Orthodontic placement device, method for manufacturing orthodontic placement device, oral device, and method for manufacturing oral device

Abstract

Orthodontic placement devices and methods of making the same, and oral devices and methods of making the same are disclosed wherein the method of making an oral device includes cutting a 3D model of the device into a plurality of layers, the layers including substantially planar lower and upper surfaces and including a plurality of registration structures, the registration structure is shaped to engage a patient dentition surface extending between the substantially planar lower surface and the upper surface; determining a first mask for a first region of a first layer of the plurality of layers and a first amount of curing agent for curing the first layer, the first mask comprising an outer perimeter of the device and a first fill region; determining a second mask for a second region of the first layer of the plurality of layers and a second curing agent amount for the second mask, the second mask including a second filling region; and outputting an instruction for forming the plurality of layers.

Description

[0001] This application is a divisional application of the application whose applicant is "Allain Technologies Co., Ltd.", whose application date is July 29, 2020, whose application number is 202080055736.2, and whose invention name is "System and method for additive manufacturing of dental devices using photopolymer resin". Background Art

[0002] 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 can have less than ideal strength and, in at least some cases, can warp.

[0003] 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 components 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.

[0004] In at least some cases, varying the amount of light energy between layers can cause warping of the component. Delivering different amounts of light energy to different layers typically results in different amounts of crosslinking within the layers. Photopolymers can shrink during curing, and the amount of shrinkage can be related to the amount of crosslinking. Different amounts of crosslinking and curing can produce different levels of shrinkage within the component. Different amounts of shrinkage can lead to the development of internal stresses within the component, which can manifest as warping or curling.

[0005] This effect can be further exacerbated for directly manufactured parts, where the lateral dimension of the part along the build platform area is greater than the part thickness along the build direction. Furthermore, structures positioned away from the build platform may experience movement when the base structure warps. To mitigate these effects, parts can be suspended away from the build platform and secured there by thin posts connecting the part to the platform. However, such posts can take additional time to manufacture and may need to be removed in subsequent manufacturing steps, adding time and complexity to the manufacturing process.

[0006] In view of the foregoing, there exists 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 would overcome at least some of the foregoing limitations of previous methods. Summary of the Invention

[0007] 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 appliances that reduce warping when manufactured directly onto 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 the removal of standoffs.

[0008] According to a first embodiment of the present invention, there is provided a method for manufacturing a device, the method comprising:

[0009] slicing the 3D model of the device into a plurality of layers, the layers comprising a substantially planar lower surface and an upper surface, and comprising a plurality of registration structures shaped to engage a surface of the patient's dentition extending between the substantially planar lower surface and the upper surface;

[0010] determining a first mask for a first area of ​​a first layer of the plurality of layers and a first cure dose for curing the first layer, the first mask including an outer perimeter of the device and a first fill area;

[0011] determining a second mask for a second region of the first layer among the plurality of layers and a second curing dose for the second mask, the second mask including a second filling region; and

[0012] Instructions for forming the plurality of layers are output.

[0013] According to a second aspect of the present application, there is provided a method for manufacturing a dental brace, the method comprising:

[0014] receiving instructions for curing a plurality of layers to produce the dental appliance, the plurality of layers comprising a substantially planar lower surface and an upper surface and comprising a plurality of registration structures shaped to engage a patient's dentition surface extending between the substantially planar lower surface and the upper surface;

[0015] curing a first region of a resin for a first layer of the plurality of layers with a first cure dose using a first mask, the first mask including an outer perimeter of the dental appliance and a first fill region; and

[0016] A second region of resin for a first layer of the plurality of layers is cured on a build plate of a manufacturing machine with a second mask at a second cure dose and a second mask for the first layer of the plurality of layers of resin to compensate for warpage, the second mask including a second fill region.

[0017] According to a third embodiment of the present application, there is provided a method for manufacturing an orthodontic placement device, comprising:

[0018] Directly manufacturing an orthodontic placement device, the orthodontic placement device comprising a first plurality of layers of resin and a second plurality of layers of resin to form a body comprising a substantially planar lower surface, an upper surface, and a body comprising a plurality of registration structures shaped to engage a patient's dentition surface extending between the substantially planar lower surface and the upper surface, the direct manufacturing of the orthodontic placement device being achieved by the following steps:

[0019] forming a first layer of the first multi-layer resin with a first curing dose using a first mask, the first mask including an outer perimeter for forming an outer perimeter of the orthodontic placement device and a first fill region having a fill pattern;

[0020] determining a second curing dose and a second mask for a first layer in the first multi-layer resin to compensate for warpage, the second mask including a second fill region;

[0021] curing a first layer of the first multi-layer resin with a second curing dose using a second mask, wherein the first curing dose and the second curing dose cure at least the first layer of the first multi-layer resin to a first strength, and wherein at least a second layer of the first multi-layer resin layer is cured to a second strength to suppress warping of the body;

[0022] The second multi-layer resin is formed.

[0023] According to a fourth aspect of the present application, a method for manufacturing an orthodontic placement device is provided, the method comprising:

[0024] receiving a 3D model of the orthodontic placement device;

[0025] modifying the 3D model of the orthodontic placement device to include one or more stress relief structures configured to relieve stresses generated during the manufacturing process of the physical orthodontic placement device;

[0026] slicing the 3D model of the orthodontic placement device into a plurality of layers, wherein the orthodontic placement device is sliced ​​into a first plurality of layers and a second plurality of layers to form a body comprising a substantially planar lower surface, an upper surface, and a plurality of registration structures shaped to engage a patient's dentition surface extending between the substantially planar lower surface and the upper surface;

[0027] determining a first mask and a first cure dose for a first region of the first plurality of layers;

[0028] determining a second mask and a first cure dose for a second region of a first layer in the first plurality of layers; and

[0029] Instructions for forming the plurality of layers are output.

[0030] According to a fifth aspect of the present application, an oral device is provided, comprising:

[0031] a plurality of layers comprising a substantially planar lower surface and an upper surface and comprising a plurality of registration structures shaped to engage a patient's dentition surface extending between the substantially planar lower surface and the upper surface;

[0032] wherein the outer perimeter of the oral device and a first fill region of a first layer of the plurality of layers are cured with a first mask and a first cure dose, and wherein a second fill region of the first layer of the plurality of layers is cured with a second mask and a second cure dose.

[0033] According to a sixth embodiment of the present application, an orthodontic placement device is provided, comprising:

[0034] first and second layers of resin to form a body including a substantially planar lower surface, an upper surface, and a plurality of registration structures shaped to engage a patient's dentition surface extending between the substantially planar lower surface and the upper surface,

[0035] wherein the first layer of the first multi-layer resin is cured to a first strength using a first curing dose using a first mask, the first mask including an outer perimeter of the orthodontic placement device and a first filling area having a filling pattern,

[0036] wherein the second filling region of the first layer in the first multi-layer resin is cured with a second mask and a second dose to compensate for warpage, and

[0037] At least the second layer of the first plurality of resin layers is cured to a second strength to suppress warping of the body.

[0038] According to a seventh embodiment of the present application, an orthodontic placement device is provided, comprising:

[0039] a body having one or more stress relief structures for relieving stresses generated during the manufacture of a physical orthodontic placement device, and a first plurality of layers and a second plurality of layers, the plurality of layers including a substantially planar lower surface, an upper surface, and a plurality of registration structures shaped to engage a patient's dentition surface extending between the substantially planar lower surface and the upper surface;

[0040] curing a first region of a first layer of the first plurality of layers with a first dose using a first mask;

[0041] A second region of a first layer of the first plurality of layers is cured using a second mask and a second dosage.

[0042] 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.

[0043] 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.

[0044] In some embodiments, each layer in the plurality of layers has been cured to have a similar amount of polymer crosslinks. In some embodiments, each layer in the plurality of layers has a polymer crosslink amount that is within a range of about 90% and 110% of an average polymer crosslink amount of the plurality of layers. In some embodiments, each layer in the plurality of layers has a similar amount of polymer crosslinks suitable for adhesion to a build platform.

[0045] 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 in an inner plurality of layers between the first and second layers. The first and second layers can have similar amounts of polymer crosslinks, and each of the inner plurality of layers can 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 in the inner plurality of layers, and the first and second layers each have an amount of polymer crosslinks that is between 90% and 110% of the average amount of polymer crosslinks in the first and second layers, wherein the average of the inner plurality of layers is at least about 10% less than the average of the first and second layers.

[0046] 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.

[0047] 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 striped 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.

[0048] In some embodiments, the lower surface has a pattern comprising regions of resin having a higher amount of polymer cross-links and regions of resin having a lower amount of polymer cross-links.

[0049] 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.

[0050] 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 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.

[0051] 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.

[0052] In some embodiments, the oral device comprises at least one accessory and at least one support coupling the accessory to a body, and the method further comprises directly manufacturing a plurality of support layers forming the support and a plurality of accessory layers forming the accessory.

[0053] In some embodiments, the method further comprises fabricating each of the plurality of layers to have the same amount of polymer crosslinks. In some embodiments, the method further comprises fabricating a first layer directly at the surface of the planar surface and a second layer directly at the upper surface, the first and second layers having a greater amount of polymer crosslinks than an inner plurality of layers between the first and second layers. In some embodiments, the method further comprises fabricating the first and second layers to have a similar amount of polymer crosslinks. In some embodiments, the method further comprises fabricating each of the inner plurality of layers to have a similar amount of polymer crosslinks.

[0054] 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.

[0055] In some embodiments, the method further comprises directly manufacturing the lower surface to have a platform pattern. The pattern may comprise one or more of a checkerboard pattern, a tile pattern, or a stripe 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 cone that widens from the surface 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 stripe pattern.

[0056] Incorporated by Reference

[0057] All patents, applications, and publications mentioned and identified herein are incorporated by reference in their entirety and should be considered fully incorporated by reference even if mentioned elsewhere in this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] 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:

[0059] Figure 1 An example of a dental apparatus for positioning an orthodontic attachment according to some embodiments is shown;

[0060] Figure 2 Attached to a tooth according to some embodiments is shown. Figure 1 Examples of dental devices;

[0061] 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;

[0062] Figure 4 An example dental apparatus for positioning an orthodontic attachment on a set of teeth is shown according to some embodiments;

[0063] 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;

[0064] Figure 6 shows a dental apparatus according to some embodiments;

[0065] Figure 7 shows example layers of a directly manufactured dental device according to some embodiments;

[0066] Figure 8 shows example layers of a directly manufactured dental device according to some embodiments;

[0067] Figure 9 shows example layers of a directly manufactured dental device according to some embodiments;

[0068] Figure 10 shows example layers of a directly manufactured dental device according to some embodiments;

[0069] Figure 11 shows example layers of a directly manufactured dental device according to some embodiments;

[0070] Figure 12 shows example layers of a directly manufactured dental device according to some embodiments;

[0071] Figure 13 shows example layers of a directly manufactured dental device according to some embodiments;

[0072] Figure 14 shows a schematic diagram of a direct manufacturing machine according to some embodiments;

[0073] Figure 15 shows a schematic diagram of a method for manufacturing a dental device according to some embodiments;

[0074] Figure 16 shows a dental apparatus according to some embodiments;

[0075] Figure 17 According to some embodiments Figure 16 Cross-section of a dental device;

[0076] Figure 18 According to some embodiments Figure 16 a cross-section of a dental device; and

[0077] Figure 19 A method of additively manufacturing a dental device according to some embodiments is shown. DETAILED DESCRIPTION

[0078] 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 by way of example only and should not be construed as limiting the scope of the invention disclosed herein. The methods, apparatus 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 coupling to teeth, night guards, functional braces and directly manufactured aligner thermoforming molds. The methods, apparatus 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 apparatus 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 a brace comprising a variety of different materials.

[0079] 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) tank photopolymerization (e.g., stereolithography), in which an object is constructed layer by layer from a tank 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 a build material (e.g., a powder-based material) and a binding material (e.g., a 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 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 of the aligners described herein. In some embodiments, stereolithography includes the 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 to build up 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 to form continuous layers of the object geometry.

[0080] In some embodiments, the direct manufacturing methods provided herein build object geometries in a layer-by-layer manner, wherein continuous layers are formed in discrete building steps. Alternatively or in combination, direct manufacturing methods that allow for the continuous construction of object geometries 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 aligners herein are manufactured using "continuous liquid interphase printing," in which an object is continuously built from a container of photopolymerizable resin by forming a gradient of partially cured resin between the build 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 in order to form a polymerization gradient. Continuous liquid interphase printing can achieve manufacturing speeds that are about 25 times to about 100 times faster than other direct manufacturing methods, and can achieve speeds that are about 1,000 times faster by incorporating a cooling system. Continuous liquid interphase printing is described in U.S. Patent Publication Nos. 2015 / 0097315, 2015 / 0097316, and 2015 / 0102532, the disclosures of each of which are incorporated herein by reference in their entirety.

[0081] As another example, a continuous direct manufacturing method can achieve continuous construction of the object geometry by continuously moving the build platform (e.g., in the vertical or Z direction) during the irradiation phase, so that the hardening depth of the irradiated photopolymer is controlled by the movement speed. Thus, continuous polymerization of the material on the build 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.

[0082] In another example, a continuous direct manufacturing method can involve extruding a composite material composed 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.

[0083] In yet another example, a continuous direct manufacturing method utilizes a "spiral lithography" approach, in which a liquid photopolymer is cured by focused radiation while the build platform continuously rotates and rises. Thus, the 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.

[0084] The direct manufacturing method provided herein is compatible with various materials, including but not limited to one or more of the following: polymer matrices, polyesters, copolyesters, polycarbonates, thermoplastic polyurethanes, polypropylene, polyethylene, polypropylene and polyethylene copolymers, acrylic acid, cyclic block copolymers, polyetheretherketones, polyamides, polyethylene terephthalate, polybutylene terephthalate, polyetherimides, polyethersulfones, polytrimethylene terephthalate, styrene block copolymers (SBC), silicone rubber, elastic alloys, thermoplastic elastomers (TPE), thermoplastic vulcanizates (TPV) elastomers, polyurethane elastomers, block copolymer elastomers, polyolefin blended elastomers, thermoplastic copolyester elastomers, thermoplastic polyamide elastomers or combinations thereof. The material for direct manufacturing can be provided in an uncured form (e.g., as a liquid, resin, powder, etc.) and can be cured (e.g., by photopolymerization, light curing, 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 portion of the brace.

[0085] 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.

[0086] In some embodiments, the relatively elastic portion of the orthodontic brace can be formed by direct manufacturing using one or more of the following materials: styrene block copolymers (SBC), silicone rubber, elastomeric alloys, thermoplastic elastomers (TPE), thermoplastic vulcanizate (TPV) elastomers, polyurethane elastomers, block copolymer elastomers, polyolefin blend elastomers, thermoplastic copolyester elastomers and / or thermoplastic polyamide elastomers.

[0087] 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, multi-material direct manufacturing methods involve simultaneously forming an object from multiple materials 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 to manufacture an object from multiple different materials. Such methods are described in U.S. Patent No. 6,749,414, the disclosure of which is incorporated herein by reference in its entirety. Alternatively, or in combination, multi-material direct manufacturing methods 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 of the direct manufacturing methods described herein, followed by a second portion of the object being formed from a second material according to the methods described herein, and so on, until the entire object has been formed. The relative arrangement of the first and second portions can be varied as desired; for example, the first portion can be partially or fully 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.

[0088] Direct manufacturing can provide various advantages over other manufacturing methods. For example, compared to indirect manufacturing, direct manufacturing allows orthodontic appliances to be produced without utilizing any molds or templates to shape the appliances, thereby reducing the number of manufacturing steps involved and improving the resolution and accuracy of the final appliance geometry. In addition, direct manufacturing allows precise control over the three-dimensional geometry of the appliance, such as appliance thickness. Complex structures and / or auxiliary components can be formed integrally with the appliance shell as a single piece 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 appliance geometries that are difficult to create using alternative manufacturing techniques, such as appliances with very small or delicate features, complex geometries, undercuts, interproximal structures, shells with variable thickness, and / or internal structures (e.g., to increase 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.

[0089] The direct manufacturing techniques described herein can be used to produce braces having substantially isotropic material properties (e.g., substantially the same or similar strength in all directions). In some embodiments, the direct manufacturing methods herein allow for 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 rate than other manufacturing techniques. In some embodiments, the direct manufacturing methods herein allow for the production of orthodontic braces in a time interval of less than or equal to about 1 hour, about 30 minutes, about 25 minutes, about 20 minutes, about 15 minutes, about 10 minutes, about 5 minutes, about 4 minutes, about 3 minutes, about 2 minutes, about 1 minute, or about 30 seconds. Such manufacturing speeds allow for rapid "chairside" production of custom braces, such as during routine appointments or checkups.

[0090] In some embodiments, the direct manufacturing methods described herein implement process control over various machine parameters of the direct manufacturing system or apparatus to ensure that the resulting aligner is manufactured with high precision. Such precision can be beneficial in ensuring that the desired force system is accurately transmitted to the teeth to effectively induce tooth movement. Process control can be implemented to account for process variability caused by multiple sources, such as material properties, machine parameters, environmental variables, and / or post-processing parameters.

[0091] Material properties can vary according to the process variables during the properties of the raw materials, the purity of the raw materials and / or the mixing of the raw materials. In many embodiments, the resin or other materials used for direct manufacturing should be manufactured with strict process control to ensure that the change of 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) is 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 variability of the reduction 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.

[0092] Machine parameters may include curing parameters. For digital light processing (DLP)-based curing systems, curing parameters may include power, curing time, and / or grayscale of the complete image. For laser-based curing systems, curing parameters may include power, speed, beam size, beam shape, and / or beam power distribution. For printing systems, curing parameters may include material droplet size, viscosity, and / or curing power. As part of process control on the manufacturing machine, these machine parameters can be monitored and adjusted periodically (e.g., some parameters every 1-x layers, some parameters after each build). Process control can 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, grayscale can be measured and calibrated before, during, and / or at the end of each build and / or at predetermined intervals (e.g., every nth build, once an hour, once a day, once a week, etc.). Additionally, material properties and / or light characteristics can be provided to the manufacturing machine, and the machine process control module can 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.

[0093] 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.

[0094] 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. Additionally, the physical properties of the brace may be altered by modifying the post-processing parameters. Adjusting the post-processing machine parameters may provide another way to compensate for variability in material properties and / or machine properties.

[0095] Although specific reference is made to dental components (such as orthodontic devices and molds for orthodontic devices), the methods and apparatus disclosed herein will have 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 aerospace, automotive, particularly for component manufacturing, and the like.

[0096] Figure 1An exemplary dental device 10 is shown for positioning an attachment 12 on a patient's teeth 13. 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 directly manufactured with at least one layer to inhibit warping. The dental device 10 can include a body 16, an attachment 12, and one or more supports 14. The dental device 10 can be sized and shaped to be positioned on multiple teeth of a patient, either in the upper or lower jaw. The body 16 can include any number of suitable structures for placement on one or more teeth of a patient, such as a thin-shell polymer aligner including multiple tooth-receiving cavities sized and shaped to receive the patient's teeth. The dental device 10 can be coupled to the attachment 12 via one or more supports 14, and the body 16 can 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 can be formed as a single component. For example, as described herein, the dental device 10 and the attachment 12 can 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 polymer shell dental appliances. For example, the attachment can be coupled to a polymer shell dental appliance commercially available from Align Technology, Inc. Use together with treatment.

[0097] The described device and method are suitable for the direct production of a dental device 10 with the attachment 12 as a single component, the direct production of a dental device 10 with the attachment 12 as a separate component, or the direct production of an attachment 12 .

[0098] Figure 2 An attachment 12 is shown secured to a patient's tooth 13. The attachment 12 can serve as an anchor during orthodontic procedures and can enhance the performance of orthodontic devices during tooth movement. In some examples, the attachment 12 can be bonded to the tooth using an adhesive. The surface of the attachment 12 can include a smooth surface for bonding to the tooth, or a textured surface 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.

[0099] Figure 3An exemplary dental device 10 is shown for placement on a patient's teeth. 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-engaging 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.

[0100] Dental device 10 includes a body 16; a plurality of attachments 12; a plurality of supports 14 coupling attachments 12 to body 16; a plurality of registration structures 18; and a plurality of support structures 20 coupling registration structures 18 to body 16. Body 16 may include one or more elongated structures 17. Body 16 may include a single U-shaped member including one or more elongated structures 17, or it may include multiple elongated structures 17 that may be joined together. The position of each of the plurality of attachments on each tooth can be determined by a treating professional using planning software, and device 10 can be manufactured directly based on the positions determined using the treatment planning software.

[0101] 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, with the alignment structure 18 contacting 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 tooth. Once the attachment 12 is coupled to the tooth, 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, leaving the attachment 12 coupled to the patient's teeth in a desired position (e.g., a predetermined position).

[0102] In some embodiments, the elongated body 16 includes one or more structures for reducing deformation, as described herein, to properly position the attachment 12 on the patient's tooth. For example, the one or more elongated structures 17 of the body 16 can include one or more structures for reducing deformation, as described herein, to properly position the attachment 12 on the patient's tooth. While 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 structures 17 can include a layer for inhibiting warping of the surface 11, such as a counter layer having a similar amount of crosslinking and exposure to light as the running-in layer of the surface 11.

[0103] Figure 4 and Figure 5 The 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. A 3D digital model 25 can be used as a basis for generating instructions for directly manufacturing one or more components of the dental device 10, and in some embodiments, the entire dental device 10. As described herein, one or more components of the device 10 can be directly manufactured to inhibit warpage, and as described herein, the device 10 can include at least one component directly manufactured with at least one layer to inhibit warpage. 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, structures for reducing warpage can be identified on the 3D model. Surface 11 can be located in a directly manufactured layer on a surface or device opposite the tooth-engaging side of the device, or between the tooth-engaging side of the device and the tooth-engaging side or surface of the device, and 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 can be constructed accordingly. As described herein, the at least one layer for inhibiting warpage 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 fabrication of the dental device 10. For example, one or more of the elongated structures 17 may be configured to be directly fabricated with features for inhibiting warping, as described herein.

[0104] Dental device 10 includes a body 16 , a plurality of attachments 12 , a plurality of supports 14 coupling attachments 12 to body 16 , a registration structure 18 , and a support structure 20 coupling registration structure 18 to body 16 .

[0105] Figure 4 A model 25 of the patient's teeth and a vestibular view of the dental apparatus 10 are shown. Figure 4As shown, the dental device 10 is sized and shaped 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.

[0106] 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.

[0107] 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 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, such that elements of the body 16 engage through 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, can be slightly less than the width of the patient's teeth, such that elastic deformation of the support 14 or support structure 20 serves to assemble 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.

[0108] Figure 7 A cross-section of an example dental device 10 is shown, illustrating 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 can include one or more of the supports 14, the support structure 20, or one or more elongated structures 17. Although a single structure 34 is shown, the dental device can include, for example, multiple structures 34 extending from the body 32. In some embodiments, the dental device can be free of support structures. In some embodiments, the dental device 10 can be an orthodontic aligner, and the layer 26 can be a layer forming the orthodontic aligner, including the sidewalls of one or more tooth-receiving cavities.

[0109] Dental device 10 includes a plurality of directly fabricated layers 26. A first layer 28 is fabricated directly on a build platform 30, and each successive layer is fabricated directly on each previous layer. If build platform 30 is referred to as the 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.

[0110] exist Figure 7 In an example, first layer 28 may comprise surface 11 of a dental device. In an orthodontic aligner, first layer 28 may be the occlusal or incisor surface of the 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 can 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 first layer 28 to build platform 30. The dose may be delivered at a rate of 0.1 W / cm². 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 build 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 layers may be cured with an energy dose sufficient to cure the resin to its green strength. In some embodiments, the layers may be cured at a dose between 95% and 105% or between 90% and 110% of the green strength dose. In some embodiments, the layers may be cured at 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 their green strength, such as at least 5% less or 10% less.

[0111] Figure 8A cross-section of an example dental device 10 is shown, illustrating example layers for suppressing warping of one or more components of the device, such as body 16. In this example, first layer 28 is directly manufactured using an amount of light energy selected to be a minimum amount higher than that used to adhere first layer 28 to build platform 30. Subsequent layers are cured with an amount of light sufficient to adhere the layer to first layer 28, but with a consistent amount of light as layers are added. For example, first layer 28 can be cured using a dose of light provided at a rate of 0.15 W / cm^2 sufficient to adhere the first layer to the build platform, and subsequent layers can be cured using a dose less than the dose of the first layer provided at a rate of 0.05 W / 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, this method can be combined with methods for suppressing deformation.

[0112] Figure 9 A cross section of an example dental device 10 is shown illustrating example layers for inhibiting warping of the body 16. Figure 9 In the example shown, first layer 28 is cured using an amount of light energy (dose) sufficient to adhere first layer 28 to build platform 30. Another layer 36 can be directly manufactured similarly to first layer 28 to offset the effects of the 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 using an amount of light similar to that of layer 28. Layer 28 can include an outer layer 36 of body 16 opposite first layer 28. Layer 36 can be cured using an amount of light energy similar to that of first layer 28. In some examples, for example, a layer between first layer 28 and outer layer 36 can be manufactured using 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.

[0113] In some examples, each layer between first layer 28 and outer layer 36 can be produced using a similar amount of light energy. In other examples, the amount of light energy used for each layer can vary, but have a symmetrical relationship about centerline 38 of body 16. For example, after first layer 28, each subsequent layer can be cured using a lower amount of light energy than the previous one, up to the intermediate layer or centerline 38 between first layer 28 and layer 36. Each subsequent layer can be cured using a similar amount of light energy as the layer opposite the intermediate layer or centerline 38. For example, if first layer 28 is cured using a first dose amount, the second layer can be cured using a dose of light energy that is 20% lower than the first dose. The third intermediate layer can be cured using a dose 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 using a dose that is 20% lower than the first dose. Finally, outer layer 36 opposite first layer 28 relative to centerline 38 can be cured using the first dose amount 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.

[0114] Although this example lists only five layers, one of ordinary skill in the art will recognize that a symmetrical pattern 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 successively lower amount of energy, and each successive layer between the center line or middle layer and the outer layer is cured with a greater 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 energy 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 energy than each subsequent layer.

[0115] Figure 10An example of a layer 40 of body 16 having a pattern for inhibiting warping is shown. Layer 40 is viewed perpendicular to build platform 30 and may represent a view of a single layer. In some embodiments, layer 40 is shown as a curing mask for a layer. In some examples, the pattern shown can be used to create a single layer, or in other examples, the pattern can be repeated for multiple layers to form a platform. Layer 40 includes a first region 42 of resin cured using a first dose or amount of light suitable for adhesion to build platform 30 or a previous layer, and a second region 44 of resin cured using a second dose or lower amount of light or remaining uncured. In some embodiments, the mask depicts regions 42 where light energy is provided to cure the layer, and regions 44 where less light energy or no light energy is provided to cure the layer. First region 42 may include surface 11 of dental device 10. In some examples, instead of the resin being cured using a low dose of light, the resin may be left uncured so that no resin remains in the second region when the part is removed from build platform 30. Figure 10 The pattern is such that first regions 42 and second regions 44 alternate in a checkerboard pattern. The pattern can cover the entire surface of the body that contacts the build platform 30, or in some examples, the pattern can cover limited areas. For example, these areas can be located on the first layer. In some embodiments, each layer formed by the object can be formed using a checkerboard or alternating mask, such as Figure 10 , for the internal structure of an object. In some embodiments, the fill percentage between first region 42 and 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 layers where the checkerboard pattern of the layer comprises less than 50% of the first region, the first region may not be connected across the layer and the layer is discontinuous.

[0116] In some embodiments, the layer can include a third region cured at a third dose. Similar to the first and second layers, the third region can 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.

[0117] Figure 11 An example layer or cure mask 40 of the body 16 is shown having a pattern suitable for inhibiting warping of the dental device 10 . Figure 11 The pattern includes first regions 42 of resin cured with a high dose 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 dose of light. Figure 11 The pattern is a tile pattern in which first regions 42 of resin are not in contact with each other and are separated by second regions 44 of resin having a low or no cure. These regions 42 may include regions of the run-in layer and may include regions of the surface 11 of the device 10. The regions 42 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% fill in the layer. Figure 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.

[0118] 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 internal columns extending along the Z direction in the internal structure of the device, such as the sidewalls of an orthodontic aligner.

[0119] Figure 12 An example layer or cure mask 40 of the body 16 is shown having a pattern suitable for inhibiting warping of the dental device 10 . Figure 12 The pattern includes strips of first regions 42 of resin cured with a high dose 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 dose of light. Figure 12The pattern is a stripe pattern. In some examples, the strips of first region 42 may extend perpendicular to the longest dimension of body 16 adhered to build platform 30. For example, if the length of the body is greater than the width, 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 surface 11 of device 10. 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, layer or mask 40 may be used for any of the layers of a directly manufactured device.

[0120] 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 within the internal structure of the device, such as the sidewalls of an orthodontic aligner. The walls can be said to be continuous along the length of the wall within the internal structure of the device, but discontinuous in the direction between the walls.

[0121] Figure 13 An example cross section of a dental device is shown. Figure 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 previously described techniques 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 Figure 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 the 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 being one quarter 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.

[0122] Figure 17 Depicts a section taken along AA of the tooth receiving cavity 1610. Figure 16 16. A cross-section of an orthodontic aligner 1600 is shown. The tooth receiving cavity 1610 includes a buccal sidewall 1620, a lingual sidewall 1614, and an occlusal wall 1616. Each sidewall includes an outwardly facing surface 1620 and an inwardly facing surface 1622. Figure 17 The cross-section depicted in FIG shows how an internal structure or filler may 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, Figure 11 4. The mask 40 depicted in FIG. 4. The first regions 42 of each layer form columns 46 of green strength material within the structure of the aligner 1600, while the second regions 44 form 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 filler 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 such that a volume of less cured or uncured resin corresponding to the second regions 44 remains within the aligner between its outer surfaces. After the outer surfaces 1620, 1622 of the aligner are formed and the first regions 42 are cured to green strength, the aligner may undergo a secondary cure process in which the uncured material or resin corresponding to the regions 44 is cured together with the first regions 42 to a final or ultimate strength.

[0123] Figure 18 Shown along Figure 17 The cross section of aligner 1600 shows a single layer of the aligner in the Annex light plane parallel to the plane of the build platform on which aligner 1600 is formed. Fill pattern 1624 can be similar to Figure 11 The mask 40 is 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 surfaces 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.

[0124] Figure 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.

[0125] At block 1920, a first mask is determined for a first layer of the plurality of layers. 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 an outer perimeter for a first curing operation for a first region of the first layer. At block 1920, a light energy dose and radiation intensity may be determined for curing a first region of the device within the first layer. 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.

[0126] At box 1930, a second mask is determined for a first layer of the plurality of layers. The second mask may include a projected image of a filler for a second curing operation in a second area of ​​the first layer. In some embodiments, the second mask may include a perimeter, a first area, and a second area. At box 1940, a light energy dose and a radiation intensity for a second area of ​​the curing device located 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 for the material to reach its green strength, however, upon receiving a second dose according to the second mask (which includes a mask of the first area, the second area, and the perimeter), the first area may be cured to its green strength.

[0127] After completing step 1930 , the process may repeat steps 1920 and 1930 for each of the plurality of layers of the three-dimensional model.

[0128] Instructions for executing the plurality of layers may be output at block 1940. Outputting the instructions may include storing the instructions or sending them to a manufacturing machine, such as an additive manufacturing machine.

[0129] 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, the first layer of the plurality of layers of the device is cured using a second mask for a second dose. Blocks 1950 and 1960 may be repeated for each layer of the plurality of layers of the device.

[0130] A post-processing or secondary curing process may occur at block 1970. For example, after forming each layer of the device in blocks 1950 and 1960, the device may undergo 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.

[0131] Reference Figure 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 build 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 the aligner. 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 aligner. During the direct manufacturing process, the print head 102 prints each of the plurality of layers, and the separation distance between the print head 102 and the build platform 104 increases. In some embodiments, the print head can be a projector that projects light according to the mask discussed herein.

[0132] although Figure 14 Additive manufacturing apparatus 100 is shown in a vertical orientation with print head 102 positioned above build platform 104, but other types of additive manufacturing apparatus are also suitable for use with the disclosed embodiments. For example, print head 102 can be positioned below build platform 104. Typically, a direct manufacturing process forms a single planar layer at a time that is generally parallel to build platform 104. After forming a layer, print head 102 can be moved away from build platform 104 and a new layer can be formed. Alternatively, or in combination, build platform 104 can be moved away from print head 102. Each successive layer is built upon, e.g., on top of or below, the previous layer. Although additive manufacturing apparatus 100 is shown in a vertical orientation, other orientations may be used for one or more components as described herein, such as a horizontal orientation or an inclined orientation.

[0133] Figure 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 a plurality of resin layers to form a body having an upper surface and a substantially planar lower surface. In some examples, at step 204, the plurality of layers are directly manufactured, wherein each of the plurality of layers is cured to have a similar amount of polymer crosslinking. In some examples, at step 206, a plurality of layers are directly manufactured, including a first layer having a substantially planar surface and a second layer spaced apart from the first layer, wherein each of the first and second layers has a greater amount of polymer crosslinking than a plurality of inner layers between the first and second layers. In some examples, at step 208, the plurality of 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, the plurality of layers are directly manufactured, wherein the lower surface includes a platform pattern having a plurality of grooves defined in a substantially planar surface.

[0134] although Figure 15A method of manufacturing a dental device according to some embodiments is shown, but those 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.

[0135] 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.

[0136] 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 disk drive, cache, variations or combinations of one or more of the foregoing, or any other suitable storage memory.

[0137] In addition, as used herein, the term "processor" or "physical processor" generally refers to any type or form of hardware-implemented processing unit capable of interpreting and / or executing computer-readable instructions. In one example, the 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, microprocessors, microcontrollers, central processing units (CPUs), field programmable gate arrays (FPGAs) implementing soft-core processors, application-specific integrated circuits (ASICs), portions of one or more of them, variations or combinations of one or more of them, or any other suitable physical processor.

[0138] 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.

[0139] 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 results of the conversion to determine a 3D process, use the results of the conversion to perform the 3D process, and store the results 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 portion of a physical computing device from one form of computing device to another form of computing device by executing on the computing device, storing data on the computing device, and / or otherwise interacting with the computing device.

[0140] As used herein, the term "computer-readable medium" generally refers to any form of device, carrier, or medium capable of storing or carrying 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).

[0141] Those skilled in the art will recognize that any process or method disclosed herein can be modified in many ways. The process parameters and step sequences described and / or illustrated herein are provided as examples only and may be varied as desired. For example, although the steps shown and / or described herein may be shown or discussed in a particular order, the steps do not necessarily need to be performed in the order shown or discussed.

[0142] The various exemplary methods described and / or illustrated herein may also omit one or more steps described or illustrated 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.

[0143] 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. Additionally, 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 should have the same meaning as the word "comprising."

[0144] A processor as disclosed herein may be configured with instructions to perform any one or more steps of any method as disclosed herein.

[0145] As used herein, the term "or" is used inclusively to refer to items in alternatives and combinations.

[0146] As used herein, characters such as numbers refer to similar elements.

[0147] This disclosure also includes the following numbered items.

[0148] 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.

[0149] Item 2. The oral device of 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 couples the at least one attachment to the body.

[0150] 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.

[0151] Item 4. The oral device of Item 3, wherein each of the plurality of layers has an amount of polymer cross-links within a range of about 90% and 110% of an average amount of polymer cross-links of the plurality of layers.

[0152] 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.

[0153] 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 that is greater than the amount of polymer crosslinking of the inner plurality of layers between the first layer and the second layer.

[0154] Item 7. The oral device of Item 6, wherein the initial layer and the second layer have similar amounts of polymer cross-linking.

[0155] Item 8. The oral device of Item 6, wherein each layer of the inner plurality of layers has a similar amount of polymer cross-linking.

[0156] Item 9. An oral device according to Item 8, wherein each layer of the inner plurality of layers has an amount of polymer crosslinks between 90% and 110% of the average amount of polymer crosslinks of the inner plurality of 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 inner plurality of layers is at least about 10% less than the average value of the first layer and the second layer.

[0157] 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.

[0158] 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 0.25 times the length.

[0159] 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.

[0160] Item 13. The oral device of Item 12, wherein the pattern comprises one or more of a checkerboard pattern, a tile pattern, or a striped pattern.

[0161] 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.

[0162] 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.

[0163] 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-linking and areas of cured photopolymer material having a lower amount of polymer cross-linking.

[0164] Item 17. The oral device of any one of Items 1 to 16, wherein the body comprises an attachment for a tooth.

[0165] Item 18. The oral device of Item 17, wherein the attachment for the tooth comprises a substantially flat surface for engaging the tooth, and the substantially flat surface comprises a substantially planar surface.

[0166] 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.

[0167] 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.

[0168] Item 21. The oral device of Item 19, further comprising a registration structure for positioning the oral device and a support structure coupling the registration structure to the body.

[0169] Item 22. The oral device of Item 21, wherein the registration structure and the attachment are coupled to opposite sides of the oral device.

[0170] 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.

[0171] Item 24. The oral device of Item 21, wherein the solidified layer extends through the attachment and the registration structure.

[0172] Item 25. A method of manufacturing an oral device, comprising: directly manufacturing a plurality of resin layers to form a body comprising an upper surface and a substantially planar lower surface; and wherein the planar lower surface is manufactured directly to a build platform, and 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 inhibit warping of the body.

[0173] Item 26. A method according to Item 25, wherein the oral device further comprises at least one accessory and at least one support member connecting the accessory to the body, wherein the method further comprises directly manufacturing a plurality of support layers for forming the support member and a plurality of accessory layers for forming the accessory.

[0174] Item 27. The method of any one of Items 25 to 26, further comprising directly manufacturing each of the plurality of layers to have a similar amount of polymer cross-linking.

[0175] 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 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.

[0176] Item 29. The method of 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.

[0177] Item 30. The method of Items 25 to 29, further comprising directly manufacturing each layer of the inner plurality of layers to have the same amount of polymer cross-linking.

[0178] 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.

[0179] Item 32. The method according to any one of Items 25 to 31, further comprising directly manufacturing the lower surface with the terrace pattern.

[0180] 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.

[0181] 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 the perimeter of the plurality of platforms.

[0182] Item 35. The method according to Item 32, further comprising directly manufacturing the platform to have a tapered shape that widens from the face of the platform toward the upper surface.

[0183] Item 36. The method of Item 32, wherein the lower surface has a pattern comprising regions of resin having a high amount of polymer cross-links and regions of resin having a lower amount of polymer cross-links.

[0184] 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.

[0185] 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 the multiple layers.

[0186] Item 39. The method of Item 38, wherein determining the first mask comprises determining a first curing dose.

[0187] 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.

[0188] Item 41. The method of Item 40, wherein the first curing dose is sufficient to cure the resin of the first region to its green strength.

[0189] 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.

[0190] Item 43. The method of Item 42, wherein the first region comprises a perimeter of the first layer of the plurality of layers, and the second region comprises 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.

[0191] 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.

[0192] 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.

[0193] Item 46. The method of Item 45, wherein the first region is cured with a first dose of light energy.

[0194] Item 47. The method of Item 46, wherein the second region is cured with a second dose of light energy.

[0195] Item 48. The method of Item 46, wherein the first curing dose is sufficient to cure the resin of the first region to its green strength.

[0196] Item 49. The method of Item 48, wherein the second curing agent dosage is insufficient to cure the resin of the second region to its green strength.

[0197] Item 50. The method of Item 46, wherein the first region comprises a perimeter of the first layer of the plurality of layers, and the second region comprises 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.

[0198] 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.

[0199] 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, those skilled 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. A method for manufacturing a device, the method comprising: slicing the 3D model of the device into a plurality of layers, the layers comprising a substantially planar lower surface and an upper surface, and comprising a plurality of registration structures shaped to engage a surface of the patient's dentition extending between the substantially planar lower surface and the upper surface; determining a first mask for a first area of ​​a first layer of the plurality of layers and a first cure dose for curing the first layer, the first mask including an outer perimeter of the device and a first fill area; determining a second mask for a second region of the first layer among the plurality of layers and a second curing dose for the second mask, the second mask including a second filling region; and Instructions for forming the plurality of layers are output.

2. A method for manufacturing a dental brace, the method comprising: receiving instructions for curing a plurality of layers to produce the dental appliance, the plurality of layers comprising a substantially planar lower surface and an upper surface and comprising a plurality of registration structures shaped to engage a patient's dentition surface extending between the substantially planar lower surface and the upper surface; curing a first region of a resin for a first layer of the plurality of layers with a first cure dosage using a first mask, the first mask including an outer perimeter of the dental appliance and a first fill region; as well as A second region of resin for a first layer of the plurality of layers is cured on a build plate of a manufacturing machine with a second mask at a second cure dose and a second mask for the first layer of the plurality of layers of resin to compensate for warpage, the second mask including a second fill region.

3. A method for manufacturing an orthodontic placement device, comprising: Directly manufacturing an orthodontic placement device, the orthodontic placement device comprising a first plurality of layers of resin and a second plurality of layers of resin to form a body comprising a substantially planar lower surface, an upper surface, and a body comprising a plurality of registration structures shaped to engage a patient's dentition surface extending between the substantially planar lower surface and the upper surface, the direct manufacturing of the orthodontic placement device being achieved by the following steps: forming a first layer of the first multi-layer resin with a first curing dose using a first mask, the first mask including an outer perimeter for forming an outer perimeter of the orthodontic placement device and a first fill region having a fill pattern; determining a second curing dose and a second mask for a first layer in the first multi-layer resin to compensate for warpage, the second mask including a second fill region; curing a first layer of the first multi-layer resin with a second curing dose using a second mask, wherein the first curing dose and the second curing dose cure at least the first layer of the first multi-layer resin to a first strength, and wherein at least a second layer of the first multi-layer resin layer is cured to a second strength to suppress warping of the body; The second multi-layer resin is formed.

4. A method for manufacturing an orthodontic placement device, the method comprising: receiving a 3D model of the orthodontic placement device; modifying the 3D model of the orthodontic placement device to include one or more stress relief structures configured to relieve stresses generated during the manufacturing process of the physical orthodontic placement device; slicing the 3D model of the orthodontic placement device into a plurality of layers, wherein the orthodontic placement device is sliced ​​into a first plurality of layers and a second plurality of layers to form a body comprising a substantially planar lower surface, an upper surface, and a plurality of registration structures shaped to engage a patient's dentition surface extending between the substantially planar lower surface and the upper surface; determining a first mask and a first cure dose for a first region of the first plurality of layers; determining a second mask and a first cure dose for a second region of a first layer in the first plurality of layers; as well as Instructions for forming the plurality of layers are output.

5. An oral device comprising: a plurality of layers comprising a substantially planar lower surface and an upper surface and comprising a plurality of registration structures shaped to engage a patient's dentition surface extending between the substantially planar lower surface and the upper surface; wherein the outer perimeter of the oral device and a first fill region of a first layer of the plurality of layers are cured with a first mask and a first cure dose, and wherein a second fill region of the first layer of the plurality of layers is cured with a second mask and a second cure dose.

6. An orthodontic placement device comprising: first and second layers of resin to form a body including a substantially planar lower surface, an upper surface, and a plurality of registration structures shaped to engage a patient's dentition surface extending between the substantially planar lower surface and the upper surface, wherein the first layer of the first multi-layer resin is cured to a first strength using a first curing dose using a first mask, the first mask including an outer perimeter of the orthodontic placement device and a first filling area having a filling pattern, wherein the second filling region of the first layer in the first multi-layer resin is cured with a second mask and a second dose to compensate for warpage, and At least the second layer of the first plurality of resin layers is cured to a second strength to suppress warping of the body.

7. An orthodontic placement device comprising: a body having one or more stress relief structures for relieving stresses generated during the manufacture of a physical orthodontic placement device, and a first plurality of layers and a second plurality of layers, the plurality of layers including a substantially planar lower surface, an upper surface, and a plurality of registration structures shaped to engage a patient's dentition surface extending between the substantially planar lower surface and the upper surface; curing a first region of a first layer of the first plurality of layers with a first dose using a first mask; A second region of a first layer of the first plurality of layers is cured using a second mask and a second dosage.

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