Systems and methods for additively manufacturing dental devices using photopolymer resins

Abstract

Strategies to reduce shrinkage and eventual warping of parts directly manufactured from photopolymer resins. This increases the accuracy of directly manufactured parts, which is essential for patient-specific applications. Implementation of these strategies can reduce the need for directly manufactured parts to have support structures, which can reduce pre- and post-processing steps and facilitate easier procedures for production-level scale of additive manufacturing.

Description

[0001] Related Applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 879,845, filed on July 29, 2020, entitled “STRATEGIES TO COMBAT THE EFFECT OF SHRINKAGE INPHOTOPOLYMER RESINS,” under 35 U.S.C. §119(e), the entire contents of which are incorporated herein by reference in their entirety. Background Art

[0003] Additive manufacturing has been used in many fields. One promising application is the manufacture of oral appliances and components. However, some aspects of additive manufacturing make this method less than ideal for at least some oral appliances. For example, directly manufactured polymers may have less than ideal strength and may warp in at least some cases.

[0004] Typically, when directly manufacturing a photopolymer, the amount of light energy delivered to the initial layer can be significantly greater than the amount of light energy used to manufacture the remainder of the component. The amount of light energy is related to the amount of polymer crosslinking in the directly manufactured photopolymer. The light energy can be increased for the first layer to increase adhesion between the photopolymer and the manufacturing platform. If the initial layer (also known as the "burn in" layer) does not provide sufficient adhesion, the component may not be successfully manufactured. The light energy can also be increased for the initial layer to compensate for inaccuracies in the initial leveling process, in which the application platform is less than ideally aligned with the light beam component used to manufacture the layer. The light energy can be reduced for the remaining layers, which can be directly manufactured with a similar amount of light energy.

[0005] In at least some cases, varying the amount of light energy between the layers may result in warping of the component. Delivering different amounts of light energy to different layers generally results in different amounts of crosslinking in the layers. Photopolymers may shrink when cured, and the amount of shrinkage may be related to the amount of crosslinking. Different amounts of crosslinking and curing may produce different levels of shrinkage within the component. Different amounts of shrinkage may result in the development of internal stresses within the component, which may manifest as warping or curling.

[0006] This effect may be further enhanced for directly manufactured parts, where the lateral dimension of the part along the build platform area is larger than the thickness of the part along the manufacturing direction. In addition, structures located away from the build platform may experience movement when the base structure warps. In order to reduce these effects, the part can be suspended away from the build platform and fixed there by thin columns connecting the part to the platform. However, such columns may take additional time to manufacture and may be removed in subsequent manufacturing steps, thereby increasing the time and complexity of the manufacturing process.

[0007] In view of the above, there is a need for improved methods and apparatus for deposition manufacturing and components that can be manufactured with reduced warpage. Ideally, such methods, apparatus, and components will overcome at least some of the above limitations of previous methods. Summary of the invention

[0008] The methods and apparatus disclosed herein allow for the manufacture of oral appliances, such as dental devices, with fewer steps and reduced deformation, such as warping. The methods and apparatus allow for direct manufacture of oral devices that reduce warping when manufactured directly to a build platform. In some embodiments, an oral appliance includes an elongated structure having a surface manufactured directly on a platform of an additive manufacturing machine, such as a 3D printer, wherein the oral appliance includes one or more structures for reducing deformation and reducing manufacturing steps, such as removal of standoffs.

[0009] In a first aspect, an oral device comprises: a plurality of layers of cured photopolymer material forming a body, wherein the body comprises an upper surface and a substantially planar lower surface, wherein at least one layer of the plurality of layers inhibits warping of the body.

[0010] In some embodiments, the oral device further comprises at least one attachment for a tooth and at least one support, wherein the at least one attachment for a tooth is coupled to the body via the at least one support.

[0011] In some embodiments, each of the plurality of layers has been cured to have a similar amount of polymer crosslinks. In some embodiments, each of the plurality of layers has an amount of polymer crosslinks that is within a range of about 90% and 110% of an average amount of polymer crosslinks of the plurality of layers. In some embodiments, each of the plurality of layers has a similar amount of polymer crosslinks suitable for adhering to a build platform.

[0012] In some embodiments, a first layer of a planar surface and a second layer spaced apart from the first layer each have an amount of polymer crosslinks that is greater than an amount of polymer crosslinks of an inner plurality of layers between the first layer and the second layer. The first layer and the second layer may have similar amounts of polymer crosslinks, and each of the inner plurality of layers may have similar amounts of polymer crosslinks. In some embodiments, each of the inner plurality of layers has an amount of polymer crosslinks that is between 90% and 110% of an average amount of polymer crosslinks of the inner plurality of layers, and the first layer and the second layer each have an amount of polymer crosslinks that is between 90% and 110% of an average amount of polymer crosslinks of the first layer and the second layer, wherein the average of the inner plurality of layers is at least about 10% less than the average of the first layer and the second layer.

[0013] In some embodiments, the body has a width, a length, and a thickness, and the thickness is at least 0.25 times the length of the body. In some embodiments, the thickness is no more than 0.25 times the length of the body.

[0014] In some embodiments, the lower surface includes a platform pattern defining a plurality of grooves in a substantially planar surface. The pattern may include one or more of a checkerboard pattern, a tile pattern, and a stripe pattern. In some embodiments, the platform covers between 25 percent and 75 percent of the surface area defined by the outer perimeter of the platform pattern. In some embodiments, the platform includes a taper that widens from the face of the platform toward the upper surface.

[0015] In some embodiments, the lower surface has a pattern including regions of resin having a higher amount of polymer cross-links and regions of resin having a lower amount of polymer cross-links.

[0016] In some embodiments, the body comprises an attachment for a tooth.The attachment for a tooth may comprise a substantially flat surface for engaging a tooth, and the substantially flat surface comprises a substantially planar surface.

[0017] In some embodiments, the body comprises an elongated structure operable to position an attachment for a tooth. In some embodiments, the body has a length and a width, and the length is at least four times the width. The oral device may include a registration structure for positioning the oral device and a support structure for coupling the registration structure to the body, wherein the registration structure and the attachment are coupled to opposite sides of the oral device. In some embodiments, at least one layer for inhibiting warping extends through two or more of the body, the support structure, or the support. In some embodiments, the solidification layer extends through the attachment and the registration structure.

[0018] In another aspect, a method of manufacturing an oral device includes forming a plurality of resin layers to form a body having an upper surface and a planar lower surface. The substantially planar lower surface is fabricated directly to a platform, and at least one of the plurality of layers inhibits warping of the body.

[0019] In some embodiments, the oral device includes at least one attachment and at least one support coupling the attachment to a body, and the method further includes directly manufacturing a plurality of support layers for forming the support and a plurality of attachment layers for forming the attachment.

[0020] In some embodiments, the method further comprises manufacturing each of the plurality of layers to have the same amount of polymer crosslinks. In some embodiments, the method further comprises manufacturing a first layer directly at the surface of the plane and manufacturing a second layer directly at the upper surface, the first layer and the second layer having a greater amount of polymer crosslinks than the inner plurality of layers between the first layer and the second layer. In some embodiments, the method further comprises manufacturing the first layer and the second layer directly to have a similar amount of polymer crosslinks. In some embodiments, the method further comprises manufacturing each of the inner plurality of layers directly to have a similar amount of polymer crosslinks.

[0021] In some embodiments, the body has a width, a length, and a thickness, and the thickness is at least 0.25 times the length of the body.

[0022] In some embodiments, the method further comprises directly manufacturing the lower surface to have a platform pattern. The pattern may include one or more of a checkerboard pattern, a tile pattern, or a strip pattern. In some embodiments, the method further comprises directly manufacturing the platform to have an area between 25 percent and 75 percent of a perimeter defined by a plurality of platforms. In some embodiments, the method further comprises directly manufacturing the platform to have a taper that widens from the face of the platform toward the upper surface. In some embodiments, the lower surface has a pattern comprising a resin region with a high polymer cross-linking amount and a resin region with a lower polymer cross-linking amount. In some embodiments, the pattern comprises one or more of a checkerboard pattern, a tile pattern, or a strip pattern.

[0023] Incorporated by Reference

[0024] All patents, applications, and publications mentioned and identified herein are incorporated by reference in their entirety, and should be deemed to be fully incorporated by reference even if mentioned elsewhere in this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] A better understanding of the features, advantages, and principles of the present disclosure will be obtained by referring to the following detailed description and accompanying drawings which set forth illustrative embodiments, in which:

[0026] Figure 1 An example of a dental apparatus for positioning an orthodontic attachment according to some embodiments is shown;

[0027] Figure 2 Attached to a tooth according to some embodiments Figure 1 Examples of dental devices;

[0028] Figure 3 shows an example of a dental device having a registration structure for positioning the dental device relative to a set of teeth according to some embodiments;

[0029] Figure 4 An example dental apparatus for positioning an orthodontic attachment on a set of teeth is shown according to some embodiments;

[0030] Figure 5 shows an example of a dental device having a registration structure for positioning the dental device on a set of teeth according to some embodiments;

[0031] Figure 6 A dental apparatus according to some embodiments is shown;

[0032] Figure 7 shows example layers of a directly manufactured dental device according to some embodiments;

[0033] Figure 8 shows example layers of a directly manufactured dental device according to some embodiments;

[0034] Fig. 9 shows example layers of a directly manufactured dental device according to some embodiments;

[0035] Fig.10 shows example layers of a directly manufactured dental device according to some embodiments;

[0036] Fig.11 shows example layers of a directly manufactured dental device according to some embodiments;

[0037] Fig.12 shows example layers of a directly manufactured dental device according to some embodiments;

[0038] Fig.13 shows example layers of a directly manufactured dental device according to some embodiments;

[0039] Fig.14 shows a schematic diagram of a direct manufacturing machine according to some embodiments;

[0040] Fig.15 A schematic diagram showing a method for manufacturing a dental device according to some embodiments is shown;

[0041] Fig.16 A dental apparatus according to some embodiments is shown;

[0042] Fig.17 According to some embodiments Fig.16 Cross-section of a dental device;

[0043] Fig.18 According to some embodiments Fig.16 A cross-section of a dental device; and

[0044] Fig.19 A method of additively manufacturing a dental device according to some embodiments is shown. DETAILED DESCRIPTION

[0045] The following detailed description provides a better understanding of the features and advantages of the invention described in the present disclosure according to the embodiments disclosed herein. Although the detailed description includes many specific embodiments, these embodiments are provided only by way of example and should not be construed as limiting the scope of the invention disclosed herein. The methods, devices and dental braces disclosed herein are well suited for combination with many dental braces and applications, such as aligners, retainers, palatal expanders, brackets for placing attachments on multiple teeth, attachments for being connected to teeth, night guards, functional braces and directly manufactured aligner thermoforming molds. The methods, devices and braces disclosed herein are well suited for direct manufacturing using deposition manufacturing (sometimes referred to as additive manufacturing or 3D printing), fused deposition modeling, stereolithography (SLA), digital light projector (DLP) printing, continuous DLP, inkjet spraying and metal printing. In addition, the methods and devices currently disclosed are well suited for additive manufacturing of different materials onto a single brace, such as inkjet printing with a variety of different materials to manufacture braces including a variety of different materials.

[0046] In some embodiments, the orthodontic appliances herein (or portions thereof) may be produced using direct manufacturing, such as additive manufacturing techniques (also referred to herein as "3D printing"). Additive manufacturing techniques can be categorized as follows: (1) slot photopolymerization (e.g., stereolithography), in which an object is constructed 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, including but 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, including but 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 mesh forming, directed light manufacturing, direct metal deposition, and 3D laser cladding. For example, stereolithography can be used to directly manufacture one or more aligners described herein. In some embodiments, stereolithography includes selective polymerization of a photosensitive resin (e.g., a photopolymer) using light (e.g., ultraviolet light) according to a desired cross-sectional shape. The object geometry can be built up in a layer-by-layer manner by sequentially polymerizing multiple object cross sections. As another example, the braces herein can be directly manufactured using selective laser sintering. In some embodiments, selective laser sintering involves using a laser beam to selectively melt and fuse layers of powdered material according to a desired cross-sectional shape in order to build the object geometry. As yet another example, the braces herein can be directly manufactured by fused deposition molding. In some embodiments, fused deposition molding involves melting and selectively depositing filaments of thermoplastic polymers in a layer-by-layer manner to form an object. In yet another example, the braces herein can be directly manufactured using material jetting. In some embodiments, material jetting involves jetting or extruding one or more materials onto a build surface in order to form a continuous layer of the object geometry.

[0047] In some embodiments, the direct manufacturing method provided herein builds the object geometry in a layer-by-layer manner, wherein continuous layers are formed in discrete building steps. Alternatively or in combination, a direct manufacturing method that allows the continuous construction of the object geometry can be used, referred to herein as "continuous direct manufacturing". Various types of continuous direct manufacturing methods can be used. As an example, in some embodiments, the rectifier of this article is manufactured using "continuous liquid interphase printing", in which the object is continuously built from a container of photopolymerizable resin by forming a gradient of partially cured resin between the building surface of the object and a "dead zone" that inhibits polymerization. In some embodiments, a semipermeable membrane is used to control the delivery of a photopolymerization inhibitor (e.g., oxygen) to the dead zone so as to form a polymerization gradient. Continuous liquid interphase printing can achieve a manufacturing speed that is about 25 times to about 100 times faster than other direct manufacturing methods, and can achieve a speed that is about 1000 times faster by combining a cooling system. Continuous liquid interphase printing is described in U.S. Patent Publication Nos. 2015 / 0097315, 2015 / 0097316, and 2015 / 0102532, the disclosures of each of which are incorporated herein by reference in their entirety.

[0048] As another example, a continuous direct manufacturing method can achieve continuous construction of object geometry by continuously moving the building platform (e.g., along the vertical or Z direction) during the irradiation phase, so that the hardening depth of the irradiated photopolymer is controlled by the movement speed. Thus, continuous polymerization of the material on the building surface can be achieved. Such a method is described in U.S. Patent No. 7,892,474, the disclosure of which is incorporated herein by reference in its entirety.

[0049] In another example, a continuous direct manufacturing method can involve extruding a composite material consisting of a curable liquid material around a solid strand. The composite material can be extruded along a continuous three-dimensional path to form an object. Such a method is described in U.S. Patent Publication No. 2014 / 0061974, the disclosure of which is incorporated herein by reference in its entirety.

[0050] In yet another example, a continuous direct manufacturing method utilizes a "spiral lithography" method in which a liquid photopolymer is cured by focused radiation while a build platform is continuously rotated and raised. Thus, object 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.

[0051] The direct manufacturing method provided herein is compatible with various materials, including but not limited to one or more of the following: polymer matrix, 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, elastic alloy, thermoplastic elastomer (TPE), thermoplastic vulcanizate (TPV) elastomer, polyurethane elastomer, block copolymer elastomer, polyolefin hybrid 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, cross-linking, etc.) to form an orthodontic appliance or a portion thereof. The material properties before curing may be different from the material properties after curing. Once cured, the materials herein may exhibit sufficient strength, stiffness, durability, biocompatibility, etc. to be used in orthodontic braces. The post-curing properties of the material used may be selected based on the desired properties of the corresponding parts of the braces.

[0052] In some embodiments, the relatively rigid portion of the orthodontic brace can be formed by direct manufacturing using one or more of the following materials: polyester, copolyester, polycarbonate, thermoplastic polyurethane, polypropylene, polyethylene, polypropylene and polyethylene copolymers, acrylic, cyclic block copolymers, polyetheretherketone, polyamide, polyethylene terephthalate, polybutylene terephthalate, polyetherimide, polyethersulfone and / or polytrimethylene terephthalate.

[0053] 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, elastic alloys, thermoplastic elastomers (TPE), thermoplastic vulcanizate (TPV) elastomers, polyurethane elastomers, block copolymer elastomers, polyolefin blended elastomers, thermoplastic copolyester elastomers and / or thermoplastic polyamide elastomers.

[0054] 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 involves forming an object from multiple materials simultaneously in a single manufacturing step using the same manufacturing machine and method. For example, a multi-tip 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. Pat. 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 can involve forming an object from multiple materials in multiple sequential manufacturing steps. For example, a first portion of an object can be formed from a first material according to any direct manufacturing method herein, and then a second portion of the object can be formed from a second material according to the method herein, and so on, until the entire object has been formed. The relative arrangement of the first portion and the second portion can be varied as desired, for example, the first portion can be partially or completely encapsulated by the second portion of the object. The sequential manufacturing steps can be performed using the same manufacturing machine or different manufacturing machines, and can be performed using the same manufacturing method or different manufacturing methods. For example, a sequential multi-fabrication process may involve forming a first portion of an object using stereolithography and forming a second portion of the object using fused deposition modeling.

[0055] Direct manufacturing can provide various advantages over other manufacturing methods. For example, compared to indirect manufacturing, direct manufacturing allows orthodontic braces to be produced without utilizing 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 brace geometries that are difficult to create using alternative manufacturing techniques, such as braces with very small or fine features, complex geometries, undercuts, interproximal structures, shells with variable thicknesses, and / or internal structures (e.g., for improving strength while 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 of about 5 μm to about 50 μm, or in a range of about 20 μm to about 50 μm.

[0056] The direct manufacturing techniques described herein can be used to produce braces with substantially isotropic material properties (e.g., substantially the same or similar strength in all directions). In some embodiments, the direct manufacturing methods herein allow the production of orthodontic braces whose strength varies by no more than about 25%, about 20%, about 15%, about 10%, about 5%, about 1%, or about 0.5% along all directions. In addition, the direct manufacturing methods herein can be used to produce orthodontic braces at a faster speed than other manufacturing techniques. In some embodiments, the direct manufacturing methods herein allow the production of orthodontic braces within 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. Such manufacturing speeds allow for rapid "chairside" production of custom braces, such as during routine appointments or examinations.

[0057] In some embodiments, the direct manufacturing methods described herein implement process control over various machine parameters of the direct manufacturing system or device to ensure that the resulting aligner is manufactured with high precision. Such precision can be beneficial in ensuring that the desired force system is accurately delivered to the teeth to effectively cause tooth movement. Process control can be implemented to take into account process variability caused by multiple sources (such as material properties, machine parameters, environmental variables, and / or post-processing parameters).

[0058] The material properties can vary according to the properties of the raw materials, the purity of the raw materials and / or the process variables during the raw material mixing. In many embodiments, the resin or other materials used for direct manufacturing should be manufactured with strict process control to ensure that the changes in optical properties, material properties (e.g., viscosity, surface tension), physical properties (e.g., modulus, strength, elongation) and / or thermal properties (e.g., glass transition temperature, heat distortion temperature) are very small. The process control for the material manufacturing process can be achieved by screening the physical properties of the raw materials and / or controlling temperature, humidity and / or other process parameters during the mixing process. By implementing the process control for the material manufacturing program, the reduced variability of the process parameters of each batch of materials and more uniform material properties can be achieved. As further discussed herein, the residual variability of material properties can be compensated with the process control on the machine.

[0059] 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. As part of process control on the manufacturing machine, these machine parameters may be monitored and adjusted regularly (e.g., some parameters every 1-x layers, some parameters after each build). Process control may be achieved by including sensors on the machine that measure power and other beam parameters every 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.). In addition, material properties and / or light characteristics may be provided to the manufacturing machine, and the machine process control module may use these parameters to adjust machine parameters (e.g., power, time, grayscale, etc.) to compensate for changes in material properties. By implementing process control on the manufacturing machines, reduced variability in aligner accuracy and residual stresses can be achieved.

[0060] In many embodiments, environmental variables (e.g., temperature, humidity, sunlight or exposure to other energy / curing sources) are maintained within tight ranges to reduce variations in aligner thickness and / or other properties. Optionally, machine parameters can be adjusted to compensate for environmental variables.

[0061] 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 consistency of the support removal process. These parameters may be measured and adjusted as part of a process control scheme. In addition, the physical properties of the brace may be changed by modifying the post-processing parameters. Adjusting the post-processing machine parameters may provide another way to compensate for the variability of material properties and / or machine properties.

[0062] Although specific reference is made to oral components (such as orthodontic devices and molds for orthodontic devices), the methods and apparatus disclosed herein will find application in many fields, such as implantable devices, cardiology, orthopedics, and general product design within the healthcare industry. It may also be used in other industries, such as aviation, automotive, particularly for component manufacturing, etc.

[0063] Figure 1An exemplary dental device 10 for positioning an attachment 12 on a patient's teeth 13 is shown. As described herein, one or more components of the device 10 may be directly manufactured to inhibit warping, and as described herein, the device 10 may include at least one component directly manufactured with at least one layer to inhibit warping. The dental device 10 may include a body 16, an attachment 12, and one or more supports 14. The size and shape of the dental device 10 may be formulated to be positioned on multiple teeth of a patient present in the upper or lower jaw. The body 16 may include many suitable structures for placement on one or more teeth of the patient, such as a thin shell polymer aligner, which includes multiple tooth receiving cavities that are sized and shaped to receive the patient's teeth. The dental device 10 may be coupled to the attachment 12 via one or more supports 14, and the body 16 may include an opening to expose at least a portion of the teeth 13 during placement of the attachment 12. In some embodiments, the dental device 10 and the attachment 12 may be formed as a single component. For example, as described herein, the dental device 10 and the attachment 12 may be directly manufactured simultaneously using additive manufacturing. In other embodiments, some components of the dental device 10 are manufactured separately and coupled together prior to placement on the patient's teeth. For example, a free-standing attachment 12 can be coupled to the support 14 using conventional joining techniques, such as plastic welding or adhesives, prior to placement of the dental device 10 on the patient's teeth. Coupling the attachment 12 to the body 16 prior to placement on the patient's teeth can allow the attachment to be accurately positioned on the patient's teeth. Once the attachment 12 has been properly positioned on the patient's teeth, the attachment 12 can be adhered to the teeth. The attachment 12 can be used to apply beneficial forces to the teeth using a polymer shell dental brace. For example, the attachment can be used with a polymer shell dental brace commercially available from Align Technology, Inc. Use together with treatment.

[0064] The described device and method are suitable for the direct production of a dental device 10 with the attachment 12 as a single component, for the direct production of a dental device 10 with the attachment 12 as a separate component, or for the direct production of an attachment 12 .

[0065] Figure 2 An attachment 12 is shown secured to a patient's tooth 13. The attachment 12 can be used as an anchor during orthodontic procedures and can enhance the performance of an orthodontic device in tooth movement. In some examples, the attachment 12 can be bonded to the tooth by an adhesive. The surface of the attachment 12 can include a smooth surface to bond to the tooth, or have a texture to enhance the bond between the tooth and the attachment 12. The surface bonded to the tooth can have an attachment surface that is complementary to the surface of the tooth to which it is bonded.

[0066] Figure 3An exemplary dental device 10 is shown placed on a patient's tooth. As described herein, one or more components of device 10 can be directly manufactured to inhibit warping, and as described herein, device 10 can include at least one component manufactured with at least one layer to inhibit warping. Device 10 can include a surface 11 that has been directly manufactured on, for example, a stereolithography 3D printer. Surface 11 can be located on a side of the dental device opposite the tooth engagement surface of the device. Surface 11 can be located on the occlusal surface of the tooth. During manufacturing, surface 11 can be manufactured on a build platform (sometimes referred to as a manufacturing platform). In some embodiments, as described herein, surface 11 can include one or more running-in layers. As described herein, at least one layer that inhibits warping can include structures (e.g., stress relief structures) located in the running-in layer or other layers of the device, or structures located on a different layer away from surface 11.

[0067] The dental device 10 includes: a body 16; a plurality of attachments 12; a plurality of supports 14, coupling the attachments 12 to the body 16; a plurality of registration structures 18; and a plurality of support structures 20, coupling the registration structures 18 to the body 16. The body 16 may include one or more elongated structures 17. The body 16 may include a single U-shaped component that includes one or more elongated structures 17, or it may include a plurality of elongated structures 17 that may be joined together. The position of each of the plurality of attachments on each tooth may be determined by a professional treatment staff using a planning software, and the device 10 may be directly manufactured according to the position determined using the treatment planning software.

[0068] In use, the body 16 can provide a reference structure for positioning the attachment 12 relative to the patient's teeth, and the alignment structure 18 can secure and position the body 16 relative to the patient's teeth. Although the alignment structure can be placed on the patient's teeth in many ways, in some embodiments, the alignment structure is located on the body 16 for placement at a mesial position on the patient's teeth. The dental device 10 can be positioned in the patient's mouth, wherein the alignment structure 18 contacts the patient's teeth to orient the attachment 12 in a predetermined position. With the attachment 12 in the correct position, the attachment 12 can be coupled to the teeth. Once the attachment 12 is coupled to the teeth, the support 14 can be removed from the attachment 12, thereby releasing the dental device 10 from the patient's teeth. The dental device 10 can then be removed from the patient's mouth, allowing the attachment 12 to be coupled to the patient's teeth in a desired position (e.g., a predetermined position).

[0069] In some embodiments, the elongated body 16 includes one or more structures for reducing deformation, as described herein, to place the attachment 12 in an appropriate position on the patient's tooth. For example, the one or more elongated structures 17 of the body 16 may include one or more structures for reducing deformation, as described herein, to place the attachment 12 in an appropriate position on the patient's tooth. Although the one or more structures for reducing deformation can be configured in many ways, in some embodiments, the surface 11 includes multiple stress relief structures, such as multiple platforms. Alternatively or in combination, the elongated structure 17 may include a layer for inhibiting warping of the surface 11, such as a relative layer having a similar amount of cross-linking and exposure as the running-in layer of the surface 11.

[0070] Figure 4 and Figure 5 An exemplary dental apparatus 10 is shown in relation to a 3D digital model 25 of a patient's teeth, and Figure 6 A portion of a dental device 10 is shown in a freestanding configuration. The 3D digital model 25 can be used as a basis for generating instructions to directly manufacture one or more components of the dental device 10, and in some embodiments, directly manufacture the entire dental device 10. As described herein, one or more components of the device 10 can be directly manufactured to inhibit warping, and as described herein, the device 10 can include at least one component that is directly manufactured with at least one layer to inhibit warping. The device 10 can include a surface 11 that has been directly manufactured on an additive manufacturing device (such as a 3D printer). Prior to directly manufacturing the dental device 10, these structures for reducing warping can be identified on the 3D model. The surface 11 can be located in a directly manufactured layer on a surface or device opposite to the tooth engagement side of the device, or between the tooth engagement side of the device and the tooth engagement side or surface of the device, and the surface 11 can be identified on the model 25. As described herein, the surface 11 can include one or more running-in layers, and the model 11 is constructed accordingly. As described herein, at least one layer for inhibiting warping can include structures (e.g., stress relief structures) located in the running-in layer, or structures located on a different layer away from the surface 11. Each of these structures may be identified on the 3D model prior to direct manufacturing of the dental device 10. For example, one or more of the elongated structures 17 may be configured to be directly manufactured with structures for inhibiting warping, as described herein.

[0071] The dental device 10 includes a body 16 , a plurality of attachments 12 , a plurality of supports 14 coupling the attachments 12 to the body 16 , a registration structure 18 , and a support structure 20 coupling the registration structure 18 to the body 16 .

[0072] Figure 4 A model 25 of a patient's teeth and a vestibular view of the dental apparatus 10 are shown. Figure 4As shown, the size and shape of the dental device 10 are configured to complement the patient's teeth. The body 16 may include a recess 22 that receives the occlusal surface of at least one tooth. The recess 22 may be shaped to complement the occlusal surface of the patient's teeth. A plurality of supports 14 may be coupled to the body 16 and extend around the attachment 12. A plurality of extensions 24 may extend from the supports 14 to the attachment 12. The extensions 24 may have a weaker structure than the supports 14, such that the extensions 24 are breakable at the connection points with the attachment 12. In use, after the attachment 12 is coupled to the teeth, the extensions 24 may be broken at the connection points, and the dental device 10 may be removed from the patient's mouth, leaving the attachment 12 in place and coupled to the patient's teeth.

[0073] Figure 5 A lingual view of the patient's teeth is shown, and registration structures 18 are shown interacting with the patient's teeth. Each registration structure 18 is coupled to body 16 via support structure 20. Registration structures 18 and recesses 22 can secure dental device 10 within the patient's mouth to position attachment 12 at a predetermined location.

[0074] Figure 6 The dental device 10 is shown after direct manufacture of the device 10. The dental device 10 can be formed from a single structure, or can be formed from multiple structures coupled together. For example, each portion of the body 16 having a recess 22 for receiving a tooth can be formed separately from the remaining portions so that elements of the body 16 are engaged by the tooth receiving portion. The spacing between the attachment 12 and the registration structure 18 can be equal to the width of the patient's teeth at a particular location, or in some examples, the spacing can be slightly less than the width of the patient's teeth so that elastic deformation of the support 14 or support structure 20 is used to fit the dental device 10 on the patient's teeth. The resulting inward bias can help position and retain the dental device 10 on the patient's teeth.

[0075] Figure 7 A cross-section of an example dental device 10 is shown showing an exemplary directly manufactured resin layer 26. The dental device 10 is shown having a body 32 and a structure 34 extending away from the body 32. For example, the structure 34 may include one or more of the support 14, the support structure 20, or one or more elongated structures 17. Although a single structure 34 is shown, the dental device may include multiple structures 34 extending from the body 32, for example. In some embodiments, the dental device may not have a support structure. In some embodiments, the dental device 10 may be an orthodontic aligner, and the layer 26 may be a layer forming the orthodontic aligner, including the sidewalls of one or more tooth receiving cavities.

[0076] Dental device 10 includes a plurality of directly manufactured layers 26 in succession. A first layer 28 is manufactured directly on a build platform 30, and each successive layer is manufactured directly on each previous layer. If build platform 30 is referred to as an XY plane and the Z axis extends away from build platform 30, then Figure 7 The cross-section of is shown along a plane perpendicular to the build platform 30 and parallel to the Z axis, and shows that each successive layer is built along the Z direction. Therefore, as each directly manufactured resin layer is formed, each layer increases the size of the dental device along the Z direction.

[0077] exist Figure 7 In an example of, the first layer 28 may include the surface 11 of the dental device. In an orthodontic aligner, the first layer 28 may be the occlusal or incisor surface of the orthodontic aligner, and the device may be manufactured by directly manufacturing each layer of resin with a similar amount of crosslinking to reduce deformation. In some embodiments, the amount of crosslinking may be controlled by adjusting the amount of light energy used to cure the resin. In some examples, the amount of light energy is selected to be just above the amount of light energy that adheres the first layer 28 to the building platform 30. The dose may be delivered at a rate of 0.1W / cm^2. In some embodiments, "about" refers to an amount between 95% and 105% of the amount of light energy that adheres the first layer to the building platform. In some embodiments, the amount may be, for example, between 90% and 110% of the amount of light energy to reduce deformation. In some embodiments, the layer may be cured with an energy dose sufficient to cure the resin to its green strength. In some embodiments, the layer may be cured with a dose between 95% and 105% or between 90% and 110% of the green strength dose. In some embodiments, the layer may be cured with a dose less than the green strength dose. In some embodiments, the first layer can be cured with a dose sufficient to adhere the layer to the build platform, and subsequent layers can be cured with a dose that cures the resin to its green strength. In some embodiments, subsequent layers can be cured to a dose less than its green strength, such as at least 5% less or 10% less.

[0078] Figure 8A cross section of an example dental device 10 is shown, showing an example layer for inhibiting warping of one or more components of the device (such as body 16). In this example, a first layer 28 is directly manufactured using an amount of light energy selected to be higher than the minimum amount used to adhere the first layer 28 to the building platform 30. Subsequent layers are cured with an amount of light sufficient to adhere the layer to the first layer 28, but the amount of light remains consistent as the layers are added. For example, the first layer 28 can be cured using a dose of light sufficient to adhere the first layer to the building platform provided at a rate of 0.15W / cm^2, and subsequent layers can be cured using a dose less than the dose of the first layer provided at a rate of 0.05W / cm^2. In some examples, each subsequent layer can have an amount of light or dose that is 20% less than the amount of light used to cure the first layer. In some examples, each subsequent layer can have an amount of light between 95% and 105% of the median amount of light for the subsequent layer. As described herein, the method can be combined with a method for inhibiting deformation.

[0079] Fig. 9 A cross-section of an example dental device 10 is shown, illustrating example layers for inhibiting warping of the body 16. Fig. 9 In the example of , first layer 28 is cured using an amount (dose) of light energy sufficient to adhere first layer 28 to build platform 30. Another layer 36 can be directly manufactured similar to first layer 28 to offset the effects of stress of first layer 28. After first layer 28 is cured, multiple subsequent layers 29 are cured using an amount of light energy less than the amount used to cure first layer 28. Layer 36 can be directly manufactured with an amount of light similar to layer 28. Layer 28 can include an outer layer 36 of body 16 opposite to first layer 28. Layer 36 can be cured using an amount of light energy similar to the amount of first layer 28. In some examples, for example, a layer between first layer 28 and outer layer 36 can be manufactured with an amount of light energy that is 20% of the amount of light energy used to directly manufacture first layer 28 and outer layer 36. Although layer 36 is shown as an outer layer, layer 36 can include an inner layer located at a sufficient distance from layer 28 to reduce deformation. In some embodiments, layer 36 can be an intermediate layer between the first layer and the last layer.

[0080] In some examples, each layer between the first layer 28 and the outer layer 36 can be manufactured using a similar amount of light energy. In other examples, the amount of light energy used for the layers can vary, but have a symmetrical relationship about the centerline 38 of the body 16. For example, after the first layer 28, each subsequent layer can be cured using an amount of light energy that is lower than the previous amount until the intermediate layer or centerline 38 between the first layer 28 and the layer 36. Each subsequent layer can be cured with an amount of light energy similar to the opposite layer relative to the intermediate layer or centerline 38. For example, if the first layer 28 is cured with an amount of a first dose, the second layer can be cured with a dose of light energy that is 20% lower than the first dose. The third intermediate layer can be cured with an amount of light energy that is 50% lower than the first dose, the fourth layer opposite the second layer relative to the intermediate layer or centerline 38 can be cured with an amount of light energy that is 20% lower than the first dose, and the outer layer 36 opposite the first layer 28 relative to the centerline 38 can be cured with the first dose of light energy. In some embodiments, each layer from the first layer to the midline can be cured with a dose that is gradually reduced by 5%, 6%, 7%, 8%, 9%, 10%, 15% or 20% of the first dose, and each layer from the midline to the outer layer can be cured with a dose that is gradually increased by 5%, 6%, 7%, 8%, 9%, 10%, 15% or 20% of the first dose.

[0081] Although this example lists only five layers, it will be appreciated by those of ordinary skill in the art that symmetrical patterns can be applied to any number of layers. In some embodiments, each successive layer between the first layer and the center line or middle layer is cured with a continuously lower amount of energy, and each successive layer between the center line or middle layer and the outer layer is cured with a larger amount of energy. In some embodiments, each subsequent layer between the first layer and the center line or middle layer is cured with 5%, 6%, 7%, 8%, 9%, 10%, 15% or 20% less than each previous layer. In some embodiments, each layer between the center line or middle layer and the outer layer is cured with 5%, 6%, 7%, 8%, 9%, 10%, 15% or 20% less than each subsequent layer.

[0082] Fig.10An example of a layer 40 of a body 16 having a pattern for inhibiting warping is shown. The layer 40 is viewed perpendicular to the build platform 30 and may represent a view of a single layer. In some embodiments, the layer 40 is shown as a curing mask for a layer. In some examples, a single layer may be made using the pattern shown, or in other examples, the pattern may be repeated for multiple layers to form a platform. The layer 40 includes a first region 42 of a resin cured with a first dose or amount of light suitable for adhering to the build platform 30 or a previous layer and a second region 44 of a resin cured or maintained uncured with a second dose or lower amount of light. In some embodiments, the mask depicts a region 42 where light energy is provided to cure the layer and a region 44 where less light energy or no light energy is provided to cure the layer. The first region 42 may include the surface 11 of the dental device 10. In some examples, instead of a resin cured with a low amount of light, the resin may be uncured so that when the part is removed from the build platform 30, no resin remains in the second region. Fig.10 The pattern is such that first regions 42 and second regions 44 alternate in a checkerboard pattern. The pattern may cover the entire surface of the body that contacts build platform 30, or in some examples, the pattern may cover limited areas. For example, these areas may be located on the first layer. In some embodiments, each layer formed by the object may be formed using a checkerboard or alternating mask, such as Fig.10 As shown, for the internal structure of the object. In some embodiments, the fill percentage between the first region 42 and the second region 44 can be 50%, wherein the total area of ​​the first region and the second region is equal. In some embodiments, the fill percentage can be 10%, wherein the first region occupies 10% of the cross-sectional area of ​​the layer, and the second region 44 can occupy 90% of the cross-sectional area of ​​the layer. In some embodiments, the first region may comprise an amount equal to or greater than 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% of the area of ​​the layer, while the second region comprises an amount equal to or greater than 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% of the area of ​​the layer. In embodiments where the first region of a layer is equal to or greater than 50%, the layer is continuous because the larger solidified region is connected across the layer, whereas in a layer where the checkerboard pattern of the layer includes less than 50% of the first region, the first layer may not be connected across the layer and the layer is discontinuous.

[0083] In some embodiments, the layer may include a third region cured at a third dose. Similar to the first and second layers, the third region may include an area equal to or greater than 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95% of the layer.

[0084] Fig.11 An example layer or cure mask 40 of body 16 is shown having a pattern suitable for inhibiting warping of dental device 10 . Fig.11 The pattern includes first regions 42 of resin cured with a high amount of light (such as a dose sufficient for the resin to achieve green strength or handling strength), and second regions 44 of resin having a low or no amount of light. Fig.11 The pattern is a tile pattern in which first areas 42 of resin are not in contact with each other and are separated by second areas 44 of resin having a low cure or no cure. These areas 42 may include areas of the run-in layer and may include areas of the surface 11 of the device 10. The areas 42 may account for an amount equal to or greater than 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% fill in the layer. Fig.11 The layer or mask 40 in is discontinuous in all directions. In some embodiments, the layer or mask 40 can be used for any of the layers of the device being directly manufactured.

[0085] In some embodiments, a similar pattern as shown in mask 40 can be used to form the interior portion of each layer of the device. In such embodiments, regions 42 of the layer form interior columns extending along the Z direction in the internal structure of the device, such as the sidewalls of an orthodontic aligner.

[0086] Fig.12 An example layer or cure mask 40 of body 16 is shown having a pattern suitable for inhibiting warping of dental device 10 . Fig.12 The pattern includes strips of first regions 42 of resin cured with a high amount of light (such as a dose sufficient for the resin to achieve green strength or handling strength), and strips of second regions 44 of resin having a low or no amount of light. Fig.12The pattern is a stripe pattern. In some examples, the strips of the first region 42 may extend perpendicular to the longest dimension of the body 16 adhered to the build platform 30. For example, if the length of the body is greater than the width, the strips 42 may extend along the width of the body. These regions 42 may include regions of the running-in layer and may include regions of the surface 11 of the device 10. The regions 42 may account for an amount equal to or greater than 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95% fill in the layer. In some embodiments, the layer or mask 40 may be used for any of the layers of the device being directly manufactured.

[0087] In some embodiments, a similar pattern as shown in mask 40 can be used to form the interior portion of each layer of the device. In such embodiments, regions 42 of the layer form interior walls extending in the Z direction in the internal structure of the device, such as the side walls of an orthodontic aligner. The wall can be said to be continuous along the length of the wall in the internal structure of the device, but discontinuous in the direction between the walls.

[0088] Fig.13 An example cross section of a dental device is shown. Fig.13 The dental device includes a tapered platform 46 that reduces the amount of resin that contacts the building platform 30. The tapered platform structure 46 can be Figures 10 to 12 The tapered platform structures 46 may extend through multiple layers. Multiple grooves may extend between multiple platform structures 46. In some examples, the layers may be cured using the techniques previously described to reduce deformation, such as warping. These regions 42 may include regions of the running-in layer and may include regions of the surface 11 of the device 10. These regions 42 may include regions of the running-in layer and may include regions of the surface 11 of the device 10. Reference Fig.16 , depicting an orthodontic aligner 1600. The orthodontic aligner 1600 may include a plurality of tooth receiving cavities 1610. The orthodontic aligner 1600 may be manufactured using additive manufacturing techniques such as those described herein. The additive manufacturing techniques described herein for reducing warpage and stress in manufactured parts are well suited for devices with low aspect ratios, wherein the height along a build direction 1630 (such as a Z axis) is greater than a cross-sectional dimension 1632 of the device in an X–Y plane parallel to the build plate. The aspect ratio may be less than 0.25 (the height is one quarter of the cross-sectional dimension), less than 0.2, less than 0.15, less than 0.1, or less than 0.05. The cross-sectional dimension may be the maximum distance between positions of the device in the XY plane.

[0089] Fig.17 Depicted is a cross-sectional view taken along AA of the tooth receiving cavity 1610. Fig.16 16. A cross section of an orthodontic aligner 1600. The tooth receiving cavity 1610 includes a buccal wall 1620, a lingual wall 1614, and an occlusal wall 1616. Each side wall includes an outwardly facing surface 1620 and an inwardly facing surface 1622. Fig.17 The cross-section depicted in FIG. 1 shows how the internal structure or filler can be formed or cured so that the material reaches green strength. In particular, one or more of the masks discussed above are used to form a tooth receiving cavity structure. For example, Fig.11 4. The mask 40 depicted in FIG. 4. The first region 42 of each layer forms columns 46 of green strength material within the structure of the aligner 1600, while the second region 44 forms portions of uncured or less cured resin between the columns 46. In some embodiments, the columns may intersect with an outer surface of the structure, such as an outward-facing surface 1620 and an inward-facing surface 1622. In some embodiments, one or more of the filling columns 46 may begin at a first end on an outer surface of the aligner and end at a second end on an outer surface of the aligner. In some embodiments, the orthodontic aligner 1600 is formed so that a less cured or uncured resin volume corresponding to the second region 44 remains within the aligner between its outer surfaces. After the outer surfaces 1620, 1622 of the aligner are formed and the first region 42 is cured to green strength, the aligner may be subjected to a secondary curing process, wherein the uncured material or resin corresponding to the region 44 is cured to a final or ultimate strength together with the first region 42.

[0090] Fig.18 Shown along Fig.17 The cross section of aligner 1600 shows a single layer of the aligner in an Annex light plane parallel to the plane of the build platform on which aligner 1600 is formed. Fill pattern 1624 may be similar to Fig.11 The mask 40 shown. The cured or green strength portion of the aligner is represented by the first region 42 and the perimeters 1620 and 1622, which represent the outer or exterior surface of the aligner. In some embodiments, the first region 42 can intersect the perimeters 1620, 1622. For example, the first region 48 intersects the perimeter 1620, such that the first region 48 and the perimeter 1620 are continuous with each other.

[0091] Fig.19 A method 1900 for manufacturing a device described herein is shown. At block 1910, a three-dimensional model of a device, such as an orthodontic device, is sliced ​​into a plurality of layers. The slicing process divides the three-dimensional model into a plurality of two-dimensional layers, each two-dimensional layer representing a portion of the height of the device represented by the three-dimensional model. For example, if the layer height is 10 μm, each layer will represent a 10 μm thick portion of the device.

[0092] At box 1920, a first mask for a first layer of a plurality of layers is determined. The mask may be a two-dimensional planar representation of a cross section of the device at a particular layer height. For a first layer of the model divided into 10 μm layer heights, the first layer may represent a cross-sectional structure of the device at a height between zero and 10 μm. The first mask may include a projected image of a filler and outer perimeter for a first curing operation for a first region of the first layer. At box 1920, a light energy dose and radiation intensity for curing a first region of the device within the first layer may be determined. The light energy dose may be sufficient to cure the resin to its green strength and adhere the resin to the build plate. For subsequent layers, the light energy dose may be sufficient to cure the resin to its green strength and adhere the resin to the previously cured layer.

[0093] At box 1930, a second mask for a first layer of the plurality of layers is determined. The second mask may include a projected image of a filler for a second curing operation of a second region of the first layer. In some embodiments, the second mask may include a perimeter, a first region, and a second region. At box 1940, a light energy dose and a radiation intensity for a second region of the curing device within the first layer may be determined. The light energy dose may not be sufficient to cure the resin to its green strength. In some embodiments, the curing dose provided during exposure of the first mask may not be sufficient to allow the material to reach its green strength, however, upon receiving a second dose according to a second mask (which includes a mask of the first region, the second region, and the perimeter), the first region may be cured to its green strength.

[0094] After completing step 1930, the process may repeat steps 1920 and 1930 for each of the plurality of layers of the three-dimensional model.

[0095] At block 1940, instructions for executing the plurality of layers may be outputted. Outputting the instructions may include storing the instructions or sending them to a manufacturing machine, such as an additive manufacturing machine.

[0096] At block 1950, a first layer of the plurality of layers of the device is cured using a first mask for a first dose. At block 1950, a first layer of the plurality of layers of the device is cured at a second dose using a second mask. Blocks 1950 and 1960 may be repeated for each layer of the plurality of layers of the device.

[0097] At block 1970, a post-processing or secondary curing process may occur. For example, after each layer of the device is formed in blocks 1950 and 1960, the device may be subjected to a secondary curing process by which the resin in the device (including both green strength materials (but not resin) and resins less than green strength) is cured to its final or ultimate strength.

[0098] Reference Fig.14, which shows an example schematic diagram of an additive manufacturing apparatus 100 (such as a 3D printer). The additive manufacturing apparatus 100 includes a print head 102 (such as a projector) and a building platform 104. The additive manufacturing apparatus 100 includes a processor 106, which includes a central processing unit (CPU) 108 and a memory 110. As described herein, the processor 106 can be configured with instructions for directly manufacturing a rectifier. As described herein, the instructions can include instructions for directly manufacturing each of a plurality of layers along a deposition direction to form a precursor rectifier. During the direct manufacturing process, the print head 102 prints each of the plurality of layers, and the spacing distance between the print head 102 and the building platform 104 increases. In some embodiments, the print head can be a projector that projects light according to the mask discussed herein.

[0099] although Fig.14 The additive manufacturing apparatus 100 is shown in a vertical orientation, wherein the print head 102 is located above the building platform 104, but other types of additive manufacturing apparatus are also suitable for use with the disclosed embodiments. For example, the print head 102 can be located below the building platform 104. Typically, the direct manufacturing process forms a single planar layer that is approximately parallel to the building platform 104 at a time. After forming a layer, the print head 102 can be moved away from the building platform 104 and a new layer is formed. Alternatively or in combination, the building platform 104 can be moved away from the print head 102. Each successive layer is built on the previous layer, such as on top of or below the previous layer. Although the additive manufacturing apparatus 100 100 is shown in a vertical orientation, other orientations can be used for one or more components as described herein, such as a horizontal orientation or an inclined orientation.

[0100] Fig.15 A schematic diagram of a method 200 for manufacturing a dental device is shown. At step 202, a direct manufacturing configuration is selected to directly manufacture multiple resin layers to form a body having an upper surface and a substantially planar lower surface. In some examples, at step 204, multiple layers are directly manufactured, wherein each of the multiple layers is cured to have a similar amount of polymer crosslinking. In some examples, at step 206, multiple layers of a first layer having a substantially planar surface and a second layer spaced apart from the first layer are directly manufactured, wherein each of the first layer and the second layer has an amount of polymer crosslinking greater than the amount of polymer crosslinking of multiple inner layers between the first layer and the second layer. In some examples, at step 208, multiple layers are directly manufactured, wherein the body has an increased dimension along a direction of potential warping (e.g., along a Z direction as described herein) to reduce deformation. In some examples, at step 210, multiple layers are directly manufactured, wherein the lower surface includes a platform pattern defining a plurality of grooves in a substantially planar surface.

[0101] although Fig.15A method of manufacturing a dental device according to some embodiments is shown, but a person skilled in the art will recognize many modifications and variations. For example, the steps may be performed in a different order, some steps may be repeated, and some steps may be removed.

[0102] As mentioned above, the computing devices and systems described and / or illustrated herein broadly represent any type or form of computing device or system capable of executing computer-readable instructions (such as those contained within the modules described herein). In their most basic configuration, these computing devices can each include at least one memory device and at least one physical processor.

[0103] As used herein, the term "memory" or "memory device" generally refers to any type or form of volatile or non-volatile storage device or medium capable of storing data and / or computer-readable instructions. In one example, a memory device can store, load, and / or maintain one or more of the modules described herein. Examples of memory devices include, but are not limited to, random access memory (RAM), read-only memory (ROM), flash memory, hard disk drive (HDD), solid-state drive (SSD), optical drive, cache, variations or combinations of one or more of the above, or any other suitable storage memory.

[0104] In addition, as used herein, the term "processor" or "physical processor" generally refers to a hardware-implemented processing unit of any type or form that can interpret and / or execute computer-readable instructions. In one example, a physical processor can access and / or modify one or more modules stored in the above-mentioned memory device. Examples of physical processors include, but are not limited to, a microprocessor, a microcontroller, a central processing unit (CPU), a field programmable gate array (FPGA) application specific integrated circuit (ASIC) implementing a soft-core processor, a portion of one or more of them, a variation or combination of one or more of them, or any other suitable physical processor.

[0105] Although shown as separate elements, the method steps described and / or illustrated herein may represent portions of a single application. Additionally, in some embodiments, one or more of these steps may represent or correspond to one or more software applications or programs that, when executed by a computing device, may cause the computing device to perform one or more tasks, such as method steps.

[0106] In addition, one or more of the devices described herein can convert data, physical devices, and / or representations of physical devices from one form to another. For example, one or more of the devices described herein can receive image data of a sample to be converted, convert the image data, output the result of the conversion to determine a 3D process, use the result of the conversion to perform the 3D process, and store the result of the conversion to produce an output image of the sample. Additionally or alternatively, one or more of the modules described herein can convert a processor, volatile memory, non-volatile memory, and / or any other part of a physical computing device from one form of computing device to another form of computing device by executing on a computing device, storing data on a computing device, and / or otherwise interacting with a computing device.

[0107] As used herein, the term "computer-readable medium" generally refers to any form of device, carrier, or medium that can store or carry computer-readable instructions. Examples of computer-readable media include, but are not limited to, transmission-type media (such as carrier waves) and non-transitory media (such as magnetic storage media (e.g., hard drives, tape drives, and floppy disks), optical storage media (e.g., compact disks (CDs), digital video disks (DVDs), and Blu-ray disks), electronic storage media (e.g., solid-state drives and flash memory media), and other distribution systems).

[0108] Those of ordinary skill in the art will recognize that any process or method disclosed herein may be modified in many ways. The process parameters and order of steps described and / or illustrated herein are given as examples only and may be varied as desired. For example, although the steps illustrated and / or described herein may be illustrated or discussed in a particular order, the steps do not necessarily need to be performed in the order illustrated or discussed.

[0109] The various exemplary methods described and / or shown herein may also omit one or more steps described or shown herein, or include additional steps in addition to those disclosed. In addition, the steps of any method disclosed herein may be combined with any one or more steps of any other method disclosed herein.

[0110] Unless otherwise indicated, the terms "connected to" and "coupled to" (and their derivatives) used in the specification and claims should be interpreted as allowing both direct and indirect (i.e., via other elements or components) connections. In addition, the terms "a" or "an" used in the specification and claims should be interpreted to mean "at least one". Finally, for ease of use, the terms "including" and "having" (and their derivatives) used in the specification and claims are interchangeable with the word "comprising" and shall have the same meaning as the word "including".

[0111] A processor as disclosed herein may be configured with instructions to perform any one or more steps of any method as disclosed herein.

[0112] As used herein, the term "or" is used inclusively to refer to items in alternatives and combinations.

[0113] As used herein, characters such as numbers refer to similar elements.

[0114] This disclosure also includes the following numbered items.

[0115] Item 1. An oral device comprising: a plurality of layers of cured photopolymer material, the plurality of layers forming a body, the body comprising an upper surface and a substantially planar lower surface; wherein at least a first layer of the plurality of layers is cured to a first strength at a first dose, and at least a second layer of the plurality of layers is cured to a second strength at a second dose to inhibit warping of the body.

[0116] Item 2. The oral device according to Item 1, further comprising at least one support and at least one attachment for a tooth and at least one support, wherein the at least one support connects the at least one attachment to the body.

[0117] Item 3. The oral device of any one of Items 1 and 2, wherein each layer of the plurality of layers has been cured to have a similar amount of polymer cross-linking.

[0118] Item 4. The oral device of Item 3, wherein each of the plurality of layers has an amount of polymer cross-links that is within a range of about 90% and 110% of an average amount of polymer cross-links of the plurality of layers.

[0119] Item 5. The oral device of Item 3, wherein an initial build layer of the plurality of layers has an amount of polymer cross-linking suitable for adhesion to a build platform.

[0120] Item 6. An oral device according to any one of Items 1 to 5, wherein the initial layer of the substantially planar surface and the second layer spaced apart from the first layer each have an amount of polymer crosslinking greater than the amount of polymer crosslinking of the inner multiple layers between the first layer and the second layer.

[0121] Item 7. An oral device according to Item 6, wherein the initial layer and the second layer have similar amounts of polymer cross-linking.

[0122] Item 8. The oral device of Item 6, wherein each of the inner plurality of layers has a similar amount of polymer cross-linking.

[0123] Item 9. An oral device according to Item 8, wherein each layer of the internal multiple layers has an amount of polymer crosslinks between 90% and 110% of the average amount of polymer crosslinks of the internal multiple layers, and wherein the first layer and the second layer each have an amount of polymer crosslinks between 90% and 110% of the average amount of polymer crosslinks of the first layer and the second layer, and wherein the average value of the internal multiple layers is at least about 10% less than the average value of the first layer and the second layer.

[0124] Item 10. The oral device of any one of Items 1 to 9, wherein the body has a width, a length, and a thickness, wherein the thickness of the body is at least 0.25 times the length.

[0125] Item 11. The oral device of any one of Items 1 to 10, wherein the body has a width, a thickness, and a length, wherein the thickness of the body is no more than .25 times the length.

[0126] Item 12. The oral device of any one of Items 1 to 11, wherein the lower surface comprises a pattern of platforms defining a plurality of grooves in a substantially planar surface.

[0127] Item 13. An oral device according to Item 12, wherein the pattern includes one or more of a checkerboard pattern, a tile pattern, or a stripe pattern.

[0128] Item 14. The oral device of Item 12, wherein the platform covers between twenty-five percent and seventy-five percent of the surface area defined by the outer perimeter of the platform pattern.

[0129] Item 15. The oral device of Item 12, wherein the platform comprises a taper that widens from a face of the platform toward the upper surface.

[0130] Item 16. An oral device according to any one of Items 1 to 15, wherein the lower surface has a pattern comprising areas of cured photopolymer material having a higher amount of polymer cross-links and areas of cured photopolymer material having a lower amount of polymer cross-links.

[0131] Item 17. An oral device according to any one of Items 1 to 16, wherein the body includes an attachment for a tooth.

[0132] Item 18. An oral device according to Item 17, wherein the attachment for the tooth includes a substantially flat surface for engaging the tooth, and the substantially flat surface includes a substantially planar surface.

[0133] Item 19. The oral device of any one of Items 1 to 18, wherein the body comprises an elongated structure operable to position an attachment for a tooth.

[0134] Item 20. The oral device of Item 19, wherein the body has a length and a width, wherein the length is at least four times the width.

[0135] Item 21. The oral device of Item 19, further comprising a registration structure for positioning the oral device and a support structure for coupling the registration structure to the body.

[0136] Item 22. An oral device according to Item 21, wherein the alignment structure and the attachment are connected to opposite sides of the oral device.

[0137] Item 23. The oral device of Item 21, wherein the at least one layer for inhibiting warping extends through two or more of the body, the support structure, or the support member.

[0138] Item 24. The oral device of Item 21, wherein the solidified layer extends through the attachment and the registration structure.

[0139] Item 25. A method for manufacturing an oral device, comprising: directly manufacturing multiple resin layers to form a body including an upper surface and a substantially planar lower surface; and wherein the planar lower surface is directly manufactured to a build platform, and wherein at least a first layer of the multiple layers is cured to a first strength with a first dose, and at least a second layer of the multiple layers is cured to a second strength with a second dose to inhibit warping of the body.

[0140] Item 26. A method according to Item 25, wherein the oral device also includes at least one accessory and at least one support member connecting the accessory to the body, wherein the method also includes directly manufacturing a plurality of support layers for forming the support member and a plurality of accessory layers for forming the accessory.

[0141] Item 27. The method of any one of Items 25 to 26, further comprising manufacturing each of the plurality of layers directly to have a similar amount of polymer cross-linking.

[0142] Item 28. The method according to any one of Items 25 to 27 further includes directly manufacturing a first layer at the surface of the plane and directly manufacturing a second layer at the upper surface, wherein the amount of polymer crosslinking in the first layer and the second layer is greater than the amount of polymer crosslinking in the internal multiple layers between the first layer and the second layer.

[0143] Item 29. The method according to any one of Items 25 to 28, further comprising directly manufacturing the first layer and the second layer to have the same amount of polymer cross-linking.

[0144] Item 30. The method of Items 25 to 29, further comprising directly manufacturing each of the inner plurality of layers to have the same amount of polymer cross-linking.

[0145] Item 31. The method of any one of Items 25 to 30, wherein the body has a width, a length, and a thickness, wherein the thickness of the body is at least 0.25 times the length.

[0146] Item 32. The method according to any one of Items 25 to 31, further comprising directly manufacturing the lower surface to have a terrace pattern.

[0147] Item 33. The method of Item 32, wherein the pattern comprises one or more of a checkerboard pattern, a tile pattern, or a stripe pattern.

[0148] Item 34. The method of any one of Items 25 to 33, further comprising directly manufacturing the platform to have an area between twenty-five percent and seventy-five percent of an area defined by a perimeter of the plurality of platforms.

[0149] Item 35. The method according to Item 32 further includes directly manufacturing the platform to have a tapered shape that widens from the face of the platform toward the upper surface.

[0150] Item 36. The method of Item 32, wherein the lower surface has a pattern comprising resin regions having a high amount of polymer cross-links and resin regions having a lower amount of polymer cross-links.

[0151] Item 37. The method of Item 36, wherein the pattern comprises one or more of a checkerboard pattern, a tile pattern, or a stripe pattern.

[0152] Item 38. A method for manufacturing a device, the method comprising: cutting a 3D model of the device into multiple layers; determining a first mask for a first area of ​​a first layer among the multiple layers; determining a second mask for a second area of ​​the first layer among the multiple layers; and outputting instructions for forming multiple layers.

[0153] Item 39. The method of Item 38, wherein determining the first mask comprises determining a first curing dose.

[0154] Item 40. The method of Item 39, wherein determining a second mask comprises determining a second cure dose that is less than the first cure dose.

[0155] Item 41. The method of Item 40, wherein the first curing amount is sufficient to cure the resin of the first region to its green strength.

[0156] Item 42. The method of Item 40, wherein the second curing amount is insufficient to cure the resin of the second region to its green strength.

[0157] Item 43. A method according to Item 42, wherein the first region includes a perimeter of the first layer of the plurality of layers, and the second region includes the first region and the perimeter, and wherein the first dose is insufficient to cure the resin of the first region to its green strength, and the second dose is sufficient to cure the resin of the first region to its green strength but insufficient to cure the second region to its green strength.

[0158] Item 44. The method of any one of Items 38 to 43, further comprising: determining a first mask and a second mask for each of the remaining plurality of layers.

[0159] Item 45. A method for manufacturing a dental brace, the method comprising: receiving instructions for curing multiple layers to manufacture the dental brace; curing a first area of ​​resin for a first layer of the multiple layers with a first mask; and curing a second area of ​​resin for the first layer of the multiple layers with a second mask.

[0160] Item 46. The method of Item 45, wherein the first region is cured with a first dose of light energy.

[0161] Item 47. The method of Item 46, wherein the second region is cured with a second dose of light energy.

[0162] Item 48. The method of Item 46, wherein the first curing amount is sufficient to cure the resin of the first region to its green strength.

[0163] Item 49. The method of Item 48, wherein the second curing amount is insufficient to cure the resin of the second region to its green strength.

[0164] Item 50. A method according to Item 46, wherein the first region includes a perimeter of the first layer of the plurality of layers, and the second region includes the first region and the perimeter, and wherein the first dose is insufficient to cure the resin of the first region to its green strength, and the second dose is sufficient to cure the resin of the first region to its green strength but insufficient to cure the second region to its green strength.

[0165] Item 51. The method of Item 45, further comprising: determining a first mask and a second mask for each of the remaining plurality of layers.

[0166] The embodiments of the present disclosure have been shown and described as set forth herein, and are provided by way of example only. Without departing from the scope of the present disclosure, one of ordinary skill in the art will recognize many modifications, changes, variations, and substitutions. Without departing from the scope of the present disclosure and the invention disclosed herein, several substitutions and combinations of the embodiments disclosed herein may be utilized. Therefore, the scope of the presently disclosed invention shall be limited only by the scope of the appended claims and their equivalents.

Claims

1. An oral device, include: a plurality of layers of cured photopolymer material forming a body including an upper surface and a substantially planar lower surface and further comprising a plurality of registration structures shaped to engage a patient retention surface extending between the substantially planar lower surface and the upper surface, and a plurality of second resin layers to form a plurality of platforms extending from a build plate to the substantially planar lower surface, the plurality of platforms extending from the build plate each forming a taper widening from the build plate toward the substantially planar lower surface, wherein grooves separate the plurality of platforms from one another; wherein at least a first layer of the plurality of layers is cured to a first strength and at least a second layer of the plurality of layers is cured to a second strength at a third curing dose to suppress warping of the body, wherein the first layer of the plurality of layers is cured to the first strength using a first mask with a first cure dose, the first mask comprising an outer perimeter of the oral device and a first fill region having a fill pattern, and a second mask is used for a first layer of the plurality of resin layers on a build plate with a second cure dose to compensate for warping, the second mask comprising a second fill region, and wherein the first layer of the plurality of layers is a substantially flat lower surface.

2. An oral device, include: a plurality of layers of cured photopolymer material forming a body including an upper surface and a substantially planar lower surface and further comprising a plurality of registration structures shaped to engage a patient retention surface extending between the substantially planar lower surface and the upper surface, and a plurality of second resin layers to form a plurality of platforms extending from a build plate to the substantially planar lower surface, the plurality of platforms extending from the build plate each forming a taper widening from the build plate toward the substantially planar lower surface, wherein grooves separate the plurality of platforms from one another; wherein at least a first layer of the plurality of layers is cured to a first strength with a first dose, and at least a second layer of the plurality of layers is cured to a second strength with a second dose to suppress warping of the body, and At least one support and at least one attachment for a tooth, wherein the at least one support couples the at least one attachment to the body.

3. The oral device according to claim 1, in, Each of the plurality of layers has been cured to have a similar amount of polymer cross-linking.

4. The oral device according to claim 3, in, Each of the plurality of layers has an amount of polymer crosslinks within a range of 90% and 110% of an average amount of polymer crosslinks of the plurality of layers.

5. The oral device according to claim 3, in, An initial build layer of the plurality of layers has an amount of polymer cross-linking suitable for adhesion to the build platform.

6. The oral device according to claim 1, in, An initial layer of the substantially planar surface and a second layer spaced apart from the first layer each have an amount of polymer crosslinks greater than an amount of polymer crosslinks of an inner plurality of layers between the first layer and the second layer.

7. The oral device according to claim 6, in, The initial layer and the second layer have similar amounts of polymer crosslinking.

8. The oral device according to claim 6, in, Each of the inner plurality of layers has a similar amount of polymer cross-linking.

9. The oral device according to claim 8, in, Each of the inner multiple layers has a polymer cross-linking amount between 90% and 110% of the average polymer cross-linking amount of the inner multiple layers, and wherein the first layer and the second layer each have a polymer cross-linking amount between 90% and 110% of the average polymer cross-linking amount of the first layer and the second layer, and wherein the average value of the inner multiple layers is at least 10% less than the average value of the first layer and the second layer.

10. The oral device according to claim 1, in, The body has a width, a length, and a thickness, wherein the thickness of the body is at least 0.25 times the length.

11. The oral device according to claim 1, in, The body has a width, a thickness and a length, wherein the thickness of the body is no more than 0.25 times the length.

12. The oral device of claim 1, in, The pattern includes one or more of a checkerboard pattern, a tile pattern or a stripe pattern.

13. The oral device of claim 1, in, The platforms cover between twenty-five percent and seventy-five percent of the surface area defined by the outer perimeter of the platform pattern.

14. The oral device of claim 1, in, The lower surface has a pattern including regions of the cured photopolymer material having a higher amount of polymer cross-links and regions of the cured photopolymer material having a lower amount of polymer cross-links.

15. An oral device, include: a plurality of layers of cured photopolymer material forming a body including an upper surface and a substantially planar lower surface and further comprising a plurality of registration structures shaped to engage a patient retention surface extending between the substantially planar lower surface and the upper surface, and a plurality of second resin layers to form a plurality of platforms extending from a build plate to the substantially planar lower surface, the plurality of platforms extending from the build plate each forming a taper widening from the build plate toward the substantially planar lower surface, wherein grooves separate the plurality of platforms from one another; wherein at least a first layer of the plurality of layers is cured to a first strength with a first dose, and at least a second layer of the plurality of layers is cured to a second strength with a second dose to suppress warping of the body, and Wherein, the body includes accessories for teeth.

16. The oral device of claim 15, in, The attachment for a tooth includes a substantially flat surface for engaging a tooth, and the substantially flat surface includes a substantially planar surface.

17. The oral device of claim 15, in, The body includes an elongated structure operable to position an attachment for a tooth.

18. The oral device of claim 17, in, The body has a length and a width, wherein the length is at least four times the width.

19. The oral device of claim 17, in, The registration structure and the attachment are coupled to opposite sides of the oral device.

20. The oral device of claim 17, in, At least one layer for inhibiting warping extends through two or more of the body, support structure or support.

21. The oral device of claim 17, in, A solidified layer extends through the attachment and the registration structure.

22. A method of manufacturing an oral device, include: Directly manufacturing an oral device comprising a plurality of resin layers to form a body comprising an upper surface and a substantially planar lower surface by the following steps; as well as forming a first layer of a multi-layer resin on a build plate with a first curing dosage using a first mask, the first mask including an outer perimeter of an oral placement device and a first fill region having a fill pattern, the first layer of the multi-layer forming the substantially planar lower surface, determining a second curing dose and a second mask for the first layer of the multi-layer resin on the build plate to compensate for warpage, the second mask including a second fill region, The lower surface is directly manufactured to have a terrace pattern, wherein the terraces are directly manufactured to have an area between 25 percent and 75 percent of an area defined by the perimeter of the plurality of terraces, curing the first of the plurality of layers on the build plate with a second cure dose using a second mask; and wherein at least a first layer of the plurality of layers is cured to a first strength with a first curing dose and a second curing dose, wherein at least a second layer of the plurality of layers is cured to a second strength to inhibit warping of the body, and Wherein the body includes a plurality of registration structures shaped to engage a patient retention surface extending between the substantially planar lower surface and the upper surface.

23. The method according to claim 22, in, The oral device further comprises at least one attachment and at least one support coupling the attachment to the body, wherein the method further comprises directly manufacturing a plurality of support layers for forming the support and a plurality of attachment layers for forming the attachment.

24. The method of claim 22, further comprising directly manufacturing each of the plurality of layers so that each of the plurality of layers has a polymer cross-linking amount within a range of 90% and 110% of an average polymer cross-linking amount of the plurality of layers.

25. The method according to claim 22 also includes directly manufacturing a first layer at the surface of the plane and directly manufacturing a second layer at the upper surface, wherein the amount of polymer cross-linking in the first layer and the second layer is greater than the amount of polymer cross-linking in the internal multiple layers between the first layer and the second layer.

26. The method of claim 25, further comprising directly manufacturing the first layer and the second layer to have the same amount of polymer cross-linking.

27. The method of claim 25, further comprising directly manufacturing each of the inner plurality of layers to have the same amount of polymer cross-linking.

28. The method according to claim 22, in, The body has a width, a length, and a thickness, wherein the thickness of the body is at least 0.25 times the length.

29. The method according to claim 22, in, The pattern includes one or more of a checkerboard pattern, a tile pattern or a stripe pattern.

30. The method of claim 22, further comprising directly manufacturing the platform to have a tapered shape that widens from a face of the platform toward the upper surface.

31. The method according to claim 22, in, The lower surface has a pattern including a resin region having a high polymer cross-linking amount and a resin region having a lower polymer cross-linking amount.

32. The method according to claim 31, in, The pattern includes one or more of a checkerboard pattern, a tile pattern or a stripe pattern.

33. A method of manufacturing a device, the method include: cutting the 3D model of the device into a plurality of layers, the plurality of layers forming a body including an upper surface and a substantially planar lower surface, and further comprising a plurality of registration structures shaped to engage a patient retention surface extending between the substantially planar lower surface and the upper surface, and a plurality of second resin layers to form a plurality of platforms extending from a build plate to the substantially planar lower surface, the plurality of platforms extending from the build plate each forming a taper widening from the build plate toward the substantially planar lower surface, wherein grooves separate the plurality of platforms from each other; determining a first mask for a first area of ​​a first layer of the plurality of layers and a first curing dosage for curing the first layer, the first mask including an outer perimeter of the oral placement device and a first filling area having a filling pattern; determining a second mask for a second region of the first layer of the plurality of layers and a second curing dose for the second mask, the second mask including a second filling region; and Outputs instructions for forming multiple layers.

34. The method according to claim 33, in, Determining the first mask includes determining a first curing dose.

35. The method according to claim 34, in, Determining a second mask includes determining a second curing dose that is less than the first curing dose.

36. The method according to claim 35, in, The first curing amount is sufficient to cure the resin in the first region to its green strength.

37. The method according to claim 35, in, The second curing amount is insufficient to cure the resin in the second region to its green strength.

38. The method according to claim 37, in, The first region includes a perimeter of the first layer of the plurality of layers, and the second region includes the first region and the perimeter, and wherein the first curing dose is insufficient to cure the resin of the first region to its green strength, and the second curing dose is sufficient to cure the resin of the first region to its green strength but insufficient to cure the second region to its green strength.

39. The method according to claim 33, further comprising: include: A first mask and a second mask are determined for each of the remaining plurality of layers.

40. A method of manufacturing a dental brace, the method include: receiving instructions for curing a plurality of layers to manufacture the dental appliance, the plurality of layers forming a body including an upper surface and a substantially planar lower surface and further comprising a plurality of registration structures shaped to engage a patient retention surface extending between the substantially planar lower surface and the upper surface, and a plurality of second resin layers to form a plurality of platforms extending from a build plate to the substantially planar lower surface, the plurality of platforms extending from the build plate each forming a taper widening from the build plate toward the substantially planar lower surface, wherein grooves separate the plurality of platforms from one another; curing a first region of a resin for a first layer of the plurality of layers with a first curing dose using a first mask, the first mask including an outer perimeter of the oral placement device and a first fill region having a fill pattern; as well as A second region of resin for a first layer of the plurality of layers is cured on the build plate with a second mask at a second cure dose and a second mask for a first layer of the plurality of layers of resin to compensate for warpage, the second mask including a second fill region.

41. The method according to claim 40, in, The first region is cured with a first dose of light energy.

42. The method according to claim 41, in, The second region is cured with a second dose of light energy.

43. The method according to claim 41, in, The first curing amount is sufficient to cure the resin of the first region to its green strength.

44. The method according to claim 43, in, The second curing amount is insufficient to cure the resin of the second region to its green strength.

45. The method according to claim 41, in, The first region includes a perimeter of the first layer of the plurality of layers, and the second region includes the first region and the perimeter, and wherein the first dose is insufficient to cure the resin of the first region to its green strength, and the second cure dose is sufficient to cure the resin of the first region to its green strength but insufficient to cure the second region to its green strength.

46. ​​The method according to claim 40, further comprising: include: A first mask and a second mask are determined for each of the remaining plurality of layers.

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