Orthosis with an elastic layer

Abstract

Provided are improved orthodontic appliances and related systems and methods. In one aspect, an orthodontic appliance can include a housing having a plurality of cavities shaped to receive a patient's teeth. The housing can include an outer layer and an inner layer having a lower stiffness than the outer layer. A discontinuity can be formed in the outer layer.

Description

[0001] This application is a divisional application of the patent application No. 202010403214.9, titled "Orthosis with Elastic Layer", filed on January 30, 2015.

[0002] Cross - Reference

[0003] This application claims the benefit of U.S. Provisional Application No. 62 / 015,170, filed on June 20, 2014, the entire content of which is incorporated herein by reference. Technical Field

[0004] This application relates to an orthodontic technique, and particularly to an orthodontic orthosis, an orthodontic system, and a method of creating an orthodontic orthosis. Background Art

[0005] To correct malocclusions and / or improve aesthetics, the orthodontic process typically involves repositioning a patient's teeth into a desired alignment. To achieve these goals, an orthodontic orthosis such as a dental brace, retainer, shell aligner, etc. can be applied to the patient's teeth by an orthodontic practitioner. The orthosis is configured to apply forces to one or more teeth in order to produce a desired tooth movement effect. To progressively reposition the teeth into the desired alignment, the practitioner can periodically adjust the application of the forces (e.g., by replacing the orthosis or using a different type of orthosis).

[0006] However, in some cases, current orthodontic orthoses may not effectively generate the forces required to achieve the desired tooth repositioning or may not provide sufficient control over the forces applied to the teeth. Existing orthodontic methods may often employ a single orthosis shell with homogeneous and / or continuous material properties, which provides sub - optimal movement and comfort. In addition, the rigidity of some existing orthoses may impede the ability of the orthosis to attach to the patient's teeth and may increase patient discomfort. Summary of the Invention

[0007] Improved orthodontic orthoses, as well as related systems and methods, are provided. The orthodontic orthosis can include a shell having an outer layer and an inner layer, the outer layer having a greater stiffness than the inner layer. A discontinuity can be formed in the outer layer. When placed on the patient's teeth, the interaction of the inner layer with the discontinuity can apply a force to the underlying teeth to initiate one or more desired tooth movements. The orthoses described herein can provide enhanced control over the forces applied to the teeth, thereby enabling an improved orthodontic treatment process.

[0008] Accordingly, in one aspect, an orthodontic appliance can include a housing having a plurality of cavities shaped to receive a patient's teeth. The housing can include an outer layer and an inner layer, the inner layer having a lower stiffness than the outer layer. A discontinuity can be formed in the outer layer.

[0009] Other objects and features of the present invention will become apparent by reading the specification, claims, and drawings.

[0010] Incorporation by reference

[0011] All publications, patents, and patent applications mentioned in this specification are incorporated herein by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The novel features of the invention are particularly set forth in the appended claims. A better understanding of the features and advantages of the invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings in which:

[0013] Figure 1A Illustrates a tooth repositioning appliance according to multiple embodiments.

[0014] Figure 1B Illustrates a tooth repositioning system according to multiple embodiments.

[0015] Figure 2 Illustrates an orthodontic treatment method using multiple appliances according to multiple embodiments.

[0016] Figure 3A Illustrates a portion of a layered orthodontic appliance according to multiple embodiments.

[0017] Figures 3B to 3I Illustrates a discontinuity formed in the outer layer of a layered orthodontic appliance according to multiple embodiments.

[0018] Figure 4A Illustrates a layered orthodontic appliance having a discontinuity according to multiple embodiments.

[0019] Figure 4B Illustrates an appliance according to multiple embodiments when placed on a patient's teeth Figure 4A of.

[0020] Figure 5A Illustrates a layered orthodontic appliance having a discontinuity according to multiple embodiments.

[0021] Figure 5B Illustrates an appliance according to multiple embodiments when placed on a patient's teeth Figure 5A of.

[0022] Figure 6 illustrates a method for manufacturing an orthodontic appliance according to multiple embodiments.

[0023] Figure 7 illustrates a method for digitally planning orthodontic treatment according to multiple embodiments.

[0024] Figure 8 is a simplified block diagram of a data processing system according to multiple embodiments. Detailed Description

[0025] A better understanding of the features and advantageous effects of the present disclosure will be obtained by referring to the following detailed description that sets forth illustrative embodiments in which the principles of the embodiments of the present disclosure and their accompanying drawings are utilized.

[0026] Although the detailed description contains many details, these details should not be construed as limiting the scope of the present disclosure, but merely as illustrating different examples and aspects of the present disclosure. It should be understood that the scope of the present disclosure includes other embodiments not detailed above. Various other modifications, changes, and variations obvious to those skilled in the art can be made in the details of the layout, operation, and methods, systems, and devices of the present disclosure provided herein without departing from the spirit and scope of the invention described herein.

[0027] As used herein, A and / or B includes more than one of A or B, and combinations thereof, such as A and B.

[0028] To reposition more than one tooth, maintain the current position of more than one tooth, or a suitable combination thereof, the orthodontic appliances and related systems and methods described herein can be employed as part of an orthodontic treatment process. The orthodontic appliance can include an outer layer and an inner layer. The outer layer can be formed of a relatively rigid material, while the inner layer can be formed of a relatively elastic material such that the outer layer is harder than the inner layer. While maintaining the integrity of the inner layer, one or more discontinuities can be formed in the outer layer. The geometry and configuration of the discontinuities can be selected such that when the appliance is worn by a patient, the discontinuities interact with the elastic inner layer to generate forces suitable for repositioning more than one tooth of the patient. In multiple embodiments, the inner layer resists deformation, deflection, and / or displacement of the discontinuities such that forces can be applied to more than one tooth. The material properties (e.g., stiffness) of the appliance described herein can vary via the discontinuities and / or the elastic inner layer, thereby imparting different forces to different teeth of the patient's dental arch and, in some cases, imparting more precisely applied or delivered forces to the teeth while reducing patient discomfort. A variation (varying) can refer to a change in the corresponding material property (e.g., a difference in the value presented in the appliance) that is greater than 10% of the highest value of the corresponding material property presented in the appliance, greater than 25% of that highest value, or greater than 50% of the highest value. Additionally, the techniques described herein can be used to adjust the local compliance of the appliance, thereby improving appliance fit and reducing patient discomfort.

[0029] Thus, in one aspect, an orthodontic appliance can include a housing having a plurality of cavities shaped to receive a patient's teeth. The housing can include an outer layer and an inner layer having a lower stiffness than the outer layer. Discontinuities can be formed in the outer layer. In multiple embodiments, the outer layer has a modulus of elasticity in the range from about 10,000 psi to about 700,000 psi, and the inner layer has a modulus of elasticity in the range from about 100 psi to about 8,000 psi. In alternative embodiments, the inner layer has a modulus of elasticity in the range from about 100 psi to about 50,000 psi.

[0030] The design of the discontinuities can vary as desired to direct appropriate tooth movement. For example, the discontinuities can include incisions formed in the outer layer. The incisions can at least partially extend around a protrusion formed in the outer layer. In some cases, the incisions can be closed incisions, such as an incision around a region of the housing. The incisions can extend from the buccal surface of the outer layer to the lingual surface of the outer layer. As an alternative or addition, the discontinuities can include multiple incisions in the outer layer, such as multiple parallel incisions. The discontinuities can include incisions in the outer layer that define a flap and multiple perforations near the junction of the flap.

[0031] Components of the orthodontic appliance described herein can be fabricated using any suitable method. For example, the outer and inner layers can be heat-formed. The discontinuities can be etched or engraved in the outer layer. In some cases, the discontinuities can include shapes etched in the outer layer.

[0032] In another aspect, an orthodontic appliance can include a housing having a plurality of cavities shaped to receive a patient's teeth, the housing including a first layer and a second layer having a lower stiffness than the first layer. Discontinuities can be formed in the first layer. In various embodiments, the first layer has a modulus of elasticity in the range from about 10,000 psi to about 700,000 psi, and the second layer has a modulus of elasticity in the range from about 100 psi to about 8,000 psi. In alternative embodiments, the second layer has a modulus of elasticity in the range from about 100 psi to about 50,000 psi. The first layer can include the outer layer of the housing, and the second layer can include the inner layer of the housing. Alternatively, the first layer can include the inner layer of the housing, and the second layer can include the outer layer of the housing.

[0033] The design of the discontinuities can vary as desired. For example, the discontinuities can include incisions formed in the first layer. The incisions can at least partially extend around a protrusion formed in the first layer. In some cases, the incisions can be closed incisions, such as an incision enclosing an area of the housing. The incisions can extend from the buccal surface of the first layer to the lingual surface of the first layer. As an alternative or addition, the discontinuities can include a plurality of incisions in the first layer, such as a plurality of parallel incisions. The discontinuities can include incisions in the first layer that define a flap and a plurality of perforations near the junction of the flap.

[0034] The components of the orthodontic appliance described herein can be produced in various ways. For example, the first and second layers can be heat-formed. The discontinuities can be etched or engraved in the first layer. In some cases, the discontinuities can include shapes etched in the first layer.

[0035] In another aspect, the aligners described herein can be included in a series of aligners to provide an orthodontic system for repositioning teeth. Such an orthodontic system can include a plurality of orthodontic aligners, each of which includes a housing that includes more than one cavity that is shaped to receive a patient's teeth. The aligners can be worn successively by the patient or are wearable to move more than one tooth from a first alignment to a second alignment. More than one aligner can include a layered aligner as described herein. For example, a layered aligner of the system can include an aligner housing having a plurality of cavities that are shaped to receive a patient's teeth. The housing can include an outer layer and an inner layer, and the inner layer has a lower stiffness than the outer layer. A discontinuity can be formed in the outer layer. In a plurality of embodiments, the outer layer has a modulus of elasticity in the range from about 10,000 psi to about 700,000 psi, and the inner layer has a modulus of elasticity in the range from about 100 psi to about 8,000 psi. In an alternative embodiment, the inner layer has a modulus of elasticity in the range from about 100 psi to about 50,000 psi.

[0036] The geometry and configuration of the discontinuity can be selected such that more than one force can be applied to the patient's teeth. The discontinuity can include an incision formed in the outer layer. For example, the incision can at least partially extend around a protrusion formed in the outer layer. As another example, the incision can be a closed incision, such as an incision that encloses a region of the housing. The incision can extend from the buccal surface of the outer layer to the lingual surface of the outer layer. In some cases, the discontinuity can include a plurality of incisions in the outer layer, such as a plurality of parallel incisions. The discontinuity can include an incision that defines a flap in the outer layer and a plurality of perforations near the junction of the flap.

[0037] The outer layer and the inner layer of the aligner can be heat formed to form the aligner housing. The discontinuity can be etched or engraved in the outer layer. For example, the discontinuity can include a shape etched in the outer layer.

[0038] In another aspect, an orthodontic system for repositioning a patient's teeth is provided. The orthodontic system can include a plurality of orthodontic appliances, each of the plurality of orthodontic appliances including a housing that includes more than one cavity that is shaped to receive a patient's teeth. The appliances can be worn successively by the patient or are wearable to move more than one tooth from a first alignment to a second alignment. More than one appliance can include a layered appliance as described herein. For example, a layered appliance can include an appliance housing having a plurality of cavities that are shaped to receive a patient's teeth. The appliance housing can include a first layer and a second layer, the second layer having a lower stiffness than the first layer. A discontinuity can be formed in the first layer. In a plurality of embodiments, the first layer has a modulus of elasticity in the range from about 10,000 psi to about 700,000 psi, and the second layer has a modulus of elasticity in the range from about 100 psi to about 8,000 psi. In an alternative embodiment, the second layer has a modulus of elasticity in the range from about 100 psi to about 50,000 psi. The first layer can include an outer layer of the appliance housing, and the second layer can include an inner layer of the appliance housing. Alternatively, the first layer can include an inner layer of the appliance housing, and the second layer can include an outer layer of the appliance housing.

[0039] The geometry and configuration of the discontinuity can be selected based on the force desired to be applied to the patient's teeth. The discontinuity can include an incision formed in the first layer. For example, the incision can at least partially extend around a protrusion formed in the first layer. As another example, the incision can be a closed incision, such as an incision around a region of the housing. The incision can extend from a buccal surface of the first layer to a lingual surface of the first layer. In some cases, the discontinuity can include a plurality of incisions in the first layer, such as a plurality of incisions that are parallel to each other. The discontinuity can include an incision in the first layer that defines a flap, and a plurality of perforations near the junction of the flap.

[0040] The first and second layers of the appliance can be heat formed to form the appliance housing. The discontinuity can be etched or engraved in the first layer. For example, the discontinuity can include a shape etched in the first layer.

[0041] In another aspect, a method for creating an orthodontic appliance as described herein can include providing a shell having a plurality of cavities shaped to receive a patient's teeth. The shell can include an outer layer and an inner layer, the inner layer having a lower stiffness than the outer layer. In various embodiments, the outer layer has a modulus of elasticity in the range from about 10,000 psi to about 700,000 psi, and the inner layer has a modulus of elasticity in the range from about 100 psi to about 8,000 psi. In alternative embodiments, the inner layer has a modulus of elasticity in the range from about 100 psi to about 50,000 psi. The outer and inner layers of the shell can be heat formed. A discontinuity can be formed in the outer layer. The process of forming the discontinuity can include creating an incision in the outer layer, such as an incision that at least partially extends around a protrusion formed in the outer layer. The incision can be a closed incision. In some cases, the incision can extend from the buccal surface of the outer layer to the lingual surface of the outer layer. A discontinuity can also be formed by creating a plurality of incisions in the outer layer, and the plurality of incisions can be parallel to each other. The discontinuity can include an incision that defines a flap in the outer layer, and a plurality of perforations near the junction of the flap. As another example, forming the discontinuity can include etching or engraving the discontinuity in the outer layer. The etching of the discontinuity in the outer layer can include etching a shape in the outer layer.

[0042] In another aspect, a method for creating an orthodontic appliance as described herein is provided. The method can include providing a shell having a plurality of cavities shaped to receive a patient's teeth. The shell can include a first layer and a second layer, the second layer having a lower stiffness than the first layer. In various embodiments, the first layer has a modulus of elasticity in the range from about 10,000 psi to about 700,000 psi, and the second layer has a modulus of elasticity in the range from about 100 psi to about 8,000 psi. In alternative embodiments, the second layer has a modulus of elasticity in the range from about 100 psi to about 50,000 psi. The first layer can include the outer layer of the shell, and the second layer can include the inner layer of the shell. Alternatively, the first layer can include the inner layer of the shell, and the second layer can include the outer layer of the shell.

[0043] The first and second layers of the outer shell can be pre-formed by heating. The discontinuity can be formed in the first layer. The process of forming the discontinuity can include creating incisions in the first layer, such as incisions that at least partially extend around a protrusion formed in the first layer. The incisions can be closed incisions. In some cases, the incisions can extend from the buccal surface of the first layer to the lingual surface of the first layer. The discontinuity can also be formed by creating a plurality of incisions in the first layer, and the plurality of incisions can be parallel to each other. The discontinuity can include incisions that define a flap in the first layer, and a plurality of perforations near the connecting portion of the flap. As another example, forming the discontinuity can include etching or engraving the discontinuity in the first layer. Etching the discontinuity in the first layer can include etching a shape in the first layer.

[0044] Turning now to the drawings, in which like numerals designate like elements throughout the several views, Figure 1AFig. shows an exemplary tooth repositioning aligner or calibrator 100 that can be worn by a patient to effect progressive repositioning of individual teeth 102 in the jaws. The aligner can include a housing (e.g., a continuous polymeric housing or a segmented housing) having tooth receiving cavities that house the teeth and resiliently reposition the teeth. The aligner or portions of the aligner can be indirectly fabricated using a physical model of the teeth. For example, an aligner (e.g., a polymeric aligner) can be formed using a physical model of the teeth and a sheet of a suitable layer of polymeric material. In some instances, the physical aligner is fabricated directly according to a digital model of the aligner, such as using rapid prototyping manufacturing techniques. The aligner can fit over all the teeth in the upper or lower jaw, or fewer than all the teeth. The aligner can be designed to specifically accommodate the patient's teeth (e.g., the topography of the tooth receiving cavities matches the topography of the patient's teeth) and can be fabricated based on a positive or negative model of the patient's teeth generated by an impression, scan, etc. Alternatively, the aligner can be a universal aligner configured to house the teeth without being shaped to match the topography of the patient's teeth. In some cases, only the specific teeth housed by the aligner are to be repositioned by the aligner, while the other teeth can provide a base or anchorage region for holding the aligner in place when the aligner applies forces to one or more of the teeth targeted for repositioning. In some cases, at some point during treatment, some or most or even all of the teeth are to be repositioned. The teeth being moved can also act as a base or anchor for holding the aligner in place when the patient wears the aligner. Generally, no wires or other devices are provided to hold the aligner in place on the teeth. However, in some cases, it can be desirable or necessary to provide corresponding receiving portions or holes 106 in the aligner 100 for individual attachments or other anchors 104 on the teeth 102 so that the aligner can apply selected forces to the teeth. Exemplary aligners including those used in the system are described in numerous patents or patent applications assigned to Align Technology, Inc., including, for example, U.S. Patent Nos. 6,450,807 and 5,975,893, as well as on the company's website accessible on the World Wide Web (see, e.g., the website address “invisalign.com”). Examples of tooth-mounted attachments suitable for use with orthodontic aligners are also described in patents or patent applications assigned to Align Technology, Inc., including, for example, U.S. Patent Nos. 6,309,215 and 6,830,450.

[0045] Figure 1BIllustrated is a tooth repositioning system 110 that includes a plurality of aligners 112, 114, 116. Any of the aligners described herein can be designed and / or configured as part of a set of a plurality of aligners for use in a tooth repositioning system. Each aligner can be configured such that the tooth receiving cavity has a geometry corresponding to an intermediate tooth alignment or a final tooth alignment for the aligner. By placing a series of progressive position adjustment aligners on a patient's teeth, the patient's teeth can be gradually repositioned from an initial tooth alignment to a target tooth alignment. For example, the tooth repositioning system 110 can include: a first aligner 112 that corresponds to an initial tooth alignment; one or more intermediate aligners 114 that correspond to one or more intermediate alignments; and a final aligner 116 that corresponds to a target alignment. The target tooth alignment can be a planned final tooth alignment for the patient's teeth at the end of all planned orthodontic treatment.

[0046] Alternatively, the target alignment can be one of a plurality of intermediate alignments of the patient's teeth during the course of orthodontic treatment that may include a variety of different treatment scenarios, the treatment scenarios including but not limited to cases such as where surgery is recommended; where interproximal reduction (IPR) is appropriate; where further examination is planned; where the anchorage location is optimal; where palatal expansion is desirable; where prosthodontics is involved (e.g., inlays, fillings, crowns, bridges, grafts, veneers, etc.) and the like. Similarly, it is understood that the target tooth alignment can be any planned resultant alignment for the patient's teeth following one or more progressive repositioning phases. Similarly, the initial tooth alignment can be any initial alignment for the patient's teeth that is subsequently followed by one or more progressive repositioning phases.

[0047] Figure 2A method 200 of orthodontic treatment using multiple corrective appliances according to multiple embodiments is shown. The method 200 can be practiced using any of the corrective appliances or groups of corrective appliances described herein. In step 210, a first orthodontic corrective appliance is applied to a patient's teeth to reposition the teeth from a first tooth alignment to a second tooth alignment. In step 220, a second orthodontic corrective appliance is applied to the patient's teeth to reposition the teeth from the second tooth alignment to a third tooth alignment. As needed, the method 200 can be repeated using any suitable number and combination of successive corrective appliances to progressively reposition the patient's teeth from an initial alignment to a target alignment. The corrective appliances can be generated all at once in the same phase or in groups or batches (e.g., at the beginning of a treatment phase), or one corrective appliance at a time, and the patient can wear each corrective appliance until the pressure of each corrective appliance on the teeth can no longer be felt or until the maximum amount of tooth movement characteristic of a given phase has been achieved. Multiple different corrective appliances (e.g., a group) can be designed and even manufactured before the patient wears any of the multiple corrective appliances. After wearing a corrective appliance for an appropriate period of time, the patient can replace the current corrective appliance with the next one in the series until no corrective appliances remain. The corrective appliances are typically not adhered to the teeth, and the patient can place and replace the corrective appliances at any time during the process (e.g., patient-removable corrective appliances). The final corrective appliance or appliances in the series can have a geometry selected to over-correct the tooth alignment. For example, more than one corrective appliance can have a geometry that would (if fully achieved) move individual teeth beyond the tooth alignment that has been selected as "final". Such over-correction is desirable to counteract potential relapse after the repositioning method has terminated (e.g., allowing individual teeth to move back towards their pre-correction positions). Over-correction can also be beneficial for accelerating the correction speed (e.g., a corrective appliance with a geometry positioned beyond the desired intermediate or final position can cause individual teeth to shift towards the position at a greater rate). In such cases, the use of the corrective appliance can be terminated before the teeth reach the position defined by the corrective appliance. Additionally, over-correction can be intentionally applied to compensate for any errors or limitations of the corrective appliance.

[0048] Although the above steps illustrate a method 200 of orthodontic treatment using multiple corrective appliances according to embodiments, those of ordinary skill in the art will recognize various variations based on the teachings described herein. Some steps can include sub-steps. Multiple steps can be repeated whenever beneficial to the treatment. More than one step of the method 200 can be applied to any suitable orthodontic corrective appliance, such as the embodiments described herein.

[0049] For the orthodontic systems and treatments described herein, various embodiments and configurations of the appliance can be considered. For example, the appliance can include multiple layers, including at least one relatively elastic layer and at least one relatively rigid layer. As used herein, "relatively elastic" and "relatively rigid" can mean that the relatively rigid layer is more rigid (stiff) than the relatively elastic layer. For example, the (relatively) rigid layer can have a modulus of elasticity in the range from about 10,000 psi to about 700,000 psi, and the (relatively) elastic layer can have a modulus of elasticity in the range from about 100 psi to about 8,000 psi, or from about 100 psi to about 50,000 psi. The elastic layer and the rigid layer can be arranged in any suitable manner to form the appliance, such as the elastic layer being inside the appliance and the rigid layer being outside the appliance. As used herein, "inside" can be used to refer to the position of the appliance that is adjacent to or nearly adjacent to the teeth being contained when the appliance is worn, and "outside" can be used to refer to the position that is opposite or nearly opposite to the teeth being contained when the appliance is worn. "Inside" and "outside" as used herein can also refer to relative positioning rather than absolute positioning. In alternative embodiments, other configurations can be used, such as the appliance being formed by an elastic layer on the outside and a rigid layer on the inside.

[0050] The number of layers in the layered orthodontic appliance can be varied according to desire. The appliance can include only one elastic layer and only one rigid layer. Alternatively, in addition to the elastic layer and the rigid layer, the appliance can include other layers, such as an intermediate layer sandwiched between the elastic layer and the rigid layer. Optionally, the appliance can include multiple elastic layers and multiple rigid layers. As will be understood, the layered appliances described herein can apply forces to more than one tooth of a patient to cause various tooth movements corresponding to a desired treatment process.

[0051] Figure 3A FIG. shows a portion of a layered orthodontic appliance 300 according to multiple embodiments. The appliance 300 can include a housing 302 having one or more tooth-receiving cavities 303 shaped to receive a patient's teeth. The housing 302 can include an outer layer 304 and an inner layer 306. Thus, when the appliance 300 is worn on the patient's teeth, the inner layer 306 can contact the teeth while the outer layer 304 can be non-contact with the teeth. In some cases, the inner surface of the inner layer 306 can be covered by one or more additional layers of material (not shown) such that the inner layer 306 does not directly contact the teeth. These additional layers can be mainly provided to improve the contact surface for contact between the housing 302 and the teeth and / or gums, and can thus be thinner than the outer layer 304 and the inner layer 306. Optionally, one or more additional layers can also be located at other positions of the housing 302, such as between the outer layer 304 and the inner layer 306, on the outer surface of the outer layer 304, etc.

[0052] The outer layer 304 and the inner layer 306 can both span the entire aligner 300, or only span a certain part of the aligner 300. In multiple embodiments, the outer layer 304 and the inner layer 306 extend from the lingual surface 308 of the aligner 300 towards the buccal surface 310, so as to cover the lingual surface, occlusal surface, and buccal surface of the teeth received in the aligner 300. Optionally, one or more portions of the outer layer 304 and / or the inner layer 306 can also extend gingivally. The outer layer 304 and the inner layer 306 can be laminated with each other such that when the aligner 300 is worn, they cover the same or similar portions of the patient's teeth. The outer layer 304 and the inner layer 306 can be joined to each other at the laminated portion (e.g., by using one or more discrete attachment points and / or over one or more continuous attachment regions), thereby forming a double-layered outer shell structure. In multiple embodiments, the outer layer 304 and the inner layer 306 are laminated throughout the entire aligner 300 such that the entire aligner 300 is at least double-layered. Alternatively, the outer layer 304 and the inner layer 306 may not be laminated at some portions of the aligner 300 such that the teeth received in these portions are covered by the outer layer 304 rather than the inner layer 306, or vice versa. Some portions of the aligner 300 can be formed of other materials or components and thus may not include either the outer layer 304 or the inner layer 306.

[0053] The outer layer 304 can be relatively rigid, and the inner layer 306 can be relatively elastic. As a result, the stiffness of the inner layer 306 can be lower than the stiffness of the outer layer 304. The properties of the aligner 300 at the double-layered portion (e.g., stiffness) can be mainly determined by the properties of the outer layer 304, with little contribution from the elastic inner layer 306. Therefore, these portions of the aligner 300 can be relatively rigid and can hardly deform or not deform when placed on the patient's teeth.

[0054] Conversely, the portions of the aligner 300 where there are discontinuities in the outer layer 304 can allow a greater contribution from the inner layer 306 and thus can be relatively flexible and / or deformable, as will be discussed in further detail below.

[0055] It is possible to change the properties of the outer layer 304 and the inner layer 306 according to expectations. For example, the inner layer 306 can have a modulus of elasticity of approximately 600 psi, or a modulus of elasticity in the range from approximately 100 psi to approximately 8000 psi, or a modulus of elasticity in the range from approximately 100 psi to approximately 50000 psi. The outer layer 304 can have a modulus of elasticity of approximately 100000 psi, or a modulus of elasticity in the range from approximately 10000 psi to approximately 700000 psi. The modulus of elasticity of the inner layer 306 can be approximately 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, or 10% of the modulus of elasticity of the outer layer 304. In some embodiments, the rigidity of each layer is related to the thickness of the layer. The outer layer 304 and the inner layer 306 can have the same thickness or different thicknesses. For example, the thickness of the inner layer 304 can be approximately 0.02 mm, or in the range from approximately 0.01 mm to approximately 1.0 mm. The thickness of the outer layer 306 can be approximately 0.05 mm, or in the range from approximately 0.02 mm to approximately 1.0 mm. The thickness of the inner layer 304 can be approximately 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, or 10% of the thickness of the outer layer 306.

[0056] In an alternative embodiment, the outer layer 304 can be relatively elastic and the inner layer 306 can be relatively rigid, such that the stiffness of the outer layer 304 is lower than the stiffness of the inner layer 306. It should be understood that although the various embodiments presented herein describe a housing having a rigid outer layer and an elastic inner layer, the theory of the present disclosure can also be applied to alternative configurations of the layered aligner, such as, for example, an aligner including a housing having an elastic outer layer and a rigid inner layer.

[0057] The layered aligner described herein can include one or more discontinuities formed in more than one layer, such as in the outer layer, inner layer, elastic layer, rigid layer, or a combination thereof. In multiple embodiments, the one or more discontinuities are formed only in a single layer, such as only the outer layer, only the inner layer, only the elastic layer, or only the rigid layer, such that the other layers do not include any discontinuities. Although the various embodiments herein describe discontinuities formed only in the rigid outer layer of the layered orthodontic aligner, it should be understood that alternative embodiments can include discontinuities formed in other layers, such as the elastic inner layer, rigid inner layer, etc.

[0058] The discontinuities can include any suitable number and combination of incisions, flaps, holes (e.g., openings, windows, slits, notches), or deformations (e.g., protrusions, depressions, reliefs) formed in any suitable portion of a layer such as an outer layer (e.g., in the buccal surface, lingual surface, occlusal surface, and / or gingival surface). For example, the size (e.g., length, width, depth, surface area, etc.) and / or shape of the discontinuities can be calculated to achieve a specific degree of aligner compliance. The discontinuities can be linear, curved, curvilinear, circular, oval, triangular, square, rectangular, polygonal, or any other regular or irregular shape, or a suitable portion or combination of the above shapes. The orientation of the discontinuities can be determined in any direction, such as along the occlusal-gingival direction, mesial-distal direction, or buccal-lingual direction.

[0059] The number, geometry, and configuration of the discontinuities can be selected to adjust the local properties (e.g., compliance or stiffness) of the aligner and / or to affect the forces transmitted to the patient's teeth via the aligner. The forces can be provided, in whole or in part, by the interaction of a layer (e.g., an elastic inner layer) with the discontinuities and can be provided by the deformation, displacement, and / or shift of the discontinuities and / or the inner layer when the aligner is worn on the patient's teeth. The geometry and configuration of the discontinuities described herein can be selected to control the magnitude and / or direction of the forces applied to the teeth.

[0060] Figure 3B Discontinuities 312 formed in the outer layer 304 of aligner 300 according to multiple embodiments are shown. The discontinuities 312 can be formed individually in the outer layer 304 such that the inner layer 306 is left intact. The inner layer 306 can be exposed through the discontinuities 312. The presence of the discontinuities 312 can change the properties of the aligner 300 at or near the discontinuities 312. For example, in multiple embodiments, the exposed inner layer 306 is less rigid than the outer layer 304 such that the local compliance of the aligner 300 at or near the discontinuities 312 can be enhanced compared to other portions of the aligner 300. In some cases, e.g., when the aligner is worn, the discontinuities 312 can be deformable (e.g., capable of changing with respect to shape, size) and / or displaceable, which can also result in an enhancement of the local compliance of the aligner. The amount of local compliance can be used to control the resultant force (e.g., magnitude, direction) applied to the underlying teeth.

[0061] In addition, the inner layer 306 can interact with the discontinuity 312, such as by applying a force on the discontinuity 312 or on a portion of the outer layer 304 near the discontinuity 312. As described in more detail below, when the orthodontic appliance 300 is worn, these forces can be caused, in whole or in part, by deformation or displacement of the discontinuity 312 and / or the inner layer 306. The forces generated by the interaction of the inner layer 306 and the discontinuity 312 can be transmitted via the housing 302 to the underlying teeth, thereby causing repositioning of more than one tooth. The force can be applied directly to the teeth via the housing 302. Alternatively, the housing 302 can apply the force indirectly, for example, via one or more attachments (not shown) mounted on more than one tooth. In such a case, the discontinuity 312 can be shaped to accommodate the attachment.

[0062] In Figure 3B FIG. 5, the discontinuity 312 is depicted as an arcuate cutout that forms a semi-circular flap 314 in the outer layer 304. Alternatively, cutouts and flaps 314 of other geometric shapes (e.g., oval, square, rectangular, triangular, polygonal, etc.) can be used. The edges of the flap 314 can be joined to the edges of adjacent portions of the outer layer 304 by the underlying inner layer 306. The flap 314 can be offset outwardly and / or inwardly relative to the surrounding portion of the outer layer 304. In some cases, the arcuate cutout can extend around features such as protrusions, depressions, or reliefs formed in the housing 302. Optionally, the arcuate cutout can be positioned adjacent to or near a tooth-mounted attachment when the patient wears the orthodontic appliance 300.

[0063] Figures 3C to 3F FIG. 6 shows another exemplary discontinuity according to multiple embodiments, which can be provided as part of the orthodontic appliance 300. Figure 3C FIG. 7 shows a discontinuity formed as a closed cutout 316. The closed cutout 316 encloses an area 318 of the outer layer 304, thereby separating the area 318 from the remainder of the outer layer 304. The inner layer 306 can span the closed cutout 316 to join the edges of the enclosed area 318 to the edges of adjacent portions of the outer layer 304. The closed cutout 316 can be a circular cutout as depicted herein, or any other suitable shape. The separated area 318 defined by the closed cutout 316 can include features such as protrusions, depressions, or reliefs. The separated area 318 can be displaced relative to the surrounding area of the outer layer 304.

[0064] Figure 3DDisclosed is a discontinuity formed as an elongated linear incision 320. The linear incision 320 can extend from the buccal surface of the outer layer 304 to the lingual surface. The size of the linear incision 320 can vary as desired. For example, the linear incision 320 can extend from the buccal edge to the lingual edge of the aligner 300, separating the outer layer 304 into separated segments 322, 324. The segments 322, 324 can be interconnected by a portion of the inner layer 306 that spans the linear incision 320. When the aligner 300 is placed on the patient's teeth, the segments 322, 324 can be displaced relative to each other. In multiple embodiments, when the segments 322, 324 at least partially cover teeth adjacent to the interproximal region, the linear incision 320 is positioned adjacent to or near the interproximal region between the teeth.

[0065] Accordingly, the segments 322, 324 can be shaped to receive a tooth or a portion of a tooth.

[0066] Figure 3E Disclosed is a discontinuity formed as a plurality of elongated linear incisions 326. Any suitable number of linear incisions 326 can be used. The linear incisions 326 can have the same or similar dimensions (e.g., length, width). Similar can mean that the variation in dimensions is no more than 50% of the maximum value of the corresponding dimension in the aligner, no more than 25% of the maximum value, or no more than 10% of the maximum value. Alternatively, some of the incisions 326 can have different dimensions from other incisions 326, e.g., the variation is more than 10% of the maximum value of the corresponding dimension in the aligner, more than 25% of the maximum value, or more than 50% of the maximum value. Some or all of the linear incisions 326 can be parallel incisions. Conversely, some or all of the linear incisions 326 can not be parallel to each other. The linear incisions 326 can be spaced apart from each other at a specific distance. The gaps between the linear incisions 326 can be the same or can vary. The portion of the outer layer 304 adjacent to the linear incisions 326 can be connected by the inner layer 306 under the incisions 326. When the patient wears the aligner 300, the incisions 326 can deform (e.g., stretch, widen).

[0067] Figure 3F Disclosed is a discontinuity formed as an etched shape 328 in the outer layer 304. The shape 328 can be etched only partially in the outer surface of the outer layer 304 such that the inner layer 306 is not exposed. Alternatively, the etching can penetrate the entire depth of the outer layer 304 to expose the inner layer 306. The etching of the outer layer 304 can reduce the thickness of the outer layer 304 at the discontinuity, which can change the properties (e.g., stiffness) of the aligner 300 at or near the discontinuity. For example, the presence of the etched shape 328 can increase the influence of the inner layer 306 on the local compliance of the aligner 300 (e.g., reduce local compliance).

[0068] While other geometric structures can also be used, the etched shape 328 is depicted herein as a collapsible structure including a ring 330 and a disk 332. The inner layer 306 can connect the ring 330 and the disk 332. In the collapsed configuration of the etched shape 328 (e.g., when the orthodontic appliance 300 is not being worn by the patient), the ring 330 and the disk 332 can be in a plane that is substantially the same as the peripheral portion of the outer layer 304. In the expanded configuration of the etched shape 328 (e.g., when the orthodontic appliance 300 is being worn by the patient), the intervening portions of the ring 330, the disk 332, and the inner layer 306 can project outwardly from the surrounding outer layer 304 to form a receiving portion. The receiving portion can be shaped to receive, for example, an attachment mounted on the underlying tooth and apply a force to the tooth via the attachment.

[0069] Figures 3G to 3I Discontinuities similar to those depicted in Figure 3B are shown, which are formed to define an incision 334 of a flap 336 in the outer layer 304. The flap 336 can be offset relative to the peripheral portion of the outer layer 304, for example, to accommodate the underlying tooth surface, housing features, and / or tooth attachments. To increase the range of movement of the flap 336 and / or reduce the magnitude of the force required to offset the flap 336, it can be beneficial to modify the outer layer 304 to reduce the flexural resistance of the material at or near the connection portion of the flap 336. This can be achieved by forming more than one discontinuity in the outer layer 304 at or near the connection portion. In multiple embodiments, the discontinuities can be positioned to define a connection portion that flexes during offset of the flap 336. To provide an appropriate amount of flexural resistance at or near the connection portion, any suitable number and combination of discontinuities can be used, and the geometry (e.g., size, shape) and configuration of the discontinuities can be varied as desired. For example, Figure 3G shows a plurality of perforations 338 formed in the outer layer 304 at the connection portion of the flap 336. The perforations 338 can be oval-shaped, as Figure 3G depicted, or any other suitable geometry (e.g., circular, square, triangular, polygonal, etc.). As another example, Figure 3H shows a plurality of small circular perforations 340 formed in the outer layer 304 at the connection portion. At least some of the discontinuities presented herein can extend through the entire thickness of the outer layer 304, thereby exposing the underlying inner layer 306. In alternative embodiments, the discontinuities can extend only partially through the outer layer 304, thereby reducing the thickness of the material at or near the connection portion. For example, Figure 3IA slot 342 formed in the outer layer 304 near the junction of the flap 336 is shown. The end of the slot 342 may contact the incision 334. In an alternative embodiment, the end of the slot 342 may not contact the incision 334. The slot 342 can be etched or engraved in the outer layer 304 to a depth less than the thickness of the outer layer 304. The dimensions (e.g., length, width, depth) and shape (e.g., straight, curved, curvilinear) of the slot 342 can be configured to optimize the flexibility of the flap 336.

[0070] The layered orthodontic appliance described herein can be worn by a patient to apply forces to one or more underlying teeth and thereby effect various tooth movements. The direction and extent of the resultant tooth movement can be determined based on the geometry, configuration, and properties of the discontinuity, inner layer, and / or outer layer. Additionally, the appliance described herein can include various features (e.g., protrusions, depressions, slots, notches, rounded heads, reliefs) formed in the appliance housing (e.g., in the inner layer and / or outer layer) that can engage the teeth at discrete points and / or over continuous regions to further affect the magnitude and / or direction of the forces applied to the teeth. The number, geometry, and configuration of such features can be selected based on the desired movement of the target teeth.

[0071] Figure 4A and 4B A layered orthodontic appliance 400 having a discontinuity 402 is shown in accordance with multiple embodiments. The appliance 400 can include a housing 404 formed by an outer layer 406 and an elastic inner layer 408, with a portion of the inner layer 408 exposed through the discontinuity 402, depicted herein as an elongate straight incision. In other embodiments, there may be no portion of the inner layer that is exposed through the discontinuity, e.g., in embodiments where the discontinuity does not penetrate the entire outer layer. When the appliance 400 is placed on a patient's teeth 410 ( Figure 4B), the discontinuity 402 may be deformed by an intentional mismatch between the patient's current tooth arrangement and the tooth arrangement specified by the geometry of the appliance 400. For example, the elongated linear cutout of the discontinuity 402 may be widened into an elongated hole. Additionally, corresponding to the deformation of the discontinuity 402, one or more portions of the inner layer 408 spanning the discontinuity 402 may also be deformed (e.g., stretched). The resistance of the inner layer 408 to deformation enables forces to be applied to the discontinuity 402 and / or surrounding portions of the outer layer 406. Some or all of these forces may be transmitted to the underlying teeth, causing one or more teeth to move with respect to up to six degrees of freedom of motion (e.g., translation, rotation, inward push, extrusion, tilting, twisting, etc.). For example, the interaction of the discontinuity 402 with the inner layer 408 may produce tooth movement (e.g., arrow 412) that reduces the interproximal space between the teeth. Alternatively or additionally, the appliance 400 may be used to produce other types of tooth movement, such as tooth movement that increases the interproximal space between the teeth (e.g., to correct a malocclusion, to accommodate an inlay or other denture, etc.). As the teeth are repositioned, the deformation of the discontinuity 402 and / or the inner layer 408 may be reduced, thereby reducing the amount of force pressed by the appliance 400 on the teeth.

[0072] Figure 5A and 5B A cross-sectional view of a layered orthodontic appliance 500 having a discontinuity 502 is shown according to various embodiments. The appliance 500 can include an outer shell 504 having an outer layer 506 and an elastic inner layer 508. The discontinuity 502 can be a cutout in the outer layer 506 that forms a flap, Figure 3B and Figures 3F to 3I The embodiment depicted is similar. The edges of the incision can be connected by the inner layer 508. The outer shell 504 can include features such as protrusions 510 (e.g., round heads, knobs, etc.) that are located on the flap and extend into the inner cavity of the aligner 500. When the tooth 512 is received in the aligner 500, the protrusions 510 and the flap can be displaced outwardly following the surface topography of the tooth 512. The elastic inner layer 508 can resist displacement by applying a force to the outer layer 506 at or near the discontinuity 502, thereby pulling the protrusions 510 and the flap inwardly toward the tooth surface (e.g., arrow 514). The applied force can be transmitted to the tooth 512 primarily at the contact point between the surface of the tooth 512 and the protrusion 510. The application of force to the contact point can cause various movements of the tooth 512, such as tilting movement. In some cases, multiple protrusions can be used in combination with multiple discontinuities to provide multiple contact points for more precise application of force to the teeth.

[0073] For the layered aligners described herein, various different embodiments or configurations can be considered. For example, the aligner can include various different configurations of elastic layers and / or rigid layers, including different compositions and / or structures of elastic materials and / or rigid materials. The material forming the layer can include a single continuous layer of material, or multiple layers of the same material, multiple layers of different materials, or a combination of some layers of the same material and more than one layer of different materials. The properties of the material layer, such as toughness, elasticity, hardness / softness, color, etc., can be determined based at least in part on the selected material, layers of material, and / or layer thickness. In some cases, the layer can be configured such that more than one property is uniform along the length or a portion (or the entire layer) of the layer. Additionally, more than one property of the layer can vary along the length or a portion of the layer (or the entire layer). The variation (or variability) can refer, for example, to a change in more than one property that is greater than 10%, greater than 25%, or greater than 50% of the maximum value of the corresponding property of the elastic material. For example, the layer can have a generally uniform thickness along the length or a portion, or the thickness can vary along the length / portion. A generally uniform thickness can refer to a change in more than one property (e.g., the absolute value of the difference between any two values of a property of the aligner) that is not greater than 50%, not greater than 25%, or not greater than 10% of the highest value of the corresponding property of the elastic material. As will be appreciated, the layer or characteristics of the layer can be selected to affect the forces applied to the patient's teeth or to affect the direction of tooth movement for a desired particular treatment.

[0074] Figure 6 Method 600 for manufacturing an orthodontic aligner according to multiple embodiments is shown. Method 600 can be applied to any embodiment of the orthodontic aligner described herein.

[0075] In step 610, a shell is provided that has a plurality of cavities shaped to receive teeth. The shell can include a first layer and a second layer having a lower stiffness than the first layer, such that the first layer is relatively rigid and the second layer is relatively elastic. For example, the first layer can be the outer layer of the shell, and the second layer can be the inner layer of the shell. Alternatively, the first layer can be the inner layer of the shell, and the second layer can be the outer layer of the shell. The second layer and the first layer can be formed of any suitable material or combination of materials. For example, the first layer and / or the second layer can be formed of a biocompatible material suitable for orthodontics, such as latex. In some cases, the first layer and the second layer are transparent, translucent, or colored to enhance the aesthetics of the appliance when worn by the patient. The first layer (e.g., the relatively rigid layer) can be manufactured using a material similar to or corresponding to the material used for a conventional single-layer appliance shell, such as a polymeric sheet. The material for the first layer can be harder than the material typically used for a single-layer shell. The second layer (e.g., the relatively elastic layer) can be made of any suitable elastic material, and such a material can be provided as strips, bands, plates, meshes, coatings, layers, or a suitable combination thereof. The properties of the elastic layer (e.g., length, width, thickness, area, shape, cross-section, stiffness, etc.) can be uniform over most of the elastic material or can vary. For example, different portions of the second layer can have different thicknesses to vary the local compliance of the appliance shell. Additionally, in some cases, the second layer can have anisotropic properties. As an example, the second layer can be relatively compliant along a first direction and less compliant (or non-compliant) along a second direction. The directionality of the second layer can be used to control the direction of the resultant force applied to the teeth. Optionally, the second layer can be formed with topological features (e.g., molded, painted, textured, roughened, etc.) to increase the surface friction between the shell and the enamel of the received teeth. For example, such features can be used to enhance the ability of the shell to clamp onto the teeth when worn by the patient.

[0076] The outer shell can be manufactured using any suitable method, such as thermoforming, rapid prototyping, stereolithography, or computer numerical control (CNC) milling. For example, the first layer and the second layer can be thermoformed to form the outer shell. The layers can be thermoformed simultaneously or sequentially. The inner layer can be thermoformed first, and then the outer layer can be thermoformed over the inner layer. The thermoforming process can directly bond the first layer to the second layer (e.g., by thermal bonding) without using adhesives or other indirect bonding methods. As an alternative or addition, adhesives can be used to connect the first layer to the second layer to each other. In some cases, the outer layer can be formed first, and the inner layer can then be connected to the outer layer (e.g., by dipping, spraying, extrusion, coating, etc.), or vice versa. The double-layer outer shell described herein can be manufactured based on a physical or digital model of a patient's teeth. The model can be generated from a dental impression or scan (e.g., the patient's oral cavity, a positive or negative mold of the patient's oral cavity, or a dental impression formed from the patient's oral cavity).

[0077] In step 620, discontinuities are formed in the first layer. Any method suitable for creating incisions or removing material from the first layer can be used to create more than one discontinuity. For example, the discontinuities can be engraved or etched in the first layer (e.g., using a CNC or laser-based method). The discontinuities can be formed without affecting the second layer. The discontinuities can penetrate the entire thickness of the first layer to expose the underlying second layer, or can only partially penetrate the first layer such that the second layer is not exposed. In multiple embodiments, the discontinuities are only located in the first layer such that the second layer remains intact.

[0078] Although the above steps illustrate method 600 for manufacturing an orthodontic appliance according to an embodiment, those of ordinary skill in the art will recognize various variations based on the teachings described herein. Some steps can include sub-steps. Multiple steps can be repeated whenever beneficial to treatment. More than one step of method 600 can be applied to any suitable orthodontic appliance, such as the embodiments described herein. The order of the steps can vary. For example, in an alternative embodiment, a layered orthodontic appliance can be manufactured by first setting the first layer (e.g., the outer layer) and forming discontinuities in the first layer, as described above. Using any of the techniques discussed herein, the first layer can then be connected to the elastic second layer (e.g., the inner layer) to form a double-layer outer shell.

[0079] An orthodontic appliance is manufactured or designed to utilize one or more physical or digital representations of a patient's teeth. The representation of the patient's teeth can include a representation of the patient's teeth in their current alignment and can also include a representation of the patient's teeth repositioned in more than one treatment phase. A treatment phase can include a desired or target alignment of the patient's teeth, such as a desired final alignment of the teeth. A treatment phase can also include an intermediate alignment of one or more teeth (e.g., a planned intermediate alignment) that represents the alignment of the patient's teeth as the teeth move from a first alignment (e.g., an initial alignment) to a second or desired alignment (e.g., a desired final alignment).

[0080] Figure 7 FIG. 700 shows a method for digitally planning orthodontic treatment and / or designing or manufacturing an orthodontic appliance according to multiple embodiments. Method 700 can be applied to any of the treatment processes described herein and can be executed by any suitable digital processing system.

[0081] In step 710, a digital representation of the patient's teeth is received. The digital representation can include surface topography data of the patient's oral cavity (including teeth, gingival tissue, etc.). The surface topography data can be generated by directly scanning the oral cavity, a physical model (positive or negative) of the oral cavity, or an impression of the oral cavity using a suitable scanning device (e.g., a hand-held scanner, a desktop scanner, etc.).

[0082] In step 720, one or more treatment phases are generated based on the digital representation of the teeth. The treatment phase can be a progressive repositioning phase of an orthodontic treatment process that is designed to move one or more of the patient's teeth from an initial tooth alignment to a target alignment. For example, a treatment phase can be generated as follows: determining the initial tooth alignment represented by the numerical representation, determining the target tooth alignment, and determining the movement path required for one or more of the teeth in the initial alignment to achieve the target tooth alignment. The movement path can be optimized based on minimizing the total movement distance, preventing tooth-to-tooth collisions, avoiding more difficult-to-achieve tooth movements, or other suitable criteria.

[0083] In step 730, at least one orthodontic appliance is fabricated based on the generated treatment phase. For example, a set of appliances can be fabricated to be worn sequentially by a patient to progressively reposition teeth from an initial alignment to a target alignment. Some appliances can be shaped to accommodate the tooth alignment specified by one treatment phase. As an alternative or in combination, some appliances can be shaped to accommodate a tooth alignment different from the target alignment for the corresponding treatment phase. For example, as described previously, an appliance can have a geometry corresponding to an overcorrected tooth alignment. Such an appliance can be used to ensure that an appropriate amount of force is applied to the teeth as they approach or reach the desired target position for their treatment phase. As another example, an appliance can be designed to apply a specified force system to the teeth and can not have a geometry corresponding to any current or planned patient tooth alignment.

[0084] The set of appliances can include more than one of the layered appliances described herein. The properties of the inner and outer layers (e.g., geometry, construction, material properties) of these appliances and the construction of more than one discontinuity in the outer layer can be selected to induce the tooth movement specified by the corresponding treatment phase. In multiple embodiments, a layered appliance associated with a treatment phase can omit more than one portion of the inner or outer layer. Which portions to omit can be determined based on the particular tooth movement to be achieved during the treatment phase. For example, when contacting the teeth, a relatively elastic inner layer can create increased frictional forces compared to the outer layer. Thus, in some cases, removal of a portion of the inner layer can facilitate movement of the teeth relative to the appliance. Conversely, in embodiments where increased frictional forces between the tooth surface and the appliance enhance the force applied to the teeth, the presence of the inner layer at certain locations can be advantageous.

[0085] The design of the layered appliances provided herein can be determined via suitable computer software or other digital-based methods. For example, computer modeling methods can be used to determine an appropriate force system that includes more than one force and / or torque to be applied to the teeth to induce the desired tooth movement. During the appropriate phase of treatment, the arrangement and properties of the inner and outer layers and the construction of more than one discontinuity in the outer layer can be designed to provide the specified force and / or torque when the patient wears the appliance. Other examples of digital modeling and force analysis techniques suitable for the embodiments provided herein are described in Patent Nos. 12 / 623,340, 12 / 324,714, and 13 / 365,167, which are incorporated herein by reference in their entirety, and in U.S. Patent No. 8,439,672. Digital models created using such methods can be used as input to a computer-controlled manufacturing system for fabricating the appliance.

[0086] While the above steps illustrate a method 700 for orthodontic treatment and / or the design or manufacture of an orthodontic appliance according to an embodiment of a numerical plan, those of ordinary skill in the art will recognize various variations based on the teachings herein. Some steps may include sub-steps. Multiple steps may be repeated whenever beneficial to treatment. More than one step of method 700 may be applied to the manufacture of any orthodontic appliance, such as the embodiments described herein. Some steps may be optional, and the order of steps may be varied. In some cases, various permutations or segmentation of treatment phases may not be necessary for the design and / or manufacture of the appliance. As Figure 7 shown by the dashed line of Figure 7 , the design and / or manufacture of an orthodontic appliance, and possibly a particular orthodontic treatment, may include: using a representation of a patient's teeth (e.g., receiving a digital representation 710 of a patient's teeth); and subsequently designing and / or manufacturing an orthodontic appliance based on the representation of the patient's teeth in the arrangement represented by the received representation. For example, a positive or negative mold may be generated based on the patient tooth representation (e.g., as in step 710), and then an inner layer and an outer layer may be thermoformed over the positive or negative mold to form the appliance housing described in various embodiments herein.

[0087] Figure 8 FIG. Figure 8 is a simplified block diagram of a data processing system 800 that may be used in performing the methods and processes described herein according to multiple embodiments. Data processing system 800 generally includes at least one processor 802 that communicates with one or more peripheral devices via a bus subsystem 804. These peripheral devices generally include a storage subsystem 806 (a memory subsystem 808 and a file storage subsystem 814), a set of user interface input and output devices 818, and an interface 816 to an external network. The interface is schematically shown as a "network interface" block 816 and is coupled via a communication network interface 824 to a corresponding interface device in other digital processing systems. Digital processing system 800 may include, for example, more than one computer, such as a personal computer, a workstation, a mainframe computer, a laptop computer, etc.

[0088] The user interface input device 818 is not limited to any particular device and can generally include, for example, a keyboard, a pointing device, a mouse, a scanner, an interactive display, a touchpad, a joystick, etc. Similarly, various user interface output devices can be used in the system of the present invention and can include, for example, one or more of a printer, a display (e.g., visual, non-visual) system / subsystem, a controller, a projection device, an audio output, etc.

[0089] The storage subsystem 806 retains the basic required programming, including computer-readable media having instructions (e.g., operation instructions, etc.) and data structures. The program modules discussed herein are typically stored in the storage subsystem 806. The storage subsystem 806 generally includes a memory subsystem 808 and a file storage subsystem 814. The memory subsystem 808 generally includes several memories (e.g., RAM 810, ROM 812, etc.), which include computer-readable memories for storing fixed instructions, instructions and data during program execution, basic input / output systems, etc. The file storage subsystem 814 provides persistent (non-volatile) storage for program and data files and can include more than one removable or fixed drive or medium, hard disk, floppy disk, CO-ROM, DVD, optical drive, etc. More than one storage system, drive, etc. can be located at a remote location and thus be connected via a server on a network or via the Internet / World Wide Web. In this document, the term "bus subsystem" is generally applied to include any mechanism that enables the various components and subsystems to communicate with each other as expected and can include various suitable components / systems known or considered suitable for this purpose. It should be realized that the various components of the system can and do not have to be in the same physical location but can be connected via various local area network or wide area network media, transmission systems, etc.

[0090] The scanner 820 includes any device for obtaining a digital representation (e.g., an image, surface topography data, etc.) of a patient's teeth (e.g., by scanning a physical model such as casts 821 of the teeth, by scanning an impression taken from the teeth, or by directly scanning the oral cavity), the digital representation of the teeth being obtainable from the patient or a treatment professional such as an orthodontist, and including means for providing the digital representation to the digital processing system 800 for further processing. The scanner 820 can be located at a remote location relative to the other components of the system and can communicate image data and / or information to the digital processing system 800, for example, via the network interface 824. The manufacturing system 822 manufactures the orthosis 823 based on a treatment plan that includes dataset information received from the digital processing system 800. The manufacturing machine 822 can be located, for example, at a remote location and receives the dataset information from the digital processing system 800 via the network interface 824.

[0091] As used herein, A and / or B includes more than one A or B and combinations thereof, such as A and B.

[0092] While the preferred embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art will make numerous variations, changes, and substitutions without departing from the present invention. It should be understood that various alternatives to the embodiments of the present invention described herein may be employed in practicing the present invention.

[0093] Many different combinations of the embodiments described herein are possible, and such combinations are considered to be a part of this disclosure. In addition, all features discussed in connection with any one of the embodiments herein can be readily applied to other embodiments herein. It is intended that the following claims define the scope of the present invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.

Claims

1. An orthodontic appliance, comprising: a housing that includes a plurality of cavities shaped to receive a patient's teeth, an inner layer, and an outer layer; a discontinuity formed on the outer layer of the housing, wherein the discontinuity is configured to deform when the orthodontic appliance is worn by the patient, and wherein as the patient's teeth are repositioned, the deformation of the discontinuity decreases, wherein the inner layer of the housing resists the deformation of the discontinuity when the orthodontic appliance is worn by the patient, and wherein the resistance of the inner layer to the deformation causes a force to be transmitted to the underlying teeth, thereby causing movement of more than one of the patient's teeth.

2. The orthodontic appliance according to claim 1, wherein, the deformation of the discontinuity includes stretching of the discontinuity.

3. The orthodontic appliance according to claim 1, wherein, when the orthodontic appliance is worn by the patient, the deformation of the discontinuity transmits a force to the patient's teeth.

4. The orthodontic appliance according to claim 3, wherein, the force transmitted to the patient's teeth includes at least one of a translational force, a rotational force, an intrusive force, an extrusive force, an angulatory force, or a torsional force.

5. The orthodontic appliance according to claim 3, wherein, the discontinuity is an elongate linear incision.

6. The orthodontic appliance according to claim 5, wherein, the discontinuity is an elongate hole when deformed.

7. The orthodontic appliance according to claim 1, wherein, the discontinuity includes an incision in the outer layer of the housing on the inner layer.

8. An orthodontic appliance, comprising: a housing that includes a plurality of cavities shaped to receive a patient's teeth, an inner layer, and an outer layer; a discontinuity formed on the outer layer of the housing, wherein when the orthodontic appliance is worn by the patient, a portion of the housing near the discontinuity is configured to protrude outward, wherein one of the inner layer and the outer layer resists the outward protrusion by applying a force to the other of the inner layer and the outer layer at the portion of the housing near the discontinuity.

9. The orthodontic appliance according to claim 8, wherein, the inner layer resists the outward protrusion by applying a force to the outer layer.

10. The orthodontic appliance according to claim 8, wherein, the outer layer resists the outward protrusion by applying a force to the inner layer.

11. The orthodontic appliance according to claim 8, wherein, the discontinuity is configured to transmit a force to the patient's teeth at the portion of the housing near the discontinuity.

12. The orthodontic appliance according to claim 8, wherein, the outward protrusion of the discontinuity deforms the geometry of the discontinuity.

13. A method of manufacturing an orthodontic appliance, the method comprising: forming a housing that includes a plurality of cavities shaped to receive a patient's teeth, the housing being formed with an inner layer and an outer layer; forming a discontinuity on the outer layer of the housing; Wherein, the discontinuous portion is configured such that when the orthodontic appliance is worn by a patient, the discontinuous portion deforms, and wherein, as the patient's teeth are repositioned, the deformation of the discontinuous portion decreases. Wherein, the inner layer of the outer shell resists the deformation of the discontinuous portion when the orthodontic appliance is worn by a patient, and wherein the resistance of the inner layer to the deformation causes a force to be transmitted to the underlying teeth, thereby causing movement of more than one of the patient's teeth.

14. The method according to claim 13, Wherein, the method further comprises: selecting a geometry and configuration of the discontinuous portion to control a magnitude and / or direction of a force applied to teeth when the orthodontic appliance is worn by a patient, prior to forming the discontinuous portion on the outer layer of the outer shell.

15. The method according to claim 13, Wherein, the discontinuous portion is configured such that when the orthodontic appliance is worn by a patient, the discontinuous portion deforms by causing a mismatch between the alignment of the patient's teeth and the alignment of teeth defined by the geometry of the orthodontic appliance.

16. The method according to claim 13, Wherein, the discontinuous portion on the outer layer is formed such that the discontinuous portion does not expose the inner layer of the outer shell.

17. The method according to claim 13, Wherein, the discontinuous portion on the outer layer is formed such that the discontinuous portion exposes the inner layer of the outer shell.

18. The method according to claim 13, Wherein, forming the outer shell comprises: forming the inner layer and the outer layer simultaneously.

19. The method according to claim 13, Wherein, forming the outer shell comprises: forming the inner layer and the outer layer sequentially.

20. The method according to claim 13, Wherein, the inner layer is less hard than the outer layer.

21. The method according to claim 13, Wherein, forming the discontinuous portion on the outer layer of the outer shell comprises cutting the outer layer on the inner layer of the outer shell.

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