e.g. Figure 5B ), multiple discrete expandable structures (see e.g. Figure 5C ), attachment and engagement structures (see e.g. Fig. 6A ), attachments mounted on the teeth (see e.g. Figure 6B ), accessory-mounted structures (see e.g. Figure 6C ) and / or attachment templates (see e.g. Fig.17A and Fig. 17B ).

[0184] In some embodiments, the braces of the present disclosure are produced by depositing different types of materials at locations where different properties are desired using multi-material direct manufacturing. For example, a relatively rigid or hard material can be deposited at locations where increased rigidity is desired (e.g., a rigid outer shell), and a relatively compliant or elastic material can be deposited at locations where increased compliance is desired (e.g., a compliant internal structure). As discussed above and herein, manufacturing a brace from multiple materials can be performed simultaneously in a single manufacturing step, or in multiple sequential steps. In some embodiments, the compliant internal structure is formed simultaneously and integrally with the rigid outer shell, rather than being attached to the shell in a separate step after the shell has been manufactured.

[0185] Alternatively or in combination, the braces herein are produced by using direct manufacturing techniques that vary the geometry of the brace at locations where different properties are desired. For example, the direct manufacturing process can selectively vary the thickness of the material formed so as to control the composite stiffness of the brace, such as making the stiffer portion of the brace have an increased thickness compared to the more compliant portion of the brace. As another example, stiffness adjustment structures such as holes, slits, perforations, etchings, etc. can be selectively formed at certain locations in the brace so as to reduce the local stiffness at those locations. Direct manufacturing allows the formation of such structures to occur simultaneously with the formation of the brace, thereby eliminating the need for separate cutting or etching steps. In yet another example, direct manufacturing process parameters such as curing parameters (e.g., curing time, energy, power, interval, depth) can be selectively varied to affect the stiffness and / or other properties of the material. In many embodiments, control of the curing parameters is used to control the degree of crosslinking of the formed material, which in turn contributes to local stiffness (e.g., increased crosslinking produces increased stiffness, and reduced crosslinking produces reduced stiffness).

[0186] In addition, compared with other manufacturing techniques, the direct manufacturing method herein can be used to produce orthodontic braces at a faster speed. In some embodiments, the direct manufacturing method herein allows the production of orthodontic braces in a time interval of less than or equal to about 1 hour, about 30 minutes, about 25 minutes, about 20 minutes, about 15 minutes, about 10 minutes, about 5 minutes, about 4 minutes, about 3 minutes, about 2 minutes, about 1 minute, or about 30 seconds. This manufacturing speed allows, for example, to quickly produce customized braces "at the side of the treatment chair" during a regular appointment or examination.

[0187] In some embodiments, the direct manufacturing methods described herein may implement process control over various machine parameters of the direct manufacturing system or apparatus to ensure that the resulting aligner is manufactured with high precision. Such precision is beneficial in ensuring that the desired force system is accurately delivered to the teeth to effectively cause tooth movement. Process control may be implemented to take into account process variability (process variability is caused by a variety of sources such as material properties, machine parameters, environmental variables, and / or post-processing parameters).

[0188] Material properties can vary according to the properties of raw materials, the purity of raw materials, and / or process variables during raw material mixing. In many embodiments, the resin or other materials used for direct manufacturing should be manufactured under strict process control to ensure very little variability in optical properties, material properties (such as viscosity, surface tension), physical properties (such as modulus, strength, elongation), and / or thermal properties (such as, glass transition temperature, heat distortion temperature). The process control of material manufacturing process can be achieved by screening raw materials for physical properties and / or temperature, humidity and / or other process parameters during the mixing process. By implementing process control to material manufacturing process, the variability of the reduction of process parameters and the more uniform material properties of each batch of materials can be achieved. As further discussed herein, the remaining variability in material properties can be compensated by process control on the machine.

[0189] The machine parameters may include curing parameters. For curing systems based on digital light processing (DLP), the curing parameters may include power, curing time, and / or grayscale of the complete image. For laser-based curing systems, the curing parameters may include power, speed, beam size, beam shape, and / or power distribution of the beam. For printing systems, the curing parameters may include material drop size, viscosity, and / or curing power. These machine parameters may be regularly monitored and adjusted (e.g., some parameters at every 1-x layer and some parameters after each build) as part of process control on the manufacturing machine. Process control may be achieved by including sensors on the machine that measure power and other beam parameters at each layer or every few seconds and automatically adjust them through a feedback loop. For DLP machines, depending on the stability of the system, the grayscale may be measured and calibrated before, during, and / or at the end of each build, and / or at predetermined time intervals (e.g., every nth build, once an hour, once a day, once a week, etc.). Additionally, material properties and / or optical properties can be provided to the fabricator, and the machine process control module can use these parameters to adjust machine parameters (e.g., power, time, grayscale, etc.) to compensate for the variability in material properties. By implementing process control on the fabricator, the variability in the accuracy of the aligner and residual stress can be reduced.

[0190] In many embodiments, environmental variables (e.g., temperature, humidity, sunlight, or exposure to other energy / curing sources) are maintained within strict ranges to reduce variability in thickness, and / or other properties of the aligner. Optionally, machine parameters can be adjusted to compensate for environmental variables.

[0191] In many embodiments, post-processing of the brace includes cleaning, post-curing, and / or support removal processes. Relevant post-processing parameters may include the purity of the cleaning agent, cleaning pressure and / or temperature, cleaning time, post-curing energy and / or time, and / or stability of the support removal process. These parameters can be measured and adjusted as part of the process control scheme. In addition, the physical properties of the brace can be changed by modifying the post-processing parameters. Adjusting the post-processing machine parameters can provide another way to compensate for the variability of material properties and / or machine properties.

[0192] The configuration of the orthodontic appliances herein can be determined based on a treatment plan for the patient, such as a treatment plan involving sequential administration of multiple appliances for incrementally repositioning teeth. Computer-based treatment planning and / or appliance manufacturing methods can be used to assist in the design and manufacture of the appliances. For example, one or more appliance components described herein can be digitally designed and manufactured with the aid of a computer-controlled manufacturing apparatus (e.g., computer numerical control (CNC) milling, computer-controlled incremental manufacturing such as direct injection, etc.). The computer-based methods proposed herein can improve the accuracy, flexibility, and convenience of appliance manufacturing.

[0193] Fig.15 A method 1500 for designing an orthodontic appliance to be produced by direct manufacturing according to multiple embodiments is shown. The method 1500 can be applied to any embodiment of the orthodontic appliance described herein. Some or all of the steps of the method 1500 can be performed by any suitable data processing system or device (e.g., one or more processors configured with suitable instructions).

[0194] In step 1510, a movement path for moving one or more teeth from an initial arrangement to a target arrangement is determined. The initial arrangement can be determined based on a mold or scan of the patient's teeth or oral tissue (e.g., using wax bites, direct contact scanning, x-ray imaging, tomography, ultrasound imaging, and other techniques for obtaining information about the position and structure of teeth, jaws, gums, and other orthodontically related tissues). From the obtained data, a digital data set can be obtained that represents the initial (e.g., pre-processing) arrangement of the patient's teeth and other tissues. Optionally, the initial digital data set is processed to separate multiple tissue constituents from each other. For example, a data structure that digitally represents a single crown can be generated. Advantageously, a digital model of the entire tooth can be generated, including measured or inferred hidden surface and root structures, as well as surrounding bone and soft tissue.

[0195] The target arrangement of teeth (e.g., the desired and expected end result of orthodontic treatment) may be obtained from the clinician in the form of a prescription, may be calculated from basic orthodontic principles, and / or may be computationally inferred from the clinical prescription. With the description of the desired final position of the teeth and the digital representation of the teeth themselves, the final position and surface geometry of each tooth may be specified to form a complete model of the dental arrangement at the desired end of treatment.

[0196] Each tooth has both an initial position and a target position, and a movement path can be defined for the movement of each tooth. In some embodiments, the movement path is configured to move the tooth in the fastest manner with the least amount of back and forth to bring the tooth from its initial position to its desired target position. The tooth path can optionally be segmented, and the segments can be calculated so that the movement of each tooth within the segment remains within threshold limits of linear and rotational translation. In this way, the endpoints of each path segment can constitute a clinically feasible repositioning, and the collection of segment endpoints can constitute a clinically feasible sequence of tooth positions, so that moving from one point to the next in the sequence does not result in collisions at the teeth.

[0197] In step 1520, a force system is determined for producing movement of one or more teeth along a motion path. The force system may include one or more forces and / or one or more torques. Different force systems may cause different types of tooth movement, such as tilting, translation, rotation, extrusion, intrusion, root movement, etc. Biomechanical principles, modeling techniques, force calculation / measurement techniques, etc., including common knowledge and methods used in orthodontics, may be used to determine an appropriate force system to be applied to the teeth to achieve tooth movement. When determining the force system to be applied, resources that may be considered include literature, force systems determined by experiments or virtual modeling, computer-based modeling, clinical experience, minimizing unnecessary forces, etc.

[0198] In step 1530, the orthodontic device geometry for an orthodontic device configured to generate a force-adding system is determined. As described herein, the device may include a rigid outer shell and a compliant internal structure. According to various embodiments presented herein, step 1530 may include determining the shape and arrangement of the outer shell and the internal structure that will generate the force and / or torque applied to the teeth. For example, a compliant internal structure such as a discrete pad or plug may be positioned to selectively engage the teeth at a position where the force and / or torque will be applied. The determination of the orthodontic device geometry may include determining the geometry of one or more force-modifying structures formed in the internal structure and / or the outer shell so as to apply force and / or torque at a specific contact point on the tooth. Optionally, as described herein, step 1530 also includes determining the material composition for the outer shell and / or the internal structure so as to apply a desired force-adding system with reduced sensitivity to manufacturing variations. In some embodiments, the material composition is selected based on the desired properties (e.g., stiffness) of the shell and / or the internal structure.

[0199] Determination of the geometry, material composition and / or properties of the aligner can be performed using a treatment or force application simulation environment. The simulation environment can include, for example, a computer modeling system, a biomechanical system or device, etc. Optionally, a digital model of the aligner and / or teeth, such as a finite element model, can be generated. The finite element model can be created using computer program application software available from a variety of vendors. To create a solid geometric model, a computer-aided engineering (CAE) or computer-aided design (CAD) program can be used, such as the Autodesk® sold by Autodesk, Inc. of San Rafael, California. Software. To create finite element models and analyze them, program products from a number of vendors may be used, including the finite element analysis software package from ANSYS, Inc. of Canonsburg, Pennsylvania, and the SIMULIA (Abaqus) software product from Dassault Systèmes, Inc. of Waltham, Massachusetts.

[0200] Optionally, one or more appliance geometries may be selected for testing or force modeling. As described above, desired tooth movement and the force system required or desired to cause the desired tooth movement may be identified. Using the simulation environment, the candidate appliance geometries may be analyzed or modeled to determine the actual force system resulting from use of the candidate appliance. One or more modifications may optionally be made to the candidate appliance, and the force modeling may be further analyzed as described, for example, to repeatedly confirm that the appliance design produces the desired force system.

[0201] In step 1540, instructions for manufacturing an orthodontic appliance having an appliance geometry are generated. These instructions may be configured to control a manufacturing system or device to produce an orthodontic appliance having a specific appliance geometry. In some embodiments, the instructions are configured to manufacture an orthodontic appliance using direct manufacturing (e.g., stereolithography, selective laser sintering, fused deposition modeling, direct jetting, continuous direct manufacturing, multi-material direct manufacturing, etc.) according to various methods presented herein. In alternative embodiments, the instructions may be configured to indirectly manufacture the appliance, for example, by thermoforming.

[0202] Although the above steps illustrate a method 1500 for designing an orthodontic appliance according to some embodiments, one of ordinary skill in the art will recognize some variations based on the teachings described herein. Some steps may include multiple sub-steps. Some steps may be repeated as often as needed. One or more steps of method 1500 may be performed with any suitable manufacturing system or device, such as the embodiments described herein. Some steps may be optional, and the order of the steps may be changed as needed.

[0203] Fig.13 A method 1300 for digitally planning orthodontic treatment and / or design or manufacture of an appliance according to many embodiments is shown. The method 1300 can be applied to any treatment process described herein and can be performed by any suitable data processing system. Any embodiment of the appliance described herein can be designed or manufactured using the method 1300.

[0204] In step 1310, a digitized representation of the patient's teeth is received. The digitized representation may include surface topography data of the patient's oral cavity (including teeth, gum tissue, etc.). The surface topography data may be generated by directly scanning the oral cavity, a physical model (convex or concave) of the oral cavity, or an impression of the oral cavity using a suitable scanning device (e.g., a handheld scanner, a desktop scanner, etc.).

[0205] In step 1320, based on the digital representation of the teeth, one or more treatment stages are generated. A treatment stage can be an incremental repositioning stage of an orthodontic treatment process designed to move one or more of a patient's teeth from an initial tooth arrangement to a target arrangement. For example, a treatment stage can be generated by determining an initial tooth arrangement indicated by the digital representation, determining a target tooth arrangement, and determining a movement path of one or more teeth in the initial arrangement required to achieve the target tooth arrangement. The movement path can be optimized based on minimizing the total distance moved, preventing collisions between teeth, avoiding tooth movements that are more difficult to achieve, or any other suitable criteria.

[0206] In step 1330, at least one orthodontic appliance is manufactured based on the generated treatment stage. For example, a set of appliances may be manufactured to be worn sequentially by a patient to incrementally reposition the teeth from an initial arrangement to a target arrangement. Some appliances may be shaped to accommodate a tooth arrangement specified by one of the treatment stages. Alternatively or in combination, some appliances may be shaped to accommodate a tooth arrangement that is different from the target arrangement for the corresponding treatment stage. For example, as previously described, an appliance may have a geometry corresponding to an overcorrected tooth arrangement. Such an appliance may be used to ensure that an appropriate amount of force is exerted on the teeth as the teeth approach or reach a target position desired for the treatment stage. As another example, an appliance may be designed so as to apply a specified force system to the teeth and may not have a geometry corresponding to any current or planned arrangement of the patient's teeth.

[0207] In some cases, various stages of alignment or treatment phases may not be required for the design and / or manufacture of the aligner. Fig.13 As shown by the dotted lines in , the design and / or manufacture of orthodontic appliances and possible specific orthodontic treatments may include using a representation of a patient's teeth (e.g., receiving a digitized representation of the patient's teeth 1310), and then designing and / or manufacturing an orthodontic appliance based on the representation of the patient's teeth in the arrangement represented by the received representation.

[0208] Fig.14 14 is a simplified block diagram of a data processing system 1400 that can be used to perform the methods and processes described herein. The data processing system 1400 typically includes at least one processor 1402 that communicates with one or more peripheral devices via a bus subsystem 1404. These peripheral devices typically include a storage subsystem 1406 (a memory subsystem 1408 and a file storage subsystem 1414), a set of user interface input and output devices 1418, and an interface to an external network 1416. The interface is schematically shown as a "network interface" module 1416 and is connected to corresponding interface devices in other data processing systems via a communication network interface 1424. The data processing system 1400 may include, for example, one or more computers, such as personal computers, workstations, mainframes, laptops, etc.

[0209] The user interface input device 1418 is not limited to any particular device, and may generally include, for example, a keyboard, a pointing device, a mouse, a scanner, an interactive display, a touch pad, a joystick, etc. Similarly, a variety of user interface output devices may be used in the system of the present invention, and may include, for example, one or more of a printer, a display (e.g., visual, non-visual) system / subsystem, a controller, a projection device, an audio output, etc.

[0210] The storage subsystem 1406 holds the basic required programming, including computer readable media with instructions (e.g., operating instructions, etc.) and data structures. The programming modules discussed herein are typically stored in the storage subsystem 1406. The storage subsystem 1406 typically includes a memory subsystem 1408 and a file storage subsystem 1414. The memory subsystem 1408 typically includes a plurality of memories (e.g., RAM 1410, ROM 1412, etc.), including computer readable memories for storing fixed instructions, instructions and data during program execution, basic input / output systems, etc. The file storage subsystem 1414 provides persistent (non-volatile) storage for program and data files, and may include one or more removable or fixed drives or media, hard disks, floppy disks, CD-ROMs, DVDs, optical drives, etc. One or more storage systems, drives, etc. may be located at a remote location, such as by a server on a network or connected via the Internet / World Wide Web. In such a context, the term "bus subsystem" is generally used to include any mechanism for enabling the various components and subsystems to communicate with each other as intended, and may include various suitable components / systems that will be known or deemed suitable for use. It should be recognized that the various components of the system may, but need not, be in the same physical location, but may be connected via various local or wide area network media, transmission systems, etc.

[0211] Scanner 1420 includes any device for obtaining a digital representation (e.g., image, surface topography data, etc.) of a patient's teeth (e.g., by scanning a physical model of the teeth such as a cast 1421, by scanning an impression taken of the teeth, or by directly scanning the intraoral cavity), which may be obtained from the patient or a treating professional (e.g., an orthodontist), and includes a device for providing the digital representation to data processing system 1400 for further processing. Scanner 1420 may be located at a remote location relative to the other components of the system, and may transmit image data and / or information to data processing system 1400, for example, via network interface 1424. Manufacturing system 1422 manufactures aligners 1423 based on the treatment plan (including data set information received from data processing system 1400). Manufacturing machine 1422 may be located at a remote location, for example, and receive data set information from data processing system 1400 via network interface 1424.

[0212] Fig.16 A method 1600 for designing an orthodontic appliance to be produced by direct manufacturing according to multiple embodiments is shown. The method 1600 can be applied to any embodiment of the orthodontic appliance described herein. Some or all of the steps of the method 1600 can be performed by any suitable data processing system or device, for example, one or more processors configured with suitable instructions.

[0213] In step 1610, a movement path is determined for moving one or more teeth from an initial arrangement to a target arrangement. The initial arrangement can be determined based on a mold or scan of the patient's teeth or oral tissue (e.g., using wax bites, direct contact scanning, x-ray imaging, tomography, ultrasonic imaging, and other techniques for obtaining information about the position and structure of teeth, jaws, gums, and other orthodontic-related tissues). From the obtained data, a digital data set can be obtained that represents the initial (e.g., pre-processing) arrangement of the patient's teeth and other tissues. Optionally, the initial digital data set is processed to segment tissue components from each other. For example, a data structure that digitally expresses a single crown can be generated. Advantageously, a digital model of the entire tooth can be generated, including measured or inferred hidden surface and root structures, as well as surrounding bone and soft tissue.

[0214] The target arrangement of teeth (e.g., the desired and expected end result of orthodontic treatment) may be obtained from the clinician in the form of a prescription, may be calculated from basic orthodontic principles, and / or may be computationally extrapolated from the clinical prescription. With a description of the desired final position of the teeth and a digital representation of the teeth themselves, the final position and surface geometry of each tooth may be specified to form a complete model of the dental arrangement at the desired end of treatment.

[0215] Each tooth has both an initial position and a target position, and a movement path can be defined for the movement of each tooth. In some embodiments, the movement path is configured to move the tooth in the fastest manner with the least amount of back and forth to bring the tooth from its initial position to its desired target position. The tooth path can be optionally segmented, and each segment can be calculated so that the movement of each tooth within a segment remains within threshold limits of linear and rotational translation. In this way, the endpoints of each path segment can constitute a clinically feasible repositioning, and the collection of segment endpoints can constitute a clinically feasible sequence of tooth positions such that moving from one point to the next in the sequence does not result in collisions at the teeth.

[0216] In step 1620, a force system is determined for producing movement of one or more teeth along a motion path. The force system may include one or more forces and / or one or more torques. Different force systems may cause different types of tooth movement, such as tilting, translation, rotation, extrusion, intrusion, root movement, etc. Biomechanical principles, modeling techniques, force calculation / measurement techniques, etc., including common knowledge and methods used in orthodontics, can be used to determine the appropriate force system to be applied to the teeth to achieve tooth movement. When determining the force system to be applied, resources that may be considered include literature, force systems determined by experiments or virtual modeling, computer-based modeling, clinical experience, minimizing unnecessary forces, etc.

[0217] In step 1630, an accessory template design is determined for an orthodontic appliance configured to generate a force application system. The attachment template design, appliance geometry, material composition and / or properties may be determined using a treatment or force application simulation environment. The simulation environment may include, for example, a computer modeling system, a biomechanical system or device, etc. Optionally, a digital model of the appliance and / or teeth may be produced, such as a finite element model. The finite element model may be created using computer program application software available from a variety of vendors. To create a solid geometric model, a computer-aided engineering (CAE) or computer-aided design (CAD) program may be used, such as the one sold by Autodesk, Inc. of San Rafael, California. Software. To create finite element models and analyze them, program products from a number of vendors may be used, including the finite element analysis software package from ANSYS, Inc. of Canonsburg, Pennsylvania, and the SIMULIA (Abaqus) software product from Dassault Systèmes, Inc. of Waltham, Massachusetts.

[0218] Optionally, one or more attachment template designs may be selected for testing or force modeling. As described above, desired tooth movement and the force system required or desired to cause the desired tooth movement may be identified. Using the simulation environment, candidate attachment template designs may be analyzed or modeled to determine the actual force system that would result from use of the candidate appliance. One or more modifications may optionally be made to the candidate appliance, and the force modeling may be further analyzed as described, for example, to repeatedly confirm that the appliance design produces the desired force system.

[0219] In step 1640, instructions for manufacturing an orthodontic appliance including an attachment template design are generated. These instructions can be configured to control a manufacturing system or device to produce an orthodontic appliance having a specific attachment template design. In some embodiments, the instructions are configured to manufacture an orthodontic appliance using direct manufacturing (e.g., slot light curing, material jetting, adhesive jetting, material extrusion, powder bed fusion, sheet lamination, or directed energy deposition, etc.) according to various methods presented herein. In alternative embodiments, the instructions can be configured to indirectly manufacture the appliance, such as by thermoforming.

[0220] Although the above steps illustrate a method 1600 for designing an orthodontic appliance according to some embodiments, one of ordinary skill in the art will recognize some variations based on the teachings described herein. Some steps may include sub-steps. Some steps may be repeated as often as desired. One or more steps of method 1600 may be performed with any suitable manufacturing system or device, such as the embodiments described herein. Some steps may be optional, and the order of the steps may be changed as desired.

[0221] Fig.17A A directly manufactured attachment template 1700 is shown, which includes an attachment, an alignment structure, and a support for holding the attachment. The template 1700 may include an aligner 1701. The aligner 1701 includes a support 1703 to support the attachment with sufficient force to hold the attachment. The aligner 1701 is configured to accommodate the teeth and thereby align the attachment on the teeth. The attachment 1702 is designed to be attached to the patient's teeth and has a surface that is shaped to allow tooth movement forces to be applied when contacting the surface of the orthodontic appliance. The attachment 1702 is held by the support 1703. The support 1703 may define a receptacle having a shape corresponding to the attachment. The support 1703 is configured to hold the attachment so that when the attachment template is worn by the patient, the attachment contacts the teeth. The attachment is connected to the aligner 1701 by a connecting structure 1704, which is configured to hold the attachment 1702 in the support 1703 until the attachment is attached to the patient's teeth. As described in further detail below, the attachment 1702 may be broken after it has been bonded to the patient's teeth. Alternatively, the attachment may be weakly connected to the aligner, for example with a structure such as a perforation to facilitate removal of the attachment from the aligner.

[0222] In order to adhere to the patient's tooth, the attachment may include an adhesive layer 1705 deposited directly on its surface. In some embodiments, the attachment template may not include the adhesive layer 1705. In some embodiments, the surface of the patient's tooth may be prepared before the attachment is attached to the tooth, for example, the surface of the tooth may be acid etched. The adhesive layer 1705 may be directly manufactured with the rest of the attachment template. Useful choices of materials for manufacturing the adhesive layer 1705 may include one or more materials as described herein. For example, the adhesive may be an ultraviolet (UV) curable adhesive or a pressure sensitive adhesive. In some embodiments, the adhesive is omitted.

[0223] After the adhesive layer contacts the tooth, it can be induced to form a bond between the tooth and the attachment 1702 using a method appropriate to the selected material, which may, for example, include steps such as photopolymerization, application of pressure, application of heat, or chemical reaction of the adhesive material with an activator. When dealing with adhesive materials that will be used for photopolymerization, it is desirable to make the aligner 1701, attachment 1702, and / or other portions of the attachment template 1700 from a transparent material to allow the applied light to more effectively set the adhesive. Alternatively or additionally, in some cases, the adhesive layer 1705 may be applied separately or by the dentist, for example, as a separate step of manufacturing.

[0224] In some cases, the accessory template may further include a cover 1706 over the adhesive layer 1705 to protect the adhesive layer 1705 and the accessory 1702. In some cases, the cover 1706 can seal the adhesive layer and the accessory 1702 within the support 1703 before the support is attached to the patient's teeth. During the attachment process, the cover can be removed, for example, by pulling the handle 1707 to expose the accessory and adhesive, which can then be contacted with the patient's teeth by placing the accessory template on the patient's teeth.

[0225] Each of the aligner 1701, attachment 1702, support 1703, connecting structure 1704, adhesive 1705, cover 1706, and handle 1707 can be directly manufactured as part of a single process as described herein. The materials of each of these components can be selected independently. Generally, the attachment 1702 will include a rigid material; the aligner 1701 will include a more flexible material; the adhesive material 1705 will include a material capable of bonding to the patient's teeth and attachments; the cover 1706, handle 1707, and connecting structure 1704 will include materials that can be broken or removed by applying a small amount of force by hand or dental instruments. Other variations including the use of composite materials and other materials as disclosed herein will be apparent to those of ordinary skill in the art.

[0226] Fig. 17B For example, Fig.17ADetailed view of support 1703 of accessory template shown. Support 1703 is shown in an enlarged form, in at least some cases, with more space than available for attachment structure 1704, thereby allowing the connection structure between accessory 1702 and support 1703 (which connection structure is formed by attachment structure 1704) to be more clearly seen. As shown, attachment structure 1704 includes one or more extensions 1714, which retain accessory 1702. After accessory 1702 is attached to the tooth, extension 1714 can be broken by applying a small amount of force on the accessory template. Extension 1714 can include some structure to assist in breakage, such as a narrow cross-sectional profile with a smaller cross-sectional area near the accessory and a large cross-sectional profile with a larger cross-sectional area away from the accessory. Alternatively or in combination, for example, the extension can include additional structure to facilitate removal, such as a lower density material or holes. For example, the material of extension 1714 can include a material suitable for breaking, such as a rigid material or a brittle material. In some embodiments, the material of the extension 1714 can absorb infrared light or radio frequency radiation at a rate greater than one or more of the attachment 1702, the template 1700, and the adhesive 1706. While the template and extension 1714 remain rigid or solid, the absorption of the infrared light or radio frequency radiation causes the extension to heat and soften or melt, allowing the attachment structure 1704 to be separated from the attachment 1702. After the extension is released from the attachment structure 1704, it may be desirable to smooth the attachment surface to remove any jagged portions or rough portions that may remain and cause discomfort to the patient or otherwise interfere with future interactions between the attachment and the aligner surface. Fig. 17B Also shown is a version that includes a cap 1706 as an annular structure of the handle, which can be used to more easily mate with a dental instrument.

[0227] In some embodiments, the material of extension 1714 may be dissolvable in a liquid at a rate greater than the dissolution rate at one or more of attachment 1702, template 1700, and adhesive 1706. In some embodiments, extension 1714 may be configured to rupture or separate from the attachment when subjected to ultrasonic vibrations.

[0228] In some embodiments, the template 1700 may define the shape of the attachment 1702. For example, the inner surface 1720 of the template 1700 may be shaped to define the outer surface 1721 of the attachment 1702. In such embodiments, the attachment 1702 may be formed directly on the inner surface 1720 of the template 1700 such that the outer surface 1721 of the template 1700 takes on the shape of the inner surface of the attachment 1702. In some embodiments, the inner surface of the template 1700 may be coated with a release agent or non-stick coating such as polytetrafluoroethylene to help separate the attachment 1702 from the template 1700 after the attachment 1702 is attached to the tooth. In some embodiments, the attachment 1702 may be formed of a UV curable material such that the template 1700 with the attachment 1702 may be placed on the patient's tooth, the attachment 1702 may then be cured in place in the template 1700 and on the patient's tooth, and the template 1700 may then be removed from the patient's tooth with the attachment 1702 remaining attached to the patient's tooth.

[0229] In order to precisely place the attachment on the patient's teeth, the attachment template can be manufactured to include a plurality of tooth-receiving cavities (e.g., at least a portion of the aligner 100 of FIG. 1 ). At least a portion of the aligner 100 includes a tooth-receiving alignment structure, such as at least a portion of the tooth-receiving cavity, for example to accommodate features of the teeth. The attachment 1702 can be manufactured in a receptacle of the aligner, such as receptacle 106. When the aligner 100 is placed on the patient's teeth 102, the tooth-receiving cavities of the aligner accommodate the patient's teeth and hold the aligner in an orientation that can be used to precisely position the attachment 1702 on the patient's teeth. After the attachment is coupled to the patient's teeth, the coupling structure 1704 can be separated from the attachment and the aligner 100 is removed, leaving the attachment 1702 attached to the patient's teeth, as shown in the attachment 104 of FIG. 1 . The attachment can be separated from the aligner 100 in many ways, such as by breaking or separating one or more weak bonds between the attachment and at least a portion of the aligner. When multiple accessories are placed, the aligner 100 may include multiple receptacles 106, each receptacle holding an accessory for one of the multiple teeth 102. In some cases, one or more tooth receiving cavities may include multiple receptacles, allowing multiple accessories to be adhered to each of the one or more teeth.

[0230] Although preferred embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided as examples only. Those skilled in the art will now appreciate many variations, changes, and substitutions without departing from the present invention. It should be understood that various alternatives to the embodiments of the invention described herein may be adopted when implementing the present invention. Various different combinations of the embodiments described herein are possible, and such combinations are considered to be part of this disclosure. In addition, all features discussed in conjunction with any one embodiment herein may be easily applicable to other embodiments herein. The accompanying claims are intended to define the scope of the present invention, and therefore cover methods and structures within the scope of these claims and their equivalents.

Claims

1. An appliance for placing an attachment on a patient's teeth, the appliance comprising: appendix; a support member, the support member including one or more attachment structures, the one or more attachment structures connected to the attachment; as well as a calibration structure coupled to the support to receive at least a portion of a tooth and position the attachment at a predetermined location on the tooth; wherein the attachment, the support and the calibration structure are integrally formed with one another, and Wherein the one or more attachment structures extend between the support and the attachment, and wherein the one or more attachment structures are configured to release the attachment from the tooth by removing the alignment structure.

2. The orthosis according to claim 1, wherein: The support, the calibration structure and the one or more connecting structures are manufactured directly together.

3. The orthosis according to claim 1, wherein: The support, the alignment structure and the one or more connecting structures are manufactured together by thermoforming.

4. The orthosis according to claim 1, wherein: The one or more attachment structures include perforations to facilitate removal of the accessory from the support.

5. The orthosis according to claim 1, wherein: The one or more attachment structures are sized and shaped to retain the accessory.

6. The orthosis according to claim 1, wherein: The support includes an inner surface shaped according to the geometry of the accessory.

7. The orthosis according to claim 1, wherein: The one or more attachment structures are sized and shaped to retain the accessory via a gap extending between the support and the accessory.

8. The orthosis according to claim 1, wherein: The one or more attachment structures include a separator sized and shaped to separate the attachment from the support.

9. The orthosis according to claim 1, wherein: The one or more attachment structures include one or more extensions extending between the support and the attachment.

10. The orthosis according to claim 9, wherein: The one or more extensions absorb infrared light at a greater rate than the calibration structure.

11. The orthosis of claim 1 further comprising an adhesive on the attachment.

12. The orthosis according to claim 11, wherein: The adhesive is a UV curable adhesive.

13. The orthosis according to claim 11, wherein: The adhesive is a pressure sensitive adhesive.

14. The orthosis according to claim 11, wherein: The adhesive and the accessory are manufactured directly together.

15. The orthosis according to claim 11, wherein: The adhesive is secured to the accessory in a separate step of manufacture.

16. The aligner of claim 11, further comprising a cover disposed on the adhesive, wherein the cover is configured to be removable from the adhesive.

17. The orthosis according to claim 16, wherein: The cover and the accessory are manufactured directly together.

18. The orthosis according to claim 1, wherein: The calibration structure includes a portion of a cavity of the calibrator; wherein the cavity is sized and shaped to receive the tooth; wherein the support member includes an extension extending from the portion to the recess; and wherein the recess is shaped to receive the accessory.

19. The orthosis according to claim 18, wherein: The portion and the extension are manufactured together.

20. An appliance for placing an attachment on a patient's teeth, the appliance comprising: appendix; a support member, the support member including one or more attachment structures, the one or more attachment structures connected to the attachment; as well as a calibration structure coupled to the support to receive at least a portion of a tooth and position the attachment at a predetermined location on the tooth; wherein the one or more attachment structures extend between the support and the attachment, and wherein the one or more attachment structures are configured to break when the alignment structure is removed from one or more of the teeth to release the attachment from the support.

21. The orthosis according to claim 20, wherein: The support, the calibration structure and the one or more connecting structures are manufactured directly together.

22. The orthosis according to claim 20, wherein: The support, the alignment structure and the one or more connecting structures are manufactured together by thermoforming.

23. The orthosis according to claim 20, wherein: The one or more attachment structures include perforations to facilitate removal of the accessory from the support.

24. The orthosis according to claim 20, wherein: The one or more attachment structures are sized and shaped to retain the accessory.

25. The orthosis according to claim 20, wherein: The support includes an inner surface shaped according to the geometry of the accessory.

26. The orthosis according to claim 20, wherein: The one or more attachment structures are sized and shaped to retain the accessory via a gap extending between the support and the accessory.

27. The orthosis according to claim 20, wherein: The one or more attachment structures include a separator sized and shaped to separate the attachment from the support.

28. The orthosis of claim 20, wherein: The one or more attachment structures include one or more extensions extending between the support and the attachment.

29. The orthosis according to claim 28, wherein: The one or more extensions absorb infrared light at a greater rate than the calibration structure.

30. The aligner of claim 20, further comprising an adhesive on the attachment.

31. The orthosis according to claim 30, wherein: The adhesive is a UV curable adhesive.

32. The orthosis according to claim 30, wherein: The adhesive is a pressure sensitive adhesive.

33. The orthosis of claim 30, wherein: The adhesive and the accessory are manufactured directly together.

34. The orthosis of claim 30, wherein: The adhesive is secured to the accessory in a separate step of manufacture.

35. The aligner of claim 30, further comprising a cover disposed over the adhesive, wherein the cover is configured to be removable from the adhesive.

36. The orthosis according to claim 35, wherein: The cover and the accessory are manufactured directly together.

37. The orthotic device of claim 20, wherein: The calibration structure includes a portion of a cavity of the calibrator; wherein the cavity is sized and shaped to receive the tooth; wherein the support member includes an extension extending from the portion to the recess; and wherein the recess is shaped to receive the accessory.

38. The orthosis according to claim 37, wherein: The portion and the extension are manufactured together.

39. A method of designing an attachment template for placing an attachment on a patient's tooth, the method comprising: determining a movement path for moving the teeth from an initial arrangement to a target arrangement; Determining a geometry of the attachment template, wherein the attachment template is configured to secure an attachment to the tooth at a determined position so that a corresponding orthodontic appliance can generate a force to move the tooth along the movement path, wherein the geometry of the attachment template comprises: a support member including a link structure connected to the attachment, and A calibration structure is connected to the support member to position the accessory at the determined position; based on the determined geometric shape, instructions are generated for directly manufacturing the accessory template, wherein the instructions include manufacturing the accessory, the support member and the calibration structure as an integrated form in a layer-by-layer manner.

40. The method of claim 39, wherein: Determining the geometry of the attachment template includes receiving a 3D dental scan of a patient's dentition.

41. The method of claim 40, wherein: Determining the geometry of the attachment template includes segmenting the 3D dental scan.

42. The method of claim 39, wherein: Determining the geometry of the accessory template includes receiving a prescription from a clinician.

43. The method of claim 39, further comprising generating a digital model of the attachment template based on the determined geometry.

44. The method of claim 39, further comprising determining a geometry of the corresponding orthodontic appliance to facilitate generation of a force to move the tooth along the movement path.

45. The method of claim 44, further comprising generating a digital model of the corresponding orthodontic appliance based on the determined geometry of the corresponding orthodontic appliance.

46. ​​The method of claim 39, wherein: Determining the geometry of the attachment template includes simulating desired tooth movement using the attachment template design.

47. The method of claim 39 further comprising sending the generated instructions to a remote location for fabrication of the accessory template.

48. The method of claim 39, wherein: The instructions include manufacturing the support, the alignment structure, and the attachment structure together in a unitary form.

49. The method of claim 39, wherein: The geometry is determined such that the attachment structure includes perforations to facilitate removal of the accessory from the support.

50. The method of claim 39, wherein: The geometry is determined such that the attachment structure is sized and shaped to retain the accessory.

51. The method of claim 39, wherein: The support includes an inner surface shaped according to the geometry of the accessory.

52. The method of claim 39, wherein: The geometry is determined such that the attachment structure is sized and shaped to retain the accessory with a gap extending between the support and the accessory.

53. The method of claim 39, wherein: The geometry is determined such that the attachment structure includes one or more extensions extending between the support and the attachment.

54. The method of claim 53, wherein: The one or more extensions absorb infrared light at a greater rate than the calibration structure.

55. The method of claim 39, wherein: The accessory template also includes an adhesive disposed on the accessory.

56. The method of claim 55, wherein: The adhesive is a UV curable adhesive.

57. The method of claim 55, wherein: The adhesive is a pressure sensitive adhesive.

58. The method of claim 55, wherein: The accessory template also includes a cover disposed over the adhesive, wherein the cover is configured to be removable from the adhesive.

59. The method of claim 39, wherein: The geometry is determined such that the calibration structure includes a portion of a cavity of the calibrator; wherein the cavity is sized and shaped to receive the tooth; wherein the support includes an extension extending from the portion to the recess; and wherein the recess is shaped to receive the accessory.

60. A method of designing an attachment template for placing an attachment on a patient's tooth, the method comprising: determining a movement path for moving the teeth from an initial arrangement to a target arrangement; Determining a geometry of the attachment template, wherein the attachment template is configured to secure an attachment to the tooth at a determined position so that a corresponding orthodontic appliance can generate a force to move the tooth along the movement path, wherein the geometry of the attachment template comprises: a support member including a link structure connected to the attachment, and an alignment structure coupled to the support to position the attachment in the determined position, wherein the coupling structure is configured to break when the alignment structure is removed from the tooth to release the attachment from the support; Instructions for directly manufacturing the accessory template are generated based on the determined geometric shape, wherein the instructions include manufacturing the geometric shape in a layer-by-layer manner into a unitary form.

61. The method of claim 60, wherein: Determining the geometry of the attachment template includes receiving a 3D dental scan of a patient's dentition.

62. The method of claim 61, wherein: Determining the geometry of the attachment template includes segmenting the 3D dental scan.

63. The method of claim 60, wherein: Determining the geometry of the accessory template includes receiving a prescription from a clinician.

64. The method of claim 60 further comprising generating a digital model of the attachment template based on the determined geometry.

65. The method of claim 60, further comprising determining a geometry of the corresponding orthodontic appliance to facilitate generation of a force to move the tooth along the movement path.

66. The method of claim 65, further comprising generating a digital model of the corresponding orthodontic appliance based on the determined geometry of the corresponding orthodontic appliance.

67. The method of claim 60, wherein: Determining the geometry of the attachment template includes simulating desired tooth movement using the attachment template design.

68. The method of claim 60 further comprising sending the generated instructions to a remote location for fabrication of the accessory template.

69. The method of claim 60, wherein: The instructions include manufacturing the support, the alignment structure, and the attachment structure together in a unitary form.

70. The method of claim 60, wherein: The geometry is determined such that the attachment structure includes perforations to facilitate removal of the accessory from the support.

71. The method of claim 60, wherein: The geometry is determined such that the attachment structure is sized and shaped to retain the accessory.

72. The method of claim 60, wherein: The support includes an inner surface shaped according to the geometry of the accessory.

73. The method of claim 60, wherein: The geometry is determined such that the attachment structure is sized and shaped to retain the accessory with a gap extending between the support and the accessory.

74. The method of claim 60, wherein: The geometry is determined such that the attachment structure includes one or more extensions extending between the support and the attachment.

75. The method of claim 74, wherein: The one or more extensions absorb infrared light at a greater rate than the calibration structure.

76. The method of claim 60, wherein: The accessory template also includes an adhesive disposed on the accessory.

77. The method of claim 76, wherein: The adhesive is a UV curable adhesive.

78. The method of claim 76, wherein: The adhesive is a pressure sensitive adhesive.

79. The method of claim 76, wherein: The accessory template also includes a cover disposed over the adhesive, wherein the cover is configured to be removable from the adhesive.

80. The method of claim 60, wherein: The geometry is determined such that the calibration structure includes a portion of a cavity of the calibrator; wherein the cavity is sized and shaped to receive the tooth; wherein the support includes an extension extending from the portion to the recess; and wherein the recess is shaped to receive the accessory.

81. A method of designing an orthodontic appliance for repositioning teeth of a patient, the method comprising: determining a movement path for moving one or more teeth from an initial arrangement to a target arrangement; determining a geometry of the orthodontic appliance, the orthodontic appliance being configured to generate a force to move the one or more teeth along the movement path, wherein the orthodontic appliance comprises: an outer shell including a plurality of tooth-receiving cavities, A convex portion is provided on the inner surface of the outer shell, wherein the projection is configured to bias inwardly from the buccal or lingual portion of the inner surface toward a corresponding buccal or lingual surface of at least one of the patient's teeth when received within the plurality of tooth receiving cavities; and Instructions for directly manufacturing the orthodontic appliance are generated based on the determined geometric shape, wherein the instructions include directly manufacturing the outer shell and the protrusion in a layer-by-layer manner as an integral form via an additive manufacturing process, and wherein the instructions include manufacturing the outer shell using a first polymer material and manufacturing the protrusion using a second polymer material.

82. The method of claim 81, wherein: The projection is configured to exhibit an amount of deformation greater than an amount of deformation exhibited by the outer shell when the projection is biased inwardly.

83. The method of claim 81, wherein: Determining the geometry of the orthodontic appliance includes taking into account attachments secured to the patient's teeth; The attachment facilitates generation of a force to move the one or more teeth along the movement path.

84. The method of claim 81, wherein: The geometry of the orthodontic appliance is determined such that the orthodontic appliance includes at least one receptacle configured to receive an attachment secured to a tooth of the patient.

85. The method of claim 81, wherein: The instructions are configured to cause a fabrication machine to form the outer shell simultaneously with the protrusion.

86. The method of claim 81 , further comprising determining a material composition for one or more of the outer shell or the protrusion.

87. The method of claim 81, wherein: Instructions for directly manufacturing the orthodontic appliance include selectively varying a thickness of the outer shell and the inner structure during the additive manufacturing process.

88. The method of claim 81, wherein: The first polymer material is a transparent material.

89. The method of claim 81, wherein: The second polymer material is a transparent material.

90. The method of claim 81, wherein: Directly manufacturing the outer shell by means of the additive manufacturing process provides a smooth outer surface on the outer shell.

91. The method of claim 81, wherein: Direct manufacturing provides a smooth outer surface on the inner surface of the outer shell.

92. The method of claim 81, wherein: The additive manufacturing process is a multi-material process that includes the use of a template; and wherein the shape of the template is designed to provide the orthodontic appliance with an appliance geometry for producing a determined force application system.

93. The method of claim 81, wherein: The method also includes sending the instructions to a manufacturing system including a 3D printer.

94. The method of claim 81, wherein: Instructions for the direct fabrication of the orthodontic appliance use a computer-aided engineering or computer-aided design program.

95. The method of claim 81, wherein: Instructions for direct fabrication of the orthodontic appliance include extruding one or more materials onto a building surface to form successive layers of a target geometry.

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