CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims priority to U.S. Provisional Patent Application No. 62/588,303, filed on 11/17/2017 (“ORTHODONTIC RETAINERS”) and U.S. Provisional Patent Application No. 62/598,454, filed on 12/13/2017 (“ORTHODONTIC RETAINERS”), each of which is herein

incorporated by reference in its entirety.

INCORPORATION BY REFERENCE

[0002] All publications and patent applications mentioned in this specification are herein

incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.

FIELD

[0003] The present application relates to dental retainer devices and methods for preparing dental retainer devices.

BACKGROUND

[0004] Currently patient-specific retainers are often made via thermoforming to a mold made from the patient’s dental anatomy. Typically the mold is made of the patient dental anatomy while the patient is at the doctor’s office. The thermoforming process limits the geometries that can be manufactured for the patient-specific retainer in many cases. Improved methods for making the patient-specific retainers with more complex geometry are desired. The additional geometries that can be employed for the patient-specific retainer allow the manufacture of improved patient-specific retainers. The additional customization can also provide an improved workflow for the doctor treating the specific needs of the patient. Thus, there is a need for improved patient-specific retainers and methods of making and using the same. Described herein are devices and methods that may address these needs.

SUMMARY OF THE DISCLOSURE

[0005] Described herein are dental retainer devices, methods for making dental retainer devices, methods for using dental retainer devices, and methods for preparing patient-specific dental retainer devices.

[0006] Typically, these dental retainer devices are configured to be worn in a patient’s mouth and may generally include: a unitary body formed of a retainer material, the unitary body including different thicknesses, the unitary body defining regions including: an anterior teeth region configured to hold a patient’s anterior teeth within a pocket having lingual, occlusal, and buccal sides; a first posterior teeth region and a second posterior teeth region each configured to hold the patient’s molars in a pocket having lingual, occlusal, and buccal sides; and a palatal region configured to extend between the posterior teeth regions, adjacent to the patient’s palate. The buccal side includes the labial side (e.g., for anterior teeth), as used herein.

[0007] The unitary body may be fabricated as a single or uniform material (e.g., as a monolithic apparatus). Thus, the unitary body may be formed without any joins (e.g. joints) or connections, although it may include regions of different thicknesses; the minimum thicknesses through the uniform body (e.g., from a top surface to a bottom surface) may vary across the device, e.g., by 5% or more (e.g., 7% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 50% or more, etc.).

[0008] The unitary body is typically formed of a retainer material. The retainer material may be any material appropriate to act as a biocompatible retainer for use in a patient’s mouth. For example, the retainer material may be a polymeric material (including plastics), metals, ceramics, etc. Polymeric materials, and in particular those that may be shaped using an additive printing (e.g., 3D printing) and may be formed of a material that resists bending and/or deformation. For example, the unitary body may have a hardness measured by ShoreA durometer of 70 or greater (e.g., 72 or greater, 75 or greater, 77 or greater, 80 or greater, 82 or greater, etc.), or a Shore D durometer of greater than 45, or a Rockwell R durometer of greater than 50. This may be contrasted with dental appliances (including dental retainers), which may typically be softer, and more elastic. For example, the retainer material may comprise nylon.

[0009] The unitary body may be configured to mate with the patient’s upper or lower dental arch. Generally, the unitary body, while a unitary structure, may be observed to have different functional regions, which may have different structural characteristics. These different regions may include an anterior teeth region that is configured to hold a patient’ s anterior teeth within a pocket that may have lingual, occlusal, and/or buccal sides. The anterior teeth region may be customized specifically to mate with a particular patient’s front teeth (e.g., incisors and/or canines). The pocket may refer to a channel, shell, receptacle, compartment, hollow, or cavity. The pocket may define interior walls that conform to one or more of the outer tooth surfaces (e.g., buccal, lingual and/or occlusal surfaces). In some variations, the pocket may be a plurality of connected individual tooth pockets that form a continuous channel, with the different individual pocket regions within the channel configured to fit against a particular tooth.

[0010] The unitary body may also include a first posterior teeth region and/or a second posterior teeth region that are configured to hold the patient’s molars (and in some variations, premolars) in a channel or pocket having one or more of lingual, occlusal, and buccal sides. As with the anterior teeth region, the pocket of the first and second posterior teeth region may refer to a channel, shell, receptacle, compartment, hollow, or cavity, and may define interior walls that conform to one or more of the outer tooth surfaces (e.g., buccal, lingual and/or occlusal surfaces). In some variations, the pocket may be a plurality of connected individual tooth pockets that form a continuous channel, with the different individual pocket regions within the channel configured to fit against a particular tooth. The pockets of the individual regions (sub-regions) may be continuous; for example, in variations having both the first and second posterior teeth region and an anterior teeth region, the pocket of the first posterior teeth region and the pocket of the second posterior teeth region maybe continuous with the pocket of the anterior teeth region.

[0011] The unitary body may also include a palatal region configured to extend between the teeth- receiving cavities (e.g., the posterior teeth region) and adjacent to the patient’s palate. The palatal region may extend and connect to any of the first and second posterior teeth region and an anterior teeth region (e.g., to a buccal side). The palatal region may be configured to be positioned against the palate, or offset from all or a portion of the patient’s palate by some amount (e.g., 0.1 mm or more, between 0.1 mm and 10 mm, 0.2 mm and 5 mm, etc.). Thus, the palatal region may be configured to be adjacent to but not contact a palate of the patient when the patient is wearing the device.

[0012] The outer surface of the unitary body may be shaped to resemble the patient’s teeth, or it may be shaped differently from the patient’ s teeth. In general, the outer surface of the unitary body may be colored and/or patterned (including patterns of one or more of: colors, shapes, text, images, icons, emojis, cartoon characters, pictures, etc.), or it may be transparent or translucent.

[0013] The dental retainer devices described herein may be configured so that one or more of the regions is missing or partial. For example, the dental retainer device may be formed of a unitary body that includes a first posterior teeth region and a second posterior teeth region and a palatal region (but no anterior teeth region, or a partial anterior tooth region comprising just a lingual side). A dental retainer device may be formed of an anterior teeth region, and a palatal region (but no first posterior teeth region and a second posterior teeth region, or a partial first posterior teeth region and partial second posterior teeth region having, e.g., just a lingual side). A dental retainer device may include an anterior teeth region, a palatal region and a partial first posterior teeth region and a partial second posterior teeth region, in which the first and second posterior teeth regions include just lingual and buccal (but not occlusal) sides. Other examples are described herein.

[0014] For example, a dental retainer device configured to be worn in a patient’s mouth may include: a unitary body formed of a retainer material, the unitary body including different thicknesses, the unitary body defining regions including: an anterior teeth region configured to hold anterior teeth within a pocket having lingual, occlusal, and buccal sides; a first posterior teeth region and a second posterior teeth region, each having a lingual surface wherein the first posterior teeth region and the second posterior teeth region are open on an occlusal side, further wherein the lingual surface of the first and second posterior teeth regions are configured to conform to the patient’s molars. The unitary body may further comprise a palatal region extending between the first and second posterior regions and the anterior teeth region, wherein the palatal region is configured to be worn adjacent to the subject’s palate.

[0015] The palatal region may be solid, or it may comprise a plurality of strips extending between the first and second posterior regions. The first and second posterior teeth regions may comprise a buccal surface configured to conform the patient’s molars. The retainer may be solid or it may include one or more pores, openings, gaps, etc. Any of the retainers described herein may be monolithic (e.g., formed of a single material) or may include additional materials. [0016] A dental retainer device configured to be worn in a patient’s mouth may include: a unitary body formed of a retainer material, the unitary body including different thicknesses, the unitary body defining regions including: an anterior teeth region configured to conform to the patient’ s anterior teeth at a lingual side but not on a buccal side; and a first posterior teeth region and a second posterior teeth region, wherein the first and second posterior teeth regions are each configured to hold molars in a pocket having lingual and buccal sides with an opening on an occlusal side. The unitary body may further include a palatal region extending between the first posterior teeth region and the second posterior teeth region, and wherein the palatal region is configured to be adjacent to the patient’s palate when the patient is wearing the device.

[0017] A dental retainer device may be configured to be worn in a patient’s mouth and may include: a unitary body formed of a retainer material, the unitary body including different thicknesses, the unitary body defining regions including: an anterior teeth region configured to conform to the patient’s anterior teeth at a lingual side but not on a buccal side; and a first posterior teeth region and a second posterior teeth region, wherein the first and second posterior teeth regions are each configured to hold molars in a pocket having lingual, buccal and occlusal sides. The unitary body may further comprise a palatal region extending between the first posterior teeth region and the second posterior teeth region, and wherein the palatal region is configured to be adjacent to the patient’s palate when the patient is wearing the device.

[0018] A dental retainer device configured to be worn in a patient’s mouth may include: a unitary body formed of a retainer material, the unitary body including different thicknesses, the unitary body defining regions including: an anterior teeth region configured to hold anterior teeth within a pocket having lingual, occlusal, and buccal sides; a first posterior teeth region and a second posterior teeth region each configured to engage with molars on a lingual side; and a palatal region between the first posterior teeth region, the second posterior teeth region and the anterior teeth region, wherein the palatal region is configured to extend adjacent to the patient’s palate when a patient is wearing the device.

[0019] A dental retainer device configured to be worn in a patient’s mouth may include: a unitary body formed of a retainer material, the unitary body including different thicknesses, the unitary body defining regions including: an anterior teeth region configured to engage anterior teeth on a lingual side and a buccal side but open on an occlusal side; a first posterior teeth region and a second posterior teeth region each configured to hold molars in a between a lingual side and a buccal side, wherein the lingual and buccal sides are configured to conform to the patient’s teeth when the patient is wearing the device.

[0020] Each of the first and second posterior teeth regions may further comprise an occlusal surface extending between the lingual side and the buccal side; further wherein the occlusal surface only partially covers the occlusal surface of the patient’s molars when the patient is wearing the device. Any of these apparatuses may have one or more bridge regions (bridges) between the buccal and lingual portions of the apparatus that are configured to fit into the interproximal areas in order to connect the two sides (e.g. for stiffening) but that have a low profile such that they do not extend beyond the patient’s occlusal surfaces, and are configured not to contact the opposing jaw before the opposing teeth make contact, thus avoiding the tendency for posterior open bite. [0021] The unitary body may further comprise a palatal region extending between the first posterior teeth region and the second posterior teeth region, and wherein the palatal region is configured to be adjacent to the patient’s palate when the patient is wearing the device.

[0022] A dental retainer device configured to be worn in a patient’s mouth may include: a unitary body formed of a retainer material, the unitary body including different thicknesses, the unitary body defining regions including: an anterior teeth region configured to hold anterior teeth within a pocket having lingual and buccal sides, the anterior teeth region including an opening on an occlusal side; a first posterior teeth region and a second posterior teeth region each configured to hold molars in a pocket having lingual, occlusal, and buccal sides, wherein the first posterior teeth region and second posterior teeth region include openings on an occlusal side; and a palatal region configured to extend adjacent to a palate between the first posterior teeth region and the second posterior teeth region and the anterior teeth region.

[0023] A dental retainer device configured to be worn in a patient’s mouth may include: a unitary body formed of a retainer material, the unitary body including different thicknesses, the unitary body defining regions including: an anterior teeth region configured to hold anterior teeth within a pocket having lingual, occlusal, and buccal sides; a first posterior teeth region and a second posterior teeth region each configured to hold molars in a pocket having lingual, occlusal, and buccal sides; and a palatal region extending between the first posterior teeth region and the second posterior teeth region and configured to be adjacent to the patient’s palate when the device is worn by the patient, wherein the palatal region includes one or more openings between the anterior teeth region and the palatal region.

[0024] In general, the unitary body may include a protrusion, tab, hook, or other attachment structure configured to attach a rubber band. For example, the unitary body may include a slot configured to attach a rubber band.

[0025] The unitary body may include a mandibular advancement feature. For example, a mandibular advancement feature may be a block, ramp, or other surface shape extending from of the unitary body which may engage with another surface feature (e.g., block, ramp, etc.) on an opposite jaw (e.g., on a second unitary body worn on the opposite jaw).

[0026] In any of the apparatuses described herein, the unitary body may include a gingival support region. For example, the unitary body may include a region extending down to and at least partially over the gingiva. In some variations the gingival support region extends apart from the gingiva by some amount (e.g., between 0.1 mm and 10 mm, between 0.1 mm and 5 mm, between 0.1 mm and 3 mm, etc.).

[0027] In any of the apparatuses described herein, the unitary body may include a thickened base region. For example, the region near the gingiva may be thicker (e.g., >5%, >10%, >15%, >20%, > 25%, >30%, >35%, >40%, >45%, >50%, etc. thicker) than the region(s) above this base region.

[0028] Any of the unitary bodies described herein may include a plurality of ridges. Alternatively or additionally, any of these apparatuses may include a bias (e.g., a bias element, spring, spring element, etc.) attached to or integral with the unitary body. A biasing element may be a spring (e.g., leaf spring, etc.) or other structure configured to apply a force. [0029] The palatal region may be configured to engage with a palate of the patient when the patient is wearing the device. Any of these apparatuses may include an interproximal support feature, which may include one or more open spaces, and/or a second material that is less rigid than the retainer material (e.g. has a durometer that is less than the durometer of the retainer material). For example, the apparatus may include an interproximal support feature having a rigidity that is less rigid than the unitary body formed of the retainer material.

[0030] Also described herein are methods of making patient-specific dental retainer apparatus (e.g., device, system, etc.). For example a method of making a patient-specific dental retainer device may include: receiving a scan of a patient’s dental arch, including a plurality of teeth; and manufacturing the patient-specific retainer based on the scan by additive manufacturing, wherein the patient-specific retainer is any of the retainers described herein.

[0031] Also described herein are methods of retaining the position of a patient’s teeth following an orthodontic treatment. For example a method of retaining the position of a patient’s teeth following an orthodontic treatment may include: wearing a series of aligners configured to progressively move the patient’s teeth; and wearing a retainers such as any of the retainers described herein (which are configured specifically to fit the patient’s teeth, and particularly the final position of the patient’s teeth following treatment with the series of aligners).

[0032] Also described herein are methods of planning a patient-specific retainer device and apparatuses (including software, firmware, hardware, etc.) for implementing these methods. For example a method of planning a patient-specific retainer device may include: receiving a three-dimensional representation of a patient dental anatomy; displaying at least a portion of the three-dimensional representation of the patient dental anatomy; providing one or more options associated with retainer configurations, the one or more options including a palatal configuration, an anterior teeth coverage configuration, and a posterior teeth coverage configuration; providing one or more add-on options for the retainer; receiving responses or instructions to the one or more options and one or more add-on options; and preparing a model of a custom retainer based on the patient dental anatomy and the responses or instructions to the one or more options and one or more add-on options.

[0033] The method may be interactive. For example, the designer (e.g., dental professional) may be presented with an interactive display (e.g., 3D model) of the patient’s oral cavity including the dental arch (one or more of: teeth, gingiva, palate, etc. for upper arch and/or one or more of teeth, gingiva, etc. for the lower arch) and/or a modified/projected display of the final position of the patient’s teeth and/or palate. The designer may then select among various features for the retainer, including which regions (anterior teeth region, first and second posterior teeth regions, palatal regions, etc.) and more specifically, various shapes and configurations for these regions, to include. The regions may be customized to the 3D model of the patient’ s oral cavity.

[0034] Any of these methods may include: displaying an image of the custom retainer overlying the three-dimensional representation of the patient dental anatomy. [0035] The anterior teeth coverage configuration and the posterior teeth coverage configuration may include options for buccal coverage, lingual coverage, and occlusal coverage for the anterior teeth and the posterior teeth.

[0036] These methods (and an apparatus implementing them) may include add-on options for the retainer include one or more of: a protrusion, tab, hook, or other attachment structure configured to attach a rubber band, a slot configured to attach a rubber band, a mandibular advancement feature, an interproximal support feature, a ramp, a gingival support region, a thickened base region, and a plurality of ridges.

[0037] In particular, described herein are method of forming a retainer, the method comprising: gathering a three-dimensional (3D) model of a patient’s dentition; translating a target arrangement of the patient’s teeth from the 3D model of the patient’s dentition into a two-dimensional (2D) height map of the patient’s dentition; defining a boundary of a retainer configured to fit onto the patient’s dentition; building a 2D mesh of an upper surface of the patient’s dentition from the 2D height map; converting the 2D mesh of the upper surface of the patient’s dentition into a 3D mesh of the upper surface of the patient’s dentition; forming a bottom surface of a digital model of the retainer using the 3D mesh of the upper surface; forming a top surface of the digital model of the retainer having different thicknesses between the top surface and bottom surfaces of the digital model of the retainer; and exporting the digital model of the retainer for 3D printing.

[0038] For example, a method of forming a retainer may include: gathering a three-dimensional (3D) model of a patient’s dentition and a target arrangement of the patient’s teeth; translating the target arrangement of the patient’s teeth in from the 3D model of the patient’s dentition into a two-dimensional (2D) height map of the patient’s dentition; defining a boundary of a retainer configured to fit onto the patient’s dentition when the patient’s teeth are in the target arrangement; building a 2D mesh of an upper surface of the patient’s dentition from the 2D height map using the boundary; converting the 2D mesh of the upper surface of the patient’s dentition into a 3D mesh of the upper surface of the patient’s dentition; forming a bottom surface of a digital model of the retainer using the 3D mesh of the upper surface;

forming a top surface of the digital model of the retainer at different thicknesses between the top surface and bottom surface of the digital model of the retainer; adjusting one or more of the smoothness of the top surface of the distal model of the retainer and the thickness between the top surface and the bottom surface of the digital model of the retainer; and exporting the digital model of the retainer for 3D printing.

[0039] Also described herein are systems configured to perform any of the methods described herein. In general, these method may include one or more processors and a memory coupled to the one or more processors that is configured to store instructions that, when executed by the one or more processors perform the method. For example, described herein are systems comprising: one or more processors; a memory coupled to the one or more processors, the memory configured to store instructions, that, when executed by the one or more processors, perform a computer-implemented method comprising: gathering a three-dimensional (3D) model of a patient’s dentition; translating a target arrangement of the patient’s teeth from the 3D model of the patient’s dentition into a two-dimensional (2D) height map of the patient’s dentition; defining a boundary of a retainer configured to fit onto the patient’s dentition; building a 2D mesh of an upper surface of the patient’s dentition from the 2D height map; converting the 2D mesh of the upper surface of the patient’s dentition into a 3D mesh of the upper surface of the patient’s dentition; forming a bottom surface of a digital model of the retainer using the 3D mesh of the upper surface;

forming a top surface of the digital model of the retainer having different thicknesses between the top surface and bottom surfaces of the digital model of the retainer; and exporting the digital model of the retainer for 3D printing.

[0040] For example a system (e.g., for forming or designing a retainer) may include: one or more processors; a memory coupled to the one or more processors, the memory configured to store instructions, that, when executed by the one or more processors, perform a computer-implemented method comprising: gathering a three-dimensional (3D) model of a patient’s dentition and a target arrangement of the patient’s teeth; translating the target arrangement of the patient’s teeth in from the 3D model of the patient’s dentition into a two-dimensional (2D) height map of the patient’s dentition; defining a boundary of a retainer configured to fit onto the patient’ s dentition when the patient’ s teeth are in the target

arrangement; building a 2D mesh of an upper surface of the patient’s dentition from the 2D height map using the boundary; converting the 2D mesh of the upper surface of the patient’s dentition into a 3D mesh of the upper surface of the patient’s dentition; forming a bottom surface of a digital model of the retainer using the 3D mesh of the upper surface; forming a top surface of the digital model of the retainer at different thicknesses between the top surface and bottom surface of the digital model of the retainer; adjusting one or more of the smoothness of the top surface of the distal model of the retainer and the thickness between the top surface and the bottom surface of the digital model of the retainer; and exporting the digital model of the retainer for 3D printing.

[0041] Any of these methods and systems may include smooth the edges between the bottom surface and the top surface of the digital model of the retainer. Any of these methods and systems may be configured to add an identifying code on one or more surfaces of the digital model of the retainer (e.g., an alphanumeric code, QR code, etc.). Any of these methods and systems may be configured to build a matrix mesh of the digital model of the retainer, wherein exporting the digital model of the retainer comprises converting the matrix mesh into a stereolithographic (STL) file format.

[0042] In any of these methods and systems, building the 2D mesh of the upper surface of the patient’s dentition may comprise building the 2D mesh from the 2D height map using the boundary. Building the 2D mesh of the upper surface of the patient’s dentition from the 2D height map may include triangulating the 2D height map. Forming the bottom surface of the digital model of the retainer using the 3D mesh of the upper surface may comprise smoothing the bottom surface to remove any sharp corners. For example, forming the bottom surface of the digital model of the retainer using the 3D mesh of the upper surface may comprise smoothing the bottom surface by setting starting points forming the bottom surface that are initially on the 3D mesh of the upper surface and dilating and eroding the starting points at a minimum distance from the 3D mesh of the upper surface. [0043] In any of these methods and systems, gathering the three-dimensional (3D) model of a patient’s dentition may include gathering a digital scan of the patient’s jaw and a treatment file including the target arrangement of teeth in the patient’s jaw. In some variations, gathering the three-dimensional (3D) model of a patient’s dentition comprises gathering a digital scan of the patient’s jaw with the teeth in the target arrangement.

[0044] Translating the target arrangement of the patient’s teeth from the 3D model of the patient’s dentition into the two-dimensional (2D) height map of the patient’s dentition may comprise rasterizing the 3D model of the patient’ s dentition as 2D height map points.

[0045] Any of these methods and systems may also include adding a filler shape so that the filler shape is present on the 3D mesh of the upper surface and reduces spaces between the teeth.

[0046] Further, any of these methods and apparatuses may include manufacturing the patient- specific retainer (e.g., by 3D printing the retainer from the digital model of the retainer).

[0047] Any of the dental retainer devices described herein may include any of: a unitary body formed of a retainer material, the unitary body having different thicknesses along its length, the unitary body defining multiple regions including: an anterior teeth region configured to hold a patient’s anterior teeth within a pocket having lingual and occlusal sides; a first posterior teeth region and a second posterior teeth region each configured to hold the patient’s molars in a pocket having lingual and occlusal sides; and a palatal region configured to extend between the first and second posterior teeth regions and adjacent to the patient’s palate, wherein the palatal region is thicker than the occlusal side of the first and second posterior teeth regions; wherein a top surface of the palatal region is smoother than a bottom surface of the palatal region, further wherein the bottom surface is configured to be worn adjacent to the patient’s palate.

[0048] For example, a dental retainer device may include: a unitary body formed of a retainer material, the unitary body having different thicknesses along its length, the unitary body defining multiple regions including: an anterior teeth region configured to hold a patient’s anterior teeth within a pocket having lingual and occlusal sides; a first posterior teeth region and a second posterior teeth region each configured to hold the patient’s molars in a pocket having lingual and occlusal sides; a palatal region configured to extend between the first and second posterior teeth regions and adjacent to the patient’s palate, wherein the palatal region is thicker than the occlusal side of the first and second posterior teeth regions, and the thickness of the palatal region increase between the first and second posterior teeth regions; wherein a top surface of the palatal region is smoother than a bottom surface of the palatal region, further wherein the bottom surface is configured to be worn adjacent to the patient’s palate; and an identifying code on one or more of: the bottom surface of the palatal region or a posterior edge of the palatal region.

[0049] Any of these devices may include an identifying code on one or more of: the bottom surface of the palatal region or a posterior edge of the palatal region.

[0050] The thickness of the palatal region may increase between the first and second posterior teeth regions. The palatal region may comprise a plurality of strips extending between the first and second posterior regions. The first and second posterior teeth regions may each comprise a buccal surface configured to conform the patient’s molars. The first and second posterior teeth regions may each comprises a buccal surface configured to extend at least 2 mm over the patient’ s gingiva when worn. The unitary body may include an attachment structure configured to attach an elastic, a slot configured to attach an elastic, a mandibular advancement feature (e.g., a ramp surface extending from of the unitary body), a gingival support region, a plurality of ridges, a bias element attached to or integral with the unitary body, and/or an interproximal support feature. The interproximal support feature may comprise one or more open spaces and/or a second material, wherein the second material is less rigid than the retainer material. The interproximal support feature may have a rigidity that is less rigid than the unitary body.

[0051] In any of these variations, as mentioned, the retainer material may have a Young’s modulus of between about 0.01 and 5 GPa. In some variations, the retainer material comprises nylon.

[0052] As mentioned, also described herein are methods of designing a patient-specific retainer device, the method comprising: receiving a three-dimensional (3D) representation of a patient dental anatomy and a treatment plan including an initial arrangement of the patient’s teeth and a final arrangement for the patient’s teeth; displaying at least a portion of the three-dimensional representation of the patient dental anatomy in one or more stages of the treatment plan including the initial arrangement and the final arrangement; providing one or more options associated with retainer configurations, the one or more options including a palatal configuration, an anterior teeth coverage configuration, and a posterior teeth coverage configuration; providing one or more add-on options for the retainer; receiving selections from a user for the one or more options and one or more add-on options; preparing a model of the patient-specific retainer based on the patient dental anatomy and the received selections to the one or more options and one or more add-on options; and interactively displaying the model of the patient- specific retainer so that the model and display of the model are updated as the user modifies the selections of the one or more options and one or more add-on options.

[0053] For example, a method of designing a patient-specific retainer device may include: receiving a three-dimensional (3D) representation of a patient dental anatomy including a final arrangement for the patient’s teeth; displaying at least a portion of the three-dimensional representation of the patient dental anatomy in the final arrangement for the patient’s teeth; providing two or more selectable options associated with retainer configurations, the selectable options including: a palatal configuration, an anterior teeth coverage configuration, and a posterior teeth coverage configuration; providing one or more selectable add-on options for the retainer, the selectable add-on options including: a protrusion, a tab, a hook, an attachment structure configured to attach a rubber band, a slot configured to attach a rubber band, a mandibular advancement feature, an interproximal support feature, a ramp, a gingival support region, a thickened base region, and a plurality of ridges; receiving selections from a user for the one or more options and one or more add-on options (though in some variation no add-on options may be chosen); preparing a model of the patient-specific retainer based on the patient dental anatomy and the received selections to the one or more options and one or more add-on options; and interactively displaying the model of the patient-specific retainer so that the model and display of the model are updated as the user modifies the selections of the one or more options and one or more add-on options.

[0054] These methods may include displaying an image of the patient-specific retainer overlying the three-dimensional representation of the patient dental anatomy. The anterior teeth coverage configuration and the posterior teeth coverage configuration may include options for buccal coverage, lingual coverage, and occlusal coverage for the anterior teeth and the posterior teeth. The add-on options for the retainer may include one or more of: a protrusion, tab, hook, or other attachment structure configured to attach a rubber band, a slot configured to attach a rubber band, a mandibular advancement feature, an

interproximal support feature, a ramp, a gingival support region, a thickened base region, and a plurality of ridges.

[0055] Any of these methods may include interactively modifying a display of the patient-specific retainer as the user selects the one or more options and the one or more add-on options.

[0056] These methods may include receiving, from the user, a command to change the stage of the treatment plan being displayed as the at least a portion of the three-dimensional representation of the patient dental anatomy.

[0057] Any of these methods may include receiving, from the user, a command to rotate the at least the portion of the three-dimensional representation of the patient dental anatomy and/or to zoom in or out. Any of these method may include exporting the model of the patient-specific retainer as a digital file for fabrication.

[0058] Any of these methods and systems may include fabricating the patient-specific retainer from the model of the patient-specific retainer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The novel features of the invention are set forth with particularity in the claims that follow.

A better understanding of the features and advantages of the present 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 of which:

[0060] FIGS. 1A-1D illustrate top, top perspective, side and front views, respectively, of a retainer device configured to be worn in a patient’s mouth.

[0061] FIGS. 2A-2D illustrate top, top perspective, side and front views, respectively, of a retainer device configured to be worn in a patient’s mouth, including an anterior teeth region, a first posterior teeth region and a second posterior teeth region, wherein the first and second posterior teeth regions do not have occlusal surfaces.

[0062] FIGS. 3A-3D illustrate top, top perspective, side and front views, respectively, of a retainer device configured to be worn in a patient’s mouth, including an anterior teeth region having just a lingual portion, a first posterior teeth region and a second posterior teeth region, wherein the first and second posterior teeth regions do not have occlusal surfaces.

[0063] FIGS. 4A-4D illustrate top, top perspective, side and front views, respectively, of a retainer device configured to be worn in a patient’s mouth, including an anterior teeth region, a first posterior teeth region and a second posterior teeth region, wherein the first and second posterior teeth regions have just lingual sides.

[0064] FIGS. 5A-5D illustrate top, top perspective, side and front views, respectively, of a retainer device configured to be worn in a patient’s mouth including an anterior teeth region, a first posterior teeth region and a second posterior teeth region, wherein the first and second posterior teeth regions have just lingual sides, and a palatal region formed of support strips extending between the first and second posterior teeth regions.

[0065] FIGS. 6A-6D illustrate top, top perspective, side and front views, respectively, of a retainer device configured to be worn in a patient’s mouth including an anterior teeth region, and a palatal region.

[0066] FIGS. 7A-7D illustrate top, top perspective, side and front views, respectively, of a retainer device configured to be worn in a patient’s mouth including an anterior teeth region having just a lingual side that extends and over the gingiva, a first posterior teeth region and a second posterior teeth region.

[0067] FIGS. 8A-8D illustrate top, top perspective, side and front views, respectively, of a retainer device configured to be worn in a patient’s mouth including an anterior teeth region having just partial buccal and lingual sides, a first posterior teeth region and a second posterior teeth region, wherein the occlusal surface of the first and second posterior teeth regions is partially removed.

[0068] FIGS. 9A-9D illustrate top, top perspective, side and front views, respectively, of a retainer device configured to be worn in a patient’s mouth, similar to the device shown in FIG. 8A-8D, but also including a palatal region.

[0069] FIGS. 10A-10D illustrate top, top perspective, side and front views, respectively, of a retainer device configured to be worn in a patient’s mouth including a first posterior teeth region and a second posterior teeth region and a palatal region.

[0070] FIGS. 11 A-l 1D illustrate top, top perspective, side and front views, respectively, of a retainer device configured to be worn in a patient’s mouth including an anterior teeth region, a first posterior teeth region and a second posterior teeth region, and a palatal region including an anterior window before the anterior teeth region.

[0071] FIGS. 12A-12D illustrate top, top perspective, side and front views, respectively, of a retainer device configured to be worn in a patient’s mouth including an anterior teeth region, and a first posterior teeth region and a second posterior teeth region, as well as a mandibular advancement feature.

[0072] FIGS. 13A-13D illustrate top, top perspective, side and front views, respectively, of a retainer device configured to be worn in a patient’s mouth, including a mandibular advancement feature.

[0073] FIGS. 14A-14D illustrate top, top perspective, side and front views, respectively, of a retainer device configured to be worn in a patient’s mouth, also including a solid occlusal mandibular advancement feature.

[0074] FIGS. 15A-15D illustrate top, top perspective, side and front views, respectively, of a retainer device configured to be worn in a patient’s mouth.

[0075] FIG. 16 illustrates a retainer having a gingival-covering region on the lingual sides. [0076] FIGS. 17A-17B illustrate retainers having features such as a universal connectors (for connecting one or more additional element), thicker regions and/or stiffening members.

[0077] FIGS. 18A-18B illustrate additional embodiments of retainers having additional features such as ridges (e.g., press ridges), and/or variable thicknesses.

[0078] FIGS. 19A-19B illustrate additional examples of retainers having voids or openings through the unitary body to increase flexibility.

[0079] FIG. 20 illustrates day and night retainers for a patient.

[0080] FIGS. 21A-21B illustrates retainers including a buccal bar.

[0081] FIG. 22 illustrates a method 2200 for planning a patient-specific retainer device.

[0082] FIG. 23 illustrates an example of a method of designing and building a retainer or multiple retainers as described herein.

[0083] FIGS. 24A-24C illustrate examples of retainers. In FIG. 24A, the retainer includes a cut-out (partial) palatal region as well as a full anterior region and a pair of partial posterior regions. FIG. 24B is similar to FIG. 24A, but includes a full palatal region. FIG. 24C is similar to FIG. 24B but includes additional lateral palatal regions, partially up to the lingual sides of the teeth.

[0084] FIG. 25 shows a retainer similar to the retainer of FIG. 24C but includes a central cut-our region within the palatal region.

[0085] FIG. 26 is another example of a retainer including posterior tooth-retaining regions, and a palatal region, but missing the anterior tooth-regaining region.

[0086] FIG. 27 is another example of a retainer having an anterior tooth-retaining region and a pair of partial posterior tooth retaining regions missing occlusal portions over the majority of the tooth- retaining regions.

[0087] FIG. 28 is an example of a user interface for an apparatus for designing a retainer as described herein.

[0088] FIGS. 29A-29D illustrate another example of a retainer as described herein in different views.

[0089] FIG. 30A is a flow diagram of an exemplary process for designing and building a retainer as described herein.

[0090] FIG. 30B illustrates one example of a method of designing a retainer.

[0091] FIG. 30C is a diagram illustrating one system for designing and/or fabricating a retainer as described herein.

[0092] FIGS. 31 A and 31B illustrate a method of making a retainer including a space for an erupting teeth and a retainer including a space for an erupting teeth, respectively.

[0093] FIG. 32 is an example of a retainer including eruption guidance features that may be used to guide erupting permanent teeth.

[0094] FIG. 33 A is an example of a 3D model of a patient’s dentition (teeth, gingiva and palate region) in a target configuration. [0095] FIG. 33B is an example of a retainer as described herein.

[0096] FIGS. 34A-34D illustrate an overview of a method of forming a retainer.

[0097] FIG. 35 is an example of a portion of a patient’s dentition showing reference mapping regions.

[0098] FIGS. 36A-36C illustrate additional mapping directions of a patient’s dentition that may be used in forming a retainer.

[0099] FIGS. 37A-37B show the scan axis curve and occlusal curve of one example of a 3D model of a patient’s dentition in a final configuration.

[0100] FIG. 38 is an example of a scan axis base and regions of one example of a model of a patient’s dentition in a final configuration.

[0101] FIG. 39 shows a scan curve of a model of one example of a patient’s dentition in a final configuration.

[0102] FIG. 40 illustrates a scan surface of a model of a patient’s dentition in a final configuration.

[0103] FIG. 41 illustrates a method of using a scan curve to map a 3D model in one example of a patient’s dentition in a final configuration to a 2D height map.

[0104] FIGS. 42A-42C graphically illustrate one example of a method of unwarping and mapping a 3D to 2D height map.

[0105] FIG. 43 illustrates one example of surface that may be used to build a retainer (e.g., jaw surfaces, including crown, gingiva, palate, etc.)

[0106] FIG. 44 illustrates one example of rescanning and rasterizing triangles from a 3D mesh to 2D triangles to create a uniform point cloud and nice mesh.

[0107] FIGS. 45A-45B show one example of a method of adjusting a model of the patient’s dentition to correct for narrow regions (e.g., long, thin and/or sharp regions) when using the model of the patient’s dentition as the template for forming a retainer.

[0108] FIGS. 46A-46C illustrate an example of a method of adjusting a model of the patient’s dentition to correct for narrow regions (e.g., long, thin and/or sharp regions) when using the model of the patient’s dentition as the template for forming a retainer, including the use of a filler.

[0109] FIGS. 47A-47B illustrate one example of using boundaries to form a mesh from a point cloud of one example of a model of a patient’s dentition.

[0110] FIG. 48 is an example of determining boundaries in a model of a patient’s dentition to form the retainer, having a small U-shaped posterior boundary.

[0111] FIG. 49 is an example of determining boundaries in a model of a patient’s dentition to form the retainer, having a large U-shaped posterior boundary.

[0112] FIGS. 50A-50B illustrate one example of a method of removing problem regions in a boundary (e.g., a small loop) when determining a boundary as part of a process or apparatus for forming a retainer. [0113] FIGS. 51A-51C illustrate one example of building a mesh from a point cloud as described herein in the process of forming a retainer.

[0114] FIGS. 52A-52B illustrate one example of a method of smoothing the bottom surface of an aligner when forming a retainer as described herein.

[0115] FIG. 53 shows one example of creating clearance between the retainer being designed and a palate surface as described herein.

[0116] FIGS. 54A-54B illustrate one example forming a top layer and adjusting the thickness of a retainer being designed.

[0117] FIGS. 55A-55B illustrate one example of a thickness transition curve that may be used to adjust the thickness of a retainer being designed.

[0118] FIGS. 56A-56B illustrate a method of adjusting or correcting the top surface smoothness of a retainer being designed as described herein.

[0119] FIGS. 57A-57B illustrate one example of smoothing the outer edges of a retainer being designed (an unsmoothed distal end face is shown in FIG. 57A, the same region shown as smoothed is in FIG. 57B).

[0120] FIGS. 58A-58B illustrate a bottom surface of a retainer that includes an identifier (e.g., tag string) as either an engraved identifier, in FIG. 58 A, or an embossed identifier, in FIG. 5B.

DETAILED DESCRIPTION

[0121] Dental retainer devices, methods for making dental retainer devices, methods for using dental retainer devices, and methods for preparing patient-specific dental retainer devices are provided herein. The dental retainer devices can be custom made based on the patient’ s specific dental anatomy and/or the treatment plan developed by the patient’s doctor. The dental retainer devices can be manufactured using additive manufacturing techniques, such as three dimensional printing. The use of three-dimensional printing allows for many customization options and configurations that cannot be made using in-office dental molding techniques. The improved customization allows for additional flexibility for treating each patient’s unique dental anatomy.

[0122] The dental retainer devices can include custom coverage for each of the posterior, anterior, and palatal regions of the patient dental anatomy. The use of additive manufacturing allows for additional customization with material selection versus thermoforming and other conventional techniques. For example, the material for the retainer can be specifically selected based on the desired physical characteristics and properties based on the patient specific treatment plan.

[0123] In some embodiments the dental retainer devices include a unitary body formed of a retainer material with different thicknesses. The unitary body can include a variety of different geometries and configurations as described herein. The unitary body can also define different regions as described herein.

[0124] In some embodiments the unitary body can define regions including: an anterior teeth region configured to hold a patient’s anterior teeth within a pocket having lingual, occlusal, and buccal sides; a first posterior teeth region and a second posterior teeth region each configured to hold the patient’s molars in a pocket having lingual, occlusal, and buccal sides; and a palatal region configured to extend between the adjacent to the patient’s palate.

[0125] In some embodiments the unitary body can define regions including: an anterior teeth region configured to hold anterior teeth within a pocket having lingual, occlusal, and buccal sides along with a first posterior teeth region and a second posterior teeth region, each having a lingual surface with the first posterior teeth region and the second posterior teeth region are open on an occlusal side. The lingual surface of the first and second posterior teeth regions can be configured to conform to the patient’ s molars. In some aspects the unitary body can also include a palatal region extending between the first and second posterior regions and the anterior teeth region. The palatal region can be configured to be worn adjacent to the subject’s palate. In some examples the palatal region can include a plurality of strips extending between the first and second posterior regions. The first and second posterior teeth regions can each include a buccal surface configured to conform the patient’s molars.

[0126] In some embodiments the unitary body can define several different regions including an anterior teeth region configured to conform to the patient’s anterior teeth at a lingual side but not on a buccal side and a first posterior teeth region and a second posterior teeth region. The first and second posterior teeth regions can each be configured to hold molars in a pocket having lingual and buccal sides with an opening on an occlusal side. In some aspects the unitary body can include a palatal region extending between the first posterior teeth region and the second posterior teeth region. The palatal region can be configured to be adjacent to the patient’s palate when the patient is wearing the device.

[0127] In some embodiments the unitary body can define several different regions including an anterior teeth region configured to conform to the patient’s anterior teeth at a lingual side but not on a buccal side and a first posterior teeth region and a second posterior teeth region. The first and second posterior teeth regions can each configured to hold molars in a pocket having lingual, buccal and occlusal sides. In some aspects the unitary body includes a palatal region extending between the first posterior teeth region and the second posterior teeth region. The palatal region can be configured to be adjacent to the patient’s palate when the patient is wearing the device.

[0128] In some embodiments the unitary body can define several different regions including an anterior teeth region configured to hold anterior teeth within a pocket having lingual, occlusal, and buccal sides; a first posterior teeth region and a second posterior teeth region each configured to engage with molars on a lingual side; and a palatal region. The palatal region can extend between the first posterior teeth region, the second posterior teeth region and the anterior teeth region. The palatal region can also be configured to extend adjacent to the patient’s palate when a patient is wearing the device.

[0129] In some embodiments the unitary body can define several different regions including an anterior teeth region configured to engage anterior teeth on a lingual side and a buccal side but open on an occlusal side and a first posterior teeth region and a second posterior teeth region each configured to hold molars in a between a lingual side and a buccal side. The lingual and buccal sides can be configured to conform to the patient’s teeth when the patient is wearing the device. In some aspects each of the first and second posterior teeth regions also include an occlusal surface extending between the lingual side and the buccal side. In some cases the occlusal surface only partially covers the occlusal surface of the patient’s molars when the patient is wearing the device. In some aspects the unitary body also includes a palatal region extending between the first posterior teeth region and the second posterior teeth region. In some aspects the palatal region is configured to be adjacent to the patient’s palate when the patient is wearing the device.

[0130] In some embodiments the unitary body can define several different regions including an anterior teeth region configured to hold anterior teeth within a pocket having lingual and buccal sides with the anterior teeth region including an opening on an occlusal side; a first posterior teeth region and a second posterior teeth region each configured to hold molars in a pocket having lingual, occlusal, and buccal sides with the first posterior teeth region and second posterior teeth region include openings on an occlusal side; and a palatal region configured to extend adjacent to a palate between the first posterior teeth region and the second posterior teeth region and the anterior teeth region.

[0131] In some embodiments the unitary body can define several different regions including an anterior teeth region configured to hold anterior teeth within a pocket having lingual, occlusal, and buccal sides; a first posterior teeth region and a second posterior teeth region each configured to hold molars in a pocket having lingual, occlusal, and buccal sides; and a palatal region extending between the first posterior teeth region and the second posterior teeth region and configured to be adjacent to the patient’s palate when the device is worn by the patient. The palatal region can include one or more openings between the anterior teeth region and the palatal region.

[0132] In any of the embodiments described herein the unitary body can include a protrusion, tab, hook, or other attachment structure configured to attach an elastic bias (e.g., a rubber band, etc.).

[0133] In any of the embodiments described herein the unitary body can include a slot configured to attach a rubber band.

[0134] In any of the embodiments described herein the unitary body can include a mandibular advancement feature. The mandibular advancement feature can include a ramp surface extending from the unitary body.

[0135] Any of the apparatuses described herein may be configured to have a non-uniform thickness. Specifically, the thickness of the retainer apparatus may be thinner in the occlusal regions compared to the slides (lingual and/or buccal). In some variations the thickness may be correlated with the teeth, e.g., it may be thinner in more posterior regions (molars, pre-molars) and thicker more anteriorly (canines, bicuspids, etc.); alternatively the apparatus may be thicker in more posterior regions (molars, pre-molars) and thinner more anteriorly (canines, bicuspids, etc.). In some variations, the lateral extend of the retainer may extend over the buccal side of the teeth and over the patient’s gingiva; alternatively or additionally, the lingual side may extend over the lingual side of the teeth and over the gingiva. The region over the gingiva may be configured not to touch the normal (e.g., non-inflamed) gingiva, but may be angled away from the patient’s gingiva. [0136] In any of the embodiments described herein the unitary body can include a gingival support region.

[0137] In any of the embodiments described herein the unitary body can include a thickened base region.

[0138] In any of the embodiments described herein the unitary body can include a plurality of ridges.

[0139] In any of the embodiments described herein the unitary body can include a non-transparent color and/or a pattern of colors.

[0140] In any of the embodiments described herein the dental retainer can further include a bias element attached to or integral with the unitary body.

[0141] In any of the embodiments described herein the palatal region can be configured to be adjacent to but not contact a palate of the patient when the patient is wearing the device.

[0142] In any of the embodiments described herein the palatal region can be configured to engage with a palate of the patient when the patient is wearing the device.

[0143] In any of the embodiments described herein the retainer can include an interproximal support feature. The interproximal support feature can provide additional support to the teeth to prevent relapse.

In one aspect the interproximal support feature includes one or more open spaces. In some examples the interproximal support feature includes a second material where the second material is less rigid than the retainer material. In some cases the interproximal support feature has a rigidity that is less rigid than the unitary body formed of the retainer material.

[0144] In any of the embodiments described herein, the retainer material can have a Young’s modulus that is relatively“stiff’ (e.g., between about 0.01 and 5 GPa). Further, the hardness of the retainer material may be, e.g., between 60A to 85 D; the apparatus may have an ultimate tensile strength greater than 5000 psi, and/or an elongation at break greater than 200%. In one example the retainer material can be nylon.

[0145] Methods are also provided herein for making a patient-specific dental retainer device. The methods can include receiving a scan of a patient’ s dental arch that includes a plurality of teeth and manufacturing the patient-specific retainer based on the scan by additive manufacturing. The patient- specific retainer can be any of the retainers described herein. In one some cases additive manufacturing includes 3D printing.

[0146] In some embodiments methods of retaining a position of a patient’s teeth following an orthodontic treatment are provided. The methods can include wearing a series of aligners configured to progressively move the patient’s teeth and wearing any of the retainers described herein.

[0147] In some embodiments methods of planning a patient-specific retainer device are provided. The methods can include receiving a three-dimensional representation of a patient dental anatomy, displaying at least a portion of the three-dimensional representation of the patient dental anatomy, providing one or more options associated with retainer configurations, the one or more options including a palatal configuration, an anterior teeth coverage configuration, and a posterior teeth coverage configuration, providing one or more add-on options for the retainer, receiving responses or instructions to the one or more options and one or more add-on options, and preparing a model of a custom retainer based on the patient dental anatomy and the responses or instructions to the one or more options and one or more add-on options. The methods can further include displaying an image of the custom retainer overlying the three-dimensional representation of the patient dental anatomy. In some cases the anterior teeth coverage configuration and the posterior teeth coverage configuration include options for buccal coverage, lingual coverage, and occlusal coverage for the anterior teeth and the posterior teeth. In some aspects the add-on options for the retainer include one or more of: a protrusion, tab, hook, or other attachment structure configured to attach a rubber band, a slot configured to attach a rubber band, a mandibular advancement feature, a ramp, an interproximal support feature, a gingival support region, a thickened base region, and a plurality of ridges. In some embodiments the custom retainer can be any of the retainers described herein.

[0148] A number of modifications can be made to the retainers described herein. In some embodiments any of the retainers described herein can have a reduced thickness on the occlusal surface to help occlusal settling and/or prevent the development of an open bite.

[0149] In some embodiments any of the retainers described herein can include a hollow portion or a window on the buccal surface to reduce coverage and increase retainer aesthetics.

[0150] In some embodiments any of the retainers described herein can include added precision hooks and button cutouts. The added precision hooks and button cutouts can be designed based on the patient specific dental anatomy and made using additive manufacturing.

[0151] In some embodiments any of the retainers described herein can add one or more sensors or chips that are configured to track one or more of the following: patient compliance (e.g., the length of time the apparatus is worn), GPS, health, one or more biomarkers, etc.

[0152] In some embodiments any of the retainers described herein can be manufactured from an eco- friendly and dissolvable material.

[0153] In some embodiments any of the retainers described herein can be configured for use as a 24- hour mouth guard and/or for use during sports activities.

[0154] In some embodiments any of the retainers described herein can be made from a dishwasher safe material to facilitate cleaning.

[0155] In some embodiments any of the retainers described herein can have a tongue retaining features to aid with habit training.

[0156] In some embodiments any of the retainers described herein can be configured to be contacted during tooth brushing and related dental hygiene procedures.

[0157] In some embodiments any of the retainers described herein can include a grinding detector that can provide an indication of the patients grinding behavior. For example color patches can be embedded in the retainer and become visible as the retainer wears down during grinding. The patches can be shaped so the size of the visible portion of the patch indicates the level of wear.

[0158] FIGS. 1 A-1D illustrates various views of a retainer 100 in accordance with some

embodiments. FIGS. 1A-1D illustrate a bottom view, isometric view, side view, and front view respectively of a retainer 100 made using additive printing, such as 3D printing. The retainer 100 is designed to cover buccal surfaces, lingual surfaces, occlusal surfaces, and incisal surfaces of the teeth.

The illustrated retainer 100 is designed with a complementary shape to the patient dental anatomy such that substantially all of the top or bottom teeth are covered by the retainer 100 when worn by the patient. The retainer can be directly made using 3D printing. Various materials can be used with the 3D printing process to make the retainer 100. Examples of suitable materials include nylon 12 and other transparent materials.

[0159] The retainer 100 offers a number of advantages over prior art retainers, in particular retainers made by thermoforming. For example, although the retainers described herein may generally be made by any appropriate fabrication technique, in some variations they may be made by 3D printing, allowing additional customization. For example, the use of an additive manufacturing method to make the apparatuses described herein may allow for patient-specific retainers. In contrast to thermoforming, the use of additive manufacturing does not use a mold of the teeth. With a retainer made with additive manufacturing no molding needs to be done at the dentist’s office. Instead the retainer can be made via additive manufacturing based on a scan of the patient’s teeth and anatomy. Additive manufacturing is also a more efficient process versus molding and trimming the retainer. Retainers made via additive manufacturing typically do not require trimming (e.g., laser trimming). Additive manufacturing creates less waste than thermoforming processes. The additional customization allows for more complicated and specific designs to incorporate in the retainer. For example, the doctor or patient could modify the thickness regionally based on the preferences or needs. The coverage of the teeth for the retainer could also provide substantially full coverage all over the teeth to retain teeth alignment post treatment. Patients that grind their teeth may benefit from a retainer with occlusal coverage to provide protection against teeth grinding.

[0160] FIGS. 2A-2D illustrates various views of a retainer 200 in accordance with some embodiments. FIGS. 2A-2D illustrate a bottom view, isometric view, side view, and front view respectively of a retainer 200 made using additive printing, such as 3D printing. The retainer 200 is designed to cover buccal surfaces and lingual surfaces of all the teeth, and the incisal surfaces of the anterior teeth. The retainer 200 has openings such that it does not cover the occlusal portions of the posterior teeth. The retainer 200 allows for increased occlusal settling post treatment. The retainer 200 covers the substantially all of the anterior teeth such that the alignment can be maintained post treatment.

[0161] FIGS. 3A-3D illustrates various views of a retainer 300 in accordance with some embodiments. FIGS. 3A-3D illustrate a bottom view, isometric view, side view, and front view respectively of a retainer 300 made using additive printing, such as 3D printing. The retainer 300 is designed to cover lingual surfaces, a portion of the buccal surfaces, and incisal surfaces of the teeth. Material is removed from the occlusal surfaces and the buccal side of the anterior teeth. The full lingual coverage is similar to a fixed style anterior retainer configuration. The retainer 300 offers multiple advantages. The retainer 300 configuration allows for increase occlusal settling post treatment. The retainer 300 configuration removes the coverage from the teeth that are most visible and thus, improves the aesthetics of the retainer. The retainer 300 configuration provides full coverage on the lingual side of the anterior teeth to provide support to retain the anterior alignment of the teeth post treatment.

[0162] FIGS. 4A-4D illustrates various views of a retainer 400 in accordance with some embodiments. FIGS. 4A-4D illustrate a bottom view, isometric view, side view, and front view respectively of a retainer 400 made using additive printing, such as 3D printing. . The retainer 400 configuration allows for the full coverage on anterior teeth to retain alignment post treatment of the anterior teeth and only lingual surface coverage of the posterior teeth. The retainer 400 configuration allows for increased wall thickness on the lingual surface of the posterior teeth to retain the arch shape. The retainer 400 configuration allows the reduced coverage of buccal surface on the posteriors to increase patient comfort and promote better occlusal settling post treatment. The additive manufacturing process allows for a regional increase in the wall thickness on the lingual face of the posterior teeth to impart additional force and enough force to retain the arch position post treatment.

[0163] FIGS. 5A-5D illustrates various views of a retainer 500 in accordance with some embodiments. FIGS. 5A-5D illustrate a bottom view, isometric view, side view, and front view respectively of a retainer 500 made using additive printing, such as 3D printing, in accordance with some embodiments. The retainer 500 has a configuration similar to the retainer 400 but also includes struts that span across the palate between the opposing lingual surfaces of the retainer 500. The retainer 500 configuration with the struts increases the stiffness (e.g., lateral stiffness) on the posterior teeth if they start to move out of alignment. The retainer 500 offers similar advantages to the retainer 400 but with the ability to provide increased lateral forces on the posterior teeth.

[0164] FIGS. 6A-6D illustrates various views of a retainer 600 in accordance with some embodiments. FIGS. 6A-6D illustrate a bottom view, isometric view, side view, and front view respectively of a retainer 600 made using additive printing, such as 3D printing. The retainer 600 has a configuration similar to the retainer 500 but instead of struts includes full palatal coverage between the opposing lingual surfaces of the retainer. The retainer 600 configuration with the palatal coverage further increases the lateral forces on the posterior teeth. The retainer 600 offers similar advantages to the retainers 400, 500 but with the ability to provide increased lateral forces on the posterior teeth.

[0165] FIGS. 7A-7D illustrates various views of a retainer 700 in accordance with some embodiments. FIGS. 7A-7D illustrate a bottom view, isometric view, side view, and front view respectively of a retainer 700 made using additive printing, such as 3D printing. The retainer 700 is designed to cover the lingual surfaces, a portion of the incisal surfaces, occlusal surfaces, and posterior buccal surfaces of the teeth. The retainer 700 provides similar advantages to the retainer 100 discussed above. In contrast to the retainer 100 the retainer 700 removes some of the coverage of the buccal surfaces of the anterior teeth. The removal of the coverage of the buccal surfaces of the anterior teeth increase the overall aesthetic appeal of the retainer 700.

[0166] FIGS. 8A-8D illustrates various views of a retainer 800 in accordance with some embodiments. FIGS. 8A-8D illustrate a bottom view, isometric view, side view, and front view respectively of a retainer 800 made using additive printing, such as 3D printing. The retainer 800 covers the lingual surface, a portion of the buccal surface, and the lingual and buccal surfaces of both of the terminal molars. The retainer 800 includes a bar shaped to run along the buccal and lingual surfaces of the teeth between the two terminal molars. The retainer 800 has reduced overall tooth coverage that allows for increased occlusal settling and improved patient comfort. The material of the bars and other portions of the retainer can be tailored to provide the desired physical properties. For example, the thickness can be increased regionally to increase the force applied to the teeth if they start to move out of alignment.

The removal of the palate coverage may also reduce the retainer’ s 800 impact on speech.

[0167] FIGS. 9A-9D illustrates various views of a retainer 900 in accordance with some

embodiments. FIGS. 9A-9D illustrate a bottom view, isometric view, side view, and front view respectively of a retainer 900 made using additive printing, such as 3D printing. The retainer 900 covers the lingual surface and a portion of the buccal surface of all the teeth except the terminal molars. The terminal molars are completely covered by the retainer 900. The retainer 900 does not include occlusal coverage of the teeth, with the exception of the two terminal molars. The retainer 900 includes a bar shaped to run along the buccal surfaces of the teeth between the two terminal molars. The retainer 900 also includes full palatal coverage. The retainer 900 provides increased lateral stiffness with the palatal coverage that can be useful for retaining an expanded arch post treatment. The retainer 900 provides less coverage on the buccal surfaces that can be more aesthetically pleasing. The occlusal openings of the retainer allow for occlusal settling post treatment.

[0168] FIGS. 10A-10D illustrates various views of a retainer 1000 in accordance with some embodiments. FIGS. 10A-10D illustrate a bottom view, isometric view, side view, and front view respectively of a retainer 1000 made using additive printing, such as 3D printing. The retainer 1000 covers the lingual surfaces, occlusal surfaces, and buccal surfaces of the teeth with the exception of the buccal surfaces of the anterior teeth. The retainer 1000 also includes full palatal coverage. The retainer 1000 provides increased lateral stiffness with the palatal coverage that can be useful for retaining an expanded arch post treatment. The retainer 1000 provides substantially full coverage on the posterior teeth to retain alignment post treatment. The retainer 1000 provides an opening on the buccal surfaces of the anterior teeth to increase aesthetics of the retainer 1000. The retainer provides substantially full lingual coverage on the anterior teeth to provide additional support to the anterior teeth to maintain their position post treatment.

[0169] FIGS. 11 A-l 1D illustrates various views of a retainer 1100 in accordance with some embodiments. FIGS. 11 A-l 1D illustrate a bottom view, isometric view, side view, and front view respectively of a retainer 1100 made using additive printing, such as 3D printing. The retainer 1100 covers the lingual surfaces, occlusal surfaces, and buccal surfaces of the teeth. The retainer 1100 also includes palatal coverage. The palatal coverage is shaped such that it can function as a rapid plate expander. The retainer 1100 provides increased lateral forces with the palatal coverage that can also be useful for retaining an expanded arch post treatment. The palatal coverage portion of the retainer extends from the lingual surfaces of the posterior teeth but not the lingual portion of the anterior teeth. The retainer 1100 provides substantially full coverage on the posterior teeth to retain alignment post treatment. The configuration of the retainer 1100 allows the doctors to have the option to use a rapid palate expander post treatment of arch expansion in order to maintain expansion as well as retain the position of the teeth post treatment.

[0170] FIGS. 12A-12D illustrates various views of a retainer 1200 in accordance with some embodiments. FIGS. 12A-12D illustrate a bottom view, isometric view, side view, and front view respectively of a retainer 1200 made using additive printing, such as 3D printing. The retainer 1200 is designed to cover buccal surfaces, lingual surfaces, occlusal surfaces, and incisal surfaces of the teeth.

The illustrated retainer 1200 is designed with a complementary shape to the patient dental anatomy such that substantially all of the top or bottom teeth are covered by the retainer 1200 when worn by the patient. The retainer 1200 offers many of the benefits of the retainer 100 discussed above. The retainer 1200 also includes a mandibular advancement feature 1202. The retainer 1200 provides the doctor with the option to retain Class II correction while also retaining alignment of the other teeth post treatment.

[0171] FIGS. 13A-13D illustrates various views of a retainer 1300 in accordance with some embodiments. FIGS. 13A-13D illustrate a bottom view, isometric view, side view, and front view respectively of a retainer 1300 made using additive printing, such as 3D printing. The retainer 1300 is designed to cover buccal surfaces, lingual surfaces, occlusal surfaces, and incisal surfaces of the teeth.

The illustrated retainer 1300 is designed with a complementary shape to the patient dental anatomy such that substantially all of the top or bottom teeth are covered by the retainer 1300 when worn by the patient. The retainer 1300 also includes a mandibular advancement feature 1302 and a rapid palatal expander. The retainer 1300 provides the doctor with the option to provide a patient with a rapid palatal expander and a mandibular advancement feature. The retainer 1300 can provide an expanded arch, Class II correction, and also retaining alignment of the other teeth post treatment.

[0172] FIGS. 14A-14D illustrates various views of a retainer 1400 in accordance with some embodiments. FIGS. 14A-14D illustrate a bottom view, isometric view, side view, and front view respectively of a retainer 1400 made using additive printing, such as 3D printing. The retainer 1400 is designed to cover buccal surfaces, lingual surfaces, occlusal surfaces, and incisal surfaces of the teeth.

The illustrated retainer 1400 is designed with a complementary shape to the patient dental anatomy such that substantially all of the top or bottom teeth are covered by the retainer 1400 when worn by the patient. The retainer 1400 offers many of the benefits of the retainer 100 discussed above. The retainer 1400 also includes a solid occlusal mandibular advancement feature 1402 on the upper posterior teeth. The solid occlusal mandibular advancement feature on the upper posterior teeth can be used to provide treatment of Class II correction. The retainer 1400 can be used as a companion device for retaining teeth positioning post Class II correction. The ability to manufacture the occlusal mandibular advancement feature (which may be solid and/or monolithic) with additive manufacturing can increase the durability of the solid occlusal mandibular advancement feature.

[0173] FIGS. 15A-15D illustrates various views of a retainer 1500 in accordance with some embodiments. FIGS. 15A-15D illustrate a bottom view, isometric view, side view, and front view respectively of a retainer 1500 made using additive printing, such as 3D printing. The retainer 1500 is designed to cover buccal surfaces, lingual surfaces, occlusal surfaces, and incisal surfaces of the teeth.

The illustrated retainer 1500 is designed with a complementary shape to the patient dental anatomy such that substantially all of the top or bottom teeth are covered by the retainer 1500 when worn by the patient. The retainer 1500 offers many of the benefits of the retainers 100 and 1400 discussed above. The retainer 1500 also includes a monolithic occlusal mandibular advancement feature 1502 on the upper posterior teeth. The solid occlusal mandibular advancement feature 1502 on the upper posterior teeth can be used to provide treatment of Class II correction. The retainer 1500 can be used as a companion device for retaining teeth positioning post Class II correction. The ability to manufacture the solid occlusal mandibular advancement feature with additive manufacturing can increase the durability of the solid occlusal mandibular advancement feature.

[0174] The additive manufacturing processes described herein allow for additional customization of the color and other aesthetic aspects of the retainer. For example, the colors of the retainer can be selected to match natural tooth colors or decorative colors can be used for improved aesthetics.

[0175] FIG. 16 illustrates a retainer 1600 in accordance with some embodiments. The retainer 1600 includes an increased cut-line on the lingual side of the retainer/aligner, forming a gingival covering region on this side, which may increase the stiffness of the apparatus and therefore the force placed on the teeth. The retainer 1600 can be used with additive manufacturing and can include multiple different materials.

[0176] Both hard and soft materials can be used with the additive manufacturing process to improve the comfort of the retainer 1600 while still providing adequate mechanical support to the teeth. The use of multiple materials and additive manufacturing can also allow for the improved integration of the retainer with sleep appliances. For example, the retainer made via additive manufacturing can be designed to engage with or work with specific sleep appliance designs. Additive manufacturing also allows for the integration of additional items, such as sensors with the retainer configuration. In one example, one or more glucose sensors could be integrated into the retainer to measure glucose levels for patients with diabetes.

[0177] FIGS. 17A-17B illustrate additional embodiments of retainers. FIG. 17A shows a retainer 1700 made from additive manufacturing that includes a universal attachment (shown here as a dovetail adapter) on one or more locations. The universal attachment (e.g., dovetail adapter) can be used to integrate features such as the mandibular advancement feature, sleep devices, bite guards, etc. The size and configuration of the universal dovetail adapter can be designed to have a complementary structure with the

[0178] FIG. 17B illustrates another embodiment of a retainer 1750. The illustrated retainer 1750 includes a thicker posterior base, along with an embedded stiffening element (e.g., wire). The wire can be made out of a shape memory material such as a nickel titanium ahoy. The wire can provide additional structural support to control the force exerted on the teeth. [0179] FIGS. 18A-18B illustrate additional embodiments of retainers. FIG. 18A illustrates a retainer 1800 with ridges configured to stop diastema post treatment. FIG. 18B illustrates a retainer 1850 with a variable thickness.

[0180] FIGS. 19A-19B illustrate additional embodiments of retainers. FIG. 19A illustrates a portion of a retainer 1900 that is also used as a night guard to prevent damage from grinding teeth together. The retainer 1900 illustrated in FIG. 19A shows a thicker flat occlusal surface to provide protection from grinding.

[0181] FIG. 19B shows a retainer 1950 with an interproximal support feature 1960 that may modify the stiffness of the retainer, including protecting against arch relapse. In particular, regions of the device (e.g., in the pockets) corresponding to the interproximal regions of the teeth 1960 may be configured to be more compliant than the main body of the device. For example an interproximal support feature can include one or more voids, openings, or open spaces to decrease the stiffness of the interproximal region relative to solid interproximal support features. In some cases the interproximal region 1960 can be made out of a less rigid material than the retainer material used in the unitary body. The use of a less stiff material for the interproximal support region 1960 may allow the retainer to extend further into the interproximal spaces between the teeth. The interproximal support feature(s) 1950 can provide better control of the tooth position and provide additional protection against relapse. The use of a stiffer material for the interproximal support feature may otherwise make it more difficult, or uncomfortable, to place and remove the retainer from the patient’s mouth. The use of a more compliant/less stiff interproximal support region may allow some of the retainer material farther into the interproximal spaces than would otherwise be possible, protecting against relapse. Thus, although the overall stiffness of the retainer may be greater with interproximal supports, this effect is achieved by making the material forming the interproximal support less stiff than the retainer in this region (e.g., if it were to have a solid structure in the interproximal region, for example) would otherwise be. In FIG. 19B, the reduced stiffness in the interproximal region may be achieved by the geometry of the material, by using a locally more compliant material, or both.

[0182] FIG. 20 illustrates additional embodiments of retainers. FIG. 20 shows a retainer 2000 for use during the day and a retainer 2050 for use at night version. The day retainer 2000 and night retainer 2050 can each be made via additive manufacturing from the scan of the patient anatomy. The day retainer 2000 has a smaller profile to provide support while also improving the aesthetic of the retainer. The night retainer 2050 provides full coverage and support and is designed to be worn at night.

[0183] The retainers described herein can also be designed for use by patients who have mixed dentition where a full coverage is not recommended as some teeth might be in the process of eruption.

The retainers can be used for patients where posterior open bites are present to allow for settling of the occlusion. The retainers can be also be used in cases where there was a deep bite that was improved by the treatment. Some retainers may not have occlusal coverage or reduced occlusal coverage for cases where a posterior force is undesirable. For example, a lack of posterior force may be desirable to avoid making teeth to intrude as that is not recommended for use with patients that have deep bite conditions. A current commercial version of a retainer that can be improved through the use of additive manufacturing is the Hawley retainer that is made from a stainless-steel wire and some acrylic that covers the palatal.

The retainer illustrated in FIGS. 21A-21B can be used to treat many of these conditions and can be made by additive manufacturing without the use of a wire that is not aesthetically pleasing.

[0184] FIGS. 21 A-21B illustrate a retainer in accordance with some embodiments. FIG. 21 A shows two different lateral views of the retainer 2100. The retainer 2100 includes a clear bar and hooks. FIG.

21B illustrates a top view of the retainer 2100. FIG. 21B shows a clear buccal bar and a clear lingual bar. The retainer 2100 can also include a retention bar across the palatal portion of the retainer to increase the strength of the retainer. The retainer 2100 can provide similar benefits to the patient as a conventional Hawley retainer but without the use of wires and other less aesthetically pleasing components. The use of additive manufacturing allows for the retainer to be made specifically for the patient out of a plastic material without the use of wires or metal. The retainer shown in 2100 FIGS. 21A-21B has no posterior occlusal coverage to allow occlusion to settle once the treatment is finished. The retainer 2100 shown in FIGS. 21A-21B can help for cases with POB where wearing a full coverage retainer cause the dental conditions to worsen. Additional advantages of the retainer 2100 shown in FIGS. 21A-21B include a clear and aesthetically pleasing design that is convenient and allows for settling of the occlusion. In contrast to the retainer 2100 shown in FIGS. 21A-21B, the commercially available ClearBow retainer only has a clear bar on the anterior teeth and does not include a bar over the posterior teeth.

[0185] FIG. 22 illustrates a method 2200 for planning a patient-specific retainer device. The method can include: receiving a three-dimensional representation of a patient dental anatomy, displaying at least a portion of the three-dimensional representation of the patient dental anatomy; providing one or more options associated with retainer configurations, the one or more options including a palatal configuration, an anterior teeth coverage configuration, and a posterior teeth coverage configuration; providing one or more add-on options for the retainer; receiving responses or instructions to the one or more options and one or more add-on options; and preparing a model of a custom retainer based on the patient dental anatomy and the responses or instructions to the one or more options and one or more add-on options.

The methods can further include displaying an image of the custom retainer overlying the three- dimensional representation of the patient dental anatomy. Examples of the anterior teeth coverage configuration and the posterior teeth coverage configuration include options for buccal coverage, lingual coverage, and occlusal coverage for the anterior teeth and the posterior teeth. Examples of the add-on options for the retainer include one or more of: a protrusion, tab, hook, or other attachment structure configured to attach a rubber band, a slot configured to attach a rubber band, a mandibular advancement feature, a ramp, a gingival support region, a thickened base region, and a plurality of ridges. Examples of the custom retainers include any of the retainers described herein.

[0186] Any of the apparatuses (e.g., retainers) described herein may be configured to include one or more gaps or spaces for erupting teeth and/or may be configured to constrain the movement of the adjacent teeth to prevent them from moving into the space where the erupting tooth should fit. For example, a retainer may include a space or gap near the gum line (when worn) but the region above the gum line may include a spacer to prevent movement of the adjacent teeth into this region.

[0187] As mentioned above, any of the retainer described herein may have regions of greater or lesser thickness. The thicknesses of regions around teeth that are more prone to relapse from orthodontic movement bay be greater than the thicknesses of other regions. For example if a particular tooth or teeth has been moved more than other teeth, the lingual, buccal, and in some variations occlusal regions of the retainer around this tooth or teeth may be thicker compared to regions around other teeth (e.g., based on how far the teeth has been moved during treatment). Alternatively or additionally, the dental professional (e.g., dentist, orthodontist, etc.) may select one or more teeth to provide additional support. An apparatus may highlight candidate teeth (e.g., based on the total movement during treatment) to the user (e.g., dental professional) for selection to have additional support/retention, e.g., by increasing the thickness in the regions around the tooth.

[0188] Thus, in general, the user interface for a user designing a retainer may include controls allowing the user to select teeth for additional support or retention, and/or for selecting the thickness of various regions and/or for selecting the material from which the appliance will be constructed. In some variations, the user interface may allow the user (dental professional) to select which regions to include in the retainer (e.g., anterior tooth engaging region, posterior tooth engaging region (s), palatal region, etc.).

[0189] Any of the methods described herein may include digital processes for designing and fabricating a removable retainer (e.g., a removable Phase I orthodontic retainer) such as those described herein. These processes may reduce or eliminate the need for taking an alginate impression of the maxillary arch and pouring a mold such as a quick-set plaster model. They may also eliminate or reduce the need for manual steps to thermoform, mark, trim and polish the device. As mentioned, described herein are additive manufacturing techniques that use materials with a higher modulus for rigidity and/or multi materials with a mix of high modulus and soft durometer for comfort. Retainer designs can have variable cross-sectional thickness as well as decorative and identifying features in the design of the retainer.

[0190] For example, FIG. 23 illustrates a schematic of one method of designing and manufacturing a retainer as described herein. In FIG. 23, the treatment is completed 2301 and a scan of the patient’s teeth is taken 2303 (e.g., by iTero™ scanner). This scan is sent, with instructions to the lab 2305, where processing occurs to design the retainer(s) and a digital representation of the retainer(s) is/are sent to the dental professional to approve 2307. Alternatively, the dental professional may aid in the design of the retainer(s) directly, e.g., through a user interface showing a digital representation of the patient’s teeth and/or allowing the user to select features of the retainer(s). Until the design is approved, the instructions (from the physician) may be used to iterate the design process. Once the design is approved by the physician 2309 (and in some variations, the apparatus may automatically monitor and approve/flag the design), the design manufactured, e.g., by the lab, and shipped to the dental professional’s office and/or directly to the patient 2311. [0191] In general, as mentioned above, any of the retainers described herein may be helpful to maintain palatal expansion (after a palatal expansion procedure). Such procedures are often performed on children, for whom there are few permanent teeth.

[0192] In general, also described herein are digital process for designing and fabricating a removable orthodontic retainer. These processes may reduce or eliminate the need for taking impressions (e.g., an alginate impressions) of the maxillary arch and pouring a model (e.g., quick-set model). They may also eliminate the manual steps required to thermoform, mark, trim and polish the device. As mentioned, these method may include fabrication by additive manufacturing technology (e.g., 3D printing) using materials with a higher modulus for rigidity and/or multi materials with a mix of high modulus and soft durometer for comfort. Retainer designs can have variable cross sectional thickness as well as decorative and part identifying features in the design. For example, described herein are retainers made with the methods discussed above.

[0193] For example, FIG. 24 illustrates one example of a customized retainer as described herein. In this example, a posterior portion of the palatal section has been removed (cut out) to allow additional room for the tongue, enhancing comfort, and reducing material cost and time to manufacture. In any of these variations, the palatal area may be customizable; it can contact the tissue or have clearance. In FIG. 24A, the tooth-containing regions (e.g., the anterior tooth-containing region and at least a portion of the posterior tooth-containing region) is cut-away, exposing the primary teeth and allowing exfoliation and eruption (there is clearance around exfoliating and eruption crowns in this example; the cut away region is customizable). The permanent crowns may be held by the appliance, to maintain the spacing. Occlusal coverage of permanent crowns may also help prevent passive eruption. Additionally, if the permanent anterior teeth or permanent molar need additional room to erupt, space can be designed for them to erupt into (eruption compensation) within the retainer. This may allow the retainer to maintain palatal expansion and permanent teeth (anterior and molars).

[0194] FIG. 24B illustrates another example of a retainer including a full palatal section that may provide maximum stiffness (this region may also be customized, as described above; e.g., it may include one or more cut-out regions, and/or may contact the palate or have an offset from palate surface). The tooth-containing regions may include cut-away regions for primary teeth exfoliation and eruption (in this example, there is clearance around exfoliating and eruption crowns in this example but the cut away region is customizable). The apparatus may also allow capture the permanent crowns for maintenance of spacing of teeth following the orthodontic procedure. Additionally, if the permanent anterior teeth or permanent molar need additional room to erupt, space can be designed for them to erupt into (eruption compensation). Occlusal coverage of permanent crowns may prevent passive eruption. These retainers may provide the ability to maintain palatal expansion and anterior tooth alignment. The example shown in FIG. 24C is similar to that shown in FIG. 24B, but has a contour of the lingual side of the primary teeth. This variation is also includes a cut out region for exfoliation and eruption (the lateral sides).

[0195] FIG. 25 shows another example of an apparatus similar to that shown in FIG. 24B, including a full palatal section, however it include a central opening 2503 through the palatal region. This variation may be safer for use, particularly by a child, if the device were to be swallowed. Again the apparatus is customizable. For example, one or more holes or openings may be included, a contact palate may be included, and/or an offset from palate surface may be included. As above, cut-away regions in the tooth- containing portions may allow space for primary teeth exfoliation and eruption (e.g., there is no clearance around exfoliating and eruption crowns in this example but the cut away region is customizable). In some variations, for esthetics on the anterior, the device may cover only the lingual surface of the anterior teeth, to help retain the teeth (e.g., for space maintenance) and to allow passive eruption. In this example the posterior tooth-containing region may capture the permanent molar crowns to help maintain the tooth spacing; in addition, occlusal coverage of permanent molars may prevent passive eruption of the teeth. Thus, this variation may also maintain palatal expansion and anterior tooth alignment.

[0196] FIG. 26 shows another example of a retainer as described herein. In this example, the retainer does not include an anterior tooth-retaining portion (anterior teeth region). In addition, this retainer shape may also be further customized to remove coverage over any teeth that may need additional space in which they can erupt into (e.g., eruption compensation). The area around the crowns can have permanent teeth eruption compensation room, allowing space for erupting teeth to fully erupt.

[0197] FIG. 27 is another example of a retainer as described herein. In this example, the apparatus includes an anterior tooth-retaining region, and includes clearance around exfoliating and eruption crowns (shown as cut away regions 2701, 2701’)· The permanent crowns are captured within the posterior tooth- retaining region 2703, 2703’, for maintenance of the tooth spacing. In FIG. 28, permanent crowns include occlusal coverage (occlusal surfaces) to prevent passive eruption. Additionally, if the permanent anterior teeth or permanent molars need additional room to erupt, space can be designed for them to erupt into (eruption compensation). These apparatuses may maintain palatal expansion and anterior tooth alignment.

[0198] In general, the custom, patient-specific phase I retainers described herein may be made by digital processing, additive manufacturing and may be designed to: maintain permanent tooth position, allow for primary teeth eruption, provide space maintenance, prevent passive eruption, and/or maintain palatal expansion.

[0199] These retainers may include any combination of: full palatal width for rigidity (e.g., one size fits all or with control of: contacting the palate or offset from palate and/or thickness of the trans palatal arch), one or more holes in the palate (of any other shape for choking safety); one or more cut away regions in the palate to maximize room for tongue (e.g., enhancing comfort, including one size fits all or control of where the trans palatal arch covers), cut-away regions for primary tooth exfoliation (one size fits all or with control of where to cut away from teeth), encapsulate the permanent teeth to maintain tooth alignment, space maintenance, eruption compensation, and/or prevent passive eruption (one size fits all or control of tooth coverage), no buccal coverage of anterior teeth for esthetic (e.g., one design or control of how much anterior tooth will be covered), pre-made selections of different occlusal thickness or control of occlusal thickness, pre-made occlusal shape or control of occlusal shape (with cusps or flat), and/or including identifier (e.g., ID number) or data matrix in the design [0200] These retainers may require less manual processing to make the retainer (e.g. eliminating or reducing the need for alginate impressions, plaster model, thermoforming, marking, trimming and polishing). Digitizing the retainer process will enable a menu of choices for retainers (palatal offset, clearance around exfoliating primary or erupting permanent dentition, occlusal thickness ... etc.). The digital workflow may also enable tooth movement (treatment) in some oral regions while retaining in other areas. The use of additive manufacturing with superior material properties may enable more comfort to the patient (e.g. thinner cross sections with the same rigidity, accurate parts (no warping) and multi- material/different durometer capability. Unlike thermoforming, these methods may allow variable cross sectional thickness. Any of these apparatuses may also include decorative features and useful part identification numbers or data matrix information that can be included into the retainer design with additive manufacturing.

FABRICATION OF RETAINERS

[0201] As mentioned, any of the methods and apparatuses described herein may include apparatuses, including software and firmware, for running on a processor to perform any of the methods, including in particular, software for creating the retainers, including interactively creating the retainers with a dental professional, and fabricating the retainers. For example, described herein are methods and apparatuses (including in particular a set of non-volatile instructions that control a processor to create a retainer by 3D printing (direct fabrication), including creating the retainer shape automatically. The retainer type can be a Phase I retainer (e.g., for use after phase I treatment like rapid arch expansion), or after other orthodontic treatment.

[0202] The steps to building a retainer shape may include: building a scan basis (e.g., scan of the patient’s teeth, gingiva and, for upper teeth, palatal region); create split curves (e.g., segment the scan); create scan axis curve; build a bottom grid of the retainer by scan palate and crown; build a top grid of retainer, from bottom grid; build a retainer shape from bottom grid and top grid; and export the result (e.g., as a digital file, such as an STL file) for fabrication.

[0203] In general, these methods and apparatuses may automatically create retainer shape from a digital file and/or an initial scan of the patient’s teeth (e.g., a direct scan or an impression scan), and may save result as a digital file for 3D printing. The retainer shape may be customized for each patient. The user interface may allow customization. The retainer may cover full or partially palate surface, all/some tooth crowns, buccal gingiva side. The thickness of palate, crown and buccal can be set differently, and smoothly changed, in automatic way. The clearance of retainer to palate, tooth crown and gingiva can be set differently. A tag string and/or bar code may be included on the retainer for manufacture, shipping, and user tracking. These retainers may also include and allow space for partially erupted teeth, which may be selected by the user as well.

[0204] For example, a user interface may provide a variety of templates that may be modified for the retainer. The tools in the user interface may provide the user with options for including various regions, including tooth-enclosing regions (e.g., anterior tooth-containing region, posterior tooth-containing regions), palatal regions, etc. In addition, all or parts of these various regions may be interactively selected for removal. For example, the user interface may allow the removal of all or a portion of the lingual side of the tooth-enclosing regions, all or a portion of the buccal side of one or more of the tooth enclosing regions, all or a portion of the occlusal side of one or more of the tooth-enclosing regions, and all or a portion of the palatal region. In addition, the tools may allow the user to select the thickness of these different regions and portions (e.g., the palatal region, the buccal/lingual/occlusal regions of the various tooth-enclosing regions, etc.) and may also be used to select or control the smoothness of these various regions, including in particular the smoothness of the lingual-facing surface of the palatal region.

[0205] The methods and apparatuses (including software) described herein may be used to modify region of any of the retainers described herein. For example, the user interface may be configured to allow a user to select controls to adjust the thickness and clearance for crown, buccal and lingual sides of the retainer. For example, the patient’s dental arch(s) may be displayed in the user interface and controls may allow selection of various regions forming the dental retainer; the user may drag and drop, for example, these various portions onto the dental arch, or may select them from a pull-down menu, etc. A digital model of the retainer may be manipulated (rotated, enlarged, etc.) by the user, and regions may be modified for thickness, extent, etc. by selecting one or more controls (e.g., buttons, etc.). The user interface may be a visual or display user interface.

[0206] For example, a user interface may allow the user to create a retainer shape for 3D printing. The formation of the retainer may including preparing a digital model that can be manipulated. If a digital model of the patient’ s teeth, gingiva and palate (for upper arch) is not already included, the methods and apparatus may generate them from scan(s) of the patient’s oral cavity and/or impressions of the patient’s teeth. For example, one or more scans may be segmented to isolate the teeth (e.g., including tooth crowns) as separate objects, the gingiva can also be extracted from the initial scan(s), and morphed from the initial to a final (post-treatment) configuration following the tooth and/or palatal movement. The palate may be similarly modeled. Thus, the final model may include tooth crown, at least partial gingiva surfaces, and (for the upper arch) the palate. This model may be used to generate the retainer model(s).

[0207] The methods and apparatuses may include setting up and modify boundaries for the retainer. Boundaries may be set manually (e.g., by drawing lines on the 3D surface of tooth, gingiva and palate model build the boundary), fully automatically (e.g., from gingiva line and automatic detected curves, including posterior and cutout points), or semi-automatically (adjustable automatic, e.g., boundary is initially build by full automatic way, then adjusted manually around the surface manually). For example, this may include changing and adjusting the retainer coverage of the teeth, gingiva and palate in a variety of different ways. The user may create dental retainers that fit many different application and patient. As mentioned, in general, holes may also be added to create retainer. The hole(s) can be around the teeth, or in the palate surface.

[0208] For example, FIG. 28 illustrates one example of a prototype user interface that may be used, including a variety of user-selectable controls. In FIG. 28, the user interface includes pull-down menus and tabs 2801 with options for adding/importing a patient’s teeth and/or treatment plan, and for modifying portions of the digital model, including the final position of the upper and/or lower arch. The user interface may include a display region in which the patient’s arch and/or a manipulatable retainer may be displayed.

[0209] FIGS. 29A-D shows an example of a retainer as it may be displayed in a user interface such as the one shown in FIG. 28. In FIG. 29 A, the retainer 2903 includes an anterior tooth-containing region 2905 (circled region), two posterior (permanent molar) tooth-retaining regions 2907, 2907’, a flat posterior boundary 2911 and smooth cutout curve regions 2915, 2915’ between the anterior and posterior tooth-containing regions. The retainer also includes a 3D scan/QR code tab 2917 extending as a tab from the back of the retainer (this may be removable). As shown in FIG. 29B, rotated slightly from the view of FIG. 29 A, the bottom, lingual-facing surface 2921 may be smooth/smoothed. FIG. 29C shows a bottom view (rotated from the view showing the upper dental arch with the retainer in FIG. 29A and 29B). The upper surface (which may be configured to be offset 2931 relative to the patient’s palate, may include an identifying tag 2923 (shown as an alphanumeric identifier) inset (e.g., etched into the palatal region). FIG. 29D shows another rotation, showing the back (posterior) of the retainer on a model of the patient’s teeth, showing the thicknesses 2935 of the palatal and crown regions.

[0210] FIG. 30A illustrates a high-level process flow diagram for a method of designing and fabricating a retainer as described herein. In FIG. 30A, the method may begin by generating a digital model of the patient’s teeth (e.g., upper jaw) 3301. The digital model may be formed by scanning the jaw directly, e.g., using an intraoral scanner, and/or scanning a model of the patient’s teeth, or any other appropriate method. This information may be collected directly in the user’s (e.g., dental practitioner’s) office, and it may be transmitted to the fabricator (e.g. a remote lab, or a local, e.g., benchtop fabricator 3303. The digital model may be processed to select the retainer features and used to design the retainer, as described in greater detail herein 3305. The design may be interactively made and/or approved by the user 3311 (shown here as just a final approval stage, but other steps, including feature selection from a menu of options, etc. may be included in this iterative design loop, as an optional step). Once finally approved by the user, the retainer may be fabricate 3307 and shipped to the patient and/or the user for delivery to the patient 3309.

[0211] FIG. 30B illustrates a method of forming a retainer as described herein. This method may be used as part of the overall process of FIG. 30A. For example, the method or apparatus (e.g., software) may begin by importing a file including the treatment plan (e.g., showing tooth movements, etc.) and the initial and final position of the patient’s teeth 3001. The method may then rescan and map the tooth surface from the model to a 2D height map 3003, and define the boundary of the retainer 3005. A mesh model may then be built by triangulating the 2D points with the boundary 3007. The user may at any point indicate which features of the retainer to include (e.g., anterior tooth-containing regions, posterior tooth-containing regions, palatal region, etc.), and may indicate openings/holes, and removed portions, thicknesses, etc.). The software may calculate the retainer to these specifications and may confirm that the retainer will effectively retain the teeth and/or palate in the desired configuration. For example, the software may define and adjust the clearance of the palatal-facing side of the retainer when it includes a palatal region 3009, and may also adjust the thickness and/or smooth the opposite (lingual-facing) surface 3011. The shape of the retainer may then be built 3013, and any markings may be added 3015. If the retainer is to be printed directly from the digital model, it may be converted into a printable format (e.g., by building a matrix mesh 2017) and exported for printing 3019.

[0212] FIG. 30C is a diagram showing an example of an retainer fabrication system 3100A. The modules of the retainer fabrication system 3100A may include one or more engines and datastores. A computer system can be implemented as an engine, as part of an engine or through multiple engines. As used herein, an engine includes one or more processors or a portion thereof. A portion of one or more processors can include some portion of hardware less than all of the hardware comprising any given one or more processors, such as a subset of registers, the portion of the processor dedicated to one or more threads of a multi-threaded processor, a time slice during which the processor is wholly or partially dedicated to carrying out part of the engine’s functionality, or the like. As such, a first engine and a second engine can have one or more dedicated processors or a first engine and a second engine can share one or more processors with one another or other engines. Depending upon implementation-specific or other considerations, an engine can be centralized or its functionality distributed. An engine can include hardware, firmware, or software embodied in a computer-readable medium for execution by the processor. The processor transforms data into new data using implemented data structures and methods, such as is described with reference to the figures herein.

[0213] The engines described herein, or the engines through which the systems and devices described herein can be implemented, can be cloud-based engines. As used herein, a cloud-based engine is an engine that can run applications and/or functionalities using a cloud-based computing system. All or portions of the applications and/or functionalities can be distributed across multiple computing devices, and need not be restricted to only one computing device. In some embodiments, the cloud-based engines can execute functionalities and/or modules that end users access through a web browser or container application without having the functionalities and/or modules installed locally on the end-users’ computing devices.

[0214] As used herein, datastores are intended to include repositories having any applicable organization of data, including tables, comma-separated values (CSV) files, traditional databases (e.g., SQL), or other applicable known or convenient organizational formats. Datastores can be implemented, for example, as software embodied in a physical computer-readable medium on a specific -purpose machine, in firmware, in hardware, in a combination thereof, or in an applicable known or convenient device or system. Datastore-associated components, such as database interfaces, can be considered "part of" a datastore, part of some other system component, or a combination thereof, though the physical location and other characteristics of datastore-associated components is not critical for an understanding of the techniques described herein.

[0215] Datastores can include data structures. As used herein, a data structure is associated with a particular way of storing and organizing data in a computer so that it can be used efficiently within a given context. Data structures are generally based on the ability of a computer to fetch and store data at any place in its memory, specified by an address, a bit string that can be itself stored in memory and manipulated by the program. Thus, some data structures are based on computing the addresses of data items with arithmetic operations; while other data structures are based on storing addresses of data items within the structure itself. Many data structures use both principles, sometimes combined in non-trivial ways. The implementation of a data structure usually entails writing a set of procedures that create and manipulate instances of that structure. The datastores, described herein, can be cloud-based datastores. A cloud-based datastore is a datastore that is compatible with cloud-based computing systems and engines.

[0216] The retainer fabrication system 3100A may include a computer-readable medium and/or an input for receiving, for example, a 3D model of the patient’ s dentition, and in particular of the final (or anticipated final) configuration of the patient’s teeth. The computer-readable medium 102 may include any computer-readable medium, including without limitation a bus, a wired network, a wireless network, or some combination thereof. In some variations the system may include an input for receiving a treatment plan (treatment file) including a scan, such as a 3D scan, of the patient’s dentition; this input may be stored for access by the system later and/or immediately. For example, the 3D scan and treatment plan (or the final stage of the treatment plan) may be stored in a 3D dentition data store (not shown).

[0217] In FIG. 30B, the system 3100 may also include a 2D Height Map Fabrication Engine 3102, for translating the 3D model of the patient’s teeth in a final target arrangement into a 2D height map, a Retainer Boundary Engine 3104, for defining one or more boundaries of the retainer. The system may also include a Boundary Datastore 3114 that may specify one or more boundaries or boundary parameters to be applied. The system 3100 may also include a Mesh Building Engine 3106 that may build a mesh, e.g., by triangulation of the 2D height map with the boundary or boundaries of the retainer, a Clearance Engine 3108 that may adjust the clearance of the model retainer relative to the patient’s dentition (e.g., the clearance of the bottom surface of the model retainer relative to the teeth and/or palate), and a Smoothening and Thickness Adjusting Engine 3110 that may smooth the top surface and/or edges of the retainer model. In some variations the system may also include a Marking Engine 3112 that may add a patient-specific marking (e.g., an alphanumeric code, a QR code, etc.) to the retainer, by engraving and/or embossing; an Identification Marking Datastore 3116 may reference the marking to be included. Any of these systems may also include an Export Engine 3118 that may format the retainer model into a form for output by the system and/or for direct fabrication, e.g., by a 3D printer (e.g., as a stereolithography, or STL, file format). The various engines of the system may implement one or more automated agents configured to automatically perform any of the functions of the engine.

[0218] In some variations, the retainer to be formed is a thin shell shape, as described above. Thus, in some variations, the bottom surface may be constructed from jaw and tooth digital model of the final configuration, with some clearance added. The top surface may be constructed from the bottom surface, with a variable thickness. The bottom surface may be built, for example, by cutting from the original jaw scan. Alternatively, the bottom surface may be rebuild as a surface from a point cloud of crown and jaw. When rescanning the jaw and teeth as a 2D height map, the scan surface may be un- wrapped to 2D and the teeth and jaw rescanned to the height map, resulting in a bottom (e.g., palatal-facing) surface. The original jaw and crown points can be projected into the“scan surface”, and map to 2D. The distance to the“scan surface” is converted into height. The 3D shape / surface may be re-scanned (rasterized) as 2D height map points. The bottom surface mesh may be built from the 2D points, and the boundary.

[0219] The model of the patient’s teeth may be segmented (automatically, manually or semi- automatically) into regions, such as tooth/crown regions, gingiva, and palate, etc.) and further into buccal, lingual, occlusal surfaces. Automatic segmentation may be improved by using scan axis curves and occlusal curves. The user may define, or may correct automatically defined, regions such as the crown region, palatal region and buccal regions.

[0220] Thus, any of the methods and apparatuses (e.g., systems) for designing and/or fabricating a retainer as described herein may collect (e.g., may access, may gather, may receiving, may import, etc.) a digital model of the patient’s dentition (e.g., jaw(s)) either in a target final configuration to be retained, such as a 3D model of the patient’s dentition (teeth, and in some variations palate and/or gingiva) in the target arrangement, or a 3D model of the patient’s dentition with a key indicating the target arrangement. As mentioned above, this may include a treatment file and a scan (3D) of the patient’s dentition. All of these variations may be described as collecting the 3D model of the patient’ s target dentition. The 3D model of the patient’ s target dentition may be represented as a digital 3D model from which the retainer may be designed. As described above in reference to FIGS. 30B (and in the system of 30C), this may include rescanning and mapping the 3D model of patient’s target dentition as a 2D height map. One example of this rescanning and mapping the 3D model as a 2D height map is illustrated in FIGS. 33A- 46C.

[0221] For example, in FIGS. 33A-33B a 3D digital model of the patient’s dentition in the target arrangement is shown (FIG. 33A), and a thin shell retainer 3303 is shown fitting over the teeth (FIG.

33B). In this example the retainer includes a bottom surface 3305 that extends from jaw and tooth, with some clearance, and top surface 3307 that extends from bottom surface with a variable thickness.

Although this example includes a palate-spanning region, any of the retainers described herein may be formed using a similar method, including those without a full palatal region. The retainer may be digitally formed using a 3D model of the patient’ s dentition in the target configuration.

[0222] In general, the methods and apparatuses described herein for forming and/or fabricating a retainer may map the 3D model of the patient’s dentition in the target configuration into a 2D height map. FIGS. 34A-34D show an overview of on variation of this method. In FIG. 34A, the method or system may assume that there is scan surface with roughly the shape of jaw and teeth (e.g., crowns of the teeth); this surface can be un-warped into a flat surface in 2D image, as shown in FIG. 34B. The original jaw and crown points can be projected into the scan surface and mapped in 2D, as shown in FIG. 34C; the distance to the“scan surface” is converted into height. As shown in FIG. 34D, the 3D shape/surface may then be re-scanned (rasterized) as 2D height map points, and the bottom surface mesh of the retainer may then be built from the 2D points, and the boundary. The thickness (and therefore the top surface) of the retainer may then be determined and set. [0223] In any of these methods and apparatuses, the digital 3D scan (“jaw scan”) may be organized using a set of reference axes and/or split into various curves. FIG. 35A illustrates this scanning basis. As shown, a basis (coordinate) may be used to rescan jaw and crowns. For example, an XY plane is a plane that approximate crown centers of all teeth. An YZ plane may include the middle plate of left and right teeth. In this example, the origin is roughly the middle point center of canine crown centers. In FIG. 35, a lingual 3507 and buccal 3503 split curve are shown, and may be built from the gingival lines of each teeth. These curves may be used to define buccal, crown and lingual (palate) sections of jaw scan.

[0224] In addition, the original 3D scan (e.g., jaw scan or impression) may be split to palatal and buccal patches, as shown in FIGS. 36A-36C. In FIG. 36A, the palatal patch 3605 is shown, and is inside the lingual split curve (closer to the center), and the vertex normal is“upper” (n.z. > O.Of). As shown in FIG. 36B, the buccal patch 3607 is not inside palate patch, and roughly points in the buccal direction (e.g., outside and below the buccal split curve). The surface distance (e.g., Dijkstra distance) to the split curve may be less than some maximum (e.g., less than about 3 mm), which may remove extract material of the scan, as shown in FIG. 36C.

[0225] The scan axis curve is illustrated in FIG. 37A, and passes the crown centers of all teeth and contact points. The occlusal curve may be defined as the occlusal direction of all teeth. For any vertex in the jaw or tooth crown, it may be located as anterior (v.y. > 0 in the scan basis) or posterior (v.y. <0 in the scan basis). As shown in FIG. 37B, the scan plane may include an anterior point or region from an origin of scan basis, to the anterior vertex, and a posterior point or region, in the X direction and passing the posterior vertex. The intersection of the scan plane and the scan axis curve may be referred to as the scan axis point, and may be used for the scan for the occlusal point.

[0226] FIG. 38 further illustrates the basis and regions of the scan axis. As illustrated, for a vertex, the method or apparatus may find the scan plane, and the scan axis point, scan occlusal point, also the center axis point, and may build a scan axis basis by setting an origin as the scan axis point, Z is the direction from scan axis point to occlusal point, and the X axis as perpendicular to Z axis. The scan plane may be divided into 3 regions: a palate/lingual region (the boundary may be the link between scan axis and center axis point (e.g., x>0) and under the link line); a crown region, until the negative X axis (e.g., z>0), and a buccal side region (e.g., x<0, z<0).

[0227] As shown in FIG. 39, the scan curve may define a crown radius and a center radius. The scan curve may include 3 segments: a palate region (e.g., an arch with center in center axis point and center radius); a crown region (e.g., an arch with center in scan axis point and crown radius); and a buccal region (e.g., a line with distance to z axis equal to the crown radius). For one vertex, V, in palatal patch, crown or buccal path, the method or apparatus may project it into the scan curve as P; the distance of V to P may be referred to as the height.

[0228] As shown in FIG. 40 (similar to FIG. 34A), the surface may be scanned, e.g., using a scan curve. The anterior may be scanned starting from the origin of scan basis, and in the XY direction. The posterior may be scanned starting from the Y axis, and in the X direction. All of the scan curves may form the scan surface, which is an approximation of the shape of the jaw, including the palate, gingiva and tooth. Any 3D vertex of the jaw can be projected into the scan surface. A 2D height map may then be mapped from the 3D surface. As shown schematically in FIG. 41, for each scan curve, it can be un warped to a straight line, using the curve length to the start point. The scan surface can also be un-warped as a flat 2D surface. For vertex V in the 3D model, it is projected into the scan curve as P, then is“un warped” to the line. The distance from V to P is converted to the height to the line. For example, in FIG. 42A, the scan surface is shown in 3D; in FIG. 42B, the scan surface may be unwrapped to 2D and (FIG. 42C), the 2D height map of the jaw and crown may be determined.

[0229] From the 2D height map, the surfaces to build the retainer may be determined, setting the tooth and/or gingiva and/or palate surfaces. For example, as shown in FIG. 43, the jaw scan may include the original data from patient’s dentition, and may be virtually cut into palate and buccal patches. The tooth crown region may be cut and cleaned from jaw scan, and can be moved by staging. The digital model may also include other natural or artificial features, such as in/on-tooth objects, including attachments, power ridges, etc. (which may be used with the aligners/palatal expanders). Surfaces may overlap each other as“multiple layers” objects. The rescan may keep only the top layer. The rescan may then be rasterized. As shown in FIG. 44, a triangle in the 3D mesh can be mapped to a scan surface as a 2D triangle, then be rasterized to get all points inside the triangle (both in original 3D and 2D height map). For a point in the rasterizing grid, if there are multiple points from different surfaces, only the point with biggest height may be kept. That will fill grid with only point from top layer. Also, the rasterizing may create uniform point cloud and nice mesh.

[0230] Rescanning may include the palate patch, cut from the initial jaw scan, the buccal patch, e.g., the buccal gingiva strip cut from the initial jaw scan, and the tooth crown, from the cut tooth shape. As shown in FIGS. 45A-45B, when there are spaces 4505 between teeth, especially for space case, using this surface may result in a retainer with deep, sharp inserting shapes that may be thin and easy to break.

Thus, in some variations, the methods and apparatuses may include a filler between the teeth in the model that provides a surface from which the retainer may be built. FIGS. 46A-46C illustrate one example of a method in which a filler shape is used. The filler shape for retainer may be any appropriate shape, for example, as shown in FIGS. 46A-46B, a U-shape that includes a curved surface, and center is the scan axis curve. In some variations, the radius/distance to scan axis may be about 1 mm, and the filler shape may pass through all teeth to cover any space. Thus, in some variations, a retainer formed when filler is used may avoid the thin shapes between teeth, as shown in FIG. 46C.

[0231] While or after the 2D height map has been completed (including any modification to the map, e.g., to include filler regions, etc.) the boundaries of the putative retainer may be defined. The boundaries may depend on the intended configuration of the retainer, including any of the retainers illustrated above (e.g., in FIGS. 1A-15D and 24A-27). Boundaries may be set using the mesh from a point cloud. For example, by rescan (rasterizing), originally meshes may be converted to a point cloud in 3D, and mapped to 2D height map as described above. A new mesh may be built from the 2D points by a triangulation algorithm, including in some variations the use of a constraining technique such as Delaunay triangulation or any other appropriate technique, which may be used to build clean and correct meshes can be build. FIGS. 47A-47B illustrate one example of the use of a triangulation technique to set or define the boundaries.

[0232] In one example of a retainer having an anterior pocket for anterior teeth and two posterior pocket for posterior teeth as well as a palatal region, the methods and apparatuses described herein may build a boundary from a buccal side gingiva line of molar, the middle edge point of crown, lingual cut out points of primary teeth, with a distance to tooth, for example, 2 mm, the buccal side gingiva line of anterior teeth, and a posterior boundary curve. This is illustrated in FIG. 48. A spline curve may be constructed and resampled to create dense points as boundary points in triangulation algorithm.

[0233] In some variations, as shown in FIG. 49, a lingual cut out point may be a point in the palate surface, with a distance in 3D (for example 1.0 mm) to the middle point of each tooth’s lingual gingiva line. The posterior boundary may be a smooth U shape curve, with a distance to the last molar’ s posterior boundary; for a flat posterior, the distance is about 0 mm; for a U-shape, the distance may be about, e.g., 7.5 mm (e.g., between about 1 mm and about 12 mm), for a deep U-shape, the distance may be about, e.g., 15 mm (e.g., between about 12.1 mm and about 25 mm, etc.).

[0234] The methods and apparatuses described herein may modify the boundary to remove discontinuities and loops. For example, the boundary curve is typically a smooth spline in 3D that may be resampled as polygon and mapped into to 2D height map as boundary for triangulation. In some case, a small loop/overlap of polygon regions may occur (see, e.g., FIG. 50A), which may cause create incorrect mesh or prevent the methods and/or apparatus from forming a retainer model. A small loop may be removed by detection self-intersection of polygon, and remove all the points of the loop, as shown in FIG. 50B.

[0235] Once the boundary has been established, a mesh may be built from the point cloud (based on the 2D height map) and boundary. For example, triangles forming a mesh of the top/outer surface of the patient’s dentition may be built by any appropriate triangulation method (e.g., such as a constrained Delaunay triangulation algorithm), using rasterized points and boundary. In some variations, the original 3D points are used as mesh vertices, so the 2D mesh may be converted to 3D mesh. FIG. 51 A illustrates the mesh of a 2D height map of the bounded portion of the patient’s dentition. A uniform and nice mesh of this surface may be formed (as shown in FIG. 51B), and a mesh of this top surface may be formed, as shown in FIG. 51C. In this example, the sample triangles are used for upper surface. Because the points are rasterized from original surfaces, the mesh is uniform and nice.

[0236] The top surface of the patient’s dentition may then be used to generate the bottom surface of the retainer. FIG. 52A shows a bottom surface based on the mesh of the top surface of the patient’ s dentition. The bottom surface should be smoothed, to remove sharp corner, tip, thin sheet and so on. The bottom surface may be dilated and eroded to remove sharp feature. For example, a point in the bottom surface may be dilated (e.g., offset) by a distance, for example 1 mm, so that the minimum distance to the original surface is at least 1 mm; it may then be eroded back by the same distance (e.g., 1 mm). This may remove a sharp shape, as shown in FIG. 52A. In this example, Point A is dilated to point B, so that its minimum distance to initial surface is R. Then B is erode back to C, with minimum distance to dilate surface that is also R. As shown in FIG. 52B, the surface may also be smoothed. For example, the normal surface may be smoothed using average of neighboring vertices.

[0237] The method or apparatus may then determine and set a clearance between the bottom surface of the putative retainer and the patient’s dentition, including the teeth, gingiva and/or palate. For example, FIG. 53 illustrates one method of determining clearance. The bottom surface may be sampled from the original palate surface and then moved with a distance (clearance) in the direction of scan curve normal, as shown. The clearance may be linearly increased with the distance to the lingual split curve. If the distance is equal to zero, the surface is in the lingual split curve. When it’s far from lingual split curve, for example greater than or equal to about 2 mm in the XY plane, there may be maximal clearance. Similarly, it’s also possible to add crown or buccal thickness.

[0238] Once the clearance between the putative retainer and the patient’s dentition has been set, e.g., defining the shape of the bottom surface, the location and shape of the opposite (e.g., top) surface may be determined. Thus, the methods and systems for performing them may determine the thickness and smoothness of the top surface. For example, the top surface points may be copied from bottom surface, added with a thickness T in the scan direction, as shown in FIG. 54A. This may then be adjusted to a 3D thickness, with a minimum distance to any point in bottom surface (shown as T in FIG. 54B).

[0239] The smoothness and thickness of the retainer may be adjusted. For example, as shown in FIG. 55 A and 55B, the thickness of the palate and crown region of the retainer may be adjusted; the palate part of retainer may be made thicker, so that it’s stiffer enough to retain the trans palate space. Similarly, the crown region may be thinner, so it’s flexible and easy to put-on and take out from crown. The thickness may be increased gradually from the transition curve (lingual ridge curve). The ridge point may be detected by checking the distance of point in the lingual occlusal direction. Ridge points from all teeth may be linked and smoothed to form the lingual ridge curve, or the thickness transition curve.

[0240] As shown in FIG. 56A and 56B, the smoothness and thickness of the top surface may also be adjusted to smooth the retainer so that the retainer is more comfort for patient’s tongue, and also to reduce stress concentration in the bending point. For example, a smooth thin pate spline surface may be fit by vertices from top central surface points of the retainer. The final outer (top) surface may be the maximum of the original top surface and the smooth TPS, as shown in FIG. 56B. Thus, the vertex may be adjusted so that the outer surface is on top of original position, filling the groove, and keeping any ridges. The thickness is not reduced and retainer is still strong.

[0241] Finally, the space of the retainer may be constructed by smoothing the edges of the digital model, as shown in FIGS. 57A-57B. Points may be rescanned from original surfaces, added by clearance, to form the bottom surface. Triangles may be built, e.g., by constrained Delaunay algorithm, with boundary as described above. The top surface may be formed by extending points from the bottom surface, added by thickness. Triangles may be approximately the same as bottom surface. Edge surfaces may be determined from the boundary points, and may be smoothed. For example, the final surface may be smoothed to make it comfort to wear. In some variations, only the surface(s) near edge is/are smoothed. Thus, the retainer may still keep the shape and mechanical properties. [0242] Optionally, in some variations, as shown in FIGS. 58A-58B a code uniquely identifying the patient and/or retainer may be included and formed into or onto the retainer. In FIG. 58 A, the retainer includes an alphanumeric code identifying the retainer that is either engraved (FIG. 58 A) or embossed (FIG. 58B) onto the retainer. For example, the identifying marking may be a tag string that includes a Patient ID (PID) +“RTN” (retainer). This identifying code may be human readable by the doctor and patient. In FIG. 58 A, the code is engraved (debossed) on the retainer surface, and particularly on either the end of the retainer or the bottom surface (facing the palatal region or teeth). In FIG. 58B, the code is embossed on top of the retainer, which may be particularly helpful if the retainer is too thin to engrave.

In some variations, the method or apparatus may create a mesh of each character and project the center of each character to a bottom or top surface of retainer, and get the surface direction. For example, a Boolean operation may be used to merge the meshes of the code (e.g., characters) and the retainer. In some variations, the code is a data matrix that may be a machine readable 2D bar code. For example, a mesh may be created from an original“black and white image” of data matrix code in which a raised block equals a black pixel. The data matrix mesh may then connected to the retainer with a short link bar. All shapes may be merged by Boolean operation. In any of these variations of the retainers and methods of making them, the code may be part of an extension from the retainer, which may be removable prior to use. For example, in FIG. 57A and 57B, a tab including the code (shown as a QR-type code) may be separated from the retainer prior to wearing the retainer. Alternatively this extension region may be left in place.

[0243] Any of the variations described herein may include spaces for erupting teeth. For example, FIGS. 31A-31B illustrates a section through a retainer 3101, 3101’ as described herein, showing a region including a space permitting eruption of a tooth while keeping the adjacent teeth from moving into this region. In FIG. 31 A, the retainer 3101 includes a gap or space. In general, the retainer should not block the eruption of permeant teeth. If necessary, a retainer may be created for erupting teeth by using a model (e.g., typodont) tooth 3105 to replace a partially erupted tooth when designing the retainer. This is shown in FIG. 31 A. The resulting space 3107 may hold the erupting tooth 3109, as it grown in, shown in FIG. 31B, showing by dashed lines 3111, the stages of growth/eruption.

[0244] Any of the apparatuses described herein may include one or more eruption guidance features for guiding erupting permanent teeth. FIG. 32, similar to FIGS. 24C, 25 and 27 include a plurality of guidance features 3205, 3205’, 3205”, 3205’”. These guidance features may be configured ridges or openings on the side of the appliance (retainer) configured to fit into the interproximal region in the erupting tooth, and particularly on either side of the erupting tooth. These guidance features may be on just one side (e.g., the lingual side) or may be on both lingual and buccal sides, as shown in FIG. 27.

[0245] In any of the variations described herein, the retainer may include one or more retainer retention attachment regions for mating with an attachment on the patient’s teeth (and/or in some variations, a TAD in the palate). For example, the retainer may be configured for coupling with one or more attachments affixed to the teeth; the attachment may be a protrusion, button, bump, hook, etc. that is affixed to the patient’s teeth, on either or both the lingual and/or buccal sides. [0246] In general, the retainer apparatuses described herein may help maintain permanent positions of the teeth and/or palate, in some variations may maintain the position of the palate while moving some of the teeth (e.g., anterior teeth). In some variations, these apparatuses may allow for primary teeth eruption, and/or may provide space for maintenance of the teeth position. The retainer apparatuses may prevent passive eruption. These apparatuses may also or alternatively be configured to maintain palatal expansion.

[0247] For example, as described above, the retainers described above may include any combination of features including full palatal width; covering the full palatal width may maintain the rigidity (e.g., for one size fits all variations, or with control of one or more of contacting the palate, offset from palate and/or the thickness of the trans palatal arch). These retainers may include one or more holes or openings, e.g., in the palatal region (which may prevent choking and reduce contact with the tissue).

These retainers may include one or more cut away regions in the side or palatal region to maximize room for the patient’s tongue, which may enhance patient comfort. This may be done as a generic, e.g., one size fits all variation or as part of a variation controlling where the trans-palatal arch covers. Any of these devices may include one or more cut-away regions arranged and/or configured for primary tooth exfoliation. These regions may include one or more eruption guidance features that may act as a guide for erupting permanent teeth. Any of these retainers may also be configured to encapsulate the permanent teeth to maintain tooth alignment, space maintenance, eruption compensation, and/or prevent passive eruption.

[0248] The retainers described herein may be free of buccal coverage of the anterior teeth (which may be for aesthetic reasons) or may have less anterior tooth coverage. In some variations the user (e.g., dental practitioner) may select the amount of coverage or no coverage. In the method of designing (e.g., automated or semi-automated, including user interface for user-guided or controlled design of retainers) the occlusal thicknesses may be user-selectable; pre-determined different occlusal thicknesses may be included or the user may manually select occlusal thickness. Similarly, the occlusal shape may be pre selected or may be user-configured (e.g., the occlusal shape may include cusps or flat regions).

[0249] As described herein, any of these apparatuses may include a marking (e.g., alphanumeric marking, symbol marking, QR codes, etc.) indicating a unique identifier and/or a part with an ID number or data matrix included in the design.

[0250] When a feature or element is herein referred to as being“on” another feature or element, it can be directly on the other feature or element or intervening features and/or elements may also be present. In contrast, when a feature or element is referred to as being“directly on” another feature or element, there are no intervening features or elements present. It will also be understood that, when a feature or element is referred to as being“connected”,“attached” or“coupled” to another feature or element, it can be directly connected, attached or coupled to the other feature or element or intervening features or elements may be present. In contrast, when a feature or element is referred to as being “directly connected”,“directly attached” or“directly coupled” to another feature or element, there are no intervening features or elements present. Although described or shown with respect to one embodiment, the features and elements so described or shown can apply to other embodiments. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed“adjacent” another feature may have portions that overlap or underlie the adjacent feature.

[0251] Terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. For example, as used herein, the singular forms“a”,“an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms“comprises” and/or“comprising,” when used in this

specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. As used herein, the term“and/or” includes any and all combinations of one or more of the associated listed items and may be abbreviated as“G.

[0252] Spatially relative terms, such as“under”,“below”,“lower”,“over”,“upper” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is inverted, elements described as“under” or“beneath” other elements or features would then be oriented“over” the other elements or features. Thus, the exemplary term“under” can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms“upwardly”,“downwardly”, “vertical”,“horizontal” and the like are used herein for the purpose of explanation only unless specifically indicated otherwise.

[0253] Although the terms“first” and“second” may be used herein to describe various

features/elements, these features/elements should not be limited by these terms, unless the context indicates otherwise. These terms may be used to distinguish one feature/element from another feature/element. Thus, a first feature/element discussed below could be termed a second feature/element, and similarly, a second feature/element discussed below could be termed a first feature/element without departing from the teachings of the present invention.

[0254] As used herein in the specification and claims, including as used in the examples and unless otherwise expressly specified, all numbers may be read as if prefaced by the word“about” or

“approximately,” even if the term does not expressly appear. The phrase“about” or“approximately” may be used when describing magnitude and/or position to indicate that the value and/or position described is within a reasonable expected range of values and/or positions. For example, a numeric value may have a value that is +/- 0.1% of the stated value (or range of values), +/- 1% of the stated value (or range of values), +/- 2% of the stated value (or range of values), +/- 5% of the stated value (or range of values), +/- 10% of the stated value (or range of values), etc. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. [0255] Although various illustrative embodiments are described above, any of a number of changes may be made to various embodiments without departing from the scope of the invention as described by the claims. For example, the order in which various described method steps are performed may often be changed in alternative embodiments, and in other alternative embodiments one or more method steps may be skipped altogether. Optional features of various device and system embodiments may be included in some embodiments and not in others. Therefore, the foregoing description is provided primarily for exemplary purposes and should not be interpreted to limit the scope of the invention as it is set forth in the claims.

[0256] The examples and illustrations included herein show, by way of illustration and not of limitation, specific embodiments in which the subject matter may be practiced. As mentioned, other embodiments may be utilized and derived there from, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Such embodiments of the inventive subject matter may be referred to herein individually or collectively by the term“invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept, if more than one is, in fact, disclosed. Thus, although specific embodiments have been illustrated and described herein, any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.